miR-564 acts as a dual inhibitor of PI3K and MAPK signaling networks and inhibits proliferation and invasion in breast cancer

The role of miRNAs as biomarkers in breast cancer

Breast cancer (BC) is the second most common cause of deaths reported in women worldwide, and therefore there is a need to identify BC patients at an early stage as timely diagnosis would help in effective management and appropriate monitoring of patients. This will allow for proper patient monitoring and effective care. However, the absence of a particular biomarker for BC early diagnosis and surveillance makes it difficult to accomplish these objectives. miRNAs have been identified as master regulators of the molecular pathways that are emphasized in various tumors and that lead to the advancement of malignancies. Small, non-coding RNA molecules known as miRNAs target particular mRNAs to control the expression of genes. miRNAs dysregulation has been linked to the start and development of a number of human malignancies, including BC, since there is compelling evidence that miRNAs can function as tumor suppressor genes or oncogenes. The current level of knowledge on the role of miRNAs in BC diagnosis, prognosis, and treatment is presented in this review. miRNAs can regulate the tumorigenesis of BC through targeting PI3K pathway and can be used as prognostic or diagnostic biomarkers for BC therapy. Some miRNAs, like miR-9, miR-10b, and miR-17-5p, are becoming known as biomarkers of BC for diagnosis, prognosis, and therapeutic outcome prediction. Other miRNAs, like miR-30c, miR-187, and miR-339-5p, play significant roles in the regulation of hallmark functions of BC, including invasion, metastasis, proliferation, resting death, apoptosis, and genomic instability. Other miRNAs, such as miR-155 and miR-210, are circulating in bodily fluids and are therefore of interest as novel, conveniently accessible, reasonably priced, non-invasive methods for the customized care of patients with BC.

Targeting TACC3 Induces Immunogenic Cell Death and Enhances T-DM1 Response in HER2-Positive Breast Cancer

Trastuzumab emtansine (T-DM1) was the first and one of the most successful antibody-drug conjugates (ADC) approved for treating refractory HER2-positive breast cancer. Despite its initial clinical efficacy, resistance is unfortunately common, necessitating approaches to improve response. Here, we found that in sensitive cells, T-DM1 induced spindle assembly checkpoint (SAC)-dependent immunogenic cell death (ICD), an immune-priming form of cell death. The payload of T-DM1 mediated ICD by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which were lost in resistance. Accordingly, ICD-related gene signatures in pretreatment samples correlated with clinical response to T-DM1-containing therapy, and increased infiltration of antitumor CD8+ T cells in posttreatment samples was correlated with better T-DM1 response. Transforming acidic coiled-coil containing 3 (TACC3) was overexpressed in T-DM1-resistant cells, and T-DM1 responsive patients had reduced TACC3 protein expression whereas nonresponders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacologic inhibition of TACC3 restored T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition in vivo elicited ICD in a vaccination assay and potentiated the antitumor efficacy of T-DM1 by inducing dendritic cell maturation and enhancing intratumoral infiltration of cytotoxic T cells. Together, these results illustrate that ICD is a key mechanism of action of T-DM1 that is lost in resistance and that targeting TACC3 can restore T-DM1-mediated ICD and overcome resistance.

SIGNIFICANCE

Loss of induction of immunogenic cell death in response to T-DM1 leads to resistance that can be overcome by targeting TACC3, providing an attractive strategy to improve the efficacy of T-DM1.

Machine learning-based prediction model for distant metastasis of breast cancer

BACKGROUND

Breast cancer is the most prevalent malignancy in women. Advanced breast cancer can develop distant metastases, posing a severe threat to the life of patients. Because the clinical warning signs of distant metastasis are manifested in the late stage of the disease, there is a need for better methods of predicting metastasis.

METHODS

First, we screened breast cancer distant metastasis target genes by performing difference analysis and weighted gene co-expression network analysis (WGCNA) on the selected datasets, and performed analyses such as GO enrichment analysis on these target genes. Secondly, we screened breast cancer distant metastasis target genes by LASSO regression analysis and performed correlation analysis and other analyses on these biomarkers. Finally, we constructed several breast cancer distant metastasis prediction models based on Logistic Regression (LR) model, Random Forest (RF) model, Support Vector Machine (SVM) model, Gradient Boosting Decision Tree (GBDT) model and eXtreme Gradient Boosting (XGBoost) model, and selected the optimal model from them.

RESULTS

Several 21-gene breast cancer distant metastasis prediction models were constructed, with the best performance of the model constructed based on the random forest model. This model accurately predicted the emergence of distant metastases from breast cancer, with an accuracy of 93.6 %, an F1-score of 88.9 % and an AUC value of 91.3 % on the validation set.

CONCLUSION

Our findings have the potential to be translated into a point-of-care prognostic analysis to reduce breast cancer mortality.

The crosstalk between miRNAs and signaling pathways in human cancers: Potential therapeutic implications

MicroRNAs (miRNAs) are increasingly recognized as central players in the regulation of eukaryotic physiological processes. These small double stranded RNA molecules have emerged as pivotal regulators in the intricate network of cellular signaling pathways, playing significant roles in the development and progression of human cancers. The central theme in miRNA-mediated regulation of signaling pathways involves their ability to target and modulate the expression of pathway components. Aberrant expression of miRNAs can either promote or suppress key signaling events, influencing critical cellular processes such as proliferation, apoptosis, angiogenesis, and metastasis. For example, oncogenic miRNAs often promote cancer progression by targeting tumor suppressors or negative regulators of signaling pathways, thereby enhancing pathway activity. Conversely, tumor-suppressive miRNAs frequently inhibit oncogenic signaling by targeting key components within these pathways. This complex regulatory crosstalk underscores the significance of miRNAs as central players in shaping the signaling landscape of cancer cells. Furthermore, the therapeutic implications of targeting miRNAs in cancer are substantial. miRNAs can be manipulated to restore normal signaling pathway activity, offering a potential avenue for precision medicine. The development of miRNA-based therapeutics, including synthetic miRNA mimics and miRNA inhibitors, has shown promise in preclinical and clinical studies. These strategies aim to either enhance the activity of tumor-suppressive miRNAs or inhibit the function of oncogenic miRNAs, thereby restoring balanced signaling and impeding cancer progression. In conclusion, the crosstalk between miRNAs and signaling pathways in human cancers is a dynamic and influential aspect of cancer biology. Understanding this interplay provides valuable insights into cancer development and progression. Harnessing the therapeutic potential of miRNAs as regulators of signaling pathways opens up exciting opportunities for the development of innovative cancer treatments with the potential to improve patient outcomes. In this chapter, we provide an overview of the crosstalk between miRNAs and signaling pathways in the context of cancer and highlight the potential therapeutic implications of targeting this regulatory interplay.

Reviving immunogenic cell death upon targeting TACC3 enhances T-DM1 response in HER2-positive breast cancer

Immunogenic cell death (ICD), an immune-priming form of cell death, has been shown to be induced by several different anti-cancer therapies. Despite being the first and one of the most successful antibody-drug conjugates (ADCs) approved for refractory HER2-positive breast cancer, little is known if response and resistance to trastuzumab emtansine (T-DM1) involves ICD modulation that can be leveraged to enhance T-DM1 response. Here, we report that T-DM1 induces spindle assembly checkpoint (SAC)-dependent ICD in sensitive cells by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which are lost in resistance. Accordingly, an ICD-related gene signature correlates with clinical response to T-DM1-containing therapy. We found that transforming acidic coiled-coil containing 3 (TACC3) is overexpressed in T-DM1 resistant cells, and that T-DM1 responsive patients have reduced TACC3 protein while the non-responders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacological inhibition of TACC3 revives T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition elicits ICD in vivo shown by vaccination assay, and it potentiates T-DM1 by inducing dendritic cell (DC) maturation and enhancing infiltration of cytotoxic T cells in the human HER2-overexpressing MMTV.f.huHER2#5 (Fo5) transgenic model. Together, our results show that ICD is a key mechanism of action of T-DM1 which is lost in resistance, and that targeting TACC3 restores T-DM1-mediated ICD and overcomes resistance.

The Role of MicroRNAs in Development of Endometrial Cancer: A Literature Review

Endometrial cancer (EC) ranks as the second most common gynaecological cancer worldwide. EC patients are diagnosed at an early clinical stage and generally have a good prognosis. Therefore, there is a dire need for development of a specific marker for early detection of endometrial adenocarcinoma. The development of EC is conditioned by a multistep process of oncogenic upregulation and tumor suppressor downregulation as shown by molecular genetic evidence. In this setting, microRNAs appear as significant regulators of gene expression and several variations in the expression of microRNAs have been implicated in normal endometrium, endometrial tissue, metrorrhagia, and endometrial cancer. Furthermore, microRNAs act as highly precise, sensitive, and robust molecules, making them potential markers for diagnosing specific cancers and their progression. With the rising incidence of EC, its management remains a vexing challenge and diagnostic methods for the disease are limited to invasive, expensive, and inaccurate tools. Therefore, the prospect of exploiting the utility of microRNAs as potential candidates for diagnosis and therapeutic use in EC seems promising.

