KHSRP-bound small nucleolar RNAs associate with promotion of cell invasiveness and metastasis of pancreatic cancer

[High LINC00626 expression promotes esophagogastric junction adenocarcinoma metastasis: the mediating role of the JAK1/STAT3/KHSRP axis]

OBJECTIVE

To investigate the role of JAK1/STAT3/KHSRP axis in mediating the regulatory effect of LINC00626 on progression of esophagogastric junction adenocarcinoma.

METHODS

We collected surgical tumor and adjacent tissue specimens from 64 patients with esophagogastric junction adenocarcinoma and examined the expression levels of LINC00626 and KHSRP. qRT-PCR was used to detect the expressions of LINC00626 and KHSRP in 6 esophageal adenocarcinoma cell lines (OE-19, TE-7, Bic-1, Flo-1, SK-GT-4, and BE-3) and a normal esophageal epithelial cell line (HET-1A). OE-19 and TE-7 cell lines with stable LINC00626 knockdown and FLO-1 and SK-GT-4 cells stably overexpressing LINC00626 were constructed by lentiviral transfection, and the changes in proliferation, migration and invasion of the cells were evaluated using Cell Counting Kit-8 (CCK-8) assay and Transwell migration/invasion assay. The expressions of KHSRP and JAK/STAT pathway proteins in the transfected cells were detected with Western blotting. The effects of LINC006266 knockdown and overexpression on subcutaneous tumor formation and lung metastasis of OE-19 and FLO-1 cell xenografts were tested in nude mice.

RESULTS

The expression levels of LINC00626 and KHSRP were significantly increased in esophagogastric junction adenocarcinoma tissues and in esophageal adenocarcinoma cells. LINC00626 knockdown obviously inhibited the proliferation, migration and invasion of esophageal adenocarcinoma cells in vitro and decreased their tumor formation and lung metastasis abilities in nude mice, while overexpression of LINC00626 produced the opposite effects. In esophageal adenocarcinoma cells, LINC0626 knockdown significantly decreased and LINC00626 overexpression strongly enhanced the phosphorylation of JAK1 and STAT3.

CONCLUSION

High LINC00626 expression promotes esophageal-gastric junction adenocarcinoma metastasis by activating the JAK1/STAT3/KHSRP signal axis.

KSRP improves pancreatic beta cell function and survival

Impaired insulin production and/or secretion by pancreatic beta cells can lead to high blood glucose levels and type 2 diabetes (T2D). Therefore, investigating new proteins involved in beta cell response to stress conditions could be useful in finding new targets for therapeutic approaches. KH-type splicing regulatory protein (KSRP) is a protein usually involved in gene expression due to its role in post-transcriptional regulation. Although there are studies describing the important role of KSRP in tissues closely related to glucose homeostasis, its effect on pancreatic beta cells has not been explored so far. Pancreatic islets from diet-induced obese mice (C57BL/6JUnib) were used to determine KSRP expression and we also performed in vitro experiments exposing INS-1E cells (pancreatic beta cell line) to different stressors (palmitate or cyclopiazonic acid-CPA) to induce cellular dysfunction. Here we show that KSRP expression is reduced in all the beta cell dysfunction models tested. In addition, when manipulated to knock down KSRP, beta cells exhibited increased death and impaired insulin secretion, whereas KSRP overexpression prevented cell death and increased insulin secretion. Taken together, our findings suggest that KSRP could be an important target to protect beta cells from impaired functioning and death.

Long intergenic non-protein coding RNA 115 (Linc00115): A notable oncogene in human malignancies

Long noncoding RNAs (LncRNAs) are RNA transcripts ranging from 200 to 1000 nucleotides that have emerged as critical regulators of gene expression. Growing evidence highlights their involvement in tumor development. In particular, long intergenic non-protein coding RNA115 (Linc00115) has been identified as an oncogene across various human malignancies, with aberrant expression strongly linked to poor clinical outcomes in cancer patients. This review aims to delve into the expression patterns of Linc00115 and elucidate the underlying molecular mechanisms behind its oncogenic properties. Moreover, we discuss the potential utility of Linc00115 as a valuable diagnostic and prognostic biomarker in cancer.

