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Abstract

Hepatocellular carcinoma (HCC) is considered a classic inflammation-associated tumor that usually originates from chronic hepatitis, where an intense and chronic inflammatory response leads to the accumulation of mutations and eventually carcinogenesis under conditions of persistent liver injury. In recent years, immunotherapy for HCC has continued to evolve, as the liver is naturally filled with a large variety of immune cells, making hepatocellular carcinoma a more complex inflammatory microenvironment unlike other tumors. With a better understanding of the specific inflammatory microenvironment of HCC, there is an opportunity to try new therapeutic strategies for HCC immunotherapy. In this paper, we review the immunotherapy of primary liver cancer in terms of the correlation between ICI drugs, ACT therapy and the inflammatory microenvironment of HCC, summarize and discuss the progress and difficulties of immunotherapy of liver cancer, and provide more scientific guidance for immunotherapy of primary liver cancer.

Keywords

hepatocellular carcinoma immune checkpoint inhibitors Adoptive immune cell inflammatory microenvironment

Introduction

In recent years, immunotherapies for cancer, such as Immune Checkpoint Inhibitors (ICIs), tumor vaccines, Adoptive Cell Therapy (ACT), and stimulation of host immunity by targeting tumor escape mechanisms, have emerged as advanced cancer treatments. In particular, several drugs targeting immune checkpoints have been approved for the treatment of HCC.^1,2 ICIs therapies work by enhancing the preexisting anti-tumor response of T cells within the tumor, and thus the inflammatory microenvironment within the tumor is critical to the efficacy of ICIs.³ In the normal liver, a large number of immune cells are flooded to maintain hepatic homeostasis by maintaining liver tolerance and responsiveness to various antigens,⁴ and hepatophilic viruses (HBV and HCV) are able to disrupt this homeostasis and establish persistent infection, with HBV infection rates as high as 75% in HCC patients,⁵ leading to a more complex inflammatory and immune microenvironment in HCC compared to other solid tumors. Subsequently, it may affect the response rate of ICIs drugs.⁶ In contrast, Chimeric Antigen Receptor T-Cell (CAR-T) therapy, which has made a splash in the treatment of hematologic tumors, has been difficult in the treatment of solid tumors. The inflammatory microenvironment within the tumor is an important factor affecting its efficacy.⁷ With the understanding of liver immunobiology, immunotherapeutic strategies for HCC have been gradually developed, prompting the development of immunotherapy for hepatocellular carcinoma toward new combination therapies, including multiple combination regimens based on altering the inflammatory microenvironment of HCC that have received much attention.

Inflammatory microenvironment and immune checkpoint inhibitors in hepatocellular carcinoma

It is well known that cancer cells are able to evade immune surveillance and promote tumor growth and progression by activating different immune checkpoint pathways. Monoclonal antibodies targeting immune checkpoints have made great breakthroughs in cancer therapeutic approaches to promote immune-mediated tumor cell elimination. Among them, programmed cell death protein-1 and its ligand (PD-1/PD-L1) and cytotoxic Tlymphocyte antigen (CTLA-4) inhibitors have been used in hepatocellular carcinoma, but in HBV infection-associated HCC The tumor microenvironment is enriched with HBV-specific CD8⁺ T cells expressing TNF-α, which present a lower expression rate of inhibitory checkpoint molecules compared to other infiltrating T cells,⁸ which may affect the response rate in the application of ICIs for the monotherapy of HCC. The Phase III Keynote-240 trial comparing Pembrolizumab with placebo for HCC did not meet the primary endpoints of overall survival (OS) and progression-free survival (PFS).⁹ It was also found that CD 8 + T-cell activity was restored in the depleted phenotype of hepatocellular carcinoma after PD-1/PD-L1 treatment, but no significant increase in the number of CD 8 + T-cells was observed.¹⁰ Inhibition of the PD-1/PD-L1 pathway does not activate antitumor immunity if infiltrating T cells are not present in the cancer tissue, and the antitumor effect can be enhanced by increasing the number of activated CD 8 + T cells in lymph nodes and then increasing the number of CD 8 + T cells infiltrating into the tumor tissue via the anti-CTLA-4 antibody pathway.¹¹ Combination of Different ICIs for Hepatocellular Carcinoma Becomes a Hot Topic in Research, Combination of Antibodies Targeting CTLA-4 and PD-1/PD-L1 Axis Check Mate-040 Study Evaluates Efficacy and Safety of Navulizumab in Combination with Eprimar in Patients with Advanced HCC Previously Treated with Sorafenibc;The objective remission rate for the Group A regimen (nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks for four consecutive doses, followed by nivolumab 240 mg every 2 weeks) was 32% (95% CI, 20–47%), whereby accelerated approval was obtained in the United States, however, the median duration of response was not achieved.¹²

In fact, hepatocellular carcinoma has different etiologies, and only a small number of clinical trials have explored the response of liver cancer with different etiologies to ICIs. To date, there have been no rigorous clinical trials to explore the differences in drug response to ICIs from liver cancer with different degrees of liver fibrosis and steatosis, particularly steatosis, Table 1.^{13,14,15,16,17} Animal studies have shown that nonalcoholic steatohepatitis (NASH) severity correlates with PD-L1 expression in hepatocytes and non-parenchymal cells, and these results suggest that steatohepatitis-associated hepatocellular carcinoma may benefit significantly from ICIs treatment, however, they do not show more effective antitumor effects when mice receive anti-PD-1 immunotherapy.^18,19 In a preclinical model of NASH-induced HCC, immunotherapy against PD-1 amplified intratumorally activated CD8⁺ PD1+ T cells without leading to tumor regression.²⁰ This may be related to changes in subtype and function in the T cell population during the development of NAFLD-associated HCC.²¹ Different stages of liver fibrosis and steatosis have different inflammatory microenvironments in the liver, and the interaction between PD-1/PD-L1 and adaptive immunity in the microenvironment maintains a fragile balance.²² As an example, NASH tissue-resident T cells (CXCR6+/CD8+) exhibit PD1 + signatures, and ICIs lead to a disruption of the balance and hepatocyte damage, which in turn affects the efficacy of PD-1/PD-L1 drugs.²³

Table 1.

