Identification of RNA-splicing factor Lsm12 as a novel tumor-associated gene and a potent biomarker in Oral Squamous Cell Carcinoma (OSCC)

Reovirus infection induces transcriptome-wide unique A-to-I editing changes in the murine fibroblasts

The conversion of Adenosine (A) to Inosine (I), by Adenosine Deaminases Acting on RNA or ADARs, is an essential post-transcriptional modification that contributes to proteome diversity and regulation in metazoans including humans. In addition to its transcriptome-regulating role, ADARs also play a major part in immune response to viral infection, where an interferon response activates interferon-stimulated genes, such as ADARp150, in turn dynamically regulating host-virus interactions. A previous report has shown that infection from reoviruses, despite strong activation of ADARp150, does not influence the editing of some of the major known editing targets, while likely editing others, suggesting a potentially nuanced editing pattern that may depend on different factors. However, the results were based on a handful of selected editing sites and did not cover the entire transcriptome. Thus, to determine whether and how reovirus infection specifically affects host ADAR editing patterns, we analyzed a publicly available deep-sequenced RNA-seq dataset, from murine fibroblasts infected with wild-type and mutant reovirus strains that allowed us to examine changes in editing patterns on a transcriptome-wide scale. To the best of our knowledge, this is the first transcriptome-wide report on host editing changes after reovirus infection. Our results demonstrate that reovirus infection induces unique nuanced editing changes in the host, including introducing sites uniquely edited in infected samples. Genes with edited sites are overrepresented in pathways related to immune regulation, cellular signaling, metabolism, and growth. Moreover, a shift in editing targets has also been observed, where the same genes are edited in infection and control conditions but at different sites, or where the editing rate is increased for some and decreased for other differential targets, supporting the hypothesis of dynamic and condition-specific editing by ADARs.

Sm-like 5 knockdown inhibits proliferation and promotes apoptosis of colon cancer cells by upregulating p53, CDKN1A and TNFRSF10B

BACKGROUND

The role of Sm-like 5 (LSM5) in colon cancer has not been determined. In this study, we investigated the role of LSM5 in progression of colon cancer and the potential underlying mechanism involved.

AIM

To determine the role of LSM5 in the progression of colon cancer and the potential underlying mechanism involved.

METHODS

The Gene Expression Profiling Interactive Analysis database and the Human Protein Atlas website were used for LSM5 expression analysis and prognosis analysis. Real-time quantitative polymerase chain reaction and Western blotting were utilized to detect the expression of mRNAs and proteins. A lentivirus targeting LSM5 was constructed and transfected into colon cancer cells to silence LSM5 expression. Proliferation and apoptosis assays were also conducted to evaluate the growth of the colon cancer cells. Human GeneChip assay and bioinformatics analysis were performed to identify the potential underlying mechanism of LSM5 in colon cancer.

RESULTS

LSM5 was highly expressed in tumor tissue and colon cancer cells. A high expression level of LSM5 was related to poor prognosis in patients with colon cancer. Knockdown of LSM5 suppressed proliferation and promoted apoptosis in colon cancer cells. Silencing of LSM5 also facilitates the expression of p53, cyclin-dependent kinase inhibitor 1A (CDKN1A) and tumor necrosis factor receptor superfamily 10B (TNFRSF10B). The inhibitory effect of LSM5 knockdown on the growth of colon cancer cells was associated with the upregulation of p53, CDKN1A and TNFRSF10B.

CONCLUSION

LSM5 knockdown inhibited the proliferation and facilitated the apoptosis of colon cancer cells by upregulating p53, CDKN1A and TNFRSF10B.

Sm-like 5 knockdown inhibits proliferation and promotes apoptosis of colon cancer cells by upregulating p53, CDKN1A and TNFRSF10B

BACKGROUND

The role of Sm-like 5 (LSM5) in colon cancer has not been determined. In this study, we investigated the role of LSM5 in progression of colon cancer and the potential underlying mechanism involved.

AIM

To determine the role of LSM5 in the progression of colon cancer and the potential underlying mechanism involved.

