Comprehensive assessment of actionable genomic alterations in primary colorectal carcinoma using targeted next-generation sequencing.

BACKGROUND: The clinical utility of comprehensive genomic profiling (CGP) for guiding treatment has gradually become the standard-of-care procedure for colorectal carcinoma (CRC). Here, we comprehensively assess emerging targeted therapy biomarkers using CGP in primary CRC. METHODS: A total of 575 primary CRCs were sequenced by ACTOnco® assay for genomic alterations, tumour mutational burden (TMB), and microsatellite instability (MSI). RESULTS: Eighteen percent of patients were detected as MSI-High (MSI-H), and the remaining cases were classified as microsatellite stable (MSS). Driver mutation prevalence in MSS CRCs were APC (74%), TP53 (67%), KRAS (47%), PIK3CA (21%) and BRAF (13%). The median TMBs for MSI-H and MSS patients were 37.8 mutations per mega base (mut/Mb) and 3.9 mut/Mb, respectively. Forty-seven percent of MSI-H CRC harboured at least one loss-of-function mutations in genes that may hamper immune checkpoint blockade. Among MSS RAS/RAF wild-type CRCs, 59% had at least one actionable mutation that may compromise the efficacy of anti-EGFR therapy. For late-stage CRC, 51% of patients are eligible for standard care actionability and the remaining 49% could be enrolled in clinical trials with investigational drugs. CONCLUSIONS: This study highlights the essential role of CGP for identifying rational targeted therapy options in CRC.

miR-31 is consistently inactivated in EBV-associated nasopharyngeal carcinoma and contributes to its tumorigenesis.

BACKGROUND: As a distinctive type of head and neck cancers, nasopharyngeal carcinoma (NPC) is genesis from the clonal Epstein-Barr virus (EBV)-infected nasopharyngeal epithelial cells accumulated with multiple genetic lesions. Among the recurrent genetic alterations defined, loss of 9p21.3 is the most frequent early event in the tumorigenesis of EBV-associated NPC. In addition to the reported CDKN2A/p16, herein, we elucidated the role of a miRNA, miR-31 within this 9p21.3 region as NPC-associated tumor suppressor. METHODS: The expression and promoter methylation of miR-31 were assessed in a panel of NPC tumor lines and primary tumors. Its in vitro and in vivo tumor suppression function was investigated through the ectopic expression of miR-31 in NPC cells. We also determined the miR-31 targeted genes and its involvement in the growth in NPC. RESULTS: Downregulation of miR-31 expression was detected in almost all NPC cell line, patient-derived xenografts (PDXs) and primary tumors. Both homozygous deletion and promoter hypermethylation were shown to be major mechanisms for miR-31 silencing in this cancer. Strikingly, loss of miR-31 was also obviously observed in the dysplastic lesions of nasopharynx. Restoration of miR-31 in C666-1 cells inhibited the cell proliferation, colony-forming and migratory capacities. Dramatic reduction of in vitro anchorage-independent growth and in vivo tumorigenic potential were demonstrated in the stable clones expressing miR-31. Furthermore, we proved that miR-31 suppressed the NPC cell growth via targeting FIH1 and MCM2. CONCLUSIONS: The findings provide strong evidence to support miR-31 as a new NPC-associated tumor suppressor on 9p21.3 region. The inactivation of miR-31 may contribute to the early development of NPC.

Constitutive activation of distinct NF-κB signals in EBV-associated nasopharyngeal carcinoma.

As a distinct type of head and neck cancer, non-keratinizing nasopharyngeal carcinoma (NPC) is closely associated with EBV infection and massive lymphoid infiltration. The unique histological features suggest that local inflammation plays an important role in NPC tumourigenesis. We comprehensively characterized NF-κB signalling, a key inflammatory pathway which might contribute to the tumourigenesis of this EBV-associated cancer. By EMSA, western blotting, and immunohistochemical staining, constitutive activation of distinct NF-κB complexes, either p50/p50/Bcl3 or p50/RelB, was found in almost all EBV-positive NPC tumours. siRNA or chemical inhibition of NF-κB signalling significantly inhibited the growth of EBV-positive NPC cells C666-1. Gene expression profiling identified a number of NF-κB target genes involved in cell proliferation, apoptosis, immune response, and transcription. We further confirmed that p50 signals modulate the expression of multiple oncogenes (MYB, BCL2), chemokines, and chemokine receptors (CXCL9, CXCL10, CX3CL1, and CCL20). The findings support a crucial role of these constitutively activated NF-κB signals in NPC tumourigenesis and local inflammation. In addition to expression of the viral oncoprotein LMP1, genetic alteration of several NF-κB regulators (eg TRAF3, TRAF2, NFKBIA, A20) also contributes to the aberrant NF-κB activation in EBV-associated NPC. Except for LMP1-expressing C15 cells, all NPC tumour lines harbour at least one of these genetic alterations. Importantly, missense mutations of TRAF3, TRAF2, and A20 were also detected in 3/33 (9.1%) primary tumours. Taken together with the reported LTBR amplification in 7.3% of primary NPCs, genetic alterations in NF-κB pathways occurred in at least 16% of cases of this cancer. The findings indicate that distinct NF-κB signals are constitutively activated in EBV-positive NPC cells by either multiple genetic changes or EBV latent genes.

