STRA6 Expression Serves as a Prognostic Biomarker of Gastric Cancer

Inhibition of STRA6 suppresses NSCLC growth via blocking STAT3/SREBP-1c axis-mediated lipogenesis

Dysregulation in lipid metabolism is among the most prominent metabolic alterations in cancer. Stimulated by retinoic acid 6 (STRA6), a vitamin A transporter has shown to be involved in the pathogenesis of cancers. Nevertheless, the function of STRA6 in non-small cell lung cancer (NSCLC) progression remains undefined. We obtained cancer and adjacent tissues from NSCLC patients and conducted functional experiments on STRA6 on NSCLC cell lines and mice. High STRA6 expression is correlated with poor prognosis in patients with NSCLC. Results from in vitro and in vivo animal studies showed that STRA6 knockdown suppressed the proliferation, migration, and invasion of NSCLC cells in vitro and tumor growth in vivo through regulation of lipid synthesis. Mechanistically, STRA6 activated a Janus kinase 2/signal transducer and activator of transcription 3 (JAK2-STAT3) signaling cascade which inducing the expression of STAT3 target gene. By inducing the expression of the target gene of STAT3, sterol regulatory element binding protein 1 (SREBP-1), STRA6 promotes SREBP-1-mediated adipogenesis and provides energy for NSCLC cell growth. Our study uncovers a novel STRA6/STAT3/SREBP-1 regulatory axis that enhances NSCLC metastasis by reprogramming of lipid metabolism. These results demonstrate the potential use of STRA6 as a biomarker for diagnosing NSCLC, which may therefore potentially serve as a therapeutic target for NSCLC.

Determining the effect of long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) on the transcriptome profile in cervical cancer cell lines

This study investigates the role of the long non-coding RNA Maternally Expressed Gene3 (lncRNA MEG3) gene in cervical cancer, as evidenced by its downregulation in cancerous cell lines. The study demonstrates the effects of the overexpression of lncRNA MEG3 in cervical cancer cell lines, particularly in C33A and CaSki. Through comprehensive analyses, including Next-Generation Sequencing (NGS), alterations in global mRNA expression were analyzed. In C33A cells, 67 genes were upregulated, while 303 genes were downregulated. Similarly, in CaSki cells, 221 genes showed upregulation and 248 genes displayed downregulation. Gene ontology and KEGG pathway analyses were conducted to gain insight into potential mechanisms. Furthermore, the study delves into gene regulatory networks, uncovering intricate interactions among genes. The RNA sequencing data were confirmed for eight genes: PAX3, EGR2, ROR1, NRP1, OAS2, STRA6, CA9, and EDN2 by Real-time PCR. The findings illuminate the complex landscape of gene expression alterations and pathways impacted by the overexpression of lncRNA MEG3. The impact of MEG3 on the overall cervical cancer cells' mRNA profile is reported for the first time. New biomarkers for the prognosis of cervical cancer are also reported in this study. Moreover, identifying specific genes within the regulatory networks provides valuable insights into potential therapeutic targets for managing cervical cancer.

Endoplasmic reticulum stress as a target for retinoids in cancer treatment

Retinoids, natural and synthetic derivatives of vitamin A, have various regulatory activities including controlling cellular proliferation, differentiation, and death. Furthermore, they have been used to treat specific cancers with satisfying results. Nevertheless, retinoids have yet to be converted into effective systemic therapies for the majority of tumor types. Regulation of unfolded protein response signaling, and persistent activation of endoplasmic reticulum stress (ER-stress) are promising treatment methods for cancer. The present article reviews the current understanding of how vitamin A and its derivatives may aid to cause ER-stress-activated apoptosis, as well as therapeutic options for exploiting ER-stress for achieving beneficial goal. The therapeutic use of some retinoids discussed in this article was related to decreased disease recurrence and improved therapeutic outcomes via ER-stress activation and promotion, indicating that retinoids may play an important role in cancer treatment and prevention. More research is needed to expand the use of vitamin A derivatives in cancer therapy, either alone or in combination with unfolded protein response inducers.

