Journal Mobile Options
Table of Contents
Vol. 87, No. 3, 2008
Issue release date: April 2008
Neuroendocrinology 2008;87:168–181
(DOI:10.1159/000111501)

Octreotide and the mTOR Inhibitor RAD001 (Everolimus) Block Proliferation and Interact with the Akt-mTOR-p70S6K Pathway in a Neuro-Endocrine Tumour Cell Line

Grozinsky-Glasberg S. · Franchi G. · Teng M. · Leontiou C.A. · Ribeiro de Oliveira Jr. A. · Dalino P. · Salahuddin N. · Korbonits M. · Grossman A.B.
aDepartment of Endocrinology, William Harvey Research Institute, Barts and The London, Queen Mary’s School of Medicine and Dentistry, University of London, London, UK; bInstitute of Endocrinology, Beilinson Hospital, Rabin Medical Center, and Sackler Faculty of Medicine, Tel Aviv, Israel; cEndocrinology Unit, ‘Vita-Salute’ San Raffaele University Hospital, and dDivisione di Endocrinologia, Ospedale Niguarda Ca’ Granda, Milan, Italy; eDepartment of Internal Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil

Individual Users: Register with Karger Login Information

Please create your User ID & Password





Contact Information











I have read the Karger Terms and Conditions and agree.

To view the fulltext, please log in

To view the pdf, please log in

Abstract

Background/Aim: The mode of action of the somatostatin analog octreotide on neuro-endocrine tumour proliferation is largely unknown. Overexpression of the proto-oncogene Akt/PKB (protein kinase B) has been demonstrated in certain neuro-endocrine tumours: Akt activates downstream proteins including mTOR and p70S6K, which play an important role in cell proliferation. RAD001 (everolimus) is a novel agent that is being trialled in the treatment of neuro-endocrine tumours, and is known to interact with mTOR. We explored the mechanism of action of octreotide, RAD001, and their combination on cell proliferation and kinase activation in a neuro-endocrine tumour cell line (rat insulinoma cell line, INS1). Methods: Proliferation assays were used to determine the effects of octreotide, RAD001, and their combination on cell proliferation. Western blotting was used to characterize the expression of phosphorylated Akt, phosphorylated TSC2, phosphorylated mTOR, and phosphorylated 70S6K. Results: Treatment with octreotide and RAD001 inhibited proliferation and attenuated phosphorylation of all downstream targets of Akt: TSC2, mTOR, and p70S6K. Conclusions: In this cell model, octreotide and RAD001 appear to act through a similar pathway and inhibit the Akt-mTOR-p70S6 kinase pathway downstream of Akt. There may be some overlapping effects of the two inhibitors on the mTOR pathway, although it is likely that other additional effects may differentiate the two agents.



Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

References

  1. Oberg K: Management of neuroendocrine tumours. Ann Oncol 2004;15(Suppl 4):iv293–iv298.

    External Resources

  2. Eriksson B, Renstrup J, Imam H, Oberg K: High-dose treatment with lanreotide of patients with advanced neuroendocrine gastrointestinal tumors: clinical and biological effects. Ann Oncol 1997;8:1041–1044.
  3. Musat M, Korbonits M, Kola B, Borboli N, Hanson MR, Nanzer AM, Grigson J, Jordan S, Morris DG, Gueorguiev M, Coculescu M, Basu S, Grossman AB: Enhanced protein kinase B/Akt signalling in pituitary tumours. Endocr Relat Cancer 2005;12:423–433.
  4. Shah T, Hochhauser D, Frow R, Quaglia A, Dhillon AP, Caplin ME: Epidermal growth factor receptor expression and activation in neuroendocrine tumours. J Neuroendocrinol 2006;18:355–360.
  5. Altomare DA, Testa JR: Perturbations of the AKT signaling pathway in human cancer. Oncogene 2005;24:7455–7464.
  6. Bellacosa A, de Feo D, Godwin AK, Bell DW, Cheng JQ, Altomare DA, Wan M, Dubeau L, Scambia G, Masciullo V, Ferrandina G, Benedetti PP, Mancuso S, Neri G, Testa JR: Molecular alterations of the AKT2 oncogene in ovarian and breast carcinomas. Int J Cancer 1995;64:280–285.
  7. Cheng JQ, Ruggeri B, Klein WM, Sonoda G, Altomare DA, Watson DK, Testa JR: Amplification of AKT2 in human pancreatic cells and inhibition of AKT2 expression and tumorigenicity by antisense RNA. Proc Natl Acad Sci U S A 1996;93:3636–3641.
  8. Vasko V, Saji M, Hardy E, Kruhlak M, Larin A, Savchenko V, Miyakawa M, Isozaki O, Murakami H, Tsushima T, Burman KD, De Micco C, Ringel MD: Akt activation and localisation correlate with tumour invasion and oncogene expression in thyroid cancer. J Med Genet 2004;41:161–170.
  9. Wu C, Huang J: PI3 kinase-AKT-mTOR pathway is essential for neuroendocrine differentiation of prostate cancer. J Biol Chem 2007;282:3571–3583.
  10. Datta SR, Brunet A, Greenberg ME: Cellular survival: a play in three Akts. Genes Dev 1999;13:2905–2927.
  11. McManus EJ, Alessi DR: TSC1-TSC2: a complex tale of PKB-mediated S6K regulation. Nat Cell Biol 2002;4:E214–E216.
  12. Cheng SW, Fryer LG, Carling D, Shepherd PR: Thr2446 is a novel mammalian target of rapamycin (mTOR) phosphorylation site regulated by nutrient status. J Biol Chem 2004;279:15719–15722.
  13. Hay N, Sonenberg N: Upstream and downstream of mTOR. Genes Dev 2004;18:1926–1945.
  14. Petroulakis E, Mamane Y, Le Bacquer O, Shahbazian D, Sonenberg N: mTOR signaling: implications for cancer and anticancer therapy. Br J Cancer 2006;94:195–199.
  15. Schally AV: Oncological applications of somatostatin analogues. Cancer Res 1988;48:6977–6985.
  16. Jensen RT: Carcinoid and pancreatic endocrine tumors: recent advances in molecular pathogenesis, localization, and treatment. Curr Opin Oncol 2000;12:368–377.
  17. Zatelli MC, Piccin D, Ambrosio MR, Bondanelli M, degli Uberti EC: Antiproliferative effects of somatostatin analogs in pituitary adenomas. Pituitary 2006;9:27–34.
