Immunization Against Luteinizing Hormone-Releasing Hormone Fusion Proteins Does Not Decrease Prostate Cancer in the Transgenic Adenocarcinoma Mouse Prostate Model

Abstract

This study was undertaken to test the effect of immunization against luteinizing hormone-releasing hormone (LHRH) fusion proteins on the development and progression of prostate cancer in the transgenic adenocarcinoma mouse prostate (TRAMP) model. Two LHRH fusion proteins, ovalbumin with seven LHRH peptides (OV-LHRH-7), and thioredoxin with seven LHRH peptides (TH-LHRH-7) were used in a cocktail vaccine. Two groups of male TRAMP mice were immunized with the cocktail. Primary immunizations were at either 4 or 8 weeks of age. LHRH immunized mice (n = 19) were compared with castrated (n = 19) and intact mice (n = 18) for testosterone concentration, tumor weight, and lifespan. Immunization against LHRH in the TRAMP mice resulted in significant production of antibodies to LHRH compared with surgically castrated and intact control mice. Testicular weight was significantly reduced in the LHRH immunized groups compared with intact control mice. Serum testosterone was reduced (P < 0.05) in the immunized mice compared with intact control mice and was not different from that of castrated mice (P > 0.05). Tumor weight was variable and inconsistent throughout all treatment groups. Lifespan was not increased by immunization against LHRH or castration. Intact control mice (lived the longest (227 ± 11 days), whereas immunized mice lived 206 ± 11 days and castrated mice lived 213 ± 13 days. Tumors from immunized TRAMP mice appeared more aggressive than tumors of castrated and intact mice, as demonstrated by 35% expression of gross lung tumors in the immunized mice whereas none were observed in the castrated or intact TRAMP mice. Prostate cancer is initially dependent upon androgens for growth and development, but cells have the ability to escape androgen dependence and progress to an androgen independent state, which was evident in this study. The TRAMP mouse model immunized against LHRH may have utility in future studies and treatments of the androgen independent prostate cancer.

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References

Huggins C, Hodges CV. Studies in prostatic cancer II. The effect of castration on advanced cancer of the prostate gland. Arch Surg 43 : 209–223, 1941.

Greenberg NM, Demayo FJ, Finegold MJ, Medina D, Tilley WD, Aspinall JO, Cunha GR, Donjacour AA, Matusik RJ, Rosen JM. Prostate cancer in a transgenic mouse. Proc Natl Acad Sci USA 92 : 3439–3443, 1995.

Gingrich J, Barrios R, Morton R, Boyce B, De Mayo F, Fingold M, Angelopoulou R, Rosen J, Greenburg N. Metastatic prostate cancer in a transgenic mouse. Cancer Res 56 : 4096–4102, 1996.

Gingrich J, Barrios R, Kattan M, Nahm H, Finegold M, Greenburg N. Androgen independent prostate cancer progression in the TRAMP model. Cancer Res 57 : 4687–4691, 1997.

Zhang Y, Rozell TG, de Avila DM, Bertrand KP, Reeves JJ. Development of recombinant ovalbumin-LHRH as a potential sterilization vaccine. Vaccine 17 : 2185–2191, 1999.

Quesnell MM, Zhang Y, de Avila DM, Bertrand KP, Reeves JJ. Immunization of male mice with luteinizing hormone-releasing hormone fusion proteins reduces testicular and accessory sex gland function. Biol Repro 63 : 347–353, 2000.

Ladd A, Walfield A, Tsong YY, Thau R. Active immunization against LHRH alone or combined with LHRH analogue treatment impedes growth of androgen dependent prostatic carcinoma. Am J Reprod Physiol 34 : 200–206, 1995.

Simms MS, Sholfield DP, Jacobs E, Michaeli D, Broome P, Humphreys JE, Bishop MC. Anti-GnRH antibodies can induce castrate levels of testosterone in patients with advanced prostate cancer. Br J Cancer 83 : 443–446, 2000.

