MiR-338-3p inhibits epithelial-mesenchymal transition in gastric cancer cells by targeting ZEB2 and MACC1/Met/Akt signaling

The role of Aha1 in cancer and neurodegeneration

The 90 kDa Heat shock protein (Hsp90) is a family of ubiquitously expressed molecular chaperones responsible for the stabilization and maturation of >400 client proteins. Hsp90 exhibits dramatic conformational changes to accomplish this, which are regulated by partner proteins termed co-chaperones. One of these co-chaperones is called the activator or Hsp90 ATPase activity homolog 1 (Aha1) and is the most potent accelerator of Hsp90 ATPase activity. In conditions where Aha1 levels are dysregulated including cystic fibrosis, cancer and neurodegeneration, Hsp90 mediated client maturation is disrupted. Accumulating evidence has demonstrated that many disease states exhibit large hetero-protein complexes with Hsp90 as the center. Many of these include Aha1, where increased Aha1 levels drive disease states forward. One strategy to block these effects is to design small molecule disruptors of the Hsp90/Aha1 complex. Studies have demonstrated that current Hsp90/Aha1 small molecule disruptors are effective in both models for cancer and neurodegeration.

miRNAs and related genetic biomarkers according to the WHO glioma classification: From diagnosis to future therapeutic targets

In the 2021 WHO classification of Tumors of the Central Nervous System, additional molecular characteristics have been included, defining the following adult-type diffuse glioma entities: Astrocytoma IDH-mutant, Oligodendroglioma IDH-mutant and 1p/19q-codeleted, and Glioblastoma IDH-wildtype. Despite advances in genetic analysis, precision oncology, and targeted therapy, malignant adult-type diffuse gliomas remain "hard-to-treat tumors", indicating an urgent need for better diagnostic and therapeutic strategies. In the last decades, miRNA analysis has been a hotspot for researching and developing diagnostic, prognostic, and predictive biomarkers for various disorders, including brain cancer. Scientific interest has recently been directed towards therapeutic applications of miRNAs, with encouraging results. Databases such as NCBI, PubMed, and Medline were searched for a selection of articles reporting the relationship between deregulated miRNAs and genetic aberrations used in the latest WHO CNS classification. The current review discussed the recommended molecular biomarkers and genetic aberrations based on the 2021 WHO classification in adult-type diffuse gliomas, along with associated deregulated miRNAs. Additionally, the study highlights miRNA-based treatment advancements in adults with gliomas.

Mir-338-3p targeting THBS1 attenuates glioma progression by inhibiting the PI3K/Akt pathway

BACKGROUND

Glioma is a brain tumor with high morbidity and mortality rates. Understanding its molecular pathogenesis can provide targets and therapeutic strategies for glioma treatment. miR-338-3p represses tumor growth in several cancers, including glioma. Thus, this study aimed to identify the regulatory effects of miR-338-3p/phosphoinositide 3-kinase (PI3K)/Akt/thrombospondins 1 (THBS1) on glioma progression.

MATERIALS AND METHODS

Quantitative reverse transcription polymerase chain reaction and western blotting were performed to evaluate the levels of miR-338-3p, THBS1, and PI3K/Akt phosphorylation-related proteins. TargetScan software predicted that miR-338-3p targeted THBS1. This was confirmed by performing the dual-luciferase assay. Wound-healing and cell-counting-kit-8 experiments were performed to analyze how THBS1 and miR-338-3p affect the ability of glioma cells to migrate and proliferate. The effect of miR-338-3p on tumorigenicity in mice was also analyzed.

RESULTS

miR-338-3p downregulation was observed in gliomas, whereas THBS1 showed the opposite trend. By suppressing the PI3K/Akt signaling pathway activation, miR-338-3p overregulated the ability of glioma cells to migrate and proliferate in vitro. Additionally, miR-338-3p inhibited the development of glioma tumors in vivo. Moreover, miR-338-3p directly targeted THBS1. THBS1 overexpression promoted glioma cell migration and proliferation by increasing PI3K/Akt phosphorylation. Nonetheless, miR-338-3p overregulation alleviated the effects of THBS1 overexpression.

CONCLUSION

The miR-338-3p/PI3K/Akt/THBS1 regulatory axis can modulate the progression of glioma cell proliferation and migration; thus, it can be considered a therapeutic biomarker.

miRNA/epithelial-mesenchymal axis (EMT) axis as a key player in cancer progression and metastasis: A focus on gastric and bladder cancers

The metastasis a major hallmark of tumors that its significant is not only related to the basic research, but clinical investigations have revealed that majority of cancer deaths are due to the metastasis. The metastasis of tumor cells is significantly increased due to EMT mechanism and therefore, inhibition of EMT can reduce biological behaviors of tumor cells and improve the survival rate of patients. One of the gaps related to cancer metastasis is lack of specific focus on the EMT regulation in certain types of tumor cells. The gastric and bladder cancers are considered as two main reasons of death among patients in clinical level. Herein, the role of EMT in regulation of their progression is evaluated with a focus on the function of miRNAs. The inhibition/induction of EMT in these cancers and their ability in modulation of EMT-related factors including ZEB1/2 proteins, TGF-β, Snail and cadherin proteins are discussed. Moreover, lncRNAs and circRNAs in crosstalk of miRNA/EMT regulation in these tumors are discussed and final impact on cancer metastasis and response of tumor cells to the chemotherapy is evaluated. Moreover, the impact of miRNAs transferred by exosomes in regulation of EMT in these cancers are discussed.

MACC1 and MET as markers associated with progression and metastasis in cutaneous melanoma

Cutaneous melanoma is the most common lethal malignancy among skin cancers and has a high propensity for metastasis. Understanding the mechanisms governing tumorigenesis, progression and metastasis as well as identifying biomarkers guiding risk stratification and management of the disease is essential. MACC1 has been found to play key roles in cancer cell migration, invasion, epithelial-to-mesenchymal transition, and metastasis in various types of cancer, through activation of MET signaling. In this study, we examined the extent of MACC1 and MET protein expression by immunohistochemical staining in a tissue microarray constructed from twenty-three melanomas and ten melanocytic nevi. We observed significantly higher levels of MACC1 expression on average in metastatic melanomas, comparing to primary melanomas and nevi. MET expression in metastatic melanomas was also significantly higher than in nevi. MACC1 expression does not appear to correlate with MET expression in nevi and primary melanomas. However, this correlation appears stronger in metastatic melanomas, where seven (78%) of nine cases show intermediate to high expression of both MACC1 and MET. The expressions of MACC1 and MET do not show significant differences based on other clinicopathologic factors including patient age, gender, histologic subtypes, depth of invasion, and staging. Our study suggests that high expression of MACC1 or both MACC1 and MET is associated with metastasis of cutaneous melanoma.

The estrogen/miR-338-3p/ADAM17 axis enhances the viability of breast cancer cells via suppressing NK cell's function

Natural killer (NK) cells are the critical elements of the innate immune response and implicated in rapidly recognizing and eliminating cancer cells. However, the tumor-suppressive ability of NK cells is often impaired in several cancer types. The critical roles of microRNAs have been elucidated by increasing evidences, while the regulation of miR-338-3p in anti-tumor activation of NK cells and its relationship with estrogen in breast cancer (BC) are still confusing. Here, miR-338-3p level was found to be significantly downregulated in BC tissues and estrogen receptor positive (ER+ ) cells, this difference was more obvious in ER+ patients or BC patients at advanced stage (TNM III and IV). MiR-338-3p level was shown to be downregulated by 17β-estradiol in BC cells (MDA-MB-231 cells and MCF-7) in vitro. MiR-338-3p overexpression decreased disintegrin and metalloprotease-17 (ADAM17) secretion in MDA-MB-231 (ER- ) and MCF-7 (ER+ ) cells. In addition, miR-338-3p overexpression or treatment with anti-ADAM17 antibody could down-regulate granzyme B, CD16, and NKG2D in NK cells, which was reversed by human recombinant ADAM17. Furthermore, these educated NK cells could promote the viability of MDA-MB-231 or MCF-7 cells. Taken together, our results demonstrate that miR-338-3p was negatively regulated by estrogen in BC cells, impairing NK cell's activity by the up-regulation of ADAM17, and conversely promoted the viability of BC cells. Therefore, the estrogen/miR-338-3p/ADAM17 axis is critically implicated in BC pathogenesis and may provide potential targets for BC diagnosis and treatment.