Glycolysis and tumor progression promoted by the m6A writer VIRMA via m6A-dependent upregulation of STRA6 in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies, highlighting the urgent need to elucidate the underlying oncogenic mechanisms. VIRMA is a classic isoform of methyltransferases that participates in epigenetic transcriptomic modification in eukaryotic mRNAs. However, the exact roles of VIRMA in PDAC remain unclear. Here, we identified that VIRMA is highly expressed in PDAC, and histone modifications of the promoter may partly account for this dysregulation. Moreover, VIRMA is closely related to glycolysis and poor prognosis in PDAC. We further determined that STRA6 is a direct downstream target of VIRMA in PDAC by RNA sequencing (RNA-seq) and m6A sequencing (m6A-seq). VIRMA is involved in gene expression regulation via 3' UTR targeting of STRA6 mRNA. Furthermore, the m6A reader IGF2BP2 was shown to critically contribute to the stability of STRA6 mRNA. We describe the role of VIRMA in promoting signaling via the STRA6/STAT3 axis, which results in increased levels of HIF-1α, a key activator of glycolysis. In vivo and in vitro experiments reveal that the VIRMA-STRA6-STAT3-HIF-1α axis plays an instrumental role in glycolysis and tumor progression in PDAC. In conclusion, we demonstrate that VIRMA can increase glycolysis in PDAC by upregulating STRA6, a cell surface membrane protein that stimulates the STAT3 pathway, thereby activating HIF-1α and leading to pancreatic cancer malignancy. Overall, our data strongly suggest that the VIRMA-STRA6-STAT3-HIF-1α axis is a viable therapeutic target in PDAC.

ANLN Promotes the Proliferation and Migration of Gallbladder Cancer Cells via STRA6-Mediated Activation of PI3K/AKT Signaling

The ANLN gene encodes anillin, a protein that binds to actin. Recent research has identified ANLN's function in the initiation and advancement of different cancers. However, its impact on gallbladder cancer (GBC) remains unexplored. This study aimed to elucidate its possible molecular mechanisms in GBC. ANLN expression was assessed using quantitative real-time polymerase chain reaction (QRT-PCR), Western blotting (WB), and immunohistochemistry (IHC), revealing elevated levels in GBC tissues. ANLN knockdown resulted in the inhibition of cell proliferation and migration, leading to apoptosis and cell cycle arrest. Conversely, ANLN overexpression had the opposite effects on GBC cells. In vivo experiments confirmed that ANLN knockdown inhibited GBC cell growth. RNA-seq and bioinformatics analysis revealed ANLN's function in activating the PI3K/AKT signaling pathway. We further confirmed that ANLN could upregulate STRA6 expression, which activated PI3K/AKT signaling to enhance the growth and movement of GBC cells. These findings demonstrate ANLN's involvement in GBC initiation and progression, suggesting its potential as a novel target for GBC.

Analysis of immunotherapeutic response-related signatures in esophageal squamous-cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most common and lethal malignant diseases. Immunotherapy has been widely studied and has exhibited potential in ESCC treatment. However, there are only a portion of ESCC patients have benefited from immunotherapy. We herein identified immunotherapeutic response-related signatures (IRRS) and evaluated their performance in ESCC prognosis and immunotherapeutic responsiveness.

Methods

We constructed an IRRS using the gene expression data of 274 ESCC patients based on y -30significantly differentially expressed genes, which were compared responders and non-responders from various patient cohorts treated with immunotherapy. Survival analysis was performed in both the GSE53625 and TCGA-ESCC cohorts. We also explored the differences in the tumor microenvironment between the high-IRRS and low-IRRS score groups using single-cell data as a reference. Three immunotherapy cohorts were used to verify the value of the IRRS in predicting immunotherapy response.

Results

Twelve immunotherapy-related genes were selected to construct a signature score and were validated as independent prognostic predictors for patients with ESCC. Patients with high IRRS scores exhibited an immunosuppressive phenotype. Therefore, patients with low IRRS scores may benefit from immunotherapy.

Conclusions

IRRS score is a biomarker for immunotherapy response and prognosis of ESCC.

STRA6 Promotes Thyroid Carcinoma Progression via Activation of the ILK/AKT/mTOR Axis in Cells and Female Nude Mice

BACKGROUND

Metastasis has emerged to be an important cause for poor prognosis of thyroid carcinoma (TC) and its molecular mechanisms are not fully understood. STRA6 is a multifunctional membrane protein widely expressed in embryonic and adult tissues. The function and mechanism of STRA6 in TC remain elusive.

OBJECTIVE

We aimed to explore the role of STRA6 in TC progression and provide a therapeutic target for TC.

METHODS

The expression and clinicopathological relevance of STRA6 were explored in TC. Stable STRA6-knockdown TC cells were established and used to determine the biological function of STRA6 in vitro and in vivo. RNA sequencing and co-immunoprecipitation were performed to unveil the molecular mechanism of STRA6 in TC progression. The potential of STRA6 as a therapeutic target was evaluated by lipid nanoparticles (LNPs) containing siRNA.

