No abstract

NSC243928 induces cell death in triple-negative breast cancer cells in a LY6K-dependent manner. NSC243928 has been reported as an anti-cancer agent in the NCI small molecule library. The molecular mechanism of NSC243928 as an anti-cancer agent in the treatment of tumor growth in the syngeneic mouse model has not been established. With the success of immunotherapies, novel anti-cancer drugs that may elicit an anti-tumor immune response are of high interest in the development of novel drugs to treat solid cancer. Thus, we focused on studying whether NSC243928 may elicit an anti-tumor immune response in the in vivo mammary tumor models of 4T1 and E0771. We observed that NSC243928 induced immunogenic cell death in 4T1 and E0771 cells. Furthermore, NSC243928 mounted an anti-tumor immune response by increasing immune cells such as patrolling monocytes, NKT cells, B1 cells, and decreasing PMN MDSCs in vivo. Further studies are required to understand the exact mechanism of NSC243928 action in inducing an anti-tumor immune response in vivo, which can be used to determine a molecular signature associated with NSC243928 efficacy. NSC243928 may be a good target for future immuno-oncology drug development for breast cancer.

No abstract

TGF-β signaling promotes migration, invasion, and distant colonization of cancer cells in advanced metastatic cancers. TGF-β signaling suppresses the anti-tumor immune response in a tumor microenvironment, allowing sustained tumor growth. TGF-β plays an important role in normal physiology; thus it is no surprise that the clinical development of effective and safe TGF-β inhibitors has been hampered due to their high toxicity. We discovered that increased expression of LY6K in cancer cells led to increased TGF-β signaling and that inhibition of LY6K could lead to reduced TGF-β signaling and reduced in vivo tumor growth. LY6K is a highly cancer-specific protein, and it is not expressed in normal organs except in the testes. Thus, LY6K is a valid target for developing therapeutic strategies to inhibit TGF-β signaling in cancer cells. We employed in vitro pull-down assays and molecular dynamics simulations to understand the structural determinants of the TGF-β receptor complex with LY6K. This combined approach allowed us to identify the critical residues and dynamics of the LY6K interaction with the TGF-β receptor complex. These data are critical in designing novel drugs for the inhibition of TGF-β in LY6K expressing cancer, induction of anti-tumor immune response, and inhibition of tumor growth and metastatic spread.