Nuclear Drosha enhances cell invasion via an EGFR-ERK1/2-MMP7 signaling pathway induced by dysregulated miRNA-622/197 and their targets LAMC2 and CD82 in gastric cancer. Cell Death Dis. 2017;8:e2642. [PMID: 28252644 PMCID: PMC5386557 DOI: 10.1038/cddis.2017.5]

Barley polysaccharides inhibit colorectal cancer by two relatively independent pathways

Colorectal cancer is one of the most common types of cancer worldwide that can lead to serious injury and death. Although polysaccharides are widely recognized as having antitumor activity, there has been little research on the role of barley polysaccharides (BP)1 in colorectal cancer. The results of our research suggest that BP (300 mg/kg) had a significant inhibitory effect on colorectal cancer, and this effect was achieved through two pathways. First, BP can directly promote the secretion of protective metabolites like 5-(4-Hydroxyphenyl)-5-phenylimidazolidine-2,4-dione and 2,3-Bis(4-hydroxyphenyl)propionitrile thereby inhibiting the cancer pathways such as ERK, PI3K, WNT, JAK-STAT, Calcium, and Cell cycle cancer pathways to alleviate inflammation. Second, BP also can enrich beneficial intestinal bacteria such as Colidextribacter, Bilophila, and UCG-003 improve the intestinal barrier, promote the production of beneficial metabolites such as 5,8-Epoxy-5,8-dihydro-3-hydroxy-8'-apo-b,y-carotenal and L-Glutamic acid, and thus inhibit cancer pathways such as ERK, PI3K, Nuclear receptor, Cell cycle, Apoptosis and TGF-β. In conclusion, our findings suggest for the first time that BP can alleviate colorectal cancer by two relatively independent pathways: direct action and indirect action via the gut microbiota on both colon tumor cells and microbiota.

The LAMB3-EGFR signaling pathway mediates synergistic Anti-Cancer effects of berberine and emodin in Pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy, primarily due to the intrinsic development of chemoresistance. The most apparent histopathological feature associated with chemoresistance is the alterations in extracellular matrix (ECM) proteins. Natural dietary botanicals such as berberine (BBR) and emodin (EMO) have been shown to possess chemo-preventive potential by regulating ECM in various cancers. Herein, we further investigated the potential synergistic effects of BBR and EMO in enhancing anticancer efficacy by targeting ECM proteins in pancreatic cancer. Genomewide transcriptomic profiling identified that LAMB3 was significantly upregulated in PDAC tissue and highly associated with poor overall survival (OS, hazard ratio [HR], 2.99, 95 % confidence interval [CI], 1.46-6.15; p = 0.003) and progress-free survival (PFS, HR, 2.59; 95 % CI, 1.30-5.18; p = 0.007) in PDAC. A systematic series of functional experiments in BxPC-3 and MIA-PaCa-2 cells revealed that the combination of BBR and EMO exhibited synergistic anti-tumor potential, as demonstrated by cell proliferation, clonogenicity, migration, and invasion assays (p < 0.05-0.001). The combination also altered the expression of key proteins involved in apoptosis, EMT, and EGFR/ERK1,2/AKT signaling. These findings were further supported by patient-derived organoids (PDOs), where the combined treatment resulted in fewer and smaller organoids compared to each compound individually (p < 0.05-0.001). Our results suggest that BBR combined with EMO exerts synergistic anti-cancer effects by modulating the EGFR-signaling pathway through interference with LAMB3 in PDAC.

Biomarkers Identification in the Microenvironment of Oral Squamous Cell Carcinoma: A Systematic Review of Proteomic Studies

An important determinant for oral squamous cell carcinoma (OSCC) onset and outcome is the composition of the tumor microenvironment (TME). Thus, the study of the interactions occurring among cancer cells, immune cells, and cancer-associated fibroblasts within the TME could facilitate the understanding of the mechanisms underlying OSCC development and progression, as well as of its sensitivity or resistance to the therapy. In this context, it must be highlighted that the characterization of TME proteins is enabled by proteomic methodologies, particularly mass spectrometry (MS). Aiming to identify TME protein markers employable for diagnosing and prognosticating OSCC, we have retrieved a total of 119 articles spanning 2001 to 2023, of which 17 have passed the selection process, satisfying all its criteria. We have found a total of 570 proteins detected by MS-based proteomics in the TME of OSCC; among them, 542 are identified by a single study, while 28 are cited by two or more studies. These 28 proteins participate in extracellular matrix remodeling and/or energy metabolism. Here, we propose them as markers that could be used to characterize the TME of OSCC for diagnostic/prognostic purposes. Noteworthy, most of the 28 individuated proteins share one feature: being modulated by the hypoxia that is present in the proliferating OSCC mass.

Single-cell analysis uncovers high-proliferative tumour cell subtypes and their interactions in the microenvironment of gastric cancer

Gastric cancer (GC) remains a prominent malignancy that poses a significant threat to human well-being worldwide. Despite advancements in chemotherapy and immunotherapy, which have effectively augmented patient survival rates, the mortality rate associated with GC remains distressingly high. This can be attributed to the elevated proliferation and invasive nature exhibited by GC. Our current understanding of the drivers behind GC cell proliferation remains limited. Hence, in order to reveal the molecular biological mechanism behind the swift advancement of GC, we employed single-cell RNA-sequencing (scRNA-seq) to characterize the tumour microenvironment in this study. The scRNA-seq data of 27 patients were acquired from the Gene Expression Omnibus database. Differential gene analysis, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis were employed to investigate 38 samples. The copy number variation level exhibited by GC cells was determined using InferCNV. The CytoTRACE, Monocle and Slingshot analysis were used to discern the cellular stemness and developmental trajectory of GC cells. The CellChat package was utilized for the analysis of intercellular communication crosstalk. Moreover, the findings of the data analysis were validated through cellular functional tests conducted on the AGS cell line and SGC-7901 cell line. Finally, this study constructed a risk scoring model to evaluate the differences of different risk scores in clinical characteristics, immune infiltration, immune checkpoints, functional enrichment, tumour mutation burden and drug sensitivity. Within the microenvironment of GC, we identified the presence of 8 cell subsets, encompassing NK_T cells, B_Plasma cells, epithelial cells, myeloid cells, endothelial cells, mast cells, fibroblasts, pericytes. By delving deeper into the characterization of GC cells, we identified 6 specific tumour cell subtypes: C0 PSCA+ tumour cells, C1 CLDN7+ tumour cells, C2 UBE2C+ tumour cells, C3 MUC6+ tumour cells, C4 CHGA+ tumour cells and C5 MUC2+ tumour cells. Notably, the C2 UBE2C+ tumour cells demonstrated a close association with cell mitosis and the cell cycle, exhibiting robust proliferative capabilities. Our findings were fortified through enrichment analysis, pseudotime analysis and cell communication analysis. Meanwhile, knockdown of the transcription factor CREB3, which is highly active in UBE2C+ tumour cells, significantly impedes the proliferation, migration and invasion of GC cells. And the prognostic score model constructed with CREB3-related genes showcased commendable clinical predictive capacity, thus providing valuable guidance for patients' prognosis and clinical treatment decisions. We have identified a highly proliferative cellular subgroup C2 UBE2C+ tumour cells in GC for the first time. The employment of a risk score model, which is based on genes associated with UBE2C expression, exhibits remarkable proficiency in predicting the prognosis of GC patients. In our investigation, we observed that the knockdown of the transcription factor CREB3 led to a marked reduction in cellular proliferation, migration and invasion in GC cell line models. Implementing a stratified treatment approach guided by this model represents a judicious and promising methodology.

LAMC2 regulates the proliferation, invasion, and metastasis of gastric cancer via PI3K/Akt signaling pathway

OBJECTIVES

Gastric cancer (GC) is a prevalent malignant tumor widely distributed globally, exhibiting elevated incidence and fatality rates. The gene LAMC2 encodes the laminin subunit gamma-2 chain and is found specifically in the basement membrane of epithelial cells. Its expression is aberrant in multiple types of malignant tumors. This research elucidated a link between LAMC2 and the clinical characteristics of GC and investigated the potential involvement of LAMC2 in GC proliferation and advancement.

MATERIALS AND METHODS

LAMC2 expressions were detected in GC cell lines and normal gastric epithelial cell lines via qRT-PCR. Silencing and overexpression of the LAMC2 were conducted by lentiviral transfection. A xenograft mouse model was also developed for in vivo analysis. Cell functional assays were conducted to elucidate the involvement of LAMC2 in cell growth, migration, and penetration. Further, immunoblotting was conducted to investigate the impact of LAMC2 on the activation of signal pathways after lentiviral transfection.

RESULTS

In the findings, LAMC2 expression was markedly upregulated in GC cell lines as opposed to normal gastric epithelial cells. In vitro analysis showed that sh-LAMC2 substantially inhibited GC cell growth, migration, and invasion, while oe-LAMC2 displayed a contrasting effect. Xenograft tumor models demonstrated that oe-LAMC2 accelerated tumor growth via high expression of Ki-67. Immunoblotting analysis revealed a substantial decrease in various signaling pathway proteins, PI3K, p-Akt, and Vimentin levels upon LAMC2 knockdown, followed by increased E-cadherin expression. Conversely, its overexpression exhibited contrasting effects. Besides, epithelial-mesenchymal transition (EMT) was accelerated by LAMC2.

