Biology subjects

Rose, P. G.

Publications and source records attributed to Rose, P. G..

3 recordsLinked to original sources

bioRxiv2021

Lymphocyte-specific Protein Tyrosine Kinase Regulates Homologous Recombination (HR) DNA Repair and Targeting Enhances PARPi Utility in HR Proficient Ovarian Cancer

Poly-ADP Ribose Polymerase (PARP) targeted therapy is clinically approved for the treatment of homologous recombination (HR) repair deficient tumors. The remarkable success in treatment of HR repair deficient cancers has not translated to HR-proficient cancer. Our studies identify the mechanism of non-receptor lymphocyte-specific protein tyrosine kinase (LCK) in HR repair in endometrioid epithelial ovarian cancer (eEOC). LCK expression is induced and activation in the nucleus in response to DNA damage insult. LCK inhibition attenuates expression of RAD51, BRCA1, and BRCA2 proteins necessary for HR-mediated DNA repair, sufficient to suppress RAD51 foci formation, and augments {gamma}H2AX foci formation. Mechanistically, DNA damage leads to direct interaction of LCK with RAD51 and BRCA1 in a kinase dependent manner. Attenuation of LCK sensitized HR-proficient eEOC cells to PARP inhibitor in cell culture and pre-clinical mouse studies. These findings identify a new mechanism for expanding utility of PARP inhibitors in HR proficient ovarian cancer. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/433791v2_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@1715c60org.highwire.dtl.DTLVardef@167cb5forg.highwire.dtl.DTLVardef@158d807org.highwire.dtl.DTLVardef@1ced201_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2020

Pretreatment with LCK Inhibitors Chemosensitizes Cisplatin-Resistant Endometrioid Ovarian Tumors

ObjectiveTo evaluate LCK inhibitors (LCKi) as chemosensitizing agents for platinum-resistant endometrioid ovarian carcinoma. MethodsKM Plotter survival data was obtained for endometrioid ovarian cancer based on LCK mRNA expression. Cisplatin resistant endometrioid ovarian carcinoma cell lines were cultured and treated first with LCKi or vehicle, then combination LCKi-cisplatin. Cell viability was assessed via CellTiter-Glo, and apoptosis with Caspase 3/7 Assay. Protein lysates were isolated from treated cells, with{gamma} -H2Ax, a DNA adduct marker, assessed. In vivo study compared mice treated with vehicle or LCK inhibitor followed by LCK inhibitor, cisplatin, or combination therapy. One-way ANOVA and two sample t-test were used to assess statistical significance with GraphPad Prism. ResultsKM plotter data indicated LCK expression is associated with significantly worse median progression-free survival (HR 3.19, p=0.02), and a trend toward decreased overall survival in endometrioid ovarian tumors with elevated LCK expression (HR 2.45, p=0.41). In vitro, cisplatin resistant ovarian endometrioid cells treated first with LCKi followed by combination LCKi-cisplatin treatment showed decreased cell viability and increased apoptosis. Immunoblot studies revealed inhibition of LCK led to increased expression of{gamma} -H2AX. In vivo results demonstrate treatment with LCKi followed by LCKi-cisplatin leads to significantly slowed tumor growth. ConclusionsWe identified a targetable pathway for chemosensitization of platinum resistant endometrioid ovarian cancer with initial treatment of LCKi followed by co-treatment with LCKi-cisplatin.

cancer biology↗

bioRxiv2017

CD55 regulates self-renewal and cisplatin resistance in endometrioid tumors

Effective targeting of cancer stem cells (CSCs) requires neutralization of self-renewal and chemoresistance, however these phenotypes are often regulated by distinct molecular mechanisms. Here we report the ability to target both of these phenotypes via CD55, an intrinsic cell surface complement inhibitor, which was identified in a comparative analysis between CSCs and non-CSCs in endometrioid cancer models. In this context, CD55 functions in a complement-independent manner and required lipid raft localization for CSC maintenance and cisplatin resistance. CD55 regulated self-renewal and core pluripotency genes via ROR2/JNK signaling and in parallel cisplatin resistance via LCK signaling, which induced DNA repair genes. Targeting LCK signaling via saracatinib, an inhibitor currently undergoing clinical evaluation, sensitized chemoresistant cells to cisplatin. Collectively, our findings identify CD55 as a unique signaling node that drives self-renewal and therapeutic resistance via a bifurcating signaling axis and provide an opportunity to target both signaling pathways in endometrioid tumors.\n\nSUMMARYCD55 is a membrane complement regulatory protein that attenuates complement-mediated cytotoxicity. Saygin et al. elucidate a new role for CD55 as a signaling hub for cancer stem cell self-renewal and cisplatin resistance pathways in endometrioid tumors and open a new line of research into chemotherapeutic-refractory cancers.\n\nAbbreviations

cancer biology↗