METHODS

The Gene Expression Profiling Interactive Analysis database and the Human Protein Atlas website were used for LSM5 expression analysis and prognosis analysis. Real-time quantitative polymerase chain reaction and Western blotting were utilized to detect the expression of mRNAs and proteins. A lentivirus targeting LSM5 was constructed and transfected into colon cancer cells to silence LSM5 expression. Proliferation and apoptosis assays were also conducted to evaluate the growth of the colon cancer cells. Human GeneChip assay and bioinformatics analysis were performed to identify the potential underlying mechanism of LSM5 in colon cancer.

RESULTS

LSM5 was highly expressed in tumor tissue and colon cancer cells. A high expression level of LSM5 was related to poor prognosis in patients with colon cancer. Knockdown of LSM5 suppressed proliferation and promoted apoptosis in colon cancer cells. Silencing of LSM5 also facilitates the expression of p53, cyclin-dependent kinase inhibitor 1A (CDKN1A) and tumor necrosis factor receptor superfamily 10B (TNFRSF10B). The inhibitory effect of LSM5 knockdown on the growth of colon cancer cells was associated with the upregulation of p53, CDKN1A and TNFRSF10B.

CONCLUSION

LSM5 knockdown inhibited the proliferation and facilitated the apoptosis of colon cancer cells by upregulating p53, CDKN1A and TNFRSF10B.

Butein inhibits oral squamous cell carcinoma growth via promoting MCL-1 ubiquitination

Oral squamous cell carcinoma (OSCC) is the most common malignant head and neck carcinoma type. Myeloid cell leukemia-1 (MCL-1), an anti-apoptotic BCL-1 protein, has been verified to be among the most highly upregulated pathologic proteins in human cancers linked to tumor relapse, poor prognosis and therapeutic resistance. Herein, therapeutic targeting MCL-1 is an attractive focus for cancer treatment. The present study found that butein, a potential phytochemical compound, exerted profound antitumor effects on OSCC cells. Butein treatment significantly inhibited cell viability, proliferation capacity and colony formation ability, and activated cell apoptotic process. Further potential mechanism investigation showed that promoting MCL-1 ubiquitination and degradation is the major reason for butein-mediated OSCC cell cytotoxicity. Our results uncovered that butein could facilitate E3 ligase FBW7 combined with MCL-1, which contributed to an increase in the ubiquitination of MCL-1 Ub-K48 and degradation. The results of both in vitro cell experiments and in vivo xenograft models imply a critical antitumor function of butein with the well-tolerated feature, and it might be an attractive and promising agent for OSCC treatment.

Alternative Splicing Landscape of Head and Neck Squamous Cell Carcinoma

Head and neck malignancies are a significant global health concern, with head and neck squamous cell carcinoma (HNSCC) being the sixth most common cancer worldwide accounting for > 90% of cases. In recent years, there has been growing recognition of the potential role of alternative splicing (AS) in the etiology of cancer. Increasing evidence suggests that AS is associated with various aspects of cancer progression, including tumor occurrence, invasion, metastasis, and drug resistance. Additionally, AS is involved in shaping the tumor microenvironment, which plays a crucial role in tumor development and response to therapy. AS can influence the expression of factors involved in angiogenesis, immune response, and extracellular matrix remodeling, all of which contribute to the formation of a supportive microenvironment for tumor growth. Exploring the mechanism of AS events in HNSCC could provide insights into the development and progression of this cancer, as well as its interaction with the tumor microenvironment. Understanding how AS contributes to the molecular changes in HNSCC cells and influences the tumor microenvironment could lead to the identification of new therapeutic targets. Targeted chemotherapy and immunotherapy strategies tailored to the specific AS patterns in HNSCC could potentially improve treatment outcomes and reduce side effects. This review explores the concept, types, processes, and technological advancements of AS, focusing on its role in the initiation, progression, treatment, and prognosis of HNSCC.

