Targeting AKT induced Ferroptosis through FTO/YTHDF2-dependent GPX4 m6A methylation up-regulating and degradating in colorectal cancer.

Ferroptosis is a new type of iron-dependent programmed cell death induced by lipid peroxidation. However, the underlying mechanisms and function in tumor therapy still remain undisclosed especially in post-transcription regulation. Here, we found that targeting AKT significantly induced GPX4 dependent ferroptosis and suppressed colorectal cancer growth both in vitro and in vivo. During this process, demethylase FTO was downregulated, which increased the m6A methylation level of GPX4, subsequently recognized by YTHDF2 and degraded. Prediction results showed that there are three potential methylated sites (193/647/766), and 193 site was identified as the right one, which was demethylated by FTO and read by YTHDF2. In parallel, AKT inhibition caused the accumulation of ROS which had a negative feedback on GPX4 expression. In addition, protective autophagy was initiated by MK2206 stimulation, while blocking autophagy further increased ferroptosis and markedly enhanced the anti-tumor activity of MK2206. In a word, inhibiting AKT activated ferroptosis through FTO/YTHDF2/GPX4 axis to suppress colon cancer progression, which raised FTO/GPX4 as potential biomarkers and targets in colorectal cancer therapy.

Protocol for inducing branching morphogenesis in human cholangiocyte and cholangiocarcinoma organoids.

Bile ducts are essential for bile transport and consist of complex branching tubular networks. Human patient-derived cholangiocyte develops a cystic rather than branching duct morphology. Here, we present a protocol to establish branching morphogenesis in cholangiocyte and cholangiocarcinoma organoids. We describe steps for the initiation, maintenance, and expansion of intrahepatic cholangiocyte organoids branching morphology. This protocol enables the study of organ-specific and mesenchymal-independent branching morphogenesis and provides an improved model to study biliary function and diseases. For complete details on the use and execution of this protocol, please refer to Roos et al. (2022).1.

Mutant p53 achieved Gain-of-Function by promoting tumor growth and immune escape through PHLPP2/AKT/PD-L1 pathway.

The most frequent genetic alterations of the TP53 gene in human cancer were reported. TP53 mutation gains new function as a target of genetic instability, which is associated with increased tumor progression and poor survival rate in patients. In this study, more than three hundred colorectal cancer patients' samples were firstly analyzed, and the results showed that patients with mutant p53 had higher levels of AKT phosphorylation and PD-L1 expression, which were next verified both in cell lines in vitro and patients' samples in vivo. Further studies demonstrated that the hotspot of mutant p53 directly binds to the promoter of PHLPP2 to inhibit its transcription, and resulting in down-regulating its protein expressional level. Subsequently, AKT was released and activated, promoting tumor proliferation and metastasis. In parallel, 4EBP1/eIF4E was identified as downstream executors of AKT to enhance the translational level of PD-L1, which decreased the activation of T cells. Besides, inhibiting AKT/mTOR pathway significantly suppressed PD-L1 expression, tumor growth, and immune escape in p53 mutated cells. In conclusion, mutant p53 achieved its Gain-of-Function by transcriptionally inhibiting PHLPP2 and activating AKT, which suppresses immune response and advances tumor growth. Thus, this study provides an excellent basis for a further understanding of the clinical treatment of neoplastic diseases for patients with mutant p53, with an emphasis on immunotherapy.

Targeting ERK induced cell death and p53/ROS-dependent protective autophagy in colorectal cancer.

In recent years, many studies have shown that autophagy plays a vital role in the resistance of tumor chemotherapy. However, the interaction between autophagy and cell death has not yet been clarified. In this study, a new specific ERK inhibitor CC90003 was found to suppress colorectal cancer growth by inducing cell death both in vitro and in vivo. Studies have confirmed that higher concentrations of ROS leads to autophagy or cell death. In this research, the role of CC90003-induced ROS was verified. But after inhibiting ROS by two kinds of ROS inhibitors NAC and SFN, the autophagy induced by CC90003 decreased, while cell death strengthened. In parallel, protective autophagy was also induced, while in a p53-dependent manner. After silencing p53 or using the p53 inhibitor PFTα, the autophagy induced by CC90003 was weakened and the rate of cell death increases. Therefore, we confirmed that CC90003 could induce autophagy by activating ROS/p53. Furthermore, in the xenograft mouse model, the effect was obtained remarkably in the combinational treatment group of CC90003 plus CQ, comparing with that of the single treatment groups. In a word, our results demonstrated that targeting ERK leads to cell death and p53/ROS-dependent protective autophagy simultaneously in colorectal cancer, which offers new potential targets for clinical therapy.

