Metformin Treatment Suppresses Melanoma Cell Growth and Motility Through Modulation of microRNA Expression

Metformin regulates the proliferation and motility of melanoma cells by modulating the LINC00094/miR-1270 axis

BACKGROUND

Melanoma is an aggressive tumor with a high mortality rate. Metformin, a commonly prescribed diabetes medication, has shown promise in cancer prevention and treatment. Long noncoding RNAs (lncRNAs) are non-protein-coding RNA molecules that play a key role in tumor development by interacting with cellular chromatins. Despite the benefits of metformin, the anticancer mechanism underlying its effect on the regulation of lncRNAs in melanoma remains unclear.

METHODS

We investigated the lncRNA profiles of human melanoma cells with and without metformin treatment using a next-generation sequencing approach (NGS). Utilizing public databases, we analyzed the expression levels and clinical impacts of LINC00094 and miR-1270 in melanoma. The expression levels of LINC00094 and miR-1270 were verified in human cell lines and clinical samples by real-time PCR and in situ hybridization. The biological roles of LINC00094 and miR-1270 in cell growth, proliferation, cell cycle, apoptosis, and motility were studied using in vitro assays.

RESULTS

We identify a novel long noncoding RNA, namely LINC00094, whose expression considerably decreased in melanoma cells after metformin treatment. In situ hybridization analysis revealed substantially higher expression of LINC00094 in cutaneous melanoma tissue compared with adjacent normal epidermis and normal control tissues (P < 0.001). In nondiabetic patients with melanoma, the overall survival of high LINC00094 expression group was shorter than the low LINC00094 expression group with borderline statistical significance (log-rank test, P = 0.057). Coexpression analysis of LINC00094 indicated its involvement in the mitochondrial respiratory pathway, with its knockdown suppressing genes associated with mitochondrial oxidative phosphorylation, glycolysis, antioxidant production, and metabolite levels. Functional analysis revealed that silencing-LINC00094 inhibited the proliferation, colony formation, invasion, and migration of melanoma cells. Cell cycle analysis following LINC00094 knockdown revealed G1 phase arrest with reduced cell cycle protein expression. Combined TargetScan and reporter assays revealed a direct link between miR-1270 and LINC00094. Ectopic miR-1270 expression inhibited melanoma cell growth and motility while inducing apoptosis. Finally, through in silico analysis, we identified two miR-1270 target genes, CD276 and centromere protein M (CENPM), which may be involved in the biological functions of LINC00094.

CONCLUSIONS

Overall, LINC00094 expression may regulate melanoma cell growth and motility by modulating the expression of miR-1270, and targeting genes of CD276 and CENPM indicating its therapeutic potential in melanoma treatment.

Overexpression of miR-199b-5p in Colony Forming Unit-Hill's Colonies Positively Mediates the Inflammatory Response in Subclinical Cardiovascular Disease Model: Metformin Therapy Attenuates Its Expression

Well-controlled type 1 diabetes (T1DM) is characterized by inflammation and endothelial dysfunction, thus constituting a suitable model of subclinical cardiovascular disease (CVD). miR-199b-5p overexpression in murine CVD has shown proatherosclerotic effects. We hypothesized that miR-199b-5p would be overexpressed in subclinical CVD yet downregulated following metformin therapy. Inflammatory and vascular markers were measured in 29 individuals with T1DM and 20 matched healthy controls (HCs). miR-199b-5p expression in CFU-Hill's colonies was analyzed from each study group, and correlations with inflammatory/vascular health indices were evaluated. Significant upregulation of miR-199b-5p was observed in T1DM, which was significantly downregulated by metformin. miR-199b-5p correlated positively with vascular endothelial growth factor-D and c-reactive protein (CRP: nonsignificant). ROC analysis determined miR-199b-5p to define subclinical CVD by discriminating between HCs and T1DM individuals. ROC analyses of HbA1c and CRP showed that the upregulation of miR-199b-5p in T1DM individuals defined subclinical CVD at HbA1c > 44.25 mmol and CRP > 4.35 × 106 pg/mL. Ingenuity pathway analysis predicted miR-199b-5p to inhibit the target genes SIRT1, ETS1, and JAG1. Metformin was predicted to downregulate miR-199b-5p via NFATC2 and STAT3 and reverse its downstream effects. This study validated the antiangiogenic properties of miR-199b-5p and substantiated miR-199b-5p overexpression as a biomarker of subclinical CVD. The downregulation of miR-199b-5p by metformin confirmed its cardio-protective effect.