CONCLUSION

This study provides evidence indicating that LAMC2, by stimulating signaling pathways, facilitated EMT and stimulated the progression of GC cells in laboratory settings and mouse models. Research also explored that the abnormal LAMC2 expression acts as a biomarker for GC.

Tspan protein family: focusing on the occurrence, progression, and treatment of cancer

The Tetraspanins (Tspan) protein family, also known as the tetraspanin family, contains 33 family members that interact with other protein molecules such as integrins, adhesion molecules, and T cell receptors by forming dimers or heterodimers. The Tspan protein family regulates cell proliferation, cell cycle, invasion, migration, apoptosis, autophagy, tissue differentiation, and immune response. More and more studies have shown that Tspan proteins are involved in tumorigenesis, epithelial-mesenchymal transition, thrombosis, tumor stem cell, and exosome signaling. Some drugs and microRNAs can inhibit Tspan proteins, thus providing new strategies for tumor therapy. An in-depth understanding of the functions and regulatory mechanisms of the Tspan protein family, which can promote or inhibit tumor development, will provide new strategies for targeted interventions in the future.

Cellular senescence is associated with the spatial evolution toward a higher metastatic phenotype in colorectal cancer

In this study, we explore the dynamic process of colorectal cancer progression, emphasizing the evolution toward a more metastatic phenotype. The term "evolution" as used in this study specifically denotes the phenotypic transition toward a higher metastatic potency from well-formed glandular structures to collective invasion, ultimately resulting in the development of cancer cell buddings at the invasive front. Our findings highlight the spatial correlation of this evolution with tumor cell senescence, revealing distinct types of senescent tumor cells (types I and II) that play different roles in the overall cancer progression. Type I senescent tumor cells (p16INK4A+/CXCL12+/LAMC2-/MMP7-) are identified in the collective invasion region, whereas type II senescent tumor cells (p16INK4A+/CXCL12+/LAMC2+/MMP7+), representing the final evolved form, are prominently located in the partial-EMT region. Importantly, type II senescent tumor cells associate with local invasion and lymph node metastasis in colorectal cancer, potentially affecting patient prognosis.

Knockdown of ribosome RNA processing protein 15 suppresses migration of hepatocellular carcinoma through inhibiting PATZ1-associated LAMC2/FAK pathway

BACKGROUND

Ribosomal RNA processing protein 15 (RRP15) has been found to regulate the progression of hepatocellular carcinoma (HCC). Nevertheless, the extent to which it contributes to the spread of HCC cells remains uncertain. Thus, the objective of this research was to assess the biological function of RRP15 in the migration of HCC.

METHODS

The expression of RRP15 in HCC tissue microarray (TMA), tumor tissues and cell lines were determined. In vitro, the effects of RRP15 knockdown on the migration, invasion and adhesion ability of HCC cells were assessed by wound healing assay, transwell and adhesion assay, respectively. The effect of RRP15 knockdown on HCC migration was also evaluated in vivo in a mouse model.

RESULTS

Bioinformatics analysis showed that high expression of RRP15 was significantly associated with low survival rate of HCC. The expression level of RRP15 was strikingly upregulated in HCC tissues and cell lines compared with the corresponding controls, and TMA data also indicated that RRP15 was a pivotal prognostic factor for HCC. RRP15 knockdown in HCC cells reduced epithelial-to-mesenchymal transition (EMT) and inhibited migration in vitro and in vivo, independent of P53 expression. Mechanistically, blockade of RRP15 reduced the protein level of the transcription factor POZ/BTB and AT hook containing zinc finger 1 (PATZ1), resulting in decreased expression of the downstream genes encoding laminin 5 subunits, LAMC2 and LAMB3, eventually suppressing the integrin β4 (ITGB4)/focal adhesion kinase (FAK)/nuclear factor κB kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway.

CONCLUSIONS

RRP15 promotes HCC migration by activating the LAMC2/ITGB4/FAK pathway, providing a new target for future HCC treatment.

Circulating miRNAs and lncRNAs serve as biomarkers for early colorectal cancer diagnosis

BACKGROUND

Colorectal cancer (CRC), the third most prevalent and lethal disease, accounted for approximately 1.9 million new cases and claimed nearly 861,000 lives in 2018. It is imperative to develop a minimally invasive diagnostic technique for early identification of CRC. This would facilitate the selection of patient populations most suitable for clinical trials, monitoring disease progression, assessing treatment effectiveness, and enhancing overall patient care. Utilizing blood as a biomarker source is advantageous due to its minimal discomfort for patients, enabling better integration into clinical and follow-up trials. Recent findings indicate that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are detectable in the blood of cancer patients, proving crucial in diagnosing various malignancies.

METHODS

In this case-control study, we collected plasma samples from 30 patients diagnosed with colorectal cancer (CRC) and 30 healthy volunteers. Following RNA extraction, we measured the expression levels of specific biomolecules, including miR-410, miR-211, miR-139, miR-197, lncRNA UICLM, lncRNA FEZF1-AS1, miR-129, lncRNA CCAT1, lncRNA BBOX1-AS1, and lncRNA LINC00698, using real-time quantitative polymerase chain reaction (RT-qPCR). The obtained data underwent analysis using the Mann-Whitney test for non-parametric data and the T-test for parametric data.

RESULTS

The level of miR-410, miR-211, miR-139, miR-197, lncRNA UICLM, lncRNA FEZF1-AS1 were significantly higher in patients with CRC than healthy controls (p < .05). Meanwhile, the level of miR-129, lncRNA CCAT1, lncRNA BBOX1-AS1, and lncRNA LINC00698 were higher in healthy controls than in CRC patients (p < .05).

CONCLUSION

MicroRNA (miRNA) and long noncoding RNAs (lncRNAs) have recently emerged as detectable entities in the blood of cancer patients, playing crucial roles in diagnosing various malignancies. However, their specific relevance in the diagnosis of colorectal cancer (CRC) remains underexplored. This study aimed to investigate miRNA and lncRNA profiles in the plasma fraction of human blood to discern significant differences in content and expression levels between CRC patients and healthy individuals. Our cohort comprised 30 CRC patients and 30 healthy controls, with no statistically significant differences (p < 0.05) in age or gender observed between the two groups. Noteworthy is the uniqueness of our study, as we identified a panel of three significant microRNAs and one significant lncRNA, providing a more reliable prediction compared to existing molecular markers in diagnosing CRC. The four genes examined, including miR-211, miR-129, miR-197, and lncRNA UICLM, demonstrated impeccable results in terms of sensitivity and specificity, suggesting their potential candidacy for inclusion in diagnostic panels. Further validation in a larger statistical population is recommended to confirm the robustness of these genes as promising markers for colorectal cancer diagnosis.

The role of Tetraspanins in digestive system tumor development: update and emerging evidence

Digestive system malignancies, including cancers of the esophagus, pancreas, stomach, liver, and colorectum, are the leading causes of cancer-related deaths worldwide due to their high morbidity and poor prognosis. The lack of effective early diagnosis methods is a significant factor contributing to the poor prognosis for these malignancies. Tetraspanins (Tspans) are a superfamily of 4-transmembrane proteins (TM4SF), classified as low-molecular-weight glycoproteins, with 33 Tspan family members identified in humans to date. They interact with other membrane proteins or TM4SF members to form a functional platform on the cytoplasmic membrane called Tspan-enriched microdomain and serve multiple functions including cell adhesion, migration, propagation and signal transduction. In this review, we summarize the various roles of Tspans in the progression of digestive system tumors and the underlying molecular mechanisms in recent years. Generally, the expression of CD9, CD151, Tspan1, Tspan5, Tspan8, Tspan12, Tspan15, and Tspan31 are upregulated, facilitating the migration and invasion of digestive system cancer cells. Conversely, Tspan7, CD82, CD63, Tspan7, and Tspan9 are downregulated, suppressing digestive system tumor cell metastasis. Furthermore, the connection between Tspans and the metastasis of malignant bone tumors is reviewed. We also summarize the potential role of Tspans as novel immunotherapy targets and as an approach to overcome drug resistance. Finally, we discuss the potential clinical value and therapeutic targets of Tspans in the treatments of digestive system malignancies and provide some guidance for future research.

microRNA-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation

BACKGROUND

Epigenetic alterations contribute greatly to the development and progression of colorectal cancer, and effect of aberrant miR-622 expression is still controversial. This study aimed to discover miR-622 regulation in CRC proliferation.

METHODS

miR-622 expression and prognosis were analyzed in clinical CRC samples from Nanfang Hospital. miR-622 regulation on cell cycle and tumor proliferation was discovered, and FOLR2 was screened as functional target of miR-622 using bioinformatics analysis, which was validated via dual luciferase assay and gain-of-function and loss-of-function experiments both in vitro and in vivo.

RESULTS

miR-622 overexpression in CRC indicated unfavorable prognosis and it regulated cell cycle to promote tumor growth both in vitro and in vivo. FOLR2 is a specific, functional target of miR-622, which negatively correlates with signature genes in cell cycle process to promote CRC proliferation.