Crucifera sulforaphane (SFN) inhibits the growth of nasopharyngeal carcinoma through DNA methyltransferase 1 (DNMT1)/Wnt inhibitory factor 1 (WIF1) axis.

BACKGROUND: Sulforaphane (SFN), a natural compound present in cruciferous vegetable, has been shown to possess anti-cancer activities. Cancer stem cell (CSC) in bulk tumor is generally considered as treatment resistant cell and involved in cancer recurrence. The effects of SFN on nasopharyngeal carcinoma (NPC) CSCs have not yet been explored. PURPOSE: The present study aims to examine the anti-tumor activities of SFN on NPC cells with CSC-like properties and the underlying mechanisms. METHODS: NPC cells growing in monolayer culture, CSCs-enriched NPC tumor spheres, and also the NPC nude mice xenograft were used to study the anti-tumor activities of SFN on NPC. The population of cells expressing CSC-associated markers was evaluated using flow cytometry and aldehyde dehydrogenase (ALDH) activity assay. The effect of DNA methyltransferase 1 (DNMT1) on the growth of NPC cells was analyzed by using small interfering RNA (siRNA)-mediated silencing method. RESULTS: SFN was found to inhibit the formation of CSC-enriched NPC tumor spheres and reduce the population of cells with CSC-associated properties (SRY (Sex determining Region Y)-box 2 (SOX2) and ALDH). In the functional study, SFN was found to restore the expression of Wnt inhibitory factor 1 (WIF1) and the effect was accompanied with the downregulation of DNMT1. The functional activities of WIF1 and DNMT1 were confirmed using exogenously added recombinant WIF1 and siRNA knockdown of DNMT1. Moreover, SFN was found to inhibit the in vivo growth of C666-1 cells and enhance the anti-tumor effects of cisplatin. CONCLUSION: Taken together, we demonstrated that SFN could suppress the growth of NPC cells via the DNMT1/WIF1 axis.

Gynostemma pentaphyllum saponins attenuate inflammation in vitro and in vivo by inhibition of NF-κB and STAT3 signaling.

Recent advances in the development of anti-inflammatory agents have improved their therapeutic outcome in inflammatory bowel disease (IBD), however, the presence of side effects and limited effectiveness hinder their widespread use. Therefore, novel compounds with strong anti-inflammatory efficacy are still required. In this study, we investigated the anti-inflammatory effect and potential mechanisms of Gynostemma pentaphyllum (Thunb.) Makino saponins (GpS), a major component of the herbal medicine widely used in Asian countries. In in vitro studies, we demonstrated that GpS dose dependently suppressed activation of macrophages, one of the main effectors in IBD. GpS also suppressed cytokine production and the activation of NF-κB and STAT3 signaling in lipopolysaccharide-induced macrophages, without affecting their viability. Further in vivo studies demonstrated that GpS could ameliorate the weight loss, increased disease activity index, colon shortening and histological damage associated with dextran sulfate sodium (DSS)-induced colitis in mice. In agreement with results from our in vitro experiments, GpS suppressed cytokine production and activation of NF-κB and STAT3 signaling in the colons of DSS-induced mice. In this study, we present for the first time, evidence of the therapeutic effect of GpS in IBD, highlighting its potential as an effective therapeutic against the disease.

Therapeutic targeting of CBP/ß-catenin signaling reduces cancer stem-like population and synergistically suppresses growth of EBV-positive nasopharyngeal carcinoma cells with cisplatin.

Nasopharyngeal carcinoma (NPC) is an EBV-associated epithelial malignancy prevalent in southern China. Presence of treatment-resistant cancer stem cells (CSC) may associate with tumor relapse and metastasis in NPC. ICG-001 is a specific CBP/ß-catenin antagonist that can block CBP/ß-catenin-mediated transcription of stem cell associated genes and enhance p300/ß-catenin-mediated transcription, thereby reducing the CSC-like population via forced differentiation. In this study, we aimed to evaluate the effect of ICG-001 on the CSC-like population, and the combination effect of ICG-001 with cisplatin in the C666-1 EBV-positive NPC cells. Results showed that ICG-001 inhibited C666-1 cell growth and reduced expression of CSC-associated proteins with altered expression of epithelial-mesenchymal transition (EMT) markers. ICG-001 also inhibited C666-1 tumor sphere formation, accompanied with reduced SOX2(hi)/CD44(hi) CSC-like population. ICG-001 was also found to restore the expression of a tumor suppressive microRNA-145 (miR-145). Ectopic expression of miR-145 effectively repressed SOX2 protein expression and inhibited tumor sphere formation. Combination of ICG-001 with cisplatin synergistically suppressed in vitro growth of C666-1 cells and significantly suppressed growth of NPC xenografts. These results suggested that therapeutically targeting of the CBP/ß-catenin signaling pathway with ICG-001 can effectively reduce the CSC-like population and combination with cisplatin can effectively suppress the growth of NPC.