pyrimidinones and Nasopharyngeal-Carcinoma

The development of chemoresistance is the major cause of treatment failure in nasopharyngeal carcinoma (NPC). Although 'paradoxical' activation of extracellular signal-regulated kinase (ERK) has been shown to contribute resistance to anticancer treatment, the role of ERK in NPC chemoresistance has not been yet revealed. In this work, we report that trametinib, a clinically available mitogen-activated protein kinase inhibitor for melanoma treatment, overcomes NPC chemoresistance via suppressing ERK activation induced by chemotherapy. We first showed that trametinib at nanomolar concentrations was active against NPC cells and acted synergistically with cisplatin. Trametinib remarkably decreased phosphorylation of ERK and its downstream effector in NPC cells. We next showed that cisplatin treatment stimulates ERK signaling, and furthermore that this can be abolished by trametinib. We finally generated cisplatin-resistant NPC models and demonstrated that trametinib was effective in inhibiting cisplatin-resistant NPC growth, colony formation and survival via suppressing ERK signaling in vitro and in vivo. Our work demonstrates the potential of trametinib in overcoming chemoresistance in preclinical NPC models and provides evidence of initializing clinical trials of using trametinib for NPC treatment.

Topics: Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cisplatin; Drug Resistance, Neoplasm; Drug Synergism; Extracellular Signal-Regulated MAP Kinases; Humans; MAP Kinase Signaling System; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Pyridones; Pyrimidinones; Signal Transduction

The Wnt signaling pathway is known to serve an important role in the control of cell migration. The present study analyzed the mechanisms underlying the in vitro modulation of the migration of nasopharyngeal carcinoma (NPC) cells by the CREB‑binding protein/catenin antagonist and Wnt modulator ICG‑001. The results revealed that ICG‑001‑mediated inhibition of tumor cell migration involved downregulated mRNA and protein expression of the Wnt target gene cluster of differentiation (CD)44. It was also demonstrated that ICG‑001 downregulated the expression of CD44, and this effect was accompanied by restored expression of microRNA (miRNA)‑150 in various NPC cell lines. Using a CD44 3'‑untranslated region luciferase reporter assay, miR‑150 was confirmed to be a novel CD44‑targeting miRNA, which could directly target CD44 and subsequently regulate the migration of NPC cells. The present study provides further insight into the inhibition of tumor cell migration through the modulation of miRNA expression by the Wnt modulator ICG‑001.

Topics: Animals; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cell Movement; Female; Gene Expression Regulation, Neoplastic; Humans; Hyaluronan Receptors; Mice; MicroRNAs; Nasopharyngeal Carcinoma; Pyrimidinones; RNA, Messenger; RNA, Small Interfering; Wnt Signaling Pathway

Nasopharyngeal carcinoma (NPC) is an EBV-associated epithelial malignancy prevalent in southern China. Presence of treatment-resistant cancer stem cells (CSC) may associate with tumor relapse and metastasis in NPC. ICG-001 is a specific CBP/β-catenin antagonist that can block CBP/β-catenin-mediated transcription of stem cell associated genes and enhance p300/β-catenin-mediated transcription, thereby reducing the CSC-like population via forced differentiation. In this study, we aimed to evaluate the effect of ICG-001 on the CSC-like population, and the combination effect of ICG-001 with cisplatin in the C666-1 EBV-positive NPC cells. Results showed that ICG-001 inhibited C666-1 cell growth and reduced expression of CSC-associated proteins with altered expression of epithelial-mesenchymal transition (EMT) markers. ICG-001 also inhibited C666-1 tumor sphere formation, accompanied with reduced SOX2(hi)/CD44(hi) CSC-like population. ICG-001 was also found to restore the expression of a tumor suppressive microRNA-145 (miR-145). Ectopic expression of miR-145 effectively repressed SOX2 protein expression and inhibited tumor sphere formation. Combination of ICG-001 with cisplatin synergistically suppressed in vitro growth of C666-1 cells and significantly suppressed growth of NPC xenografts. These results suggested that therapeutically targeting of the CBP/β-catenin signaling pathway with ICG-001 can effectively reduce the CSC-like population and combination with cisplatin can effectively suppress the growth of NPC.

Topics: Animals; Antineoplastic Agents; beta Catenin; Bridged Bicyclo Compounds, Heterocyclic; Carcinoma; Cell Line, Tumor; Cell Proliferation; Cisplatin; Drug Synergism; Epithelial-Mesenchymal Transition; Herpesvirus 4, Human; Humans; Hyaluronan Receptors; Mice; Mice, Nude; MicroRNAs; Microscopy, Confocal; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplastic Stem Cells; p300-CBP Transcription Factors; Pyrimidinones; RNA Interference; RNA, Small Interfering; Signal Transduction; SOXB1 Transcription Factors; Transplantation, Heterologous

Nasopharyngeal carcinoma (NPC) is a rare but highly invasive cancer. As radiotherapy is the primary treatment for NPC, this offers a rationale to investigate if uncoupling the DNA damage responses can sensitize this cancer type. The G2 DNA damage checkpoint is controlled by a cascade of protein kinases: ATM/ATR, which phosphorylates CHK1/CHK2, which in turn phosphorylates WEE1. A number of small molecule inhibitors have been developed against these kinases as potential therapeutic agents. Here we demonstrated that compare to that in immortalized nasopharyngeal epithelial cells, ATR, CHK1, and WEE1 were overexpressed in NPC cell lines. Inhibitors of these kinases were unable to promote extensive mitotic catastrophe in ionizing radiation-treated NPC cells, indicating that they are not very effective radiosensitizer for this cancer. In the absence of prior irradiation, however, mitotic catastrophe could be induced with inhibitors against CHK1 (AZD7762) or WEE1 (MK-1775). NPC cells were more sensitive to WEE1 inactivation than nasopharyngeal epithelial cells. Targeting CHK1 and WEE1 together induced more extensive mitotic catastrophe than the individual components alone. Taken together, our results show that NPC cells depend on CHK1 and WEE1 activity for growth and that inhibitors of these kinases may serve as potential therapeutics for NPC.

Topics: Animals; Ataxia Telangiectasia Mutated Proteins; Carcinoma; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Checkpoint Kinase 1; DNA Damage; Flow Cytometry; G2 Phase; Gene Expression Regulation, Neoplastic; Green Fluorescent Proteins; HeLa Cells; Humans; Mice; Mice, Inbred BALB C; Mitosis; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Invasiveness; Neoplasm Transplantation; Nuclear Proteins; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Pyrimidinones; RNA Interference; Thiophenes; Urea