CONCLUSIONS

miR-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation, proposing a novel mechanism and treatment target in CRC epigenetic regulation of miR-622.

LAMC2 mitigates ER stress by enhancing ER-mitochondria interaction via binding to MYH9 and MYH10

Highly proliferative and metastatic tumors are constantly exposed to both intrinsic and extrinsic factors that induce adaptation to stressful conditions. Chronic adaptation to endoplasmic reticulum (ER) ER stress is common to many different types of cancers, and poses a major challenge for acquired drug resistance. Here we report that LAMC2, an extracellular matrix protein upregulated in many types of cancers, is localized in the ER of lung, breast, and liver cancer cells. Under tunicamycin-induced ER stress, protein level of LAMC2 is upregulated. Transfection of cancer cells with LAMC2 resulted in the attenuation of ER stress phenotype, accompanied by elevation in mitochondrial membrane potential as well as reduction in reactive oxygen species (ROS) levels and apoptosis. In addition, LAMC2 forms protein complexes with MYH9 and MYH10 to promote mitochondrial aggregation and increased ER-mitochondria interaction at the perinuclear region. Moreover, overexpression of LAMC2 counteracts the effects of ER stress and promotes tumor growth in vivo. Taken together, our results revealed that in complex with MYH9 and MYH10, LAMC2 is essential for promoting ER-mitochondria interaction to alleviate ER stress and allow cancer cells to adapt and proliferate under stressful conditions. This study provides new insights and highlights the promising potential of LAMC2 as a therapeutic target for cancer treatment.

LAMC2 promotes EGFR cell membrane localization and acts as a novel biomarker for tyrosine kinase inhibitors (TKIs) sensitivity in lung cancer

The epidermal growth factor receptor (EGFR) is one of the first and most prominent driver genes known to promote malignant lung cancer. Investigating regulatory mechanisms beyond ligand-receptor binding, phosphorylation, and receptor kinase activation as means of EGFR signaling activation is important for improving EGFR-targeted therapy. Here, we report that Laminin-5γ-2 (LAMC2) retained high oncogenic capacity in lung cancer, silencing LAMC2 inhibited EGFR-induced cell proliferation and tumor growth in vivo. Deletion mutation experiments showed that both the EGF-Lam and LamB regions of LAMC2 are necessary for EGFR receptor binding, and that LAMC2 and EGFR were found to co-localize at the endoplasmic reticulum (ER) membrane. In addition, LAMC2 overexpression enhanced EGFR membrane deposition and promoted EGFR transport from the ER. Moreover, LAMC2 was necessary for preventing EGFR protein degradation via ubiquitination. Lastly, our study showed that high LAMC2 expression is positively associated with response to gefitinib (EGFR tyrosine kinase inhibitor) treatment. Overall, our study revealed a new regulatory mechanism of LAMC2 in promoting EGFR protein expression and stability by facilitating ER transport and preventing protein degradation via ubiquitination. Moreover, LAMC2 may serve as a stratifying biomarker for patients suitable for EGFR-TKI treatment.

SBF2-AS1 and TreRNA: novel lncRNA players in triple-negative breast cancer pathogenesis

BACKGROUND

Compared to other breast cancer subtypes, triple-negative breast cancer (TNBC) has always been challenging for clinicians due to its aggressive behavior and lack of a specific treatment. There is a confirmed association between invasive features of tumors and increased epithelial-mesenchymal transition (EMT) process, which is consistent with a higher rate of EMT in TNBC.

METHODS AND RESULTS

We investigated the expression of EMT-related genes, SNAI1 and MMP7, and EMT-related lncRNAs, treRNA and SBF2-AS1, in 50 TNBC tumors and 50 non-TNBC tumors to reveal more regulators and effectors involved in TNBC malignancy. In the present study, we showed the overexpression of all the studied genes and lncRNAs in TNBC tumors compared to non-TNBC samples. Moreover, a significant association was observed between MMP7 and treRNA expression levels and larger tumor size. A positive correlation between SNAI1 and lncRNA treRNA expression levels was also detected.

CONCLUSIONS

Due to the differential expression and the potential diagnostic power of the studied genes, SBF2-AS1 and treRNA can be proposed as new probable biomarkers and therapeutic targets in TNBC.

The RGG motif proteins: Interactions, functions, and regulations

Proteins with motifs rich in arginines and glycines were discovered decades ago and are functionally involved in a staggering range of essential processes in the cell. Versatile, specific, yet adaptable molecular interactions enabled by the unique combination of arginine and glycine, combined with multiplicity of molecular recognition conferred by repeated di-, tri-, and multiple peptide motifs, allow RGG motif proteins to interact with a broad range of proteins and nucleic acids. Furthermore, posttranslational modifications at the arginines in the motif extend the RGG protein's capacity for a fine-tuned regulation. In this review, we focus on the biochemical properties of the RGG motif, its molecular interactions with RNAs and proteins, and roles of the posttranslational modification in modulating their interactions. We discuss current knowledge of the RGG motif proteins involved in mRNA transport and translation, highlight our merging understanding of their molecular functions in translational regulation and summarize areas of research in the future critical in understanding this important family of proteins. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Mechanisms.

The Drosha-Independent MicroRNA6778-5p/GSK3β Axis Mediates the Proliferation of Gastric Cancer Cells

Background

Gastric cancer (GC) is a primary cause of cancer death around the world. Previous studies have found that Drosha plays a significant role in the development of tumor cells. Soon after, we unexpectedly found that the expression of microRNA6778-5p (miR6778-5p) is unconventionally high in the gastric cancer cells low-expressing Drosha. So, we designed the Drosha interference sequence and recombined it into a lentiviral vector to construct Drosha knockdown lentivirus and transfected the Drosha knockdown lentivirus into gastric cancer cells to establish Drosha knockdown gastric cancer cell lines. We aimed to explore the effect of microRNA6778-5p on the proliferation of gastric cancer cells with Drosha knockdown and its intrinsic mechanism.

Methods

We designed the Drosha interference sequence and recombined it into a lentiviral vector to construct Drosha knockdown lentivirus and transfected the Drosha knockdown lentivirus into gastric cancer cells to establish Drosha knockdown gastric cancer cell lines. After transfecting miR6778-5p mimics and inhibitor into gastric cancer cell lines with Drosha knockdown, the expression levels of miR6778-5p mimics in Drosha low-expressing gastric cancer cells increased, while miR6778-5p inhibitor decreased the expression levels of miR6778-5p. The Cell Counting Kit-8 (CCK-8) experiment was used to detect the proliferation ability of gastric cancer cells after overexpression or knockdown of miR6778-5p and bioinformatics predicted the relationship between miR6778-5p and glycogen synthase kinase-3β (GSK3β).

Results

After infection with the Drosha knockdown lentivirus, Drosha's mRNA and protein levels were significantly downregulated in gastric cancer cells. The expression levels of miR6778-5p mimics in Drosha low-expressing gastric cancer cells increased, while miR6778-5p inhibitor decreased the expression levels of miR6778-5p. Overexpression of miR6778-5p significantly enhanced the proliferation ability of Drosha low-expression gastric cancer cells; on the contrary, knocking down miR6778-5p weakened the proliferation ability of Drosha low-expression gastric cancer cells. Bioinformatics predicted that miR6778-5p targeted glycogen synthase kinase-3β (GSK3β) and the mRNA and protein levels of GSK3β decreased significantly after overexpression of miR6778-5p.

Conclusion

miR6778-5p promotes the proliferation of Drosha low-expressing gastric cancer cells by targeting GSK3β.

Alcohol promotes epithelial mesenchymal transformation-mediated premetastatic niche formation of colorectal cancer by activating interaction between laminin-γ2 and integrin-β1

BACKGROUND

Colorectal cancer (CRC) is a common malignant tumor. Alcohol consumption is positively correlated with CRC malignant metastasis; however, the mechanism is unclear. The interaction between laminin-γ2 (LAMC2) and integrin-β1 (ITGB1) plays a role in premetastatic niche signaling, which may induce epithelial mesenchymal transformation (EMT) and lead to metastasis.

AIM

To investigate the effects of alcohol on CRC metastasis from the molecular mechanism of the premetastatic niche.

METHODS

The interaction between LAMC2 and ITGB1 was measured by Duolink assay, and the expression levels of LAMC2, ITGB1 and focal adhesion kinase (FAK), snail, fibronectin, N-cadherin and special AT-rich sequence binding protein 1 (SATB1) were measured by quantitative real-time polymerase chain reaction, immunohistochemistry and western blotting. Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and IL-6 levels were measured via enzyme-linked immunosorbent assay, histopathological assessment via hematoxylin eosin staining, and determination of aberrant crypt foci via methylene blue.

RESULTS

The lymph node metastasis rate was higher in the alcohol group than non-alcohol group. There was a significant increase in interaction signals between LAMC2 and ITGB1, and an increase in phosphorylate-FAK/FAK, snail, fibronectin, N-cadherin and SATB1, whereas E-cadherin was reduced in the alcohol group compared to the non-alcohol group in both animal and clinical samples. Serum IL-1β, TNF-α and IL-6 were higher in alcohol group than in non-alcohol group. Alcohol may promote CRC metastasis by influencing the molecular mechanism of the premetastatic niche.