Exosomal miRNAs as novel avenues for breast cancer treatment

Breast cancer is the most commonly diagnosed cancer and a leading cause of death in women worldwide. It is a heterogeneous disease, as shown by the gene expression profiles of breast cancer samples. It begins in milk-producing ducts, with a high degree of diversity between and within tumors, as well as among cancer-bearing individuals. The enhanced prevalence of breast cancer is influenced by various hormonal, lifestyle, and environmental factors, and very early onset of the disease correlates strongly with the risk of local and distant recurrence. Many subtypes are difficult to treat with conventional therapeutic modalities, and therefore, optimal management and early diagnosis are the first steps to minimizing the mortality linked with breast cancer. The use of newer methods of nanotechnology extends beyond the concept of synthesizing drug delivery mechanisms into the creation of new therapeutics, such as delivering chemotherapeutics with nanomaterial properties. Exosomes, a class of nanovesicles, are emerging as novel tools for deciphering the patient-specific proteins and biomarkers across different disease models, including breast cancer. In this review, we address the role of exosomal miRNA in breast cancer diagnosis and treatment.

The Expression of GPR30 in Iron-Overloaded Atypical Ovarian Epithelium and Ectopic Endometrium Is Closely Correlated with Transferrin Receptor and Pi3K

Background. The mechanism of atypical hyperplasia of the ovarian epithelium and ectopic endometrium caused by iron overload remains unclear. Accordingly, we investigated possible effects on the human ovarian ectopic endometrium and ovarian epithelium by producing a high-iron environment with rat ovaries. Objective. Human ovarian ectopic endometrium with atypical hyperplasia was collected, and the correlation between transferrin receptor GPR30 and Pi3K protein expression was studied by immunohistochemistry staining. Twenty SPF Sprague–Dawley female rats were microinjected with iron into one side of the ovary once a month, and the other ovary was used as the control. After 10 months of microinjection, the iron histological analysis was examined by Prussian blue staining, and ovarian endometrium morphology was assessed by HE staining. Abnormal lesion changes were measured by Pi3K staining. Evaluation of GPR30 was performed using reverse transcription PCR (RT-PCR) and western blotting, and the interrelationship between GPR30 and Pi3K was also assayed. Results. GPR30 was significantly increased and correlated with the transferrin receptor and Pi3K in atypical human ovarian ectopic endometrium. Iron overload was confirmed in the 20 microinjected ovary cortexes, epithelial hyperplasia was observed in 12 ovaries, and papillary atypical hyperplasia was noted in eight ovaries. The RNA and protein levels of GPR30 were significantly increased in atypical hyperplasia compared to hyperplasia tissue samples. A positive relationship between GPR30 and Pi3K was found ( $P=0.001$ ). Conclusion. The results suggest that persistent iron exposure may be a potential stimulus for ovarian endometriosis with atypical changes, and the abnormal increase in the new estrogen receptor GPR30 is closely related to this process.

miR-564: A potential regulator of vascular smooth muscle cells and therapeutic target for aortic dissection

BACKGROUND

Aortic dissection (AD) is a lethal cardiac disorder and one of the most concerning cardiovascular diseases (CVDs). Increasing evidence indicates that human aortic vascular smooth muscle cells (VSMCs) play a crucial role in the pathogenesis of AD, especially related to phenotypic transformation. And notablely, the development of AD is also accompanied by inflammation.

METHODS

By using quantitative real-time PCR and fluorescence in situ hybridization (FISH), we detected the expression levels of miR-564 in vitro and in vivo. The effects of miR-564 proliferation and migration were investigated in VSMCs. The downstream targets of miR-564 were found by bioinformatics analyse, and verified in the regulation on VSMCs. An AD murine model was constructed and clinical evaluation was performed to explore the critical roles of miR-564 in vivo. At the same time, the level of inflammation was detected using quantitative real-time PCR and immunofluorescence.

RESULTS

Overexpression of miR-564 inhibited cell proliferation and migration, as well as phenotype switch, with or without platelet-derived growth factor BB (PDGF-BB) treatment, whereas downregulation of miR-564 led to opposite results. Mechanistically, miR-564 directly interacted with the target genes proto-oncogene (SKI) and neurogranin (NRGN) to regulate the biological functions of VSMCs. In particular, animal experiments demonstrated that miR-564 can alleviate the progression of AD mainly through mediating phenotypic swithing and inflammation which was consistent with clinical evaluation.

CONCLUSIONS

Our study identified miR-564 as a significant molecule that attenuates AD progression by inhibiting inflammation and VSMCs proliferation, migration and phenotypic transformation, suggesting that it may be a potential therapeutic target for AD.

Silencing of circDPP4 suppresses cell progression of human prostate cancer and enhances docetaxel cytotoxicity through regulating miR-564/ZIC2 axis

BACKGROUND

Circular RNA derived from dipeptidyl peptidase 4 (circDPP4; ID: hsa_circ_0056881) is one top increased circRNA in prostate cancer (PC), and docetaxel (DTX)-based chemotherapy is the primary therapeutic choice for PC. However, its repertoire in PC development and chemoresistance remains to be documented.

METHODS

Expression of circDPP4, microRNA (miR)-564 and zinc finger of the cerebellum 2 (ZIC2) was detected by real-time quantitative PCR and western blotting; the direct interaction was validated by RNA pull-down assay, dual-luciferase reporter assay and RNA immunoprecipitation. Cell progression was measured by cell counting kit-8, colony formation assay, flow cytometry, Transwell assay, xenograft experiment, and immunohistochemistry. DTX cytotoxicity was confirmed by MTT cell viability assay.

RESULTS

Expression of circDPP4 is upregulated in PC tumors from 60 patients and PC cell lines, and higher circDPP4 might predict poor overall survival. Decreasing circDPP4 suppresses cell proliferation, colony formation, migration/invasion, and 50% inhibitory concentration of DTX in PC cells, and promotes apoptosis rate. Both overexpressing miR-564 and inhibiting ZIC2 could imitate those effects, while inhibiting miR-564 and restoring ZIC2 could separately counteract that. Mechanistically, circDPP4 functions as miR-564 sponge and regulates the expression of ZIC2, a target gene for miR-564. Tumor growth is retarded by silencing circDPP4, accompanied with elevated miR-564 and attenuated Ki-67 and ZIC2.

CONCLUSION

Blocking circDPP4 antagonizes cell progression of PC and contributes to in vitro DTX cytotoxicity via regulating miR-564/ZIC2 axis, at least. This study suggests circDPP4 as a potential biomarker and target for PC.

Crosstalk between miRNA and PI3K/AKT/mTOR signaling pathway in cancer

Phosphoinositide-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important proliferative signaling pathways with critical undeniable function in various aspects of cancer initiation/progression, including proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. On the other hand, numerous genetic alterations in the key genes involved in the PI3K/AKT/mTOR signaling pathway have been identified in multiple solid and hematological tumors. In addition, accumulating recent evidences have demonstrated a reciprocal interaction between this signaling pathway and microRNAs, a large group of small non-coding RNAs. Therefore, in this review, it was attempted to discuss about the interaction between key components of PI3K/AKT/mTOR signaling pathway with various miRNAs and their importance in cancer biology.

Circular RNA circ-ERBB2 promotes HER2-positive breast cancer progression and metastasis via sponging miR-136-5p and miR-198

Background

Circular RNAs (circRNAs) are pivotal regulators of various human cancers and circ-ERBB2 is abnormally expressed in breast cancer cells. However, the role and mechanism of circ-ERBB2 in HER2-positive breast cancer are still unknown.

Methods

The circ-ERBB2 expressions in the tumor tissues of HER2-positive breast cancer patients were tested using quantitative real-time PCR. The circ-ERBB2 function was investigated by cell counting kit 8 assay, Transwell, flow cytometry and Western blot. Mechanistically, fluorescence in situ hybridization, RNA immunoprecipitation, RNA pull-down and dual-luciferase reporter gene assays were conducted to confirm the interaction between circ-ERBB2 and miR-136-5p or miR-198 in HER2-positive breast cancer cells.

Results

Circ-ERBB2 was elevated in the tumor tissues of HER2-positive breast cancer patients. Functionally, the interference with circ-ERBB2 repressed HER2-positive breast cancer cell proliferation, migration, invasion and accelerated cell apoptosis. Furthermore, the mechanistic analysis corroborated that circ-ERBB2 acted as a competing endogenous RNA for miR-136-5p or miR-198 to relieve the repressive influence of miR-136-5p or miR-198 on its target transcription factor activator protein 2C (TFAP2C). Meanwhile, in vivo assays further corroborated the oncogenic function of circ-ERBB2 in HER2-positive breast cancer.

