Proteomic Identification of DNA-PK Involvement within the RET Signaling Pathway
نویسندگان
چکیده
Constitutive activation of the Rearranged during Transfection (RET) proto-oncogene leads to the development of MEN2A medullary thyroid cancer (MTC). The relatively clear genotype/phenotype relationship seen with RET mutations and the development of MEN2A is unusual in the fact that a single gene activity can drive the progression towards metastatic disease. Despite knowing the oncogene responsible for MEN2A, MTC, like most tumors of neural crest origin, remains largely resistant to chemotherapy. Constitutive activation of RET in a SK-N-MC cell line model reduces cell sensitivity to chemotherapy. In an attempt to identify components of the machinery responsible for the observed RET induced chemoresistance, we performed a proteomic screen of histones and associated proteins in cells with a constitutively active RET signaling pathway. The proteomic approach identified DNA-PKcs, a DNA damage response protein, as a target of the RET signaling pathway. Active DNA-PKcs, which is phosphorylated at site serine 2056 and localized to chromatin, was elevated within our model. Treatment with the RET inhibitor RPI-1 significantly reduced s2056 phosphorylation in RET cells as well as in a human medullary thyroid cancer cell line. Additionally, inhibition of DNA-PKcs activity diminished the chemoresistance observed in both cell lines. Importantly, we show that activated DNA-PKcs is elevated in medullary thyroid tumor samples and that expression correlates with expression of RET in thyroid tumors. These results highlight one mechanism by which RET signaling likely primes cells for rapid response to DNA damage and suggests DNA-PKcs as an additional target in MTC.
منابع مشابه
A Review of Driver Genetic Alterations in Thyroid Cancers
Thyroid cancer is a frequent endocrine related malignancy with continuous increasing incidence. There has been moving development in understanding its molecular pathogenesis recently mainly through the explanation of the original role of several key signaling pathways and related molecular distributors. Central to these mechanisms are the genetic and epigenetic alterations in these pathways, su...
متن کاملThe Role of Wnt Signaling Pathway on the Expression of TGFβ 1 and TGFβ 2 in Cultured Rat Cortical Astrocytes
Introduction: Astrocytes, the most abundant glia in the central nervous system, modulate neuronal survival and function. Astrocytic functions are mediated by synthesis and secretion of wide ranges of polypeptides through mechanism (s) poorly understood. Among these, TGFβs are synthesized and released by the astrocytes. In this study, the involvement of Wnt signaling pathway on the synthesi...
متن کاملDysregulation of the WNT Signaling Pathway Through Methylation of Wnt Inhibitory Factor 1 and Dickkopf-1 Genes among AML Patients at the Time of Diagnosis
Background: In acute myeloblastic leukemia, a large number of tumor suppressor genes are silenced through DNA methylation such as CDKN2B & p73. Wnt inhibitory factor 1 (WIF1) and Dickkopf-3 (DKK-1) are negative regulators of Wnt signaling pathway. In the present study, we evaluated the methylation status of WIF1 and DKK-1 genes in acute myeloblastic leukemia patients. Patients and Methods: ...
متن کاملThe protective effect of nano-curcumin in experimental model of acute pancreatitis: The involvement of TLR4/NF-kB pathway
Objective(s): The objective of the present study is to explore whether Nanocurcumin improves pancreatic inflammation through the inhibition of the TLR4/NFkB signaling pathway in cerulein-induced acute pancreatitis. Methods: Acute pancreatitis was induced by five intraperitoneal (i.p.) injection of cerulein (50 μg/kg) with 1h intervals. Vehicle and nanocurcumin (100mg/kg/day) were given to the a...
متن کاملDNA-PK Target Identification Reveals Novel Links between DNA Repair Signaling and Cytoskeletal Regulation
The DNA-dependent protein kinase (DNA-PK) may function as a key signaling kinase in various cellular pathways other than DNA repair. Using a two-dimensional gel electrophoresis approach and stable DNA double-strand break-mimicking molecules (Dbait32Hc) to activate DNA-PK in the nucleus and cytoplasm, we identified 26 proteins that were highly phosphorylated following DNA-PK activation. Most of ...
متن کامل