MicroRNAs regulate the epithelial-mesenchymal transition and influence breast cancer invasion and metastasis

E2F5 Targeted by Let-7d-5p Facilitates Cell Proliferation, Metastasis and Immune Escape in Gallbladder Cancer

BACKGROUND

Gallbladder cancer (GBC) remains a serious cause of cancer-related mortality across the globe. E2F5 has been identified to as a known oncogene in various cancers. However, the special functions of E2F5 have not been investigated in GBC.

AIMS

To explore the regulatory functions of E2F5 and its related molecular regulatory mechanism in GBC progression.

METHODS

The expression of genes were examined through qRT-PCR, western blot and IHC assay. The cell proliferation was assessed through CCK-8 and EDU assays. The cytotoxicity was tested through LDH assay. The percentage of CD8+ T cells and cell apoptosis were evaluated through flow cytometry. The binding ability was detected through luciferase reporter assay. The tumor growth was assessed through in vivo assays.

RESULTS

In this study, it was demonstrated that E2F5 expression was evaluated in GBC, and resulted into poor prognosis. Bioinformatics analysis revealed E2F5 as a target for let-7d-5p, which when overexpressed, suppressed the metastasis and proliferation of GBC through the downregulation of E2F5. It was discovered that E2F5 activates JAK2/STAT3 signaling which is suppressed by let-7d-5p, implicating this pathway as one of the effectors of the oncogenic effects of ESF5 in GBC. E2F5 had been confirmed to aggravate tumor growth in vivo.

CONCLUSION

E2F5 targeted by let-7d-5p facilitated cell proliferation, metastasis and immune escape in GBC through the JAK2/STAT3 pathway.

Cancer plasticity: Investigating the causes for this agility

Cancer is not a hard-wired phenomenon but an evolutionary disease. From the onset of carcinogenesis, cancer cells continuously adapt and evolve to satiate their ever-growing proliferation demands. This results in the formation of multiple subtypes of cancer cells with different phenotypes, cellular compositions, and consequently displaying varying degrees of tumorigenic identity and function. This phenomenon is referred to as cancer plasticity, during which the cancer cells exist in a plethora of cellular states having distinct phenotypes. With the advent of modern technologies equipped with enhanced resolution and depth, for example, single-cell RNA-sequencing and advanced computational tools, unbiased cancer profiling at a single-cell resolution are leading the way in understanding cancer cell rewiring both spatially and temporally. In this review, the processes and mechanisms that give rise to cancer plasticity include both intrinsic genetic factors such as epigenetic changes, differential expression due to changes in DNA, RNA, or protein content within the cancer cell, as well as extrinsic environmental factors such as tissue perfusion, extracellular milieu are detailed and their influence on key cancer plasticity hallmarks such as epithelial-mesenchymal transition (EMT) and cancer cell stemness (CSCs) are discussed. Due to therapy evasion and drug resistance, tumor heterogeneity caused by cancer plasticity has major therapeutic ramifications. Hence, it is crucial to comprehend all the cellular and molecular mechanisms that control cellular plasticity. How this process evades therapy, and the therapeutic avenue of targeting cancer plasticity must be diligently investigated.

The role of tumor-associated macrophages in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common head and neck cancer with a high recurrence rate and a low 5-year survival rate. Tumor-associated macrophages (TAMs) are important immune cells in the tumor microenvironment, which play an important role in the progression of many tumors. This article reviews the origin, and the role of TAMs in the invasion, metastasis, angiogenesis and immunosuppression of OSCC. Therapeutic strategies targeting TAMs are also discussed in hopes of providing new ideas for the treatment of OSCC.

Crowberry inhibits cell proliferation and migration through a molecular mechanism that includes inhibition of DEK and Akt signaling in cholangiocarcinoma

Background

Cholangiocarcinoma (CCA) is a rare biliary adenocarcinoma related to poor clinical prognosis. Crowberry is an herbal medicine used to control inflammatory diseases and reestablish antioxidant enzyme activity. Although crowberry shows significant therapeutic efficacy in various tumors and diseases, its anticancer effects and specific molecular mechanisms in CCA are poorly understood.

Aim of the study

This study was conducted to characterize crowberry effects on CCA cells behavior.

Materials and methods

The chemical profiles of crowberry extract was qualitatively analyzed by high-performance liquid chromatography (HPLC) and HPLC–tandem mass spectrometry. MTT, colony formation and EdU assays were performed to measure cell proliferation. The effect of crowberry treatment on CCA cell migration was assessed by wound healing and migration assays. Moreover, Hoechst staining assay and flow cytometry were performed to assess the cell apoptosis rate. Western blotting was used to assess the protein expression levels of key factors associated with apoptosis, the Akt signaling pathway, and the epithelial-mesenchymal transition. A xenograft model was established and immunohistochemical and H&E staining was performed to assess crowberry antitumor effects in vivo.

Results

Crowberry clearly inhibited CCA cells proliferation and migration in a dose-dependent manner and induced apoptosis in vitro. Crowberry inactivated the PI3K/Akt signaling pathway by regulating DEK in vitro and significantly inhibited tumor growth by downregulating the DEK expression in xenograft models.

Conclusion

Crowberry inhibits CCA cells proliferation and migration through a molecular mechanism that includes inhibition of DEK and Akt signaling pathway inhibition in vitro and in vivo.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00623-6.

Crowberry alterd expression levels of key mediators in PI3K/Akt signaling pathway.

Crowberry alterd expression levels of key mediators in PI3K/Akt signaling pathway.

Crowberry suppressed the expression of the proto-oncogene DEK in vivo and in vitro.

Crowberry inhibited CCA progression and migration through a molecular mechanism that includes inhibition of DEK and the Akt signaling pathway in vivo and in vitro.

