Long non-coding RNA MAFG-AS1 promotes proliferation and metastasis of breast cancer by modulating STC2 pathway

STC2 suppresses triple-negative breast cancer migration and invasion by inhibition on EMT and promotion on cell apoptosis

To investigate the effects of higher cellular stanniocalcin 2 (STC2) on suppressing the migration and invasion but promoting the apoptosis of triple-negative breast cancer (TNBC). STC2 in TNBC and the para-carcinoma tissues were analyzed by immunohistochemistry (IHC), while the mRNA level was measured by qPCR. Over-expressing or silencing STC2 was established in MDA-MB-231 cells. Epithelial mesenchymal transition (EMT) related proteins, cell migration, invasion, proliferation and apoptosis were detected. MDA-MB-231 with over-expressing or silencing STC2 were injected into nude mice to formatting tumors, and then EMT related proteins were measured by IHC. Lower STC2 expressed in TNBC tissues than in the para-carcinoma tissues. Silencing STC2 promoted EMT of TNBC cell MDA-MB-231, as well as cell migration, invasion and proliferation, but suppressed MDA-MB-231 apoptosis, while over-expressing STC2 had the opposite results, which might be related to PKC/PI3K/AKT/mTOR pathway. STC2 was the protective gene in TNBC, by suppressing migration and invasion to inhibit MDA-MB-231 cell EMT but promote cell apoptosis, in order to suppress TNBC progression.

Stanniocalcin 2 Regulates Autophagy and Ferroptosis in Mammary Epithelial Cells of Dairy Cows Through the Mechanistic Target of Rapamycin Complex 1 Pathway

BACKGROUND

Stanniocalcin 2 (STC2), a glycoprotein hormone, is extensively expressed in various organs and tissues, particularly in the mammary gland. STC2 plays a crucial role in enabling cells to adapt to stress conditions and avert apoptosis. The efficiency of milk production is closely linked to both the quantity and quality of mammary cells. Yet, there remains a dearth of research on the impact of STC2 on mammary cells' activity in dairy cows.

OBJECTIVES

The objective of this study was to investigate the effects of STC2 on the viability of mammary epithelial cells in dairy cows and to elucidate the underlying mechanisms.

METHODS

First, the Gene Expression Profiling and Interactive Analysis database was employed to perform survival analysis on STC2 expression in relation to prognosis using The Cancer Genome Atlas and GETx data. Subsequently, the basic physical and chemical properties, gene expression, and potential signaling pathways involved in the growth of dairy cow mammary epithelial cells were determined using STC2 knockdown.

RESULTS

STC2 knockdown significantly suppressed autophagy in mammary epithelial cells of dairy cows. Moreover, STC2 knockdown upregulated glutathione peroxidase 4 protein expression, elicited an elevation in lipid ROS concentrations, and inhibited the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway, consequently repressing downstream genes involved in lipid synthesis regulated by mTORC1 and ultimately inducing ferroptosis.

CONCLUSIONS

The findings of our study suggest that STC2 suppresses autophagy and ferroptosis through the activation of mTORC1. Mechanically, STC2 exerts an inhibitory effect on ferroptosis by activating antioxidative stress-related proteins, such as glutathione peroxidase 4, to suppress lipid ROS production and stimulating the mTORC1 signaling pathway to enhance the expression of genes associated with lipid synthesis.

Implications in Cancer of Nuclear Micro RNAs, Long Non-Coding RNAs, and Circular RNAs Bound by PRC2 and FUS

The eukaryotic genome is mainly transcribed into non-coding RNAs (ncRNAs), including different RNA biotypes, such as micro RNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), among others. Although miRNAs are assumed to act primarily in the cytosol, mature miRNAs have been reported and functionally characterized in the nuclei of different cells. Further, lncRNAs are important regulators of different biological processes in the cell nucleus as part of different ribonucleoprotein complexes. CircRNAs constitute a relatively less-characterized RNA biotype that has a circular structure as result of a back-splicing process. However, circRNAs have recently attracted attention in different scientific fields due to their involvement in various biological processes and pathologies. In this review, we will summarize recent studies that link to cancer miRNAs that have been functionally characterized in the cell nucleus, as well as lncRNAs and circRNAs that are bound by core components of the polycomb repressive complex 2 (PRC2) or the protein fused in sarcoma (FUS), highlighting mechanistic aspects and their diagnostic and therapeutic potential.