K-Homology Type Splicing Regulatory Protein: Mechanism of Action in Cancer and Immune Disorders

K homology-type splicing regulatory protein (KSRP) is emerging as a key player in cancer biology, and immunology. As a single-strand nucleic acid binding protein it functions in both transcriptional and post-transcriptional regulation, while facilitating multiple stages of RNA metabolism to affect proliferation and control cell fate. However, it must interact with other proteins to determine the fate of its bound substrate. Here we provide an minireview of this important regulatory protein and describe its complex subcellular functions to affect RNA metabolism, stability, miRNA biogenesis and maturation, stress granule function, metastasis, and inflammatory processes.

Large-scale ORF screening based on LC-MS to discover novel lncRNA-encoded peptides responding to ionizing radiation and microgravity

In the human genome, 98% of genes can be transcribed into non-coding RNAs (ncRNAs), among which lncRNAs and their encoded peptides play important roles in regulating various aspects of cellular processes and may serve as crucial factors in modulating the biological effects induced by ionizing radiation and microgravity. Unfortunately, there are few reports in space radiation biology on lncRNA-encoded peptides below 10kD due to limitations in detection techniques. To fill this gap, we integrated a variety of methods based on genomics and peptidomics, and discovered 22 lncRNA-encoded small peptides that are sensitive to space radiation and microgravity, which have never been reported before. We concurrently validated the transmembrane helix, subcellular localization, and biological function of these small peptides using bioinformatics and molecular biology techniques. More importantly, we found that these small peptides function independently of the lncRNAs that encode them. Our findings have uncovered a previously unknown human proteome encoded by 'non-coding' genes in response to space conditions and elucidated their involvement in biological processes, providing valuable strategies for individual protection mechanisms for astronauts who carry out deep space exploration missions in space radiation environments.

Long non-coding RNA SLC7A11 antisense RNA1 promotes oral squamous cell carcinoma progression by regulating ubiquitination of K-homology type splicing regulatory protein

OBJECTIVES

This article aims to elucidate the role of Long non-coding RNA SLC7A11 antisense RNA1 (SLC7A11-AS1) in oral squamous cell carcinoma, which are expected to be useful for the oral squamous cell carcinoma diagnosis and treatment.

DESIGN

SLC7A11-AS1 expression was detected by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) in oral squamous cell carcinoma cell lines. Cellular localization of SLC7A11-AS1C was detected by fluorescence in situ hybridization (FISH) assays and subcellular fractionation assay. Biological functions of SLC7A11-AS1 were explored by 3-(4,5-dimethyl-2-thiazolyl)- 2,5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), wounding healing, and transwell invasion assays in vitro, as well as mice xenograft experiments and metastasis assays in vivo. RNA pull-down, RNA immunoprecipitation, co-immunoprecipitation, ubiquitination assays, and rescue experiments were performed to determine the molecular mechanism of SLC7A11-AS1 in oral squamous cell carcinoma.

RESULTS

SLC7A11-AS1 is overexpressed in oral cancer tissues and cell lines. Functionally, knockdown of SLC7A11-AS1 reduced the proliferation, migration, and invasion of oral squamous cell carcinoma cells in vitro and inhibited tumor growth as well as metastasis in vivo. Mechanistically, SLC7A11-AS1 impeded the interaction between K-homology type splicing regulatory protein (KHSRP) and kelch-like 12 (KLHL12), maintaining the stability of KHSRP by restraining KHSRP degradation through the ubiquitination-proteasome pathway. Furthermore, KHSRP overexpression recovered the malignant behaviors inhibited by SLC7A11-AS1 knockdown in oral cancer cells.

CONCLUSION

SLC7A11-AS1 promoted oral squamous cell carcinoma development by interacting with KHSRP and maintaining KHSRP stability by preventing its degradation via the ubiquitination-proteasome pathway. Thus, SLC7A11-AS1 is a potential therapeutic target for oral cancer.

