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Ketcham JM, Haling J, Khare S, Bowcut V, Briere DM, Burns AC, Gunn RJ, Ivetac A, Kuehler J, Kulyk S, Laguer J, Lawson JD, Moya K, Nguyen N, Rahbaek L, Saechao B, Smith CR, Sudhakar N, Thomas NC, Vegar L, Vanderpool D, Wang X, Yan L, Olson P, Christensen JG, Marx MA. Design and Discovery of MRTX0902, a Potent, Selective, Brain-Penetrant, and Orally Bioavailable Inhibitor of the SOS1:KRAS Protein-Protein Interaction. J Med Chem 2022; 65:9678-9690. [PMID: 35833726 PMCID: PMC9340770 DOI: 10.1021/acs.jmedchem.2c00741] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
SOS1 is one of the major guanine nucleotide exchange
factors that
regulates the ability of KRAS to cycle through its “on”
and “off” states. Disrupting the SOS1:KRASG12C protein–protein interaction (PPI) can increase the proportion
of GDP-loaded KRASG12C, providing a strong mechanistic
rationale for combining inhibitors of the SOS1:KRAS complex with inhibitors
like MRTX849 that target GDP-loaded KRASG12C. In this report,
we detail the design and discovery of MRTX0902—a potent, selective,
brain-penetrant, and orally bioavailable SOS1 binder that disrupts
the SOS1:KRASG12C PPI. Oral administration of MRTX0902
in combination with MRTX849 results in a significant increase in antitumor
activity relative to that of either single agent, including tumor
regressions in a subset of animals in the MIA PaCa-2 tumor mouse xenograft
model.
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Affiliation(s)
- John M Ketcham
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Jacob Haling
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Shilpi Khare
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Vickie Bowcut
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - David M Briere
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Aaron C Burns
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Robin J Gunn
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Anthony Ivetac
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Jon Kuehler
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Svitlana Kulyk
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Jade Laguer
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - J David Lawson
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Krystal Moya
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Natalie Nguyen
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Lisa Rahbaek
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Barbara Saechao
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Christopher R Smith
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Niranjan Sudhakar
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Nicole C Thomas
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Laura Vegar
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Darin Vanderpool
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Xiaolun Wang
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Larry Yan
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Peter Olson
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - James G Christensen
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
| | - Matthew A Marx
- Mirati Therapeutics, 3545 Cray Court, San Diego, California 92121, United States
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2
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Role of protein S-Glutathionylation in cancer progression and development of resistance to anti-cancer drugs. Arch Biochem Biophys 2021; 704:108890. [PMID: 33894196 DOI: 10.1016/j.abb.2021.108890] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022]
Abstract
The survival, functioning and proliferation of mammalian cells are highly dependent on the cellular response and adaptation to changes in their redox environment. Cancer cells often live in an altered redox environment due to aberrant neo-vasculature, metabolic reprogramming and dysregulated proliferation. Thus, redox adaptations are critical for their survival. Glutathione plays an essential role in maintaining redox homeostasis inside the cells by binding to redox-sensitive cysteine residues in proteins by a process called S-glutathionylation. S-Glutathionylation not only protects the labile cysteine residues from oxidation, but also serves as a sensor of redox status, and acts as a signal for stimulation of downstream processes and adaptive responses to ensure redox equilibrium. The present review aims to provide an updated overview of the role of the unique redox adaptations during carcinogenesis and cancer progression, focusing on their dependence on S-glutathionylation of specific redox-sensitive proteins involved in a wide range of processes including signalling, transcription, structural maintenance, mitochondrial functions, apoptosis and protein recycling. We also provide insights into the role of S-glutathionylation in the development of resistance to chemotherapy. Finally, we provide a strong rationale for the development of redox targeting drugs for treatment of refractory/resistant cancers.
