First-line nivolumab plus ipilimumab with or without chemotherapy for Japanese patients with non-small cell lung cancer: LIGHT-NING study.

OBJECTIVE: As first-line treatment for stage IV or recurrent non-small cell lung cancer, combination immunotherapy with nivolumab and ipilimumab, with or without chemotherapy, had demonstrated survival benefits over chemotherapy; however, data on Japanese patients are limited. METHODS: LIGHT-NING was a multicenter, observational study and retrospectively collected data. In this interim analysis, we analyzed patients who received combination immunotherapy between 27 November 2020 and 31 August 2021 for the treatment status, safety objectives (treatment-related adverse events and immune-related adverse events incidences), and effectiveness objectives (objective response rate and progression-free survival) to determine the characteristics and early safety information. RESULTS: We analyzed 353 patients, with a median follow-up of 7.1 (interquartile range, 5.0-9.7) months. Overall, 60.1 and 39.9% received nivolumab plus ipilimumab with and without chemotherapy, respectively. In these cohorts, the median age was 67 and 72 years; 10.8 and 35.5% were aged ≥75 years; 80.2 and 79.4% were male; 5.2 and 13.5% had a performance score ≥ 2; 32.1 and 27.0% developed grade 3-4 immune-related adverse events; treatment-related deaths were observed in 6 (2.8%) and 5 (3.5%) patients, respectively. Grade 3-4 immune-related adverse event incidence was the highest within the first month of treatment in both cohorts, although the immune-related adverse event risk persisted throughout. No new safety signals were observed at this interim analysis. The median progression-free survival was 6.0 (95% confidence interval, 5.2-7.6) and 5.8 (4.3-7.0) months in nivolumab plus ipilimumab with and without chemotherapy cohorts, respectively. CONCLUSIONS: LIGHT-NING offers valuable insights into combination immunotherapy for untreated patients with stage IV or recurrent non-small cell lung cancer in Japanese real-world settings.

Identification of FERM domain-containing protein 5 as a novel target of ß-catenin/TCF7L2 complex.

Deregulation of the canonical Wnt signaling pathway plays an important role in human tumorigenesis through the accumulation of ß-catenin and subsequent transactivation of TCF7L2. Although some of the consequences associated with the accumulated ß-catenin have been clarified, the comprehensive effect of activated ß-catenin/TCF7L2 transcriptional complex on tumorigenesis remains to be elucidated. To understand the precise molecular mechanisms underlying colorectal cancer, we searched for genes regulated by the complex in colorectal tumors. We performed expression profile analysis of HCT116 and SW480 colon cancer cells treated with ß-catenin siRNAs, and ChIP-sequencing using anti-TCF7L2 antibody. Combination of these data with public microarray data of LS174 cells with a dominant-negative form of TCF7L2 identified a total of 11 candidate genes. In this paper, we focused on FERM domain-containing protein 5 (FRMD5), and confirmed that it is regulated by both ß-catenin and TCF7L2. An additional reporter assay disclosed that a region in intron1 transcriptionally regulated the expression of FRMD5. ChIP assay also corroborated that TCF7L2 associates with this region. These data suggested that FRMD5 is a novel direct target of the ß-catenin/TCF7L2 complex.

Bidirectional reporter assay using HAL promoter and TOPFLASH improves specificity in high-throughput screening of Wnt inhibitors.

Constitutive activation of Wnt signaling plays an important role in colorectal and liver tumorigenesis. Cell-based assays using synthetic TCF/LEF (T-cell factor/lymphoid enhancer factor) reporters, as readouts of ß-catenin/TCF-dependent transcriptional activity, have contributed greatly to the discovery of small molecules that modulate Wnt signaling. In the present study, we report a novel screening method, called a bidirectional dual reporter assay. Integrated transcriptome analysis identified a histidine ammonia-lyase gene (HAL) that was negatively regulated by ß-catenin/TCF-dependent transcriptional activity. We leveraged a promoter region of the HAL gene as another transcriptional readout of Wnt signaling. Cells stably expressing both an optimized HAL reporter and the TCF/LEF reporter enabled bidirectional reporter activities in response to Wnt signaling. Increased HAL reporter activity and decreased TCF/LEF reporter activity were observed simultaneously in the cells when ß-catenin/TCF7L2 was inhibited. Notably, this method could decrease the number of false positives observed when screening an inhibitor library compared with the conventional TCF/LEF assay. We found that Brefeldin A, a disruptor of the Golgi apparatus, inhibited the Wnt/ß-catenin signaling pathway. The utility of our system could be expanded to examine other disease-associated pathways beyond the Wnt/ß-catenin signaling pathway.