Conclusions

Circ-ERBB2 accelerated HER2-positive breast cancer progression through the circ-ERBB2/miR-136-5p/TFAP2C axis or the circ-ERBB2/miR-198/TFAP2C axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03114-8.

Soluble Epoxide Hydrolase Inhibitors Regulate Ischemic Arrhythmia by Targeting MicroRNA-1

Background: Soluble epoxide hydrolase inhibitors (sEHis) inhibit the degradation of epoxyeicosatrienoic acids (EETs) in cells, and EETs have antiarrhythmic effects. Our previous experiments confirmed that t-AUCB, a preparation of sEHis, inhibited ischemic arrhythmia by negatively regulating microRNA-1 (miR-1), but its specific mechanism remained unclear. Aim: This study aimed to examine the role of serum response factor (SRF) and the PI3K/Akt/GSK3β pathway in t-AUCB-mediated regulation of miR-1 and the interaction between them. Methods/Results: We used SRF small interfering RNA (siSRF), SRF small hairpin (shSRF) RNA sequence adenovirus, PI3K/Akt/GSK3β pathway inhibitors, t-AUCB, and 14,15-EEZE (a preparation of EETs antagonists) to treat mouse cardiomyocytes overexpressing miR-1 and mice with myocardial infarction (MI). We found that silencing SRF attenuated the effects on miR-1 and its target genes KCNJ2 and GJA1 in the presence of t-AUCB, and inhibition of the PI3K/Akt/GSK3β pathway antagonized the effects of t-AUCB on miR-1, KCNJ2, and GJA1, which were associated with PI3Kα, Akt, and Gsk3β but not PI3Kβ or PI3Kγ. Moreover, the PI3K/Akt/GSK3β pathway was involved in the regulation of SRF by t-AUCB, and silencing SRF inhibited the t-AUCB-induced increases in Akt and Gsk3β phosphorylation. Conclusions: Both the SRF and the PI3K/Akt/GSK3β pathway are involved in the t-AUCB-mediated regulation of miR-1, and these factors interact with each other.

Multiple sclerosis is linked to MAPKERK overactivity in microglia

Reassessment of published observations in patients with multiple sclerosis (MS) suggests a microglial malfunction due to inappropriate (over)activity of the mitogen-activated protein kinase pathway ERK (MAPK^ERK). These observations regard biochemistry as well as epigenetics, and all indicate involvement of this pathway. Recent preclinical research on neurodegeneration already pointed towards a role of MAPK pathways, in particular MAPK^ERK. This is important as microglia with overactive MAPK have been identified to disturb local oligodendrocytes which can lead to locoregional demyelination, hallmark of MS. This constitutes a new concept on pathophysiology of MS, besides the prevailing view, i.e., autoimmunity. Acknowledged risk factors for MS, such as EBV infection, hypovitaminosis D, and smoking, all downregulate MAPK^ERK negative feedback phosphatases that normally regulate MAPK^ERK activity. Consequently, these factors may contribute to inappropriate MAPK^ERK overactivity, and thereby to neurodegeneration. Also, MAPK^ERK overactivity in microglia, as a factor in the pathophysiology of MS, could explain ongoing neurodegeneration in MS patients despite optimized immunosuppressive or immunomodulatory treatment. Currently, for these patients with progressive disease, no effective treatment exists. In such refractory MS, targeting the cause of overactive MAPK^ERK in microglia merits further investigation as this phenomenon may imply a novel treatment approach.

Exosomal microRNAs: Pleiotropic Impacts on Breast Cancer Metastasis and Their Clinical Perspectives

As a major threat factor for female health, breast cancer (BC) has garnered a lot of attention for its malignancy and diverse molecules participating in its carcinogenesis process. Among these complex carcinogenesis processes, cell proliferation, epithelial-to-mesenchymal transition (EMT), mesenchymal-to-epithelial transition (MET), and angiogenesis are the major causes for the occurrence of metastasis and chemoresistance which account for cancer malignancy. MicroRNAs packaged and secreted in exosomes are termed "exosomal microRNAs (miRNAs)". Nowadays, more researches have uncovered the roles of exosomal miRNAs played in BC metastasis. In this review, we recapitulated the dual actions of exosomal miRNAs exerted in the aggressiveness of BC by influencing migration, invasion, and distant metastasis. Next, we presented how exosomal miRNAs modify angiogenesis and stemness maintenance. Clinically, several exosomal miRNAs can govern the transformation between drug sensitivity and chemoresistance. Since the balance of the number and type of exosomal miRNAs is disturbed in pathological conditions, they are able to serve as instructive biomarkers for BC diagnosis and prognosis. More efforts are needed to connect the theoretical studies and clinical traits together. This review provides an outline of the pleiotropic impacts of exosomal miRNAs on BC metastasis and their clinical implications, paving the way for future personalized drugs.

Plant miR171 modulates mTOR pathway in HEK293 cells by targeting GNA12

Plant microRNAs have shown the capacity to regulate mammalian systems. The potential bioactivity of miR171vr, an isoform of the plant miR171, on human embryonic kidney 293 (HEK293) cells was investigated. Bioinformatics simulations revealed that human G protein subunit alpha 12 (GNA12) transcript could represent an excellent target for miR171vr. To confirm this prediction, in vitro experiments were performed using a synthetic microRNA designed on miR171vr sequence. MiR-treated cells showed a significant decrease of GNA12 mRNA and protein levels, confirming the putative cross-kingdom interaction. In addition, miR171vr determined the modulation of GNA12 downstream signaling factors, including mTOR, as expected. Finally, the effect of the plant miRNA on HEK293 cell growth and its stability in presence of several stressors, such as those miming digestive processes and procedures for preparing food, were evaluated. All this preliminary evidence would suggest that miR171vr, introduced by diet or as supplement in gene therapies, could potentially influence human gene expression, especially for treating disorders where GNA12 is over-expressed (i.e. oral cancer, breast and prostate adenocarcinoma) or mTOR kinase is down-regulated (e.g. obesity, type 2 diabetes, neurodegeneration).

Circular RNA hsa_circ_0001829 promotes gastric cancer progression through miR-155-5p/SMAD2 axis

Background

Accumulating evidences have shown that circular RNAs (circRNAs) play important roles in regulating the pathogenesis of cancer. However, the role of circRNAs in gastric cancer (GC) remains largely unclear.

Methods

In this study, we identified a novel upregulated circRNA, hsa_circ_0001829, in chemically induced malignant transformed human gastric epithelial cells using RNA-seq. Subsequent qRT-PCR and ISH assays were performed to detect the expression level of hsa_circ_0001829 in GC cell lines and tissues. Functional roles of hsa_circ_0001829 in GC were then explored by loss- and gain-of- function assays. Bioinformatic prediction and luciferase assay were used to investigate potential mechanisms of hsa_circ_0001829. Finally, the mice xenograft and metastasis models were constructed to assess the function of hsa_circ_0001829 in vivo.

Results

We found that hsa_circ_0001829 was significantly upregulated in GC tissues and cell lines. Loss- and gain-of- function assays showed that hsa_circ_0001829 promotes GC cells proliferation, migration and invasion, and the affected cell cycle progression and apoptosis rates may account for the effect of hsa_circ_0001829 on GC proliferation. In addition, bioinformatic prediction and luciferase assay showed that hsa_circ_0001829 acts as a molecular sponge for miR-155-5p and that SMAD2 was a target gene of miR-155-5p; moreover, hsa_circ_0001829 sponges miR-155-5p to regulate SMAD2 expression and hsa_circ_0001829 promotes GC progression through the miR-155-5p–SMAD2 pathway. Finally, suppression of hsa_circ_0001829 expression inhibited tumor growth and aggressiveness in vivo.

Conclusion

Taken together, our findings firstly demonstrated a novel oncogenic role of hsa_circ_0001829 in GC progression through miR-155-5p–SMAD2 axis, and our study may offer novel biomarkers and therapeutic targets for GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-020-01790-w.

Metformin partially reverses the inhibitory effect of co-culture with ER-/PR-/HER2+ breast cancer cells on biomarkers of monocyte antitumor activity

BACKGROUND

Immune activities of monocytes (MOs) can be altered within the microenvironment of solid malignancies, including breast cancer. Metformin (1,1-dimethylbiguanide hydrochloride, MET), has been shown to decrease tumor cell proliferation, but its effects have yet to be explored with respect to MOs (monocytes) activity during their crosstalk with breast cancer cells. Here, we investigated the effects of MET on overall phenotypic functional activities, including cellular immunometabolism and protective redox signaling based-biomarkers, intracellular free calcium ions (ifCa2+), phagocytosis and co-operative cytokines (IFN-γ and IL-10) of autologous MOs before and during their interplay with primary ER-/PR-/HER2+ breast cancer cells.

METHODS

Human primary breast cancer cells were either cultured alone or co-cultured with autologous MOs before treatment with MET.