  18. Resmini E, Dadati P, Ravetti JL, Zona G, Spaziante R, Saveanu A, Jaquet P, Culler MD, Bianchi F, Rebora A, Minuto F, Ferone D: Rapid pituitary tumor shrinkage with dissociation between antiproliferative and antisecretory effects of a long-acting octreotide in an acromegalic patient. J Clin Endocrinol Metab 2007;92:1592–1599.
  19. Pinski J, Schally AV, Halmos G, Szepeshazi K: Effect of somatostatin analog RC-160 and bombesin/gastrin releasing peptide antagonist RC-3095 on growth of PC-3 human prostate-cancer xenografts in nude mice. Int J Cancer 1993;55:963–967.
  20. Pinski J, Halmos G, Yano T, Szepeshazi K, Qin Y, Ertl T, Schally AV: Inhibition of growth of MKN45 human gastric-carcinoma xenografts in nude mice by treatment with bombesin/gastrin-releasing-peptide antagonist (RC-3095) and somatostatin analogue RC-160. Int J Cancer 1994;57:574–580.
  21. Pinski J, Schally AV, Halmos G, Szepeshazi K, Groot K: Somatostatin analog RC-160 inhibits the growth of human osteosarcomas in nude mice. Int J Cancer 1996;65:870–874.
  22. Radulovic S, Miller G, Schally AV: Inhibition of growth of HT-29 human colon cancer xenografts in nude mice by treatment with bombesin/gastrin releasing peptide antagonist (RC-3095). Cancer Res 1991;51:6006–6009.
  23. Faivre S, Kroemer G, Raymond E: Current development of mTOR inhibitors as anticancer agents. Nat Rev Drug Discov 2006;5:671–688.
  24. Lang SA, Gaumann A, Koehl GE, Seidel U, Bataille F, Klein D, Ellis LM, Bolder U, Hofstaedter F, Schlitt HJ, Geissler EK, Stoeltzing O: Mammalian target of rapamycin is activated in human gastric cancer and serves as a target for therapy in an experimental model. Int J Cancer 2007;120:1803–1810.
  25. Mabuchi S, Altomare DA, Connolly DC, Klein-Szanto A, Litwin S, Hoelzle MK, Hensley HH, Hamilton TC, Testa JR: RAD001 (everolimus) delays tumor onset and progression in a transgenic mouse model of ovarian cancer. Cancer Res 2007;67:2408–2413.
  26. Zeng Z, Sarbassov dos D, Samudio IJ, Yee KW, Munsell MF, Ellen Jackson C, Giles FJ, Sabatini DM, Andreeff M, Konopleva M: Rapamycin derivatives reduce mTORC2 signaling and inhibit AKT activation in AML. Blood 2007;109:3509–3512.
  27. Guba M, von Breitenbuch P, Steinbauer M, Koehl G, Flegel S, Hornung M, Bruns CJ, Zuelke C, Farkas S, Anthuber M, Jauch KW, Geissler EK: Rapamycin inhibits primary and metastatic tumor growth by antiangiogenesis: involvement of vascular endothelial growth factor. Nat Med 2002;8:128–135.
  28. Holash J, Thurston G, Rudge JS, Yancopoulos GD, Adjei AA, Bergers G, Pytowski B, Pegram M, Gordon MS: Inhibitors of growth factor receptors, signaling pathways and angiogenesis as therapeutic molecular agents. Cancer Metastasis Rev 2006;25:243–252.
  29. Lane HA, Lebwohl D: Future directions in the treatment of hormone-sensitive advanced breast cancer: the RAD001 (everolimus)-letrozole clinical program. Semin Oncol 2006;33(2 Suppl 7):S18–S25.

