5-Fluorouracil (5-FU) remains the first-line treatment for colorectal cancer (CRC). Although 5-FU initially de-bulks the tumor mass, recurrence after chemotherapy is the barrier to effective clinical outcomes for CRC patients. Here, we demonstrate that p53 promotes WNT3 transcription, leading to activation of the WNT/β-catenin pathway in Apc^Min/+/Lgr5^EGFP mice, CRC patient-derived tumor organoids (PDTOs) and patient-derived tumor cells (PDCs). Through this regulation, 5-FU induces activation and enrichment of cancer stem cells (CSCs) in the residual tumors, contributing to recurrence after treatment. Combinatorial treatment of a WNT inhibitor and 5-FU effectively suppresses the CSCs and reduces tumor regrowth after discontinuation of treatment. These findings indicate p53 as a critical mediator of 5-FU-induced CSC activation via the WNT/β-catenin signaling pathway and highlight the significance of combinatorial treatment of WNT inhibitor and 5-FU as a compelling therapeutic strategy to improve the poor outcomes of current 5-FU-based therapies for CRC patients.

Differential chemo-sensitivity of cancer cells, which is attributed to the cellular heterogeneity and phenotypic variation of cancer cells, is considered to be the main reason for tumor recurrence after chemotherapy. Here, we generated small cell lung cancer patient-derived tumor organoids and subjected them to long-term expansion with the addition of WNT3A or R-spondin1. We confirmed that the organoids have similar genetic profiles, molecular characteristics, and morphological architectures to the corresponding patient tumor tissue during and after long-term expansion. Interestingly, the cellular heterogeneity of organoids is reflected in their differential response to cisplatin or etoposide. We propose to utilize the organoids as small cell lung cancer patient avatar models that would be ideal for investigating the mechanisms underlying tumor recurrence after chemotherapy, and would ultimately help to develop personalized medicine.

Purpose The aim of this study is to evaluate the safety and efficacy of ex vivo activated and expanded natural killer (NK) cell therapy (SNK01) plus pembrolizumab in a randomized phase I/IIa clinical trial.Materials and Methods Overall, 18 patients with advanced non–small cell lung cancer (NSCLC) and a programmed death ligand 1 tumor proportion score of 1% or greater who had a history of failed frontline platinum-based therapy were randomized (2:1) to receive pembrolizumab every 3 weeks +/– 6 weekly infusions of SNK01 at either 2×109 or 4×109 cells per infusion (pembrolizumab monotherapy vs. SNK01 combination). The primary endpoint was safety, whereas the secondary endpoints were the objective response rate (ORR), progression-free survival (PFS), overall survival, and quality of life.Results Since no dose-limiting toxicity was observed, the maximum tolerated dose was determined as SNK01 4×109 cells/dose. The safety data did not show any new safety signals when SNK01 was combined with pembrolizumab. The ORR and the 1-year survival rate in the NK combination group were higher than those in patients who underwent pembrolizumab monotherapy (ORR, 41.7% vs. 0%; 1-year survival rate, 66.7% vs. 50.0%). Furthermore, the median PFS was higher in the SNK01 combination group (6.2 months vs. 1.6 months, p=0.001).Conclusion Based on the findings of this study, the NK cell combination therapy may consider as a safe treatment method for stage IV NSCLC patients who had a history of failed platinum-based therapy without an increase in adverse events.

Background: Cancer stem cells (CSCs), the major driver of tumorigenesis, is a sub-population of tumor cells responsible for poor clinical outcomes. However, molecular mechanism to identify targets for controlling CSCs is poorly understood. Methods: Gene Set Enrichment Analyses (GSEA) of Wnt/β-catenin and RAS signaling pathways in stem-like subtype of colorectal cancer (CRC) patients were performed using two gene expression data set. The therapeutic effects of destabilization of β-catenin and RAS were tested by treatment of small molecule KYA1797K using CRC patient derived cells. Results: Treatment with KYA1797K, a small molecule that destabilizes both β-catenin and RAS via Axin binding, effectively suppresses the stemness of CSCs as shown in CRC spheroids and small intestinal tumors of Apc^Min/+/K-Ras^G12DLA2 mice. Moreover, KYA1797K also suppresses the stemness of cells in CRC patient avatar model systems, such as patient-derived tumor organoids (PDTOs) and patient-derived tumor xenograft (PDTX). Conclusion: Our results suggest that destabilization of both β-catenin and RAS is a potential therapeutic strategy for controlling stemness of CRC cells.

Kyungtae Lim, Mi-Ok Lee, Jinwook Choi, Jung-Hyun Kim, Eun-Mi Kim, Chang Gyu Woo, Chaeuk Chung, Yong-Hee Cho, Seok-Ho Hong, Young-Jae Cho, Sun-Ju Ahn. IJSC -0001;0:. https://doi.org/10.15283/ijsc24041

Targeted protein degradation (TPD) is a relatively novel drug discovery strategy that could help break through the limitations of traditional small molecule inhibitors. While TPD mostly utilizes diverse E3 ligases to incorporate the ubiquitin‐proteasome system (UPS), cereblon (CRBN) could be considered one of the most successfully adopted E3 ligases. Thus, expanding the scope of CRBN ligands has received tremendous attention to overcome related issues, such as selectivity and druggability. In this study, design and synthesis of novel benzosultam‐based CRBN ligands have been explored by replacement of lactam in lenalidomide with sultam. The sultam‐based ligands showed CRBN binding affinities 2‐20 times stronger than lenalidomide, presumably from additional hydrogen bonds generated from the extra oxygen atom in the sultam group, as supported by docking studies. This research highlights the potential of novel benzosultam CRBN ligands as a new tool for CRBN‐mediated TPD strategies.