Suppression of JAK2/STAT3 Pathway by Notoginsenoside R1 Reduces Epithelial-Mesenchymal Transition in Non-small Cell Lung Cancer.

It has bene reported that a novel saponin-notoginsenoside R1 (NGR1) possesses strong anti-tumor activities. This study aimed to investigate the role and mechanism of NGR1 in non-small cell lung cancer (NSCLC). NSCLC cell viability, proliferation, migration, and invasiveness were assessed using the ex vivo assays. NSCLC xenograft mouse models were constructed to confirm the role of NGR1 in vivo. Epithelial-mesenchymal transition (EMT)-related proteins and key markers in the JAK2/STAT3 pathway were examined using immunoblotting and immunohistochemistry analyses. NGR1 treatment suppressed NSCLC cell growth ex vivo and in vivo. It also decreased the migratory and invasive capacities of NSCLC cells. Additionally, NGR1 increased E-cadherin expression and reduced N-cadherin, vimentin, and snail expression in TGF-ß1-treated NSCLC cells and xenograft tumors. JAK2/STAT3 pathway was inhibited by NGR1. Moreover, a specific inhibitor of JAK2, AG490, or STAT3 silencing significantly enhanced the effects of NGR1 against the EMT process in NSCLC cells. NGR1 restrains EMT process in NSCLC by inactivating JAK2/STAT3 signaling, suggesting the potential of NGR1 in anti-NSCLC therapy.

Lobetyolin inhibits cell proliferation and induces cell apoptosis by downregulating ASCT2 in gastric cancer.

Gastric cancer (GC) is a heterogeneous disease and is the fifth most common cancer worldwide. Lobetyolin, as a bioactive ingredient extracted from Codonopsis pilosula (Franch.) Nannf., has been reported to exert anti-tumor effects in several cancer types. This study was aimed to investigate the role of lobetyolin in GC and the associated mechanism. MKN-45 and MKN-28 cells were incubated with concentrations of lobetyolin for 24 h. The viability and survival of GC cells were evaluated by performing MTT assay. Glutamine uptake, Adenosine Triphosphate, reactive oxygen species (ROS), and glutathione levels were measured by corresponding kits. Apoptosis and mitochondrial membrane potential of GC cells were determined by flow cytometry. Alanine, serine, cysteine-preferring transporter 2 (ASCT2) and the AKT/GSK3ß/c-Myc pathway protein levels were examined by western blotting. Xenograft model and immunohistochemical staining were used to evaluate the pharmacological effects of lobetyolin in mice in vivo. We found that lobetyolin treatment suppressed the proliferative capacity of both MKN-45 and MKN-28 cells in a concentration-dependent manner. Lobetyolin reduced the uptake of glutamine and downregulated the expression levels of ASCT2 in GC cells and xenograft tumors. Lobetyolin effectively restrained the growth of tumors in vivo. In addition, lobetyolin induced the accumulation of ROS to attenuate mitochondria-mediated apoptosis via downregulation of ASCT2 expression. Lobetyolin promoted the phosphorylation of c-Myc and suppressed the phosphorylation of GSK3ß and AKT in both MKN-45 and MKN-28 cells. The level of total Nrf2 protein was reduced after lobetyolin treatment. Overall, lobetyolin exerts anti-cancer effects by repressing cell proliferation and inducing cell apoptosis via downregulation of ASCT2 in GC.

LncRNA GSCAR promotes glioma stem cell maintenance via stabilizing SOX2 expression.