MACC1 and Gasdermin-E (GSDME) regulate the resistance of colorectal cancer cells to irinotecan

Metastasis-associated in colon cancer 1 (MACC1) is an oncogene associated with the progression and metastasis of many solid cancer entities. High expression of MACC1 is found in colorectal cancer (CRC) tissues. So far, the role of MACC1 in CRC cell pyroptosis and resistance to irinotecan is unclear. The cleavage of Gasdermin-E (GSDME) is the main executors of activated pyroptosis. We found that GSDME enhanced CRC cell pyroptosis and reduced their resistance to irinotecan, while MACC1 inhibited the cleavage of GSDME and CRC cell pyroptosis, promoted CRC cell proliferation, and enhanced the resistance of CRC cells to irinotecan. Therefore, CRC cells with high MACC1 expression and low GSDME expression had higher resistance to irinotecan, while CRC cells with low MACC1 expression and high GSDME expression had lower resistance to irinotecan. Consistently, by analyzing CRC patients who received FOLFIRI (Fluorouracil + Irinotecan + Leucovorin) in combination with chemotherapy in the GEO database, we found that CRC patients with low MACC1 expression and high GSDME expression had higher survival rate. Our study suggests that the expression of MACC1 and GSDME can be used as detection markers to divide CRC patients into irinotecan resistant and sensitive groups, helping to determine the treatment strategy of patients.

Role of Some microRNA/ADAM Proteins Axes in Gastrointestinal Cancers as a Novel Biomarkers and Potential Therapeutic Targets—A Review

Gastrointestinal (GI) cancers are some of the most common cancers in the world and their number is increasing. Their etiology and pathogenesis are still unclear. ADAM proteins are a family of transmembrane and secreted metalloproteinases that play a role in cancerogenesis, metastasis and neoangiogenesis. MicroRNAs are small single-stranded non-coding RNAs that take part in the post-transcriptional regulation of gene expression. Some ADAM proteins can be targets for microRNAs. In this review, we analyze the impact of microRNA/ADAM protein axes in GI cancers.

MACC1-induced migration in tumors: Current state and perspective

Malignant tumors are still a global, heavy health burden. Many tumor types cannot be treated curatively, underlining the need for new treatment targets. In recent years, metastasis associated in colon cancer 1 (MACC1) was identified as a promising biomarker and drug target, as it is promoting tumor migration, initiation, proliferation, and others in a multitude of solid cancers. Here, we will summarize the current knowledge about MACC1-induced tumor cell migration with a special focus on the cytoskeletal and adhesive systems. In addition, a brief overview of several in vitro models used for the analysis of cell migration is given. In this context, we will point to issues with the currently most prevalent models used to study MACC1-dependent migration. Lastly, open questions about MACC1-dependent effects on tumor cell migration will be addressed.

microRNA-338-3p suppresses lipopolysaccharide-induced inflammatory response in HK-2 cells

BACKGROUND

Inflammation is the most common cause of kidney damage, and inflammatory responses in a number of diseases are mediated by microRNA-338-3p (miR-338-3p). However, there are only a few reports which described the regulation of miR-338-3p in human proximal tubular cells. The goal of this study was to see how miR-338-3p affected lipopolysaccharide (LPS)-caused inflammatory response in HK-2 cells.

METHODS

LPS was used to construct an inflammatory model in HK-2 cells. miR-338-3p mimic was used to increase the levels of miR-338-3p in HK-2 cells. MTT, JC-1 staining, and apoptosis assays were used to detect cell viability, mitochondrial membrane potential (MMP), and apoptosis, respectively. The production of inflammatory factors and the levels of p38, p65, phospho-p65, phospho-p38, Bax, Bcl-2, cleaved caspase-9, and cleaved caspase-3 were investigated using real-time polymerase chain reaction, western blotting, or enzyme-linked immunosorbent assay.

RESULTS

The levels of miR-338-3p were significantly lower in serum from patients with sepsis-induced kidney injury compared to the serum from healthy volunteers (P < 0.05). LPS reduced the level of miR-338-3p in HK-2 cells (P < 0.05). HK-2 cell viability, mitochondrial membrane potential, and Bcl-2 mRNA and protein levels were decreased by LPS (all P < 0.05). Apoptosis, the mRNA and protein levels of inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) and Bax, and the levels of cleaved caspase-9 and caspase-3 were increased by LPS (all P < 0.05). Raising the level of miR-338-3p mitigated these effects of LPS (all P < 0.05).

CONCLUSION

LPS-induced inflammation in HK-2 cells is reduced by miR-338-3p.

Construction of a transcription factor-miRNA-mRNA interactive network elucidates underlying pathogenesis for osteosarcoma and validation by qRT-PCR

PURPOSE

Osteosarcoma is characterized by features of rapid growth and early metastasis with a poor prognosis. The aim of our research is to investigate the potential transcription factor (TF)-miRNA-mRNA regulatory mechanism in osteosarcoma utilizing bioinformatics methods and validate by qRT-PCR.

METHODS

The microRNA (miRNA) expression profiling datasets (GSE28423 and GSE65071) and mRNA expression profiling dataset GSE33382 were collected from the Gene Expression Omnibus (GEO) database. Differentially expressed miRNAs (DEMs) and differentially expressed genes (DEGs) were screened using the limma package. Then, the TransmiR v2.0, miRDB, and Targetscan 7.2 database were applied for the acquisition of TF-miRNA and miRNA-mRNA interaction relationships, respectively. Finally, we built a TF-miRNA-mRNA interactive network. Furthermore, survival analysis was performed to identify sub-network with prognostic value and validate through qRT-PCR.

RESULTS

Eight overlapping DEMs and 682 DEGs were identified. Based on bioinformatics methods, 30 TF-miRNA interaction pairs and 25 miRNA-mRNA interaction pairs were screened. Finally, we constructed a TF-miRNA-mRNA regulatory network. Furthermore, laminin subunit gamma 1 (LAMC1) and thrombospondin-1 (THBS1), which involved in the network, were determined to have prognostic value and the corresponding subnetwork was identified. qRT-PCR results showed that LAMC1 mRNA expression was higher in osteosarcoma cells.

CONCLUSION

Based on the survival analysis, a TF-miRNA-mRNA sub-network, that is TFs (SPI1, HEY1, and CEBPB)-hsa-miR-338-3p-target genes (LAMC1 and THBS1) was established. In conclusion, the construction of a potential TF-related regulatory network will help elucidate the underlying pathological mechanisms of osteosarcoma, and may provide novel insights for the diagnosis and treatment of osteosarcoma.

Long non-coding RNA LINC00240 promotes gastric cancer progression via modulating miR-338-5p/METTL3 axis

Gastric cancer (GC) is a common cancer with high incidence. Understanding the epidemiology and physiopathology of GC is crucial for formulating novel therapeutic strategies. Recent studies have implicated long non-coding RNA LINC00240, miR-338-5p and methyltransferase-like 3 (METTL3) in the progression of GC. In this study, we investigated the functional role of LINC00240/miR-338-5p/METTL3 axis in regulating the aggressiveness of GC cells. We first demonstrated that LINC00240 was upregulated in GC tissues and GC cell lines. High expression of LINC00240 was associated with advanced TNM stage, a higher extent of distant metastasis and lymph nodes metastasis, and the poor overall and disease-free survival of the patients. In GC cell lines, the knockdown of LINC00240 inhibited GC cell proliferation and migration, but induced cell apoptosis. We further identified and validated the functional interaction between LINC00240 and miR-338-5p. miR-338-5p seemed to function as a downstream target negatively regulated by LINC00240, and miR-338-5p could target METTL3 at 3ʹ UTR to downregulate its expression. In GC tissues, the expression of miR-338-5p was negatively correlated with LINC00240, and the expression of miR-338-5p was negatively correlated with METTL3. Importantly, miR-338-5p inhibitor or METTL3 overexpression could rescue the inhibitory effect of LINC00240 knockdown on cell proliferation and migration, and inhibit the apoptosis induction in GC cells. Taken together, our data imply that the upregulation of LINC00240 in GC cells promotes the malignant phenotype by modulating miR-338-5p/METTL3 axis, which could serve as potential therapeutic targets for GC treatment.

HIPK3 Circular RNA Promotes Metastases of HCC Through Sponging miR-338-3p to Induce ZEB2 Expression

BACKGROUND

Upregulation of circHIPK3 has been observed in several kinds of malignancies. However, the mechanisms of circHIPK3 in HCC metastases remains unclear. We investigated the role and the mechanisms of circHIPK3 in the development of HCC.

METHODS

HCC tissues and paired adjacent non-tumor tissues of surgical patients were used to evaluate circHIPK3 expression. A series of biological experiments had been taken to evaluate the pro-metastatic ability of circHIPK3 during HCC development in vitro and in vivo. The potential mechanisms of circHIPK3 in HCC development were identified by RT-qPCR, Western blot, RIP, and luciferase reporter assays.