CONCLUSION

Our study suggests that alcohol promotes EMT-mediated premetastatic niche formation of CRC by activating the early interaction between LAMC2 and ITGB1 and lead to CRC metastasis.

The Role of ECM Remodeling, EMT, and Adhesion Molecules in Cancerous Neural Invasion: Changing Perspectives

Perineural invasion (PNI) refers to the cancerous invasion of nerves. It provides an alternative route for metastatic invasion and can exist independently in the absence of lymphatic or vascular invasion. It is a prominent characteristic of specific aggressive malignancies where it correlates with poor prognosis. The clinical significance of PNI is widely recognized despite a lack of understanding of the molecular mechanisms underlying its pathogenesis. The interaction between the nerve and the cancer cells is the most pivotal PNI step which is mediated by the activation or inhibition of multiple signaling pathways that include chemokines, interleukins, nerve growth factors, and matrix metalloproteinases, to name a few. The nerve-cancer cell interaction brings about specific changes in the perineural niche, which not only affects the regular nerve functions, but also enhances the migratory, invasive, and adherent properties of the tumor cells. This review aims to elucidate the vital role of adhesion molecules, extracellular matrix, and epithelial-mesenchymal proteins that promote PNI, which may serve as therapeutic targets in the future.

Does miR-197 Represent a Valid Prognostic Biomarker in Head and Neck Squamous Cell Carcinoma (HNSCC)? A Systematic Review and Trial Sequential Analysis

(1) Background: Between tumors of the head and neck region, the squamous cell variant (HNSCC) is the most common and represents one of the main neoplasms affecting humans. At the base of carcinogenesis processes, there are genetic alterations whose regulation can be influenced by changes in the expression of microRNA (miR). Consequently, despite recent studies indicating miR-197 as a potential prognostic biomarker of survival for many varieties of cancer, there are currently no systematic reviews and trial sequential/bioinformatics/meta-analysis regarding the role of miR-197 in HNSCC. Our hypothesis was that with the existing literature, it is possible to clarify whether the different expressions of miR-197 in neoplastic tissues can represent a prognostic biomarker of survival in head and neck tumors. (2) Methods: The systematic review was reported following the indications of PRISMA and by consulting six electronic databases (including one register). Moreover, this review was carried out using the Kaplan–Meier plotter database portal, and hazard ratio (HR) data were extracted. Finally, a trial sequential analysis (TSA) was conducted to test the robustness of the proposed meta-analysis. (3) Results: This search identified 1119 articles and outcomes of the meta-analysis, reporting an aggregate HR for overall survival (OS) between the highest and lowest miR-197 expression of 1.01, 95% CI: [1.00, 1.02]. (4) Conclusions: We can state that, from the literature data included in the present meta-analysis, and from the TSA and bioinformatics analysis data, miR-197 does not currently represent a valid prognostic biomarker for HNSCC, although the data provided by the Kaplan–Meier plotter suggest that miR-197 can serve as a putative biomarker in short-term (5 years) survival.

KAI1/CD82 gene and autotaxin-lysophosphatidic acid axis in gastrointestinal cancers

The KAI1/CD82 gene inhibits the metastasis of most tumors and is remarkably correlated with tumor invasion and prognosis. Cell metabolism dysregulation is an important cause of tumor occurrence, development, and metastasis. As one of the important characteristics of tumors, cell metabolism dysregulation is attracting increasing research attention. Phospholipids are an indispensable substance in the metabolism in various tumor cells. Phospholipid metabolites have become important cell signaling molecules. The pathological role of lysophosphatidic acid (LPA) in tumors was identified in the early 1990s. Currently, LPA inhibitors have entered clinical trials but are not yet used in clinical treatment. Autotaxin (ATX) has lysophospholipase D (lysoPLD) activity and can regulate LPA levels in vivo. The LPA receptor family and ATX/lysoPLD are abnormally expressed in various gastrointestinal tumors. According to our recent pre-experimental results, KAI1/CD82 might inhibit the migration and metastasis of cancer cells by regulating the ATX-LPA axis. However, no relevant research has been reported. Clarifying the mechanism of ATX-LPA in the inhibition of cancer metastasis by KAI1/CD82 will provide an important theoretical basis for targeted cancer therapy. In this paper, the molecular compositions of the KAI1/CD82 gene and the ATX-LPA axis, their physiological functions in tumors, and their roles in gastrointestinal cancers and target therapy are reviewed.

Proteomic profiling of plasma exosomes reveals CD82 involvement in the development of esophageal squamous cell carcinoma

The Xinjiang Uygur autonomous region has a high incidence of esophageal cancer. For the early diagnosis of patients with esophageal squamous cell carcinoma (ESCC), exosomes were isolated and quantified by liquid chromatography tandem mass spectrometry ((LC-MS/MS) with data independent acquisition (DIA) from the peripheral blood of patients with benign esophageal disease (BED), esophageal intraepithelial neoplasia (EIN) and ESCC. A total of 1117 proteins were identified in the above 9 samples. The proteomic results showed that the quantity of CD82 in exosomes of EIN was significantly higher than that in patients with BED and ESCC. Meanwhile, our ELISA test verified our proteomic results. In addition, the immunohistochemical results showed high CD82 expression in adjacent normal tissues and low expression in ESCC tissues. CD82 expression in ESCC tissues was negatively correlated with tumor stage and the expression of PKM2, and the high expression of CD82 combined with low expression of PKM2 in ESCC tissues suggested a good prognosis. To further clarify the tumor suppressive mechanism of CD82, the TIMER and TISDB databases were analyzed, and CD82 expression in tumor tissues was found to be related to the infiltration of immune cells. CD82 in exosomes is involved in the development of ESCC. SIGNIFICANCE: Xinjiang is a high incidence area of ESCC. When diagnosed in the middle and late stages of the disease, the prognosis of patients is poor. Exosomes provide the possibility of relatively noninvasive and early detection of esophageal carcinogenesis. To the best of our knowledge, this was the first study using the DIA technique to analyze the exosomal proteins of patients with different stages of ESCC. The proteins identified in the exosomes in these three groups could provide insights for understanding how exosomes promote the occurrence of ESCC, the antitumour mechanism of humans and the early diagnosis of ESCC.

Celecoxib Reverse Invasion and Metastasis of Gastric Cancer through Lnc_AC006548.28-miR-223-LAMC2 Pathway

Celecoxib, a specific cyclooxygenase-2 (COX-2) inhibitor, is a traditional nonsteroidal antipyretic analgesic and anti-inflammatory drug commonly used in clinic, which has inhibitory effect on colorectal cancer, gastric cancer, and other malignant tumors. This study showed that Celecoxib could significantly reverse the invasion and metastasis of gastric cancer and improved the pathological changes due to GC. We collected the clinical specimens to analyze the correlation between the expression of Lnc_AC006548.28, miR-223, and LAMC2. In the mouse model, Celecoxib can slowdown the growth of GC tumor and the occurrence of this effect may depend on Lnc_AC006548.28-miR-223-LAMC2 pathway, in vitro transfection, RT-PCR, western blot, CCK8, small chamber assay, flow cytometry, and immunohistochemistry to retest the protective effect of celecoxib. Our results showed that Celecoxib could reverse invasion and metastasis of gastric cancer through Lnc_AC006548.28-miR-223-LAMC2 pathway.

SPC25 promotes hepatocellular carcinoma metastasis via activating the FAK/PI3K/AKT signaling pathway through ITGB4

Hepatocellular carcinoma (HCC) is a malignant tumor with a high metastatic rate. Recent studies have shown that the mitosis-associated spindle-assembly checkpoint regulatory protein spindle pole body component 25 homolog (SPC25) promotes HCC progression, although the underlying mechanism has yet to be fully elucidated. The aim of the present study was to investigate the mechanism through which SPC25 may promote HCC progression in greater detail. First, the expression of SPC25 was analyzed in publicly available databases to explore the association between SPC25 and HCC metastasis. Western blotting was subsequently performed to examine the level of SPC25 expression in different HCC cell lines. SPC25 was then silenced in HCCLM3 and Huh7 cells, and the effects of SPC25 silencing were investigated using cell proliferation, wound-healing, Transwell migration assays and an in vivo mouse model. Finally, the mechanism of SPC25 action with respect to the promotion of HCC metastasis was explored using microarray analysis and rescue experiments. The results obtained demonstrated that SPC25 is highly expressed in HCC, and this high level of expression is associated with poor prognosis and metastasis. Moreover, SPC25 silencing led to a marked inhibition of the invasion and migration of HCC cells both in vitro and in vivo. The gene-expression profiling and mechanistic experiments suggest that SPC25 preferentially influences the expression of genes associated with extracellular matrix (ECM)-integrin interactions, including integrin subunit β4 (ITGB4), an upstream element of the integrin pathway. ITGB4 upregulation partly reversed the decline in cell invasion and migration capacities that resulted from SPC25 silencing. Furthermore, deleting both SPC25 and ITGB4 caused a decrease in the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3-kinase (PI3K) and AKT, which are downstream elements of the integrin pathway. Taken together, the results of the present study demonstrated the important role of SPC25 as a prognostic indicator and as a promoter of metastasis in HCC, and the underlying mechanism of its action has been partially elucidated, suggesting that SPC25 could be used as a biomarker and as a target for therapeutic intervention in the treatment of HCC.