Targeted down-regulation of SRSF1 exerts anti-cancer activity in OSCC through impairing lysosomal function and autophagy

Oral squamous cell carcinoma (OSCC) is a common cancer of the head and neck. Despite ongoing efforts, there remains a dearth of targeted drugs capable of effectively inhibiting OSCC growth. As the earliest discovered proto-oncogene in the SRSF family, targeted inhibition of serine/arginine-rich splicing factor 1 (SRSF1) plays an important role in tumor suppression. However, the expression, function, and mechanism of SRSF1 in OSCC have not been comprehensively reported. This study retrospectively analyzed clinical samples from OSCC patients and discovered a significant correlation between the SRSF1 expression level and poor prognosis. In vitro experimentation demonstrated that SRSF1 knockdown inhibited OSCC growth, survival, lysosomal biogenesis and autophagy. To confirm the significance of lysosomal function and autophagy in the regulation of OSCC growth by SRSF1, cell rescue models were constructed. The aforementioned findings were subsequently validated in xenograft models. Ultimately, targeted knockdown of SRSF1 was found to significantly suppress OSCC growth by impeding lysosomal biogenesis and autophagy.

NAADP-binding proteins - Linking NAADP signaling to cancer and immunity

NAADP is one of the most potent calcium mobilizing second messengers. Only recently, two NAADP-binding proteins have been identified: HN1L/JPT2 and LSM12. Further, ASPDH was suggested as a less selective binding partner. Apart from this newly uncovered link, little is known about the shared mechanisms between these proteins. The aim of this review is to assess potential functional connections between NAADP and its binding proteins. We here give a description of two major links. For one, HN1L/JPT2 and LSM12 both have potent oncogenic functions in several cancer types. Second, they are involved in similar cellular pathways in both cancer and immunity.

FOXM1a Isoform of Oncogene FOXM1 Is a Tumor Suppressor Suppressed by hnRNP C in Oral Squamous Cell Carcinoma

FOXM1 is an oncogenic transcriptional factor and includes several isoforms generated by alternative splicing. Inclusion of alternative exon 9 produces FOXM1a, a transcriptionally inactive isoform. However, the role of FOXM1a in tumorigenesis remains unknown. In addition, the regulatory mechanisms of exon 9 splicing are also unclear. In the present study, we found that overexpression of FOXM1a significantly reduced cell proliferation and colony formation of oral squamous cell carcinoma (OSCC) cell proliferation in vitro. Importantly, OSCC cells with FOXM1a overexpression showed significantly slower tumor formation in nude mice. Moreover, we identified a U-rich exonic splicing suppressor (ESS) which is responsible for exon 9 skipping. Splicing factor heterogeneous nuclear ribonucleoprotein C (hnRNP C) can bind to the ESS and suppress exon 9 inclusion and FOXM1a expression. Silence of hnRNP C also significantly suppresses OSCC cell proliferation. HnRNP C is significantly co-expressed with FOXM1 in cancers. Our study uncovered a novel regulatory mechanism of oncogene FOXM1 expression in OSCC.

LINC00173 blocks GATA6-mediated transcription of COL5A1 to affect malignant development of oral squamous cell carcinoma

BACKGROUND

Aberrant expression of collagen type V alpha 1 chain (COL5A1) has been linked to several forms of human cancers. In this work, we focused on the interaction of the LINC00173/GATA binding protein 6 (GATA6)/COL5A1 axis in the malignant property of oral squamous cell carcinoma (OSCC) cells.

METHODS

We analyzed six publicly accessible datasets GSE160042, GSE74530, GSE138206, GSE23558, GSE31853 and GSE146483 to identify aberrantly expressed genes in OSCC. The expression of COL5A1 in OSCC tissues and cell lines was examined by reverse transcription-quantitative polymerase chain reaction and/or immunohistochemistry. The regulatory mechanism responsible for COL5A1 transcription was predicted via bioinformatics systems, and the interactions of LINC00173, GATA6, and COL5A1 were identified by immunoprecipitation and luciferase assays. Overexpression or downregulation of COL5A1, GATA6, and LINC00173 were induced in OSCC cell lines to determine their roles in the malignant phenotype of the OSCC cells in vitro and in vivo.