    External Resources

  30. Theodoropoulou M, Zhang J, Laupheimer S, Paez-Pereda M, Erneux C, Florio T, Pagotto U, Stalla GK: Octreotide, a somatostatin analogue, mediates its antiproliferative action in pituitary tumor cells by altering phosphatidylinositol 3-kinase signaling and inducing Zac1 expression. Cancer Res 2006;66:1576–1582.
  31. Calvo V, Crews CM, Vik TA, Bierer BE: Interleukin 2 stimulation of p70 S6 kinase activity is inhibited by the immunosuppressant rapamycin. Proc Natl Acad Sci USA 1992;89:7571–7575.
  32. Chou MM, Blenis J: The 70 kDa S6 kinase: regulation of a kinase with multiple roles in mitogenic signalling. Curr Opin Cell Biol 1995;7:806–814.
  33. Chung J, Kuo CJ, Crabtree GR, Blenis J: Rapamycin-FKBP specifically blocks growth-dependent activation of and signaling by the 70-kD S6 protein kinases. Cell 1992;69:1227–1236.
  34. Ferrari S, Pearson RB, Siegmann M, Kozma SC, Thomas G: The immunosuppressant rapamycin induces inactivation of p70s6k through dephosphorylation of a novel set of sites. J Biol Chem 1993;268:16091–16094.
  35. Ferrari S, Thomas G: S6 phosphorylation and the p70s6k/p85s6k. Crit Rev Biochem Mol Biol 1994;29:385–413.
  36. Kuo CJ, Chung J, Fiorentino DF, Flanagan WM, Blenis J, Crabtree GR: Rapamycin selectively inhibits interleukin-2 activation of p70 S6 kinase. Nature 1992;358:70–73.
  37. Price DJ, Grove JR, Calvo V, Avruch J, Bierer BE: Rapamycin-induced inhibition of the 70-kilodalton S6 protein kinase. Science 1992;257:973–977.
  38. Morris DG, Kola B, Borboli N, Kaltsas GA, Gueorguiev M, McNicol AM, Ferrier R, Jones TH, Baldeweg S, Powell M, Czirjak S, Hanzely Z, Johansson JO, Korbonits M, Grossman AB: Identification of adrenocorticotropin receptor messenger ribonucleic acid in the human pituitary and its loss of expression in pituitary adenomas. J Clin Endocrinol Metab 2003;88:6080–6087.
  39. Saltz L, Trochanowski B, Buckley M, Heffernan B, Niedzwiecki D, Tao Y, Kelsen D: Octreotide as an antineoplastic agent in the treatment of functional and nonfunctional neuroendocrine tumors. Cancer 1993;72:244–248.
  40. Balsara BR, Pei J, Mitsuuchi Y, Page R, Klein-Szanto A, Wang H, Unger M, Testa JR: Frequent activation of AKT in non-small cell lung carcinomas and preneoplastic bronchial lesions. Carcinogenesis 2004;25:2053–2059.
  41. Bellacosa A, Kumar CC, Di Cristofano A, Testa JR: Activation of AKT kinases in cancer: implications for therapeutic targeting. Adv Cancer Res 2005;94:29–86.
  42. Hay N: The Akt-mTOR tango and its relevance to cancer. Cancer Cell 2005;8:179–183.
  43. Houghton PJ, Huang S: mTOR as a target for cancer therapy. Curr Top Microbiol Immunol 2004;279:339–359.
  44. Testa JR, Bellacosa A: AKT plays a central role in tumorigenesis. Proc Natl Acad Sci USA 2001;98:10983–10985.
  45. Testa JR, Tsichlis PN: AKT signaling in normal and malignant cells. Oncogene 2005;24:7391–7393.
  46. Tanno S, Tanno S, Mitsuuchi Y, Altomare DA, Xiao GH, Testa JR: AKT activation up-regulates insulin-like growth factor I receptor expression and promotes invasiveness of human pancreatic cancer cells. Cancer Res 2001;61:589–593.
  47. Tanno S, Yanagawa N, Habiro A, Koizumi K, Nakano Y, Osanai M, Mizukami Y, Okumura T, Testa JR, Kohgo Y: Serine/threonine kinase AKT is frequently activated in human bile duct cancer and is associated with increased radioresistance. Cancer Res 2004;64:3486–3490.
