Bedeutung des Tumorsuppressors PTEN für das Nierenzellkarzinom

Zusammenfassung

Fragestellung: Das Tumorsuppressorgen PTEN (phosphatase and tensin homologue deleted from chromosome 10) kodiert für eine dual-spezifische Protein- und Phospholipid-Phosphatase, die regulatorisch in Zellproliferation, Apoptose und Zellmigration eingreift. Wir haben die Expression des PTEN-Proteins in der Tumorgenese des Nierenzellkarzinoms untersucht. Material und Methode: In 42 klarzelligen Nierenzellkarzinomen (NZK) und Onkozytomen sowie in dem gesunden Nierengewebe derselben Patienten wurde die Expression des PTEN-Proteins in Westernblot-Analysen untersucht. Die zelluläre Lokalisation von PTEN wurde immunhistochemisch analysiert. Ergebnisse: PTEN war in allen untersuchten gesunden Nierengewebeproben hoch exprimiert. Die immunhistochemischen Analysen zeigten, dass fast ausschließlich proximale Tubulus-Epithelzellen, die Vorläuferzellen der klarzelligen NZKs, PTEN-positiv waren. Innerhalb der proximalen Tubulus-Epithelzellen zeigte PTEN eine deutliche Assoziation mit der Zytoplasma-Membran. In klarzelligen NZKs war die PTEN-Expression, ermittelt im Westernblot, auf 10 % der Werte des gesunden Nierengewebes reduziert (p < 0,001). Diese Reduktion war bei Frauen drastischer als bei Männern (p = 0,006). Der Grad der Reduktion entsprach in hoch differenzierten (G1) Karzinomen dem in weniger differenzierten (G2 - G4) Karzinomen. Diese Beobachtung wurde durch die immunhistochemischen Studien bestätigt. Zudem zeigte sich, dass die Membran-Assoziation von PTEN in klarzelligen NZKs nicht mehr zu beobachten war. Im Gegensatz zu den PTEN-positiven proximalen Tubulus-Epithelzellen exprimierten die distalen Tubulus-Epithelzellen, aus denen sich die gutartigen Onkozytome entwickeln, PTEN nur sehr schwach. Verglichen mit den distalen Tubulus-Epithelzellen war keine Herunterregulation von PTEN in Onkozytomen zu beobachten. Schlussfolgerung: Während der frühen Karzinogenese des Nierenzellkarzinoms geht die PTEN-Expression und die Membran-Lokalisation von PTEN verloren, so dass PTEN als Tumormarker für das NZK herangezogen werden kann.

Abstract

Purpose: PTEN (phosphatase and tensin homologue deleted from chromosome 10) is a tumor suppressor gene that encodes a dual specific protein and phospholipid phosphatase. It affects cell proliferation, apoptosis and migration. In the present study we examined protein expression of PTEN in renal carcinogenesis. Materials and Methods: In 42 clear cell renal cell carcinomas (ccRCC) and oncocytomas as well as in the corresponding normal renal tissue of the same patients, PTEN protein levels were examined using Western blot analysis. Cellular localization was analysed by immunohistochemistry. Results: Western blot analysis showed a high expression of PTEN in all investigated normal renal tissue specimens. An almost exclusive staining of proximal tubulus epithelial cells known to be precursor cells of ccRCC was observed immunohistochemically. Within the proximal tubulus cells, PTEN showed clear membrane localization. In ccRCCs, PTEN expression was markedly reduced to an average of less than 10 % compared with normal tissue as evidenced by Western blot analysis (p < 0.001). In RCCs of females, PTEN expression was more strongly reduced compared to males (p = 0.006). The degree of reduction was similar in both highly differentiated (G1) carcinomas and in less differentiated (G2 - G4) carcinomas. These observations were confirmed by immunohistochemical studies, which revealed a loss of the characteristic membrane-predominant immunostaining pattern in ccRCC. In contrast to the PTEN-positive proximal tubulus epithelial cells, the distal tubulus epithelial cells that develop into benign oncocytomas showed only very weak PTEN expression. Compared to the distal tubulus epithelial cells, no down-regulation of PTEN was seen in oncocytomas. Conclusion: We conclude that PTEN expression and PTEN membrane localization are lost during early renal cell carcinogenesis and may therefore be a valuable RCC tumor marker.

