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Chakrabarti, O.

Publications and source records attributed to Chakrabarti, O..

2 recordsLinked to original sources

Androgen receptor plays critical role in regulating cervical cancer cell migration

Cervical cancer (CC) is the second most common cancer among women in India and the fourth worldwide. While major genes and pathways have been studied, further research is needed to identify candidates for targeted therapy in metastatic disease. This study used a network biology approach to identify key genes in disease progression. Stage-specific cervical cancer protein-protein interaction networks (PPIN) were constructed by overlaying stage-specific, patient-derived transcriptomics data onto a human protein-protein interaction network (HPPIN). Graph-theory-based network analysis identified important interacting proteins (IIPs) with maximum connectivity, high centrality scores, and significant global and local network perturbation scores. Among the identified IIPs, the Androgen receptor (AR) emerged as one of the crucial yet understudied regulator in cervical cancer. Patient samples and in vitro experiments showed significant downregulation in cervical cancer. Ligand-dependent overexpression of AR reduced cancer cell migration while failed to induce apoptosis in CC cell lines. Downregulation of mesenchymal markers and restoration of epithelial markers suggested ARs potential in reversing invasive properties of cervical cancer cells. AR overexpression upregulated its downstream target PTEN and restored GSK3{beta} activity by interfering with AKT phosphorylation, probably leading to degradation of mesenchymal markers. Further studies showed AR reduced cell motility by hindering focal adhesion formation and Actin filament assembly. An increased G-Actin ratio suggested AR disrupted cytoskeletal dynamics through the RhoA/ROCK1/LIMK1/CFL1 pathway, impeding cervical cancer cell spread.

cancer biology↗

The impact of ERUPR on mitochondrial integrity mediated by PDK4

ER and mitochondrial stress are often interconnected and considered as major contributors to aging as well as neurodegeneration. Co-ordinated induction of ERUPR and mitoUPR has been observed in diabetes and pulmonary disorders. However, in the context of aging and neurodegeneration, regulation of this intra-organellar crosstalk has remained relatively elusive. Here, we demonstrate that pyruvate dehydrogenase kinase 4 (PDK4), a mitochondrial protein accumulates at the ER-mitochondrial contact sites (MAMs) during ER stress. Classically, PDK4 is known to phosphorylate PDHA1 (pyruvate dehydrogenase E1 subunit alpha 1), and plays a significant role in regulating the oxidative phosphorylation driven ATP production. In this study, we propose a non-canonical function of PDK4; we show that it acts as a connecting link between ERUPR and mitoUPR with significance in aging and neurodegeneration. Transcriptomics analyses show increased PDK4 levels upon drug induced ER stress. We detect elevated PDK4 levels in brain lysates of Alzheimers disease (AD) patients, as well as in in vivo and ex vivo AD models. Additionally, exogenous expression of PDK4 was found to refine ER-mitochondrial communication, significantly altering mitochondrial morphology and function. Further, we also observe defective autophagic clearance of mitochondria under such conditions. It is prudent to suggest that elevated PDK4 levels could be one of the key factors connecting ERUPR with mitoUPR, a phenotypic contributor in aging and at least some neurodegenerative diseases.

molecular biology↗