MiR-199a-5p-Regulated SMARCA4 Promotes Oral Squamous Cell Carcinoma Tumorigenesis

Chromatin remodeling and cancer: the critical influence of the SWI/SNF complex

The SWI/SNF complex was first identified in yeast and named after studies of mutants critical for the mating-type switch (SWI) and sucrose non-fermenting (SNF) pathways.The SWI/SNF complex plays a pivotal role in regulating gene expression by altering chromatin structure to promote or suppress the expression of specific genes, maintain stem cell pluripotency, and participate in various biological processes. Mutations in the SWI/SNF complex are highly prevalent in various human cancers, significantly impacting tumor suppressive or oncogenic functions and influencing tumor initiation and progression. This review focuses on the mechanisms by which ARID1A/ARID1B, PBRM1, SMARCB1, and SMARCA2/SMARCA4 contribute to cancer, the immunoregulatory roles of the SWI/SNF complex, its involvement in DNA repair pathways, synthetic lethality, and applications in precision oncology.

Loss of SMARCA4 induces sarcomatogenesis through epithelial-mesenchymal transition in ovarian carcinosarcoma

Ovarian carcinosarcoma (OCS) is a rare and aggressive tumor, and the development of its sarcomatous component is believed to be due to epithelial-mesenchymal transition (EMT). The SWIch/sucrose nonfermentable chromatin remodeling factor (CRF) is closely related to EMT; however, the relationship between CRF and EMT in OCS remains unclear. In this study, we analyzed the protein expression of CRFs, including ARID1A and SMARCA4, and their downstream mRNA expression in 28 OCS cases, two fallopian tube CS cases, and one peritoneal CS case. ARID1A and SMARCA4 exhibited a histological type-specific loss of protein expression in 5 of 11 (45%) endometrioid cases and all 5 serous/homologous OCS cases, respectively. The mRNA analysis suggested that sarcomatogenesis is induced by the transforming growth factor-β and Hippo signaling pathways, both of which regulate YAP1. Immunostaining for YAP1 suggested YAP1-associated sarcomatogenesis in the CRF-retained group, whereas YAP1-unassociated sarcomatogenesis was suggested in the CRF-reduced group. High-grade serous carcinoma cell line experiments showed that the transcriptome of the SMARCA4-knockdown group showed lower expression of the epithelial gene CDH1 and higher expression of mesenchymal genes such as VIM, ZEB1, and SNAI1 than the control group. Moreover, cell adhesion disappeared and cell morphology changed to a spindle shape, indicating sarcomatogenesis. In conclusion, this study reveals a mechanism for sarcoma development in OCS and provides novel therapeutic possibilities.

SRF and CBP jointly regulate integrin β6 overexpression in head and neck squamous cell carcinomas

Overexpression of integrin β6 (ITGB6) is crucially linked to the invasion and metastasis of head and neck squamous cell carcinoma (HNSCC). The molecular mechanisms driving ITGB6 upregulation in HNSCC are not well understood. Our study comprehensively analyzed the transcriptional regulation and epigenetic modification mechanisms affecting ITGB6 transcription. We retrospectively evaluated ITGB6 expression using immunohistochemistry on a tissue microarray. Elevated ITGB6 expression in HNSCC specimens correlates with poor clinical prognosis. Using a luciferase reporter assay, site-directed mutagenesis, RNA interference, chromatin immunoprecipitation assay, and a 4-nitroquinoline 1-oxide (4NQO)-induced murine HNSCC model, we have demonstrated that the transcription factor Serum Response Factor (SRF) upregulates ITGB6 transcription. Our results further demonstrated that the histone acetyltransferase (HAT) CBP mediates the hyperacetylation of histones H3 and H4, facilitating their recruitment to the ITGB6 promoter. This recruitment strengthens SRF binding to the ITGB6 promoter. These findings suggest that SRF and CBP-mediated histone hyperacetylation are crucial for ITGB6 overexpression in HNSCC. Epigenetic mechanisms play a critical role in the active transcriptional expression of ITGB6 in HNSCC cells.

