Dysregulation of hsa-miR-34a and hsa-miR-449a leads to overexpression of PACS-1 and loss of DNA damage response (DDR) in cervical cancer

Abstract

We have observed over expression of PACS-1, a cytosolic sorting protein in primary cervical tumors. Absence of exonic mutations and overexpression at the RNA level suggested a transcriptional and/or post transcriptional regulation. UCSC genome browser analysis of PACS-1 mRNA revealed two 8 base target sequences at the 3’ terminus for hsa-miR-34a and hsa-miR-449a. Quantitative RT-PCR and northern blot studies showed reduced or loss of expression of the two miRNAs in cervical cancer cell lines and primary tumors indicating dysregulation of these two miRNAs in cervical cancer. Loss of PACS-1 with siRNA or exogenous expression of hsa-miR-34a or hsa-miR-449a in HeLa and SiHa cervical cancer cell lines resulted in DNA damage response (DDR), S-phase cell cycle arrest and reduction in cell growth. Furthermore, the siRNA studies showed that loss of PACS-1 expression was accompanied by increased nuclear γH2AX expression, K-382-p53 acetylation and genomic instability. PACS-1 re-expression through LNA-hsa-anti-miR-34a or 449a or PACS-1 cDNA transfection led to the reversal of DDR and restoration of cell growth. Release of cells post 24_h serum starvation showed PACS-1 nuclear localization at G1-S phase of the cell cycle. Our results therefore indicate that the loss of hsa-miR-34a and hsa-miR-449a expression in cervical cancer leads to overexpression of PACS-1 and suppression of DNA damage response resulting in the development of chemo-resistant tumors.

Proteins from the DNA Damage Response: Regulation, Dysfunction, and Anticancer Strategies

“…Tumor cell proliferation is also linked to the remodeling of the immune microenvironment through the deregulation of rhythmic expression of cyclin genes and the P21 WAF/CIP1 cell cycle inhibitor when the circadian rhythm is disrupted [209]. A virus such as the human papillomavirus reinitiates DNA replication by abrogating the cell cycle checkpoint proteins P53 and Rb (retinoblastoma protein), leading to an unscheduled S phase entry, followed by replication stress, DDR, and carcinogenesis [210]. In NHEJ, the ATP dependent helicases Ku70 and Ku80 form a heterocomplex with DNA-ends, and Ku80 C terminus recruits DNA-PK, a phosphatidylinositol 3-kinase related serine/threonine kinase [211].…”

Recent Findings on Thymoquinone and Its Applications as a Nanocarrier for the Treatment of Cancer and Rheumatoid Arthritis

“…TQ also halts the PI3K/AKT signaling pathway by upregulating PTEN, thus interfering with GSK-3β activity, enhancing β-catenin degradation, and decreasing MMP-9 and MMP-2 levels in esophageal cancer cells (Eca109 cells) [ 83 ]. MicroRNA-34a (miR-34a) expression is vital to cancer development and metastasis [ 90 ], and its expression is reduced by TQ in human metastatic breast cancers (MBC) compared to normal breast tissues [ 91 ]. Altogether, microRNA-34a can act as therapy either alone or in combination with TQ, and synergize therapeutic potential [ 92 ].…”

Dynamical modeling of miR-34a, miR-449a, and miR-16 reveals numerous DDR signaling pathways regulating senescence, autophagy, and apoptosis in HeLa cells

“…Recent research suggests that manipulating miRNA expression may reflect DNA damage challenges (e.g., radiation, chemotherapy, and reactive oxygen species (ROS)). Veena et al 2 have discovered that Phosphofurin acidic cluster sorting protein 1 (PACS1) expression is increased in HeLa cells 2 (see Fig. 1 ).…”

“…In this context, the study of Veena et al 2 and Huang et al 7 provided evidence that transcription of these miRNAs (miR-16, miR-34a, and miR-449a) are associated with the induction of autophagy, apoptosis, and senescence at the functional and stable G1/S checkpoint in HeLa cells. However, the precise molecular mechanisms of these miRNAs (miR-16, miR-34a, and miR-449a) synergistically or individually in cervical cancer are still unclear.…”