TMEM65 promotes gastric tumorigenesis by targeting YWHAZ to activate PI3K-Akt-mTOR pathway and is a therapeutic target.

Copy number alterations are crucial for the development of gastric cancer (GC). Here, we identified Transmembrane Protein 65 (TMEM65) amplification by genomic hybridization microarray to profile copy-number variations in GC. TMEM65 mRNA level was significantly up-regulated in GC compared to adjacent normal tissues, and was positively associated with TMEM65 amplification. High TMEM65 expression or DNA copy number predicts poor prognosis (P < 0.05) in GC. Furtherly, GC patients with TMEM65 amplification (n = 129) or overexpression (n = 78) significantly associated with shortened survival. Ectopic expression of TMEM65 significantly promoted cell proliferation, cell cycle progression and cell migration/invasion ability, but inhibited apoptosis (all P < 0.05). Conversely, silencing of TMEM65 in GC cells showed opposite abilities on cell function in vitro and suppressed tumor growth and lung metastasis in vivo (all P < 0.01). Moreover, TMEM65 depletion by VNP-encapsulated TMEM65-siRNA significantly suppressed tumor growth in subcutaneous xenograft model. Mechanistically, TMEM65 exerted oncogenic effects through activating PI3K-Akt-mTOR signaling pathway, as evidenced of increased expression of key regulators (p-Akt, p-GSK-3ß, p-mTOR) by Western blot. YWHAZ (Tyrosine 3-Monooxygenase/Tryptophan 5-Monooxygenase) was identified as a direct downstream effector of TMEM65. Direct binding of TMEM65 with YWHAZ in the cytoplasm inhibited ubiquitin-mediated degradation of YWHAZ. Moreover, oncogenic effect of TMEM65 was partly dependent on YWHAZ. In conclusion, TMEM65 promotes gastric tumorigenesis by activating PI3K-Akt-mTOR signaling via cooperating with YWHAZ. TMEM65 overexpression may serve as an independent new biomarker and is a therapeutic target in GC.

TRIP6 disrupts tight junctions to promote metastasis and drug resistance and is a therapeutic target in colorectal cancer.

Metastasis is the primary cause of death in colorectal cancer (CRC). Thyroid hormone receptor interacting protein 6 (TRIP6) is an adaptor protein that regulates cell motility. Here, we aim to elucidate the role of TRIP6 in driving CRC tumorigenesis and metastasis and evaluate its potential as a therapeutic target. TRIP6 mRNA is up-regulated in CRC compared to adjacent normal tissues in three independent cohorts (all P < 0.0001), especially in liver metastases (P < 0.001). High TRIP6 expression predicts poor prognosis of CRC patients in our cohort (P = 0.01) and TCGA cohort (P = 0.02). Colon-specific TRIP6 overexpression (Trip6KIVillin-Cre) in mice accelerated azoxymethane (AOM)-induced CRC (P < 0.05) and submucosal invasion (P < 0.0001). In contrast, TRIP6 knockout (Trip6+/- mice) slowed tumorigenesis (P < 0.05). Consistently, TRIP6 overexpression in CRC cells promoted epithelial-mesenchymal transition (EMT), cell migration/invasion in vitro, and metastases in vivo (all P < 0.05), whereas knockdown of TRIP6 exerted opposite phenotypes. Mechanistically, TRIP6 interacted PDZ domain-containing proteins such as PARD3 to impair tight junctions, evidenced by decreased tight junction markers and gut permeability dysfunction, inhibit PTEN, and activate oncogenic Akt signaling. TRIP6-induced pro-metastatic phenotypes and Akt activation depends on PARD3. Targeting TRIP6 by VNP-encapsulated TRIP6-siRNA synergized with Oxaliplatin and 5-Fluorouracil to suppress CRC liver metastases. In conclusion, TRIP6 promotes CRC metastasis by directly interacting with PARD3 to disrupt tight junctions and activating Akt signaling. Targeting of TRIP6 in combination with chemotherapy is a promising strategy for the treatment of metastatic CRC.

Traditional Medicine Pien Tze Huang Suppresses Colorectal Tumorigenesis Through Restoring Gut Microbiota and Metabolites.