RESULTS

MET downregulated breast cancer cell proliferation and phagocytosis, while having no significant effect on the ratio of phosphorylated Akt (p-Akt) to total Akt. Additionally, we observed that, in the absence of MET treatment, the levels of lactate dehydrogenase (LDH)-based cytotoxicity, catalase, ifCa2+, IL-10 and arginase activity were significantly reduced in co-cultures compared to levels in MOs cultured alone whereas levels of inducible nitric oxide synthase (iNOS) activity were significantly increased. In contrast, MET treatment reduced the effects measured in co-culture on the levels of LDH-based cytotoxicity, arginase activity, catalase, ifCa2+, and IFN-γ. MET also induced upregulation of both iNOS and arginase in MO cells, although the increase did not reach significant difference for iNOS activity. Moreover, MET induced a robust increase of superoxide dismutase (SOD) activity in MOs, but not in MOs co-cultured with breast cancer cells. Furthermore, MET markedly upregulated the levels of IFN-γ production and downregulated those of IL-10 in isolated MOs, while inducing a slight opposing up-regulation of IL-10 production in co-cultures.

CONCLUSIONS

Our results show that the biomarkers of phenotypic functional activities of MOs are modified after co-culturing with primary human breast cancer cells. Treatment of co-cultures with MET resulted in increased release of antitumor cytokine IFN-γ and ifCa2+, and increased cell necrosis during breast cancer cells-MOs crosstalk.

TMEM63C, a Potential Novel Target for Albuminuria Development, Is Regulated by MicroRNA-564 and Transforming Growth Factor beta in Human Renal Cells

INTRODUCTION

Transmembrane protein (TMEM) 63C is a member of the TMEM gene family and was recently linked to glomerular filtration barrier function and albuminuria. Its molecular function and expression regulation are largely unknown.

OBJECTIVE

In this study, we set out to characterize the regulating impact of microRNAs (miRNAs) such as miRNA-564 (miR-564) on TMEM63C expression in renal cells. Also, we examined the influence of transforming growth factor beta (TGF-ß) on TMEM63C expression and the potential impact of TMEM63C inhibition on epithelial-mesenchymal transition (EMT) in renal cells and on cell viability in human embryonic kidney 293 cells (HEK 293).

METHODS

Expression analyses were done using real-time PCR and Western blot. Dual luciferase assay was performed to determine the miRNA-mediated expression control. Cell viability was assessed via trypan blue exclusion staining.

RESULTS AND CONCLUSIONS

MiR-564 reduced TMEM63C expression in HEK 293 and human podocytes (hPC). The treatment of renal cells with TGF-ß led to an increased expression of TMEM63C. Moreover, a reduced TMEM63C expression was associated with a changed ratio of EMT marker proteins such as α-smooth muscle actin versus E-cadherin in HEK 293 and decreased nephrin expression in hPC. In addition, cell viability was reduced upon inhibition of TMEM63C expression in HEK 293. This study demonstrates first mechanisms involved in TMEM63C expression regulation and a link to EMT in renal cells.

miRNA expression profile changes in the peripheral blood of monozygotic discordant twins for epithelial ovarian carcinoma: potential new biomarkers for early diagnosis and prognosis of ovarian carcinoma

BACKGROUND

Ovarian cancer is the second most common gynecologic cancer with high mortality rate and generally diagnosed in advanced stages. The 5-year disease-free survival is below 40%. MicroRNAs, subset of the non-coding RNA molecules, regulate the translation in post transcriptional level by binding to specific mRNAs to promote or degrade the target oncogenes or tumor suppressor genes. Abnormal expression of miRNAs were found in numerous human cancer, including ovarian cancer. Investigating the miRNAs derived from the peripheral blood samples can be used as a marker in the diagnose, treatment and prognosis of ovarian cancer. We aimed to find biological markers for early diagnosis of ovarian cancer by investigating BRCA1 gene mutation carrier monozygotic discordant twins and their high risk healthy family individual's miRNAs.

METHODS

The study was conducted on monozygotic twins discordant for ovarian cancer, and the liquid biopsy exploration of miRNAs was performed on mononuclear cells that were isolated from the peripheral blood samples. The miRNA expression profile changes in the study were found by using microarray analysis. miRNA isolation procedure performed from the lymphocyte in accordance with the kit protocol. The presence and quality of the isolated miRNAs screened by electrophoresis. Raw data logarithmic analysis was studied by identifying the threshold, normalization, correlation, mean and median values. Target proteins were detected for each miRNA by using different algorithms.

RESULTS

After the comparison of monozygotic discordant twins for epithelial ovarian carcinoma upregulation of the 4 miRNAs, miR-6131, miR-1305, miR-197-3p, miR-3651 and downregulation of 4 miRNAs, miR-3135b, miR-4430, miR-664b-5p, miR-766-3p were found statically significant.

CONCLUSIONS

The detected 99 miRNAs out of 2549 miRNAs might be used in the clinic as new biological indicators in the diagnosis and follow up of epithelial ovarian cancer with complementary studies. The miRNA expression profiles were identified to be statistically significant in the evaluation of ovarian cancer etiology, BRCA1 mutation status, and ovarian cancer risk in accordance with the obtained data. There is a need for validation of the miRNAs which were particularly detected between monozygotic twins and its association with ovarian cancer was emphasized in our study in wider cohorts including ovarian cancer patients, and healthy individuals.

Knockdown of circ_0003340 induces cell apoptosis, inhibits invasion and proliferation through miR-564/TPX2 in esophageal cancer cells

Circular RNA (circRNA) is a promising biomarker of cancer occurrence and development. The different expression levels of circRNAs in various cancers also make them possible therapeutic targets. In this work, we researched the function and underlying mechanisms of circ_0003340 (circ3340) in esophageal cancer EC1 and EC9706 cells. Firstly, we found the expression levels of circ3340 are higher in ESCC and two esophageal cancer cells than in adjacent normal tissues and Het-1a cells. Bioinformatics analysis showed circ3340 has a binding site with miR-564. This was verified by luciferase assay, which revealed that miR-564 can be sponged by circ3340, and that the TPX2 3'UTR is a direct target of miR-564. Upregulation of miR-564 decreased TPX2 protein levels, as shown by Western blot. Moreover, knockdown of circ3340 or enhancement of miR-564 expression had similar effects in EC1 and EC9706 cells, i.e., inducing cell apoptosis, inhibiting cell proliferation, and arresting cell invasion. Downregulation of circ3340 had a negative influence on EC1 and EC9706 cells by affecting the miR-564/TPX2 pathway. Additionally, animal experiments revealed that downregulation of circ3340 inhibited tumor growth in vivo, making circ3340 a potential therapeutic target for patients with esophageal squamous cell cancer.

Role of PI3K/AKT pathway in cancer: the framework of malignant behavior

Given that the PI3K/AKT pathway has manifested its compelling influence on multiple cellular process, we further review the roles of hyperactivation of PI3K/AKT pathway in various human cancers. We state the abnormalities of PI3K/AKT pathway in different cancers, which are closely related with tumorigenesis, proliferation, growth, apoptosis, invasion, metastasis, epithelial-mesenchymal transition, stem-like phenotype, immune microenvironment and drug resistance of cancer cells. In addition, we investigated the current clinical trials of inhibitors against PI3K/AKT pathway in cancers and found that the clinical efficacy of these inhibitors as monotherapy has so far been limited despite of the promising preclinical activity, which means combinations of targeted therapy may achieve better efficacies in cancers. In short, we hope to feature PI3K/AKT pathway in cancers to the clinic and bring the new promising to patients for targeted therapies.

Dissecting miRNA facilitated physiology and function in human breast cancer for therapeutic intervention

MicroRNAs (miRNAs) are key epigenomic regulators of biological processes in animals and plants. These small non coding RNAs form a complex networks that regulate cellular function and development. MiRNAs prevent translation by either inactivation or inducing degradation of mRNA, a major concern in post-transcriptional gene regulation. Aberrant regulation of gene expression by miRNAs is frequently observed in cancer. Overexpression of various 'oncomiRs' and silencing of tumor suppressor miRNAs are associated with various types of human cancers, although overall downregulation of miRNA expression is reported as a hallmark of cancer. Modulations of the total pool of cellular miRNA by alteration in genetic and epigenetic factors associated with the biogenesis of miRNA machinery. It also depends on the availability of cellular miRNAs from its store in the organelles which affect tumor development and cancer progression. Here, we have dissected the roles and pathways of various miRNAs during normal cellular and molecular functions as well as during breast cancer progression. Recent research works and prevailing views implicate that there are two major types of miRNAs; (i) intracellular miRNAs and (ii) extracellular miRNAs. Concept, that the functions of intracellular miRNAs are driven by cellular organelles in mammalian cells. Extracellular miRNAs function in cell-cell communication in extracellular spaces and distance cells through circulation. A detailed understanding of organelle driven miRNA function and the precise role of extracellular miRNAs, pre- and post-therapeutic implications of miRNAs in this scenario would open several avenues for further understanding of miRNA function and can be better exploited for the treatment of breast cancers.