Gliomas are the most aggressive type of malignant brain tumors. Recent studies have demonstrated that the existence of glioma stem cells (GSCs) is critical for glioma recurrence, metastasis, and chemo- or radio-therapy resistance. Temozolomide (TMZ) has been used as an initial therapy for gliomas. However, the overall survival time is still limiting due to the lack of effective targets and treatment options. Therefore, identifying novel biomarkers for gliomas, especially for GSCs, is important to improve the clinical outcome in the future. In this study, we identify a human-specific long non-coding RNA (lncRNA, ENSG00000250377), termed GSCAR (glioma stem cell associated lncRNA), which is highly expressed in glioma cancerous tissues and cell lines. We reveal that GSCAR positively correlates with tumor grade. Glioma patients with GSCAR high expression exhibit shortened overall survival time, compared to patients with GSCAR low expression. Furthermore, we show that GSCAR knockdown by shRNAs or antisense oligonucleotide (ASO) reduces tumor cell proliferation, migration and xenograft tumor formation abilities. Mechanistic study shows that GSCAR acts as a ceRNA (competing endogenous RNA) for miR-6760-5p to promote the expression of oncogene SRSF1 (serine and arginine rich splicing factor 1). In addition, GSCAR mediates the protein complex formation between DHX9 (DExH-Box helicase 9) and IGF2BP2 (insulin-like growth factor 2 mRNA-binding protein 2), leading to the stabilization of SOX2 (sex-determining region Y-box 2) mRNA and then the transcriptional activation of GSCAR. Depleting GSCAR reduces SOX2 expression and GSC self-renewal ability, but promotes tumor cell responses to TMZ. These findings uncover that GSCAR/miR-6760-5p/SRSF1 axis and GSCAR/DHX9-IGF2BP2/SOX2 positive feedback loop are critical for glioma progression, which could be used as prognostic biomarkers and therapeutic targets in the future.

Corrigendum: Long non-coding RNA-TMPO-AS1 as ceRNA binding to let-7c-5p upregulates STRIP2 expression and predicts poor prognosis in lung adenocarcinoma.

[This corrects the article DOI: 10.3389/fonc.2022.921200.].

Long Non-Coding RNA-TMPO-AS1 as ceRNA Binding to let-7c-5p Upregulates STRIP2 Expression and Predicts Poor Prognosis in Lung Adenocarcinoma.

Background: Striatin-interacting protein 2 (STRIP2), also called Fam40b, has been reported to regulate tumor cell growth. But the role of STRIP2 in lung adenocarcinoma (LUAD) has not been discovered clearly. Thus, the aim of our study is to explore the function and underlying mechanism of STRIP2 in LUAD. Methods: Expression of STRIP2 was determined using the Cancer Genome Atlas (TCGA), GTEx, Ualcan, and the Human Protein Altas databases. The Correlation of STRIP2 and survival was detected by PrognoScan and Kaplan-Meier plotter databases. Besides, the correlation between STRIP2 expression and tumor immune infiltration as well as immune checkpoints were analyzed by the ssGSEA method. The biological function of STRIP2 and its co-expression genes was determined by gene ontology (GO) and Genes and Genomes (KEGG), respectively. Finally, the expression level and biological function of STRIP2 in LUAD were determined by qPCR, CCK8, transwell, and wound healing assays. Results: This manuscript revealed a significantly increased expression of mRNA and protein of STRIP2 in lung adenocarcinoma compared with the adjacent normal tissues. GEO and Kaplan-Meier plotter databases showed higher STRIP2 expression levels were correlated with poor prognosis survival of LUAD. Moreover, Cox regression analysis suggested that a higher STRIP2 level served as an independent risk factor in predicting deteriorative overall survival (OS) for LUAD patients. SsGSEA results showed STRIP2 expression level was positively correlated with infiltrating levels of Th2 cells in LUAD. Lastly, GO analysis indicated the biological processes were enriched in nuclear division and positive regulation of the cell cycle. KEGG signaling pathway analysis showed STRIP2 was correlated with the MAPK signaling pathway and the TNF signaling pathway. The GSEA database showed that STRIP2 was positively associated with the epithelial-mesenchymal transition, cell cycle, and TNF signaling pathway. The QRT-PCR assay showed that STRIP2 was upregulated in LUAD cell lines. Cell proliferation and migration were inhibited in LUAD by knockdown of STRIP2. Moreover, we confirmed that the TMPO-AS1/let-7c-5p/STRIP2 network regulates STRIP2 overexpression in LUAD and is associated with poor prognosis. Conclusion: Our findings indicated that STRIP2 acted as a crucial oncogene in LUAD and was correlated with unfavorable survival and tumor infiltration inflation.

Identification and Validation of Long Non-Coding RNA LCIIAR as a Biomarker in LUAD.