RESULTS

CircHIPK3 expression is significantly upregulated during HCC development. Overexpression of circHIPK3 promotes cell migration, invasion, and metastases in vitro and in vivo. CircHIPK3 promoted HCC metastases by sponging miR-338-3p to regulate EMT-associated proteins E-cadherin, vimentin, and ZEB2 expression.

CONCLUSION

CircHIPK3 plays a regulatory role in metastatic HCC by sponging miR-338-3p to induce ZEB2 expression, thus promoting EMT procession.

miR-511-5p Suppresses Cell Migration, Invasion and Epithelial-Mesenchymal Transition Through Targeting PAK2 in Gastric Cancer

As a malignant tumor, gastric cancer (GC) is closely related with gastric mucosa and has a high mortality in the world. Since microRNA (miRNA) has become more and more important in tumor research, we intend to find out the functional role and mechanism of miR-511-5p in GC. Firstly, miR-511-5p level was examined in human GC cell lines and tissues, and its effect on cell migration and invasion of BGC-823 or HGC-27 cells was tested by migration assay and transwell assay. Then, we confirmed the association between miR-511-5p and p21 activated kinase 2 (PAK2) by the luciferase reporter assay, and further assessed their role in cell migration and invasion. Moreover, we verified the function of miR-511-5p and PAK2 in epithelial-mesenchymal transition (EMT). In our study, miR-511-5p was downregulated in GC cell lines and tissues, and inversely associated with PAK2. Luciferase reporter assay confirmed that miR-511-5p could bind to PAK2. MiR-511-5p mimics significantly upregulated E-cadherin and downregulated N-cadherin, Vimentin and Snail, and consequently inhibited cell migration and invasion. However, reintroduction of PAK2 reversed the inhibitory function of miR-511-5p on BGC-823 and HGC-27 cells. Our research suggested that tumor-suppressive function of miR-511-5p in GC was inhibited by PAK2, and miR-511-5p/PAK2 axis may serve as a new strategy in GC management.

LncRNA SNHG17 regulates cell proliferation and invasion by targeting miR-338-3p/SOX4 axis in esophageal squamous cell carcinoma

Small nucleolar RNA host gene 17 (SNHG17), a novel functional long noncoding RNA, has been demonstrated to play an essential role in the oncogenesis of several tumors. However, for esophageal squamous cell carcinoma (ESCC) the expression pattern and detailed function of SNHG17 are largely unknown. Hence, we conducted this study to explore potential roles and underlying oncogenic mechanisms for SNHG17 in ESCC progression. Results demonstrated SNHG17 to be markedly upregulated in ESCC. Knockdown of SNHG17 significantly suppressed ESCC cell proliferation, invasion, and epithelial-mesenchymal transition in vitro and tumor growth in vivo. Online database software analysis found miR-338-3p to interact with SNHG17 with the level of miR-338-3p negatively correlated with SNHG17 levels in ESCC samples. Further, miR-338-3p was found to directly target SRY-box transcription factor 4 (SOX4) in ESCC cells. Mechanistic analysis suggested that SNHG17 acts as an endogenous "sponge" competing with miR-338-3p to regulate SOX4, thereby promoting tumor progression. These results suggest that these molecular interactions may be potential therapeutic targets for ESCC.

A minor review of microRNA-338 exploring the insights of its function in tumorigenesis

MicroRNAs(miRNAs) are small non-coding RNAs which have a critical role in various biological processes via direct binding and post-transcriptionally regulating targeted genes expression. More than one-half of human genes were regulated by miRNAs and their aberrant expression was detected in various human diseases, including cancers. miRNA-338 is a new identified miRNA and increasing evidence show that miRNA-338 participates in the progression of lots of cancers, such as lung cancer, hepatocellular cancer, breast cancer, glioma, and so on. Although a range of targets and signaling pathways such as MACC1 and Wnt/β-catenin signaling pathway were illustrated to be regulated by miRNA-338, which functions in tumor progression are still ambiguous and the underlying molecular mechanisms are also unclear. Herein, we reviewed the latest studies in miRNA-338 and summarized its roles in different type of human tumors, which might provide us new idea for further investigations and potential targeted therapy.

Molecular interactions of miR-338 during tumor progression and metastasis

Background

Cancer, as one of the main causes of human deaths, is currently a significant global health challenge. Since the majority of cancer-related deaths are associated with late diagnosis, it is necessary to develop minimally invasive early detection markers to manage and reduce mortality rates. MicroRNAs (miRNAs), as highly conserved non-coding RNAs, target the specific mRNAs which are involved in regulation of various fundamental cellular processes such as cell proliferation, death, and signaling pathways. MiRNAs can also be regulated by long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). They are highly stable in body fluids and have tumor-specific expression profiles, which suggest their suitability as efficient non-invasive diagnostic and prognostic tumor markers. Aberrant expression of miR-338 has been widely reported in different cancers. It regulates cell proliferation, migration, angiogenesis, and apoptosis in tumor cells.

Main body

In the present review, we have summarized all miR-338 interactions with other non-coding RNAs (ncRNAs) and associated signaling pathways to clarify the role of miR-338 during tumor progression.

Conclusions

It was concluded that miR-338 mainly functions as a tumor suppressor in different cancers. There were also significant associations between miR-338 and other ncRNAs in tumor cells. Moreover, miR-338 has a pivotal role during tumor progression using the regulation of WNT, MAPK, and PI3K/AKT signaling pathways. This review highlights miR-338 as a pivotal ncRNA in biology of tumor cells.

Prognostic Value of a Four-miRNA Signature in Patients With Lymph Node Positive Locoregional Esophageal Squamous Cell Carcinoma Undergoing Complete Surgical Resection

OBJECTIVE

This study was intended to identify prognostic biomarkers for lymph node (LN)-positive locoregional esophageal squamous cell carcinoma (ESCC) patients.

SUMMARY OF BACKGROUND DATA

Surgery is a major treatment for LN-positive locoregional ESCC patients in China. However, patient outcomes are poor and heterogeneous.

METHODS

ESCC-associated miRNAs were identified by microarray and validated by quantitative real-time polymerase chain reaction analyses in ESCC and normal esophageal epithelial samples. A multi-miRNA based classifier was established using a least absolute shrinkage and selection operator model in a training set of 145 LN-positive locoregional ESCCs, and further assessed in internal testing and independent validation sets of 145 and 243 patients, respectively.

RESULTS

Twenty ESCC-associated miRNAs were identified and validated. A 4-miRNA based classifier (miR-135b-5p, miR-139-5p, miR-29c-5p, and miR-338-3p) was generated to classify LN-positive locoregional ESCC patients into high and low-risk groups. Patients with high-risk scores in the training set had a lower 5-year overall survival rate [8.7%, 95% confidence interval (CI): 0-20.3] than those with low-risk scores (50.3%, 95% CI: 40.0-60.7; P < 0.0001). The prognostic accuracy of the classifier was validated in the internal testing (P < 0.0001) and independent validation sets (P = 0.00073). Multivariate survival analyses showed that the 4-miRNA based classifier was an independent prognostic factor, and the combination of the 4-miRNA based classifier and clinicopathological prognostic factors significantly improved the prognostic accuracy of clinicopathological prognostic factors alone.

CONCLUSION

Our 4-miRNA based classifier is a reliable prognostic prediction tool for overall survival in LN-positive locoregional ESCC patients and might offer a novel probability of ESCC treatment individualization.

hsa_circ_0001018 promotes papillary thyroid cancer by facilitating cell survival, invasion, G1/S cell cycle progression, and repressing cell apoptosis via crosstalk with miR-338-3p and SOX4

We identified a novel interactome, circ_0001018/miR-338-3p/SOX4, in papillary thyroid cancer (PTC), and we intended to confirm the regulatory relationship between the three and to study the effects of the three in PTC. The bioinformatics method was used to screen out the circular RNA and mRNA of interest. A cellular fractionation assay and fluorescence in situ hybridization (FISH) assay were conducted to prove that circ_0001018 and CCT4 (the host gene of circ_0001018) mRNA primarily localized in the cytoplasm of PTC cell lines. By qRT-PCR analysis, the expression of circ_0001018 and SOX4 mRNA was found upregulated while the expression of miR-338-3p was found downregulated in PTC tissues and cells. circ_0001018 silence significantly inhibited the tumor growth in xenografted nude mice. A series of cytological experiments such as a Cell Counting Kit-8 (CCK-8) assay, a 5-ethynyl-2′-deoxyuridine (EdU) assay, cell cycle profiling, wound healing, a transwell assay, and cell apoptosis were conducted and showed that circ_0001018 and SOX4 promoted cell proliferation, migration, and invasion, inhibited cell apoptosis, and reduced the cell cycle arrest at the G₁ phase in PTC cells. Compared with circ_0001018 and SOX4, miR-338-3p held the opposite function. The regulatory relationship between circ_0001018 and miR-338-3p, and between miR-338-3p and SOX4 mRNA, was validated using a luciferase reporter gene assay and/or RNA immunoprecipitation (RIP assay). Our findings showed that circ_0001018 acted as the tumor promoter via sponging miR-338-3p to elevate SOX4 expression level in PTC. Importantly, this novel circ_0001018/miR-338-3p/SOX4 axis has the potential to be considered as a therapy target for PTC.