MicroRNA-135 inhibits initiation of epithelial-mesenchymal transition in breast cancer by targeting ZNF217 and promoting m6A modification of NANOG

MicroRNAs play significant roles in various malignancies, with breast cancer (BC) being no exception. Consequently, we explored the functional mechanism of miR-135 in the progression of BC. In total, 55 pairs of BC and matched adjacent normal tissues were clinically collected from patients, followed by quantification of miR-135 and zinc finger protein 217 (ZNF217) expression patterns in BC tissues and cells. Accordingly, high ZNF217 expression and low miR-135 expression levels were identified in BC tissues and cells. Subsequently, the expressions of miR-135 and ZNF217 were altered to evaluate their effects on BC cell migration, invasion and EMT initiation. It was found that when ZNF217 was silenced or miR-135 was elevated, BC cell malignant behaviors were significantly inhibited, which was reproduced in nude mice for in vivo evidence. Furthermore, dual-luciferase reporter gene assay revealed the presence of direct binding between miR-135 and ZNF217. Subsequent co-immunoprecipitation, methylated-RNA binding protein immunoprecipitation and photoactivatable ribonucleoside enhanced-crosslinking and immunoprecipitation assays further revealed that ZNF217 could upregulate NANOG by reducing N6-methyladenosine levels via methyltransferase-like 13 (METTL3). Collectively, our findings highlighted the role of the miR-135/ZNF217/METTL3/NANOG axis in the progression of BC, emphasizing potential therapeutic targets ZNF217 silencing and miR-135 upregulation in preventing or treating BC.

Epithelial-to-Mesenchymal Transition Signaling Pathways Responsible for Breast Cancer Metastasis

Breast carcinoma is highly metastatic and invasive. Tumor metastasis is a convoluted and multistep process involving tumor cell disseminating from their primary site and migrating to the secondary organ. Epithelial-mesenchymal transition (EMT) is one of the crucial steps that initiate cell progression, invasion, and metastasis. During EMT, epithelial cells alter their molecular features and acquire a mesenchymal phenotype. The regulation of EMT is centered by several signaling pathways, including primary mediators TGF-β, Notch, Wnt, TNF-α, Hedgehog, and RTKs. It is also affected by hypoxia and microRNAs (miRNAs). All these pathways are the convergence on the transcriptional factors such as Snail, Slug, Twist, and ZEB1/2. In addition, a line of evidence suggested that EMT and cancer stem like cells (CSCs) are associated. EMT associated cancer stem cells display mesenchymal phenotypes and resist to chemotherapy or targeted therapy. In this review, we highlighted recent discoveries in these signaling pathways and their regulation in breast cancer metastasis and invasion. While the clinical relevance of EMT and breast cancers remains controversial, we speculated a convergent signaling network pivotal to elucidating the transition of epithelial to mesenchymal phenotypes and onset of metastasis of breast cancer cells.

A narrative review of research progress on FoxM1 in breast cancer carcinogenesis and therapeutics

OBJECTIVE

The purpose of this review is to clarify the potential roles of forkhead box transcription factor M1 (FoxM1) in the occurrence and progression of breast cancer, as well as the predictive value of FoxM1 as a prognostic biomarker and potential therapeutic target for breast cancer.

BACKGROUND

Breast cancer, well-known as a molecularly heterogeneous cancer, is still one of the most frequently diagnosed malignant tumors among females worldwide. Tumor recurrence and metastasis are the central causes of high mortality in breast cancer patients. Many factors contribute to the occurrence and progression of breast cancer, including FoxM1. FoxM1, widely regarded as a classic proliferation-related transcription factor, plays pivotal roles in the occurrence, proliferation, invasion, migration, drug resistance, and epithelial-mesenchymal transition (EMT) processes of multiple human tumors including breast cancer.

METHODS

The PubMed database was searched for articles published in English from February 2008 to May 2021 using related keywords such as "forkhead box transcription factor M1", "human breast cancer", "FoxM1", and "human tumor". About 90 research papers and reports written in English were identified, most of which were published after 2015. These papers mainly concentrated on the functions of FoxM1 in the occurrence, development, drug resistance, and treatment of human breast cancer.

CONCLUSIONS

Considering that the abnormal expression of FoxM1 plays a significant role in the proliferation, invasion, metastasis, and chemotherapy drug resistance of breast cancer, and its overexpression is closely correlated with the unfavorable clinicopathological characteristics of breast tumor patients, it is considerably important to comprehend the regulatory mechanism of FoxM1 in breast cancer. This will provide strong evidence for FoxM1 as a potential biomarker for the targeted treatment and prognostic evaluation of breast cancer patients.

Unraveling the roles of miRNAs in regulating epithelial-to-mesenchymal transition (EMT) in osteosarcoma

Osteosarcoma is one of the most prevalent primary bone tumors with a high metastatic and recurrence rate with poor prognosis. MiRNAs are short and non-coding RNAs that could regulate various cellular activities and one of them is the epithelial-to-mesenchymal transition (EMT). Osteosarcoma cells that have undergone EMT would lose their cellular polarity and acquire invasive and metastatic characteristics. Our literature search showed that many pre-clinical and clinical studies have reported the roles of miRNAs in modulating the EMT process in osteosarcoma and compared to other cancers like breast cancer, there is a lack of review article which effectively summarizes the various roles of EMT-regulating miRNAs in osteosarcoma. This review, therefore, was aimed to discuss and summarize the EMT-promoting and EMT-suppressing roles of different miRNAs in osteosarcoma. The review would begin with the discussion on the concepts and principles of EMT, followed by the exploration of the diverse roles of EMT-regulating miRNAs in osteosarcoma. Subsequently, the potential use of miRNAs as prognostic biomarkers in osteosarcoma to predict the likelihood of metastases and as therapeutic agents would be discussed.

MiRNA based tumor mutation burden diagnostic and prognostic prediction models for endometrial cancer

Uterus Corpus Endometrial cancer (UCEC) is the sixth most common malignant tumor worldwide. In this research, we identified diagnostic and prognostic biomarkers to reflect patients’ immune microenvironment and prognostic. Various data of UCEC patients from the TCGA database were obtained. Firstly, patients were divided into a high tumor mutation burden (TMB) level group and a low TMB level group according to the level of TMB. Then, differentially expressed miRNAs between the two groups were obtained. LASSO logistic regression analysis was used to construct a diagnostic model to predict the level of TMB. Univariate, multivariate, and LASSO regression analysis were used to construct a prognostic risk signature (PRS) to predict the prognosis of UCEC patients. Twenty-one miRNAs were used to construct a diagnostic model for predicting TMB levels. The AUC values of ROC curves for 21-miRNA-based diagnostic models were 0.911 in the training set, 0.827 in the test set, and 0.878 in the entire set. This diagnostic model showed positive correlation with TMB, PDL1 expression, and the infiltration of immune cells. In addition, three prognostic miRNAs were finally used to construct the PRS. The PRS was related to the expression of multiple immune checkpoints and the infiltration of multiple immune cells. Furthermore, the PRS can also reflect the response to some commonly used chemotherapy regimens. We have established a miRNA-based diagnostic model and a prognostic model that can predict the prognosis of UCEC patients and their response to chemotherapy and immunotherapy, thus providing valuable information on the choice of treatment regimen.

