Project description:PD-0332991 is a selective inhibitor of the CDK4/6 kinases with the ability to block retinoblastoma (Rb) phosphorylation in the low nanomolar range. Here we investigate the role of CDK4/6 inhibition in human ovarian cancer. We examined the effects of PD-0332991 on proliferation, cell-cycle, apoptosis, and Rb phosphorylation using a panel of 40 established human ovarian cancer cell lines. Molecular markers for response prediction, including p16 and Rb, were studied using gene expression profiling, Western blot, and arrayCGH. Multiple drug effect analysis was used to study interactions with chemotherapeutic drugs. Expression of p16 and Rb was studied using immunohistochemistry in a large clinical cohort ovarian cancer patients. Concentration-dependent anti-proliferative effects of PD-0332991were seen in all ovarian cancer cell lines, but varied significantly between individual lines. Rb proficient cell lines with low p16 expression were most responsive to CDK4/6 inhibition. Copy number variations of CDKN2A, Rb, CCNE1, and CCND1 were associated with response to PD-0332991. CDK4/6 inhibition induced G0/G1 cell cycle arrest, blocked Rb phosphorylation in a concentration and time dependent manner, and enhanced the effects of chemotherapy. Rb proficiency with low p16 expression was seen in 97/262 (37%) of ovarian cancer patients and associated with adverse clinical outcome (progression free survival, adjusted relative risk 1.49, 95%CI 0.99-2.22, p =0.054). PD-0332991 shows promising biologic activity in ovarian cancer cell lines. Assessment of Rb and p16 expression may help select patients most likely to benefit from CDK4/6 inhibition in ovarian cancer. Gene expression of 40 individual ovarian cell lines relative to an ovarian cell line reference mix containing equal amounts of 41 ovarian cell lines (including OCC-1 which was later identified as originating from mouse). The expression data was correllated with cell line growth response to CDK 4/6 inhibitor PD-0332991 to identify genes associated with drug sensitivity and resistance.
Project description:PD-0332991 is a selective inhibitor of the CDK4/6 kinases with the ability to block retinoblastoma (Rb) phosphorylation in the low nanomolar range. Here we investigate the role of CDK4/6 inhibition in human ovarian cancer. We examined the effects of PD-0332991 on proliferation, cell-cycle, apoptosis, and Rb phosphorylation using a panel of 40 established human ovarian cancer cell lines. Molecular markers for response prediction, including p16 and Rb, were studied using gene expression profiling, Western blot, and arrayCGH. Multiple drug effect analysis was used to study interactions with chemotherapeutic drugs. Expression of p16 and Rb was studied using immunohistochemistry in a large clinical cohort ovarian cancer patients. Concentration-dependent anti-proliferative effects of PD-0332991were seen in all ovarian cancer cell lines, but varied significantly between individual lines. Rb proficient cell lines with low p16 expression were most responsive to CDK4/6 inhibition. Copy number variations of CDKN2A, Rb, CCNE1, and CCND1 were associated with response to PD-0332991. CDK4/6 inhibition induced G0/G1 cell cycle arrest, blocked Rb phosphorylation in a concentration and time dependent manner, and enhanced the effects of chemotherapy. Rb proficiency with low p16 expression was seen in 97/262 (37%) of ovarian cancer patients and associated with adverse clinical outcome (progression free survival, adjusted relative risk 1.49, 95%CI 0.99-2.22, p =0.054). PD-0332991 shows promising biologic activity in ovarian cancer cell lines. Assessment of Rb and p16 expression may help select patients most likely to benefit from CDK4/6 inhibition in ovarian cancer.
Project description:Cyclin dependent kinase 4 and 6 (CDK4/6) in complex with D-type cyclins promote cell cycle entry, at least in part through phosphorylation of the retinoblastoma tumor suppressor protein (Rb). The CDK4/6-cyclin D-Rb pathway is commonly deregulated in human cancer, often through CDK4/6 or D-type cyclin overexpression, or inactivation of the CDK4/6 antagonist p16/CDKN2A. Importantly, a substantial fraction of cancers depend on continuous CDK4/6-cyclin D kinase activity and are sensitive to CDK4/6-specific inhibitors. Here, we investigate critical CDK4/6-cyclin D functions that may determine the sensitivity to CDK4/6 inhibitors, making use of the essential roles of CDK4/6 (CDK-4) and cyclin D (CYD-1) in the nematode C. elegans. In an unbiased screen, we found that simultaneous loss of C. elegans Rb (lin-35) and down-regulation of the APC/C substrate specificity factor FZR1/Cdh1 completely overcomes CDK-4/CYD-1 requirement. Furthermore, CDK-4/CYD-1 phosphorylates specific residues in the LIN-35 Rb spacer domain and FZR-1 N-terminus that correspond to inactivating phosphorylations of the human homologs. Thus, CDK-4/CYD-1 appears to promote cell cycle entry by antagonizing not only transcriptional repression by LIN-35 Rb but also protein degradation by APC/CFZR-1. Simultaneous knockdown of Rb and FZR1 in human breast cancer cells synergistically overcomes arrest by the CDK4/6-specific inhibitor PD 00332991. These results reveal APC/CFZR1 as a putative CDK4/6-Cyclin D target and important contributing factor in the response to CDK4/6-inhibitor treatment.