Eng MH, Charles LG, Ross BD, Chrisp CE, Pienta KJ, Greenberg NM, Hsu CX, Sanda MG. Early castration reduces prostatic carcinogenesis in transgenic mice. Urology 54 : 1112–1119, 1999.

10.

Raghow S, Kuliyev E, Steakley M, Greenberg N, Steiner MS. Efficacious chemoprevention of primary prostate cancer by flutamide in an autochthonous transgenic model. Cancer Res 60 : 4093–4097, 2000.

11.

Wechter WJ, Leipold DD, Murray D, Quiggle D, McCracken JD, Barrios RS, Greenberg NM. E-7869 (R-flurbiprofen) inhibits progression of prostate cancer in the TRAMP mouse. Cancer Res 60 : 2203–2208, 2000.

12.

Fekete M, Redding TW, Comaru-Schally AM, Pontes JE, Connelly RW, Srkalovic G, Schally AV. Receptors for luteinizing hormone-releasing hormone, somatostatin, prolactin, and epidermal growth factor in rat and human prostate cancers and in benign prostate hyperplasia. Prostate 14 : 191–208, 1989.

13.

Emons G, Ortmann O, Schulz KD, Schally AV. Growth-inhibitory actions of analogues of luteinizing hormone releasing hormone on tumor cells. Trends in Endocrinology and Metab 8 : 355–361, 1997.

14.

Jungwirth A, Schally AV, Pinski J, Halmos G, Groot K, Armatis P, Vadillo-Buenfil M. Inhibition of in vivo proliferation of androgen-independent prostate cancers by an antagonist of growth hormone-releasing hormone. J Cancer 75 : 1585–1592, 1997.

15.

Truett GE, Heeger P, Mynatt RL, Truett AA, Walker JA, Warman ML. Peparation of PCR-quality mouse genomic DNA with hot sodium hydroxide and Tris (HotSHOT). Biotechniques 29 : 52–54, 2000.

16.

Hem A, Smith AJ, Solberg P. Saphenous vein puncture for blood sampling of the mouse, rat, hamster, gerbil, guinea pig, ferret, and mink. Lab Anim 32 : 364–368, 1998.

17.

Sad S, Gupta HM, Talwar GP, Raghupathy R. Hyporesponsiveness to a GnRH vaccine in a non-responder mouse strain is T-cell mediated. J Reprod Immunol 20 : 189–194, 1991.

18.

Han G, Foster BA, Mistry S, Buchanan G, Harris JM, Tilley WD, Greenberg NM. Hormone status selects for spontaneous somatic androgen receptor variants that demonstrate specific ligand and cofactor dependent activities in autochthonous prostate cancer. J Biol Chem 276 : 11204–11213, 2001.

19.

Gregory CW, Johnson RT, Mohler JL, French FS, Wilson EM. Androgen receptor stabilization in recurrent prostate cancer is associated with hypersensitivity to low androgen. Cancer Res 61 : 2892–2898, 2001.

20.

Linja MJ, Savinainen KJ, Saramaki OR, Tammela TL, Vessella RL, Visakorpi T. Amplification and overexpression of androgen receptor gene in hormone refractory prostate cancer. Cancer Res 61 : 3550–3555, 2001.

21.

Srkalovic G, Bokser L, Radulovic S, Korkut E, Schally AV. Receptors for luteinizing hormone releasing hormone (LHRH) in Dunning R3327 prostate cancers and rat anterior pituitaries after treatment with a sustained delivery system of LHRH antagonist SB-75. Endocrinology 127 : 3052–3060, 1990.

22.

Halmos G, Arencibia JM, Schally AV, Davis R, Bostwick DG. High incidence of receptors for luteinizing hormone releasing hormone (LHRH) and LHRH receptor gene expression in human prostate cancers. J Urol 163 : 623–629, 2000.