Effect of silencing C-erbB-2 on esophageal carcinoma cell biological behaviors by inhibiting IGF-1 pathway activation

OBJECTIVE

C-erbB-2 has been confirmed to be an oncogene that participates in cell growth, differentiation and division of tumors. We are wondered if its silenced expression can exert an anti-tumor effect. Therefore, this study is conducted to investigate the mechanism of C-erbB-2 silencing and IGF-1 pathway on esophageal carcinoma (EC) cell biological behaviors.

METHODS

The objects of study were 84 EC patients from Heping Hospital Affiliated to Changzhi Medical College, with the collection of EC tissue and adjacent normal tissue (> 5 cm away from cancer tissue). C-erbB-2 protein expression in EC tissues was detected by immunohistochemistry. Human EC cell line Eca-109 was purchased from Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. Based on different transfection protocols, EC cells with logarithmic growth phase of 3-5 passages were divided into blank control group, oe-C-erbB-2 NC group, siRNA C-erbB-2 NC group, oe-C-erbB-2 group, siRNA C-erbB-2 group, OSI-906 group, Rg5 group, Rg5 + siRNA C-erbB-2 NC group and Rg5 + siRNA C-erbB-2 group. Cell proliferation was detected by MTT assay; cell cycle distribution and apoptosis by flow cytometry; C-erbB-2, IGF-1, IGF-1R and Akt mRNA and protein expressions by qRT-PCR and western blot; and cell invasion and migration by Transwell assay and scratch test. Tumor growth was observed in male BALB/c nude mice (Shanghai Experimental Animal Center) based on Eca109 cell implantation, raising, and measurement.

RESULTS

C-erbB-2, IGF-1, IGF-1R and Akt expression were higher in EC tissues than those in adjacent tissues (all P < 0.05). Compared with blank control group, both si-C-erbB-2 and OSI-906 groups had decreased IGF-1, IGF-1R and Akt mRNA and protein expressions, decreased cell proliferation, migration and invasion, prolonged G0/G1 phase, shortened S phase, increased cell apoptosis, and inhibited tumor growth (all P < 0.05); while opposite trends were detected in C-erbB-2 vector and Rg5 groups (all P < 0.05), without statistical differences in siRNA C-erbB-2 + Rg5 group (all P > 0.05).

CONCLUSION

Silencing C-erbB-2 expression may inhibit EC cell proliferation, promote cell apoptosis and block cell cycle progression by inhibiting IGF-1 pathway activation. The beneficial effect of silencing C-erbB-2 expression can be reversed by promoting the activation of IGF-1 pathway. Findings in our study may provide potential reference for understanding the molecular mechanism of EC and supply possible axis for preventing the development of EC from the perspective of molecular biology.

DHA inhibits Gremlin-1-induced epithelial-to-mesenchymal transition via ERK suppression in human breast cancer cells

Docosahexaenoic acid (DHA) is an omega-3 fatty acid abundant in fish oils. It is known to have an inhibitory effect on various diseases such as inflammation, diabetes, and cancer. Epithelial-to-mesenchymal transition (EMT) is a process that epithelial cells gain migratory property to become mesenchymal cells involved in wound healing, organ fibrosis, and cancer progression. Gremlin-1 (GREM1) is a bone morphogenetic protein antagonist known to play a role in EMT. However, the role of GREM1 in the induction of EMT in human breast cancer cells and the effect of DHA on GREM1-induced EMT remain unclear. Establishment of GREM1 knockdown cell lines was performed using lentiviral shRNAs. Expression of EMT markers was determined by qRT-PCR and Western blotting. Effect of GREM1 and/or DHA on cell migration was investigated using wound healing assay. The level of GREM1 expression in human breast cancer tissues was determined by Oncomine database mining. GREM1 induced the expression of genes including N-cadherin, vimentin, and Slug. GREM1 promoted the migration of human breast cancer cells. GREM1 enhanced the expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and the ERK activation was involved in EMT. Interestingly, DHA reduced the expression of GREM1. DHA also inhibited the expression of mesenchymal cell-associated genes and cell migration induced by GREM1. Furthermore, DHA suppressed the expression of p-ERK induced by GREM1. These results indicate that GREM1–ERK axis plays a role in EMT in human breast cancer cells and DHA is a putative compound that can inhibit EMT by inhibiting GREM1 signal transduction.

MicroRNA-182 promotes epithelial-mesenchymal transition by targeting FOXN3 in gallbladder cancer

Increasing evidence has suggested an association between the expression profiles of microRNAs (miRs) and gallbladder cancer (GBC). Recently, miR-182 has been demonstrated to exert tumor-promoting effects. However, the biological activity and molecular mechanisms of miR-182 in GBC remain unclear. The results of the present study demonstrated that miR-182 expression was significantly upregulated in GBC tissues and cell lines (GBC-SD and SGC-996). In addition, miR-182-knockdown attenuated epithelial-mesenchymal transition (EMT) in GBC cells, as indicated by decreased cell migratory and invasive abilities, decreased vimentin expression, and increased E-cadherin expression. The activities of β-catenin and its downstream factors, Cyclin D1 and c-Myc, were also demonstrated to decrease following miR-182-knockdown. Forkhead box N3 (FOXN3) was identified as the direct target of miR-182. Overexpression of FOXN3 ameliorated EMT and the β-catenin pathway. Taken together, the results of the present study suggested that miR-182 promotes EMT in GBC cells by targeting FOXN3, which suppresses the Wnt/β-catenin pathway.

