Project description:Microtubule-targeting agents have been widely used for cancer treatment, yet their cancer specificity is a common challenge. In this study, we identified that CMPD1 as a promising cancer specific inhibitor. Both in vitro and in vivo experiments showed that CMPD1 efficiently inhibits tumor growth. Mechanistically, CMPD1 inhibits microtubule polymerization in mitosis. Collectively, CMPD1 has the high potential to serve as a cancer cell inhibitor.
Project description:The lack of a cure for metastatic prostate cancer (PCa) highlights the urgent need for more efficient drugs to fight this disease. Here, we report the molecular mechanism of action of the natural product 6-acetoxy-anopterine (6-AA) in malignant cells of the prostate. This potent cytotoxic alkaloid from the endemic Australian tree Anopterus macleayanus induced at low nanomolar doses a strong accumulation of LNCaP and PC3 PCa cells in mitosis, severe mitotic spindle defects and asymmetric cell divisions, ultimately leading to mitotic catastrophe accompanied by cell death through apoptosis. DNA microarray of 6-AA treated LNCaP cells combined with pathway analysis identified very similar transcriptional changes when compared to vinblastine, highlighting pathways involved in mitosis, microtubule spindle organisation and microtubule binding. Like vinblastine, 6-AA inhibited microtubule polymerization in a cell-free system and reduced microtubule polymer mass in vitro. Yet, microtubule alterations that are associated with resistance to microtubule-destabilizing drugs like vinca alkaloids or 2-methoxyestradiol did not confer cross-resistance to 6-AA, suggesting a different mechanism of microtubule interaction. Finally, 6-AA is the first-in-class microtubule inhibitor that features the unique anopterine scaffold. Altogether, this study provides a strong rationale to further develop this novel structure class of microtubule inhibitor for the treatment of malignant disease.
Project description:Natural killer cells (NK cells) play a critical role in the surveillance of tumor immunity. However, NK cell-based immunotherapy, including autologous and allogeneic NK cell reinfusion, has not brought significant clinical benefits to patients. To identify factors that control the intrinsic cytotoxicity of NK cells, we utilized the histone deacetylase inhibitor valproic acid (VPA) to develop a NK cell cytotoxicity suppression model. With RNA-seq and functional assays, we identified a previously uncharacterized lncRNA, NKCLR3 (NK cytotoxicity-associated long noncoding RNA 3), as a negative regulatory factor of NK cell-mediated cytotoxicity. NKCLR3 was significantly upregulated in VPA-treated NK cells and was negatively associated with the cytotoxicity of NK cells. Knockdown of NKCLR3 enhanced antitumor activity in NK-92MI cells. Using reverse transcription-associated capture sequencing (RAT-seq), we found that NKCLR3 functioned by targeting the Natural cytotoxicity triggering receptor 1 (NCR1) gene, which encodes the activating receptor NKp46 involved in the natural cytotoxicity. Mechanistic studies revealed that NKCLR3 interacted with the regulatory elements of NCR1 and blocked the formation of an intrachromosomal interaction that is required for optimal expression of NCR1. In addition, NKCLR3 inhibited the synthesis of NCR1 enhancer RNA. Through these dual mechanisms, NKCLR3 induced a suppressive epigenotype in the NCR1 promoter and suppressed the expression of the NCR1 gene. Thus, the NKCLR3-NCR1 axis identified in this study may serve as a novel target to improve therapeutic intervention of NK cells in tumor immunotherapy.
Project description:Enfortumab vedotin is a Nectin-4-directed antibody–drug conjugate designed to deliver the microtubule-disrupting agent monomethyl auristatin E (MMAE) in tumor cells. Using preclinical models of urothelial cancer (UC), we expand the understanding of the multifaceted mechanism of action for enfortumab vedotin that includes direct cytotoxicity on Nectin-4–positive tumor cells, indirect bystander effect on neighboring Nectin-4–negative tumor cells, and MMAE-mediated induction of immunogenic cell death (ICD) and associated increase in activated immune cells in the tumor microenvironment. Importantly, vaccination with enfortumab vedotin-treated tumor cells drives antitumor immunity and provides protection against rechallenge in mice. MMAE-mediated ICD induction modulates the tumor microenvironment in a complementary manner to immune checkpoint inhibition. Accordingly, enfortumab vedotin plus PD-1 inhibitor shows enhanced antitumor activity in vivo. These preclinical results demonstrate the underlying mechanisms consistent with the significantly improved clinical outcomes observed for enfortumab vedotin plus pembrolizumab relative to chemotherapy in the first-line treatment of la/mUC.