MicroRNA-4500 Inhibits Migration, Invasion, and Angiogenesis of Breast Cancer Cells via RRM2-Dependent MAPK Signaling Pathway

With the consideration of the dynamic role of microRNAs (miRNAs) in breast cancer, miRNAs may serve as therapeutic targets, helping to prevent development of therapy resistance, maintain stable disease, and prohibit metastatic spread. We identified the differentially expressed breast cancer-related gene ribonucleotide reductase subunit M2 (RRM2) as the study focus through microarray expression profiles. Next, the upstream regulatory microRNA (miR)-4500 of RRM2 was predicted using bioinformatics website analysis, and their binding was verified by a dual luciferase reporter gene assay. The regulatory effects of miR-4500 on breast cancer cell proliferation, apoptosis, migration, invasion, and capillary-like tube formation of endothelial cells were assessed by gain- and loss-of-function experiments. The experimental data revealed that miR-4500 was downregulated, whereas RRM2 was upregulated in breast cancer cells. Mechanistic analysis revealed that miR-4500 downregulated the RRM2 expression to inactivate the mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, miR-4500 exerted anti-tumor effects by targeting RRM2 through suppression of the MAPK signaling pathway in vitro, evidenced by attenuated cancer cell migration and invasion and capillary-like tube formation of endothelial cells. The in vivo experiments further corroborated in vitro results. Collectively, overexpressed miR-4500 could downregulate RRM2 and inhibit activation of the MAPK signaling pathway, thus attenuating breast cancer cell proliferation, invasion, migration, and angiogenesis and promoting breast cancer cell apoptosis.

NF-κB-Induced Upregulation of miR-548as-3p Increases Invasion of NSCLC by Targeting PTEN

BACKGROUND

Non-Small Cell Lung Cancer (NSCLC) is an aggressive cancer type due to high metastatic capacity. Nuclear Factor Kappa B (NF-κB) is a consistently active transcription factor in malignant lung cancer cells and has crucial significance in NSCLC progression. It is also implicated in the transcriptional regulation of many genes including microRNAs (miRNAs) that function as tumor suppressor or oncogene. It has been increasingly reported that several miRNAs defined as gene members are induced by NF-κB. The present study aimed to find novel miRNAs that are regulated by NF-κB.

METHODS

Chromatin İmmunoprecipitation Sequencing (ChIP-Seq) experiment and bioinformatic analysis were used to determine NF-κB-dependent miRNAs. Western blot analysis, quantitative real-time polymerase chain reaction (qRT-PCR), luciferase reporter gene assays were carried out to investigate the target genes of miRNAs. To determine biologic activity, transwell invasion and MTT assay were carried out on H1299 NSCLC cell line. miRNA expression level was evaluated in metastatic and non-metastatic tissue samples of NSCLC patients.

RESULTS

ChIP-Seq and qRT-PCR experiments showed that miR-548as-3p is transcriptionally regulated by NF- κB in response to Tumor Necrosis Factor-α (TNF-α) treatment. Then, we found that tumor suppressor Phosphatase and Tension homolog (PTEN) is a direct target of miR-548as-3p. Furthermore, miR-548as-3p mediates phosphatidylinositol-3-OH kinase (PI3K)/Akt pathway and NF-κB-implicated genes including Matrix Metalloproteinases 9 (MMP9), Slug and Zeb1. We further showed that miR-548as-3p increased invasiveness of NSCLC cells and was upregulated in metastatic tumor tissues compared to non-metastatic ones.

CONCLUSION

All these findings provide a miRNAs-mediated novel mechanism for NF-κB signaling and that miR-548as-3p could be a biomarker for NSCLC metastasis.

Role of regulatory miRNAs of the PI3K/AKT signaling pathway in the pathogenesis of breast cancer

Breast cancer is one of the most common tumors in women. Current data indicate that the overexpression of some microRNAs (miRNAs) is associated with breast cancer, in relation to stage, tumor size and potential for metastasis. Some studies have reported that miRNAs have critical roles in cellular processes implicated in breast cancer cell growth, migration and metastasis by targeting the PI3K/AKT oncogenic signaling pathway. Therefore, identifying novel regulatory miRNAs for this oncogenic pathway and discovery of their related target genes may represent a promising therapeutic approach for breast cancer therapy. This review highlights the recent findings about the potential role of PI3K/AKT signaling regulatory miRNAs in breast cancer tumorigenesis.

miR-601 inhibits proliferation, migration and invasion of prostate cancer stem cells by targeting KRT5 to inactivate the Wnt signaling pathway

OBJECTIVE

This study aimed to verify the hypothesis that downregulation of miR-601 inhibits the proliferation, migration, and invasion of prostate cancer stem cells (PCSCs) by the Wnt signaling pathway through targeting keratin 5 (KRT5).

METHODS

Bioinformatic tools were applied to predict miRNAs and genes potentially associated with prostate cancer, then miR-601 and KRT5 were selected. Subsequently, PCSCs were investigated with respect to miR-601 overexpression or inhibition, KRT5 overexpression, or treatment with a Wnt pathway inhibitor. A series of experiments including western blotting, RT-qPCR, wound healing experiment, transwell assay, MTT assay, annexin V-FITC/PI flow cytometric analysis, nude mice assay and immunohistochemistry were then carried out.

RESULTS

Compared with negative control group, migration, invasion, and proliferation of PCSCs and Wnt-1 expression were all enhanced, but apoptosis was attenuated in the miR-601 mimic group. Furthermore, results identified in the other groups (KRT5, miR-601 inhibitor, miR-601 inhibitor + KRT5, Wnt signaling pathway inhibitor, PRI-724/PRI-724 + KRT5) were opposite to those identified with the miR-601 mimic group (all P<0.05). Compared with the miR-601 inhibitor + KRT5 group, migration, invasion, and proliferation of PCSCs and Wnt-1 expression were all increased, whereas apoptosis was suppressed in KRT5 or miR-601 inhibitor groups (all P<0.05). Compared with the PRI-724 + KRT5 group, migration, invasion, and proliferation of PCSCs and Wnt-1 expression were also enhanced, whereas apoptosis was inhibited in PRI-724 or KRT5 groups (all P<0.05).

CONCLUSION

Results obtained from the present study have demonstrated that downregulation of miR-601 is able to inhibit the proliferation, migration, and invasion of PCSCs by activating KRT5, and subsequently inhibiting the Wnt pathway.

Amyloid precursor protein promotes the migration and invasion of breast cancer cells by regulating the MAPK signaling pathway

To verify whether amyloid precursor protein (APP) affects the migration and invasion of breast cancer cell lines, and to understand its underlying mechanisms, epithelial-mesenchymal transition (EMT), the mitogen-activated protein kinase (MAPK) signaling pathway and the matrix metalloproteinase (MMP) family were investigated in MDA-MB-231, MCF-7 and BT474 human breast cancer cells. Breast cancer cell lines were transfected with plasmids containing APP coding sequences (pEGFP-n1-APP) and APP short hairpin RNA (pENTR APP shRNA). APP overexpres-sion efficiency, knockout efficiency and the expression levels of related genes were tested using reverse transcription-quantitative PCR (RT-qPCR) and western blot analyses. The effects of APP and mitogen-activated protein kinase kinase (MEK) inhibitor on cell migration and invasion were examined using Transwell assays. The results demonstrated that APP was significantly upregulated in the pEGFP-n1-APP group (P<0.05), and significantly downregulated in the pENTR APP shRNA group (P<0.05), compared with the control group. APP overexpression increased the migratory and invasive ability of human breast cancer cells (P<0.05), whereas APP silencing significantly inhibited cell migration and invasion (P<0.05). RT-qPCR and western blot analysis results suggested that APP overexpression significantly increased the expression of MMP-9, MMP-2, MMP-3, N-cadherin and vimentin (P<0.05). In addition, the enhanced expression of APP markedly affected the phosphorylation of mitogen-activated protein kinase kinase kinase 11 (MLK3), mitogen-activated protein kinase kinase 4 (MEK4) and mitogen-activated protein kinase 10 (JNK3; P<0.05). Additionally, APP overexpression had no effect on the total expression levels of MLK3, MEK4, and JNK3; however, APP overexpression significantly decreased the expression levels of E-cadherin and cytokeratin (P<0.05). Conversely, APP silencing had the opposite effects. When cells were treated with the MEK inhibitor PD0325901, the expression of APP was not altered, nor was the expression levels of MEK and its upstream signaling molecules. Taken together, the present findings suggested that APP could affect the migration and invasion of human breast cancer cells by mediating the activation of the MAPK signaling pathway, thereby promoting the EMT process.

mTOR/HDAC1 Crosstalk Mediated Suppression of ADH1A and ALDH2 Links Alcohol Metabolism to Hepatocellular Carcinoma Onset and Progression in silico

