FOLFOXIRI plus biologics in advanced colorectal cancer

Baicalein triggers ferroptosis in colorectal cancer cells via blocking the JAK2/STAT3/GPX4 axis

Colorectal cancer (CRC) is a prevalent form of gastrointestinal malignancy with challenges in chemotherapy resistance and side effects. Effective and low toxic drugs for CRC treatment are urgently needed. Ferroptosis is a novel mode of cell death, which has garnered attention for its therapeutic potential against cancer. Baicalein (5, 6, 7-trihydroxyflavone) is the primary flavone extracted from the dried roots of Scutellaria baicalensis that exhibits anticancer effects against several malignancies including CRC. In this study, we investigated whether baicalein induced ferroptosis in CRC cells. We showed that baicalein (1-64 μM) dose-dependently inhibited the viability of human CRC lines HCT116 and DLD1. Co-treatment with the ferroptosis inhibitor liproxstatin-1 (1 μM) significantly mitigated baicalein-induced CRC cell death, whereas autophagy inhibitor chloroquine (25 μM), necroptosis inhibitor necrostatin-1 (10 μM), or pan-caspase inhibitor Z-VAD-FMK (10 μM) did not rescue baicalein-induced CRC cell death. RNA-seq analysis confirmed that the inhibitory effect of baicalein on CRC cells is associated with ferroptosis induction. We revealed that baicalein (7.5-30 μM) dose-dependently decreased the expression levels of GPX4, key regulator of ferroptosis, in HCT116 and DLD1 cells by blocking janus kinase 2 (JAK2)/STAT3 signaling pathway via direct interaction with JAK2, ultimately leading to ferroptosis in CRC cells. In a CRC xenograft mouse model, administration of baicalein (10, 20 mg/kg, i.g., every two days for two weeks) dose-dependently inhibited the tumor growth with significant ferroptosis induced by inhibiting the JAK2/STAT3/GPX4 axis in tumor tissue. This study demonstrates that ferroptosis contributes to baicalein-induced anti-CRC activity through blockade of the JAK2/STAT3/GPX4 signaling pathway, which provides evidence for the therapeutic application of baicalein against CRC.

Diphenyl ditelluride anticancer activity and DNA topoisomerase I poisoning in human colon cancer HCT116 cells

Diphenyl ditelluride (DPDT) is an organotellurium (OT) compound with pharmacological properties, including antioxidant, antigenotoxic and antimutagenic activities when applied at low concentrations. However, DPDT as well as other OT compounds also show cytotoxicity against mammalian cells when treatments occur at higher drug concentrations. Considering that the underlying mechanisms of toxicity of DPDT against tumor cells have been poorly explored, the objective of our study was to investigate the effects of DPDT against both human cancer and non-tumorigenic cells. As a model, we used the colonic HCT116 cancer cells and the MRC5 fibroblasts. Our results showed that DPDT preferentially targets HCT116 cancer cells when compared to MRC5 cells with IC₅₀ values of 2.4 and 10.1 μM, respectively. This effect was accompanied by the induction of apoptosis and a pronounced G2/M cell cycle arrest in HCT116 cells. Furthermore, DPDT induces DNA strand breaks at concentrations below 5 μM in HCT116 cells and promotes the occurrence of DNA double strand breaks mostly during S-phase as measured by γ-H2AX/EdU double staining. Finally, DPDT forms covalent complexes with DNA topoisomerase I, as observed by the TARDIS assay, with a more prominent effect observed in HCT116 than in MRC5 cells. Taken together, our results show that DPDT preferentially targets HCT116 colon cancer cells likely through DNA topoisomerase I poisoning. This makes DPDT an interesting molecule for further development as an anti-proliferative compound in the context of cancer.

Research progress of traditional Chinese medicine as sensitizer in reversing chemoresistance of colorectal cancer

In recent years, the incidences and mortalities from colorectal cancer (CRC) have been increasing; therefore, there is an urgent need to discover newer drugs that enhance drug sensitivity and reverse drug tolerance in CRC treatment. With this view, the current study focuses on understanding the mechanism of CRC chemoresistance to the drug as well as exploring the potential of different traditional Chinese medicine (TCM) in restoring the sensitivity of CRC to chemotherapeutic drugs. Moreover, the mechanism involved in restoring sensitivity, such as by acting on the target of traditional chemical drugs, assisting drug activation, increasing intracellular accumulation of anticancer drugs, improving tumor microenvironment, relieving immunosuppression, and erasing reversible modification like methylation, have been thoroughly discussed. Furthermore, the effect of TCM along with anticancer drugs in reducing toxicity, increasing efficiency, mediating new ways of cell death, and effectively blocking the drug resistance mechanism has been studied. We aimed to explore the potential of TCM as a sensitizer of anti-CRC drugs for the development of a new natural, less-toxic, and highly effective sensitizer to CRC chemoresistance.

LncRNA XIST/miR-137 axis strengthens chemo-resistance and glycolysis of colorectal cancer cells by hindering transformation from PKM2 to PKM1

BACKGROUND

Glycolysis was an essential driver of chemo-resistance in colorectal cancer (CRC), albeit with limited molecular explanations.

OBJECTIVE

We strived to elucidate the involvement of lncRNA XIST/miR-137/PKM axis in chemo-tolerance and glycolysis of CRC.

METHODS

Altogether 212 pairs of tumor tissues and adjacent normal tissues were collected from CRC patients. Moreover, human CRC epithelial cell lines, including HT29, SW480, SW620 and LoVo, were purchased in advance, and their activity was estimated after transfection of si-XIST or miR-137 mimic. Furthermore, 5-FU/cisplatin-resistance of CRC cells was determined through MTT assay, and glycolytic potential of CRC cells was appraised based on oxygen consumption rate (OCR) and extracellular acidification rate (ECAR).

RESULTS

Highly-expressed XIST were predictive of severe symptoms and unfavorable 3-year survival of CRC patients (P< 0.05). Besides, silencing of XIST not only diminished proliferative, migratory and invasive power of CRC cells (P< 0.05), but also enhanced sensitivity of CRC cells responding to 5-FU/cisplatin (P< 0.05). Glycolytic potency of CRC cells was also undermined by si-XIST, with decreased maximal respiration and maximal glycolytic capacity in the si-XIST group as relative to NC group (P< 0.05). Nevertheless, miR-137 mimic attenuated the facilitating effect of pcDNA3.1-XIST on proliferation, migration, invasion, 5-FU/cisplatin-resistance and glycolysis of CRC cells (P< 0.05). Ultimately, ratio of PKM2 mRNA and PKM1 mRNA, despite being up-regulated by pcDNA3.1-XIST, was markedly lowered when miR-137 mimic was co-transfected (P< 0.05).

CONCLUSIONS

LncRNA XIST/miR-137 axis reinforced glycolysis and chemo-tolerance of CRC by elevating PKM2/PKM1 ratio, providing an alternative to boost chemo-therapeutic efficacy of CRC patients.