Recent Discoveries of Macromolecule- and Cell-Based Biomarkers and Therapeutic Implications in Breast Cancer

Breast cancer is the most commonly diagnosed cancer type and the leading cause of cancer-related mortality in women worldwide. Breast cancer is fairly heterogeneous and reveals six molecular subtypes: luminal A, luminal B, HER2+, basal-like subtype (ER−, PR−, and HER2−), normal breast-like, and claudin-low. Breast cancer screening and early diagnosis play critical roles in improving therapeutic outcomes and prognosis. Mammography is currently the main commercially available detection method for breast cancer; however, it has numerous limitations. Therefore, reliable noninvasive diagnostic and prognostic biomarkers are required. Biomarkers used in cancer range from macromolecules, such as DNA, RNA, and proteins, to whole cells. Biomarkers for cancer risk, diagnosis, proliferation, metastasis, drug resistance, and prognosis have been identified in breast cancer. In addition, there is currently a greater demand for personalized or precise treatments; moreover, the identification of novel biomarkers to further the development of new drugs is urgently needed. In this review, we summarize and focus on the recent discoveries of promising macromolecules and cell-based biomarkers for the diagnosis and prognosis of breast cancer and provide implications for therapeutic strategies.

Let-7d and miR-185 Impede Epithelial-Mesenchymal Transition by Downregulating Rab25 in Breast Cancer

Objective:

MicroRNAs (miRNAs) expression has deregulated in several cancer types including breast cancer (BC). The present study aims at investigating the role, mechanism, clinical value of let-7d and miR-185 in BC, and the possible correlation these miRNAs with Rab25.

Materials and Methods:

Tumor samples as well adjacent normal tissues (ANT) were acquired from fresh surgical specimens from 110 patients and the expression levels of let-7d, miR-185, Rab25, and snail were evaluated using real-time PCR. The immunohistochemical (IHC) process and western blot were done to detect the level of Rab25 and Snail protein expression in BC samples.

Results:

By comparing miRNAs expression profiles in clinical tissues of 110 patients using real-time PCR, let-7d, and miR-185 expression were dramatically downregulated in BC tissues (P < 0.05). Tumor size, stage, and lymph node metastasis were significantly related to miRNAs expression. Based on qRT-PCR and bioinformatics database analyses, we also recognized Rab25 as a possible target of miR-185 and let-7d. Rab25 expression was enhanced in BC cells and associated inversely with the expression level of mentioned miRNAs. qRT-PCR, immunohistochemistry, and western blot studies verified that Rab25 upregulation increased the levels of the snail, that key transcription factor of epithelial-mesenchymal transition (EMT).

Conclusion:

These findings demonstrated that let-7d and miR-185 inhibited EMT by targeting Rab25 expression in BC. Therefore, targeting the let-7d and miR-185/Rab25 interaction may offer new therapeutic opportunities for treating BC patients.

miRNAs in Health and Disease: A Focus on the Breast Cancer Metastatic Cascade towards the Brain

MicroRNAs (miRNAs) are small non-coding RNAs that mainly act by binding to target genes to regulate their expression. Due to the multitude of genes regulated by miRNAs they have been subject of extensive research in the past few years. This state-of-the-art review summarizes the current knowledge about miRNAs and illustrates their role as powerful regulators of physiological processes. Moreover, it highlights their aberrant expression in disease, including specific cancer types and the differential hosting-metastases preferences that influence several steps of tumorigenesis. Considering the incidence of breast cancer and that the metastatic disease is presently the major cause of death in women, emphasis is put in the role of miRNAs in breast cancer and in the regulation of the different steps of the metastatic cascade. Furthermore, we depict their involvement in the cascade of events underlying breast cancer brain metastasis formation and development. Collectively, this review shall contribute to a better understanding of the uniqueness of the biologic roles of miRNAs in these processes, to the awareness of miRNAs as new and reliable biomarkers and/or of therapeutic targets, which can change the landscape of a poor prognosis and low survival rates condition of advanced breast cancer patients.

The KN Motif and Ankyrin Repeat Domains 1/CXXC Finger Protein 5 Axis Regulates Epithelial-Mesenchymal Transformation, Metastasis and Apoptosis of Gastric Cancer via Wnt Signaling

Background

Emerging research indicates that CXXC finger protein 5 (CXXC5) is involved in the development of various cancers. Besides, KN motif and ankyrin repeat domains 1 (KANK1) was proved as a tumor suppressor in multiple cancers. Our study aimed to illustrate the functional role and mechanism of CXXC5 and KANK1 in gastric cancer (GC) pathogenesis.

Methods

The tissues of 55 GC patients and six GC cell lines were used to investigate CXXC5 and KANK1 expression using RT-qPCR. Western blot assay was conducted to measure the protein levels of CXXC5, KANK1, epithelial-mesenchymal transformation (EMT) proteins (Vimentin, E-cadherin) and Wnt signaling proteins (β-catenin, Axin2). The correlation between KANK1 and CXXC5 was estimated by Pearson’s correlation analysis. The results of Transwell assays showed the migration and invasion abilities of GC cells, while the apoptosis rate was detected by flow cytometry.

Results

The expressions of CXXC5 and KANK1 were both decreased in GC tissues and cells, compared with the normal ones (P < 0.01). Overexpressing CXXC5 significantly induced apoptosis (P < 0.05) and inhibited EMT, migration (P < 0.05) and invasion (P < 0.01) in GC cells. Wnt/β-catenin/Axin2 signaling was suppressed by CXXC5 overexpression, and activating Wnt/β-catenin/Axin2 signaling reversed the effects of CXXC5. The expression of KANK1 was found to be positively correlated with CXXC5 (r² = 0.4024). KANK1 presented similar effects with CXXC5 on GC cells; however, silencing CXXC5 or activating Wnt/β-catenin/Axin2 signaling antagonized the effects of KANK1 overexpression on EMT and apoptosis in GC (P < 0.05).

Conclusion

Our study suggested that CXXC5 was downregulated in GC and participated in EMT and apoptosis regulations via the Wnt/β-catenin/Axin2 pathway. Besides, the decreased expression of CXXC5 in GC was caused by KANK1 dysregulation.