Schlüsselwörter

Nierenzellkarzinom - PTEN - proximale Tubulus-Epithelzellen

Key words

carcinoma - renal cell - PTEN - epithelial cell

Literatur

• 1 Wary K K, Mariotti A, Zurzolo C, Giancotti F G. A requirement for caveolin-1 and associated kinase Fyn in integrin signaling and anchorage-dependent cell growth.  Cell. 1998;  94 625-634
• 2 Gu J, Tamura M, Yamada K M. Tumor suppressor PTEN inhibits integrin- and growth factor-mediated mitogen-activated protein (MAP) kinase signaling pathways.  J Cell Biol. 1998;  143 1375-1383
• 3 Vuori K, Ruoslahti E. Association of insulin receptor substrate-1 with integrins.  Science. 1994;  266 1576-1578
• 4 Tamura M, Gu J, Takino T, Yamada K M. Tumor suppressor PTEN inhibition of cell invasion, migration, and growth: differential involvement of focal adhesion kinase and p130Cas.  Cancer Res. 1999;  59 442-449
• 5 Maehama T, Dixon J E. The tumor suppressor, PTEN/MMAC1, dephosphorylates the lipid second messenger, phosphatidylinositol 3,4,5-trisphosphate.  J Biol Chem. 1998;  273 13 375-13 378
• 6 Hopkin K. A surprising function for the PTEN tumor suppressor.  Science. 1998;  282 1027-1030
• 7 Cantley L C, Neel B G. New insights into tumor suppression: PTEN suppresses tumor formation by restraining the phosphoinositide 3-kinase/AKT pathway.  Proc Natl Acad Sci USA. 1999;  96 4240-4245
• 8 Stambolic V, Suzuki A, de la Pompa J L, Brothers G M, Mirtsos C, Sasaki T, Ruland J, Penninger J M, Siderovski D P, Mak T W. Negative regulation of PKB/Akt-dependent cell survival by the tumor suppressor PTEN.  Cell. 1998;  95 29-39
• 9 Steck P A, Pershouse M A, Jasser S A, Yung W K, Lin H, Ligon A H, Langford L A, Baumgard M L, Hattier T, Davis T, Frye C, Hu R, Swedlund B, Teng D H, Tavtigian S V. Identification of a candidate tumour suppressor gene, MMAC1, at chromosome 10q23.3 that is mutated in multiple advanced cancers.  Nat Genet. 1997;  15 356-362
• 10 Teng D H, Hu R, Lin H, Davis T, Iliev D, Frye C, Swedlund B, Hansen K L, Vinson V L, Gumpper K L, Ellis L, El Naggar A, Frazier M, Jasser S, Langford L A, Lee J, Mills G B, Pershouse M A, Pollack R E, Tornos C, Troncoso P, Yung W K, Fujii G, Berson A, Steck P A. MMAC1/PTEN mutations in primary tumor specimens and tumor cell lines.  Cancer Res. 1997;  57 5221-5225
• 11 Li J, Yen C, Liaw D, Podsypanina K, Bose S, Wang S I, Puc J, Miliaresis C, Rodgers L, McCombie R, Bigner S H, Giovanella B C, Ittmann M, Tycko B, Hibshoosh H, Wigler M H, Parsons R. PTEN, a putative protein tyrosine phosphatase gene mutated in human brain, breast, and prostate cancer.  Science. 1997;  275 1943-1947
• 12 Guldberg P, thor Straten P, Birck A, Ahrenkiel V, Kirkin A F, Zeuthen J. Disruption of the MMAC1/PTEN gene by deletion or mutation is a frequent event in malignant melanoma.  Cancer Res. 1997;  57 3660-3663
• 13 Cairns P, Evron E, Okami K, Halachmi N, Esteller M, Herman J G, Bose S, Wang S I, Parsons R, Sidransky D. Point mutation and homozygous deletion of PTEN/MMAC1 in primary bladder cancers.  Oncogene. 1998;  16 3215-3218
• 14 Alimov A, Li C, Gizatullin R, Fredriksson V, Sundelin B, Klein G, Zabarovsky E, Bergerheim U. Somatic mutation and homozygous deletion of PTEN/MMAC1 gene of 10q23 in renal cell carcinoma.  Anticancer Res. 1999;  19 3841-3846
• 15 Zhu X, Kwon C-H, Schlosshauer P W, Ellenson L-H, Baker S-J. PTEN induces G(1) cell cycle arrest and decreases cyclin D3 levels in endometrial carcinoma cells.  Cancer Res. 2001;  61 4569-4575
• 16 Sakurada A, Suzuki A, Sato M, Yamakawa H, Orikasa K, Uyeno S, Ono T, Ohuchi N, Fujimura S, Horii A. Infrequent genetic alterations of the PTEN/MMAC1 gene in Japanese patients with primary cancers of the breast, lung, pancreas, kidney, and ovary.  Jpn J Cancer Res. 1997;  88 1025-1028
