Loss of ASXL1 expression is associated with lymph node metastasis in colorectal cancer

CBX1 is involved in hepatocellular carcinoma progression and resistance to sorafenib and lenvatinib via IGF-1R/AKT/SNAIL signaling pathway

BACKGROUND

Chromobox Homolog 1 (CBX1) plays a crucial role in the pathogenesis of numerous diseases, including the evolution and advancement of diverse cancers. The role of CBX1 in pan-cancer and its mechanism in hepatocellular carcinoma (HCC), however, remains to be further investigated.

METHODS

Bioinformatics approaches were harnessed to scrutinize CBX1's expression profile, its association with tumor staging, and its potential impact on patient outcomes across various cancers. Single-cell RNA sequencing data facilitated the investigation of CBX1 expression patterns at the individual cell level. The CBX1 expression levels in HCC and adjacent non-tumor tissues were quantified through Real-Time Polymerase Chain Reaction (RT-PCR), Western Blotting (WB), and Immunohistochemical analyses. A tissue microarray was employed to explore the relationship between CBX1 levels, patient prognosis, and clinicopathological characteristics in HCC. Various in vitro assays-including CCK-8, colony formation, Transwell invasion, and scratch tests-were conducted to assess the proliferative and motility properties of HCC cells upon modulation of CBX1 expression. Moreover, the functional impact of CBX1 on HCC was further discerned through xenograft studies in nude mice.

RESULTS

CBX1 was found to be upregulated in most cancer forms, with heightened expression correlating with adverse patient prognoses. Within the context of HCC, elevated levels of CBX1 were consistently indicative of poorer clinical outcomes. Suppression of CBX1 through knockdown methodologies markedly diminished HCC cell proliferation, invasive capabilities, migratory activity, Epithelial-mesenchymal transition (EMT) processes, and resistance to Tyrosine kinase inhibitors (TKIs). Contrastingly, CBX1 augmentation facilitated the opposite effects. Subsequent investigative efforts revealed CBX1 to be a promoter of EMT and a contributor to increased TKI resistance within HCC cells, mediated via the IGF-1R/AKT/SNAIL signaling axis. The oncogenic activities of CBX1 proved to be attenuable either by AKT pathway inhibition or by targeted silencing of IGF-1R.

CONCLUSIONS

The broad overexpression of CBX1 in pan-cancer and specifically in HCC positions it as a putative oncogenic entity. It is implicated in forwarding HCC progression and exacerbating TKI resistance through its interaction with the IGF-1R/AKT/SNAIL signaling cascade.

Additional Sex Combs-like Family Associated with Epigenetic Regulation

The additional sex combs-like (ASXL) family, a mammalian homolog of the additional sex combs (Asx) of Drosophila, has been implicated in transcriptional regulation via chromatin modifications. Abnormal expression of ASXL family genes leads to myelodysplastic syndromes and various types of leukemia. De novo mutation of these genes also causes developmental disorders. Genes in this family and their neighbor genes are evolutionary conserved in humans and mice. This review provides a comprehensive summary of epigenetic regulations associated with ASXL family genes. Their expression is commonly regulated by DNA methylation at CpG islands preceding transcription starting sites. Their proteins primarily engage in histone tail modifications through interactions with chromatin regulators (PRC2, TrxG, PR-DUB, SRC1, HP1α, and BET proteins) and with transcription factors, including nuclear hormone receptors (RAR, PPAR, ER, and LXR). Histone modifications associated with these factors include histone H3K9 acetylation and methylation, H3K4 methylation, H3K27 methylation, and H2AK119 deubiquitination. Recently, non-coding RNAs have been identified following mutations in the ASXL1 or ASXL3 gene, along with circular ASXLs and microRNAs that regulate ASXL1 expression. The diverse epigenetic regulations linked to ASXL family genes collectively contribute to tumor suppression and developmental processes. Our understanding of ASXL-regulated epigenetics may provide insights into the development of therapeutic epigenetic drugs.

Pretreatment with an antibiotics cocktail enhances the protective effect of probiotics by regulating SCFA metabolism and Th1/Th2/Th17 cell immune responses

BACKGROUND

Probiotics are a potentially effective therapy for inflammatory bowel disease (IBD); IBD is linked to impaired gut microbiota and intestinal immunity. However, the utilization of an antibiotic cocktail (Abx) prior to the probiotic intervention remains controversial. This study aims to identify the effect of Abx pretreatment from dextran sulfate sodium (DSS)-induced colitis and to evaluate whether Abx pretreatment has an enhanced effect on the protection of Clostridium butyricum Miyairi588 (CBM) from colitis.

