The Inhibitory Effect of a Novel Cytotoxic Somatostatin Analogue AN-162 on Experimental Glioblastoma

Abstract

Glioblastoma multiforme is the most common and most aggressive type of high grade tumor with a poor prognosis upon discovery. Based on earlier promising results earned with AN-162, a doxorubicin molecule linked to somatostatin (SST) analogue RC-160, it was our aim to determine the effect of AN-162 on DBTRG-05 glioblastoma cell line, and to test its efficacy in experimental brain tumors. We detected the expression of mRNA for somatostatin receptor (SSTR) subtypes 2 and 3 in DBTRG-05 cells with RT-PCR. Using ligand competition assay, specific high affinity receptors for somatostatin were found. The MTT assay showed that both AN-162 and doxorubicin (DOX) significantly inhibited cell proliferation and that there was no significant difference between the effects in vitro. Nude mice were xenografted with DBTRG-05 glioblastoma tumors. AN-162 showed a significant inhibition of tumor growth compared with the control group and the groups treated with equimolar doses of doxorubicin, somatostatin analogue RC-160, or the unconjugated mixture of doxorubicin plus RC-160. The tumor doubling time in the group of animals treated with AN-162 was extended and was significantly different from doubling times in the control group and in the other treatment groups. Our study clearly demonstrates a potent inhibitory effect of AN-162 in experimental glioblastoma, thus suggesting the possibility of its utilization in patients suffering from malignant brain cancer.