Patients with hepatocellular carcinoma receiving immunotherapy stratification analysis.

Cause analysis	HR (95% CI)	Trial phase	Liver fibrosis or steatosis stratification analysis
Nonviral-HCC	0.95 (0.74–1.22)	CheckMate-459 III¹³	No
HBV-HCC	0.77 (0.56–1.06)
HCV-HCC	0.71 (0.50–1.01)
Nonviral-HCC	0.88 (0.24–1.61)	KEYNOTE 240 III¹⁴	No
HBV-HCC	0.57 (0.35–0.93)
HCV-HCC	0.96 (0.48–1.92)
Nonviral-HCC	1.18 (0.78–1.79)	COSMIC-312 III¹⁵	No
HBV-HCC	0.53 (0.33–0.87)
HCV-HCC	1.10 (0.7 2-1.68)
Nonviral-HCC	0.91 (0.52–1.59)	IMbrave150 III¹⁶	No
HBV-HCC	0.51 (0.32–0.81)
HCV-HCC	0.43 (0.21–0.87)
Nonviral-HCC	0.74 (0.57–0.95)	HIMALAYA III¹⁷	No
HBV-HCC	0.64 (0.48–0.86)
HCV-HCC	1.06 (0.76–1.49)
NAFLD	2.6 (1.2–5.6)	Meta-analysis¹⁸	Steatosis stratification

HR: Hazard Ratio; CI: confidence intervals.

The combination of ICIs with angiogenesis inhibitors is another strategy to suppress tumors and improve the inflammatory microenvironment in hepatocellular carcinoma, which is rich in blood vessels and very rich in angiogenic gene expression, and inhibition or blockade of its receptor by vascular endothelial growth factor (VEGF) increases intra-tumor infiltration and survival of cytotoxic T lymphocytes and reduces regulatory T lymphocyte recruitment, thus providing a more favorable immunoinflammatory microenvironment for ICI antitumor activity.²⁴ Atelelizumab combined with bevacizumab immune combination regimens (T + A) became the first-line treatment for primary hepatocellular carcinoma.²⁵ However, response rates to these combinations for HCC remain low, and the reason for this is that the complex immunosuppressive internal environment within hepatocellular carcinoma prevents sufficient infiltration of CD 8 + T cells, and the lack of immunoreactive lymphocyte infiltration in approximately 40–45% of cases of primary hepatocellular carcinoma may require synergistic other strategies to promote CD8⁺ T cell trafficking into the tumor.²⁶

Investigators have begun to experiment with other therapies that can alter the inflammatory microenvironment of hepatocellular carcinoma in combination with ICIs with the aim of upregulating effector T cells infiltrating within the tumor, such as traditional transcatheter arterial chemoembolization (TACE), radiofrequency ablation (RFA) or radiation therapy have been reported to induce local inflammation in the tumor, expose tumor antigens and stimulate an autologous immune response against the tumor. NCT01853618 is a study evaluating the effect of adjuvant therapy with tremelimumab (anti-CTLA-4 antibody) after RFA or TACEc;The results showed included a partial remission rate of 26%, time to tumor progression of 7.4 months, and overall survival of 12.3 months.²⁷ There are also several clinical trials of combination therapy in progress, such as anti-PD1 combined with chemoembolization (NCT03572582) and radioembolization (NCT03033446, NCT03099564). In addition to this, other molecules of the co-inhibitory signaling pathway such as lymphocyte-activation gene 3 (LAG-3), which is associated with the induction of CD 8 + T cell depletion during chronic viral infections, and a clinical study of LAG-3 in combination with pembrolizumab in patients with metastatic melanoma showed that this combination increased activated CD8⁺ and CD4⁺ T cell counts, but there have been no clinical studies of its use in HCC.²⁸ T cell immunoglobulin and mucin domain-3 (Tim-3), another immune checkpoint receptor that limits the duration and magnitude of the T cell response, has not been reported in clinical trials.²⁹

In conclusion, these synergistic strategies that attempt to enhance the response to ICIs by improving the inflammatory microenvironment of hepatocellular carcinoma and increasing the number of infiltrating lymphocytes within HCC are based on the mobilization of the patient’s own immune system, and other approaches to increase the number of infiltrating T cells within HCC, such as ACT therapy, must also be considered.

Inflammatory microenvironment of hepatocellular carcinoma and successive immune cell therapy

Activation of immune cells

As previously mentioned, the presence of CD 8 + T cells in tumors is associated with a better prognosis, and investigators have attempted to transfer immune cells overtly into HCC patients to treat the tumors. Current clinical applications of activated immune cells for HCC treatment include cytokine-induced killer cells (CIK), tumor-infiltrating lymphocytes (TIL) and NK cells, etc. The effect of clinical trials has been controversial, and these relayed immune cells must infiltrate into the hepatocellular carcinoma tissue to function well.³⁰ Components of the inflammatory microenvironment in hepatocellular carcinoma include tumor cells, blood vessels, extracellular matrix (Extracellular matrixc, ECM), fibroblasts, lymphocytes, bone marrow-derived suppressor cells, and signaling molecules.³¹