Project description:Cancer cells exploit adaptive responses such as endoplasmic reticulum (ER) stress to support their survival. ER stress response is mediated in part by the ER-localized transmembrane sensor IRE1α endoribonuclease and its substrate XBP1 to regulate XBP1 target gene expression. However, the mechanism that controls the IRE1α/XBP1 pathway remains poorly understood. CARM1 is an oncogene that is often overexpressed in a number of cancer types including ovarian cancer. Here we report that CARM1 determines ER stress response by controlling the IRE1α/XBP1 pathway. Genome-wide profiling revealed that CARM1 regulates XBP1 target gene expression during ER stress response. CARM1 directly interacts with XBP1. Inhibition of the IRE1α/XBP1 pathway was effective in ovarian cancer in a CARM1-dependent manner both in vitro and in vivo in orthotopic and patient-derived xenograft models. In addition, IRE1α inhibitor B-I09 synergizes with immune checkpoint blockade anti-PD1 antibody in an immunocompetent CARM1-expressing ovarian cancer model.
Project description:Cancer cells exploit adaptive responses such as endoplasmic reticulum (ER) stress to support their survival. ER stress response is mediated in part by the ER-localized transmembrane sensor IRE1α endoribonuclease and its substrate XBP1 to regulate XBP1 target gene expression. However, the mechanism that controls the IRE1α/XBP1 pathway remains poorly understood. CARM1 is an oncogene that is often overexpressed in a number of cancer types including ovarian cancer. Here we report that CARM1 determines ER stress response by controlling the IRE1α/XBP1 pathway. Genome-wide profiling revealed that CARM1 regulates XBP1 target gene expression during ER stress response. CARM1 directly interacts with XBP1. Inhibition of the IRE1α/XBP1 pathway was effective in ovarian cancer in a CARM1-dependent manner both in vitro and in vivo in orthotopic and patient-derived xenograft models. In addition, IRE1α inhibitor B-I09 synergizes with immune checkpoint blockade anti-PD1 antibody in an immunocompetent CARM1-expressing ovarian cancer model.
Project description:The role of hyperthermic intraperitoneal chemotherapy (HIPEC) in epithelial ovarian cancer (EOC) is still controversial partly because of the poorly understood mechanism of action. Further an understanding of the underlying mechanisms could identify potential combination therapies. Here, we conduct a comprehensive multi-omics study (transcriptiome, proteome, and phosphoproteome) upon hyperthermia (HT) in ovarian cancer cells. Unbiased trans-omics approach deciphered a unique hyperthermia- induced molecular panorama and demonstrated rapid alterations in protein phosphorylation as the primary cell response upon HT. Based on the phospho-signature, we identified CDK kinases to be hyperactivated and responsible for the global signaling landscape upon HT. Molecular and functional experiments demonstrated the dynamic and reversible CDK activity, subsequent replication arrest, and early mitotic entry after HT. A follow-up drug screen identified WEE1 inhibition to synergistically kills cancer cells with HT. An in-house developed miniaturized devise delivered proof-of-concept that the combination of hyperthermia with WEE1i leads to dramatic anti-tumor responses in vivo. These findings provide new insights into how to improve the effectiveness of HIPEC in EOC.
Project description:The purpose of this study was to characterise the effects of trastuzumab and pertuzumab, either as single agents or as combination therapy on gene and protein expression in human ovarian cancer in vivo. Illumina BeadChips were used to profile the transcriptome after four days treatment of SKOV3 tumor xenografts. Although genes involved with HER2, MAP-kinase and p53 signaling pathways were commonly induced by all treatments, a greater number and variety of genes were differentially expressed by the complementary combination therapies compared to either drug on its own. The protein level of the CDK-inhibitors p21 and p27 were increased in response to both agents alone and further by the combination; pERK signaling was inhibited by all treatments; but only pertuzumab alone inhibited pAkt signaling. The expression of proliferation, apoptosis, cell division and cell cycle markers was distinct in a panel of primary ovarian cancer xenografts, suggesting heterogeneity of response in ovarian cancer and the need to establish biomarkers of response. This first comprehensive study of the molecular response to trastuzumab, pertuzumab and combination therapy in vivo highlights that there are both common and distinct downstream effects to different HER2 antibodies and that pathways may be invoked more strongly or in a different manner by a combination of agents. Some of the in vivo results for ovarian tumors differ from previous in vitro studies in breast cancer cells, emphasizing that the molecular response to anti-cancer agents involves variable and complex disease-specific interactions of signaling mechanisms. SCOV3 Ovarian cell line xenografts treated with Trastuzumab, pertuzumab or combination after 4 days
Project description:Omentum conditioned medium (OCM) is known to enhance ovarian cancer oncogenesis. In this study, miR-33b exerts tumor suppressive effects on ovarian cancer cells in response to omentum conditioned medium (OCM) treatment. To identify the molecular mechanism and main biological pathways involved in the tumor inhibiting activity by miR-33b in the ovarian cancer metastasis. To achieve this, miR-33b was stably overexpressed in ovarian cancer cell line ES-2, and the protein expression profile of miR-33b overexpressing ES-2 cells upon OCM treatment was determined.
Project description:CDK4/6 inhibitors (CDK4/6i) have significantly improved the prognosis for hormone-positive (HR+) breast cancer patients. However, the emergence of drug resistance severely limits their long-term efficacy, and CDK4/6i monotherapy remains largely ineffective against triple-negative breast cancer (TNBC). Here, we demonstrate that combining CDK4/6i with CDK7 inhibitors (CDK7i) offers a promising therapeutic strategy to overcome resistance in both HR+ breast cancer and TNBC. Kinetic analyses reveal that CDK7i primarily targets RNA polymerase II-mediated transcription, a key driver of CDK4/6i resistance by amplifying E2F activity following the degradation of the retinoblastoma protein. Consequently, the combination of CDK4/6i and CDK7i synergistically suppresses E2F activity and inhibits the growth of drug-resistant tumors. Furthermore, this combination stimulates immune response pathways and cytokine production in cancer cells, enhancing anti-tumor immunity. These findings provide critical insights into evolving CDK inhibition strategies and highlight the therapeutic application of CDK7i in breast cancer management.