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3
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Laskar RS, Ghosh SK, Talukdar FR. Rectal cancer profiling identifies distinct subtypes in India based on age at onset, genetic, epigenetic and clinicopathological characteristics. Mol Carcinog 2014; 54:1786-95. [PMID: 25418895 DOI: 10.1002/mc.22250] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 09/26/2014] [Accepted: 10/10/2014] [Indexed: 01/13/2023]
Abstract
Rectal cancer is a heterogeneous disease that develops through multiple pathways characterized by genetic and epigenetic alterations. India has a comparatively higher proportion of rectal cancers and early-onset cases. We analyzed genetic (KRAS, TP53 and BRAF mutations, and MSI), epigenetic alterations (CpG island methylation detection of 10 tumor-related genes/loci), the associated clinicopathological features and survival trend in 80 primary rectal cancer patients from India. MSI was detected using BAT 25 and BAT 26 mononucleotide markers and mutation of KRAS, TP53, and BRAF V600E was detected by direct sequencing. Methyl specific polymerase chain reaction was used to determine promoter methylation status of the classic CIMP panel markers (P16, hMLH1, MINT1, MINT2, and MINT31) as well as other tumor specific genes (DAPK, RASSF1, BRCA1, and GSTP1). MSI and BRAF mutations were uncommon but high frequencies of overall KRAS mutations (67.5%); low KRAS codon 12 and a novel KRAS G15S mutation with concomitant RASSF1 methylation in early onset cases were remarkable. Hierarchical clustering as well as principal component analysis identified three distinct subgroups of patients having discrete age at onset, clinicopathological, molecular and survival characteristics: (i) a KRAS associated CIMP-high subgroup; (ii) a significantly younger MSS, CIMP low, TP53 mutant group having differential KRAS mutation patterns, and (iii) a CIMP-negative, TP53 mutated group. The early onset subgroup exhibited the most unfavorable disease characteristics with advanced stage, poorly differentiated tumors and had the poorest survival compared to the other subgroups. Genetic and epigenetic profiling of rectal cancer patients identified distinct subtypes in Indian population.
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4
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Huang MY, Liu HC, Yen LC, Chang JY, Huang JJ, Wang JY, Lin SR. Decreasing relapse in colorectal cancer patients treated with cetuximab by using the activating KRAS detection chip. Tumour Biol 2014; 35:9639-47. [PMID: 24964961 DOI: 10.1007/s13277-014-2263-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/18/2014] [Indexed: 12/20/2022] Open
Abstract
The KRAS oncogene was among the first genetic alterations in colorectal cancer (CRC) to be discovered. Moreover, KRAS somatic mutations might be used for predicting the efficiency of anti-epidermal growth factor receptor therapeutic drugs. Because the KRAS mutations are similar in the primary CRC and/or the CRC metastasis, KRAS mutation testing can be performed on both specimen types. The purpose of this study was to investigate the clinical advantage of using a KRAS pathway-associated molecule analysis chip to analyze CRC patients treated with cetuximab. Our laboratory developed a KRAS pathway-associated molecule analysis chip and a weighted enzymatic chip array (WEnCA) technique, activating KRAS detection chip, which can detect KRAS mutation status by screening circulating cancer cells in the bloodstream. We prospectively enrolled 210 stage II-III CRC patients who received adjuvant oxaliplatin plus infusional 5-fluorouracil/leucovorin (FOLFOX)-4 chemotherapy with or without cetuximab. We compared the chip results of preoperative blood specimens with disease control status in these patients. Among the 168 CRC patients with negative chip results, 119 were treated with FOLFOX-4 plus cetuximab chemotherapy, and their relapse rate was 35.3 % (42/119). In contrast, the relapse rate was 71.4 % among the patients with negative chip results who received FOLFOX-4 treatment alone (35/49). Negative chip results were significantly correlated with better treatment outcomes in the FOLFOX-4 plus cetuximab group (P < 0.001). We suggest that the activating KRAS detection chip is a potential tool for predicting clinical outcomes in CRC patients following FOLFOX-4 treatment with or without cetuximab therapy.