Key words

AN-162 - glioblastoma - doxorubicine - targeted therapy - somatostatin

References

• 1 Wen PY, Kesari S. Malignant gliomas in adults.  N Engl J Med. 2008;  359 492-507
• 2 Bidros DS, Vogelbaum MA. Novel drug delivery strategies in neuro-oncology.  Neurotherapeutics. 2009;  6 539-546
• 3 De Angelis LM. Brain tumors.  N Engl J Med. 2001;  344 114-123
• 4 Pozsgai E, Gomori E, Szigeti A, Boronkai A, Gallyas Jr F, Sumegi B, Bellyei S. Correlation between the progressive cytoplasmic expression of a novel small heat shock protein (Hsp16.2) and malignancy in brain tumors.  BMC Cancer. 2007;  7 233
• 5 Li SW, Qiu XG, Chen BS, Zhang W, Ren H, Wang ZC, Jiang T. Prognostic factors influencing clinical outcomes of glioblastoma multiforme.  Chin Med J (Engl). 2009;  122 1245-1249
• 6 Balmaceda C. Advances in brain tumor chemosensitivity.  Curr Opin Oncol. 1998;  10 194-200
• 7 Wolff JE, Trilling T, Molenkamp G, Egeler RM, Jurgens H. Chemosensitivity of glioma cells in vitro: a meta analysis.  J Cancer Res Clin Oncol. 1999;  125 481-486
• 8 Lesniak MS, Upadhyay U, Goodwin R, Tyler B, Brem H. Local delivery of doxorubicin for the treatment of malignant brain tumors in rats.  Anticancer Res. 2005;  25 3825-3831
• 9 Hekmatara T, Bernreuther C, Khalansky AS, Theisen A, Weissenberger J, Matschke J, Gelperina S, Kreuter J, Glatzel M. Efficient systemic therapy of rat glioblastoma by nanoparticle-bound doxorubicin is due to antiangiogenic effects.  Clin Neuropathol. 2009;  28 153-164
• 10 Inoue T, Yamashita Y, Nishihara M, Sugiyama S, Sonoda Y, Kumabe T, Yokoyama M, Tominaga T. Therapeutic efficacy of a polymeric micellar doxorubicin infused by convection-enhanced delivery against intracranial 9L brain tumor models.  Neuro Oncol. 2009;  11 151-157
• 11 Fabel K, Dietrich J, Hau P, Wismeth C, Winner B, Przywara S, Steinbrecher A, Ullrich W, Bogdahn U. Long-term stabilization in patients with malignant glioma after treatment with liposomal doxorubicin.  Cancer. 2001;  92 1936-1942
• 12 Vaage J, Barbera-Guillem E, Abra R, Huang A, Working P. Tissue distribution and therapeutic effect of intravenous free or encapsulated liposomal doxorubicin on human prostate carcinoma xenografts.  Cancer. 1994;  73 1478-1484
• 13 Brazeau P, Vale W, Burgus R, Ling N, Butcher M, Rivier J, Guillemin R. Hypothalamic polypeptide that inhibits the secretion of immunoreactive pituitary growth hormone.  Science. 1973;  179 77-79
• 14 Pollak MN, Schally AV. Mechanisms of antineoplastic action of somatostatin analogs.  Proc Soc Exp Biol Med. 1998;  217 143-152
• 15 Bauer W, Briner U, Doepfner W, Haller R, Huguenin R, Marbach P, Petcher TJ, Pless. SMS 201-995: a very potent and selective octapeptide analogue of somatostatin with prolonged action.  Life Sci. 1982;  31 1133-1140
• 16 Cai RZ, Szoke B, Lu R, Fu D, Redding TW, Schally AV. Synthesis and biological activity of highly potent octapeptide analogs of somatostatin.  Proc Natl Acad Sci USA. 1986;  83 1896-1900
• 17 Weckbecker G, Raulf F, Stolz B, Bruns C. Somatostatin analogs for diagnosis and treatment of cancer.  Pharmacol Ther. 1993;  60 245-264
• 18 Srkalovic G, Cai RZ, Schally AV. Evaluation of receptors for somatostatin in various tumors using different analogs.  J Clin Endocrinol Metab. 1990;  70 661-669
• 19 Buscail L, Delesque N, Esteve JP, Saint-Laurent N, Prats H, Clerc P, Robberecht P, Bell GI, Liebow C, Schally AV. et al . Stimulation of tyrosine phosphatase and inhibition of cell proliferation by somatostatin analogues: mediation by human somatostatin receptor subtypes SSTR1 and SSTR2.  Proc Natl Acad Sci USA. 1994;  91 2315-2319
• 20 Reubi JC, Schaer JC, Laissue JA, Waser B. Somatostatin receptors and their subtypes in human tumors and in peritumoral vessels.  Metabolism. 1996;  45 39-41
• 21 Buscail L, Esteve JP, Saint-Laurent N, Bertrand V, Reisine T, O’Carroll AM, Bell GI, Schally AV, Vaysse N, Susini C. Inhibition of cell proliferation by the somatostatin analogue RC-160 is mediated by somatostatin receptor subtypes SSTR2 and SSTR5 through different mechanisms.  Proc Natl Acad Sci USA. 1995;  92 1580-1584
• 22 Patel YC, Greenwood MT, Panetta R, Demchyshyn L, Niznik H, Srikant CB. The somatostatin receptor family.  Life Sci. 1995;  57 1249-1265
• 23 Reisine T, Bell GI. Molecular biology of somatostatin receptors.  Endocr Rev. 1995;  16 427-442