The role of microRNA-338-3p in cancer: growth, invasion, chemoresistance, and mediators

Cancer still remains as one of the leading causes of death worldwide. Metastasis and proliferation are abnormally increased in cancer cells that subsequently, mediate resistance of cancer cells to different therapies such as radio-, chemo- and immune-therapy. MicroRNAs (miRNAs) are endogenous short non-coding RNAs that can regulate expression of target genes at post-transcriptional level and capable of interaction with mRNA-coding genes. Vital biological mechanisms including apoptosis, migration and differentiation are modulated by these small molecules. MiRNAs are key players in regulating cancer proliferation and metastasis as well as cancer therapy response. MiRNAs can function as both tumor-suppressing and tumor-promoting factors. In the present review, regulatory impact of miRNA-338-3p on cancer growth and migration is discussed. This new emerging miRNA can regulate response of cancer cells to chemotherapy and radiotherapy. It seems that miRNA-338-3p has dual role in cancer chemotherapy, acting as tumor-promoting or tumor-suppressor factor. Experiments reveal anti-tumor activity of miRNA-338-3p in cancer. Hence, increasing miRNA-338-3p expression is of importance in effective cancer therapy. Long non-coding RNAs, circular RNAs and hypoxia are potential upstream mediators of miRNA-338-3p in cancer. Anti-tumor agents including baicalin and arbutin can promote expression of miRNA-338-3p in suppressing cancer progression. These topics are discussed to shed some light on function of miRNA-338-3p in cancer cells.

Hypoxia-inhibited miR-338-3p suppresses breast cancer progression by directly targeting ZEB2

Hypoxia plays an essential role in the development of various cancers. The biological function and underlying mechanism of microRNA-338-3p (miR-338-3p) under hypoxia remain unclarified in breast cancer (BC). Herein, we performed bioinformatics, gain and loss of function of miR-338-3p, a luciferase reporter assay, and chromatin immunoprecipitation (ChIP) in vitro and in a tumor xenograft model. We also explored the potential signaling pathways of miR-338-3p in BC. We detected the expression levels and prognostic significance of miR-338-3p in BC by qRT-PCR and in situ hybridization. MiR-338-3p was lowly expressed in BC tissues and cell lines, and BC patients with underexpression of miR-338-3p tend to have a dismal overall survival. Functional experiments showed that miR-338-3p overexpression inhibited BC cell proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) process, whereas miR-338-3p silencing abolished these biological behaviors. Zinc finger E-box-binding homeobox 2 (ZEB2) was validated as a direct target of miR-338-3p. ZEB2 overexpression promoted while ZEB2 knockdown abolished the promoted effects of miR-338-3p knockdown on cell biological behaviors through the NF-ĸB and PI3K/Akt signal pathways. HIF1A can transcriptionally downregulate miR-338-3p under hypoxia. In total, miR-338-3p counteracts hypoxia-induced BC cells growth, migration, invasion, and EMT via the ZEB2 and NF-ĸB/PI3K signal pathways, implicating miR-338-3p may be a promising target to treat patients with BC.

Competing Endogenous RNA Networks in the Epithelial to Mesenchymal Transition in Diffuse-Type of Gastric Cancer

Simple Summary

The diffuse-type of gastric cancer is associated with epithelial to mesenchymal transition. Loss of E-cadherin expression is the hallmark of this process and is largely due to the upregulation of the transcription factors ZEB1/2, Snail, Slug, and Twist1/2. However, miRNA and lncRNAs can also participate through these transcription factors which directly target E-cadherin. The competing endogenous RNA (ceRNA) network hypothesis state that lncRNA can sponge the miRNA pool that targets these transcripts. Based on the lack of said networks in the epithelial to mesenchymal transition, we performed a prediction analysis that resulted in novel ceRNA networks which will expand our knowledge of the molecular basis of the diffuse-type of gastric cancer.

Abstract

The diffuse-type of gastric cancer (DGC), molecularly associated with epithelial to mesenchymal transition (EMT), is increasing in incidence. Loss of E-cadherin expression is the hallmark of the EMT process and is largely due to the upregulation of the EMT-inducing transcription factors ZEB1/2, Snail, Slug, and Twist1/2. However, ncRNA, such as miRNA and lncRNAs, can also participate in the EMT process through the direct targeting of E-cadherin and other EMT-inducing transcription factors. Additionally, lncRNA can sponge the miRNA pool that targets these transcripts through competing endogenous RNA (ceRNA) networks. In this review, we focus on the role of ncRNA in the direct deregulation of E-cadherin, as well as EMT-inducing transcription factors. Based on the relevance of the ceRNA network hypothesis, and the lack of said networks in EMT, we performed a prediction analysis for all miRNAs and lncRNAs that target E-cadherin, as well as EMT-inducing transcription factors. This analysis resulted in novel predicted ceRNA networks for E-cadherin and EMT-inducing transcription factors (EMT-TFs), as well as the expansion of the molecular basis of the DGC.

Circular RNA circCCDC66 Contributes to Malignant Phenotype of Osteosarcoma by Sponging miR-338-3p to Upregulate the Expression of PTP1B

In recent years, the mechanism of cancer research has become hotspots of life science and medicine, especially due to the rapid development of molecular medicine and bioinformatics research. Similarly, the molecular mechanism also has received increasing attention in osteosarcoma (OS) research. Also, a considerable amount of research confirmed that circular RNAs (circRNAs) could regulate cancer cell growth and metastasis. This study aimed to explore the effect of a circRNA, circCCDC66, on OS and reveal its potential molecular mechanism. High circCCDC66 expression level was found in OS patient-derived tissue samples and OS cell lines by qRT-PCR. The abilities cell proliferation and metastatic of U2OS and SW1353 cells were then assessed by Cell Counting Kit-8 and transwell assay, respectively. The interaction between circCCDC66 and its target miRNAs were verified by the dual-luciferase reporter assay. Through functional experiments, we found that circCCDC66 knockdown promoted the inhibition of cell proliferation and metastatic of OS cell lines. From mechanistic perspective, circCCDC66 upregulated PTP1B by sponging miR-338-3p. Collectively, our findings demonstrated that circCCDC66 contributed to malignant behaviors of OS cells by miR-338-3p/PTP1B pathway, which suggested circCCDC66/miR-338-3p/PTP1B axis might be a potential therapeutic target.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

Reactivation of microRNA-506 inhibits gastric carcinoma cell metastasis through ZEB2

MicroRNAs (miRNAs) are frequently dysregulated in a variety of human cancers, including gastric carcinoma. To improve our understanding of the role of miRNAs in gastric carcinoma and potential identify novel biomarkers or therapeutic agents, we performed microarray analysis to identify differentially expressed miRNAs in gastric carcinoma, compared with paired non-cancerous gastric tissues. We identified significantly differentially expressed miRNAs in gastric carcinoma tissues, including miR-506. We validated the microarray results by quantitative reverse transcription polymerase chain reaction in 26 specimens and confirmed significant downregulation of miR-506 in gastric carcinoma. Bioinformatics analysis predicted ZEB2 (zinc finger E-box-binding homeobox 2) as a potential target of miR-506. MiR-506 levels and ZEB2 levels were inversely correlated in gastric carcinoma, and low miR-506 levels in gastric carcinoma were associated with poor prognosis. Overexpression of miR-506 in gastric carcinoma cells significantly inhibited cell migration and invasion, while depletion of miR-506 in gastric carcinoma cells significantly increased cell migration and invasion. Transplantation of miR-506-overexpressing gastric carcinoma cells developed significantly smaller tumor, compared to the control. Thus, our results suggest that miR-506 may function as a tumor suppressor and targets and inhibits ZEB2 in gastric carcinoma.

Circular RNA hsa_circ_0000326 acts as a miR-338-3p sponge to facilitate lung adenocarcinoma progression

Background

Circular RNAs (circRNAs) are a novel class of noncoding RNAs that regulate gene expression at the transcriptional or posttranscriptional level. According to recent studies, circRNAs are involved in the pathogenesis of cancer, but the roles of circRNAs in lung adenocarcinoma are largely unknown.