• 17 Gesk S, Siebert R, Wacker H-H, Nurnberg N, Harder L, Lehman J, Kloppel G, Grote W, Stockle M, Schlegelberger B. Lack of deletions of the PTEN/MMAC1 and MXI1 loci in renal cell carcinoma by interphase cytogenetics.  Cancer Genet Cytogenet. 2000;  118 87-88
• 18 Smith P K, Krohn R I, Hermanson G T, Malia A K, Gartner F H, Provenzano M D, Fujimato E K, Golke N M, Olsen B J, Klenk D C. Measurement of protein using bicinchoninic acid.  Anal Biochem. 1985;  150 76-85
• 19 Tamura M, Gu J, Tran H, Yamada K M. PTEN gene and integrin signaling in cancer.  J Natl Cancer Inst. 1999;  91 1820-1828
• 20 Cohen C, McCue P A, Derose P B. Histogenesis of renal cell carcinoma and renal oncocytoma. An immunohistochemical study.  Cancer. 1988;  62 1946-1951
• 21 Wu Y, Dowbenko D, Spencer S, Laura R, Lee J, Gu Q, Lasky L A. Interaction of the tumor suppressor PTEN/MMAC with a PDZ domain of MAGI3, a novel membrane-associated guanylate kinase.  J Biol Chem. 2000;  275 21 477-21 485
• 22 Wu X, Hepner K, Castelino-Prabhu S, Do D, Kaye M B, Yuan X J, Wood J, Ross C, Sawyers C L, Whang Y E. Evidence for regulation of the PTEN tumor suppressor by a membrane-localized multi-PDZ domain containing scaffold protein MAGI-2.  Proc Natl Acad Sci U.S.A.. 2000;  97 4233-4238
• 23 Wang S I, Puc J, Li J, Bruce J N, Cairns P, Sidransky D, Parsons R. Somatic mutations of PTEN in glioblastoma multiforme.  Cancer Res. 1997;  57 4183-4186
• 24 Bostrom J, Cobbers J M, Wolter M, Tabatabai G, Weber R G, Lichter P, Collins V P, Reifenberger G. Mutation of the PTEN (MMAC1) tumor suppressor gene in a subset of glioblastomas but not in meningiomas with loss of chromosome arm 10q.  Cancer Res. 1998;  58 29-33
• 25 Liu W, James C D, Frederick L, Alderete B E, Jenkins R B. PTEN/MMAC1 mutations and EGFR amplification in glioblastomas.  Cancer Res. 1997;  57 5254-5257
• 26 Cairns P, Okami K, Halachmi S, Halachmi N, Esteller M, Herman J G, Jen J, Isaacs W B, Bova G S, Sidransky D. Frequent inactivation of PTEN/MMAC1 in primary prostate cancer.  Cancer Res. 1997;  57 4997-5000
• 27 Whang Y E, Wu X, Suzuki H, Reiter R E, Tran C, Vessella R L, Said J W, Isaacs W B, Sawyers C L. Inactivation of the tumor suppressor PTEN/MMAC1 in advanced human prostate cancer through loss of expression.  Proc Natl Acad Sci U.S.A.. 1998;  95 5246-5250
• 28 Risinger J I, Hayes A K, Berchuck A, Barrett J C. PTEN/MMAC1 mutations in endometrial cancers.  Cancer Res. 1997;  57 4736-4738
• 29 Tashiro H, Blazes M S, Wu R, Cho K R, Bose S, Wang S I, Li J, Parsons R, Ellenson L H. Mutations in PTEN are frequent in endometrial carcinoma but rare in other common gynecological malignancies.  Cancer Res. 1997;  57 3935-3940
• 30 Kondo K, Yao M, Kobayashi K, Ota S, Yoshida M, Kaneko S, Baba M, Sakai N, Kishida T, Kawakami S, Uemura H, Nagashima Y, Nakatani Y, Hosaka M. PTEN/MMAC1/TEP1 mutations in human primary renal-cell carcinomas and renal carcinoma cell lines.  Int J Cancer. 2001;  91 219-224
• 31 Kirkale Z, Yorukonglu K, Ozkara E, Kazimoglu H, Mungan U. Proliferative activity, angiogenesis and nuclear morphometry in renal cell carcinoma.  In J Urol. 2001;  8 697-703
• 32 Congregado ruiz B, Medina Lopez R A, Sanchez Gomez E, Morales Lopez A, Pascual del Pobil J L. Incidental diagnosis of renal carcinoma. Does it imply a better prognosis?.  Actas Urol Exp. 2001;  25 278-282
• 33 Elias L, Hunt W C. A literature analysis of prognostic factors for response and quality of response of patients with renal cell carcinoma to interleukin-2-based therapy.  Oncology. 2001;  61 91-101
• 34 Rasheed B K, Stenzel T T, McLendon R E, Parsons R, Friedman A H, Friedman H S, Bigner D D, Bigner S H. PTEN gene mutations are seen in high-grade but not in low-grade gliomas.  Cancer Res. 1997;  57 4187-4190