Palbociclib sensitizes ER-positive breast cancer cells to fulvestrant by promoting the ubiquitin-mediated degradation of ER-α via SNHG17/Hippo-YAP axis

PURPOSE

Endocrine therapy is the anti-tumor therapy for human breast cancer but endocrine resistance was a major burden. It has been reported that Palbociclib and fulvestrant can be used in combination for the treatment of patients who are experiencing endocrine resistance. However, the underlying mechanism is unclear. In this study, we aimed to investigate the mechanism by which Palbocicilib affected ER-positive breast cancer, combined with fulvestrant.

METHODS

We first detected the effect of palbociclib on cell survival, growth and cycle distribution separately by MTT, colony formation and flow cytometry. Then SNHG17 was screened as palbociclib-targeted LncRNA by LncRNA-seq, and the SNHG17-targeted mRNAs were selected by mRNA-seq for further determination. Subsequently, the underlying mechanism by which palbociclib promoted the cytotoxicity of fulvestrant was confirmed by qRT-PCR, western blot, and immunoprecipitation. Eventually, the xenograft model and immunohistochemistry experiments were used to validate the sensitization effect of palbociclib on fulvestrant and its mechanism in vivo.

RESULTS

Palbociclib significantly enhanced the cytotoxicity of fulvestrant in fulvestrant-resistant breast cancer cell lines. Interestingly, this might be related to the lncRNA SNHG17 and the Hippo signaling pathway. And our subsequent western blotting experiments confirmed that overexpressing SNHG17 induced the down-regulation of LATS1 and up-regulated YAP expression. Furthermore, we found that the increased sensitivity of breast cancer cells was closely associated with the LATS1-mediated degradation of ER-α. The following animal experiments also indicated that overexpressing SNHG17 obviously impaired the anti-cancer effect of co-treatment of palbociclib and fulvestrant accompanied by decreased LATS1 and increased ER-α levels.

CONCLUSION

Palbociclib might sensitize the cytotoxicity of fulvestrant in ER-positive breast cancer cells by down-regulating SNHG17 expression, and then resulted in the LATS1-inactivated oncogene YAP and LATS1-mediated degradation of ER-α.

Carcinogenic roles of MAFG-AS1 in human cancers

The MAF bZIP transcription factor G-antisense RNA 1 (MAFG-AS1) is located on chromosome 17. MAFG-AS1 was upregulated in 15 human cancers. MAFG-AS1 not only suppresses 16 miRNAs but also directly impacts 22 protein-coding genes' expression. Notably, abnormal MAFG-AS1 expression is connected to clinicopathological characteristics and a worse prognosis in a variety of cancers. Moreover, MAFG-AS1 takes its part in the tumorigenesis and progression of various human malignancies by suppressing apoptosis and promoting proliferation, migration, invasion, aerobic glycolysis, ferroptosis, angiogenesis, EMT, and metastasis. Besides, it can predict treatment effectiveness in ER + breast cancer, urothelial bladder carcinoma, and liver cancer by functioning as a trigger of resistance to tamoxifen, sorafenib, and cisplatin. This study systematically presents the functions of MAFG-AS1 in various cancers, as well as the findings of bioinformatics analyses of the MAFG-AS1, which should give clear advice for future research.

Correlation between long non-coding RNA MAFG-AS1 and cancer prognosis: a meta-analysis

Background

MAF transcription factor G antisense RNA 1 (MAFG-AS1), a novel long non-coding RNA discovered recently, was proved to be useful in predicting malignancy prognosis. Nevertheless, its association with cancer prognosis has been inconsistent. Therefore, this meta-analysis aimed to explore the clinicopathological and prognostic significance of MAFG-AS1 in diverse carcinomas.