  48. Wang HQ, Altomare DA, Skele KL, Poulikakos PI, Kuhajda FP, Di Cristofano A, Testa JR: Positive feedback regulation between AKT activation and fatty acid synthase expression in ovarian carcinoma cells. Oncogene 2005;24:3574–3582.
  49. Yao JC, Phan A, Chang DZ, Wolff RA, Jacobs C, Mares JE, Gupta S, Meric-Bernstam F, Rashid A: Phase II study of RAD001 (everolimus) and depot octreotide (sandostatin LAR) in advanced low-grade neuroendocrine carcinoma (LGNET). Abstr ASCO Annu Meet Proc Part I. J Clin Oncol 2007;25(Suppl 18):4503.
  50. Arnold R, Trautmann ME, Creutzfeldt W, Benning R, Benning M, Neuhaus C, Jürgensen R, Stein K, Schäfer H, Bruns C, Dennler HJ: Somatostatin analogue octreotide and inhibition of tumour growth in metastatic endocrine gastroenteropancreatic tumours. Gut 1996;38:430–438.
  51. Eriksson B, Oberg K: Summing up 15 years of somatostatin analog therapy in neuroendocrine tumors: future outlook. Ann Oncol 1999;10(Suppl 2):S31–S38.
  52. Saltz L, Trochanowski B, Buckley M, Heffernan B, Niedzwiecki D, Tao Y, Kelsen D: Octreotide as an antineoplastic agent in the treatment of functional and nonfunctional neuroendocrine tumors. Cancer 1993;72:244–248.
  53. Astruc B, Marbach P, Bouterfa H, Denot C, Safari M, Vitaliti A, Sheppard M: Long-acting octreotide and prolonged-release lanreotide formulations have different pharmacokinetic profiles. J Clin Pharmacol 2005;45:836–844.
  54. Oshiro N, Yoshino K, Hidayat S, Tokunaga C, Hara K, Eguchi S, Avruch J, Yonezawa K: Dissociation of raptor from mTOR is a mechanism of rapamycin-induced inhibition of mTOR function. Genes Cells 2004;9:359–366.
  55. Zitzmann K, De Toni EN, Brand S, Göke B, Meinecke J, Spöttl G, Meyer HH, Auernhammer CJ: The novel mTOR inhibitor RAD001 (everolimus) induces antiproliferative effects in human pancreatic neuroendocrine tumor cells. Neuroendocrinology 2007;85:54–60.
  56. Li B, Sun A, Youn H, Hong Y, Terranova PF, Thrasher JB, Xu P, Spencer D: Conditional Akt activation promotes androgen-independent progression of prostate cancer. Carcinogenesis 2007;28:572–583.
  57. Tamburini J, Elie C, Bardet V, Chapuis N, Park S, Broët P, Cornillet-Lefebvre P, Lioure B, Ugo V, Blanchet O, Ifrah N, Witz F, Dreyfus F, Mayeux P, Lacombe C, Bouscary D: Constitutive phosphoinositide 3-kinase/Akt activation represents a favorable prognostic factor in de novo acute myelogenous leukemia patients. Blood 2007;110:1025–1028.
  58. Zeng Z, Sarbassov dos D, Samudio IJ, Yee KW, Munsell MF, Ellen Jackson C, Giles FJ, Sabatini DM, Andreeff M, Konopleva M: Rapamycin derivatives reduce mTORC2 signaling and inhibit AKT activation in AML. Blood 2007;109:3509–3512.
  59. O’Reilly KE, Rojo F, She QB, Solit D, Mills GB, Smith D, Lane H, Hofmann F, Hicklin DJ, Ludwig DL, Baselga J, Rosen N: mTOR inhibition induces upstream receptor tyrosine kinase signaling and activates Akt. Cancer Res 2006;66:1500–1508.
  60. Alessi DR, Cohen P: Mechanism of activation and function of protein kinase B. Curr Opin Genet Dev 1998;8:55–62.
  61. Barragán M, de Frias M, Iglesias-Serret D, Campàs C, Castaño E, Santidrián AF, Coll-Mulet L, Cosialls AM, Domingo A, Pons G, Gil J: Regulation of Akt/PKB by phosphatidylinositol 3-kinase-dependent and -independent pathways in B-cell chronic lymphocytic leukemia cells: role of protein kinase C beta. J Leukoc Biol 2006;80:1473–1479.
  62. Luo J, Manning BD, Cantley LC: Targeting the PI3K-Akt pathway in human cancer: rationale and promise. Cancer Cell 2003;4:257–262.
