Spheroids were grown at 37C for 14 days

Spheroids were grown at 37C for 14 days. a strong inhibitory potential versus the thousand-and-one amino acid kinase 3 (TAOK3), CDK7, and aurora B kinases. We found that cells grown under CSC-enriching spheroid conditions are selectively dependent on TAOK3 signaling. Loss of TAOK3 decreases colony formation, expression of stem cell markers, and sensitizes spheroids to the genotoxic Parimifasor effect of gemcitabine whereas overexpression of TAOK3 increases stem cell traits including tumor initiation and metastasis formation. By inactivating multiple components of the cell cycle machinery in concert with the down-regulation of key CSC signatures, inhibitor #1 defines a distinctive strategy for targeting pancreatic cancer cell populations. Introduction Pancreatic cancer currently ranks 4th among all cancer-related deaths in the U. S and is estimated to rank second by the year 2030.1,2 The 5-year survival rate of the disease is ~5% and has not significantly changed over the last three decades. Early systemic spread and insurmountable drug resistance are the primary drivers of these dismal outcomes.3 Patients who undergo surgical resection inevitably recur with Parimifasor metastases to the liver, lungs, and peritoneum due to preexisting micrometastases which evade eradication by adjuvant systemic chemotherapy. Current systemic chemotherapy regimens extend median overall survival by 4.3 and 1.8 months relative to single agent gemcitabine therapy.4,5 These incremental gains underscore the Parimifasor dire need for alternate approaches to treating this disease. Improved insights into tumoral heterogeneity has supported the concept of progenitor-like cancer cells often referred to as cancer stem cells (CSC). These populations of less differentiated cells maintain the ability to self-renew and are drivers for therapeutic resistance and rapid recurrence.6,7 CSCs are postulated to reside in specific niches characterized by low oxygen tension, limited nutrient supply, and high redox load.8,9 CSCs are highly protective of their genome via upregulation of a variety of DNA damage repair (DDR) mechanisms and fail to undergo programmed cell death or enter senescence upon treatment with genotoxic agents.7,10 These cells exaggerate key DDR mechanisms including accelerated homologous recombination (HR), non-homologous end joining (NHES), ATR- and ATM-mediated cell cycle checkpoint regulation, or metabolic reprogramming.11C16 Selectively targeting CSC, alone or in combination with cytotoxic agents, as Rabbit polyclonal to ADAMTS3 a means to produce durable remissions is an appealing Parimifasor concept. Recently, both homogenous spheroid models and organoid models have been advanced into drug screening studies in hopes of better targeting these CSC subpopulations to provide more appropriate leads for clinical translation.17,18 In drug screening models, only cellular spheroids represent reliable high-throughput-screening (HTS)-compatible models that consistently demonstrate an up-regulation of known CSC markers and capture tumoral cell heterogeneity and microenvironmental factors.6,19C23 For most next-generation therapies, system-guided target deconvolution of HTS-derived hits is required to enable a complete mechanism-to-phenotype understanding.24,25 Many effective oncology drugs originally discovered for one target were ultimately found to harbor a distinct polypharmacology profile essential to mediate anti-tumor activity.26,27 Understanding the drivers of drug actions can improve the probability of identifying synergistic and additive drug combinations and further the chances of finding effective drug/drug combinations capable to targeting otherwise drug-resistant cancer cell populations.25 Here, we describe the identification of a previously reported small molecule inhibitor of the interleukin-2-inducible T-cell kinase (ITK) (NCGC00188382, inhibitor #1) as an agent with pan-killing of the spheroid harboring CSC features and 2D monolayer phenotype of pancreatic cancer cells.28 The compound effectively induces apoptosis in spheroid cultures, inhibits invasion,.