RESULTS

STRA6 was upregulated in TC and correlated with aggressive clinicopathological features, including extrathyroidal extension and lymph node metastasis, which contributed to the poor prognosis of TC. STRA6 facilitated TC progression by enhancing proliferation and metastasis in vitro and in vivo. Mechanistically, STRA6 could interact with integrin-linked kinase (ILK) and subsequently activate the protein kinase B/mechanistic target of rapamycin (AKT/mTOR) signaling pathway. We further unveiled that STRA6 reprogrammed lipid metabolism through SREBP1, which was crucial for the metastasis of TC. Moreover, STRA6 siRNA delivered by LNPs significantly inhibited cell growth in xenograft tumor models.

CONCLUSIONS

Our study demonstrates the critical roles of STRA6 contributing to TC progression via the ILK/AKT/mTOR axis, which may provide a novel prognostic marker as well as a promising therapeutic target for aggressive TC.

STRA6 regulates tumor immune microenvironment and is a prognostic marker in BRAF-mutant papillary thyroid carcinoma

BACKGROUND

BRAF mutation is one of the most common genetic alterations contributing to the initiation and progression of papillary thyroid carcinoma (PTC). However, the prognostic value of BRAF mutation for PTC is limited. Novel markers are needed to identify BRAF-mutant patients with poor prognosis.

METHODS

Transcriptional expression data were downloaded from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Pathway enrichment was performed by Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and gene set enrichment analysis (GSEA). Protein-protein interaction networks were predicted by the GeneMANIA. The correlation between STRA6 expression and immune infiltration was analyzed by tumor immune estimation resource (TIMER) and tumor-immune system interaction database (TISIDB). Immunohistochemistry was used to detect the STRA6 protein expression level of PTC. Infiltration of regulatory T cells (Tregs) and CD8+ T cells in tumor samples were analyzed by fluorescent multiplex immunohistochemistry.

RESULTS

In BRAF-mutant PTC, STRA6 was extremely upregulated and predicted unfavorable survival, which was an independent risk factor for increased mortality risk. Bioinformatic analyses indicated that STRA6 might activate the MAPK pathway synergistically with BRAF^V600E. The expression of STRA6 was associated with immune infiltrates and T cell exhaustion. Fluorescent multiplex immunohistochemistry showed that STRA6 increased Tregs abundance and decreased CD8+ T cells infiltration in PTC. Moreover, STRA6 promoted epithelial-mesenchymal transition via increased cancer-associated fibroblasts infiltration.

CONCLUSIONS

Our study demonstrates STRA6 may serve as a prognostic marker for BRAF-mutated PTC, which may drive thyroid carcinogenesis via activation of oncogenic pathway and regulation of tumor immunosuppressive microenvironment.

Major Histocompatibility Complex Class I-Related Chain A (MICA) Allelic Variants Associate With Susceptibility and Prognosis of Gastric Cancer

Gastric cancer (GC) is the fifth most prevalent type of cancer worldwide. Gastric tumor cells express MICA protein, a ligand to NKG2D receptor that triggers natural killer (NK) cells effector functions for early tumor elimination. MICA gene is highly polymorphic, thus originating alleles that encode protein variants with a controversial role in cancer. The main goal of this work was to study MICA gene polymorphisms and their relationship with the susceptibility and prognosis of GC. Fifty patients with GC and 50 healthy volunteers were included in this study. MICA alleles were identified using Sanger sequencing methods. The analysis of MICA gene sequence revealed 13 MICA sequences and 5 MICA-short tandem repeats (STR) alleles in the studied cohorts We identified MICA^*002 (^*A9) as the most frequent allele in both, patients and controls, followed by MICA^*008 allele (^*A5.1). MICA^*009/049 allele was significantly associated with increased risk of GC (OR: 5.11 [95% CI: 1.39–18.74], p = 0.014). The analysis of MICA-STR alleles revealed a higher frequency of MICA^*A5 in healthy individuals than GC patients (OR = 0.34 [95% CI: 0.12–0.98], p = 0.046). Survival analysis after gastrectomy showed that patients with MICA^*002/002 or MICA^*002/004 alleles had significantly higher survival rates than those patients bearing MICA^*002/008 (p = 0.014) or MICA^*002/009 (MICA^*002/049) alleles (p = 0.040). The presence of threonine in the position MICA-181 (MICA^*009/049 allele) was more frequent in GC patients than controls (p = 0.023). Molecular analysis of MICA-181 showed that the presence of threonine provides greater mobility to the protein than arginine in the same position (MICA^*004), which could explain, at least in part, some immune evasion mechanisms developed by the tumor. In conclusion, our findings suggest that the study of MICA alleles is crucial to search for new therapeutic approaches and may be useful for the evaluation of risk and prognosis of GC and personalized therapy.