Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer characterized by late diagnosis and extensive metastasis. It is known to contain exclusively tumorigenic cancer stem cells (CSCs), which are resistant to chemotherapy like gemcitabine. We have previously shown that CD133+ CSCs contributes to disease progression and treatment failure in PDAC. In this study we demonstrate the therapeutic potential of novel dual BET/HDAC inhibitor TW09 to target CD133+ CSCs in a preclinical set-up.
shRNA mediated knockdown of cMyc was performed to delineate the downstream effectors and signaling pathways. Gene set enrichment analysis (GSEA) analysis was performed on TW09 and control treated pancreatic cancer cells to analyse CSC metabolism and growth. FACS sorting, qPCR, western blot and MTT assay characterized dose dependent effects on different patient-derived pancreatic cancer cell lines. Post TW09 treatment, sphere formation assay and CD133 surface staining determined the role on self-renewal capacity whereas, Annexin V and EdU staining delineated CSC specific signaling modulation. Additionally, organoid treatment using gemcitabine, TW09 and combination was performed to describe their therapeutic potential.
GSEA revealed that the significantly enriched pathways involved in metabolism and OXPHOS were downregulated by TW09 in comparison to control. In addition, TW09 decreased gene expression of CSC, pluripotency and EMT related markers. TW09 negatively modulated CD133+ & ALDH+ population as well as sphere formation capacity confirming its strong CSC inhibiting property. CD133+ population specific loss of mitochondrial membrane potential, G2M arrest and apoptosis was also observed. Furthermore, organoid treatment uncovered that TW09 can sensitize resistant cells towards gemcitabine.
We elucidate here the deregulation of different molecular pathways involved in CSC maintenance, pluripotency and EMT using TW09 on primary PDAC cell lines. We also describe that TW09 shows cancer stem cell specific apoptosis and metabolic changes. We depict, in a preclinical set up, that TW09 has potent anti-tumor activity by selectively targeting CSCs and represents as a prospective therapeutic strategy for PDAC.
The authors.
Plasticity in Pancreatic Ductal Adenocarcinomas (PiPAC).
All authors have declared no conflicts of interest.