Hepatocellular carcinoma (HCC) is ranked the third deadliest cancer worldwide whose molecular pathogenesis is not fully understood. Although deregulated metabolic pathways have been implicated in HCC onset and progression, the mechanisms triggering this metabolic imbalance are yet to be explored. Here, we identified a gene signature coding catabolic enzymes (Cat-GS) involved in key metabolic pathways like amino acid, lipid, carbohydrate, drug, and retinol metabolism as suppressed in HCC. A higher expression of deregulated Cat-GS is associated with good survival and less aggressive disease state in HCC patients. On the other hand, we identified mTOR signaling as a key determinant in HCC onset and progression, whose hyperactivation is found associated with poor survival and aggressive disease state in HCC patients. Next, out of Cat-GS, we established two key regulators of alcohol metabolism, alcohol dehydrogenase 1A (ADH1A) and aldehyde dehydrogenase 2 (ALDH2), as being transcriptionally suppressed by histone deacetylase 1 (HDAC1) at the downstream of mTORC1 signaling. Suppressed ADH1A and ALDH2 expression aligns well with HCC-specific molecular profile and can efficiently predict disease onset and progression, whereas higher ADH1A and ALDH2 expression is associated with good survival and less aggressive disease state in HCC patients. Overall, our in silico findings suggest that transcriptional suppression of alcohol metabolism regulators, ADH1A and ALDH2, at the downstream of mTOR signaling is, in part, responsible for triggering oncogenic transformation of hepatocytes resulting in disease onset and progression in HCC.

microRNA-564 inhibits the aggressive phenotypes of papillary thyroid cancer by directly targeting astrocyte-elevated gene-1

Background: Accumulating evidence has revealed that an increasing number of microRNAs (miRNAs) are dysregulated in papillary thyroid cancer (PTC) and that their dysregulation plays an important role in PTC onset and progression. Reportedly, miRNA-564 (miR-564) is downregulated in several types of human cancer. However, its expression profile and specific functions in PTC remain unclear to date. Methods: In this study, we used reverse transcription-quantitative polymerase chain reaction to detect miR-564 expression in PTC tissues and cell lines. Further, the regulatory roles of miR-564 in the malignant development of PTC in vitro and in vivo were examined using a series of functional experiments. In addition, the possible underlying mechanisms and signaling pathways involved were investigated. Results: We demonstrated that miR-564 expression markedly decreased in PTC tissues and cell lines, and this decrease correlated with the lymph node metastasis and tumor-node-metastasis stage. miR-564 upregulation significantly inhibited cell proliferation, migration, and invasion and induced cell apoptosis in vitro as well as hindered tumor growth in vivo. Furthermore, astrocyte-elevated gene-1 (AEG-1) was identified as a direct target gene of miR-564 in PTC cells. Its expression was upregulated and inversely correlated with miR-564 expression in clinically PTC tissues. Additionally, the silencing of AEG-1 expression could imitate the action of miR-564 overexpression in PTC cells. Remarkably, the restoration of AEG-1 expression partially abolished the tumor-suppressing effects induced by a miR-564 upregulation in PTC cells. Ectopic miR-564 expression deactivated the PTEN/Akt pathway in PTC cells in vitro and in vivo. Conclusion: Overall, the findings of the current study suggest that miR-564 is a tumor-suppressive miRNA that exerts crucial roles in the development and progression of PTC. Therefore, this miRNA might be a promising candidate target in the anticancer treatment of patients with PTC.

ITGA6 and RPSA synergistically promote pancreatic cancer invasion and metastasis via PI3K and MAPK signaling pathways

Pancreatic cancer is one of the most malignant tumors. Invasion and metastasis can occur in the early stage of pancreatic cancer, contributing to the poor prognosis. Accordingly, in this study, we evaluated the molecular mechanisms underlying invasion and metastasis. Using mass spectrometry, we found that Integrin alpha 6 (ITGA6) was more highly expressed in a highly invasive pancreatic cancer cell line (PC-1.0) than in a less invasive cell line (PC-1). Through in vitro and in vivo experiments, we observed significant decreases in invasion and metastasis in pancreatic cancer cells after inhibiting ITGA6. Based on data in TCGA, high ITGA6 expression significantly predicted poor prognosis. By using Co-IP combined mass spectrometry, we found that ribosomal protein SA (RPSA), which was also highly expressed in PC-1.0, interacted with ITGA6. Similar to ITGA6, high RPSA expression promoted invasion and metastasis and indicated poor prognosis. Interestingly, although ITGA6 and RPSA interacted, they did not mutually regulate each other. ITGA6 and RPSA affected invasion and metastasis via the PI3K and MAPK signaling pathways, respectively. Inhibiting ITGA6 significantly reduced the expression of p-AKT, while inhibiting RPSA led to the downregulation of p-ERK1/2. Compared with the inhibition of ITGA6 or RPSA alone, the downregulation of both ITGA6 and RPSA weakened invasion and metastasis to a greater extent and led to the simultaneous downregulation of p-AKT and p-ERK1/2. Our research indicates that the development of drugs targeting both ITGA6 and RPSA may be an effective strategy for the treatment of pancreatic cancer.

The clinical significance of CHEK1 in breast cancer: a high-throughput data analysis and immunohistochemical study

Breast cancer (BC) is a kind of malignant cancer that seriously threatens women's health. Research scientists have found that BC occurs as the result of multiple effects of the external environment and internal genetic changes. Cell cycle checkpoint kinase 1 (CHEK1) is a crucial speed limit point in the cell cycle. Alterations of CHEK1 have been found in various tumors but are rarely reported or verified in BC. By mining database information, a large amount of mRNA and protein data was collected and meta-analyzed. Also, in-house immunohistochemistry was carried out to validate the results of the CHEK1 expression levels. Relative clinical features of BC patients were calculated with the CHEK1 expression levels to determine their diagnostic value. The mRNA levels of CHEK1 were higher in 1,089 cases of BC tissues than in 291 cases of non-BC tissues. We observed that the mRNA levels of CHEK1 are related to the clinical stages of BC patients (P = 0.008) and are also significant for overall survival (HR = 1.6, P = 0.0081). Using the immunohistochemistry method, we calculated and confirmed, using Fisher's exact test (P < 0.001), that a high-level CHEK1 protein is exhibited in BC tissues. Overexpressed CHEK1 mRNA promotes the occurrence of BC. Also, up-regulated CHEK1 could serve as an independent risk biomarker in BC patients' prognoses.

Oncogenic and Tumor-Suppressive Roles of MicroRNAs with Special Reference to Apoptosis: Molecular Mechanisms and Therapeutic Potential

MicroRNAs (miRNAs) are the non-coding class of minute RNA molecules that negatively control post-transcriptional regulation of various functional genes. These miRNAs are transcribed from the loci present in the introns of functional or protein-coding genes, exons of non-coding genes, or even in the 3'-untranslated region (3'-UTR). They have potential to modulate the stability or translational efficiency of a variety of target RNA [messenger RNA (mRNA)]. The regulatory function of miRNAs has been elucidated in several pathological conditions, including neurological (Alzheimer's disease and Parkinson's disease) and cardiovascular conditions, along with cancer. Importantly, miRNA identification in cancer progression and invasion has evolved as an incipient era in cancer treatment. Several studies have shown the influence of miRNAs on various cancer processes, including apoptosis, invasion, metastasis and angiogenesis. In particular, apoptosis induction in tumor cells through miRNA has been extensively studied. The biphasic mode (up- and down-regulation) of miRNA expression in apoptosis and other cancer processes has already been determined. The findings of these studies could be utilized to develop potential therapeutic strategies for the management of various cancers. The present review critically describes the oncogenic and tumor suppressor role of miRNAs in apoptosis and other cancer processes, therapy resistance, and use of their presence in the body fluids as biomarkers.

Novel tumor suppressor SPRYD4 inhibits tumor progression in hepatocellular carcinoma by inducing apoptotic cell death

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated deaths worldwide. Although recent studies have proposed different biomarkers for HCC progression and therapy resistance, a better understanding of the molecular mechanisms underlying HCC progression and recurrence, as well as the identification of molecular markers with a higher diagnostic accuracy, are necessary for the development of more effective clinical management strategies. Here, we aimed to identify novel players in HCC progression.

METHODS

SPRYD4 mRNA and protein expression analyses were carried out on a normal liver-derived cell line (HL-7702) and four HCC-derived cell lines (HepG2, SMMC7721, Huh-7, BEL-7402) using qRT-PCR and Western blotting, respectively. Cell proliferation Cell Counting Kit-8 (CCK-8) assays, protein expression analyses for apoptosis markers using Western blotting, and Caspase-Glo 3/7 apoptosis assays were carried out on the four HCC-derived cell lines. Expression comparison, functional annotation, gene set enrichment, correlation and survival analyses were carried out on patient data retrieved from the NCBI Gene module, the NCBI GEO database and the TCGA database.