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Affiliation(s)
- Ming-Yii Huang
- Department of Radiation Oncology, Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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5
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Scholl C, Fröhling S, Dunn IF, Schinzel AC, Barbie DA, Kim SY, Silver SJ, Tamayo P, Wadlow RC, Ramaswamy S, Döhner K, Bullinger L, Sandy P, Boehm JS, Root DE, Jacks T, Hahn WC, Gilliland DG. Synthetic lethal interaction between oncogenic KRAS dependency and STK33 suppression in human cancer cells. Cell 2009; 137:821-34. [PMID: 19490892 DOI: 10.1016/j.cell.2009.03.017] [Citation(s) in RCA: 416] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 01/16/2009] [Accepted: 03/09/2009] [Indexed: 02/06/2023]
Abstract
An alternative to therapeutic targeting of oncogenes is to perform "synthetic lethality" screens for genes that are essential only in the context of specific cancer-causing mutations. We used high-throughput RNA interference (RNAi) to identify synthetic lethal interactions in cancer cells harboring mutant KRAS, the most commonly mutated human oncogene. We find that cells that are dependent on mutant KRAS exhibit sensitivity to suppression of the serine/threonine kinase STK33 irrespective of tissue origin, whereas STK33 is not required by KRAS-independent cells. STK33 promotes cancer cell viability in a kinase activity-dependent manner by regulating the suppression of mitochondrial apoptosis mediated through S6K1-induced inactivation of the death agonist BAD selectively in mutant KRAS-dependent cells. These observations identify STK33 as a target for treatment of mutant KRAS-driven cancers and demonstrate the potential of RNAi screens for discovering functional dependencies created by oncogenic mutations that may enable therapeutic intervention for cancers with "undruggable" genetic alterations.
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Affiliation(s)
- Claudia Scholl
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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6
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Akagi K, Uchibori R, Yamaguchi K, Kurosawa K, Tanaka Y, Kozu T. Characterization of a novel oncogenic K-ras mutation in colon cancer. Biochem Biophys Res Commun 2006; 352:728-32. [PMID: 17150185 DOI: 10.1016/j.bbrc.2006.11.091] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 11/15/2006] [Indexed: 12/23/2022]
Abstract
Activating mutations of RAS are frequently observed in subsets of human cancers, indicating that RAS activation is involved in tumorigenesis. Here, we identified and characterized a novel G to T transversion mutation of the K-ras gene at the third position of codon 19 (TTG) which substituted phenylalanine for leucine in 3 primary colon carcinomas. Biological and biochemical activity was examined using transformed NIH3T3 cells expressing mutant or wild-type K-ras. Transformants harboring the K-ras mutation at codon 19 showed proliferative capacity under serum-starved conditions, less contact inhibition, anchorage-independent growth, tumorigenicity in nude mice and elevation of active Ras-GTP levels. These results indicated that this novel mutation possesses high oncogenic activity.
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Affiliation(s)
- Kiwamu Akagi
- Molecular Diagnosis and Cancer Prevention Division, Saitama Cancer Center, 818 Komuro Ina, Kitaadachigun, Saitama 362-0806, Japan.