There are many inflammatory cells in the tumor microenvironment (TME), such as: and most of these inflammatory cells are non-specific immune cells, which will inhibit the positive immune function in the tumor microenvironment, thus preventing normal immune cells from attacking tumor cells and promoting the growth of tumor. It Has been found that myeloid derived suppressor cell infiltration of murine and human gliomas is associated with reduction of tumor infiltrating lymphocytes and regulated by PD-1/PD-L1 channels.^32,33 Macrophages impede CD8 + T cells from reaching tumor cells and limit the efficacy of anti-PD-1 treatment.³⁴ In addition, Not all T cells are effector cells of the anti-tumor immune system, the well-known immunosuppressive role of CD4⁺ CD25⁺ Foxp3 Regulatory T cells in the tumor microenvironment. CD4⁺ CD25⁺ Foxp3 TReg appears to suppress various anti-tumor immune responses, including CD8⁺ T cells, Natural Killer (NK) cells macrophages, etc.^35,36,37 CD4⁺ CD25⁺ Foxp3 TRegs are significantly increased in hepatitis B and HCV-associated liver cancers,³⁸ which may lead to inhibition of ACT and the inhibition may be related to the PD-1/PD-L1 channel.³⁹

These difficulties must be overcome to improve the efficacy of ACT, and it has been found that one of the reasons for the unsatisfactory results of immunotherapy with over-imported activated T cells is the high expression of PD-1 by these in vitro-expanded activated T cells, and that knockdown of the PD-1 receptor improves the killing of tumor cells by activated T cells.⁴⁰ Suggesting to us that the combination of PD-1/PD-L1 inhibitors with permacellular transfusion may achieve good results, Zhang W et al. blocked the PD-1/PD-L1 axis in DC-CIK with Pembrolizumab to enhance its therapeutic effect on hepatocellular carcinoma.⁴¹ Another exploratory study combining ACT (DC-activated T cells) with PD-1/PD-L1 blockers in patients with advanced solid tumors achieved objective tumor regression in seven of 31 patients, including objective RR and DCR of 33.3% and 77.8%, respectively, in 10 patients with hepatocellular carcinoma, suggesting that the combination of PD-1 inhibitors blocking PD in the DC-activated T cell −1/PD-L1 axis is a promising anti-HCC therapeutic strategy.⁴² NK cells have also been used to overtreat HCC, and percutaneous cryoablation combined with allogeneic natural killer cell immunotherapy significantly improves median progression-free survival in patients with advanced hepatocellular carcinoma, and multiple allogeneic natural killer cell infusions are associated with a better prognosis in advanced hepatocellular carcinoma.⁴³ Indeed, NK cell activity is also strongly influenced by the inflammatory microenvironment of hepatocellular carcinoma, and PD-1 and PD-L1 blockade can trigger a strong NK cell response, which can be very beneficial in enhancing the effectiveness of immunotherapy.⁴⁴

Combination with ICIs improves the immunocidal activity of ACTs, but ultimately these immunoreactive cells must also infiltrate into the cancerous tissue, and researchers have been investigating factors that influence infiltration of secondary metastatic cells, such as liver fibrosis preventing platelet-derived CD44 from recognizing CD 8 + T cells and reducing infiltration of effector CD 8 + T cells.⁴⁵ Fibrosis in the inflammatory microenvironment of hepatocellular carcinoma not only affects T-cell infiltration, activated NK cells are also significantly reduced in HCC patients with fibrosis,⁴⁶ but also indirectly impairs DC-produced IL-12, leading to attenuated release of cytotoxic effector molecules, reduced NKG2D, and subsequent inhibition of activated NK cells .⁴⁷

Not only that, Extracellular matrix (ECM) with massive proliferating fibrous tissue form a hypoxic TME to prevent cytokines and cells from entering into the tumor area, and even if they enter into the tumor area, there are still many inhibitory factors in the tumor microenvironment to inhibit the play of regulatory functions, Including The tumor microenvironment affects the metabolic crosstalk between tumor cells and tumor-infiltrating immune cells,⁴⁸ In this microenvironment, adenosine, lactate, acidosis, phosphatidylserine, high extracellular K levels and hypoxia to Inhibits immune cell action, reduces the production of immunostimulating TH1 type cytokines.⁴⁹ Studies have shown that the goal of actively improving immune function with cytokines and continuous immunotherapy is difficult to achieve, tumor cells change the differentiation and function of immune cells/cytokines in the TME, The TME upregulates IFN-γ-mediated expression of the inhibitory checkpoint molecule PD-L1 and prevent immune cells from reaching tumor cells.⁵⁰ On the other hand, long-term exposure to tumor antigens also inhibits the ability of infiltrating T cells to secrete high levels of cytokines and that express inhibitory receptors such as PD-L1, lymphocyte activation gene three protein (LAG-3).⁵¹ The inflammation and cells in TME are also plastic, and at the tumor site, most immune cells may change. In the tumor microenvironment, TGF-β induces neutrophil polarization to the forward tumor phenotype, favoring tumor growth and progression.⁵² Under the induction of CD4⁺ CD25⁺ Foxp3 Tregs, NK cell function in TME is inhibited.⁵³ Hypoxia associated with the tumor microenvironment limits the transcriptional potential of T cells, immunotherapies using immune checkpoint molecule blocking have limited effectiveness in some tumors, and forced expression of hypoxia-insensitive histone demethylase Kdm8b overcomes these deficiencies and promotes antitumor T cell responses.⁵⁴

To overcome these factors one must optimize the tumor inflammatory microenvironment to stimulate an effective antitumor immune response, including improving the hypoxic state of the hepatocellular carcinoma microenvironment and modulating the cytokines associated with the inflammatory microenvironment,⁵⁵ difficulties that are prevalent for ACT and deeply troubling even for well-targeted CAR-T cell therapy.

