Stem Cell Models for Breast and Colon Cancer: Experimental Approach for Drug Discovery

APOA5 alleviates reactive oxygen species to promote oxaliplatin resistance in PIK3CA-mutated colorectal cancer

Although platinum-based chemotherapy is the frontline regimen for colorectal cancer (CRC), drug resistance remains a major challenge affecting its therapeutic efficiency. However, there is limited research on the correlation between chemotherapy resistance and lipid metabolism, including PIK3CA mutant tumors. In this present study, we found that PIK3CA-E545K mutation attenuated cell apoptosis and increased the cell viability of CRC with L-OHP treatment in vitro and in vivo. Mechanistically, PIK3CA-E545K mutation promoted the nuclear accumulation of SREBP1, which promoted the transcription of Apolipoprotein A5 (APOA5). APOA5 activated the PPARγ signaling pathway to alleviate reactive oxygen species (ROS) production following L-OHP treatment, which contributed to cell survival of CRC cells. Moreover, APOA5 overexpression enhanced the stemness-related traits of CRC cells. Increased APOA5 expression was associated with PIK3CA mutation in tumor specimens and poor response to first-line chemotherapy, which was an independent detrimental factor for chemotherapy sensitivity in CRC patients. Taken together, this study indicated that PIK3CA-E545K mutation promoted L-OHP resistance by upregulating APOA5 transcription in CRC, which could be a potent target for improving L-OHP chemotherapeutic efficiency. Our study shed light to improve chemotherapy sensitivity through nutrient management in CRC.

Kurarinone targets JAK2-STAT3 signaling in colon cancer-stem-like cells

Natural compounds are known to regulate stemness/self-renewal properties in colon cancer cells at molecular level. In the present study, we first time studied the colon cancer stem-like cells targeting potential of Kurarinone (KU) and explored the underlying mechanism. Cytotoxic potential of KU was checked in colon cancer cells. Colonosphere formation assay was performed to check the spheroid formation reduction potential of KU in HCT-116 cells by using phase-contrast microscopy. Stemness/self-renewal marker expression was studied at mRNA and protein levels in colonosphere. The qRT-PCR, western blot analysis, and flow cytometer techniques were used to assess the effect of KU treatment on cell cycle progression and apoptosis induction in colon cancer cells and colonosphere. Further, effect of KU treatment on pSTAT3 status and its nuclear translocation was also studied. KU treatment significantly decreased HCT-116 cell proliferation and reduced sphere formation potential at IC30 (8.71 µM) and IC50 (20.34 µM) concentrations compared to respective vehicle-treated groups, respectively. KU exposure significantly reduced the expression of CD44, c-Myc, Bmi-1, and Sox2 stemness/self-renewal markers in colonosphere in a dose-dependent manner. KU treatment inhibits JAK2-STAT3 signaling pathway by reducing pSTAT3 levels and its nuclear translocation in HCT-116 cells and colonosphere at IC50 concentration. KU treatment significantly decreased the expression of CCND1 and CDK4 cell cycle-specific markers and arrested the HCT-116 cells and colonosphere in G1-phase. Further, KU treatment increased Bax/Bcl-2 ratio, apoptotic cell population, cleaved caspase 3, and PARP-1 in HCT-116 cells and colonosphere. In conclusion, KU treatment decreases stemness/self-renewal, induces cell cycle arrest and apoptosis in HCT-116 colonosphere by down-regulating CD44-JAK2-STAT3 axis. Thus, targeting stemness/self-renewal and other cancer hallmark(s) by KU through CD44/JAK2/STAT3 signaling pathway might be a novel strategy to target colon cancer stem-like cells.

The Role of Tumor Stem Cells in Colorectal Cancer Drug Resistance

Background: Colorectal cancer is a major cause of mortality among the prevalent malignant tumors of the gastrointestinal tract. Although chemotherapy is a standard treatment for colorectal cancer, its efficacy is limited by chemoresistance. Recent studies have investigated targeting tumor stem cells as a potential new therapeutic approach for addressing chemoresistance in colorectal cancer. Colorectal cancer frequently relapses, with tumor stem cells often representing one of the leading causes of treatment failure. Purpose: Understanding drug resistance in colorectal cancer stem cells is crucial for improving treatment outcomes. By focusing on developing targeted therapies that specifically address drug resistance in colorectal cancer stem cells, there is potential to make significant advancements in the treatment of colorectal cancer.This approach may lead to more effective and lasting outcomes in patients battling colorectal cancer. Research Design: In this review, a comprehensive overview of recent research on colorectal cancer stem cell treatment resistance is presented.Results: Elucidating the key underlying mechanisms. This review also highlights the potential benefits of targeted therapies in overcoming colorectal cancer resistance to treatment. Conclusions: CCSCs are key players in drug resistance of CRC, indicating their potential as targets for effective therapy. Elucidating their role in this process could aid in discovering tailored treatment strategies.The significance of signaling pathways, TME, and miRNA in regulating drug resistance in CCSCs is been highlighted.

From resistance to resilience: Uncovering chemotherapeutic resistance mechanisms; insights from established models

Despite the tremendous advances in cancer treatment, resistance to chemotherapeutic agents impedes higher success rates and accounts for major relapses in cancer therapy. Moreover, the resistance of cancer cells to chemotherapy is linked to low efficacy and high recurrence of cancer. To stand up against chemotherapy resistance, different models of chemotherapy resistance have been established to study various molecular mechanisms of chemotherapy resistance. Consequently, this review is going to discuss different models of induction of chemotherapy resistance, highlighting the most common mechanisms of cancer resistance against different chemotherapeutic agents, including overexpression of efflux pumps, drug inactivation, epigenetic modulation, and epithelial-mesenchymal transition. This review aims to open a new avenue for researchers to lower the resistance to the existing chemotherapeutic agents, develop new therapeutic agents with low resistance potential, and establish possible prognostic markers for chemotherapy resistance.