CD82 palmitoylation site mutations at Cys5+Cys74 affect EGFR internalization and metabolism through recycling pathway

Tetraspanin CD82 often participates in regulating the function of epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (c-Met). Palmitoylation is a post-translational modification that contributes to tetraspanin web formation and affects tetraspanin-dependent cell signaling. However, the molecular mechanisms by which CD82 palmitoylation affects the localization and stability of EGFR and c-Met have not yet been elucidated. This study focuses on the expression and distribution of EGFR and c-Met in breast cancer as well as the related metabolic pathways and molecular mechanisms associated with different CD82 palmitoylation site mutations. The results show that CD82 with a palmitoylation mutation at Cys5+Cys74 can promote the internalization of EGFR. EGFR is internalized and strengthened by direct binding to CD82 with the tubulin assistance and located at the recycling endosome. After studying the recycling pathway marker proteins Rab11a and FIP2, we found that formation of the EGFR/CD82/Rab11a/FIP2 complex promotes the internalization and metabolism of EGFR through the recycling pathway and results in the re-expression of EGFR and CD82 on the cell membrane.

Extracellular vesicle microRNAs in celiac disease patients under a gluten-free diet, and in lactose intolerant individuals

BACKGROUND

Celiac disease (CD) is an autoimmune disorder triggered by an abnormal immunological response to gluten ingestion and is associated with deregulated expression of cellular microRNAs (miRNAs) of the gut mucosa. It is frequently misdiagnosed as lactose intolerance (LI) due to symptom resemblance. Microvilli loss may be counteracted by a rigorous gluten-free diet (GFD).

AIMS

To identify altered extracellular vesicle miRNAs from plasma among CD patients on GFD (n=34), lactose intolerant individuals on restrictive diet (n=14) and controls (n=23), and to predict biological pathways in which these altered miRNAs may play a part.

METHODS

Five different small RNA samples of each group were pooled twice and then screened by new-generation sequencing. Four miRNAs were selected to be quantified by RT-qPCR in the entire sample.

RESULTS

The levels of four miRNAs - miR-99b-3p, miR-197-3p, miR-223-3p, and miR-374b-5p - differed between CD patients and controls (P<0.05). Apart from miR-223-3p, all these miRNAs tended to have altered levels also between LI and controls (P<0.10). The results for miR-99b-3p and miR-197-3p between CD and controls were confirmed by RT-qPCR, which also indicated different levels of miR-99b-3p and miR-374b-5p between CD-associated LI and LI (P<0.05).

CONCLUSIONS

These miRNAs may have targets that affect cell death, cell communication, adhesion, and inflammation modulation pathways. Hence, altered miRNA levels could be associated with CD-related aspects and gut mucosa recovery.

A drug-biomarker interaction model to predict the key targets of Scutellaria barbata D. Don in adverse-risk acute myeloid leukaemia

A poor prognosis, relapse and resistance are burning issues during adverse-risk acute myeloid leukaemia (AML) treatment. As a natural medicine, Scutellaria barbata D. Don (SBD) has shown impressive antitumour activity in various cancers. Thus, SBD may become a potential drug in adverse-risk AML treatment. This study aimed to screen the key targets of SBD in adverse-risk AML using the drug-biomarker interaction model through bioinformatics and network pharmacology methods. First, the adverse-risk AML-related critical biomarkers and targets of SBD active ingredient were obtained from The Cancer Genome Atlas database and several pharmacophore matching databases. Next, the protein-protein interaction network was constructed, and topological analysis and pathway enrichment were used to screen key targets and main pathways of intervention of SBD in adverse-risk AML. Finally, molecular docking was implemented for key target verification. The results suggest that luteolin and quercetin are the main active components of SBD against adverse-risk AML, and affected drug resistance, apoptosis, immune regulation and angiogenesis through the core targets AKT1, MAPK1, IL6, EGFR, SRC, VEGFA and TP53. We hope the proposed drug-biomarker interaction model provides an effective strategy for the research and development of antitumour drugs.

Screening and Identification of Key Biomarkers of Gastric Cancer: Three Genes Jointly Predict Gastric Cancer

Background

Gastric cancer (GC) is one of the most common cancers all over the world, causing high mortality. Gastric cancer screening is one of the effective strategies used to reduce mortality. We expect that good biomarkers can be discovered to diagnose and treat gastric cancer as early as possible.

Methods

We download four gene expression profiling datasets of gastric cancer (GSE118916, GSE54129, GSE103236, GSE112369), which were obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between gastric cancer and adjacent normal tissues were detected to explore biomarkers that may play an important role in gastric cancer. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of overlap genes were conducted by the Metascape online database; the protein-protein interaction (PPI) network was constructed by the STRING online database, and we screened the hub genes of the PPI network using the Cytoscape software. The survival curve analysis was conducted by km-plotter and the stage plots of hub genes were created by the GEPIA online database. PCR, WB, and immunohistochemistry were used to verify the expression of hub genes. A neural network model was established to quantify the predictors of gastric cancer.

Results

The relative expression level of cadherin-3 (CDH3), lymphoid enhancer-binding factor 1 (LEF1), and matrix metallopeptidase 7 (MMP7) were significantly higher in gastric samples, compared with the normal groups (p<0.05). Receiver operator characteristic (ROC) curves were constructed to determine the effect of the three genes’ expression on gastric cancer, and the AUC was used to determine the degree of confidence: CDH3 (AUC = 0.800, P<0.05, 95% CI =0.857-0.895), LEF1 (AUC=0.620, P<0.05, 95%CI=0.632-0.714), and MMP7 (AUC=0.914, P<0.05, 95%CI=0.714-0.947). The high-risk warning indicator of gastric cancer contained 8<CDH3<15 and 10<expression of LEF1<16.

Conclusions

CDH3, LEF1, and MMP7 can be used as candidate biomarkers to construct a neural network model from hub genes, which may be helpful for the early diagnosis of gastric cancer.

Targeting CD82/KAI1 for Precision Therapeutics in Surmounting Metastatic Potential in Breast Cancer

Metastasis is the main cause of mortality in breast cancer patients. There is an unmet need to develop therapies that can impede metastatic spread. Precision oncology has shown great promise for the treatment of cancers, as the therapeutic approach is tailored to a specific group of patients who are likely to benefit from the treatment, rather than the traditional approach of "one size fits all". CD82, also known as KAI1, a glycoprotein belonging to the tetraspanin family and an established metastasis suppressor, could potentially be exploited to hinder metastases in breast cancer. This review explores the prospect of targeting CD82 as an innovative therapeutic approach in precision medicine for breast cancer patients, with the goal of preventing cancer progression and metastasis. Such an approach would entail the selection of a subset of breast cancer patients with low levels of CD82, and instituting an appropriate treatment scheme tailored towards restoring the levels of CD82 in this group of patients. Proposed precision treatment regimens include current modalities of treating breast cancer, in combination with either clinically approved drugs that could restore the levels of CD82, CD82 peptide mimics or non-coding RNA-based therapeutics.

Mirtronic miR-4646-5p promotes gastric cancer metastasis by regulating ABHD16A and metabolite lysophosphatidylserines

The aberrant classical miRNAs are considered to play significant roles in tumor progression. However, it remains unclear for nonclassical miRNAs, a set of Drosha-independent miRNAs in the process of various biology. Here, we reveal that a nonclassical miR-4646-5p plays a pivotal role in gastric cancer (GC) metastasis. MiR-4646-5p, one of Drosha-independent mirtronic miRNA, is aberrant up-regulated in Drosha-low expressed GC and Drosha-knockdown gastric cancer cells. Mirtronic miR-4646-5p is a specific transcription splicing product of intron 3 of the host gene Abhd16a with the aid of SRSF2. The enhanced miR-4646-5p can stabilize HIF1A by targeting PHD3 to positive feedback regulate Abhd16a and miR-4646-5p itself expressions. ABHD16A, as an emerging phosphatidylserine-specific lipase, involves in lipid metabolism leading to lysophosphatidylserines (lyso-PSs) accumulation, which stimulates RhoA and downstream LIMK/cofilin cascade activity through GPR34/Gi subunit, thus causes metastasis of gastric cancer. In addition, miR-4646-5p/PHD3/HIF1A signaling can also up-regulate RhoA expression and synergistically promote gastric cancer cell invasion and metastasis. Our study provides new insights of nonclassical mirtronic miRNA on tumor progress and may serve as a new diagnostic biomarker for gastric cancer. MiR-4646-5p and its host gene Abhd16a mediated abnormal lipid metabolism may be a new target for clinical treatment of gastric cancer.

