Biology subjects

Fallatah, A.

Publications and source records attributed to Fallatah, A..

3 recordsLinked to original sources

bioRxiv2026

Stage-Specific Regulation of DNA Damage Repair by the Circadian Regulator, CRY1, in Prostate Cancer

Circadian dysregulation is increasingly linked to prostate cancer (PCa) progression, yet its role in directing DNA damage response (DDR) pathway selection remains poorly understood. Here, we identify circadian cryptochrome 1 (CRY1), a core circadian regulator, as a stage-specific determinant of DDR dependencies. Integrated transcriptomic and CRISPR-based analyses reveal that CRY1 promotes non-homologous end joining (NHEJ) and base excision repair (BER)-associated programs in hormone-sensitive disease (HTS), while driving a switch toward homologous recombination (HR) dependency in castration-resistant prostate cancer (CRPC). Mechanistically, CRY1 couples proliferative signaling to genome maintenance, enabling tumor cells to tolerate genotoxic stress and sustain progression. Notably, loss of CRY1 exposes distinct, context-dependent DDR vulnerabilities, revealing repair plasticity as a targetable actionable feature of disease evolution. These findings position CRY1 as a central regulator of DDR rewiring and support CRY1-directed combination strategies with DDR inhibitors as a rationale to delay or prevent progression to advanced, treatment-resistant PCa.

cancer biology↗

bioRxiv2022

HNRNPK is retained in the cytoplasm by Keratin 19 to stabilize target mRNAs

Heterogeneous nuclear ribonucleoprotein K (HNRNPK) regulates pre-mRNA processing and long non-coding RNA localization in the nucleus. It was previously shown that shuttling of HNRNPK to the cytoplasm promotes cell proliferation and cancer metastasis. However, the mechanism of HNRNPK cytoplasmic localization, its cytoplasmic RNA ligands, and impact on posttranscriptional gene regulation remain uncharacterized. Here we show that the intermediate filament protein Keratin 19 (K19) directly interacts with HNRNPK and sequesters it in the cytoplasm. Correspondingly, in K19 knockout breast cancer cells, HNRNPK does not localize in the cytoplasm, resulting in reduced cell proliferation. We mapped cytoplasmic HNRNPK target mRNAs using PAR-CLIP where transcriptome data to show that, in the cytoplasm, HNRNPK stabilizes target mRNAs bound to the 3 untranslated region at the expected C-rich sequence elements. Furthermore, these mRNAs are typically involved in cancer progression and include the p53 signaling pathway that is dysregulated upon HNRNPK knockdown or K19 knockout. This study identifies how a cytoskeletal protein can directly regulate gene expression by controlling subcellular localization of RNA binding proteins to support pathways involved in cancer progression.

molecular biology↗

bioRxiv2020

Keratin 19 maintains E-cadherin localization at the cell surface and stabilizes cell-cell adhesion of MCF7 cells

A cytoskeletal protein keratin 19 (K19) is highly expressed in breast cancer but its effects on breast cancer cell mechanics are unclear. Using KRT19 knockout (KO) cells and cells where K19 expression was rescued, we found that K19 is required to maintain rounded epithelial-like shape and tight cell-cell adhesion of MCF7 cells. A loss of K19 resulted in a lower level of plakoglobin and internalization of E-cadherin in early and recycling endosomes. Inhibiting internalization restored cell-cell adhesion of KRT19 KO cells, suggesting E-cadherin internalization contributes to defective adhesion. Ultimately, while K19 inhibited cell migration, it was required for cells to form colonies in suspension. Our results suggest that K19 stabilizes E-cadherin complexes at the cell membrane to maintain cell-cell adhesion which inhibits cell migration but provides growth and survival advantages for circulating tumor cells. These findings provide context-dependent roles of K19 during metastasis.

cell biology↗