Role of exosomal miR‑21 in the tumor microenvironment and osteosarcoma tumorigenesis and progression (Review)

Osteosarcoma is the most common bone tumor affecting both adolescents and children. Early detection is critical for the effective treatment of the disease. Derived from cancer cells, miR‑21 contained within exosomes in the tumor microenvironment may act on both cancer cells and the surrounding tumor microenvironment (TME), including immune cells, endothelial cells and fibroblasts. In human serum and plasm, the level of exosomal miR‑21 between osteosarcoma patients and healthy controls differs, supporting the role of miR‑21 as a biomarker for osteosarcoma. The involvement of a number of miR‑21 target genes in tumor progression suggests that miR‑21 may significantly affect the plasticity of cancer cells, leading to tumor progression, metastasis, angiogenesis and immune escape in osteosarcoma. Understanding the biogenesis and functions of exosomal miR‑21 is of great value for the diagnosis and therapy of cancer, including osteosarcoma. The present review discusses the role of miR‑21 in the tumor microenvironment, and in the development and progression of osteosarcoma, with an aim to summarize the functions of this miRNA in cancer.

miR-208b-5p inhibits invasion of non-small cell lung cancer through the STAT3 pathway by targeting interleukin-9

Previous studies reported a dysregulation of micro (mi)R-208b-5p expression level in various types of human cancer; however, the role of miR-208-5p in non-small cell lung cancer (NSCLC) remains unclear. Therefore, the present study aimed to determine whether miR-208b-5p could regulate NSCLC progression. A total of 62 pairs of primary tumor and adjacent normal tissues were collected from patients with NSCLC. miR-208b-5p expression level was determined by reverse transcription-quantitative polymerase chain reaction. Furthermore, miR-208b-5p mimics was transfected into NSCLC A549 and H1299 cells in order to upregulate miR-208b-5p expression. Dual-luciferase reporter assay was utilized to investigate the associations between miR-208b-5p and IL9 mRNA. The results demonstrated that miR-208b-5p expression decreased in NSCLC tissues and cell lines. Furthermore, miR-208b-5p overexpression inhibited A549 and H1299 cell proliferation and invasiveness. miR-208b-5p was demonstrated to bind directly to the 3' untranslated region of interleukin-9 (IL-9) and therefore decreased its expression. In the NSCLC-derived cell lines, miR-208b-5p inactivated IL-9/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Furthermore, enhanced IL-9 level decreased the miR-208b-5p-mediated suppression of epithelial-mesenchymal transition in NSCLC cells by inactivating the STAT3 signaling pathway. In conclusion, the findings from this study demonstrated that miR-208b-5p inhibited migration and invasion of NSCLC cells. The anti-tumor activity of miR-208b-5p may be mediated by IL-9 and STAT-3 pathway.

GRHL2 Acts as an Anti-Oncogene in Bladder Cancer by Regulating ZEB1 in Epithelial-Mesenchymal Transition (EMT) Process

PURPOSE

GRHL2 played important roles in different cancers. In this study, we aimed to investigate the roles of GRHL2 in bladder cancer.

METHODS

The immunohistochemistry assay was performed to detect the expression of GRHL2 in bladder cancer tissues and adjacent noncancerous tissues and the expression levels of GRHL2 and zinc finger E-box binding homeobox (ZEB1) mRNA in tissues were determined by qRT-PCR. In addition, qRT-PCR and Western blotting were applied to detect the expression levels of GRHL2 and ZEB1 in bladder cancer cell lines (RT4, BIU-87, 5637, T24) and immortalized human bladder epithelial cell line (SV-HUC-1). The cell models with up-regulated and down-regulated expression of GRHL2 were constructed using bladder cancer cell lines T24 and 5637 to investigate the underlying roles of GRHL2 on the proliferation, migration, invasion and EMT process of bladder cancer cells. After that, cell proliferation was evaluated by CCK8 assay, cell cycle assay and colony formation assay. Transwell assay and wound healing assay were performed to determine the invasion and migration ability of the bladder cancer cells. The expressions of epithelial-mesenchymal transition (EMT) related proteins (E-cadherin, Vimentin, Slug and Snail) were assessed by Western blot analysis. Moreover, ZEB1 and GRHL2 were co-transfected into T24 and 5637 cells and their effects on EMT process and invasive capacity of cells were examined.

RESULTS

The expression of GRHL2 was down-regulated in bladder cancer tissues and human bladder cancer cell lines compared with the normal bladder tissues and immortalized human bladder epithelial cell line. Besides, down-regulation of GRHL2 improved the proliferation ability of bladder cancer cells and promoted the EMT process through up-regulation of ZEB1. The overexpression of ZEB1 partially reversed the inhibitory effect of GRHL2 on EMT.

CONCLUSION

GRHL2 acts as an anti-oncogene to regulate bladder cancer cell proliferation and inhibit EMT by targeting ZEB1. This study may provide a theoretical basis for further research.

STRIP2, a member of the striatin-interacting phosphatase and kinase complex, is implicated in lung adenocarcinoma cell growth and migration

Lung adenocarcinoma (LUAD) accounts for ~40% of lung cancer cases, and the 5-year relative survival rate is no more than 1%. Dysregulation of components of striatin-interacting phosphatase and kinase (STRIPAK) complexes is associated with various diseases, including cancer. Striatin-interacting protein 2 (STRIP2), also called Fam40b, has been reported to regulate tumor cell growth and migration. Here, we investigated the role of STRIP2 in LUAD growth, migration and the underlying mechanisms. Analysis of data from The Cancer Genome Atlas database revealed that STRIP2 is highly expressed and predicted poor outcomes in patients with LUAD. Moreover, quantitative RT-PCR (qRT-PCR) analysis revealed that the mRNA expression of STRIP2 is greater in all tested LUAD cells than in a normal lung cell line. To investigate the function of STRIP2, we overexpressed STRIP2 in SPC-A1 cells and depleted STRIP2 in Calu-3 cells. Cell proliferation was evaluated by Cell Counting Kit-8 and colony-forming assays, and Transwell assay was employed to test cell invasion and migration. Our results indicate that STRIP2 depletion suppressed cell proliferation, invasion and migration in Calu-3 cells, and overexpression of STRIP2 had the opposite effects in SPC-A1 cells. Moreover, we discovered that STRIP2 depletion reduced the protein levels of p-Akt and phosphorylated-mammalian target of rapamycin (p-mTOR) in Calu-3 cells, whereas STRIP2 overexpression increased levels of these proteins in SPC-A1 cells. Furthermore, we found that silencing of STRIP2 clearly enhanced protein levels of E-cadherin and reduced levels of N-cadherin, Vimentin and matrix metalloproteinase-9 in Calu-3 cells, whereas overexpression of STRIP2 had the opposite effect in SPC-A1 cells. Our data indicate that STRIP2 promotes the proliferation and motility of LUAD cells, and this may be mediated through the regulation of the Akt/mTOR pathway and epithelial-mesenchymal transition. These results may facilitate the development of therapeutic strategies to treat LUAD.