Role of Metastasis Suppressor KAI1/CD82 in Different Cancers

Metastasis is one of the characteristics of malignant tumors and the main cause of death worldwide. The process of metastasis is mainly affected by tumor metastasis genes, tumor metastasis suppressor genes, tumor microenvironment, extracellular matrix degradation, and other factors. Thus, it is essential to elucidate the mechanism of metastasis and find the therapeutic targets in order to prevent the development of malignant tumors. KAI1/CD82, a member of tetraspanin superfamily of glycoproteins, has been reported as a tumor metastasis suppressor gene in various types of cancers without affecting the tumor formation. Many studies have demonstrated that low expression of KAI1/CD82 might lead to poor prognosis due to its interactions with other tetraspanins and integrins, resulting in the regulation of cell motility and invasion, cell-cell adhesion, and apoptosis. Considering its pathological and physiological significance, KAI1/CD82 could be a potential strategy for clinical predicting and preventing tumor progression and metastasis. The present review aims to discuss the role of KAI1/CD82 in metastasis for different cancers and examine its prospects as a metastasis biomarker and a therapeutic target.

A novel strategy to identify candidate diagnostic and prognostic biomarkers for gastric cancer

Background

Gastric cancer (GC) is one of the most common cancer worldwide. It is essential to identify non-invasive diagnostic and prognostic biomarkers of GC. The aim of the present study was to screen candidate biomarkers associated with the pathogenesis and prognosis of GC by a novel strategy.

Methods

The expression level of gene higher in cancer than in adjacent non-cancer tissue was defined as “positive”, and the top 5% genes with “positive rate” were filtered out as candidate diagnostic biomarkers in three Gene Expression Omnibus (GEO) datasets. Further, a prognostic risk model was constructed by multivariate Cox regression analysis in GEO dataset and validated in The Cancer Genome Atlas (TCGA). The expression level of candidate biomarkers was determined in serum and serum-derived exosomes of GC patients. Moreover, the effect of biomarkers in exosomes on migration of GC cells was analyzed by transwell assay.

Results

Ten candidate biomarkers (AGT, SERPINH1, WNT2, LIPG, PLAU, COL1A1, MMP7, MXRA5, CXCL1 and COL11A1) were identified with efficient diagnostic value in GC. A prognostic gene signature consisted of AGT, SERPINH1 and MMP7 was constructed and showed a good performance in predicting overall survivals in TCGA. Consistently, serum levels of the three biomarkers also showed high sensitivity and specificity in distinguishing GC patients from controls. In addition, the expression level of the three biomarkers were associated with malignant degree and decreased after surgery in GC patients. Moreover, the expression level of AGT and MMP7 in exosomes correlated positively with serum level. The exosomes derived from serum of GC patients can promote migration of SGC‐7901 cells. After neutralized the expression level of three proteins in exosomes with antibodies, the migration of GC cells was obviously suppressed.

Conclusions

Our findings provided a novel strategy to identify diagnostic biomarkers based on public datasets, and suggested that the three-gene signature was a candidate diagnostic and prognostic biomarker for patients with GC.

Tetraspanins: Novel Molecular Regulators of Gastric Cancer

Gastric cancer is the fourth and fifth most common cancer worldwide in men and women, respectively. However, patients with an advanced stage of gastric cancer still have a poor prognosis and low overall survival rate. The tetraspanins belong to a protein superfamily with four hydrophobic transmembrane domains and 33 mammalian tetraspanins are ubiquitously distributed in various cells and tissues. They interact with other membrane proteins to form tetraspanin-enriched microdomains and serve a variety of functions including cell adhesion, invasion, motility, cell fusion, virus infection, and signal transduction. In this review, we summarize multiple utilities of tetraspanins in the progression of gastric cancer and the underlying molecular mechanisms. In general, the expression of TSPAN8, CD151, TSPAN1, and TSPAN4 is increased in gastric cancer tissues and enhance the proliferation and invasion of gastric cancer cells, while CD81, CD82, TSPAN5, TSPAN9, and TSPAN21 are downregulated and suppress gastric cancer cell growth. In terms of cell motility regulation, CD9, CD63 and CD82 are metastasis suppressors and the expression level is inversely associated with lymph node metastasis. We also review the clinicopathological significance of tetraspanins in gastric cancer including therapeutic targets, the development of drug resistance and prognosis prediction. Finally, we discuss the potential clinical value and current limitations of tetraspanins in gastric cancer treatments, and provide some guidance for future research.

hsa‑miR‑5580‑3p inhibits oral cancer cell viability, proliferation and migration by suppressing LAMC2

The present study aimed to explore whether and how microRNA-5580-3p (miR-5580-3p) affected oral cancer (OC) cell phenotypes via regulation of laminin subunit γ2 (LAMC2). Bioinformatics analysis was used to identify miR-5580-3p/LAMC2, a novel interactome that, to the best of our knowledge, has not been studied previously in OC. In the present study, the expression levels of miR-5580-3p and LAMC2 were detected by reverse transcription-quantitative PCR, while the protein expression levels of LAMC2 were identified using western blotting. To determine the effects of miR-5580-3p and LAMC2 in OC, a number of experiments, including Cell Counting Kit-8, 5-bromo-2′-deoxyuridine cell proliferation and wound healing migration assays, were performed using OC SCC-4 and Cal-27 cell lines. Additionally, luciferase reporter assays were employed to examine the interaction between miR-5580-3p and LAMC2 mRNA. The results demonstrated that miR-5580-3p expression was downregulated, while LAMC2 expression was upregulated in OC tissues and cell lines. In addition to the observation that miR-5580-3p promoted the malignant phenotypes of OC, it was also revealed that miR-5580-3p inhibited OC cell viability, proliferation and migration by suppressing LAMC2. Therefore, the present study suggested that miR-5580-3p and LAMC2 may be potential biomarkers and therapeutic targets for OC diagnosis and therapies in the future.

MicroRNAs and angiogenesis: a new era for the management of colorectal cancer

MicroRNAs (miRNAs) are a class of small noncoding RNA molecules containing only 20–22 nucleotides. MiRNAs play a role in gene silencing and translation suppression by targeting and binding to mRNA. Proper control of miRNA expression is very important for maintaining a normal physiological environment because miRNAs can affect most cellular pathways, including cell cycle checkpoint, cell proliferation, and apoptosis pathways, and have a wide range of target genes. With these properties, miRNAs can modulate multiple signalling pathways involved in cancer development, such as cell proliferation, apoptosis, and migration pathways. MiRNAs that activate or inhibit the molecular pathway related to tumour angiogenesis are common topics of research. Angiogenesis promotes tumorigenesis and metastasis by providing oxygen and diffusible nutrients and releasing proangiogenic factors and is one of the hallmarks of tumour progression. CRC is one of the most common tumours, and metastasis has always been a difficult issue in its treatment. Although comprehensive treatments, such as surgery, radiotherapy, chemotherapy, and targeted therapy, have prolonged the survival of CRC patients, the overall response is not optimistic. Therefore, there is an urgent need to find new therapeutic targets to improve CRC treatment. In a series of recent reports, miRNAs have been shown to bidirectionally regulate angiogenesis in colorectal cancer. Many miRNAs can directly act on VEGF or inhibit angiogenesis through other pathways (HIF-1a, PI3K/AKT, etc.), while some miRNAs, specifically many exosomal miRNAs, are capable of promoting CRC angiogenesis. Understanding the mechanism of action of miRNAs in angiogenesis is of great significance for finding new targets for the treatment of tumour angiogenesis. Deciphering the exact role of specific miRNAs in angiogenesis is a challenge due to the high complexity of their actions. Here, we describe the latest advances in the understanding of miRNAs and their corresponding targets that play a role in CRC angiogenesis and discuss possible miRNA-based therapeutic strategies.

Regulation of Formation, Stemness and Therapeutic Resistance of Cancer Stem Cells

Over the past 20 years cancer stem cells (CSCs) have been proposed as key players in the tumorigenesis and progression, which are closely related to the initiation, metastasis and therapeutic resistance of cancer. Evidences have been provided that both genetic and epigenetic factors contribute to the regulation of the formation and stemness maintenance as well as the therapeutic resistance of CSCs via affecting various signal pathways. In addition, the interaction between CSCs and tumor microenvironment has also been revealed to be involved in the above-described processes. With the aim of targeting CSCs to improve treatment outcome, we herein discuss the mechanisms that orchestrate the characteristic of CSCs by the three elements and potential therapeutic strategies. We also summarize how several key regulatory factors function in the regulation of not only the formation and stemness maintenance, but also the therapeutic resistance of CSCs. Thus, future studies focusing on these key factors would be helpful for the development of novel drugs targeting CSCs.

Alpha-enolase (ENO1), identified as an antigen to monoclonal antibody 12C7, promotes the self-renewal and malignant phenotype of lung cancer stem cells by AMPK/mTOR pathway

BACKGROUND

Tumor-associated antigens (TAAs) can be targeted in cancer therapy. We previously identified a monoclonal antibody (mAb) 12C7, which presented anti-tumor activity in lung cancer stem cells (LCSCs). Here, we aimed to identify the target antigen for 12C7 and confirm its role in LCSCs.

METHODS

Immunofluorescence was used for antigen localization. After targeted antigen purification by electrophoresis and immunoblot, the antigen was identified by LC-MALDI-TOF/TOF mass spectrometry, immunofluorescence, and immunoprecipitation. The overexpression or silence of ENO1 was induced by lentiviral transduction. Self-renewal, growth, and invasion of LCSCs were evaluated by sphere formation, colony formation, and invasion assay, respectively. High-throughput transcriptome sequencing (RNA-seq) and bioinformatics analysis were performed to analyze downstream targets and pathways of targeted antigen.