• 24 Kalkner KM, Janson ET, Nilsson S, Carlsson S, Oberg K, Westlin JE. Somatostatin receptor scintigraphy in patients with carcinoid tumors: comparison between radioligand uptake and tumor markers.  Cancer Res. 1995;  55 5801s-5804s
• 25 Klagge A, Krause K, Schierle K, Steinert F, Dralle H, Fuhrer D. Somatostatin receptor subtype expression in human thyroid tumours.  Horm Metab Res. 2010;  42 237-240
• 26 Cordelier P, Esteve JP, Bousquet C, Delesque N, O'Carroll AM, Schally AV, Vaysse N, Susini C, Buscail L. Characterization of the antiproliferative signal mediated by the somatostatin receptor subtype sst5.  Proc Natl Acad Sci USA. 1997;  94 9343-9348
• 27 Lamberts SW, van der Lely AJ, de Herder WW, Hofland LJ. Octreotide.  N Engl J Med. 1996;  334 246-254
• 28 Reubi JC, Laissue JA. Multiple actions of somatostatin in neoplastic disease.  Trends Pharmacol Sci. 1995;  16 110-115
• 29 Reubi JC, Waser B, Schaer JC, Markwalder R. Somatostatin receptors in human prostate and prostate cancer.  J Clin Endocrinol Metab. 1995;  80 2806-2814
• 30 Luque-Ramirez M, Portoles GR, Varela C, Albero R, Halperin I, Moreiro J, Soto A, Casamitjana R. The efficacy of octreotide LAR as firstline therapy for patients with newly diagnosed acromegaly is independent of tumor extension: predictive factors of tumor and biochemical response.  Horm Metab Res. 2010;  42 38-44
• 31 Plonowski A, Nagy A, Schally AV, Sun B, Groot K, Halmos G. In vivo inhibition of PC-3 human androgen-independent prostate cancer by a targeted cytotoxic bombesin analogue, AN-215.  Int J Cancer. 2000;  88 652-657
• 32 Sun B, Schally AV, Halmos G. The presence of receptors for bombesin/GRP and mRNA for three receptor subtypes in human ovarian epithelial cancers.  Regul Pept. 2000;  90 77-84
• 33 Ziegler CG, Brown JW, Schally AV, Erler A, Gebauer L, Treszl A, Young L, Fishman LM, Engel JB, Willenberg HS, Petersenn S, Eisenhofer G, Ehrhart-Bornstein M, Bornstein SR. Expression of neuropeptide hormone receptors in human adrenal tumors and cell lines: antiproliferative effects of peptide analogues.  Proc Natl Acad Sci USA. 2009;  106 15879-15884
• 34 Seitz S, Schally AV, Treszl A, Papadia A, Rick F, Szalontay L, Szepeshazi K, Ortmann O, Halmos G, Hohla F, Buchholz S. Preclinical evaluation of properties of a new targeted cytotoxic somatostatin analog, AN-162 (AEZS-124), and its effects on tumor growth inhibition.  Anticancer Drugs. 2009;  20 553-558
• 35 Treszl A, Schally AV, Seitz S, Szalontay L, Rick FG, Szepeshazi K, Halmos G. Inhibition of human non-small cell lung cancers with a targeted cytotoxic somatostatin analog, AN-162.  Peptides. 2009;  30 1643-1650
• 36 Banks WA, Schally AV, Barrera CM, Fasold MB, Durham DA, Csernus VJ, Groot K, Kastin AJ. Permeability of the murine blood-brain barrier to some octapeptide analogs of somatostatin.  Proc Natl Acad Sci USA. 1990;  87 6762-6766
• 37 Nagy A, Schally AV, Halmos G, Armatis P, Cai RZ, Csernus V, Kovacs M, Koppan M, Szepeshazi K, Kahan Z. Synthesis and biological evaluation of cytotoxic analogs of somatostatin containing doxorubicin or its intensely potent derivative, 2-pyrrolinodoxorubicin.  Proc Natl Acad Sci USA. 1998;  95 1794-1799
• 38 Halmos G, Schally AV, Sun B, Davis R, Bostwick DG, Plonowski A. High expression of somatostatin receptors and messenger ribonucleic acid for its receptor subtypes in organ-confined and locally advanced human prostate cancers.  J Clin Endocrinol Metab. 2000;  85 2564-2571
• 39 Benjamin RS. Pharmacokinetics of adriamycin (NSC-123127) in patients with sarcomas.  Cancer Chemother Rep. 1974;  58 271-273
• 40 Benjamin RS, Riggs Jr. CE, Bachur NR. Pharmacokinetics and metabolism of adriamycin in man.  Clin Pharmacol Ther. 1973;  14 592-600
• 41 Schally A, Nagy A. Targeted cytotoxic analogs of luteinizing hormone-releasing hormone: a reply.  Eur J Endocrinol. 2001;  144 559
• 42 Schally AV, Nagy A. Cancer chemotherapy based on targeting of cytotoxic peptide conjugates to their receptors on tumors.  Eur J Endocrinol. 1999;  141 1-14
• 43 Halmos G, Schally AV, Comaru-Schally AM, Nagy A, Irimpen A. Absence of binding of targeted analogs of somatostatin carrying cytotoxic radicals or radionuclides to growth hormone secretagogue receptors on human myocardium.  Life Sci. 2003;  72 2669-2674
• 44 Engel JB, Schally AV, Dietl J, Rieger L, Honig A. Targeted therapy of breast and gynecological cancers with cytotoxic analogues of peptide hormones.  Mol Pharm. 2007;  4 652-658