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7
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Chen YF, Wang JY, Wu CH, Chen FM, Cheng TL, Lin SR. Detection of circulating cancer cells with K-ras oncogene using membrane array. Cancer Lett 2005; 229:115-22. [PMID: 16157223 DOI: 10.1016/j.canlet.2004.12.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 12/10/2004] [Accepted: 12/13/2004] [Indexed: 11/23/2022]
Abstract
K-ras oncogene is frequently found in human cancers and thus may serve as a potential diagnostic marker for cancer cells in circulation. So far, there is no reliable method for detecting cancer cells with K-ras oncogene in peripheral blood. The objective of this study was to develop a diagnostic membrane array using activated K-ras oncogene-associated molecules as detection targets. In our previous study, cDNA microarray analysis showed that there were 94 genes differentially expressed in K-ras mutant stably transfected adrenocortical cells. In the present study, we obtained 22 up-regulated genes in the closest relation to K-ras oncogene through bioinformatic analysis. At first, we carried out membrane array analysis by using in vitro culture cells. We demonstrated that this diagnostic technique was feasible and highly sensitive. A number as low as 5 cancer cells bearing K-ras oncogene in 1 ml of blood could be distinctively detected. Then, we collected blood specimens from 76 cancer patients. Direct sequencing analysis of these 76 samples showed that K-ras mutation was present in 43 patients with mutation sites mainly at codons 13, 15 and 61, which have been commonly established to be activated sites. We subsequently analyzed these 76 specimens with our diagnostic membrane array. Thirty-nine specimens were detected as positive for activated K-ras oncogene. Eighty percent (12/15) of mutations occurred at codon 13, 72.7% (8/11) at codon 61, and 88.9% (8/9) at codon 15 were accurately detected by our diagnostic membrane. Finally, through a series of biostatistical analyses, the sensitivity, specificity and accuracy of the diagnostic membrane array were 83.7, 90.9 and 86.8%, respectively. These findings suggest that the K-ras oncogene membrane array has a great potential for further investigation and clinical application.
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Affiliation(s)
- Y-F Chen
- MedicoGenomic Research Center, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Rd, Kaohsiung 80317, Taiwan, ROC
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8
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Wang JY, Hsieh JS, Chen FM, Yeh CS, Alexandersen K, Huang TJ, Chen DCP, Lin SR. High frequency of activated K-ras codon 15 mutant in colorectal carcinomas from Taiwanese patients. Int J Cancer 2003; 107:387-93. [PMID: 14506738 DOI: 10.1002/ijc.11417] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Colorectal carcinogenesis is regarded as a multistep process resulting from accumulation of genetic alterations, including activation of protooncogenes and inactivation of tumor suppressor genes via signal transduction trigger the stage-wise progression to malignancy. The reported incidence of K-ras mutation detected in general tissue samples ranges from 21-60% in primary colorectal cancers (CRC). To assess the prevalence and spectrum of K-ras mutations in Taiwanese patients with CRC, we analyzed 65 CRC patients by polymerase chain reaction-single strand conformation polymorphism analysis, followed by direct sequencing. K-ras mutations were detected in 43.1% (28 of 65) of the tumors. The mutational hot spots were located at codons 12, 13, 15 and 20, especially with the highest frequency at codon 15. To understand whether the codon 15 mutations in CRC were associated with activation of K-ras oncogene and the alterations of its biocharacteristics, mutant K-ras genes were cloned from tumor tissues and then inserted into expression vector pBKCMV to construct the prokaryotic expression plasmid pK15MCMV. Mutant K-ras genes were expressed at high levels in E. coli and the mutant K-ras proteins were shown to be functional with respect to their well-known specific, high-affinity, GDP/GTP binding. The purified K-ras protein from E. coli was then measured for its intrinsic GTPase activity and the extrinsic GTPase activity in the presence of GTPase-activating protein for ras. We found that the extrinsic GTPase activity of the codon 15 mutant K-ras proteins (p21(K-ras15M)) in the presence of GAP is much lower than that of the wild-type K-ras protein (p21 BN), whereas the intrinsic GTPase activity is nearly the same as that of the wild-type K-ras protein. The results indicated that mutation at the codon 15 of K-ras gene indeed decreased GTPase activity in CRC, however, its association with tumorigenesis of CRC needs be clarified by further studies.