RESULTS

Targeted antigen showed a surface antigen expression pattern, and the 43-55 kDa protein band was identified as α-enolase (ENO1). Self-renewal, growth, and invasion abilities of LCSCs were remarkably inhibited by ENO1 downregulation, while enhanced by ENO1 upregulation. RNA-seq and bioinformatics analysis eventually screened 4 self-renewal-related and 6 invasion-related differentially expressed genes. GSEA analysis and qRT-PCR verified that ENO1 regulated self-renewal, invasion-related genes, and pathways. KEGG pathway analysis and immunoblot demonstrated that ENO1 inactivated AMPK pathway and activated mTOR pathway in LCSCs.

CONCLUSIONS

ENO1 is identified as a targeted antigen of mAb 12C7 and plays a pivotal role in facilitating self-renewal, growth, and invasion of LCSCs. These findings provide a potent therapeutic target for the stem cell therapy for lung cancer and have potential to improve the anti-tumor activity of 12C7.

Regulation of breast cancer metastasis signaling by miRNAs

Despite the decline in death rate from breast cancer and recent advances in targeted therapies and combinations for the treatment of metastatic disease, metastatic breast cancer remains the second leading cause of cancer-associated death in U.S. women. The invasion-metastasis cascade involves a number of steps and multitudes of proteins and signaling molecules. The pathways include invasion, intravasation, circulation, extravasation, infiltration into a distant site to form a metastatic niche, and micrometastasis formation in a new environment. Each of these processes is regulated by changes in gene expression. Noncoding RNAs including microRNAs (miRNAs) are involved in breast cancer tumorigenesis, progression, and metastasis by post-transcriptional regulation of target gene expression. miRNAs can stimulate oncogenesis (oncomiRs), inhibit tumor growth (tumor suppressors or miRsupps), and regulate gene targets in metastasis (metastamiRs). The goal of this review is to summarize some of the key miRNAs that regulate genes and pathways involved in metastatic breast cancer with an emphasis on estrogen receptor α (ERα+) breast cancer. We reviewed the identity, regulation, human breast tumor expression, and reported prognostic significance of miRNAs that have been documented to directly target key genes in pathways, including epithelial-to-mesenchymal transition (EMT) contributing to the metastatic cascade. We critically evaluated the evidence for metastamiRs and their targets and miRNA regulation of metastasis suppressor genes in breast cancer progression and metastasis. It is clear that our understanding of miRNA regulation of targets in metastasis is incomplete.

MicroRNA-633 enhances melanoma cell proliferation and migration by suppressing KAI1

The aim of the present study was to determine the impact of microRNA (miRNA/miR)-633 on the biological properties of malignant melanoma cells. Kang-Ai 1 (KAI1), also known as cluster of differentiation 82, is an important transcriptional regulator and tumor suppressor gene present in different types of tumors. miRNAs that potentially bind with KAI1 were predicted via bioinformatics analyses. In total, six putative miRNA regulators of KAI1 were identified in the present analysis, among which miR-633 was upregulated the most in melanoma tissues compared with the control group. The expression levels of miR-633 and KAI1 in melanoma tissues compared with adjacent normal tissues were then assessed. It was found that miR-633 was significantly upregulated in melanoma cells compared with the control group, whereas the expression levels of KAI1 showed the opposite results. miR-633 was predicted to target the 3'-untranslated region of KAI1 using predictive online tools, and results from luciferase reporter assays confirmed the direct regulation of KAI1 promoter activity by miR-633. Furthermore, miR-633 mimics over expression was shown to suppress both mRNA and protein expression of KAI1, while miR-633 inhibition resulted in decreased viability and migrationin melanoma cells in vitro. Taken together, the present study demonstrated, to the best of the authors' knowledge for the first time, that miR-633 exerts an important role in melanoma through targeting KAI1.

EBV-miR-BART10-3p and EBV-miR-BART22 promote metastasis of EBV-associated gastric carcinoma by activating the canonical Wnt signaling pathway

PURPOSE

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) constitutes the largest subpopulation in EBV-associated tumors worldwide. To date, 44 mature EBV-encoded microRNAs (EBV miRNAs) have been identified, but their roles in EBVaGC development are still poorly understood. In this study, we aimed to investigate the roles and targets of ebv-miR-BART10-3p (BART10-3p) and ebv-miR-BART22 (BART22) in EBVaGC.

METHODS

EBV miRNA expression in EBVaGCs was evaluated by deep sequencing and qRT-PCR, and relationships between BART10-3p or BART22 expression and clinicolpathological characteristics and survival rates of patients with EBVaGC were analyzed. The roles of BART10-3p and BART22 and their underlying mechanisms were further investigated through exogenous overexpression or silencing in EBVaGC cells, and validated in clinical EBVaGC tissue samples.

RESULTS

BART10-3p and BART22 were found to be highly expressed in the EBVaGC cell lines SNU719 and YCCEL1. Higher expression of BART10-3p or BART22 in primary EBVaGC samples was significantly associated with lymph node metastasis and a worse 5-year overall survival. BART10-3p and BART22 promoted cell migration and invasion by targeting adenomatous polyposis coli (APC) and Dickkopf 1 (DKK1), thereby activating the Wnt signaling pathway and, consequently, upregulating downstream Twist and downregulating downstream E-cadherin. In 874 primary gastric carcinoma samples, APC and DKK1 were found to be lower expressed in EBVaGC than in EBV-negative samples, and their expression levels were inversely correlated with those of BART10-3p and BART22 in 71 EBVaGC samples.

CONCLUSIONS

From our data we conclude that BART10-3p and BART22 play vital roles in promoting EBVaGC metastasis by targeting APC and DKK1 and, subsequently, activating the Wnt signaling pathway, thereby providing novel prognostic biomarkers and potential therapeutic targets for EBVaGC.

miR-622 is a novel potential biomarker of breast carcinoma and impairs motility of breast cancer cells through targeting NUAK1 kinase

BACKGROUND

Aberrant expression of microRNAs (miR) has been proposed as non-invasive biomarkers for breast cancers. The aim of this study was to analyse the miR-622 level in the plasma and in tissues of breast cancer patients and to explore the role of miR-622 and its target, the NUAK1 kinase, in this context.

METHODS

miR-622 expression was analysed in plasma and in tissues samples of breast cancer patients by q-RT-PCR. Bioinformatics programs, luciferase assay, public dataset analysis and functional experiments were used to uncover the role of miR-622 and its target in breast cancer cells.

RESULTS

miR-622 is downregulated in plasma and in tissues of breast cancer patients respect to healthy controls and its downregulation is significantly associated with advanced grade and high Ki67 level. Modulation of miR-622 affects the motility phenotype of breast cancer cells. NUAK1 kinase is a functional target of miR-622, it is associated with poor clinical outcomes of breast cancer patients and is inversely correlated with miR-622 level.

CONCLUSIONS

miR-622/NUAK1 axis is deregulated in breast cancer patients and affects the motility phenotype of breast cancer cells. Importantly, miR-622 and NUAK1 hold promises as biomarkers and as targets for breast cancers.

Silencing of LAMC2 Reverses Epithelial-Mesenchymal Transition and Inhibits Angiogenesis in Cholangiocarcinoma via Inactivation of the Epidermal Growth Factor Receptor Signaling Pathway

Cholangiocarcinoma (CCA) is a malignant cancer that is associated with high mortality rates. The relationship between laminin γ 2 chain gene (LAMC2) and epidermal growth factor receptor (EGFR) has been previously documented in gastric cancer and oral squamous cell carcinoma. This study investigates the role of LAMC2 in epithelial-mesenchymal transition (EMT) and angiogenesis in CCA and explores the underlying mechanism(s). Differentially expressed genes related to CCA were initially screened using a microarray analysis, and the interaction between LAMC2 and the EGFR signaling pathway was identified. To determine the regulatory effects of LAMC2 on CCA progression, LAMC2 was silenced or overexpressed and the EGFR signaling pathway was activated or blocked. Subsequently, the regulation effects of LAMC2 were evaluated on the expression of EMT markers, invasion and migration of CCA cells, as well as microvessel density in nude mice. Microarray analysis demonstrated that highly expressed LAMC2 is linked to CCA development, which involves the EGFR signaling pathway. When LAMC2 expression was increased, the EGFR signaling pathway and EMT were activated in CCA tissues. Silencing of LAMC2 as well as EGFR signaling pathway inhibition led to suppression of EMT, cell invasion, and migration abilities in vitro, as well as angiogenesis in vivo. This study demonstrates that LAMC2 silencing suppresses the activity of the EGFR signaling pathway, thus functioning as a tumor suppressor in CCA.