RESULTS

Through a meta-analysis we found that the expression of SPRYD4 was downregulated in primary HCC tissues compared to non-tumor tissues. We also found that the expression of SPRYD4 was downregulated in HCC-derived cells compared to normal liver-derived cells. Subsequently, we found that the expression of SPRYD4 was inversely correlated with a gene signature associated with HCC cell proliferation. Exogenous SPRYD4 expression was found to inhibit HCC cell proliferation by inducing apoptotic cell death. We also found that SPRYD4 expression was associated with a good prognosis and that its expression became downregulated when HCCs progressed towards more aggressive stages and higher grades. Finally, we found that SPRYD4 expression may serve as a biomarker for a good overall and relapse-free survival in HCC patients.

CONCLUSIONS

Our data indicate that a decreased SPRYD4 expression may serve as an independent predictor for a poor prognosis in patients with HCC and that increased SPRYD4 expression may reduce HCC growth and progression through the induction of apoptotic cell death, thereby providing a potential therapeutic target.

Discovering lncRNA mediated sponge interactions in breast cancer molecular subtypes

BACKGROUND

Long non-coding RNAs (lncRNAs) can indirectly regulate mRNAs expression levels by sequestering microRNAs (miRNAs), and act as competing endogenous RNAs (ceRNAs) or as sponges. Previous studies identified lncRNA-mediated sponge interactions in various cancers including the breast cancer. However, breast cancer subtypes are quite distinct in terms of their molecular profiles; therefore, ceRNAs are expected to be subtype-specific as well.

RESULTS

To find lncRNA-mediated ceRNA interactions in breast cancer subtypes, we develop an integrative approach. We conduct partial correlation analysis and kernel independence tests on patient gene expression profiles and further refine the candidate interactions with miRNA target information. We find that although there are sponges common to multiple subtypes, there are also distinct subtype-specific interactions. Functional enrichment of mRNAs that participate in these interactions highlights distinct biological processes for different subtypes. Interestingly, some of the ceRNAs also reside in close proximity in the genome; for example, those involving HOX genes, HOTAIR, miR-196a-1 and miR-196a-2. We also discover subtype-specific sponge interactions with high prognostic potential. We found that patients differ significantly in their survival distributions if they are group based on the expression patterns of specific ceRNA interactions. However, it is not the case if the expression of individual RNAs participating in ceRNA is used.

CONCLUSION

These results can help shed light on subtype-specific mechanisms of breast cancer, and the methodology developed herein can help uncover sponges in other diseases.

SIK2 attenuates proliferation and survival of breast cancer cells with simultaneous perturbation of MAPK and PI3K/Akt pathways

Salt Inducible Kinase2 (SIK2) has been shown to contribute to tumorigenesis in multiple tumor types in a dichotomous manner. However, little is known about its contribution to breast malignancies. Here, we report SIK2 as a potential tumor suppressor in breast cancer whose expression was reduced in tumor tissues and breast cancer cell lines compared to normal counterparts. In vitro loss- and gain-of-function experiments combined with xenograft studies demonstrated that SIK2-mediated attenuation of proliferation and survival of breast cancer cells with parallel inhibition of both Ras/Erk and PI3K/Akt pathways. Our findings elucidated that SIK2 has also an inhibitory role in migration/invasion ability of breast cancer cells through regulation of epithelial mesenchymal transition. Immunostaining of patient tumors revealed that SIK2 protein level is frequently downregulated in invasive mammary carcinomas and negatively correlated with the mitotic activity of the cells in triple negative breast cancers and hormone positive tumors. Strikingly, patient survival analysis indicated that higher levels of SIK2 are significantly associated with better survival, especially in basal breast cancer cases. Overall, our findings suggest SIK2 as a potential tumor suppressor in the control of breast tumorigenesis, at least in part, via inhibiting PI3K/Akt and Ras/ERK signaling cascades simultaneously and a novel prognostic marker, especially in basal subtypes of breast cancer.

Lipid nanoparticle siRNA cocktails for the treatment of mantle cell lymphoma

Mantle cell lymphoma is an aggressive and incurable subtype of non‐Hodgkin B cell lymphoma. Patients typically present with advanced disease, and most patients succumb within a decade of diagnosis. There is a clear and urgent need for novel therapeutic approaches that will affect mantle cell lymphoma through a unique mechanism compared to current therapies. This study examined the use of RNA interference (RNAi) therapy to attack mantle cell lymphoma at the mRNA level, silencing genes associated with cancer cell proliferation. We identified a lipid nanoparticle formulated with the lipidoid 306O₁₃ that delivered siRNA to JeKo‐1 and MAVER‐1 mantle cell lymphoma cell lines. Three therapeutic gene targets were examined for their effect on lymphoma growth. These included Cyclin D1, which is a cell cycle regulator, as well as Bcl‐2 and Mcl‐1, which prevent apoptosis. Gene knockdown with siRNA doses as low at 10 nM increased lymphoma cell apoptosis without carrier‐mediated toxicity. Silencing of Cyclin D1 induced apoptosis despite a twofold “compensation” upregulation of Cyclin D2. Upon simultaneous silencing of all three genes, nearly 75% of JeKo‐1 cells were apoptosing 3 days post‐transfection. Furthermore, cells proliferated at only 15% of their pretreatment rate. These data suggest that lipid nanoparticles‐formulated, multiplexed siRNA “cocktails” may serve as a beneficial addition to the treatment regimens for mantle cell lymphoma and other aggressive cancers.

Targeting PLK1 overcomes T-DM1 resistance via CDK1-dependent phosphorylation and inactivation of Bcl-2/xL in HER2-positive breast cancer

Trastuzumab-refractory, HER2 (human epidermal growth factor receptor 2)-positive breast cancer is commonly treated with trastuzumab emtansine (T-DM1), an antibody-drug conjugate of trastuzumab and the microtubule-targeting agent, DM1. However, drug response reduces greatly over time due to acquisition of resistance whose molecular mechanisms are mostly unknown. Here, we uncovered a novel mechanism of resistance against T-DM1 by combining whole transcriptome sequencing (RNA-Seq), proteomics and a targeted small interfering RNA (siRNA) sensitization screen for molecular level analysis of acquired and de novo T-DM1-resistant models of HER2-overexpressing breast cancer. We identified Polo-like kinase 1 (PLK1), a mitotic kinase, as a resistance mediator whose genomic as well as pharmacological inhibition restored drug sensitivity. Both acquired and de novo resistant models exhibited synergistic growth inhibition upon combination of T-DM1 with a selective PLK1 inhibitor, volasertib, at a wide concentration range of the two drugs. Mechanistically, T-DM1 sensitization upon PLK1 inhibition with volasertib was initiated by a spindle assembly checkpoint (SAC)-dependent mitotic arrest, leading to caspase activation, followed by DNA damage through CDK1-dependent phosphorylation and inactivation of Bcl-2/xL. Furthermore, we showed that Ser70 phosphorylation of Bcl-2 directly regulates apoptosis by disrupting the binding to and sequestration of the pro-apoptotic protein Bim. Importantly, T-DM1 resistance signature or PLK1 expression correlated with cell cycle progression and DNA repair, and predicted a lower sensitivity to taxane/trastuzumab combination in HER2-positive breast cancer patients. Finally, volasertib in combination with T-DM1 greatly synergized in models of T-DM1 resistance in terms of growth inhibition both in three dimensional (3D) cell culture and in vivo. Altogether, our results provide promising pre-clinical evidence for potential testing of T-DM1/volasertib combination in T-DM1 refractory HER2-positive breast cancer patients for whom there is currently no treatment available.

The MAPK-Signaling Pathway in Colorectal Cancer: Dysregulated Genes and Their Association With MicroRNAs

Mitogen-activated protein kinase (MAPK) pathways regulate many cellular functions including cell proliferation and apoptosis. We examined associations of differential gene and microRNA (miRNA) expression between carcinoma and paired normal mucosa for 241 genes in the KEGG-identified MAPK-signaling pathway among 217 colorectal cancer (CRC) cases. Gene expression data (RNA-Seq) and miRNA expression data (Agilent Human miRNA Microarray V19.0; Agilent Technologies Inc., Santa Clara, CA, USA) were analyzed. We first identified genes most strongly associated with CRC using a fold change (FC) of >1.50 or <0.67) that were statistically significant after adjustment for multiple comparisons. We then determined miRNAs associated with dysregulated genes and through miRNA:mRNA (messenger RNA) seed region matches discerned genes with a greater likelihood of having a direct biological association. Ninety-nine genes had a meaningful FC for all CRC, microsatellite unstable–specific tumors, or microsatellite stable–specific tumors. Thirteen dysregulated genes were associated with miRNAs, totaling 68 miRNA:mRNA associations. Thirteen of the miRNA:mRNA associations had seed region matches where the differential expression between the miRNA and mRNA was inversely related suggesting a direct association as a result of their binding. Several direct associations, upstream of ERK1/ERK2, JNK, and p38, were found for PDGFRA with 7 miRNAs; RASGRP3 and PRKCB with miR-203a; and TGFBR1 with miR-6071 and miR-2117. Other associations between miRNAs and mRNAs are most likely indirect, resulting from feedback and feed forward loops. Our results suggest that miRNAs may alter MAPK signaling through direct binding with key genes in this pathway. We encourage others to validate results in targeted CRC experiments that can help solidify important therapeutic targets.

