pyrimidinones and Neoplasms--Cystic--Mucinous--and-Serous

Molecular-targeted therapies have demonstrated disappointing results against most advanced solid cancers. This may largey be attributed to irrational drug use against unselected cancers. We investigated the efficacy of dual MEK-PI3K drug therapy against KRAS mutated mucin 2 (MUC2)-secreting LS174T cells and patient-derived ex vivo and in vivo models of KRAS mutated mucinous colon/appendix cancers. These tumors demonstrate unique phenotypic and genotypic features that likely predict sensitivity to this targeted co-therapy. Co-treatment with MEK inhibitor (trametinib) and PI3K inhibitor (pictilisib)-induced synergistic cytotoxicity and intrinsic mitochondrial-mediated apoptosis in LS174T cells and tumor explants in vitro. Dual drug therapy also induced endoplasmic reticulum stress (ERS)-associated proteins (GRP78/BiP, ATF4, and CHOP). However, CHOP knock-down assays demonstrated that mitochondrial-mediated apoptosis in LS174T cells was not ERS-dependent. Dual drug therapy also significantly decreased MUC2 expression, MUC2 post-translational modification (palmitoylation) and secretion in LS174T cells, suggesting a simultaneous cytotoxic and mucin suppressive mechanism of action. We also demonstrated effective mucinous tumor growth suppression in ex vivo epithelial organoid (colonoid) cultures and in in vivo intraperitoneal patient-derived xenograft models derived from mucinous colon/appendix cancer. These promising preclinical data support a role for dual MEK-PI3K inhibitor therapy in mucinous colon/appendix cancers. We postulate that mucinous KRAS mutated cancers are especially vulnerable to this co-treatment based on their unique phenotypic and genotypic characteristics.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Appendiceal Neoplasms; Appendix; Cell Line, Tumor; Chemotherapy, Adjuvant; Colon; Colonic Neoplasms; Drug Synergism; Endoplasmic Reticulum Chaperone BiP; Female; Humans; Indazoles; Intestinal Mucosa; Mice; Mitogen-Activated Protein Kinase Kinases; Molecular Targeted Therapy; Mucin-2; Mutation; Neoplasms, Cystic, Mucinous, and Serous; Phosphatidylinositol 3-Kinases; Primary Cell Culture; Protein Kinase Inhibitors; Proto-Oncogene Proteins p21(ras); Pyridones; Pyrimidinones; Sulfonamides; Xenograft Model Antitumor Assays

Low-grade serous ovarian cancer (LGSOC) constitutes 5-8% of epithelial ovarian cancers and is refractory to chemotherapy. We and others have shown metformin to cause significant growth inhibition in high-grade ovarian cancer both in vitro and in vivo. Here, we aimed to analyze if metformin was effective in inhibiting proliferation of LGSOC alone and in combination with MEK inhibitor.. Three LGSOC lines (VOA1056, VOA1312 and VOA5646) were treated with metformin, trametinib or 2-deoxyglucose (2DG) alone or in combination with metformin. Proliferation was measured by MTT assay over a period of four days. Protein expression was measured by western blotting. Seahorse Analyzer was used to measure effect of metformin on glycolysis and mitochondrial respiration.. All LGSOC cell lines showed significant inhibition with metformin in a dose- and time-dependent manner. Trametinib significantly inhibited the growth of Ras mutated LGSOC lines (VOA1312 and VOA1056), while VOA5646 cells without RAS mutation did not show any response. Metformin and trametinib combination showed synergistic inhibition of RAS mutated VOA1312 and VOA1056 cells, but not for non-Ras mutated VOA5646 cells. Metformin and trametinib increased phosphorylated AMPK expression in LGSOC lines with combination showing stronger expression. Trametinib decreased 42/44 mitogen activated kinase phosphorylation in all cell lines, while metformin and combination had no significant effect. 2-DG significantly inhibited glycolysis in all LGSOC lines and combination with metformin showed synergistic inhibitory effect.. Metformin alone or in combination with MEK and glycolytic inhibitors may be a potential therapy for LGSOC, a cancer that is indolent but chemo-resistant.

Topics: AMP-Activated Protein Kinases; Antimetabolites; Blotting, Western; Carcinoma, Ovarian Epithelial; Cell Line, Tumor; Cell Proliferation; Deoxyglucose; Drug Synergism; Drug Therapy, Combination; Female; Humans; Hypoglycemic Agents; Metformin; Neoplasm Grading; Neoplasms, Cystic, Mucinous, and Serous; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; ras Proteins; Signal Transduction