DDX24 regulates the chemosensitivity of hepatocellular carcinoma to sorafenib via mediating the expression of SNORA18

Sorafenib (SFN) is a multi-kinase inhibitor drug for the treatment of advanced hepatocellular carcinoma (HCC), but its limited efficacy is a major obstacle to the clinical outcomes of patients with HCC. We aimed to explore a novel molecular mechanism underlying the chemosensitivity of HCC to SFN, and to identify a promising therapeutic target for HCC treatment. In this study, bioinformatic analysis revealed that DDX24 was associated with poor survival in HCC cases, and significantly related to the pathways modulating tumor development. DDX24 regulated HCC cell proliferation and migration potentials. Moreover, reduction of DDX24 promoted the sorafenib-mediated inhibition of HCC cell growth and migration, the elevation of sorafenib-induced HCC cell apoptosis. DDX24 overexpression suppressed the inhibitory effect of SFN on cell proliferation and migration and reduced the apoptosis induced by SFN. Further, DDX24, combined with SFN treatment, presented a synergistic enhancement of the sensitivity of SFN to the growth and migration of HCC cells via AKT/ERK and the epithelial-mesenchymal transition (EMT) pathways, and that it modulated apoptosis via the caspase/PARP pathway. Mechanistically, SNORA18 served as a target gene for DDX24, regulating the chemosensitivity of sorafenib-treated HCC cells. Furthermore, SNORA18 knockdown or overexpression could partially reverse the inhibition or elevation of cell viability, colony formation and migration induced by DDX24 in sorafenib-treated HCC cells, respectively. Collectively, our results suggest that DDX24 regulates the chemosensitivity of HCC to SFN by mediating the expression of SNORA18, which may act as an effective therapeutic target for improving SFN efficiency in HCC treatment.

Lycium barbarum polysaccharide modulates gut microbiota to alleviate rheumatoid arthritis in a rat model

Rheumatoid arthritis (RA) seriously impairs the quality of life of sufferers. It has been shown that Lycium barbarum polysaccharide (LBP), a natural active indigestible ingredient with medicinal and edible functions, can effectively relieve RA, however, whether this effect is related to gut microbiota is not known. This study aimed to explore the RA alleviating mechanism of LBP mediated by gut microbiota using a collagen-induced arthritis rat model. The results showed that LBP significantly changed the gut microflora structure accompanied with the RA alleviation. Specifically, a LBP intervention reduced the relative abundance of Lachnospiraceae_NK4A136_group and uncultured_bacterium_f_Ruminococcaceae and significantly increased the abundance of Romboutsia, Lactobacillus, Dubosiella and Faecalibaculum. The mRNA contents of several colonic epithelial genes including Dpep3, Gstm6, Slc27a2, Col11a2, Sycp2, SNORA22, Tnni1, Gpnmb, Mypn and Acsl6, which are potentially associated to RA, were down-regulated due to the DNA hypermethylation, possibly caused by the elevating content of a bacterial metabolite S-adenosyl methionine (SAM). In conclusion, our current study suggests that LBP alleviated RA by reshaping the composition of intestinal microflora which may generate SAM, inducing DNA hypermethylation of RA-related genes in the host intestinal epithelium and subsequently reducing their expression.

The Role of KH-Type Splicing Regulatory Protein (KSRP) for Immune Functions and Tumorigenesis

Post-transcriptional control of gene expression is one important mechanism that enables stringent and rapid modulation of cytokine, chemokines or growth factors expression, all relevant for immune or tumor cell function and communication. The RNA-binding protein KH-type splicing regulatory protein (KSRP) controls the mRNA stability of according genes by initiation of mRNA decay and inhibition of translation, and by enhancing the maturation of microRNAs. Therefore, KSRP plays a pivotal role in immune cell function and tumor progression. In this review, we summarize the current knowledge about KSRP with regard to the regulation of immunologically relevant targets, and the functional role of KSRP on immune responses and tumorigenesis. KSRP is involved in the control of myeloid hematopoiesis. Further, KSRP-mediated mRNA decay of pro-inflammatory factors is necessary to keep immune homeostasis. In case of infection, functional impairment of KSRP is important for the induction of robust immune responses. In this regard, KSRP seems to primarily dampen T helper cell 2 immune responses. In cancer, KSRP has often been associated with tumor growth and metastasis. In summary, aside of initiation of mRNA decay, the KSRP-mediated regulation of microRNA maturation seems to be especially important for its diverse biological functions, which warrants further in-depth examination.