Lung cancer is the leading cause of cancer-related death worldwide. Therapies for lung cancer have relatively poor outcomes and need to be improved. Lung cancer immune cell infiltration associated RNA (LCIIAR) is a long noncoding RNA (lncRNA), which is overexpressed in human cancers. However, the clinical significance and functional role of LCIIAR in Lung Adenocarcinoma remain unclear. Here, we identified a novel long non-coding RNA (ENSG00000256802), termed LCIIAR (lung cancer immune cell infiltration associated lncRNA), up-regulated in lung cancer tissue and cell lines. We show that increase LCIIAR expression correlated with poor clinical stage and adverse clinical outcomes and that could also serve as an independent unfavorable prognostic factor in patients with Lung Adenocarcinima. GSEA analysis demonstrated that LCIIAR is mainly involved in the regulation of the immune response. We uncovered that elevate LCIIAR expression positively correlated with immune infiltration and immune modulator in Lung Adenocarcinoma. More importantly, we confirmed that silencing of LCIIAR expression significantly inhibits the proliferation, and migration abilities of these tumour cells. We also demonstrated that the LCIIAR/hsa-miR184/SLC16A3/CDCP1 network regulates SLC16A3/CDCP1 overexpression in and is associated with poor prognosis in this tumour. Therefore our findings revealed the critical role of LCIIAR in Lung Adenocarcinoma progression, which may also serve as a prognostic biomarker and novel therapeutic target.

MicroRNA-125b-5p Correlates With Prognosis and Lung Adenocarcinoma Progression.

A growing number of studies have focused on investigating microRNAs as crucial regulators in the progression of multiple cancer types. Nevertheless, the biological effects and immunological role of miR-125b-5p in non-small cell lung cancer (lung adenocarcinoma, LUAD) have not been determined. The present study aimed to examine the function of miR-125b-5p on cell proliferation and the outcomes of LUAD patients. We utilized diverse public databases in the analysis of the expression, prognosis, diagnostic value, and immune role of miR-125b-5p in non-small cell lung cancer. The growth curve, colony formation, flow cytometry, and Transwell and invasion assays were utilized to determine the function of miR-125b-5p in LUAD progression. In this study, we found that miR-125b-5p was decreased in LUAD and correlated with poor prognosis. Pathway analyses revealed that miR-125b-5p was mainly involved in cell proliferation and immune regulation. Moreover, in vitro experiments indicated that the overexpression of miR-125b-5p significantly inhibited cell proliferation, migration, and invasion and induced cell apoptosis of LUAD. Finally, we discovered that miR-125b-5p correlated with immune cell infiltration. In summary, these results demonstrated that miR-125b-5p serves as a prognostic marker and a therapeutic target for LUAD.

RETSAT Mutation Selected for Hypoxia Adaptation Inhibits Tumor Growth.

Hypoxia occurs not only in natural environments including high altitude, underground burrows and deep sea, but also in human pathological conditions, such as hypoxic solid tumors. It has been well documented that hypoxia related signaling pathway is associated with a poor clinical outcome. Our group has recently identified multiple novel genes critical for solid tumor growth comparing the genome-wide convergent/parallel sequence evolution of highland mammals. Among them, a single mutation on the retinol saturase gene (RETSAT) containing amino acid switch from glutamine (Q) to arginine (R) at the position 247 was identified. Here, we demonstrate that RETSAT is mostly downregulated in multiple types of human cancers, whose lower expression correlates with worse clinical outcome. We show that higher expression of RETSAT is positively associated with immune infiltration in different human cancers. Furthermore, we identify that the promoter region of RETSAT is highly methylated, which leads to its decreased expressions in tumor tissues comparing to normal tissues. Furthermore, we show that RETSAT knockdown promotes, while its overexpression inhibits, the cell proliferation ability of mouse embryonic fibroblasts (MEFs) and B16 in vitro. In addition, the mice carrying homozygous Q247R mutation (RETSATR/R) is more resistant to xenograft tumor formation, as well as DMBA/TPA induced cutaneous keratinocyte carcinoma formation, compared to littermate wild-type (RETSATQ/Q) mice. Mechanistic study uncovers that the oncogenic factor, the prolyl isomerase (PPIase) Pin1 and its related downstream signaling pathway, were both markedly repressed in the mutant mice compared to the wild-type mice. In summary, these results suggest that interdisciplinary study between evolution and tumor biology can facilitate identification of novel molecular events essential for hypoxic solid tumor growth in the future.