Inhibition of Human Adrenocortical Cancer Cell Growth by Temozolomide in Vitro and the Role of the MGMT Gene.
Treatment of patients with adrenocortical carcinomas (ACC) with mitotane and/or chemotherapy is often associated with toxicity and poor tumor response. New therapeutic options are urgently needed.



The objectives of the study were to evaluate the therapeutic possibilities of temozolomide (TMZ) in ACC cells and to assess the potential predictive role of the DNA repair gene O6-Methylguanine-DNA methyltransferase (MGMT) in adrenocortical tumors.



Three human ACC cell lines and eight primary ACC cultures were used to assess effects of TMZ in vitro. In the cell lines, 11 normal adrenals, 16 adrenocortical adenomas, and 29 ACC, MGMT promoter methylation and expression were determined.



IC50values of TMZ on cell growth were 39 μM, 38 μM, and 44 μM for H295R, HAC15, and SW13, respectively. TMZ induced apoptosis and provoked cytotoxic and cytostatic effects by reducing the surviving fraction of ACC colonies and the colony size. TMZ thereby induced cell cycle arrests in ACC cell lines. TMZ and mitotane both inhibited growth of ACC cells cultured as three-dimensional spheroids. TMZ inhibited cell amount in five of eight primary ACC cultures and induced apoptosis in seven of eight primary ACC cultures. In ACC cell lines and adrenal tissues, MGMT promoter methylation was low. In ACCs, methylation was inversely correlated with MGMT mRNA expression. MGMT protein expression was not correlated with MGMT methylation.



For the first time, we show the therapeutic potential of temozolomide for ACC, offering an urgently needed potential alternative for patients not responding to mitotane alone or with etoposide, doxorubicin, and cisplatin. (Pre-)clinical studies are warranted to assess efficacy in vivo.
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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Creemers
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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PM
van Koetsveld
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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van den Dungen
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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Korpershoek
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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FJ
van Kemenade
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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GJ
Franssen
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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de Herder
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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Feelders
Department of Internal Medicine, Division of Endocrinology (S.G.C., P.M.v.K., E.S.R.v.d.D., W.W.d.H., R.A.F., L.J.H.), and Departments of Pathology (E.K., F.J.v.K.) and Surgery (G.J.H.F.), Erasmus University Medical Center, 3015 CE Rotterdam, The Netherlands.
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LJ
Hofland
D000293:Adolescent; D000306:Adrenal Cortex Neoplasms / Q000188:drug therapy*; D018268:Adrenocortical Carcinoma / Q000188:drug therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D045744:Cell Line, Tumor; D002648:Child; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000378:metabolism*; D045643:DNA Repair Enzymes / Q000378:metabolism*; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008939:Mitotane / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D000077204:Temozolomide; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D055815:Young Adult
D018906:Antineoplastic Agents, Alkylating; D018931:Antineoplastic Agents, Hormonal; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D008939:Mitotane; D003606:Dacarbazine; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D045643:DNA Repair Enzymes; D000077204:Temozolomide