Interplay between miRNAs and Genes Associated with Cell Proliferation in Endometrial Cancer

Endometrial cancer develops as a result of abnormal cell growth associated with uncontrolled cell proliferation, excessive activation of signaling pathways and miRNA activity. The aim of this study was to determine the expression profile of genes associated with cell proliferation and to assess which miRNAs can participate in the regulation of their expression. The study enrolled 40 patients with endometrial cancer and 10 patients without neoplastic changes. The expression profile of genes associated with cell proliferation and the expression profile of miRNAs were assessed using microarrays. RT-qPCR was performed to validate mRNA microarray results. The mirTAR tool was used to identify miRNAs that regulate the activity of genes associated with cell proliferation. Decreased expression of IGF1 and MYLK, as well as SOD2 overexpression, were observed in endometrial cancer using both mRNA microarrays and RT-qPCR. Microarray analysis showed low levels of NES and PRKCA, but this was only partially validated using RT-qPCR. Reduced activity of MYLK may be caused by increased miR-200c, miR-155 and miR-200b expression. Cell proliferation is disturbed in endometrial cancer, which may be associated with an overexpression of miR-200a, miR-200c, and miR-155, making it a potential diagnostic marker.

MicroRNA-33a-5p overexpression sensitizes triple-negative breast cancer to doxorubicin by inhibiting eIF5A2 and epithelial-mesenchymal transition

Drug resistance is a significant obstacle when treating triple-negative breast cancer (TNBC). Several studies have demonstrated that microRNAs (miRNAs) have essential roles in regulating drug resistance in different types of cancer. miR-33a-5p has previously been reported to be a tumor suppressor in several types of cancer. However, its role in breast cancer remains unknown. The present study aimed to investigate the role of miR-33a-5p in the chemoresistance of TNBC and uncover its potential molecular mechanisms. Cell Counting Kit-8 assay was used to examine cell proliferation, reverse transcription-quantitative PCR analysis was used to examine miR-33a levels, and western blotting and immunofluorescence assays were used to examine the expression of epithelial-mesenchymal transition (EMT)-associated proteins and of eukaryotic translation initiation factor 5A2 (eIF5A2). The results indicated that miR-33a-5p expression was lower in TNBC cells compared with non-TNBC cells. miR-33a-5p overexpression significantly improved the doxorubicin (Dox) sensitivity of TNBC cells, but not that of non-TNBC cells. It was then observed that Dox treatment inhibited miR-33a-5p expression and induced EMT in TNBC cells, by increasing the expression levels of vimentin, while decreasing the expression levels of E-cadherin. Furthermore, it was revealed that forced expression of miR-33a-5p attenuated Dox-induced EMT. eIF5A2 was identified as a potential target of miR-33a-5p, and miR-33a-5p overexpression inhibited the expression of eIF5A2. eIF5A2 inhibition, via its inhibitor GC7, sensitized TNBC cells to Dox and reversed Dox-induced EMT. Overall, the present study demonstrated that miR-33a-5p enhanced the sensitivity of TNBC cells to Dox, by suppressing eIF5A2 expression and reversing Dox-induced EMT, providing a potential therapeutic target for treating drug-resistant TNBC.

Bioinformatics prediction and experimental validation of a novel microRNA: hsa-miR-B43 within human CDH4 gene with a potential metastasis-related function in breast cancer

As a class of short noncoding RNAs, microRNAs (miRNAs) play a key role in the modulation of gene expression. Although, the regulatory roles of currently identified miRNAs in various cancer types including breast cancer have been well documented, there are many as yet undiscovered miRNAs. The aim of the current study was to bioinformatically reanalyze a list of 189 potentially new miRNAs introduced in a previously published paper (PMID: 21346806) and experimentally explore the existence and function of a candidate one: hsa-miR-B43 in breast cancer cells. The sequences of 189 potential miRNAs were re-checked in the miRbase database. Genomic location and conservation of them were assessed with the University of California Santa Cruz (UCSC) genome browser. SSC profiler, RNAfold, miRNAFold, MiPred, and FOMmiR bioinformatics tools were furthermore utilized to explore potential hairpin structures and differentiate real miRNA precursors from pseudo ones. hsa-miR-B43 was finally selected as one of the best candidates for laboratory verification. The expression and function of hsa-miR-B43 were examined by real-time polymerase chain reaction, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and wound-healing assays. DIANA-microT, RNAhybrid and Enrichr tools were used to predict the miRNA target genes and for further enrichment analysis. We could detect the exogenous and endogenous expression of hsa-miR-B43, as a real novel miRNA, in cancer cell lines. Gene Ontology enrichment, pathway analysis and wound-healing assay results furthermore confirmed that a metastasis-related function may be assigned to hsa-miR-B43. Our results introduced hsa-miR-B43, as a novel functional miRNA, which might play a role in the metastatic process. Further studies will be necessary to completely survey the existence and function of hsa-miR-B43 in other cancer types.

MicroRNA‑124 suppresses cell proliferation and invasion of triple negative breast cancer cells by targeting STAT3

MicroRNAs (miRNAs) are pivotal regulators of the progression of carcinogenesis and negatively regulate the expression of tumour‑associated genes. Downregulation of miR‑124 expression has been demonstrated in various human cancer tissues, wherein miR‑124 serves as a tumour suppressor by targeting oncogenes. However, its function and underlying mechanism of action remain unclear in breast cancer. In the present study, the tissue‑specific expression of miR‑124 was detected in 10 paired triple‑negative breast cancer and normal tissues, and its inhibitory effects on cell growth and invasion were evaluated in vitro and in vivo. Bioinformatics analysis identified signal transducer and activator of transcription 3 (STAT3), a well‑known oncogene in breast cancer, as the potential target. Upregulation of miR‑124 expression decreased STAT3 mRNA and protein levels in breast cancer cells and the relative luciferase activity. Rescue experiments revealed that the transfection of a STAT3 expression plasmid reversed the inhibitory effect of miR‑124 on the proliferation and invasion of MDA‑MB‑468 cells. These data demonstrate that miR‑124 serves vital roles in the suppression of triple‑negative breast cancer via inhibition of cell proliferation and invasion through STAT3. These results highlight the potential role of miR‑124 as a diagnostic or therapeutic target in patients with breast cancer.