CAR- T cells

CAR-T cells use genetic engineering to introduce a desired chimeric antigen receptor (CAR) that incorporates three major fusion proteins: single chain variable fragment (scFv) structural domain; hinge and transmembrane structural domains; and intracellular structural domain. It can specifically bind to targets and trigger downstream signals and deliver activation signals directly from scFv to T cells, specifically recognizing tumor-associated antigens and enhancing the T cell killing effect against tumor cells in a non-MHC-dependent manner.⁵⁶ Barriers to the efficacy of CAR-T for solid tumors include the lack of specific tumor antigens and a tumor immunosuppressive microenvironment that impedes CAR- T cell trafficking and infiltration to the tumor site.⁵⁷ In HCC, AFP overexpression and combined hepatic fibrosis are common, which, as discussed earlier, hampers the ability of T cells and NK cells to specifically recognize tumors in successive metastases, and the “immune fatigue” of some patients receiving standard therapies, compromising efficacy.⁵⁸ To date, only a small number of clinical trials of CAR-T therapies for HCC have been reported. Phase I clinical results of CAR- T cells targeting GPC three for advanced hepatocellular carcinoma showed that the overall survival rates of patients were 50.3%, 42.0%, and 10.5% at 6 months, 1 year, and 3 years, respectively.⁵⁹ A phase I clinical study of CAR- T cells for CEA + liver metastases showed that in six patients who completed the trial, no patient had a grade 3 or four adverse event associated with CAR-T. one patient was alive and stable at 23 months after CAR-T, and five other patients died of progressive disease.⁶⁰ These results show the difficulties of CAR-T application in the treatment of HCC.

To overcome these barriers, several strategies have emerged to improve the inflammatory microenvironment of hepatocellular carcinoma and to promote massive infiltration of auto- and peri-metastatic immune cells are the direction of research, and PD-1 knockout or enhancement of CAR- T cell infiltration by precise genomic engineering techniques may be the next generation of cellular therapies for solid tumor treatment.⁶¹ An increase in infiltrated CAR- T cells was observed in trials with combined PD-1 inhibitors, and PD-1 knockout cells had several advantages over combined treatment with CAR- T cells and anti-PD-1 mAbs. Studies have shown that PD-1 knockdown CAR- T cells may provide a safer way to overcome tumor immunosuppression, especially when disruption of binding to TCR prevents overactivation of self-reactive T cells.⁶² Our study found that knockdown PD-1 CAR-T was more time-sensitive compared to anti-PD-1 mAbs, and also observed that even after knockdown of PD-1 from CAR-T cells, the number of CAR-T cells infiltrating into the interior of hepatocellular carcinoma was still not sufficient.⁶³ Inflammatory factors can induce T-cell chemotaxis, but the liver has specific adaptive immunity and serum IL-7 concentrations are significantly reduced in HCC patients in response to chronic inflammatory stimuli, and IL-7 not only enhances peripheral and hepatic CD8⁺ cytotoxic T cells, but also enhances the killing activity of CD8⁺ T cells against HCC by inhibiting PD-1.⁶⁴ CCL19 is also an important factor in the induction of inflammatory cell chemotaxis, which is rapidly produced upon activation of inflammatory vesicles 3 (Nucleotide-bindingo ligomerizationdomain-like receptor family pyrindomaincontaining 3, NLRP3).⁶⁵ IL-7 and CCL19 were found to promote infiltration and survival of mouse CAR-T cells within tumors,⁶⁶ and a clinical trial NCT03198546 using CAR-T manufactured by genetic engineering technology that can secrete IL-7 and CCL19 targeting GPC3 to treat patients with advanced HCC was conducted and found that 32 days after CAR-T injection complete disappearance of the tumor, an astounding effect demonstrating the great potential of CAR-T combined with treatment targeting the inflammatory microenvironment of hepatocellular carcinoma.⁶⁷

A lot of HCC patients develop from chronic hepatitis B. Chronic inflammation accompanies the whole process of hepatocarcinogenesis and development, and immunotherapy of hepatocellular carcinoma inevitably has to face a complex inflammatory response. Among them, NLRP three is an important factor whose assembly is triggered by many endogenous and exogenous signals, and NLRP3 induces not only T-cell infiltration but also tumor cell scorching.⁶⁸ In recent years, the critical role of inflammasome-induced cell scorching in regulating cancer immunotherapy has begun to receive attention.

Therapeutic targets targeting the inflammatory microenvironment of liver cancer

Either suppressive therapy targeting immune checkpoints or successive immune cell therapy, or a combination of both, is ultimately limited by the tumor immune microenvironment, and to improve efficacy, the immunosuppressive environment of the tumor must be improved; adaptive immunity in the hepatocellular carcinoma microenvironment may lead to resistance to immunotherapy, whereas alteration of the tumor inflammatory microenvironment can restore normal anti-cancer immunity.⁶⁹ In HCC, various inflammatory cytokines, chemokines and growth factors, play different roles in cancer development, and the same cytokine has different and sometimes opposite roles in different tumors, even in the same individual with the same tumor and at different stages of development.⁷⁰ Therefore, elucidating the molecular mechanisms associated with the complex interactions between malignancies and various inflammatory cytokines is crucial for immunotherapy of cancer.

For HCC, long-term chronic HBV infection suppresses or activates the expression of multiple cytokines and growth factors that contribute to the establishment of an immunosuppressive environment in HCC tissue, such as NLRP 3, TGF-β, IL-6, IL-8, IL-10, IDO, arginase, adenosine, lactate, VEGF, PDGF, EGFR ligands, and molecularly induced regulatory T cell (Treg) cell accumulation and Th2 and M2 polarization are involved with hepatocellular carcinoma progression.⁷¹ Among them, NLRP three plays an important role⁷² and its role in tumor growth remains controversial; in some tumors inflammatory vesicles can promote carcinogenesis by enhancing pro-oncogenic TME or, conversely, they can exert anticancer activity by regulating focal death and the immune system.⁷³ The correlation between tumor NLRP three inflammasomes and tumor immunity has been explored in a study that included 30 cancers and looked at the relationship between NLRP three and immune CYT, HLA expression, IFN response, and TIL infiltration, and found that NLRP three inflammasome scores were highly correlated with these immune features in 15 cancers, including HCC, and infiltration of TIL with tumor NLRP three inflammasomes the highest correlation, suggesting a protective role of NLRP three inflammatory vesicles in cancer development; in contrast, a significant negative correlation with all these immune features was shown in 14 additional cancers, reflecting the complex role of NLRP three in the development of different tumors.⁷⁴