Metastasis and cell proliferation inhibition by microRNAs and its potential therapeutic applications in OSCC: A systematic review

BACKGROUND AND AIMS

Oral squamous cell carcinoma (OSCC) is among the most malignant cancers in the world and has a high mortality rate. MicroRNAs (miRNAs) have progressively gained attention due to their roles in the pathogenesis and maintenance of various kinds of cancers, including OSCC. In this research, we carried out a scoping review to analyze the role of miRNA and therapeutic response in OSCC and focus on target axes associated with miRNA that inhibit metastasis and cell proliferation in OSCC.

METHODS

This review adhered to a six-stage methodology framework and PRISMA guidelines. Three databases were systematically searched to find eligible articles until July 2024. Two reviewers conducted publication screening and data extraction independently. 54 articles meeting the predefined inclusion criteria were successfully identified. Quality assessment was done using the QUIN checklist specified for dental in vitro studies.

RESULTS

Studies with different designs reported 53 miRNAs that were experimentally validated to act as therapeutic targets in OSCC in vivo and in vitro studies. The study found that 25 miRNAs were up-regulated in OSCC patients and cell lines, while another 25 were down-regulated. Mir-186 was also found to be up- and down-regulated in two different investigations. The study highlights the potential of six microRNAs (miR-32-5p, miR-195-5p, miR-3529-3p, miR-191, miR-146b-5p, and miR-377-3p) as anti-proliferation, migration, and invasion therapeutics for OSCC treatment. Two miRNAs (miR-302b and miR-18a) are identified as anti-metastatic therapeutics, while four miRNAs (miR-617, miR-23a-3p, miR-105, miR-101) are anti-proliferation therapeutics.

CONCLUSION

The study recommends that restoring the expression of tumor suppressor miRNAs may be a suitable cancer therapy. Utilizing this technology does present certain difficulties, and resolving them will improve the methods for miRNA transfer to target cells. With more research and the resolution of associated issues, miRNA can be employed as an efficient therapeutic method for OSCC.

Pan-cancer dissection of vasculogenic mimicry characteristic to provide potential therapeutic targets

Introduction

Vasculogenic mimicry (VM) represents a novel form of tumor angiogenesis that is associated with tumor invasiveness and drug resistance. However, the VM landscape across cancer types remains poorly understood. In this study, we elucidate the characterizations of VM across cancers based on multi-omics data and provide potential targeted therapeutic strategies.

Methods

Multi-omics data from The Cancer Genome Atlas was used to conduct comprehensive analyses of the characteristics of VM related genes (VRGs) across cancer types. Pan-cancer vasculogenic mimicry score was established to provide a depiction of the VM landscape across cancer types. The correlation between VM and cancer phenotypes was conducted to explore potential regulatory mechanisms of VM. We further systematically examined the relationship between VM and both tumor immunity and tumor microenvironment (TME). In addition, cell communication analysis based on single-cell transcriptome data was used to investigate the interactions between VM cells and TME. Finally, transcriptional and drug response data from the Genomics of Drug Sensitivity in Cancer database were utilized to identify potential therapeutic targets and drugs. The impact of VM on immunotherapy was also further clarified.

Results

Our study revealed that VRGs were dysregulated in tumor and regulated by multiple mechanisms. Then, VM level was found to be heterogeneous among different tumors and correlated with tumor invasiveness, metastatic potential, malignancy, and prognosis. VM was found to be strongly associated with epithelial-mesenchymal transition (EMT). Further analyses revealed cancer-associated fibroblasts can promote EMT and VM formation. Furthermore, the immune-suppressive state is associated with a microenvironment characterized by high levels of VM. VM score can be used as an indicator to predict the effect of immunotherapy. Finally, seven potential drugs targeting VM were identified.

Conclusion

In conclusion, we elucidate the characteristics and key regulatory mechanisms of VM across various cancer types, underscoring the pivotal role of CAFs in VM. VM was further found to be associated with the immunosuppressive TME. We also provide clues for the research of drugs targeting VM. Our study provides an initial overview and reference point for future research on VM, opening up new avenues for therapeutic intervention.