Suppressive effect of exogenous miR-16 and miR-34a on tumorigenesis of breast cancer cells

Recent investigations have shown tumor-suppressive roles for miR-16 and miR-34a. They also share some features in regard to targeting cancer cell signaling pathways which they control. Therefore, in this study, we aimed to further scrutinize whether exogenous induction of mature miR-34a and miR-16 can collaborate in breast tumor suppression. MDA-MB-231 and SK-BR-3 human breast cancer cell lines were cultured and transfected twice with hsa-miR-16-5p and hsa-miR-34a-5p mimics individually or in combination. The cells were analyzed for apoptosis rate and cell cycle indices by flow cytometry. Also, the expression of several invasion and the epithelial-mesenchymal transition markers was evaluated at gene and protein levels by quantitative real-time polymerase chain reaction and western blot analysis, respectively. Assessment of invasiveness and migratory potential of the transfected cells was performed using three-dimensional spheroid formation and wound-healing assay, respectively. In both cell lines, miR-16 and miR-34a induced apoptosis and cell-cycle arrest and also suppressed invasion and migration. Some of these effects, like cell-cycle arrest and induction of apoptosis, were significantly higher when using both microRNAs than when using them individually for transfection of the cells. Our results are indicating that miR-16 and miR-34a can collaborate in breast tumor suppression.

The cigarette smoke components induced the cell proliferation and epithelial to mesenchymal transition via production of reactive oxygen species in endometrial adenocarcinoma cells

Cigarette smoke (CS) causes about 480,000 deaths each year worldwide and is well-known to have harmful effects on the human body, leading to heart disease, stroke, lung cancer, and cardiovascular problems. In the present study, the effects of acrylonitrile (AN), benzo(a)pyrene (B(a)P), formaldehyde (FOR), isoprene (ISO), nicotine-derived nitrosamine ketone (NNK), which are the main components of CS, on the proliferation, invasion, and the epithelial-mesenchymal transition (EMT) process of human Ishikawa endometrial adenocarcinoma cells were investigated. Treating Ishikawa cells with CS components resulted in increased cell growth and altered expression of cell cycle-related genes: the protein expression of cyclin D & E increased, while the levels of p21 & p27 were reduced following treatment of these five CS components. In addition, CS components increased the invasion capacity of Ishikawa cells. The expression of the epithelial markers, E-cadherin and occludin, were significantly decreased, while the expression of the mesenchymal marker, N-cadherin, was significantly increased by CS components. In dichloro-dihydro-fluorescein diacetate (H2DCF-DA) assay, ROS production increased by treatment of CS components. The CS components activated the ROS-p38 MAPK-EMT pathway by increasing the level of phosphorylated p38 MAPK and p44/42 (ERK1/2), and by up-regulating Snail and Slug, the transcription factors for EMT. Taken together, these results indicate that CS components can promote progression of endometrial adenocarcinoma via increasing cell proliferation and the ROS-mediated EMT process.

The therapeutic effect of miR-125b is enhanced by the prostaglandin endoperoxide synthase 2/cyclooxygenase 2 blockade and hampers ETS1 in the context of the microenvironment of bone metastasis

Bone is the most common site for breast cancer spread. In the pro-metastatic cell line 1833, derived from MDA-MB-231 breast adenocarcinoma cells, both hypoxia and hepatocyte growth factor (HGF) influence the effect of miR-125b on ETS proto-oncogene 1 transcription factor (ETS1). The effect of hypoxia inducible factor 1 alpha subunit (HIF1A), known to promote metastatic spread by upregulating prostaglandin endoperoxide synthase 2 (PTGS2), may be dampened by miR-125b targeting PTGS2. Here, we investigated whether miR-125b plays a role in breast cancer metastasis by measuring its activity in response to the chemotherapeutic agent NS-398 in a xenograft model. NS-398 is typically used in the clinic to target PTGS2. We also aimed to describe the molecular mechanisms in vitro, since the enhancement of epithelial properties may favor the efficacy of therapies. We report that in the xenograft model, miR-125b reduced metastasis to the bone. We also report suppression of PTGS2 enhanced survival by decreasing HIF1A in cells within the bone marrow. In 1833 cells transfected with a miR-125b mimic we observed several phenotypic changes including enhancement of the epithelial marker E-cadherin, a reduction of mesenchymal-associated genes and a reduction of WNT-associated stem cell signaling. Our findings suggest that in vivo, key players of the bone microenvironment promoting breast cancer spread are regulated by miR-125b. In future, biological molecules imitating miR-125b may enhance the sensitivity of chemotherapeutic agents used to counteract bone metastases.

Plantamajoside inhibits lipopolysaccharide-induced epithelial-mesenchymal transition through suppressing the NF-κB/IL-6 signaling in esophageal squamous cell carcinoma cells

Plantamajoside (PMS) is a major compound of Plantago asiatica and possesses anti-tumor activity. However, the effect of PMS on esophageal squamous cell carcinoma (ESCC) and the underlying mechanism of action are unclear. The present study aimed to evaluate the effect of PMS on lipopolysaccharide (LPS)-induced epithelial-mesenchymal transition (EMT) in ESCC. The results showed that PMS inhibited viability of ESCC cell lines (Eca-109 and TE-1) in a concentration-dependent manner. PMS also inhibited LPS-induced EMT in ESCC cells. PMS inhibited LPS-induced activation of the NF-κB pathway and IL-6 expression. PMS also suppressed IL-6-induced EMT in ESCC cells. Treatment of BAY11-7082 (an inhibitor of NF-κB) or antibody against IL-6 alleviated the effect of LPS-induced EMT in ESCC cells. Besides, inhibition of NF-κB decreased IL-6 expression. In conclusion, the results indicated that PMS inhibited LPS-induced EMT through suppressing the NF-κB/IL-6 signaling in ESCC cell lines, suggesting that PMS might be a useful agent for the treatment of ESCC.