  63. Woodgett JR: Recent advances in the protein kinase B signaling pathway. Curr Opin Cell Biol 2005;17:150–157.
  64. Theodoropoulou M, Zhang J, Laupheimer S, Paez-Pereda M, Erneux C, Florio T, Pagotto U, Stalla GK: Octreotide, a somatostatin analogue, mediates its antiproliferative action in pituitary tumor cells by altering phosphatidylinositol 3-kinase signaling and inducing Zac1 expression. Cancer Res 2006;66:1576–1582.
  65. Burnett PE, Barrow RK, Cohen NA, Snyder SH, Sabatini DM: RAFT1 phosphorylation of the translational regulators p70 S6 kinase and 4E-BP1. Proc Natl Acad Sci USA 1998;95:1432–1437.
  66. Weng QP, Kozlowski M, Belham C, Zhang A, Comb MJ, Avruch J: Regulation of the p70 S6 kinase by phosphorylation in vivo. Analysis using site-specific anti-phosphopeptide antibodies. J Biol Chem 1998;273:16621–16629.
  67. Pullen N, Thomas G: The modular phosphorylation and activation of p70s6k. FEBS Lett 1997;410:78–82.
  68. Pullen N, Dennis PB, Andjelkovic M, Dufner A, Kozma SC, Hemmings BA, Thomas G: Phosphorylation and activation of p70s6k by PDK1. Science 1998;279:707–710.
  69. Huang S, Houghton PJ: Targeting mTOR signaling for cancer therapy. Curr Opin Pharmacol 2003;3:371–377.
  70. Navé BT, Ouwens M, Withers DJ, Alessi DR, Shepherd PR: Mammalian target of rapamycin is a direct target for protein kinase B: identification of a convergence point for opposing effects of insulin and amino acid deficiency on protein translation. Biochem J 1999;344(Pt 2):427–431.
  71. Peterson RT, Beal PA, Comb MJ, Schreiber SL: FKBP12-rapamycin-associated protein (FRAP) autophosphorylates at serine 2481 under translationally repressive conditions. J Biol Chem 2000;275:7416–7423.
  72. Inoki K, Li Y, Zhu T, Wu J, Guan KL: TSC2 is phosphorylated and inhibited by Akt and suppresses mTOR signalling. Nat Cell Biol 2002;4:648–657.
  73. Li Y, Corradetti MN, Inoki K, Guan KL: TSC2: filling the GAP in the mTOR signaling pathway. Trends Biochem Sci 2004;29:32–38.
  74. Naegele S, Morley SJ: Molecular cross-talk between MEK1/2 and mTOR signaling during recovery of 293 cells from hypertonic stress. J Biol Chem 2004;279:46023–46034.
  75. Ballif BA, Roux PP, Gerber SA, MacKeigan JP, Blenis J, Gygi SP: Quantitative phosphorylation profiling of the ERK/p90 ribosomal S6 kinase-signaling cassette and its targets, the tuberous sclerosis tumor suppressors. Proc Natl Acad Sci U S A 2005;102:667–672.
  76. Inoki K, Ouyang H, Zhu T, Lindvall C, Wang Y, Zhang X, Yang Q, Bennett C, Harada Y, Stankunas K, Wang CY, He X, MacDougald OA, You M, Williams BO, Guan KL: TSC2 integrates Wnt and energy signals via a coordinated phosphorylation by AMPK and GSK3 to regulate cell growth. Cell 2006;126:955–968.
  77. Ma L, Chen Z, Erdjument-Bromage H, Tempst P, Pandolfi PP: Phosphorylation and functional inactivation of TSC2 by Erk: implications for tuberous sclerosis and cancer pathogenesis. Cell 2005;121:179–193.
  78. Buscail L, Delesque N, Estève 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 U S A 1994;91:2315–2319.
  79. Liebow C, Reilly C, Serrano M, Schally AV: Somatostatin analogues inhibit growth of pancreatic cancer by stimulating tyrosine phosphatase. Proc Natl Acad Sci USA 1989;86:2003–2007.


Pay-per-View Options
Direct payment This item at the regular price: USD 38.00
Payment from account With a Karger Pay-per-View account (down payment USD 150) you profit from a special rate for this and other single items.
This item at the discounted price: USD 26.50