title: Biological evaluation of MR36, a novel non-polyglutamatable thymidylate synthase inhibitor that blocks cell cycle progression in melanoma cell lines.
abstract: Melanoma is one of the most common cancers, and its incidence has continued to increase over the past few decades. Chemotherapy resistance and related defects in apoptotic signaling are critical for the high mortality of melanoma. Effective drugs are lacking because apoptosis regulation in this tumor type is not well understood. The folate pathway has been considered an interesting target for anticancer therapies, and approaches targeting this pathway have recently been extended to melanoma treatment. In this study, the intracellular apoptosis signaling pathways of two melanoma cells lines (SK-MEL-2 and SK-MEL-28) were investigated after treatment with a new experimental antifolate substance (MR36) that targets thymidylate synthase. In both melanoma cell lines, apoptosis induction was triggered by a p53-independent mechanism. MR36-induced apoptosis was associated with a loss of both mitochondrial membrane potential and caspase-3 activation. Induction of cell cycle arrest by MR36 was associated with changes in the expression of key cell cycle regulators, such as p21 and cyclin D1, and the hypophosphorylation of pRb. In addition, Fas signaling was also analyzed. These findings suggest that, unlike classical antifolates, MR36 exerted an inhibitory effect on both the enzymatic function and expression of thymidylate synthase, thereby inducing apoptosis through the activation of the extrinsic and intrinsic pathways in the melanoma cell lines. MR36 showed a different mechanism of action from the known antifolates (Nolatrexed and Pemetrexed) that resulted in higher anticancer activity. Therefore, MR36 should be included as a potential new therapeutic treatment in melanoma research.
authors: Department of Dermatology, University of Modena and Reggio Emilia, Via del Pozzo, 71-41126 Modena, Italy.
authors: Stefania
authors: S
authors: Giudice
authors: Luisa
authors: L
authors: Benassi
authors: Giorgia
authors: G
authors: Bertazzoni
authors: Eugenia
authors: E
authors: Veratti
authors: Daria
authors: D
authors: Morini
authors: Paola
authors: P
authors: Azzoni
authors: Maria P
authors: MP
authors: Costi
authors: Alberto
authors: A
authors: Venturelli
authors: Silvia
authors: S
authors: Pirondi
authors: Stefania
authors: S
authors: Seidenari
authors: Cristina
authors: C
authors: Magnoni
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects* / Q000235:genetics; D045744:Cell Line, Tumor; D003374:Coumarins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D019938:Cyclin D1 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D005493:Folic Acid Antagonists / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008545:Melanoma / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D008954:Models, Biological; D010766:Phosphorylation / Q000187:drug effects; D011099:Polyglutamic Acid / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013940:Thymidylate Synthase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D003374:Coumarins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004791:Enzyme Inhibitors; D005493:Folic Acid Antagonists; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1; D011099:Polyglutamic Acid; D013940:Thymidylate Synthase; D053148:Caspase 3