Methods

Studies focused on MAFG-AS1 expression as a prognostic role in cancers were thoroughly searched in six electronic databases. The value of MAFG-AS1 in malignancies was assessed by hazard ratios (HRs) or odds ratios (ORs). Additionally, the GEPIA database was utilized to further strengthen our conclusion.

Results

A total of 15 studies involving 1187 cases and nine types of cancers were recruited into this meta-analysis. High MAFG-AS1 expression was significantly related to advanced tumor stage (OR = 0.52, 95%CI [0.39, 0.69], P < 0.00001), earlier lymph node metastasis (OR = 3.62, 95%CI [2.19, 5.99], P < 0.00001), worse tumor differentiation (OR = 0.64, 95%CI [0.43, 0.95], P = 0.03), and poor overall survival (HR = 1.94, 95%CI [1.72, 2.19], P < 0.00001). No significant heterogeneity and publication bias was detected across studies. Meanwhile, MAFG-AS1 was significantly elevated in ten kinds of cancers based on the validation of the GEPIA database.

Conclusion

The results of this meta-analysis indicated that high MAFG-AS1 expression is dramatically correlated with unfavorable prognosis in cancers. MAFG-AS1 may be served as a promising biomarker for malignancies.

LncRNA MAFG-AS1 is involved in human cancer progression

Long noncoding RNAs (lncRNAs) refer to a type of non-protein-coding transcript of more than 200 nucleotides. LncRNAs play fundamental roles in disease development and progression, and lncRNAs are dysregulated in many pathophysiological processes. Thus, lncRNAs may have potential value in clinical applications. The lncRNA, MAF BZIP Transcription Factor G (MAFG)-AS1, is dysregulated in several cancer, including breast cancer, lung cancer, liver cancer, bladder cancer, colorectal cancer, gastric cancer, esophagus cancer, prostate cancer, pancreatic cancer, ovarian cancer, and glioma. Altered MAFG-AS1 levels are also associated with diverse clinical characteristics and patient outcomes. Mechanistically, MAFG-AS1 mediates a variety of cellular processes via the regulation of target gene expression. Therefore, the diagnostic, prognostic, and therapeutic aspects of MAFG-AS1 have been widely explored. In this review, we discuss the expression, major roles, and molecular mechanisms of MAFG-AS1, the relationship between MAFG-AS1 and clinical features of diseases, and the clinical applications of MAFG-AS1.

Roles of non-coding RNAs in the metabolism and pathogenesis of bladder cancer

Bladder cancer (BC) is featured as the second most common malignancy of the urinary tract worldwide with few treatments leading to high incidence and mortality. It stayed a virtually intractable disease, and efforts to identify innovative and effective therapies are urgently needed. At present, more and more evidence shows the importance of non-coding RNA (ncRNA) for disease-related study, diagnosis, and treatment of diverse types of malignancies. Recent evidence suggests that dysregulated functions of ncRNAs are closely associated with the pathogenesis of numerous cancers including BC. The detailed mechanisms underlying the dysregulated role of ncRNAs in cancer progression are still not fully understood. This review mainly summarizes recent findings on regulatory mechanisms of the ncRNAs, long non-coding RNAs, microRNAs, and circular RNAs, in cancer progression or suppression and focuses on the predictive values of ncRNAs-related signatures in BC clinical outcomes. A deeper understanding of the ncRNA interactive network could be compelling framework for developing biomarker-guided clinical trials.

Long non-coding RNA MAFG-AS1: A promising therapeutic target for human cancers

Long non-coding RNAs (lncRNAs) are commonly known for their important characters in cancer progression. LncRNA MAFG-antisense 1 (AS1) (MAFG-AS1) has been discovered as a novel oncogenic lncRNA for several years. Accumulating data have demonstrated abnormal overexpression of MAFG-AS1 in various human cancers, including breast, bladder, liver, gastric, and lung. Importantly, through regulating various microRNAs and cell signaling pathways, MAFG-AS1 has been demonstrated to exhibit various biological effects, including proliferation, metastasis, and epithelial-mesenchymal transition (EMT). Meanwhile, abnormal overexpression of MAFG-AS1 is closely linked with histological grade, TNM stage, extensive depth of invasion, poor OS, and lymph node metastasis (LNM). In the present review, the authors summarized the previous studies on the biological properties, molecular mechanisms, and clinicopathological characters of MAFG-AS1 in human cancers. In summary, MAFG-AS1 is a promising prognostic biological marker and potential therapeutic target for cancer treatment.