BRG1 mediates epigenetic regulation of TNFα-induced CCL2 expression in oral tongue squamous cell carcinoma cells

Strong evidence has indicated that upregulation of chemokine (CC motif) ligand-2 (CCL2) expression and the presence of an inflammatory tumor microenvironment significantly contribute to the migratory and invasive properties of oral squamous cell carcinoma, specifically oral tongue squamous cell carcinoma (OTSCC). However, the precise epigenetic mechanism responsible for enhanced CCL2 expression in response to the inflammatory mediator tumor necrosis factor alpha (TNF-α) in OTSCC remains inadequately elucidated. We have demonstrated that the production of CCL2 can be induced by TNF-α, and this induction is mediated by the chromatin remodel protein BRG1. Through the use of a chromatin immunoprecipitation (ChIP) assay, we have found that BRG1 was involved in the recruitment of acetylated histones H3 and H4 at the CCL2 promoter, thereby activating TNF-α-induced CCL2 transcription. Furthermore, we have observed that recruitment of NF-κB p65 to the CCL2 promoter was increased following BRG1 overexpression and decreased after BRG1 knockdown in OTSCC cells. Our Re-ChIP assay has shown that BRG1 knockdown completely inhibits the recruitment of both acetylated histone H3 or H4 and NF-κB to the CCL2 promoter. In summary, the findings of our study demonstrate that BRG1 plays a significant role in mediating the production of CCL2 in OTSCC cells in response to TNF-α stimulation. This process involves the cooperative action of acetylated histone and NF-κB recruitment to the CCL2 promoter site. Our data suggest that BRG1 serves as a critical epigenetic mediator in the regulation of TNF-α-induced CCL2 transcription in OTSCC cells.

Special Issue "Molecular Advances in Cancer Genetics 3.0"

The third volume of this Special Issue focuses on new advances in cancer genetics studies and collates papers reporting on a variety of mechanisms of tumorigenesis, the need to explore them from multiple perspectives, and the difficulties in exploring them, as well as the challenge of integrating them into a unifying but still different model for each tumor type [...].

Epigenetic regulation of mRNA mediates the phenotypic plasticity of cancer cells during metastasis and therapeutic resistance (Review)

Plasticity, the ability of cancer cells to transition between differentiation states without genomic alterations, has been recognized as a major source of intratumoral heterogeneity. It has a crucial role in cancer metastasis and treatment resistance. Thus, targeting plasticity holds tremendous promise. However, the molecular mechanisms of plasticity in cancer cells remain poorly understood. Several studies found that mRNA, which acts as a bridge linking the genetic information of DNA and protein, has an important role in translating genotypes into phenotypes. The present review provided an overview of the regulation of cancer cell plasticity occurring via changes in the transcription and editing of mRNAs. The role of the transcriptional regulation of mRNA in cancer cell plasticity was discussed, including DNA‑binding transcriptional factors, DNA methylation, histone modifications and enhancers. Furthermore, the role of mRNA editing in cancer cell plasticity was debated, including mRNA splicing and mRNA modification. In addition, the role of non‑coding (nc)RNAs in cancer plasticity was expounded, including microRNAs, long intergenic ncRNAs and circular RNAs. Finally, different strategies for targeting cancer cell plasticity to overcome metastasis and therapeutic resistance in cancer were discussed.

Knockdown of ABHD11‑AS1 prevents the procession of TNBC by upregulating miR‑199a‑5p

Breast cancer (BC) has become a threat to women's health. In addition, patients with triple-negative BC (TNBC) have the worst prognosis among all patients with BC. Furthermore, long non-coding RNA ABHD11-AS1 is aberrantly highly expressed in TNBC, suggesting that RNA ABHD11-AS1 may serve as an important role in the progression of TNBC. However, the detailed function of ABHD11-AS1 in TNBC remains largely unknown. The levels of ABHD11-AS1 in MDA-MB-231 cells were assessed by reverse transcription-quantitative PCR. To investigate the effect of ABHD11-AS1 on the progression of TNBC, a xenograft animal model was established. Knockdown of ABHD11-AS1 inhibited the epithelial-mesenchymal transition and migration of TNBC cells. In addition, ABHD11-AS1 promoted the viability and migration of TNBC cells by upregulating microRNA (miR)-199a-5p. Furthermore, knockdown of ABHD11-AS1 suppressed TNBC tumor growth in vivo by upregulating miR-199a-5p. In conclusion, knockdown of ABHD11-AS1 suppressed the progression of TNBC via upregulation of miR-199a-5p. The data of the present study may provide novel directions and a theoretical basis for TNBC treatment.