Methods

In this study, we identified a novel upregulated circRNA, hsa_circ_0000326, in human lung adenocarcinoma tissues using microarray analysis and qRT-PCR. We then explored the biological role of hsa_circ_0000326 using gain- and loss-of-function assays in adenocarcinoma cells. Bioinformatics databases were used to screen for potential target miRNAs and the luciferase reporter assays and RNA-FISH further validated the interaction. Downstream protein was detected by western blot. Finally, we established xenografts in nude mice to assess the function of hsa_circ_0000326 in vivo.

Results

We found that high expression of hsa_circ_0000326 was correlated with tumor size, regional lymph node status and differentiation in human lung adenocarcinoma. Additionally, we conducted gain- and loss-of-function assays and found that hsa_circ_0000326 acted as a positive regulator of cell proliferation and migration and a negative regulator of apoptosis. Mechanistic studies showed that hsa_circ_0000326 acted as a miR-338-3p sponge and altered the function of miR-338-3p, which in turn upregulated the expression of the downstream target RAB14 and affected the proliferation, migration and apoptosis of lung adenocarcinoma cells.

Conclusions

Collectively, our study results reveal crucial roles for hsa_circ_0000326 in the proliferation, migration and apoptosis of lung adenocarcinoma cells and suggest that hsa_circ_0000326 may represent a potential therapeutic target in patients with lung adenocarcinoma.

Chidamide Inhibits Glioma Cells by Increasing Oxidative Stress via the miRNA-338-5p Regulation of Hedgehog Signaling

Objective

Chidamide has a broad spectrum of antitumor activity but its function on glioma remains unknown. The increase of reactive oxygen species (ROS) and reactive nitrogen species (RNS) may control glioma risk by promoting its apoptosis and necrosis. Hedgehog pathway is crucial to glioma cell proliferation and controls ROS production. We aimed to explore the effects of chidamide on the levels of miR-338-5p (glioma cell inhibitor), which may regulate Hedgehog signaling, resulting in the changes of RNS. Materials and Methods. Migration and invasion activities of glioma cells were measured by using the Transwell chamber assay. The expression levels of Sonic Hedgehog (Shh), Indian Hedgehog (Ihh), Desert Hedgehog (Dhh), miR-338-5p, and related molecules were detected by using real-time PCR (RT-PCR) and or Western Blot in U87 and HS683 glioma cells. The effects of chidamide on these molecules were measured by using the miR-338-5p inhibitor or mimics in U87 and HS683 glioma cell lines. ROS and RNS were measured by DCF DA and DAF-FM DA fluorescence. Biomarkers of oxidative stress were measured by using a corresponding kit. Apoptosis and necrosis rates were measured by using flow cytometry.

Results

Chidamide inhibited the growth rate, migration, and invasion of human malignant glioma cells and increased the level of miR-338-5p. miR-338-5p inhibitor or mimics increased or inhibited the growth rate of U87 and HS683 glioma cells. Chidamide inhibited the levels of Shh, Ihh, migration protein E-cadherin, and invading protein MMP-2. The increase in the level of Shh and Ihh led to the reduction in the ROS and RNS levels. miR-338-5p inhibitor or mimics also showed a promoting or inhibitory function for the levels of Shh and Ihh. Furthermore, miR-338-5p mimics and inhibitor inhibited or promoted the migration and invasion of the glioma cells (P < 0.05). Evaluated levels of miR-338-5p increased oxidative stress level and apoptosis and necrosis rate by regulating the levels of biomarkers of oxidative stress (P < 0.05). Evaluated levels of miR-338-5p increased oxidative stress level and apoptosis and necrosis rate by regulating the levels of biomarkers of oxidative stress (

Conclusion

Chidamide inhibits glioma cells by increasing oxidative stress via the miRNA-338-5p regulation of Hedgehog signaling. Chidamide may be a potential drug in the prevention of glioma development.

MicroRNAs and Long Non-coding RNAs in c-Met-Regulated Cancers

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are components of many signaling pathways associated with tumor aggressiveness and cancer metastasis. Some lncRNAs are classified as competitive endogenous RNAs (ceRNAs) that bind to specific miRNAs to prevent interaction with target mRNAs. Studies have shown that the hepatocyte growth factor/mesenchymal-epithelial transition factor (HGF/c-Met) pathway is involved in physiological and pathological processes such as cell growth, angiogenesis, and embryogenesis. Overexpression of c-Met can lead to sustained activation of downstream signals, resulting in carcinogenesis, metastasis, and resistance to targeted therapies. In this review, we evaluated the effects of anti-oncogenic and oncogenic non-coding RNAs (ncRNAs) on c-Met, and the interactions among lncRNAs, miRNAs, and c-Met in cancer using clinical and tissue chromatin immunoprecipition (ChIP) analysis data. We summarized current knowledge of the mechanisms and effects of the lncRNAs/miR-34a/c-Met axis in various tumor types, and evaluated the potential therapeutic value of lncRNAs and/or miRNAs targeted to c-Met on drug-resistance. Furthermore, we discussed the functions of lncRNAs and miRNAs in c-Met-related carcinogenesis and potential therapeutic strategies.

The crucial role of ZEB2: From development to epithelial-to-mesenchymal transition and cancer complexity

Zinc finger E-box binding homeobox 2 (ZEB2) is a DNA-binding transcription factor, which is mainly involved in epithelial-to-mesenchymal transition (EMT). EMT is a conserved process during which mature and adherent epithelial-like state is converted into a mobile mesenchymal state. Emerging data indicate that ZEB2 plays a pivotal role in EMT-induced processes such as development, differentiation, and malignant mechanisms, for example, drug resistance, cancer stem cell-like traits, apoptosis, survival, cell cycle arrest, tumor recurrence, and metastasis. In this regard, the understanding of mentioned subjects in the development of normal and cancerous cells could be helpful in cancer complexity of diagnosis and therapy. In this study, we review recent findings about the biological properties of ZEB2 in healthy and cancerous states to find new approaches for cancer treatment.

Decoding and targeting the molecular basis of MACC1-driven metastatic spread: Lessons from big data mining and clinical-experimental approaches

Metastasis remains the key issue impacting cancer patient survival and failure or success of cancer therapies. Metastatic spread is a complex process including dissemination of single cells or collective cell migration, penetration of the blood or lymphatic vessels and seeding at a distant organ site. Hundreds of genes involved in metastasis have been identified in studies across numerous cancer types. Here, we analyzed how the metastasis-associated gene MACC1 cooperates with other genes in metastatic spread and how these coactions could be exploited by combination therapies: We performed (i) a MACC1 correlation analysis across 33 cancer types in the mRNA expression data of TCGA and (ii) a comprehensive literature search on reported MACC1 combinations and regulation mechanisms. The key genes MET, HGF and MMP7 reported together with MACC1 showed significant positive correlations with MACC1 in more than half of the cancer types included in the big data analysis. However, ten other genes also reported together with MACC1 in the literature showed significant positive correlations with MACC1 in only a minority of 5 to 15 cancer types. To uncover transcriptional regulation mechanisms that are activated simultaneously with MACC1, we isolated pan-cancer consensus lists of 1306 positively and 590 negatively MACC1-correlating genes from the TCGA data and analyzed each of these lists for sharing transcription factor binding motifs in the promotor region. In these lists, binding sites for the transcription factors TELF1, ETS2, ETV4, TEAD1, FOXO4, NFE2L1, ELK1, SP1 and NFE2L2 were significantly enriched, but none of them except SP1 was reported in combination with MACC1 in the literature. Thus, while some of the results of the big data analysis were in line with the reported experimental results, hypotheses on new genes involved in MACC1-driven metastasis formation could be generated and warrant experimental validation. Furthermore, the results of the big data analysis can help to prioritize cancer types for experimental studies and testing of combination therapies.

MicroRNA-338-3p suppresses cell proliferation, migration and invasion in human malignant melanoma by targeting MACC1

Malignant melanoma (MM) is the most aggressive form of skin cancer originating from melanocytes with increased proliferative and metastatic ability. Previous studies have revealed that microRNA-338-3p (miR-338-3p) functions as a tumor suppressor in several types of cancer, including cervical cancer, renal cell carcinoma and thyroid cancer. However, the function and mechanism underlying the action of miR-383-3p in MM remain unclear. In the study, aberrant downregulation of miR-338-3p was observed in 60 pairs of MM and adjacent non-tumor tissue using quantitative polymerase chain reaction assay. Decreased miR-383-3p expression was associated with advanced clinical stage (P<0.05) and lymph node metastasis (P<0.001). The overexpression of miR-338-3p in A375 and G361 cells suppressed cell proliferation and migration using MTT, colony formation, wound healing and transwell assays. Mechanistically, MACC1 was identified as a direct target for miR-338-3p using bioinformatics prediction and dual-luciferase assays. Furthermore, MACC1 expression was significantly increased and inversely correlated with the levels of miR-338-3p in MM tissues. More importantly, restoration of MACC1 resulted in reversed the inhibitory effects of miR-338-3p overexpression on MM cells by altering the expression levels of PCNA and epithelial-mesenchymal transition (EMT)-associated proteins. These results suggest that miR-338-3p functions as a novel tumor suppressor, at least in part, via targeting MACC1 and suggest that miR-338-3p may serve as a potential target for treatment of MM patients.