A clinicopathological study found that NLRP three inflammasome components were downregulated in liver parenchymal cells of hepatocellular carcinoma compared to surrounding noncancerous liver tissue. To elucidate the role of the multiprotein NLRP three inflammasome platform in hepatocarcinogenesis, this study analyzed its expression in normal liver tissue, peritumor hepatitis and cirrhotic tissue, and corresponding HCC tissue, which represent multiple stages of hepatocarcinogenesis. Analysis showed that the expression of all NLRP three inflammasome components was significantly downregulated in HCC tissues compared with peripheral hepatitis and cirrhotic tissues, and that loss of NLRP three inflammasomes was associated with higher HCC pathological grade and higher clinical stage in HCC patients. This is the first study to investigate the role of NLRP three inflammatory vesicles in cancer patients in clinical settings in carcinogenesis, and these data come directly from clinical patients and represent actual pathology in vivo and are more convincing than animal models. Another study identified a potential link between NLRP three inflammatory vesicles and estrogen, and estradiol (E2) significantly inhibited the malignant behavior of hepatocellular carcinoma cells by upregulating NLRP three through the MAPK pathway, and ER proteins were significantly downregulated in HCC tissues compared with normal liver tissues, and treatment targeting NLRP three improved the prognosis of HCC, and it is foreseeable that treatment targeting the improvement of the inflammatory microenvironment of hepatocellular carcinoma combined with immunotherapy will undoubtedly become a key research area in the coming years, providing new directions for adjusting immunotherapeutic strategies for hepatocellular carcinoma.

Conclusions

In summary, cancer immunotherapy has become a major breakthrough in cancer treatment in recent years, and is increasingly used in HCC, with problems being identified and attempts to solve them in animal experiments and clinical practice. With an in-depth understanding of the immunological underlying mechanisms of HBV-induced immune imbalance leading to the occurrence and development of HCC, the mutual influence of inflammatory microenvironment on immunotherapy of hepatocellular carcinoma is gaining attention, and immunotherapy for HCC should take into account the positive and negative factors associated with inflammation, which helps induce immune cell infiltration but may also lead to tumor cell proliferation and angiogenesis, and should address its role in tumorigenesis and tumor The seemingly contradictory roles in tumorigenesis and tumor control should be gradually elucidated, and optimal therapies should be rationally designed for different immune stages to enhance the antitumor immune response. Potential therapeutic approaches may transform this inflammatory environment into one that relieves immunosuppression and drives anti-tumor immunity that, when combined with other therapies, may ultimately lead to tumor cell clearance. Clinical trials are already attempting to link the inflammasome pathway to tumor immunotherapy, and the inflammasome pathway may not only mediate tumor cell scorching but also stimulate immune cells to reignite the immune system, thereby increasing the efficiency of tumor immunotherapy. In conclusion, a comprehensive analysis of the accumulation of cellular mutations and signaling alterations during the development and progression of HCC on the secretion, activation or inhibition of inflammatory factors and on the infiltration of T cells is necessary for the adoption of personalized combination immunotherapy for HCC at different immune stages.

Footnotes

Acknowledgements

We would like to thank all the study authors and collaborators.

Author Contributions

Liwei Liu: Formal analysis, Investigation, Writing-Original Draft, Data Curation, Supervision. Bo Liu: Conceptualization, Project administration, Visualization, Supervision. All authors read and approved the final manuscript.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Anhui Medical College (WJH2022006 t) and Scientific research project of Anhui Province colleges and universities (2022AH052332, KL2020A0863).

ORCID iD

Bo Liu

Appendix

References

Dyhl-Polk

Mikkelsen

Ladekarl

, et al. Clinical trials of immune checkpoint inhibitors in hepatocellular carcinoma. J Clin Med 2021; 10(12): 2662. DOI: 10.3390/jcm10122662

Plaz Torres

Lai

Piscaglia

, et al. Treatment of hepatocellular carcinoma with immune checkpoint inhibitors and applicability of first-line atezolizumab/bevacizumab in a real-life setting. J Clin Med 2021; 10(15): 3201. DOI: 10.3390/jcm10153201

Ikeda

Togashi

. Aging, cancer, and antitumor immunity. Int J Clin Oncol 2022; 27(2): 316–322. DOI: 10.1007/s10147-021-01913-z

Robinson

Harmon

O'farrelly

. Liver immunology and its role in inflammation and homeostasis. Cell Mol Immunol 2016; 13(3): 267–276. DOI: 10.1038/cmi.2016.3

Yang

Hainaut

Gores

, et al. A global view of hepatocellular carcinoma: trends, risk, prevention and management. Nat Rev Gastroenterol Hepatol 2019; 16(10): 589–604. DOI: 10.1038/s41575-019-0186-y

Liu

Jiang

Deng

, et al. Immune checkpoint inhibitors in hepatocellular carcinoma: current progresses and challenges. Front Oncol 2021; 11: 737497. DOI: 10.3389/fonc.2021.737497

Kirtane

Elmariah

Chung

, et al. Adoptive cellular therapy in solid tumor malignancies: review of the literature and challenges ahead. J Immunother Cancer 2021; 9(7): e002723. DOI: 10.1136/jitc-2021-002723

Zhao

Jin

Yang

, et al. HBV-specific CD8 T cells present higher TNF-α expression but lower cytotoxicity in hepatocellular carcinoma. Clin Exp Immunol 2020; 201(3): 289–296. DOI: 10.1111/cei.13470

Kudo

Lim

Cheng

, et al. Pembrolizumab as second-line therapy for advanced hepatocellular carcinoma: a subgroup analysis of Asian Patients in the Phase 3 KEYNOTE-240 Trial. Liver Cancer 2021; 10(3): 275–284. DOI: 10.1159/000515553

10.

