Project description:We have previously established an in vitro model of PARPi-resistant ovarian cancer by long-term exposure of UWB1.289 ovarian cancer cells (and their isogenic derivatives UWB1.289+BRCA1) to incrementally ascending olaparib concentrations. After finalizing this model, we performed RNA-seq, in order to identify differentially expressed transcript in the PARPi-resistant cells, with a focus on genes related to DNA-repair, multi-drug resistance and EMT. As a result, we show that the phenotype of PARPi resistance is associated with EMT-like traits and up-regulation of selective multi-drug related transcripts.
Project description:Poly (ADP-ribose) Polymerase (PARP) inhibitors (PARPi) are approved to treat recurrent ovarian cancer with BRCA1 or BRCA2 mutations, and as maintenance therapy for recurrent platinum sensitive ovarian cancer (BRCA wild-type or mutated) after treatment with platinum. However, the acquired resistance against PARPi remains a clinical hurdle. Our previous study has demonstrated that PARPi can enhance the Aldehyde dehydrogenase (ALDH) activity in ovarian cancer cells, mainly through inducing expression of ALDH1A1, an isoform of the ALDH family. In addition, an ALDH1A1 selective inhibitor can synergize with olaparib in killing EOC cells carrying BRCA2 mutation in both in vitro cell culture and the in vivo xenograft animal model. In order to elucidating the mechanism by which ALDH1A1 renders PARPi resistance to ovarian cancer, we performed RNA-seq analysis to identify genes whose expression can be regulated by ALDH1A1.
Project description:Aberrant androgen receptor (AR)-mediated transcription is a critical driver in progression of human prostate cancer. It's known that different doses of androgens can elicit differential transcriptional and proliferative responses in prostate-tumor cells. Here, we set out to examine the androgenic regulation of glycoprotein expression in the membrane fraction of prostate-tumor cells that could serve as mediators or markers of androgen-induced proliferative responses observed in prostate-tumor cells. A bioanalytical workflow involving lectin-affinity chromatography and label-free quantitative mass spectrometry was used to identify androgen-sensitive glycomembrane protein expression associated with androgen-mediated proliferation. This study would facilitate the identification of surface membrane proteins involved in androgen-mediated proliferation and provide potential therapeutic targets in the detection treatment of proliferation prostate-tumors.
Project description:Although Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have been approved in multiple diseases, including BRCA1/2 mutant breast cancer, responses are usually transient thus requiring the development of combination therapies that can capitalize on PARPi activity. We thus explored mechanisms underlying sensitivity and resistance to PARPi using two intrinsically sensitive and resistant syngeneic murine breast cancer models. Our data indicate that the PARPi sensitive tumor model has a high ratio of M1 anti-tumor/M2 pro-tumor macrophages with the M1/M2 ratio being increased by PARPi. In contrast the PARPi resistant tumor model had very low levels of M1 macrophages and thus a low M1/M2 ratio that was not altered by PARPi. Our data indicate that co-transplantation of the PARPi sensitive and the PARPi resistant tumor results in accumulation of M2 macrophages in the sensitive tumor, rendering the sensitive tumor PARPi resistant. C5aR1 and RPS19/C5aR1 signaling is selectively elevated in the M2 macrophages that are associated with PARPi resistance. Strikingly C5aR1 targeting decreased M2 macrophages, while sparing M1 macrophages rendering PARPi resistant tumors sensitive to PARPi. Consistent with the murine data, human breast cancers with high C5aR1 levels have a poor response to immune checkpoint blockade. Thus targeting C5aR1 may represent a therapeutic approach to selectively deplete M2 macropahges and engender sensitivity to PARPi and potentially other therapeutic approaches.