Roles of E-cadherin and Noncoding RNAs in the Epithelial-mesenchymal Transition and Progression in Gastric Cancer

The epithelial–mesenchymal transition (EMT) is thought to be at the root of invasive and metastatic cancer cell spreading. E-cadherin is an important player in this process, which forms the structures that establish and maintain cell–cell interactions. A partial or complete loss of E-cadherin expression in the EMT is presumably mediated by mechanisms that block the expression of E-cadherin regulators and involve the E-cadherin-associated transcription factors. The protein is involved in several oncogenic signaling pathways, such as the Wnt/β-catenin, Rho GTPase, and EGF/EGFR, whereby it plays a role in many tumors, including gastric cancer. Such noncoding transcripts as microRNAs and long noncoding RNAs—critical components of epigenetic control of gene expression in carcinogenesis—contribute to regulation of the E-cadherin function by acting directly or through numerous factors controlling transcription of its gene, and thus affecting not only cancer cell proliferation and metastasis, but also the EMT. This review focuses on the role of E-cadherin and the non-coding RNAs-mediated mechanisms of its expressional control in the EMT during stomach carcinogenesis.

MACC1-the first decade of a key metastasis molecule from gene discovery to clinical translation

Deciphering the paths to metastasis and identifying key molecules driving this process is one important issue for understanding and treatment of cancer. Such a key driver molecule is Metastasis Associated in Colon Cancer 1 (MACC1). A decade long research on this evolutionarily conserved molecule with features of a transcription factor as well as an adapter protein for versatile protein-protein interactions has shown that it has manifold properties driving tumors to their metastatic stage. MACC1 transcriptionally regulates genes involved in epithelial-mesenchymal transition (EMT), including those which are able to directly induce metastasis like c-MET, impacts tumor cell migration and invasion, and induces metastasis in solid cancers. MACC1 has proven as a valuable biomarker for prognosis of metastasis formation linked to patient survival and gives promise to also act as a predictive marker for individualized therapies in a broad variety of cancers. This review discusses the many features of MACC1 in the context of the hallmarks of cancer and the potential of this molecule as biomarker and novel therapeutic target for restriction and prevention of metastasis.

Clinicopathological and prognostic significance of metastasis-associated in colon cancer-1 in gastric cancer: A meta-analysis

Background:

The gene metastasis-associated in colon cancer-1 (MACC1) has been reported to be overexpressed in diverse human malignancies, and an increasing amount of evidence suggests that its overexpression is associated with the development and progression of many human tumors. However, the prognostic and clinicopathological value of MACC1 in gastric cancer remains inconclusive. Therefore, we conducted this meta-analysis to investigate the effect of positive MACC1 expression on clinicopathological features and survival outcomes in gastric cancer.

Methods:

Medline, Web of Science, and EMBASE databases were searched for relevant articles published up to 10 April 2018. The correlation of MACC1 expression levels with overall survival and clinicopathological features was analyzed.

Results:

In this meta-analysis, nine studies with a total of 2103 gastric cancer patients were included. Our results showed that high expression of MACC1 was significantly related to a poor overall survival. Moreover, our meta-analysis showed that MACC1 overexpression was significantly linked to distant metastasis and vascular invasion. There were no significant correlations between positive MACC1 expression and gender, localization, tumor-node-metastasis (TNM) stage, tumor extent (T stage) and lymph node involvement (N stage)

Conclusions:

MACC1 expression levels can serve as a novel prognostic factor in gastric cancer patients.

Down-regulation of miR-338-3p and Up-regulation of MACC1 Indicated Poor Prognosis of Epithelial Ovarian Cancer Patients

Objective To detect the expression of microRNA-338-3p (miR-338-3p) and MET transcriptional regulator MACC1 (MACC1) gene in different ovarian tissues, to analyze their relationships, their correlations to the clinicopathologic characteristics of epithelial ovarian cancer and their significant to the progression of ovarian cancer. Methods The expression of miR-338-3p and MACC1 gene in 20 specimens of normal ovarian tissues, 20 specimens of benign epithelial ovarian tumor and 65 specimens of epithelial ovarian cancer was detected by real-time PCR method. Their interrelationships and their correlations to the clinicopathologic characteristics of epithelial ovarian cancer were analyzed. Risk factors of recurrence and death were discussed by binary Logistic regression analysis. The relations between miR-338-3p and MACC1 expression and the survival of ovarian cancer were measured by Kaplan-Meier analysis. Results The expressions of miR-338-3p and MACC1 gene in epithelial ovarian cancer tissues were (0.331±0.038) and (0.774±0.025), significant differences were noted between epithelial ovarian cancer and normal ovarian tissues, benign ovarian tumors (F=77.916, P=1.205E-18; F=77.945, P=1.187E-18). In different ovarian tissues, miR-338-3p expression was negatively correlated to MACC1 expression (r = -0.968, P<0.0001). In epithelial ovarian cancer, lower expression of miR-338-3p and higher expression of MACC1 were associated with more advanced FIGO stage, higher histological grade and developed lymph node metastasis. Down-regulation of miR-338-3p was related with the recurrence (P=0. 005, OR=12.862, 95%CI: 2.120~78.026) and death (P=0. 007, OR=12.837, 95%CI: 2.205~81.389) of ovarian cancer patients, which was showed by binary Logistic regression analysis. Compared to other patients, the overall survival rate and progression free survival rate of patients with lower miR-338-3p and higher MACC1 expression were obviously poorer (χ²=16.955, P=7.219E-5; χ²=18.929, P=2.828E-5). Conclusions Down-regulation of miR-338-3p and up-regulation of MACC1 gene were closely related with the poor prognosis of epithelial ovarian cancer patients, which could served as bio-markers of the progression and recurrence of ovarian cancer.

miR-338-3p regulates the proliferation, apoptosis and migration of SW480 cells by targeting MACC1

The mortality and incidence rates of colorectal cancer (CRC) vary widely worldwide. miR-338-3p inhibits tumor cell proliferation in several types of cancer, however, the role of miR-338-3p on CRC remains unknown. The aim of the current study was to investigate the cellular function of miRNA-338-3p (miR-338-3p) in CRC, the malignant behavior of CRC cells and the interaction between miR-338-3p and metastasis-associated in colon cancer-1 (MACC1). miR-338-3p expression was significantly decreased in CRC tissue compared with adjacent normal tissue. In the CRC cell line SW480, miR-338-3p overexpression suppressed cell proliferation and migration and induced G1/S cell cycle arrest and apoptosis. By contrast, miR-338-3p knockdown significantly enhanced cell proliferation and migration, and suppressed G1/S cell cycle arrest and apoptosis. Furthermore, the dual-luciferase reporter assay confirmed MACC1 as a direct target of miR-338-3p. In addition, miR-338-3p overexpression reduced the level of MACC1 protein expression and MACC1 expression was significantly upregulated in CRC tissue samples. MACC1 siRNA significantly reduced CRC cell proliferation and migration, whilst cell apoptosis was significantly increased. In conclusion, miR-338-3p expression was decreased in CRC. miR-338-3p regulated the proliferation, apoptosis and migration of CRC cells by targeting MACC1.

miR-577 Regulates TGF-β Induced Cancer Progression through a SDPR-Modulated Positive-Feedback Loop with ERK-NF-κB in Gastric Cancer

Transforming growth factor β (TGF-β) drives epithelial-mesenchymal transition (EMT), playing vital roles in cancer metastasis. The crosstalk between microRNAs (miRNAs) and TGF-β are frequently observed and involved in TGF-β-induced EMT. Here, we determine that miR-577 is significantly upregulated in gastric cancer (GC). miR-577 expression is positively correlated with GC metastasis status and poor patient prognosis. Functional assays demonstrate that miR-577 promotes metastasis and chemoresistance by inducing EMT and stemness-like properties. Moreover, TGF-β promotes the expression of miR-577, and miR-577 participates TGF-β-mediated cancer metastasis. Mechanistically, TGF-β activates miR-577 via NF-κB-mediated transcription, and miR-577 enhances TGF-β signaling by targeting the serum deprivation protein response (SDPR), which directly interacts with ERK to inactivate the ERK-NF-κB pathway, hence forming a feedback loop to drive tumor metastasis. A plausible mechanism of EMT induction by the TGF-β network is elucidated. Our findings suggest that the TGF-β-miR-577-SDPR axis may be a potential prognostic marker and therapeutic target against cancer metastasis in GC.