RESULTS

The inflammation, dysbiosis, and dysfunction of gut microbiota as well as T cell response were both enhanced by Abx pretreatment. Additionally, CBM significantly alleviated the DSS-induced colitis and impaired gut epithelial barrier, and Abx pretreatment could enhance these protective effects. Furthermore, CBM increased the benefit bacteria abundance and short-chain fatty acids (SCFAs) level with Abx pretreatment. CBM intervention after Abx pretreatment regulated the imbalance of cytokines and transcription factors, which corresponded to lower infiltration of Th1 and Th17 cells, and increased Th2 cells.

CONCLUSIONS

Abx pretreatment reinforced the function of CBM in ameliorating inflammation and barrier damage by increasing beneficial taxa, eliminating pathogens, and inducing a protective Th2 cell response. This study reveals a link between Abx pretreatment, microbiota, and immune response changes in colitis, which provides a reference for the further application of Abx pretreatment before microbiota-based intervention.

The role of ASXL1 mutations and ASXL1 CircRNAs in cancer

BACKGROUND

Mutations in the Additional Sex Combs Like 1 (ASXL1) gene were first reported in myelodysplastic syndromes. Recent studies have clarified the relationship between ASXL1 mutations and the development of cancers.

OBJECTIVE

This study aims to review the roles of ASXL1 and ASXL1 CircRNAs, such as epigenetic regulation, chromatin modification, and transcription factor function in malignancies.

METHOD

This study is a review of articles related to the role of ASXL1 and ASXL1 CircRNAs in malignancies, retrieved from PubMed and Scopus.

RESULTS

ASXL1 plays a role in malignancies and is also related to poor overall survival and cancer metastasis. ASXL1 encodes conserved and abundant Circular RNAs (circRNAs) that act as post-transcriptional regulators, regulating tumorigenesis and progression in cancer. ASXL1 circRNA was identified in the top 10% of differentially expressed circRNAs in clinically relevant tissues. Additionally, the role of ASXL1 gene circRNAs in cancer development is reviewed in this study.

CONCLUSION

ASXL1 and ASXL1circRNA have dual functions in combination with different proteins, being involved in both transcriptional activation and repression in a context-dependent manner. Moreover, studies indicate these genes play an important role in epithelial-mesenchymal transition (EMT) and metastasis. Ongoing research is aimed at determining this gene family's function in biological events.

Forkhead Box q1 promotes invasion and metastasis in colorectal cancer by activating the epidermal growth factor receptor pathway

BACKGROUND

Colorectal cancer (CRC) is an extremely malignant tumor with a high mortality rate. Little is known about the mechanism by which forkhead Box q1 (FOXQ1) causes CRC invasion and metastasis through the epidermal growth factor receptor (EGFR) pathway.

AIM

To illuminate the mechanism by which FOXQ1 promotes the invasion and metastasis of CRC by activating the heparin binding epidermal growth factor (HB-EGF)/EGFR pathway.

METHODS

We investigated the differential expression and prognosis of FOXQ1 and HB-EGF in CRC using the Gene Expression Profiling Interactive Analysis (GEPIA) website (http://gepia.cancer-pku.cn/index.html). Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to detect the expression of FOXQ1 and HB-EGF in cell lines and tissues, and we constructed a stable low-expressing FOXQ1 cell line and verified it with the above method. The expression changes of membrane-bound HB-EGF (proHB-EGF) and soluble HB-EGF (sHB-EGF) in the low-expressing FOXQ1 cell line were detected by flow cytometry and ELISA. Western blotting was used to detect changes in the expression levels of HB-EGF and EGFR pathway-related downstream genes when exogenous recombinant human HB-EGF was added to FOXQ1 knockdown cells. Proliferation experiments, transwell migration experiments, and scratch experiments were carried out to determine the mechanism by which FOXQ1 activates the EGFR signaling pathway through HB-EGF, and then to evaluate the clinical relevance of FOXQ1 and HB-EGF.