Long non-coding RNA BCYRN1 promotes the proliferation and metastasis of cervical cancer via targeting microRNA-138 in vitro and in vivo

Cervical cancer is one of the most malignant types of tumor and the fourth leading cause of cancer-associated mortality in females worldwide. High expression of brain cytoplasmic RNA 1 (BCYRN1) has been detected in various tumors. The present study aimed to investigate the effect of BCYRN1 in the viability and motility of cervical cancer, and the relevant mechanism. The results demonstrated that BCYRN1 was upregulated in cervical cancer tissues compared with normal tissues. Elevated levels of BCYRN1 were also detected in three human cervical cancer cell lines (SiHa, HeLa and CaSki) compared with non-cancerous ectocervical epithelial cell line (Ect1/E6E7). The expression of BCYRN1 was suppressed following transfection with small interfering RNA (siRNA) in HeLa cells. The silence of BCYRN1 significantly reduced cell viability and motility. Furthermore, microRNA (miR)-138 was predicted as a direct target of BCYRN1 and the expression of miR-138 was elevated in HeLa cells transfected with BCYRN1 siRNA. Subsequently, elevated levels of miR-138 were suppressed by transfection with miR-138 inhibitor in HeLa cells pretreated with BCYRN1 siRNA. The targeting association between BCYRN1 and miR-138 was supported by luciferase reporter assays. Additionally, BCYRN1 siRNA partially counteracted the effect of miR-138 inhibitor on promoting cell viability and mobility in HeLa cells. Finally, the in vivo experiment verified that BCYRN1 siRNA was able to prevent tumor growth, and reduced the expression of migration marker proteins metalloproteinase 2 and vascular endothelial cell growth factor, with enhanced expression levels of miR-138. These results suggest that lncRNA BCYRN1 promotes the proliferation and invasion of cervical cancer via targeting miR-138.

GSE1 predicts poor survival outcome in gastric cancer patients by SLC7A5 enhancement of tumor growth and metastasis

Gastric cancer remains a malignancy with poor survival outcome. We herein report that GSE1, a proline-rich protein, possesses a role in the progression of human gastric cancer. The expression of GSE1 was observed to be much higher in human gastric cancer tissues compared with normal gastric tissues, and GSE1 expression correlated positively with lymph node metastasis, histological grade, depth of invasion, and clinical stage in gastric cancer patients. Moreover, GSE1 expression was also associated with decreased post-operative relapse-free survival and overall survival in the cohort. The forced expression of GSE1 in gastric cancer cell lines resulted in increased cell proliferation, increased colony formation, enhanced cell migration, and invasion. Furthermore, forced expression of GSE1 also increased tumor size and enhanced lung metastasis in xenograft models. The depletion of endogenous GSE1 with shRNAs decreased the oncogenicity and invasiveness of gastric cancer cells both in vitro and in vivo In addition, GSE1 was determined to be a direct target of miR-200b and miR-200c. Furthermore, GSE1 positively regulated the downstream gene SLC7A5 (also known as LAT-1), which was scanned and verified from mRNA sequencing. GSE1 therefore possesses an oncogenic role in human gastric cancer, and targeted therapeutic approaches to inhibit GSE1 function in gastric cancer warrant further consideration.

Decoding colorectal cancer epigenomics

Colorectal cancer (CRC) is very heterogeneous and presents different types of epigenetic alterations including DNA methylation, histone modifications and microRNAs. These changes are considered as characteristics of various observed clinical phenotypes. Undoubtedly, the discovery of epigenetic pathways with novel epigenetic-related mechanisms constitutes a promising advance in cancer biomarker discovery. In this review, we provide an evidence-based discussing of the current understanding of CRC epigenomics and its role in initiation, epithelial-to-mesenchymal transition and metastasis. We also discuss the recent findings regarding the potential clinical perspectives of these alterations as potent biomarkers for CRC diagnosis, prognosis, and therapy in the era of liquid biopsy.

The Epithelial-to-Mesenchymal Transition in Breast Cancer: Focus on Basal-Like Carcinomas

Breast cancer is a heterogeneous disease that is characterized by a high grade of cell plasticity arising from the contribution of a diverse range of factors. When combined, these factors allow a cancer cell to transition from an epithelial to a mesenchymal state through a process of dedifferentiation that confers stem-like features, including chemoresistance, as well as the capacity to migrate and invade. Understanding the complex events that lead to the acquisition of a mesenchymal phenotype will therefore help to design new therapies against metastatic breast cancer. Here, we recapitulate the main endogenous molecular signals involved in this process, and their cross-talk with paracrine factors. These signals and cross-talk include the extracellular matrix; the secretome of cancer-associated fibroblasts, macrophages, cancer stem cells, and cancer cells; and exosomes with their cargo of miRNAs. Finally, we highlight some of the more promising therapeutic perspectives based on counteracting the epithelial-to-mesenchymal transition in breast cancer cells.

Targeting epithelial-mesenchymal plasticity in cancer: clinical and preclinical advances in therapy and monitoring

The concept of epithelial-mesenchymal plasticity (EMP), which describes the dynamic flux within the spectrum of phenotypic states that invasive carcinoma cells may reside, is being increasingly recognised for its role in cancer progression and therapy resistance. The myriad of events that are able to induce EMP, as well as the more recently characterised control loops, results in dynamic transitions of cancerous epithelial cells to more mesenchymal-like phenotypes through an epithelial-mesenchymal transition (EMT), as well as the reverse transition from mesenchymal phenotypes to an epithelial one. The significance of EMP, in its ability to drive local invasion, generate cancer stem cells and facilitate metastasis by the dissemination of circulating tumour cells (CTCs), highlights its importance as a targetable programme to combat cancer morbidity and mortality. The focus of this review is to consolidate the existing knowledge on the strategies currently in development to combat cancer progression via inhibition of specific facets of EMP. The prevalence of relapse due to therapy resistance and metastatic propensity that EMP endows should be considered when designing therapy regimes, and such therapies should synergise with existing chemotherapeutics to benefit efficacy. To further improve upon EMP-targeted therapies, it is imperative to devise monitoring strategies to assess the impact of such treatments on EMP-related phenomenon such as CTC burden, chemosensitivity/-resistance and micrometastasis in patients.