Downregulation of miR-575 Inhibits the Tumorigenesis of Gallbladder Cancer via Targeting p27 Kip1.

BACKGROUND: Gallbladder cancer (GBC) is the most common biliary tract malignant cancer worldwide. It has been reported that microRNA-575 (miR-575) was involved in the tumorigenesis of many cancers. However, the role of miR-575 during the progression of GBC remains largely unknown. METHODS: The expression of miR-575 in GBC cells was detected by quantitative real-time polymerase chain reaction. The proliferation of GBC cells was examined by CCK-8 assay and Ki-67 staining. Apoptosis of GBC cells was measured by flow cytometry, and cell invasion was tested by transwell assay. Moreover, protein expressions in GBC cells were evaluated using Western blot. The target gene of miR-575 was predicted using Targetscan and miRDB. Finally, xenograft tumor model was established to verify the function of miR-575 in GBC in vivo. RESULTS: Our findings indicated that miR-575 antagonist decreased the proliferation and invasion of GBC cells. In addition, miR-575 antagonist significantly induced apoptosis of GBC cells via inducing G1 arrest. Meanwhile, p27 Kip1 was found to be a direct target of miR-575 with luciferase reporter assay. Moreover, miR-575 antagonist significantly decreased the expressions of CDK1 and cyclin E1 and upregulated the levels of cleaved caspase3 and p27 Kip1 in GBC cells. Finally, miR-575 antagonist notably suppressed GBC tumor growth in vivo. CONCLUSION: Downregulation of miR-575 significantly inhibited the tumorigenesis of GBC via targeting p27 Kip1. Thus, miR-575 might be a potential novel target for the treatment of GBC.

Competing endogenous RNA network analysis reveals potential long non-coding RNAs as predictive biomarkers of gastric cancer.

Gastric cancer (GC) is one of the most frequently occurring life-threatening malignancies worldwide. Due to its high mortality rate, the discovery of putative biomarkers that may be sensitive and specific to GC is of seminal importance. Long non-coding RNAs (lncRNAs) are non-translatable RNAs whose transcript length exceeds 200 base pairs. The dysregulation of lncRNA expression plays a key role in tumorigenesis and development. In the present study, the expression profiles of lncRNAs, microRNAs and mRNAs of 361 GC tissues (and 32 normal gastric tissues) were downloaded from The Cancer Genome Atlas database. Furthermore, differentially expressed RNAs were analyzed by the DEseq package. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses confirmed some significant dysregulated signaling pathways and target RNAs. As a result, an lncRNA-associated competing endogenous RNA (ceRNA) network was constructed. Kaplan-Meier analysis of the differentially expressed RNAs associated with GC pathogenesis confirmed that the lncRNAs PVT1, HAND2-AS1 and ZNF667-AS1 were potentially associated with the prognosis of GC (P<0.05). The present study suggests the mechanism of ceRNA networks in GC, and further demonstrates that aberrant lncRNA expression may be used as an effective diagnostic tool (or target) for the prognosis of GC.

SNP rs12982687 affects binding capacity of lncRNA UCA1 with miR-873-5p: involvement in smoking-triggered colorectal cancer progression.

BACKGROUND: This investigation was arranged to elucidate whether single nucleotide polymorphisms (SNPs) of lncRNA UCA1 was implicated in elevating colorectal cancer (CRC) risk by interacting with environmental exposures. METHODS: LncRNASNP database was firstly adopted to predict SNPs that possibly affected binding of UCA1 with miRNAs and then the interactive effect of SNPs and environmental exposure on CRC risk was evaluated by recurring to type 2 gene-environment interactions (GEI) model. Besides, MTT assay, colony formation assay, transwell assay and wound healing assay were performed to assess the activity of CRC cell lines which carried distinct genotypes of specific SNPs. The impact of nicotine on activity of CRC cells was also appraised. RESULTS: SNP rs12982687 of UCA1 intervened in the binding capacity of UCA1 with several miRNAs, especially miR-873-5p. MiRNAs regulated by UCA1, as predicted by mirPath software, shared genes that were enriched in HIF1 signaling pathway. Moreover, homozygote TT of rs12982687 reduced CRC risk among smokers, and CRC cells that carried rs12982687 (CC) displayed strong migration and invasion. By contrast, miR-873-5p mimic, which reduced UCA1 expression, delayed metastasis of CRC cells (all P < 0.05). Additionally, nicotine not merely elevated UCA1 and HIF-1α expressions in CRC cells, but also facilitated proliferation and metastasis of CRC cells (P < 0.05). CONCLUSIONS: SNP rs12982687 was involved in smoking-triggered CRC progression, given its influence on UCA1's binding with miR-873-5p and HIF-1 signaling.