RESULTS

GEPIA showed that the expression of FOXQ1 in CRC tissues was relatively high and was related to a lower overall survival rate. PCR array results showed that FOXQ1 is related to the HB-EGF and EGFR pathways. Knockdown of FOXQ1 suppressed the expression of HB-EGF, and led to a decrease in EGFR and its downstream genes AKT, RAF, KRAS expression levels. After knockdown of FOXQ1 in CRC cell lines, cell proliferation, migration and invasion were attenuated. Adding HB-EGF restored the migration and invasion ability of CRC, but not the cell proliferation ability. Kaplan–Meier survival analysis results showed that the combination of FOXQ1 and HB-EGF may serve to predict CRC survival.

CONCLUSION

Based on these collective data, we propose that FOXQ1 promotes the invasion and metastasis of CRC via the HB-EGF/EGFR pathway.

LINC00586 Represses ASXL1 Expression Thus Inducing Epithelial-To-Mesenchymal Transition of Colorectal Cancer Cells Through LSD1-Mediated H3K4me2 Demethylation

Colorectal cancer (CRC) is a major public health problem on a global scale by virtue of its relatively high incidence. The transition of tumor cells from an epithelial to a mesenchymal-like phenotype, so-called epithelial-to-mesenchymal transition (EMT), is a key hallmark of human cancer metastasis, including CRC. Understanding the signaling events that initiate this phenotypic switch may provide opportunities to limit the metastasis of CRC. In this study, we aim to identify long non-coding RNA (lncRNA) mediated epigenetic regulation under the context of CRC. 54 paired samples of tumor tissues and surrounding non-tumor tissues were collected from CRC patients. Cultured human CRC cells HCT116 and LoVo were assayed for their viability and migration using CCK-8 tests and transwell migration assays. The expression of EMT-specific markers (E-cadherin, N-cadherin and vimentin) was analyzed biochemically by RT-qPCR and immunoblot analyses. Interaction among LINC00586, LSD1, and ASXL1 was determined by RNA immunoprecipitation and chromatin immunoprecipitation. In vivo analysis of LINC00586 was performed in nude mice xenografted with HCT116 cells. LINC00586 was overexpressed in CRC tissues and associated with patient survival. LINC00586 knockdown repressed HCT116 and LoVo cell viability, migration, their phenotypic switch from epithelial to a mesenchymal, and tumorigenesis in vivo. We demonstrated LINC00586 recruited the LSD1 into the ASXL1 promoter region and epigenetically silenced the ASXL1 expression. An ASXL1 gene resisting to LINC00586 attack was demonstrated in cultured HCT116 and LoVo cells and mouse xenograft models of human CRC. Overall, discovery of the LINC00586/LSD1/ASXL1 axis partially explains epigenetic mechanism regulating EMT in CRC, providing a therapeutic target to limit CRC metastasis.

ASXL1 promotes adrenocortical carcinoma and is associated with chemoresistance to EDP regimen

Adrenocortical carcinoma (ACC) is a rare but aggressive disease that lacks definitive treatment. We aim to evaluate role of ASXL1 in ACC and exploit its therapeutic merits therein. We performed in silico reproduction of datasets of the Cancer Genome Atlas (TCGA), GDSC (Genomics of Drug Sensitivity in Cancer) and Human Protein Atlas using platforms of cBioPortal, UALCAN, NET-GE, GSEA and GEPIA. Validation in ACC was performed in tissue, in vitro and in vivo using the NCI-H295R and SW-13 cells. ASXL1 was gained in over 50% of ACC cases with its mRNA overexpressed in DNA gained cases. ASXL1 overexpression was associated with recurrence and worsened prognosis in ACC. ASXL1 gain was associated with resistance to etoposide, doxorubicin and cisplatin (EDP). ASXL1 expression was positively correlated with FSCN1 expression. Targeting ASXL1 significantly impaired fitness of ACC cells, which could be in part rescued by FSCN1 overexpression. Targeting FSCN1 however could not rescue resistance to EDP induced by ASXL1 overexpression. Targeting ASXL1 sensitized ACC cells to EDP regimen but constitutive ASXL3 overexpression in SW-13 cells could induce resistance upon prolonged treatment. Functional gain of ASXL1 was common in ACC and exerted pro-tumorigenic and chemoresistance role. Targeting ASXL1 hold promise to ACC treatment.