A review on the roles and molecular mechanisms of MAFG-AS1 in oncogenesis

Long non-coding RNAs (lncRNAs) have more than 200 nucleotides and do not encode proteins. At the same time, they can regulate various biological functions and therefore play an essential role as oncogenes or tumor suppressors in human cancers. MAFG-AS1 is an antisense RNA of MAF BZIP Transcription Factor G (MAFG) located at chromosome 17q25.3 head-to-head with the MAFG encoding gene containing a transcript size of 1895 bp. Accumulating evidence shows that MAFG-AS1 is overexpressed in many cancers, functions as an oncogene, and is significantly associated with poor clinical characteristics and prognosis. In this review, we first discuss the recent literature regarding the role of MAFG-AS1 in different cancers as well as its diagnostic and prognostic values. Then we will provide insights into its biological functions, such as its role in cancer progression, competing endogenous RNA (ceRNA) activity, regulation of EMT, glycolysis, energy metabolism, transcription factors, proteasomal degradation, and signaling pathways.

Recent Clinical Advances on Long Non-Coding RNAs in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a more aggressive type of breast cancer due to its heterogeneity and complex molecular mechanisms. TNBC has a high risk for metastasis, and it is difficult to manage clinical conditions of the patients. Various investigations are being conducted to overcome these challenges using RNA, DNA, and proteins for early diagnosis and treatment. Recently, long non-coding RNAs (lncRNAs) have emerged as a novel target to treat the multistep process of TNBC. LncRNAs regulate epigenetic expression levels, cell proliferation and apoptosis, and tumour invasiveness and metastasis. Thus, lncRNA-based early diagnosis and treatment options could be helpful, especially for patients with severe TNBC. lncRNAs are expressed in a highly specific manner in cells and tissues and are involved in TNBC progression and development. lncRNAs could be used as sensitive and specific targets for diagnosis, treatment, and monitoring of patients with TNBC. Therefore, the exploration of novel diagnostic and prognostic biomarkers is of extreme importance. Here, we discuss the molecular advances on lncRNA regulation of TNBC and lncRNA-based early diagnosis, treatment, and drug resistance.

Low expression of lncRNA APTR promotes gastric cancer progression

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APTR is actively expressed in gastric cancer cells.

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Low expression of APTR is associated with poor clinical characteristics in patients with gastric cancer.

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Silencing APTR promotes gastric cancer proliferation and invasiveness.

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APTR expression is negatively associated with inflammatory signaling in the gastric tumor microenvironment.

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LncRNA APRT is a potential biomarker for gastric cancer patients' diagnosis and prognosis, and could be a potential therapeutic target.

Background

Gastric cancer (GC) is one of the most common cancers worldwide and the majority of GC patients are diagnosed at advanced stages due to the lack of early detection biomarkers. LncRNAs have been shown to play important roles in various diseases and could be predictive biomarkers and therapeutic targets. Our study demonstrated that low expression of lncRNA APTR could promote gastric cancer progression.

Methods

Differentiated expressed lncRNAs were identified through analyzing TCGA paired GC RNA sequencing data. LncRNA APTR's clinical relevance was analyzed using the TCGA dataset and GEO datasets. APTR expression in patient samples was detected through qPCR. The proliferation, colony formation, and migration of GC cells were tested. Bioinformatic analyses were performed to explore APTR-affected signaling pathways in GC.

Results

LncRNA APTR is lower expressed in gastric tumor samples and low expression of APTR predicts a poor diagnosis and outcome in GC patients. Silencing APTR promotes gastric cancer proliferation and invasiveness. APTR expression is negatively correlated with inflammatory signaling in the gastric tumor microenvironment.

Conclusion

Our study showed that low expression of lncRNA APTR in gastric cancer is correlated with tumorigenesis and poor diagnosis and prognosis, which is a potential biomarker for gastric cancer patients' diagnosis and treatment.