Epigenetic Silencing of miRNA-338-5p and miRNA-421 Drives SPINK1-Positive Prostate Cancer

PURPOSE

Serine peptidase inhibitor, Kazal type-1 (SPINK1) overexpression defines the second most recurrent and aggressive prostate cancer subtype. However, the underlying molecular mechanism and pathobiology of SPINK1 in prostate cancer remains largely unknown.

EXPERIMENTAL DESIGN

miRNA prediction tools were employed to examine the SPINK1-3'UTR for miRNA binding. Luciferase reporter assays were performed to confirm the SPINK1-3'UTR binding of shortlisted miR-338-5p/miR-421. Furthermore, miR-338-5p/-421-overexpressing cancer cells (SPINK1-positive) were evaluated for oncogenic properties using cell-based functional assays and a mouse xenograft model. Global gene expression profiling was performed to unravel the biological pathways altered by miR-338-5p/-421. IHC and RNA in situ hybridization were carried out on prostate cancer patients' tissue microarray for SPINK1 and EZH2 expression, respectively. Chromatin immunoprecipitation assay was performed to examine EZH2 occupancy on the miR-338-5p/-421-regulatory regions. Bisulfite sequencing and methylated DNA immunoprecipitation were performed on prostate cancer cell lines and patients' specimens.

RESULTS

We established a critical role of miRNA-338-5p/-421 in posttranscriptional regulation of SPINK1. Ectopic expression of miRNA-338-5p/-421 in SPINK1-positive cells abrogates oncogenic properties including cell-cycle progression, stemness, and drug resistance, and shows reduced tumor burden and distant metastases in a mouse model. Importantly, we show that patients with SPINK1-positive prostate cancer exhibit increased EZH2 expression, suggesting its role in epigenetic silencing of miRNA-338-5p/-421. Furthermore, presence of CpG dinucleotide DNA methylation marks on the regulatory regions of miR-338-5p/-421 in SPINK1-positive prostate cancer cells and patients' specimens confirms epigenetic silencing.

CONCLUSIONS

Our findings revealed that miRNA-338-5p/-421 are epigenetically silenced in SPINK1-positive prostate cancer, although restoring the expression of these miRNAs using epigenetic drugs or synthetic mimics could abrogate SPINK1-mediated oncogenesis.See related commentary by Bjartell, p. 2679.

MicroRNA-338-3p inhibits tumor growth and metastasis in osteosarcoma cells by targeting RUNX2/CDK4 and inhibition of MAPK pathway

Osteosarcoma (OS) is one of the most aggressive bone tumors. MicroRNAs (miRNAs) have been found to implicate in the pathogenesis of different types of cancers, including OS. This study aimed to explore the roles of miR-338-3p in OS and investigate the underlying mechanism. Human OS cell lines (MG-63 and U2OS) and osteoblast (hFOB) cell line were used in the study. The expression levels of miR-338-3p, runt-related transcription factor 2 (RUNX2) and cyclin-dependent kinase 4 (CDK4) were altered by transient transfection and determined by quantitative real-time polymerase chain reaction/Western blot analysis. Cell viability, colony numbers, migration, and invasion, and apoptotic cells were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay, transwell assay, and flow cytometry assay, respectively. Dual luciferase reporter assay was performed to identify the target gene of miR-338-3p. Western blot assay was carried to measure the protein expression levels involved in cell apoptosis, migration, and mitogen-activated protein kinases (MAPK) pathway. We found that the expression of miR-338-3p was downregulated in MG-63 cell and U2OS cells, compared with hFOB cells. MiR-338-3p suppression significantly increased cell viability and colony numbers, promoted cell migration, and invasion, but suppressed cell apoptosis in MG-63 and U2OS cells. Opposite results were observed in the miR-338-3p overexpression. Interestingly, RUNX2 and CDK4 were direct target genes of miR-338-3p. RUNX2 inhibition shared a similar effect of miR-338-3p mimic on MG-63 cells. Furthermore, miR-338-3p inhibited the activation of MAPK pathway in MG-63 cells. To conclude, these findings suggested that miR-338-3p functioned as a tumor suppressor in OS cells by targeting RUNX2 and CDK4, as well as inhibition of the MAPK pathway.

LncRNA XLOC_006390 facilitates cervical cancer tumorigenesis and metastasis as a ceRNA against miR-331-3p and miR-338-3p

OBJECTIVE

Cervical cancer is one of the most common malignant tumors. Our previous results showed that long non-coding RNA (lncRNA) XLOC_006390 plays an important role in cervical cancer. In this study, we have explored the mechanism of action of lncRNA XLOC_006390.

METHODS

LncRNA XLOC_006390 was proposed to exercise its function as a competing endogenous RNA (ceRNA), and its potential targeted miRNAs was predicted through the database LncBase Predicted v.2. Two miRNAs, miR-331-3p, and miR-338-3p, were chosen for the study. Expression of miRNAs and lncRNA in cervical cancer cells and tissues was detected by reverse transcription polymerase chain reaction. To determine the correlation, silencing of XLOC_006390, over-expression of miR-331-3p, and miR-338-3p was performed in SiHa and Caski cell lines, respectively.

RESULTS

Based on the interactive effect between miRNA and lncRNA, miR-331-3p and miR-338-3p were significantly downregulated in cervical cancer cells and tissues, and their expression levels were negatively related to that of lncRNA. Our results also showed that the expression of miR-331-3p target gene NRP2, miR-338-3p target genes PKM2, EYA2 was significantly downregulated when the XLOC_006390 was knocked down. Further, XLOC_006390 was found to facilitate cervical cancer tumorigenesis and metastasis by downregulating miR-331-3p and miR-338-3p expression.

CONCLUSION

Taken together, our study demonstrated that XLOC_006390 may serve as a ceRNA and reversely regulates the expression of miR-331-3p and miR-338-3p, thus facilitating cervical cancer tumorigenesis and metastasis.

Current Targeted Therapies in HER2-Positive Gastric Adenocarcinoma

Gastric cancer is one of the most common types of cancer in the world, usually diagnosed at an advanced stage. Despite the advances in specific anticancer agents' development, the survival rates remain modest, even in early stages. In 15%-20% of cases, the human epidermal growth factor receptor 2 (HER2) overexpression was identified. We conducted a general review to summarize the progress that has been made in the targeted treatment of HER2-positive esogastric junction or gastric adenocarcinoma. According to our findings, trastuzumab is the only validated anti-HER2 agent in locally advanced or metastatic disease and its adjuvant effectiveness is assessed in a RTOG phase III study. In a previously treated advanced disease, the maytansine derivate TDM 1 failed to be approved as a second-line regimen, and the tyrosine kinase inhibitor, lapatinib, shows modest results. The antiangiogenics have not been analyzed in specific populations and targeting the mesenchymal-epithelial transition factor (MET) receptor, overexpressed in up to 46% of the advanced disease, seems encouraging. Regarding the checkpoint inhibitors, based on KEYNOTE 059 multilevel ongoing trial, stratified according to the HER2 and programmed death-ligand (PD-L) 1 status, pembrolizumab was approved for third-line treatment of gastric or gastroesophageal junction adenocarcinoma.

Cisplatin resistance in lung cancer is mediated by MACC1 expression through PI3K/AKT signaling pathway activation

One of the major obstacles hindering the treatment of lung cancer (LC) is chemoresistance; however, its mechanism remains unclear. The overexpression of the metastasis-associated in colon cancer 1 (MACC1) gene has been demonstrated to reverse chemoresistance. In the current study, the expression of MACC1 in LC cells with cisplatin resistance (Cis-Re) was investigated. Cisplatin-resistant cell sublines (A549/CR and H446/CR) were induced by stepwise escalation of cisplatin exposure. MTS and flow cytometry assays were performed to measure cell proliferation and apoptosis, respectively. Western blot analysis and qRT-PCR assays were performed to determine the changes in signaling pathway-related protein and mRNA levels, respectively. A nude mouse xenograft model was used for in vivo experiments. Our results showed that MACC1 expression was increased in the cisplatin-resistant A549/CR and H446/CR cell lines, and the resistance was reversed with a decrease of MACC1 expression. MACC1 overexpression triggered an increase of Cis-Re, which was contrary to the effect of MACC1 down-regulation. In addition, the effect of MACC1 on Cis-Re was blocked by the inhibition of the PI3K/AKT pathway, and treatment with both cisplatin and a PI3K/AKT inhibitor effectively inhibited tumor growth in xenografts with MACC1 overexpression. In conclusion, our results revealed that MACC1 increased Cis-Re partially via the PI3K/AKT signaling pathway, suggesting that MACC1 could serve as a potential target to overcome Cis-Re. Furthermore, combination therapy could alleviate Cis-Re resulted from MACC1 overexpression in patients with LC.

