Project description:CDK4/6i alone have proven to be largely ineffective in breast cancer, even in the presence of functional retinoblastoma protein (pRB). In this study, we investigated the role of the RANK pathway in the response to CDK4/6i in pRB-proficient TNBC. Transcriptomic analysis of allografts revealed that combining CDK4/6i with RANKLi more effectively mounts an anti-tumoral immune response.
Project description:CDK4/6i alone have proven to be largely ineffective in TNBC, even in the presence of functional retinoblastoma protein (pRB). In this study, we investigated the role of the RANK pathway in the response to CDK4/6i in pRB-proficient TNBC. Transcriptomic analysis of xenografts revealed that combining CDK4/6i with RANKLi more effectively arrested the cell cycle.
Project description:MMTV-PyMT late carcinomas, orthotopically injected in syngeneic RANK+/+ mice were digested until single cells and cultured over Matrigel in the prescence or abscence of RANKL for 24 hours.
Project description:LKB1 deficiency in lung adenocarcinoma (LUAD) leads to primary resistance to immune checkpoint inhibitors. However, the underlying molecular mechanism remains unclear. Here, we showed that LKB1 deficiency significantly affected the tumor immune landscape by decreasing the infiltration of most immunocyte populations and downregulating the expression of intercellular adhesion molecule-1 (ICAM1). LKB1 deficiency promoted cancer evasion due to loss of ICAM1-mediated antitumor immunity, including immune-competent cell cytotoxicity and tumor infiltration. CDK4/6 inhibitors reversed this process in a targeted manner. A tailored combination strategy using CDK4/6 inhibitors and anti-PD-1 antibodies slowed tumor growth and increased survival in syngeneic mouse models of LKB1-deficient lung adenocarcinoma. Combining a CDK4/6 inhibitor, which is clinically approved, with PD-1 blockade therapy is thus a promising option for lung adenocarcinoma patients harboring LKB1 mutations.
Project description:Triple-negative breast cancer (TNBC) is aggressive and difficult, and few targeted therapies are available to treat this patient population. The androgen receptor (AR) has emerged as a potential target in breast cancer. Newer generation AR inhibitors, such as Seviteronel (Sevi), are unique in their ability to inhibit AR both directly and by blocking upstream androgen synthesis. The purpose of this study was to investigate the pre-clinical activity of Sevi in TNBC and further explore the effectiveness of targeting both androgen biosynthesis and AR activity in combination with other downstream acting agents. AR overexpressing (AR+) TNBC cell lines, xenografts and androgen responsive patient-derived xenograft (PDX) models were using to show how effectively Sevi inhibits AR activity and cell/tumor proliferation. Single cell RNA-sequencing of the AR+ cell line MDA-MB-453 illustrated heterogeneity in AR levels and identified cell cycle pathway activation in ARHigh versus ARLow expressing cells. Combination treatment with the cell cycle CDK4/6 inhibitor abemaciclib and Sevi showed synergy in AR+ TNBC cells and increased effectiveness, compared to each drug alone, in an AR+ TNBC xenograft model. While cell cycle inhibitors have been approved for use in hormone-receptor positive breast cancer, our studies suggest that these drugs may be equally effective in AR+ TNBC cells, especially when combined with AR antagonists. Implications. These data suggest that targeting AR signaling at multiple points throughout the pathway may be an effective was to treat patients with AR+ TNBC.
Project description:The cell line-derived xenografts and patient derived xenografts have limited use in cancer immunotherapy evaluation because an immune compromised host is required for xenotransplantation. Syngeneic mouse models are derived by transplanting established mouse cell lines or tumor tissues to strain matched mouse hosts, which are better suited to study the interplay between immune and tumor cells. We investigated the differences as well as similarities of a panel of ten mouse syngeneic models to features of human tumors by proteomics, which will provide valuable information to assist experimental biologists in model selection.
Project description:Mixed Lineage Kinase 3 (MLK3) is a viable emerging target for neoplastic diseases; however, it is uncertain whether its activators or inhibitors can act as anti-neoplastic agents. Previously, we reported that the kinase activity of MLK3 was significantly higher in triple-negative breast cancer (TNBC) than hormone receptor-positive human breast tumors where estrogen inhibits MLK3 kinase activity and provides a survival advantage to ER+ breast cancer cells. Here, we identified that in TNBC, the higher MLK3 kinase activity paradoxically promotes cell survival via activating the downstream PAK1-NF-kB axis. The MLKs/MLK3 inhibitors, CEP-1347, and URMC-099 induced cell death in TNBC but not in hormone receptor-positive breast cancer cells. The MLKs/MLK3 inhibitors reduced TNBC cell line and patient-derived xenografts’ tumor burden. The MLKs/MLK3 inhibitors also decreased MLK3, PAK1, and NF-kB protein expression and activation, prompting cell death in breast PDXs. The RNA-seq analyses indicated several genes downregulated upon MLKs/MLK3 inhibition in tumors. Significantly NGF/TrkA MAPK pathway was enriched in tumors undergoing tumor reduction by CEP-1347 and URMC-099. The tumors or cell lines that did respond to MLKs/MLK3 inhibitors had higher TrkA expression, and TrkA overexpression in the presence of MLK3 sensitized the TNBC cell line that initially did not respond to MLKs/MLK3 inhibitors. These results suggest that the functions of MLK3 in cancer cells are dependent on downstream targets/signaling, and rationalized decision needs to be made before using its inhibitor in different breast cancer subtypes. Our data also highlight that MLK3 inhibitor warrants further investigation for treating TNBC.
Project description:The expression levels of JMJD6 and its correlation with H2A.XY39ph differed in TNBC and non-TNBC cells. In addition, we have previously shown that H2A.XY39ph levels are positively correlated with tumor size, histological grade and advanced TNM stage in breast cancer. To analyze the role of JMJD6 in regulating the characteristics of different subtypes of breast cancer, the transcriptomes of TNBC cells (SUM159) and non-TNBC cells (HCC1569) that overexpressed JMJD6 were compared. We speculate that JMJD6 overexpression cause autophagy pathway activation in TNBC via enhancing ATG genes expression.
Project description:Triple-Negative Breast Cancer (TNBC) has a poor prognosis and adverse clinical outcomes among all breast cancer subtypes as there is no available targeted therapy. Overexpression of Enhancer of zeste homolog 2 (EZH2) has been shown to correlate with TNBC's poor prognosis, but the contribution of EZH2 catalytic (H3K27me3) versus non-catalytic EZH2 (NC-EZH2) function in TNBC progression remains elusive. We reveal that selective hyper-activation of functional EZH2 (H3K27me3) over NC-EZH2 alters TNBC metastatic landscape and fosters its peritoneal metastasis, particularly splenic. Instead of H3K27me3-mediated repression of gene expression; here, it promotes KRT14 transcription by attenuating binding of repressor Sp1 to its promoter. Further, KRT14 loss significantly reduces TNBC migration, invasion, and peritoneal metastasis. Consistently, human TNBC metastasis displays positive correlation between H3K27me3 and KRT14 levels. Finally, EZH2 knockdown or H3K27me3 inhibition by EPZ6438 reduces TNBC peritoneal metastasis. Altogether, our preclinical findings suggest a rationale for targeting TNBC with EZH2 inhibitors.