Hsu

Bai

, et al. Exploring markers of exhausted CD8 T Cells to predict response to immune checkpoint inhibitor therapy for hepatocellular carcinoma. Liver Cancer 2021; 10(4): 346–359. DOI: 10.1159/000515305

11.

Santos

Adamik

Howes

, et al. Impact of checkpoint blockade on cancer vaccine-activated CD8+ T cell responses. J Exp Med 2020; 217(7): e20191369. DOI: 10.1084/jem.20191369

12.

Yau

Kang

Kim

, et al. Efficacy and safety of nivolumab plus ipilimumab in patients with advanced hepatocellular carcinoma previously treated with sorafenib: the checkmate 040 randomized clinical trial. JAMA Oncol 2020; 6(11): e204564. DOI: 10.1001/jamaoncol.2020.4564

13.

Yau

Park

Finn

, et al. CheckMate 459: A randomized, multi-center phase III study of nivolumab (NIVO) vs sorafenib (SOR) as first-line (1L) treatment in patients (pts) with advanced hepatocellular carcinoma (aHCC). Ann Oncol 2019; 30(Suppl 5): v874–v875. DOI: 10.1093/annonc/mdz394.029

14.

Finn

Ryoo

Merle

KEYNOTE-240 investigators , et al.Pembrolizumab as second-line therapy in patients with advanced hepatocellular carcinoma in KEYNOTE-240: a randomized, double-blind, phase III trial. J Clin Oncol 2020; 38(3): 193–202. DOI: 10.1200/JCO.19.01307

15.

Kelley

Yau

Cheng

, et al. VP10-2021: Cabozantinib (C) plus atezolizumab (A) versus sorafenib (S) as first-line systemic treatment for advanced hepatocellular carcinoma (aHCC): results from the randomized phase III COSMIC-312 trial. Ann Oncol 2022; 33: 114–116. DOI: 10.1016/j.annonc.2021.10.008

16.

Cheng

Qin

Ikeda

, et al. Updated efficacy and safety data from IMbrave150: Atezolizumab plus bevacizumab vs. sorafenib for unresectable hepatocellular carcinoma. J Hepatol 2022; 76(4): 862–873. DOI: 10.1016/j.jhep.2021.11.030

17.

Abou-Alfa

Chan

Kudo

, et al. Phase 3 randomized, open-label, multicenter study of tremelimumab (T) and durvalumab (D) as first-line therapy in patients (pts) with unresectable hepatocellular carcinoma (uHCC): HIMALAYA. J Clin Oncol 2022; 40: 379–379. DOI: 10.1200/jco.2022.40.4_suppl.379

18.

Pfister

Núñez

Pinyol

, et al. NASH limits anti-tumour surveillance in immunotherapy-treated HCC. Nature 2021; 592(7854): 450–456. DOI: 10.1038/s41586-021-03362-0

19.

Hoogerland

Staels

Dombrowicz

. Immune-metabolic interactions in homeostasis and the progression to NASH. Trends Endocrinol Metab 2022; 33(10): 690–709. DOI: 10.1016/j.tem.2022.07.001

20.

Zhang

Yang

. Targeting T Cell Subtypes for NAFLD and NAFLD-Related HCC Treatment: An Opinion. Front Med (Lausanne) 2021; 8: 789859. DOI: 10.3389/fmed.2021.789859

21.

Macek Jilkova

Aspord

Decaens

. Predictive factors for response to PD-1/PD-L1 checkpoint inhibition in the field of hepatocellular carcinoma: current status and challenges. Cancers (Basel) 2019; 11(10): 1554. DOI: 10.3390/cancers11101554

22.

Dudek

Pfister

Donakonda

, et al. Auto-aggressive CXCR6⁺ CD8 T cells cause liver immune pathology in NASH. Nature 2021; 592(7854): 444–449.

23.

Kato

Tabata

Kimura

, et al. Lenvatinib plus anti-PD-1 antibody combination treatment activates CD8+ T cells through reduction of tumor-associated macrophage and activation of the interferon pathway. PLoS One 2019; 14(2): e0212513. DOI: 10.1371/journal.pone.0212513

24.

Salem

Sommer

, et al. Characterization of response to atezolizumab + bevacizumab versus sorafenib for hepatocellular carcinoma: Results from the IMbrave150 trial. Cancer Med 2021; 10(16): 5437–5447. DOI: 10.1002/cam4.4090

25.

Gabrielson

Wang

, et al. Intratumoral CD3 and CD8 T-cell Densities Associated with Relapse-Free Survival in HCC. Cancer Immunol Res 2016; 4(5): 419–430. DOI: 10.1158/2326-6066.CIR-15-0110

26.

Cervello

Emma

Augello

, et al. New landscapes and horizons in hepatocellular carcinoma therapy. Aging (Albany NY) 2020; 12(3): 3053–3094. DOI: 10.18632/aging.102777

27.

Atkinson

Khattak

Haydon

, et al. Eftilagimod alpha, a soluble lymphocyte activation gene-3 (LAG-3) protein plus pembrolizumab in patients with metastatic melanoma. J Immunother Cancer 2020; 8(2): e001681. DOI: 10.1136/jitc-2020-001681

28.

Mehdizadeh

Bayatipoor

Pashangzadeh

, et al. Immune checkpoints and cancer development: Therapeutic implications and future directions. Pathol Res Pract 2021; 223: 153485. DOI: 10.1016/j.prp.2021.153485

29.

Mandriani

Pelle

' E

Pezzicoli

, et al. Adoptive T-cell immunotherapy in digestive tract malignancies: current challenges and future perspectives. Cancer Treat Rev 2021; 100. DOI: 10.1016/j.ctrv.2021.102288

30.