Drosha-independent miR-6778-5p strengthens gastric cancer stem cell stemness via regulation of cytosolic one-carbon folate metabolism

Drosha-dependent canonical microRNAs (miRNAs) play a crucial role in the biological functions and development of cancer. However, the effects of Drosha-independent non-canonical miRNAs remain poorly understood. In our previous work, we found a set of aberrant miRNAs, including some upregulated miRNAs, called Drosha-independent noncanonical miRNAs, in Drosha-knockdown gastric cancer (GC) cells. Surprisingly, Drosha-silenced GC cells still retained strong malignant properties (e.g., proliferation ability and cancer stem cell (CSC) characteristics), indicating that aberrantly upregulated non-canonical miRNAs may play an important role in the maintenance of the malignant properties in GC cells that express low Drosha levels. Here, we report that miR-6778-5p, a noncanonical miRNA, acts as a crucial regulator for maintenance of CSC stemness in Drosha-silenced GC cells. MiR-6778-5p belongs to the 5'-tail mirtron type of non-canonical miRNAs and is transcript splice-derived from intron 5 of SHMT1 (coding cytoplasmic serine hydroxymethyltransferase). It positively regulates expression of its host gene, SHMT1, via targeting YWHAE in Drosha-knockdown GC cells. Similar to its family member SHMT2, SHMT1 plays a crucial role in folate-dependent serine/glycine inter-conversion in one-carbon metabolism. In Drosha wild type GC cells, SHMT2 mediates a mitochondrial-carbon metabolic pathway, which is a major pathway of one-carbon metabolism in normal cells and most cancer cells. However, in Drosha-silenced or Drosha low-expressing GC cells, miR-6778-5p positively regulates SHMT1, instead of SHMT2, thus mediating a compensatory activation of cytoplasmic carbon metabolism that plays an essential role in the maintenance of CSCs in gastric cancer (GCSCs). Drosha wild type GCSCs with SHMT2 are sensitive to 5-fluorouracil; however, Drosha low-expressing GCSCs with SHMT1 are 5-FU-resistant. The loss of miR-6778-5p or SHMT1 notably mitigates GCSC sphere formation and increases sensitivity to 5-fluorouracil in Drosha-knockdown gastric cancer cells. Thus, our study reveals a novel function of Drosha-independent noncanonical miRNAs in maintaining the stemness of GCSCs.

Identification of HGF as a novel target of miR-15a/16/195 in gastric cancer

Background Gastric malignancy is the third most frequently encountered cancer globally and have been documented to confer extremely poor prognosis, given their limited treatment options. The up-regulation of hepatocyte growth factor (HGF) has been found in various tumor tissues, including GC tissue, and has been linked with tumor development. Nevertheless, the pathways leading to HGF upregulation have yet to be fully explored. Methods Immunohistochemistry (IHC) assay was used to detect HGF expression in human gastric tumor tissues, while western blotting allowed quantification of protein levels. Bioinformatics tools were used to predict potential miRNA that may target HGF mRNA. Relative levels of miR-15a/16/195 as well as the target mRNA levels were analyzed with qRT-PCR. Direct targeting between miRNA and mRNA was then validated by luciferase assay. Finally, a mouse xenograft tumor model was selected to demonstrate the in vivo effects of miR-15a/16/195. Results HGF protein expressions were markedly raised, while miR-15a/16/195 levels were dramatically down-regulated in tumor tissues of GC. miR-15a/16/195 were shown to directly bind with the 3'-UTR of HGF mRNA. This study demonstrated that HGF can be repressed by overexpressed miR-15a/16/195, which resulted in the suppression of GC cell proliferation and migration. Furthermore, in the xenograft mouse model, miR-15a/16/195 were also found to have a tumor growth suppression effect. Conclusions miR-15a/16/195 suppresses tumorigenesis by targeting HGF and may have a potential therapeutic application in the clinical treatment of GC.

An overview of the multifaceted roles of miRNAs in gastric cancer: Spotlight on novel biomarkers and therapeutic targets

MicroRNAs (miRNAs) are a group of small non-coding RNAs that have displayed strong association with gastric cancer (GC). Through the repression of target mRNAs, miRNAs regulate many biological pathways that are involved in cell proliferation, apoptosis, migration, invasion, metastasis as well as drug resistance. The detection of miRNAs in tissues and in body fluids emerges as a promising method in the diagnosis and prognosis of GC, due to their unique expression pattern in correlation with GC. Notably, miRNAs are also identified as potential therapeutic targets for GC therapy. The present review is thus to highlight the multifaceted roles of miRNAs in GC and in GC therapies, which would give indications for future research.

Intracellular citrate accumulation by oxidized ATM-mediated metabolism reprogramming via PFKP and CS enhances hypoxic breast cancer cell invasion and metastasis

Citrate, a substance being related to de novo fatty acid synthesis and tricarboxylic acid (TCA) cycle, has a pivotal role in cell survival. However, the molecular mechanisms that regulate intracellular citrate in triple-negative breast cancer (TNBC), especially under hypoxic condition, remain poorly understood. Here we find that hypoxia (1% O2) induces DNA damage-independent ATM activation (oxidized ATM) and suppression of oxidized ATM reduces intracellular citrate via decreasing the levels of phosphofructokinase (PFKP) and citrate synthase (CS), two key glucose metabolism-associated enzymes. Mechanistically, PFKP is regulated by HIF1A at the translational level, whereas CS is of posttranscriptional regulation by UBR5-mediated ubiquitination. Interestingly, accumulation of citrate in cytoplasm or exogenous citrate significantly enhances cell migration, invasion, and metastasis of hypoxic TNBC cells in vitro and in mice xenografts. The underlying mechanism mainly involves citrate-stimulated activation of the AKT/ERK/MMP2/9 signaling axis. Our findings unravel a novel function of oxidized ATM in promoting migration, invasion, and metastasis of TNBC.

miR-622 inhibits angiogenesis by suppressing the CXCR4-VEGFA axis in colorectal cancer

Angiogenesis is essential for tumor metastasis. Our previous study has revealed that miR-622 inhibits colorectal cancer (CRC) metastasis. Here, we aimed to explore the effects and potential molecular mechanisms of action of miR-622 on angiogenesis. We found that overexpression of miR-622 inhibited CRC angiogenesis in vitro, according to suppression of proliferation, migration, tube formation, and invasiveness of human umbilical vein endothelial cells (HUVECs) treated with a tumor cell-conditioned medium derived from Caco-2 or HT-29 cells. Likewise, enhanced miR-622 expression suppressed CRC angiogenesis in vivo as determined by the measurement of Ki67 and VEGFA levels and microvessel density (by immunostaining). CXCR4, encoding a positive regulator of vascular endothelial growth factor A (VEGFA), was shown to be a direct target of miR-622. Overexpression of CXCR4 attenuated the inhibition of VEGFA expression by miR-622 and reversed the loss of tumor angiogenesis caused by miR-622. Taken together, these data show that miR-622 inhibits CRC angiogenesis by suppressing the CXCR4-VEGFA signaling axis, which represents a promising target for developing a new therapeutic strategy against CRC.

Perineural invasion of cancer: a complex crosstalk between cells and molecules in the perineural niche

Perineural invasion (PNI) can be found in a variety of malignant tumors. It is a sign of tumor metastasis and invasion and portends the poor prognosis of patients. The pathological description and clinical significance of PNI are clearly understood, but exploration of the underlying molecular mechanism is ongoing. It was previously thought that the low-resistance channel in the anatomic region led to the occurrence of PNI. However, with rapid development of precision medicine and molecular biology, we have gradually realized that the occurrence of PNI is not the result of a single factor. The latest study suggests that PNI of cancer is a continuous and multistep process. A specific peripheral microenvironment, also called the perineural niche, is formed by neural cells, supporting cells, recruited inflammatory cells, altered extracellular matrix, blood vessels, and immune components in the background of carcinoma. Various soluble signaling molecules and their receptors comprise a complex signal network, which achieves the interaction between nerve and tumor. Nerve cells and tumor cells can interact directly or through the opening and closing of the signal transduction pathways and/or the recognition and response of the ligands and receptors. The information is transferred to the targets accurately and effectively, leading to the specific interactions between the nerve cells and the malignant tumor cells. PNI occurs through changes in nerve cells and supporting cells in the background of cancer; change and migration of the perineural matrix; enhancement of the viability, mobility, and invasiveness of the tumor cells; injury and regeneration of nerve cells; interaction, chemotactic movement, contact, and adherence of the nerve cells and the tumor cells; escape from autophagy, apoptosis, and immunological surveillance of tumor cells; and so on. Certainly, exploring the mechanism of PNI clearly has great significance for blocking tumor progression and improving patient survival. The current review aims to elucidate the cellular and molecular mechanisms of PNI, which may help us find a strategy for improving the prognosis of malignant tumors.

Biomarkers of gastric cancer: Current topics and future perspective

Gastric cancer (GC) is one of the most prevalent malignant types in the world and an aggressive disease with a poor 5-year survival. This cancer is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Although the incidence is declining, the outcome of patients with GC remains dismal. Thus, the detection at an early stage utilizing useful screening approaches, selection of an appropriate treatment plan, and effective monitoring is pivotal to reduce GC mortalities. Identification of biomarkers in a basis of clinical information and comprehensive genome analysis could improve diagnosis, prognosis, prediction of recurrence and treatment response. This review summarized the current status and approaches in GC biomarker, which could be potentially used for early diagnosis, accurate prediction of therapeutic approaches and discussed the future perspective based on the molecular classification and profiling.