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Affiliation(s)
- Jaw-Yuan Wang
- Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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9
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Morgan MA, Ganser A, Reuter CWM. Therapeutic efficacy of prenylation inhibitors in the treatment of myeloid leukemia. Leukemia 2003; 17:1482-98. [PMID: 12886235 DOI: 10.1038/sj.leu.2403024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Farnesyltransferase inhibitors (FTIs) represent a new class of anticancer agents that specifically target post-translational farnesylation of various proteins that mediate several cellular processes such as signal transduction, growth, differentiation, angiogenesis and apoptosis. These compounds were originally designed to block oncogenic RAS-induced tumor growth by impeding RAS localization to the membrane, but it is now evident that FTIs also affect processing of several other proteins. The need for novel therapies in myeloid leukemia is underscored by the high rate of treatment failure due to high incidences of relapse- and treatment-related toxicities. As RAS deregulation is important in the pathogenesis of myeloid leukemias, targeting of RAS signaling may provide a new therapeutic strategy. Several FTIs (eg BMS-214662, L-778,123, R-115777 and SCH66336) have entered phase I and phase II clinical trials in myeloid leukemias. This review discusses recent clinical results, potential combination therapies, mechanisms of resistance and the clinical challenges of toxicities associated with prenylation inhibitors.
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Affiliation(s)
- M A Morgan
- Department of Hematology and Oncology, Hannover Medical School, Hannover, Germany
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10
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Wu CH, Chen YF, Wang JY, Hsieh MC, Yeh CS, Lian ST, Shin SJ, Lin SR. Mutant K-ras oncogene regulates steroidogenesis of normal human adrenocortical cells by the RAF-MEK-MAPK pathway. Br J Cancer 2002; 87:1000-5. [PMID: 12434292 PMCID: PMC2364317 DOI: 10.1038/sj.bjc.6600589] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2002] [Accepted: 08/14/2002] [Indexed: 01/27/2023] Open
Abstract
The result of our previous study has shown that the K-ras mutant (pK568MRSV) transfected human adrenocortical cells can significantly increase cortisol production and independently cause cell transformation. The aim of this study is to investigate the effect of the active K-ras oncogene on the cortisol production in normal human adrenocortical cells. First we used isopropyl thiogalactoside to induce the inducible mutant K-ras expression plasmid, pK568MRSV, in the stable transfected human adrenocortical cells. The result showed that the increase of RasGTP levels in transfected cells was time-dependent after isopropyl thiogalactoside induction. Additionally, results from Western blot analysis revealed significant elevation in phosphorylation of c-Raf-1 and Mitogen-activated protein kinase. We also detected the levels of mRNA encoding Cholesterol side-chain cleavage enzyme (P450(SCC)), 17alpha-Hydroxylase/17,20-lyase (P450(c17)) and 3beta-Hydroxysteroid dehydrogenase (3betaHSD) were increased in human adrenocortical cells transfected with mutant K-ras after IPTG treatment. The increase of mRNA amount in P450(scc) P450(c17) and 3betaHSD and the elevation of cortisol level were inhibited with a pretreatment of PD098059, a specific extracellular signal-regulated kinase inhibitor. In our previous report, we proved that lovastatin, a pharmacological inhibitor of p21(ras) function, also reversed the increase of cortisol level in mutant K-ras stably transfected human adrenocortical cells. Taken together, these findings proved that the active mutant Ras enhanced not only cell proliferation but also steroidogenesis in steroidogenic phenotype cells by activating Raf-MEK-MAPK related signal transduction pathway. Therefore, we believe that K-ras mutants influence regulation of steroidogenesis in adrenocortical cells through RAF-MEK-MAPK pathway.