Degroote

Lefere

Vandierendonck

, et al. Characterization of the inflammatory microenvironment and hepatic macrophage subsets in experimental hepatocellular carcinoma models. Oncotarget 2021; 12(6): 562–577. DOI: 10.18632/oncotarget.27906

31.

Raychaudhuri

Rayman

Huang

, et al. Myeloid derived suppressor cell infiltration of murine and human gliomas is associated with reduction of tumor infiltrating lymphocytes. J Neurooncol 2015; 122(2): 293–301. DOI: 10.1007/s11060-015-1720-6

32.

Jachetti

Sangaletti

Chiodoni

, et al. Modulation of PD-1/PD-L1 axis in myeloid-derived suppressor cells by anti-cancer treatments. Cell Immunol 2021; 362: 104301. DOI: 10.1016/j.cellimm.2021.104301

33.

Peranzoni

Lemoine

Vimeux

, et al. Macrophages impede CD8 T cells from reaching tumor cells and limit the efficacy of anti-PD-1 treatment. Proc Natl Acad Sci U S A 2018; 115(17): E4041–E4050. DOI: 10.1073/pnas.1720948115

34.

Zahran

Nafady-Hego

Mansor

, et al. Increased frequency and FOXP3 expression of human CD8+CD25High+ T lymphocytes and its relation to CD4 regulatory T cells in patients with hepatocellular carcinoma. Hum Immunol 2019; 80(7): 510–516. DOI: 10.1016/j.humimm

35.

Geng

Cui

, et al. CD4+CD25+Foxp3+ regulatory T cells suppress NKG2D-mediated NK cell cytotoxicity in peripheral blood. Medicine (Baltimore) 2019; 98(22): e15722. DOI: 10.1097/MD.0000000000015722

36.

Liu

Qiu

, et al. Phenotypic and functional switch of macrophages induced by regulatory CD4+CD25+ T cells in mice. Immunol Cell Biol 2011; 89(1): 130–142. DOI: 10.1038/icb.2010.70

37.

Kakita

Kanto

Itose

, et al. Comparative analyses of regulatory T cell subsets in patients with hepatocellular carcinoma: a crucial role of CD25(-) FOXP3(-) T cells. Int J Cancer 2012; 131(11): 2573–2583. DOI: 10.1002/ijc.27535

38.

Hatam

Devoti

Rosenthal

, et al. Immune suppression in premalignant respiratory papillomas: enriched functional CD4+Foxp3+ regulatory T cells and PD-1/PD-L1/L2 expression. Clin Cancer Res 2012; 18(7): 1925–1935. DOI: 10.1158/1078-0432.CCR-11-2941

39.

LiuYang

L-W

Zhou

, et al. Improvement of cytotoxicity of autologous CIKs from patients with breast cancer to MCF-7 cells by suppressed PD-1 expression. Cancer Biomark 2017; 20(4): 609–615.

40.

Zhang

Song

Xiao

, et al. Blocking the PD-1/PD-L1 axis in dendritic cell-stimulated Cytokine-Induced Killer Cells with pembrolizumab enhances their therapeutic effects against hepatocellular carcinoma. J Cancer 2019; 10(11): 2578–2587. DOI: 10.7150/jca.26961

41.

Chen

Pan

Weng

, et al. Safety and activity of PD-1 blockade-activated DC-CIK cells in patients with advanced solid tumors. Oncoimmunology 2018; 7(4): e1417721. DOI: 10.1080/2162402X.2017.1417721

42.

Mehrabi

Amini

Mehrabi

. Kill and Clearance in HCC: an approach based on NK cells and macrophages. Front Oncol 2021; 11: 693076. DOI: 10.3389/fonc.2021.693076

43.

Hsu

Hodgins

Marathe

, et al. Contribution of NK cells to immunotherapy mediated by PD-1/PD-L1 blockade. J Clin Invest 2018; 128(10): 4654–4668. DOI: 10.1172/JCI99317

44.

Guidotti

Inverso

Sironi

, et al. Immunosurveillance of the liver by intravascular effector CD8(+) T cells. Cell 2015; 161(3): 486–500.

45.

Tang

Shu

Zhang

, et al. Clinical significance of the immune cell landscape in hepatocellular carcinoma patients with different degrees of fibrosis. Ann Transl Med 2019; 7(20): 528. DOI: 10.21037/atm.2019.09.122

46.

Zhao

Zhou

Xiao

, et al. Research progress in alpha-fetoprotein-induced immunosuppression of liver cancer. Mini Rev Med Chem 2022; 22: 2237–2243. DOI: 10.2174/1389557522666220218124816

47.

Wei

Wang

Wei

, et al. Metabolic crosstalk in the tumor microenvironment regulates antitumor immunosuppression and immunotherapy resisitance. Cell Mol Life Sci 2021; 78(1): 173–193. DOI: 10.1007/s00018-020-03581-0

48.

Vaupel

Multhoff

. Hypoxia-/HIF-1α-driven factors of the tumor microenvironment impeding antitumor immune responses and promoting malignant progression. Adv Exp Med Biol 2018; 1072: 171–175. DOI: 10.1007/978-3-319-91287-5_27

49.

Lurje

Hammerich

Tacke

. Dendritic cell and T cell crosstalk in liver fibrogenesis and hepatocarcinogenesis: implications for prevention and therapy of liver cancer. Int J Mol Sci 2020; 21(19): 7378. DOI: 10.3390/ijms21197378

50.

Fridlender

Albelda

. Tumor-associated neutrophils: friend or foe? [J]. Carcinogenesis 2012; 33: 949–955.

51.

Ghiringhelli

Menard

Terme

, et al. CD4+CD25+ regulatory T cells inhibit natural killer cell functions in a transforming growth factor-beta-dependent manner. J Exp Med 2005; 202: 1075–1085.

52.