Manganese-12 acetate suppresses the migration, invasion, and epithelial-mesenchymal transition by inhibiting Wnt/β-catenin and PI3K/AKT signaling pathways in breast cancer cells

BACKGROUND

Breast cancer is the leading cause of cancer-related death in the world, and it is of great value to reveal the molecular mechanisms of breast cancer progression and develop new therapeutic targets.

METHODS

Transwell assay is used to analyze the migration and invasion of breast cancer cells. Real-time PCR and western blotting assay are applied to detect the expression levels of epithelial-mesenchymal transition markers and the key members of Wnt/β-catenin and PI3K/AKT signaling pathways.

RESULTS

Manganese-12 acetate (Mn12Ac) significantly inhibited the migration and invasion of MCF7 and MDA-MB-231 breast cancer cells. Western blotting assay further showed that Mn12Ac significantly upregulated E-cadherin, and downregulated N-cadherin and vimentin. We further found that Mn12Ac reduced the mRNA expressions of epithelial-mesenchymal transition-associated transcription factors snail, slug, twist1, and ZEB1 using real-time PCR assay. Importantly, we further found that Mn12Ac significantly reduced the Wnt1 and β-catenin protein expressions, and suppressed the phosphorylation of PI3K and AKT in MCF7 and MDA-MB-231 breast cancer cells. Very interestingly, we also showed that Mn12Ac decreased the mRNA and protein expressions of programmed cell death ligand 1.

CONCLUSION

Taken together, our results suggested that Mn12Ac inhibited the migration, invasion, and epithelial-mesenchymal transition by regulating Wnt/β-catenin and PI3K/AKT signaling pathways in breast cancer.

MiR-564 is down-regulated in osteosarcoma and inhibits the proliferation of osteosarcoma cells via targeting Akt

Aberrant expression of miRNAs has been observed in a variety of human cancers. In this study, we reported that miR-564 was down-regulated in human osteosarcoma (OS) cell lines and patients. Overexpression of miR-564 in OS cells suppressed the cell proliferation and induced cell apoptosis. Mechanistically, we identified Akt as a direct target of miR-564. Highly expressed miR-564 decreased the expression of Akt at both mRNA and protein level and consequently, inhibited the essential role of Akt in the glycolysis of OS cells. Notably, restoring the expression of Akt in miR-564 overexpressing cells recovered the glucose metabolism and cell growth. These results suggested that miR-564 inhibited the glycolysis and cell proliferation through directly targeting Akt, which highlighted the potential application of miR-564-Akt axis in the treatment of osteosarcoma.

MiR-30e inhibits tumor growth and chemoresistance via targeting IRS1 in Breast Cancer

MicroRNA-30e (miR-30e) is downregulated in various tumor types. However, its mechanism in inhibiting tumor growth of breast cancer remains to be elucidated. In this study, we found that miR-30e was significantly downregulated in tumor tissues of breast cancer (BC) patients and cell lines, and overexpression of miR-30e inhibited cell proliferation, migration and invasion. To understand the potential mechanism of miR-30e in inhibiting tumor growth, we showed that miR-30e blocked the activation of AKT and ERK1/2 pathways, and the expression of HIF-1α and VEGF via directly targeting IRS1. Moreover, miR-30e regulates cell proliferation, migration, invasion and increases chemosensitivity of MDA-MB-231 cells to paclitaxel by inhibiting its target IRS1. MiR-30e also inhibited tumor growth and suppressed expression of IRS1, AKT, ERK1/2 and HIF-1α in mouse xenograft tumors. To test the clinical relevance of these results, we used 40 pairs of BC tissues and adjacent normal tissues, analyzed the levels of miR-30e and IRS1 expression in these tissues, and found that miR-30e levels were significantly inversely correlated with IRS1 levels in these BC tissues, suggesting the important implication of our findings in translational application for BC diagnostics and treatment in the future.

miR-564 inhibits hepatocellular carcinoma cell proliferation and invasion by targeting the GRB2-ERK1/2-AKT axis

Recent studies have shown that miR-564 is closely related to the development of various tumors, including breast cancer, lung cancer and glioma. However, few studies have examined miR-564 in hepatocellular carcinoma (HCC). Here, we demonstrated that miR-564 expression in HCC tissues was lower than that in adjacent noncancerous tissues and that miR-564 expression was associated with tumor size, tumor number and vein invasion. Bioinformatics analyses showed that low levels of miR-564 were correlated with poor prognosis. Furthermore, upregulation of miR-564 impaired SMCC7721 and MHCC97H cell proliferation, migration and invasion in vitro and reduced tumorigenesis in vivo. Next, we found that GRB2 was a direct target gene of miR-564 in the HCC cell lines. GRB2 was highly expressed in HCC tissues and negatively correlated with miR-564 expression levels. When GRB2 was downregulated by GRB2-siRNA, HCC cell proliferation, invasion and metastasis were impaired, and restoring GRB2 expression partially reversed the inhibitory effects of miR-564. Western blot analysis showed that miR-564 overexpression reduced GRB2 expression in HCC cell lines and inhibited ERK1/2 and AKT phosphorylation. miR-564 overexpression also upregulated the epithelial-like cell marker E-cadherin and downregulated the interstitial cell-like markers N-cadherin and vimentin. These results suggest that miR-564 inhibits the malignant phenotype of HCC cells by targeting the GRB2-ERK1/2-AKT axis. Consequently, miR-564 may be used as a prognostic marker and therapeutic target for HCC.

MicroRNA‑3666 inhibits breast cancer cell proliferation by targeting sirtuin 7

The abnormal expression of microRNAs (miRNAs) is associated with cancer initiation and progression. miRNAs functioning as oncogenes or tumor suppressors represent novel biomarkers for cancer diagnosis, prognosis, and serve as therapeutic tools. MiR‑3666 has been reported as a tumor suppressor in various types of cancer; however, its role in breast cancer remains unknown. In the current study, the aim was to investigate the potential role of miR‑3666 in breast cancer. It was identified that miR‑3666 was decreased in breast cancer cell lines and that the overexpression of miR‑3666 inhibited breast cancer cell proliferation. Furthermore, miR‑3666 promotes cell apoptosis of breast cancer cells. Bioinformatics analysis and dual‑luciferase reporter assay demonstrated that miR‑3666 targeted the 3'‑untranslated region of sirtuin 7 (SIRT7) which was recognized as an oncogene. Overexpression of miR‑3666 decreased SIRT7 expression levels, and knockdown of SIRT7 suppressed proliferation and promoted apoptosis of breast cancer cells. A rescue assay demonstrated that the restoration of SIRT7 expression markedly reversed the miR‑3666‑induced anti‑tumor effects. Thus, the current study indicates that miR‑3666 suppresses breast cancer cell proliferation by targeting SIRT7, and propose miR‑3666 as a potential candidate for breast cancer therapy.

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.

Combined inhibition of AKT and HSF1 suppresses breast cancer stem cells and tumor growth

Breast cancer is the most common cancer in women and the second leading cause of cancer deaths in women. Over 90% of breast cancer deaths are attributable to metastasis. Our lab has recently reported that AKT activates heat shock factor 1 (HSF1), leading to epithelial-to-mesenchymal transition in HER2-positive breast cancer. However, it is unknown whether the AKT-HSF1 pathway plays an important role in other breast cancer subtypes, breast cancer stem cells, or breast cancer growth and metastasis. Herein, we showed AKT and HSF1 to be frequently co-activated in breast cancer cell lines and specimens across different subtypes. Activated AKT (S473) and HSF1 (S326) are strongly associated with shortened time to metastasis. Inhibition of the AKT-HSF1 signaling axis using small molecule inhibitors, HSF1 knockdown or the dominant-negative HSF1 mutant (S326A) reduced the growth of metastatic breast cancer cells and breast cancer stem cells. The combination of small molecule inhibitors targeting AKT (MK-2206) and HSF1 (KRIBB11) resulted in synergistic killing of breast cancer cells and breast cancer stem cells across different molecular subtypes. Using an orthotopic xenograft mouse model, we found that combined targeting of AKT and HSF1 to significantly reduce tumor growth, induce tumor apoptosis, delay time to metastasis, and prolong host survival. Taken together, our results indicate AKT-HSF1 signaling mediates breast cancer stem cells self-renewal, tumor growth and metastasis, and that dual targeting of AKT and HSF1 resulted in synergistic suppression of breast cancer progression thereby supporting future testing of AKT-HSF1 combination therapy for breast cancer patients.