佐谷 秀行

BACKGROUND: Benzaldehyde (BA) is an aromatic aldehyde found in fruits that has been studied as a potential anticancer agent on the basis of its ability to inhibit transformation in mouse embryo cells and to suppress metastasis in mice. METHODS: We investigated the cytotoxic effects of BA on cancer cells, and probed its effects on intracellular signaling pathways. The anticancer effects of BA in vivo were studied by using a mouse orthotopic transplantation model of pancreatic cancer. RESULTS: BA inhibited the growth of osimertinib- or radiation-resistant cancer cells as well as the interaction between 14-3-3ζ and its client proteins. The interaction of 14-3-3ζ with the Ser28-phosphorylated form of histone H3 (H3S28ph) was implicated in treatment resistance and the transcriptional regulation of genes related to epithelial-mesenchymal transition and stemness, including E2F2, SRSF1, and ID1. Treatment of mice with a BA derivative inhibited pancreatic tumor growth and lung metastasis, as well as suppressed a state of epithelial-mesenchymal plasticity (EMP) of tumor cells. CONCLUSION: The interaction between 14-3-3ζ and H3S28ph plays a key role in EMP and treatment resistance in cancer. The ability of BA to inhibit this and other interactions of 14-3-3ζ offers the potential to overcome treatment resistance and to suppress metastasis.

Abstract CD44, a multifunctional cell surface protein, has emerged as a pivotal regulator in cancer stem cell (CSC) biology, orchestrating processes such as stemness, metabolic reprogramming, and therapeutic resistance. Recent studies have identified a critical role of CD44 in ferroptosis resistance by stabilizing SLC7A11 (xCT), a key component of the antioxidant defense system, enabling CSCs to evade oxidative stress and sustain tumorigenic potential. Additionally, CD44 regulates intracellular iron metabolism and redox balance, further supporting CSC survival and adaptation to stressful microenvironments. Therapeutic strategies targeting CD44, including ferroptosis inducers and combination therapies, have shown significant potential in preclinical and early clinical settings. Innovations such as CD44-mediated nanocarriers and metabolic inhibitors present novel opportunities to disrupt CSC-associated resistance mechanisms. Furthermore, the dynamic plasticity of CD44 isoforms governed by transcriptional, post-transcriptional, and epigenetic regulation underscores the importance of context-specific therapeutic approaches. This review highlights the multifaceted roles of CD44 in CSC biology, focusing on its contribution to ferroptosis resistance, iron metabolism, and redox regulation. Targeting CD44 offers a promising avenue for overcoming therapeutic resistance and improving the outcomes of refractory cancers. Future studies are needed to refine these strategies and enable their clinical translation.

Background/Objective: Ovarian cancer (OC) is one of the most lethal gynecological cancers, having a worldwide mortality rate of 66% in 2020. The overall 5-year relative survival rate is only 21% for distant stages, due to the lack of early diagnosis. Epithelial OC, the most common high-grade serous carcinoma, carries p53 mutations in most cases. However, we found that the immediate early response 5 gene (IER5), a p53 target gene, is overexpressed in ovarian cancer cells. The molecular mechanism underlying the role of IER5 in OC has not been well studied. We previously reported that IER5 promotes the dephosphorylation and activation of heat shock factor-1 (HSF1), the master regulator of proteostasis, which induces heat shock protein (HSP) expression. Methods/Results: Here we show that Ier5 mRNA expression is higher in ovarian cancer cells (MOV, ID8G, and HM-1) compared to normal ovarian cells. We also show that OC cells floating in the ascites have higher Ier5 expression than the parental strain. Knockdown of Ier5 suppressed HSP upregulation and proliferation of OC, while overexpression of IER5 promoted HSP upregulation. Knockdown of Hsf1 showed results similar to Ier5 knockdown. Conclusions: These results indicate that the IER5-HSF1 pathway contributes to the proliferation and peritoneal dissemination of OC cells. We also found that higher expression of IER5 family genes is related to poorer prognosis of OC patients, suggesting the potential of the IER5 gene family as diagnostic markers for OC, as well as potential therapeutic targets.

BACKGROUND: Colorectal cancer (CRC) is a substantial global health concern due to its limited treatment options, especially for oxaliplatin (L-OHP) regimen resistance. This study used organoid-based screening methodologies to evaluate drug responses in CRC while validating the approach with patient-derived CRC organoids and investigating potential biomarkers. METHODS: Patient-derived organoids were created from CRC surgical specimens, and drug screening were performed. Selected organoids with high and low L-OHP sensitivity underwent next-generation sequencing (NGS), and in vivo experiments using xenotransplantation were used to validate in vitro results. Moreover, the clinical application of homologous recombination deficiency (HRD) as a biomarker was investigated. RESULTS: Organoid drug screening revealed differences in L-OHP sensitivity among 34 patient-derived CRC organoids, and NGS deemed HRD as a potential biomarker. In vivo experiments validated the correlation between HRD status and L-OHP sensitivity, and clinical data suggested the potential of HRD as a biomarker for recurrence-free survival in patients treated with L-OHP. Additionally, HRD exhibited potential as a biomarker for other platinum agents and poly (ADP-ribose) polymerase inhibitors in CRC. CONCLUSIONS: The study underscores HRD as a potential biomarker for predicting L-OHP sensitivity, expanding its application to other drugs in CRC. Organoid screening is reliable, providing insights into the intricate association between genetic features and treatment responses.

Developmental toxicity testing is essential to identify substances that may harm embryonic development. This study aimed to establish a protocol for evaluating developmental toxicity using human induced pluripotent stem cells (iPSCs) by analyzing cellular activity and gene expression changes. Two ICH S5(R3) positive substances, valproic acid (VPA), which is a substance previously detected as positive by other test methods, and thalidomide (Thalido), were examined during early trichoderm differentiation without fetal bovine serum. RNA-seq analysis identified seven candidate genes, including TP63, associated with altered expression following exposure to VPA or Thalido. These genes were implicated in pathways related to tissue development, cell growth, and molecular interactions. While the assay effectively detected VPA and Thalido, its limitations include testing only soluble substances and focusing on early differentiation stages. Nevertheless, the protocol demonstrates potential for the classification and evaluation of emerging modality drugs based on physical properties such as solubility, polarity, and pH. Integration with AI analysis may enhance its capacity to uncover genetic variations and evaluate previously uncharacterized substances. This study provides a foundation for alternative developmental toxicity testing methods, with further refinements in the culture method expected to improve accuracy and applicability in regulatory toxicology.