Ford

Vignali

PDA

Rittenhouse

, et al. Tumor microenvironmental signals reshape chromatin landscapes to limit the functional potential of exhausted T cells. Sci Immunol 2022; 7(74): eabj9123. DOI: 10.1126/sciimmunol.abj9123

53.

Singleton

Macann

Wilson

. Therapeutic targeting of the hypoxic tumour microenvironment. Nat Rev Clin Oncol 2021; 18(12): 751–772.

54.

Hosen

. CAR T cell therapy. Immunol Med 2021; 44(2): 69–73. DOI: 10.1080/25785826.2020.1796063

55.

Rodriguez-Garcia

Palazon

Noguera-Ortega

, et al. CAR-T cells hit the tumor microenvironment: strategies to overcome tumor escape. Front Immunol 2020; 11: 1109. DOI: 10.3389/fimmu.2020.01109

56.

Pilard

Ancion

Delvenne

, et al. Cancer immunotherapy: it’s time to better predict patients’ response. Br J Cancer 2021; 125(7): 927–938. DOI: 10.1038/s41416-021-01413-x

57.

Shi

Kaseb

, et al. Chimeric antigen receptor-glypican-3 T-cell therapy for advanced hepatocellular carcinoma: results of phase I trials. Clin Cancer Res 2020; 26(15): 3979–3989. DOI: 10.1158/1078-0432.CCR-19-3259

58.

Katz

Burga

Mccormack

, et al. Phase I hepatic immunotherapy for metastases study of intra-arterial chimeric antigen receptor-modified T-cell therapy for CEA+ liver metastases. Clin Cancer Res 2015; 21(14): 3149–3159. DOI: 10.1158/1078-0432.CCR-14-1421

59.

Huang

, et al. Recent advances in CAR-T cell engineering. J Hematol Oncol 2020; 13(1): 86. DOI: 10.1186/s13045-020-00910-5

60.

Rafiq

Yeku

Jackson

, et al. Targeted delivery of a PD-1-blocking scFv by CAR-T cells enhances anti-tumor efficacy in vivo. Nat Biotechnol 2018; 36(9): 847–856. DOI: 10.1038/nbt.4195

61.

Liu

Yang

, et al. Killing efficiency affected by mutually modulated PD-1 and PD-L1 expression via NKT-hepatoma cell interactions. Immunotherapy 2021; 13(2): 113–123. DOI: 10.2217/imt-2020-0062

62.

Teng

Ding

Cai

, et al. Interleukin-7 enhances anti-tumor activity of CD8+ T cells in patients with hepatocellular carcinoma. Cytokine 2019; 118: 115–123. DOI: 10.1016/j.cyto.2018.04.003

63.

Weatherly

Shane

Friend

, et al. Topical application of the antimicrobial agent triclosan induces NLRP3 inflammasome activation and mitochondrial dysfunction. Toxicol Sci 2020; 176(1): 147–161. DOI: 10.1093/toxsci/kfaa056

64.

Adachi

Kano

Nagai

, et al. IL-7 and CCL19 expression in CAR-T cells improves immune cell infiltration and CAR-T cell survival in the tumor. Nat Biotechnol 2018; 36(4): 346–351. DOI: 10.1038/nbt.4086

65.

Adachi

Kano

Nagai

, et al. IL-7 and CCL19 expression in CAR-T cells improves immune cell infiltration and CAR-T cell survival in the tumor. Nat Biotechnol 2018; 36(4): 346–351.

66.

Zhang

Yang

Sun

, et al. Alpinumisoflavone suppresses hepatocellular carcinoma cell growth and metastasis via NLRP3 inflammasome-mediated pyroptosis. Pharmacol Rep 2020; 72(5): 1370–1382. DOI: 10.1007/s43440-020-00064-8

67.

Oura

Morishita

Tani

, et al. Tumor immune microenvironment and immunosuppressive therapy in hepatocellular carcinoma: a review. Int J Mol Sci 2021; 22(11): 5801. DOI: 10.3390/ijms22115801

68.

Singh

Baby

Rajguru

, et al. Inflammation and cancer. Ann Afr Med 2019; 18(3): 121–126. DOI: 10.4103/aam.aam_56_18

69.

Yiang

Cheng

, et al. Molecular targets in hepatocarcinogenesis and implications for therapy. Clin Med 2018; 7(8): 213. DOI: 10.3390/jcm7080213

70.

Sharma

Kanneganti

. NLRP3 inflammasome in cancer and metabolic diseases. Nat Immunol 2021; 22(5): 550–559. DOI: 10.1038/s41590-021-00886-5

71.

Hamarsheh

Zeiser

. NLRP3 inflammasome activation in cancer: a double-edged sword. Front Immunol 2020; 11: 1444. DOI: 10.3389/fimmu.2020.01444

72.

Moossavi

Parsamanesh

Bahrami

, et al. Role of the NLRP 3 inflammasome in cancer [J]. Molecular Cancer 2018; 17(1): 1–13.

73.

Wei

, et al. Deregulation of the NLRP3 inflammasome in hepatic parenchymal cells during liver cancer progression. Lab Invest 2014; 94(1): 52–62. DOI: 10.1038/labinvest.2013.126

74.

Wei

Zhu

, et al. E2-induced activation of the NLRP3 inflammasome triggers pyroptosis and inhibits autophagy in HCC Cells. Oncol Res 2019; 27(7): 827–834. DOI: 10.3727/096504018X15462920753012

Inflammatory microenvironment and immunotherapy in hepatocellular carcinoma

Abstract

Keywords

Introduction

Inflammatory microenvironment and immune checkpoint inhibitors in hepatocellular carcinoma

Inflammatory microenvironment of hepatocellular carcinoma and successive immune cell therapy

Activation of immune cells

CAR- T cells

Therapeutic targets targeting the inflammatory microenvironment of liver cancer

Conclusions

Footnotes

Acknowledgements

Author Contributions

Declaration of Conflicting Interests

Funding

ORCID iD

Appendix

References