Anti-apoptotic effect by the suppression of IRF1 as a downstream of Wnt/ß-catenin signaling in colorectal cancer cells.

Impaired Wnt signaling pathway plays a crucial role in the development of colorectal cancer through activation of the ß-catenin/TCF7L2 complex. Although genes upregulated by Wnt/ß-catenin signaling have been intensively studied, the roles of downregulated genes are poorly understood. Previously, we reported that interferon-induced proteins with tetratricopeptide repeats 2 (IFIT2) was downregulated by the Wnt/ß-catenin signaling, and that the suppressed expression of IFIT2 conferred antiapoptotic property to colorectal cancer (CRC) cells. However, the mechanisms underlying how Wnt/ß-catenin signaling regulates IFIT2 remain to be elucidated. In this study, we have uncovered that the expression of IFIT2 is induced by IRF1, which is negatively regulated by the Wnt/ß-catenin signaling. In addition, we found that downregulation of IRF1 is mediated by its degradation through the ubiquitination-proteasome pathway, and that decreased activity of a deubiquitinase complex containing USP1 and UAF1 is involved in the degradation of IRF1 by Wnt/ß-catenin signaling. These data should provide better understanding of the Wnt signaling pathway and human carcinogenesis.

Establishment and analysis of a novel mouse line carrying a conditional knockin allele of a cancer-specific FBXW7 mutation.

F-box and WD40 domain protein 7 (FBXW7) is a component of the SKP1-CUL1-F-box protein (SCF) complex that mediates the ubiquitination of diverse oncogenic target proteins. The exploration of FBXW7 mutations in human primary cancer has revealed three mutation hotspots at conserved arginine residues (Arg465, Arg479, and Arg505) in the WD40 domain, which are critical for substrate recognition. To study the function of human FBXW7 R465C , the most frequent mutation in human malignancies, we generated a novel conditional knockin mouse line of murine Fbxw7 R468C corresponding to human FBXW7 R465C . Systemic heterozygous knockin of the Fbxw7 R468C mutation resulted in perinatal lethality due to defects in lung development, and occasionally caused an eyes-open at birth phenotype and cleft palate. Furthermore, mice carrying liver-specific heterozygous and homozygous Fbxw7 R468C alleles cooperated with an oncogenic Kras mutation to exhibit bile duct hyperplasia within 8 months of birth and cholangiocarcinoma-like lesions within 8 weeks of birth, respectively. In addition, the substrates affected by the mutant Fbxw7 differed between the embryos, embryonic fibroblasts, and adult liver. This novel conditional knockin Fbxw7 R468C line should be useful to gain a more profound understanding of carcinogenesis associated with mutation of FBXW7.

Decreased expression of interferon-induced protein 2 (IFIT2) by Wnt/ß-catenin signaling confers anti-apoptotic properties to colorectal cancer cells.

Impaired Wnt signaling pathway plays a crucial role in the development of colorectal cancer through activation of the ß-catenin/TCF7L2 complex. Although genes up-regulated by Wnt/ß-catenin signaling have been intensively studied, the roles of down-regulated genes are poorly understood. In this study, we explored a global gene expression of colorectal cancer cells transfected with ß-catenin siRNAs or a dominant negative form of TCF7L2 (dnTCF7L2), and identified a set of genes down-regulated by Wnt/ß-catenin signaling. Among the genes, we focused here on IFIT2, a gene encoding interferon-induced protein with tetratricopeptide repeats. A reporter assay using plasmids containing a 5'-flanking region of the gene showed that the reporter activity was enhanced by either transduction of ß-catenin siRNA or dnTCF7L2, suggesting that the region is involved in the transcriptional regulation as a downstream of the ß-catenin/TCF7L2 complex. Consistent with this result, expression of IFIT2 was significantly lower in colorectal cancer tissues than that in normal tissues. Exogenous IFIT2 expression decreased cell proliferation and increased apoptosis of colorectal cancer cells. These data suggested that the down-regulation of IFIT2 by Wnt/ß-catenin signaling may play a vital role in human colorectal carcinogenesis through the suppression of apoptosis.