BACKGROUND & AIMS: Pien Tze Huang (PZH) is a well-established traditional medicine with beneficial effects against inflammation and cancer. We aimed to explore the chemopreventive effect of PZH in colorectal cancer (CRC) through modulating gut microbiota. METHODS: CRC mouse models were established by azoxymethane plus dextran sulfate sodium treatment or in Apcmin/+ mice treated with or without PZH (270 mg/kg and 540 mg/kg). Gut barrier function was determined by means of intestinal permeability assays and transmission electron microscopy. Fecal microbiota and metabolites were analyzed by means of metagenomic sequencing and liquid chromatography mass spectrometry, respectively. Germ-free mice or antibiotic-treated mice were used as models of microbiota depletion. RESULTS: PZH inhibited colorectal tumorigenesis in azoxymethane plus dextran sulfate sodium-treated mice and in Apcmin/+ mice in a dose-dependent manner. PZH treatment altered the gut microbiota profile, with an increased abundance of probiotics Pseudobutyrivibrio xylanivorans and Eubacterium limosum, while pathogenic bacteria Aeromonas veronii, Campylobacter jejuni, Collinsella aerofaciens, and Peptoniphilus harei were depleted. In addition, PZH increased beneficial metabolites taurine and hypotaurine, bile acids, and unsaturated fatty acids, and significantly restored gut barrier function. Transcriptomic profiling revealed that PZH inhibited PI3K-Akt, interleukin-17, tumor necrosis factor, and cytokine-chemokine signaling. Notably, the chemopreventive effect of PZH involved both microbiota-dependent and -independent mechanisms. Fecal microbiota transplantation from PZH-treated mice to germ-free mice partly recapitulated the chemopreventive effects of PZH. PZH components ginsenoside-F2 and ginsenoside-Re demonstrated inhibitory effects on CRC cells and primary organoids, and PZH also inhibited tumorigenesis in azoxymethane plus dextran sulfate sodium-treated germ-free mice. CONCLUSIONS: PZH manipulated gut microbiota and metabolites toward a more favorable profile, improved gut barrier function, and suppressed oncogenic and pro-inflammatory pathways, thereby suppressing colorectal carcinogenesis.

TUBB4B is a novel therapeutic target in non-alcoholic fatty liver disease-associated hepatocellular carcinoma.

Non-alcoholic fatty liver disease-associated hepatocellular carcinoma (NAFLD-HCC) is an emerging malignancy due to the rising prevalence of NAFLD. However, no drug is available to target NAFLD-HCC. In this study, we aim to unravel novel therapeutic targets of NAFLD-HCC utilizing a high-throughput CRISPR/Cas9 screening strategy. We utilized the Epi-drug CRISPR/Cas9 library consisting of single-guide RNAs (sgRNAs) targeting over 1,000 genes representing the FDA-approved drug targets and epigenetic regulators to perform loss-of-function screening in two NAFLD-HCC cell lines (HKCI2 and HKCI10). CRISPR/Cas9 library screening unraveled TUBB4B as an essential gene for NAFLD-HCC cell growth. TUBB4B was overexpressed in NAFLD-HCC tumors compared with adjacent normal tissues (N = 17) and was associated with poor survival (p < 0.01). RNA-sequencing and functional assays revealed that TUBB4B knockout in NAFLD-HCC promoted cell apoptosis, cell cycle arrest, and cellular senescence, leading to suppressed NAFLD-HCC growth in vitro and in vivo. We identified that TUBB4B inhibitor mebendazole (MBZ), an FDA-approved drug, inhibited NAFLD-HCC growth by inducing apoptosis and cellular senescence. Since protein expression of pro-survival Bcl-xL was induced in TUBB4B knockout NAFLD-HCC cells, we examined combination of TUBB4B inhibition with navitoclax, a Bcl-xL inhibitor that selectively targets senescent cells. Consistent with our hypothesis, either TUBB4B knockout or MBZ synergized with navitoclax to inhibit NAFLD-HCC cell growth via the induction of intrinsic and extrinsic apoptosis pathways. In summary, TUBB4B is a novel therapeutic target in NAFLD-HCC. Inhibition of TUBB4B with MBZ in combination with navitoclax synergistically inhibited NAFLD-HCC cell growth, representing a promising strategy for the treatment of NAFLD-HCC. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.