• 45 Szepeshazi K, Schally AV, Halmos G. LH-RH receptors in human colorectal cancers: unexpected molecular targets for experimental therapy.  Int J Oncol. 2007;  30 1485-1492
• 46 Kidd M, Schally AV, Pfragner R, Malfertheiner MV, Modlin IM. Inhibition of proliferation of small intestinal and bronchopulmonary neuroendocrine cell lines by using peptide analogs targeting receptors.  Cancer. 2008;  112 1404-1414
• 47 Kiaris H, Schally AV, Nagy A, Sun B, Szepeshazi K, Halmos G. Regression of U-87 MG human glioblastomas in nude mice after treatment with a cytotoxic somatostatin analog AN-238.  Clin Cancer Res. 2000;  6 709-717
• 48 Banks WA, Kastin AJ, Radulovic S, Conley FK, Johnson DL, Schally AV. Selective uptake of the somatostatin analog RC-160 across the blood-brain tumor barrier of mice with KHT sarcomas.  Anticancer Drugs. 1992;  3 519-523
• 49 Hau P, Fabel K, Baumgart U, Rummele P, Grauer O, Bock A, Dietmaier C, Dietmaier W, Dietrich J, Dudel C, Hubner F, Jauch T, Drechsel E, Kleiter I, Wismeth C, Zellner A, Brawanski A, Steinbrecher A, Marienhagen J, Bogdahn U. Pegylated liposomal doxorubicin-efficacy in patients with recurrent high-grade glioma.  Cancer. 2004;  100 1199-1207
• 50 Liang BC, Thornton Jr. AF, Sandler HM, Greenberg HS. Malignant astrocytomas: focal tumor recurrence after focal external beam radiation therapy.  J Neurosurg. 1991;  75 559-563
• 51 Merker PC, Lewis MR, Walker MD, Richardson Jr. EP. Neurotoxicity of adriamycin (doxorubicin) perfused through the cerebrospinal fluid spaces of the rhesus monkey.  Toxicol Appl Pharmacol. 1978;  44 191-205
• 52 Neuwelt EA, Pagel M, Barnett P, Glassberg M, Frenkel EP. Pharmacology and toxicity of intracarotid adriamycin administration following osmotic blood-brain barrier modification.  Cancer Res. 1981;  41 4466-4470
• 53 Schally AV, Nagy A. New approaches to treatment of various cancers based on cytotoxic analogs of LHRH, somatostatin and bombesin.  Life Sci. 2003;  72 2305-2320
• 54 Lamberts SW, de Herder WW, Hofland LJ. Somatostatin analogs in the diagnosis and treatment of cancer.  Trends Endocrinol Metab. 2002;  13 451-457
• 55 Reubi JC. Peptide receptors as molecular targets for cancer diagnosis and therapy.  Endocr Rev. 2003;  24 389-427
• 56 Barbieri F, Pattarozzi A, Gatti M, Aiello C, Quintero A, Lunardi G, Bajetto A, Ferrari A, Culler MD, Florio T. Differential Efficacy of Sstr1, 2 and 5 Agonists in the Inhibition of C6 Glioma Growth in Nude Mice.  Am J Physiol Endocrinol Metab. 2009; 
• 57 Massa A, Barbieri F, Aiello C, Iuliano R, Arena S, Pattarozzi A, Corsaro A, Villa V, Fusco A, Zona G, Spaziante R, Schettini G, Florio T. The phosphotyrosine phosphatase eta mediates somatostatin inhibition of glioma proliferation via the dephosphorylation of ERK1/2.  Ann N Y Acad Sci. 2004;  1030 264-274
• 58 Abe T, Hasegawa S, Taniguchi K, Yokomizo A, Kuwano T, Ono M, Mori T, Hori S, Kohno K, Kuwano M. Possible involvement of multidrug-resistance-associated protein (MRP) gene expression in spontaneous drug resistance to vincristine, etoposide and adriamycin in human glioma cells.  Int J Cancer. 1994;  58 860-864
• 59 Darling JL, Thomas DG. Response of short-term cultures derived from human malignant glioma to aziridinylbenzoquinone, etoposide and doxorubicin: an in vitro phase II trial.  Anticancer Drugs. 2001;  12 753-760
• 60 Muldoon LL, Neuwelt EA. BR96-DOX immunoconjugate targeting of chemotherapy in brain tumor models.  J Neurooncol. 2003;  65 49-62
• 61 Mamot C, Drummond DC, Greiser U, Hong K, Kirpotin DB, Marks JD, Park JW. Epidermal growth factor receptor (EGFR)-targeted immunoliposomes mediate specific and efficient drug delivery to EGFR- and EGFRvIII-overexpressing tumor cells.  Cancer Res. 2003;  63 3154-3161
• 62 Saito R, Bringas JR, McKnight TR, Wendland MF, Mamot C, Drummond DC, Kirpotin DB, Park JW, Berger MS, Bankiewicz KS. Distribution of liposomes into brain and rat brain tumor models by convection-enhanced delivery monitored with magnetic resonance imaging.  Cancer Res. 2004;  64 2572-2579
• 63 Steiniger SC, Kreuter J, Khalansky AS, Skidan IN, Bobruskin AI, Smirnova ZS, Severin SE, Uhl R, Kock M, Geiger KD, Gelperina SE. Chemotherapy of glioblastoma in rats using doxorubicin-loaded nanoparticles.  Int J Cancer. 2004;  109 759-767

Correspondence