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Affiliation(s)
- C-H Wu
- Graduate Institute of Medicine, Kaohsiung Medical University Kaohsiung, 80317, Taiwan
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11
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Abstract
The adrenal glands are a major source of steroid hormone biosynthesis. In normal physiology, the pituitary hormone corticotropin (ACTH) regulates the secretion of glucocorticoids via its G protein-coupled receptor (ACTHR), the product of the MC2R gene. Aldosterone is another major product of the adrenal gland; its regulation is controlled mainly by the renin-angiotensin system, although ACTH plays a role, too, especially under certain pathological conditions. The adrenal gland also secretes lesser amounts of androgens and intermediate metabolites of all these steroids. Unregulated secretion of any of these hormones can be caused by tumors, adrenocortical adenomas or carcinomas, and/or bilateral (or, rarely, unilateral) hyperplasia. Cortisol-producing hyperplasia of the adrenal glands is caused by two distinct syndromes, both of which have been directly or indirectly associated with protein kinase A signaling: (i) primary pigmented nodular adrenocortical disease (PPNAD) (a micronodular form of bilateral adrenal hyperplasia), either isolated (rarely) or in the context of Carney complex, is caused (in most cases) by mutations of the PRKAR1A gene; and (ii) ACTH-independent macronodular adrenal hyperplasia (AIMAH), or massive macronodular adrenal disease (MMAD), has been associated with aberrant (ectopic) expression, and presumably regulation, of various G protein-coupled receptors. AIMAH is a rare, sporadic condition affecting predominantly middle-aged men and women with an almost equal ratio (the latter in contrast to other forms of endogenous Cushing's syndrome). Some familial cases of AIMAH have also been described, and it appears that the pathophysiological phenomena underlying AIMAH may be present in the far more common, sporadic adrenocortical tumors and, perhaps, in the nodular growth detected in the adrenal glands of the elderly in the general population. Thus, the study of ectopic receptor expression and cAMP-dependent PKA activity in AIMAH may have wider implications for adrenal and, indeed, endocrine tumorigenesis.
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Affiliation(s)
- Isabelle Bourdeau
- Unit on Genetics and Endocrinology, Developmental Endocrinology Branch, National Institute of Child Health and Human Development, Bethesda, Maryland 20892-1862, USA
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12
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Abstract
Adrenocortical carcinoma is a rare tumor that carries a very poor prognosis. Despite efforts to develop new therapeutic regimens to treat this disease, surgery remains the mainstay of treatment. Laboratory studies of adrenocortical cancers have revealed a wide variety of signaling pathways that can be altered in these neoplasms. Although ACTH signaling through adenylyl cyclase and protein kinase A is important for normal adrenal cellular physiology, there is evidence to suggest that this pathway may inhibit the growth of adrenocortical tumors, and that inactivation of the ACTH receptor may promote tumor formation. Although multiple signal transduction pathways are essential for normal adrenal growth and hormone secretion, efforts to identify events required for neoplastic transformation have met with limited success. Alterations that have frequently been observed in adrenocortical carcinoma include up-regulation of the IGF-II system, as well as mutations in TP53 and RAS. Current studies aim to elucidate the mechanisms of tumor growth by studying proproliferative signaling pathways, such as those involving Akt/PKB and the mitogen-activated protein kinases (MAPKs). Although studies of single pathways have been helpful in guiding investigations, new tools to study the integration and multiplicity of signaling pathways hold the hope of improved understanding of the signaling pathway alterations in adrenocortical cancer.