RNA-binding proteins and cancer metastasis

RNA-binding proteins (RBPs) can regulate gene expression through post-transcriptionally influencing all manner of RNA biology, including alternative splicing (AS), polyadenylation, stability, and translation of mRNAs, as well as microRNAs (miRNAs) and circular RNAs (circRNAs) processing. There is accumulating evidence reinforcing the perception that dysregulation or dysfunction of RBPs can lead to various human diseases, including cancers. RBPs influence diverse cancer-associated cellular phenotypes, such as proliferation, apoptosis, senescence, migration, invasion, and angiogenesis, contributing to the initiation and development of tumors, as well as clinical prognosis. Metastasis is the leading cause of cancer-related recurrence and death. Therefore, it is necessary to elucidate the molecular mechanisms behind tumor metastasis. In fact, a growing body of published research has proved that RBPs play pivotal roles in cancer metastasis. In this review, we will summarize the recent advances for helping us understand the role of RBPs in tumor metastasis, and discuss dysfunctions and dysregulations of RBPs affecting metastasis-associated processes including epithelial-mesenchymal transition (EMT), migration, and invasion of cancer cells. Furthermore, we will discuss emerging RBP-based strategy for the treatment of cancer metastasis.

LncRNA LINC01305 promotes cervical cancer progression through KHSRP and exosome-mediated transfer

Cervical cancer (CC) is one of the deadliest female malignancies worldwide. Long non-coding RNAs (lncRNAs) are essential regulators for cancer progression. This study aimed to elucidate the role of lncRNA LINC01305 in the progression of CC. We found where LINC01305 was expressed in CC tissues and its correlation with the survival rate of CC patients. Functional experiments were performed to elucidate the effect of LINC01305 on CC. The results showed that LINC01305 was increased in CC tumor tissues and was correlated with a lower survival rate. The overexpression and knockdown of LINC01305 enhanced and inhibited the progression of CC, respectively. Additionally, the upregulation of LINC01305 promoted tumor growth in xenograft mice. Moreover, the effect of LINC01305 on CC was mediated through interacting with the RNA-binding protein, KHSRP. Furthermore, LINC01305 was mainly distributed in exosomes and was transferred to recipient cells to enhance CC progression. Lastly, LINC01305 may participate in the regulation of the stemness of CC. Taken together, the results suggest that LINC01305 promotes the progression of CC through KHSRP and that LINC01305 is released through exosomes and is involved in the stemness of CC. This study sheds light on the molecular mechanism underlying the progression of CC.

Noncoding RNAs in drug-resistant pancreatic cancer: A review

Pancreatic cancer is the fourth-leading cause of cancer-related deaths and is expected to be the second-leading cause of cancer-related deaths in Europe and the United States by 2030. The high fatality rate of pancreatic cancer is ascribed to untimely diagnosis, early metastasis and limited responses to both chemotherapy and radiotherapy. Although gemcitabine, 5-fluorouracil and some other drugs can profoundly improve patient prognosis, most pancreatic cancer patients eventually develop drug resistance, leading to poor clinical outcomes. The underlying mechanisms of pancreatic cancer drug resistance are complicated and inconclusive. Interestingly, accumulating evidence has demonstrated that different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play a crucial role in pancreatic cancer resistance to chemotherapy reagents. In this paper, we systematically summarize the molecular mechanism underlying the influence of ncRNAs on the generation and development of drug resistance in pancreatic cancer and discuss the potential role of ncRNAs as prognostic markers and new therapeutic targets for pancreatic cancer.