MicroRNA‑485 targets MACC1 and inhibits cervical cancer cell proliferation and invasion

A large body of evidence has indicated that microRNAs (miRNAs/miRs) have essential roles in the development and progression of cervical cancer. Thus, miRNAs with dysregulated expression are potential biomarkers for cervical cancer diagnosis and prognosis. In the present study, expression levels of miR‑485 were detected in cervical cancer tissues and cell lines. The effects of miR‑485 overexpression on the proliferation and invasion of cervical cancer cells were determined with Cell Counting kit‑8 and Transwell invasion assays. The mechanisms underlying the action of miR‑485 in cervical cancer were investigated using bioinformatics analysis, a luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis. In addition, the association between miR‑485 and metastasis associated in colon cancer‑1 (MACC1) in cervical cancer tissues was examined. The present study demonstrated that miR‑485 expression was significantly downregulated in cervical cancer tissues and cell lines. Reduced miR‑485 expression in patients with cervical cancer was correlated with International Federation of Gynecology and Obstetrics stage and lymph node metastasis. Furthermore, restored expression of miR‑485 significantly reduced cervical cancer cell proliferation and invasion. MACC1 was identified as a direct target gene of miR‑485 in cervical cancer. MACC1 expression was significantly upregulated in cervical cancer specimens and was inversely correlated with miR‑485 expression. Additionally, the restored expression of MACC1 eliminated the suppressive effects of miR‑485 overexpression on the proliferation and invasion of cervical cancer cells. Notably, the upregulation of miR‑485 suppressed the MET proto‑oncogene, receptor tyrosine kinase (Met)/RAC‑α serine/threonine‑protein kinase (AKT) signaling pathway. These results demonstrated that miR‑485 may perform its tumor suppressive function in cervical cancer by directly targeting MACC1 and inhibiting the Met/AKT signaling pathway. Therefore, the miR‑485/MACC1 axis may be a novel and effective therapeutic target in cervical cancer.

Functional Role of Non-Coding RNAs during Epithelial-To-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is a key biological process involved in a multitude of developmental and pathological events. It is characterized by the progressive loss of cell-to-cell contacts and actin cytoskeletal rearrangements, leading to filopodia formation and the progressive up-regulation of a mesenchymal gene expression pattern enabling cell migration. Epithelial-to-mesenchymal transition is already observed in early embryonic stages such as gastrulation, when the epiblast undergoes an EMT process and therefore leads to the formation of the third embryonic layer, the mesoderm. Epithelial-to-mesenchymal transition is pivotal in multiple embryonic processes, such as for example during cardiovascular system development, as valve primordia are formed and the cardiac jelly is progressively invaded by endocardium-derived mesenchyme or as the external cardiac cell layer is established, i.e., the epicardium and cells detached migrate into the embryonic myocardial to form the cardiac fibrous skeleton and the coronary vasculature. Strikingly, the most important biological event in which EMT is pivotal is cancer development and metastasis. Over the last years, understanding of the transcriptional regulatory networks involved in EMT has greatly advanced. Several transcriptional factors such as Snail, Slug, Twist, Zeb1 and Zeb2 have been reported to play fundamental roles in EMT, leading in most cases to transcriptional repression of cell⁻cell interacting proteins such as ZO-1 and cadherins and activation of cytoskeletal markers such as vimentin. In recent years, a fundamental role for non-coding RNAs, particularly microRNAs and more recently long non-coding RNAs, has been identified in normal tissue development and homeostasis as well as in several oncogenic processes. In this study, we will provide a state-of-the-art review of the functional roles of non-coding RNAs, particularly microRNAs, in epithelial-to-mesenchymal transition in both developmental and pathological EMT.

Molecular alterations of cancer cell and tumour microenvironment in metastatic gastric cancer

The term metastasis is widely used to describe the endpoint of the process by which tumour cells spread from the primary location to an anatomically distant site. Achieving successful dissemination is dependent not only on the molecular alterations of the cancer cells themselves, but also on the microenvironment through which they encounter. Here, we reviewed the molecular alterations of metastatic gastric cancer (GC) as it reflects a large proportion of GC patients currently seen in clinic. We hope that further exploration and understanding of the multistep metastatic cascade will yield novel therapeutic targets that will lead to better patient outcomes.

Increased expression of microRNA-338-3p contributes to production of Dsg3 antibody in pemphigus vulgaris patients

Expression of microRNA-338-3p (miR-338-3p) was aberrantly elevated in pemphigus vulgaris (PV), although its role in PV is still unknown. The present study investigated the functional role and possible molecular mechanisms of miR-338-3p in PV. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect miR-338-3p expression in peripheral blood mononuclear cells (PBMCs) from patients with PV. Correlation with disease severity and anti-desmoglein 3 antibody (anti-Dsg3) titers were analyzed in patients with PV. The effects of overexpression and knockdown of miR-338-3p expression in PBMCs and effects on Th1 and Th2 cytokines were also examined using ELISA. The luciferase reporter analysis, RT-qPCR and western blot analysis were applied to investigate potential and functional target genes. The data showed that miR-338-3p expression was significantly upregulated in PV and the upregulation of miR-338-3p associated with disease severity and a high anti-Dsg3 antibody titer. Expression of miR-338-3p/mimic in healthy PBMCs significantly downregulated Th1 cytokine (IFN-γ) and upregulated Th2 cytokines (IL-4 and IL-10), whereas knockdown of miR-338-3p expression in PBMCs from patients with PV induced the reverse effects. Overexpression of miR-338-3p suppressed cell viability. Luciferase reporter, RT-qPCR and western blot assays idnicated that TNFR1-associated death domain protein (TRADD) was the direct and functional target of miR-338-3p. Increased expression of miR-338-3p contributed to the production of Dsg3 antibody by inhibiting TRADD expression to induce an imbalance in Th1/Th2 cell functions. Taken together, this study suggests that miR-338-3p may be used as a potential therapeutic target for PV treatment.

miR-338-3p functions as a tumor suppressor in gastric cancer by targeting PTP1B

Gastric cancer (GC) is one of the most common malignant tumors and peritoneal metastasis is the primary cause for advanced GC's mortality. Protein-tyrosine phosphatase 1B (PTP1B) functions as an oncogene and involves in carcinogenesis and cancer dissemination. However, the function and regulation of PTP1B in GC remain poorly understood. In this study, we found that PTP1B was upregulated in GC tissues and overexpression of PTP1B in vitro promoted cell migration and prevented apoptosis. Then, we predicted that PTP1B was a target of miR-338-3p and we revealed an inverse correlation between miR-338-3p levels and PTP1B protein levels in GC tissues. Next, we verified that PTP1B was inhibited by miR-338-3p via direct targeting to its 3'-untranslated regions. Moreover, overexpression of miR-338-3p in vitro attenuated GC cell migration and promoted apoptosis, and these effects could be partially reversed by reintroduction of PTP1B. Finally, we established an orthotopic xenograft model and a peritoneal dissemination model of GC to demonstrate that miR-338-3p restrained tumor growth and dissemination in vivo by targeting PTP1B. Taken together, our results highlight that PTP1B is an oncogene and is negatively regulated by miR-338-3p in GC, which may provide new insights into novel molecular therapeutic targets for GC.

Tumor-released exosomal circular RNA PDE8A promotes invasive growth via the miR-338/MACC1/MET pathway in pancreatic cancer

Circular RNA (circ-RNA) and exosomes have recently been shown to play important roles in different tumors. However, the functions and regulatory mechanisms of exosomal circ-RNA in pancreatic ductal adenocarcinoma (PDAC) tumor progression remain unclear. Here, we identified a circular RNA (circ-PDE8A) from liver-metastatic PDAC cells by microarray analysis, detected its expression levels in clinical tissues and found that high circ-PDE8A expression was correlated with lymphatic invasion, TNM stage and a poor survival rate of PDAC patients. Further study revealed that circ-PDE8A promotes the invasive growth of PDAC cells via upregulating MET. Circ-PDE8A acts as a ceRNA for miR-338 to regulate MACC1 and stimulates invasive growth via the MACC/MET/ERK or AKT pathways. We further imaged the exosome communication between tumor cells and identified the tumor secreted exosomes in blood circulation. Finally, we analyzed the circ-PDE8A expression in plasma exosomes of PDAC patients and found that exosomal circ-PDE8A was associated with progression and prognosis in PDAC patients. Thus, circ-PDE8A may play an important role in tumor invasion, and exosomal circ-PDE8A may be a useful marker of PDAC diagnosis or progression.