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Affiliation(s)
- Lawrence S Kirschner
- Unit on Genetics and Endocrinology, DEB, NICHD, National Instutes of Health, Bethesda, Maryland 20892-1862, USA
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13
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Peri A, Luciani P, Conforti B, Baglioni-Peri S, Cioppi F, Crescioli C, Ferruzzi P, Gelmini S, Arnaldi G, Nesi G, Serio M, Mantero F, Mannelli M. Variable expression of the transcription factors cAMP response element-binding protein and inducible cAMP early repressor in the normal adrenal cortex and in adrenocortical adenomas and carcinomas. J Clin Endocrinol Metab 2001; 86:5443-9. [PMID: 11701720 DOI: 10.1210/jcem.86.11.8042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The molecular mechanisms leading to adrenocortical tumorigenesis have been only partially elucidated so far. Because the pituitary hormone ACTH, via activation of the cAMP pathway, regulates both cell proliferation/differentiation and steroid synthesis in the adrenal cortex, in this study we focused on the cAMP-dependent transcription factors cAMP responsive element modulator (CREM) and cAMP responsive element binding protein (CREB). We studied CREM and CREB expression by RT-PCR in human normal adrenal cortex (n = 3), adrenocortical adenomas (n = 8), and carcinomas (n = 8). We found transcripts corresponding to the isoforms alpha, beta, gamma, and tau2 of the CREM gene in all of the normal adrenal tissues, in the adenomas, and in seven of eight carcinomas. On the other hand, mRNA for the inducible cAMP early repressor isoforms, which derive from an internal promoter of CREM gene, was detected in the normal adrenal and in seven of eight adenomas, but in only three of eight carcinomas. Similarly, CREB transcripts were readily detectable in all normal adrenals and adenomas, whereas they were not found in four of eight adrenal carcinomas. To further characterize the carcinomas, telomerase activity and the expression of the ACTH receptor gene were determined. Telomerase activity in the carcinomas resulted in levels significantly higher than in the adenomas, whereas the levels of ACTH receptor mRNA were lower in the carcinomas. No correlation was found in the carcinomas between the levels of the ACTH receptor transcript and the loss of expression of CREB/inducible cAMP early repressor, suggesting that this alteration is not secondary to an upstream disregulation at the receptor level. In conclusion, our results suggest that an alteration in cAMP signaling may be associated with malignancies of the adrenal cortex.
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Affiliation(s)
- A Peri
- Endocrine Unit, Department of Clinical Physiopathology, University of Florence, 50139 Florence, Italy
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14
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Morgan MA, Dolp O, Reuter CW. Cell-cycle-dependent activation of mitogen-activated protein kinase kinase (MEK-1/2) in myeloid leukemia cell lines and induction of growth inhibition and apoptosis by inhibitors of RAS signaling. Blood 2001; 97:1823-34. [PMID: 11238126 DOI: 10.1182/blood.v97.6.1823] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Disruption of the RAS-to-mitogen-activated protein kinase (MAPK/ERK) signaling pathway, either directly through activating RAS gene mutations or indirectly through other genetic aberrations, plays an important role in the molecular pathogenesis of myeloid leukemias. Constitutive activation of ERK-1/2 and MEK-1/2, which elicit oncogenic transformation in fibroblasts, has recently been observed in acute myeloid leukemias (AML). In this study, the activation of the RAS-to-MAPK cascade in 14 AML and 5 chronic myeloid leukemia (CML) cell lines is examined and correlated with the effects of a panel of 9 RAS signaling inhibitors on cell viability, colony formation, cell-cycle progression, and induction of apoptosis. Activation of MEK, ERK, and the transcription factors CREB-1, ATF-1, and c-Myc is demonstrated in the majority of the cell lines (9 of 14 AML and 2 of 5 CML cell lines). Although activation of the ERK cascade did not always correlate with the presence of activating RAS mutations or BCR-Abl, it is linked to the G0/G1 and the G2/M phase of the cell cycle. In contrast to most inhibitors (eg, B581, Cys-4-Abs-Met, FPT-2, FTI-276, and FTS), a significant growth inhibition was only observed for FTI-277 (19 of 19), FPT-3 (10 of 19), and the MEK inhibitors U0126 (19 of 19) and PD098059 (8 of 19). Treatment of NB-4 cells with FTI-277 primarily resulted in a G2/M block, whereas treatment with FPT-3 and U0126 led to induction of apoptosis. FTI-277 revealed strong toxicity toward normal purified CD34+ cells. The results suggest differences in the mechanisms of action and support a potential therapeutic usefulness of these inhibitors in the treatment of myeloid leukemias.
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Affiliation(s)
- M A Morgan
- Department of Hematology and Oncology, Section Molecular Biology, University of Ulm, Germany
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