RESULTS

COL5A1 showed elevated expression in OSCC tissues and cells. The COLA51 knockdown suppressed proliferation, migration and invasiveness, apoptosis resistance, and pro-angiogenic ability of OSCC cells, and it suppressed the growth and dissemination of xenograft tumors in vivo. GATA6 bound to COL5A1 promoter to activate its transcription, whereas LINC00173 bound to GATA6 to block this transcriptional activation. Overexpression of GATA6 or COL5A1 promoted the malignant phenotype of the OSCC cells, which were blocked upon LINC00173 upregulation.

CONCLUSION

This work demonstrates that LINC00173 blocks GATA6-mediated transcription of COL5A1 to affect malignant development of OSCC.

LSM12 facilitates the progression of colorectal cancer by activating the WNT/CTNNB1 signaling pathway

Aberrant activation of the WNT signaling pathway is a joint event in colorectal cancer (CRC), but the molecular mechanism is still unclear. Recently, RNA-splicing factor LSM12 (like-Sm protein 12) is highly expressed in CRC tissues. This study aimed to verify whether LSM12 is involved in regulating CRC progression via regulating the WNT signaling pathway. Here, we found that LSM12 is highly expressed in CRC patient-derived tissues and cells. LSM12 is involved in the proliferation, invasion, and apoptosis of CRC cells, similar to the function of WNT signaling in CRC. Furthermore, protein interaction simulation and biochemical experiments proved that LSM12 directly binds to CTNNB1 (also known as β-Catenin) and regulates its protein stability to affect the CTTNB1-LEF1-TCF1 transcriptional complex formation and the associated WNT downstream signaling pathway. LSM12 depletion in CRC cells decreased the in vivo tumor growth through repression of cancer cell growth and acceleration of cancer cell apoptosis. Taken together, we suggest that the high expression of LSM12 is a novel factor leading to aberrant WNT signaling activation, and that strategies targeting this molecular mechanism may contribute to developing a new therapeutic method for CRC.

Integrating Cutting-Edge Methods to Oral Cancer Screening, Analysis, and Prognosis

Oral cancer (OC) has become a significant barrier to health worldwide due to its high morbidity and mortality rates. OC is among the most prevalent types of cancer that affect the head and neck region, and the overall survival rate at 5 years is still around 50%. Moreover, it is a multifactorial malignancy instigated by genetic and epigenetic variabilities, and molecular heterogeneity makes it a complex malignancy. Oral potentially malignant disorders (OPMDs) are often the first warning signs of OC, although it is challenging to predict which cases will develop into malignancies. Visual oral examination and histological examination are still the standard initial steps in diagnosing oral lesions; however, these approaches have limitations that might lead to late diagnosis of OC or missed diagnosis of OPMDs in high-risk individuals. The objective of this review is to present a comprehensive overview of the currently used novel techniques viz., liquid biopsy, next-generation sequencing (NGS), microarray, nanotechnology, lab-on-a-chip (LOC) or microfluidics, and artificial intelligence (AI) for the clinical diagnostics and management of this malignancy. The potential of these novel techniques in expanding OC diagnostics and clinical management is also reviewed.

Emerging roles of alternative RNA splicing in oral squamous cell carcinoma

Alternative RNA splicing (ARS) is an essential and tightly regulated cellular process of post-transcriptional regulation of pre-mRNA. It produces multiple isoforms and may encode proteins with different or even opposite functions. The dysregulated ARS of pre-mRNA contributes to the development of many cancer types, including oral squamous cell carcinoma (OSCC), and may serve as a biomarker for the diagnosis and prognosis of OSCC and an attractive therapeutic target. ARS is mainly regulated by splicing factors, whose expression is also often dysregulated in OSCC and involved in tumorigenesis. This review focuses on the expression and roles of splicing factors in OSCC, the alternative RNA splicing events associated with OSCC, and recent advances in therapeutic approaches that target ARS.