Insight into the Role of the miR-584 Family in Human Cancers

Among the non-coding RNAs, the aberrant expression of microRNAs (miRNAs) is well described in the oncology field. It is clear that the altered expression of miRNAs is crucial for a variety of processes such as proliferation, apoptosis, motility, angiogenesis and metastasis insurgence. Considering these aspects, RNA-based therapies and the use of miRNAs as non-invasive biomarkers for early diagnosis are underlined as promising opportunities against cancer death. In the era of precision medicine, significant progress in next-generation sequencing (NGS) techniques has broadened knowledge regarding the miRNAs expression profile in cancer tissues and in the blood of cancer patients. In this scenario, pre-clinical and clinical studies suggested that the members of the miR-584 family, i.e., miR-584-5p and -3p, are prominent players in cancer development and progression. Under some conditions, these miRNAs are under-expressed in cancer tissues acting as tumor suppressors, while in other conditions, they are overexpressed, acting as oncogenes increasing the aggressive behavior of cancer cells. The aim of this review is to provide a comprehensive and up-to-date overview on the expression, upstream genes, molecular targets and signaling pathways influenced by the miR-584 family (i.e., miR-584-3p and -5p) in various human solid and hematological cancers. To achieve this goal, 64 articles on this topic are discussed. Among these articles, 55 are focused on miR-584-5p, and it is outlined how this miRNA could be used in future applications as a potential new therapeutic strategy and diagnostic tool.

Phenformin activates ER stress to promote autophagic cell death via NIBAN1 and DDIT4 in oral squamous cell carcinoma independent of AMPK

The efficient clinical treatment of oral squamous cell carcinoma (OSCC) is still a challenge that demands the development of effective new drugs. Phenformin has been shown to produce more potent anti-tumor activities than metformin on different tumors, however, not much is known about the influence of phenformin on OSCC cells. We found that phenformin suppresses OSCC cell proliferation, and promotes OSCC cell autophagy and apoptosis to significantly inhibit OSCC cell growth both in vivo and in vitro. RNA-seq analysis revealed that autophagy pathways were the main targets of phenformin and identified two new targets DDIT4 (DNA damage inducible transcript 4) and NIBAN1 (niban apoptosis regulator 1). We found that phenformin significantly induces the expression of both DDIT4 and NIBAN1 to promote OSCC autophagy. Further, the enhanced expression of DDIT4 and NIBAN1 elicited by phenformin was not blocked by the knockdown of AMPK but was suppressed by the knockdown of transcription factor ATF4 (activation transcription factor 4), which was induced by phenformin treatment in OSCC cells. Mechanistically, these results revealed that phenformin triggers endoplasmic reticulum (ER) stress to activate PERK (protein kinase R-like ER kinase), which phosphorylates the transitional initial factor eIF2, and the increased phosphorylation of eIF2 leads to the increased translation of ATF4. In summary, we discovered that phenformin induces its new targets DDIT4 and especially NIBAN1 to promote autophagic and apoptotic cell death to suppress OSCC cell growth. Our study supports the potential clinical utility of phenformin for OSCC treatment in the future.

Proteogenomic insights suggest druggable pathways in endometrial carcinoma

We characterized a prospective endometrial carcinoma (EC) cohort containing 138 tumors and 20 enriched normal tissues using 10 different omics platforms. Targeted quantitation of two peptides can predict antigen processing and presentation machinery activity, and may inform patient selection for immunotherapy. Association analysis between MYC activity and metformin treatment in both patients and cell lines suggests a potential role for metformin treatment in non-diabetic patients with elevated MYC activity. PIK3R1 in-frame indels are associated with elevated AKT phosphorylation and increased sensitivity to AKT inhibitors. CTNNB1 hotspot mutations are concentrated near phosphorylation sites mediating pS45-induced degradation of β-catenin, which may render Wnt-FZD antagonists ineffective. Deep learning accurately predicts EC subtypes and mutations from histopathology images, which may be useful for rapid diagnosis. Overall, this study identified molecular and imaging markers that can be further investigated to guide patient stratification for more precise treatment of EC.

Could Metformin and Resveratrol Support Glioblastoma Treatment? A Mechanistic View at the Cellular Level

Glioblastoma, a malignant brain tumor, is a common primary brain tumor in adults, with diabetes mellitus being a crucial risk factor. This review examines how the antidiabetic drug metformin and dietary supplement resveratrol can benefit the treatment of glioblastoma. Metformin and resveratrol have demonstrated action against relevant pathways in cancer cells. Metformin and resveratrol inhibit cell proliferation by downregulating the PI3K/Akt pathway, activating mTOR, and increasing AMPK phosphorylation, resulting in lower proliferation and higher apoptosis levels. Metformin and resveratrol both upregulate and inhibit different cascades in the MAPK pathway. In vivo, the drugs reduced tumor growth and volume. These actions show how metformin and resveratrol can combat cancer with both glucose-dependent and glucose-independent effects. The pre-clinical results, alongside the lack of clinical studies and the rise in novel delivery mechanisms, warrant further clinical investigations into the applications of metformin and resveratrol as both separate and as a combination complement to current glioblastoma therapies.

Repurposing of Chronically Used Drugs in Cancer Therapy: A Chance to Grasp

Despite the advancement in drug discovery for cancer therapy, drug repurposing remains an exceptional opportunistic strategy. This approach offers many advantages (faster, safer, and cheaper drugs) typically needed to overcome increased challenges, i.e., side effects, resistance, and costs associated with cancer therapy. However, not all drug classes suit a patient's condition or long-time use. For that, repurposing chronically used medications is more appealing. This review highlights the importance of repurposing anti-diabetic and anti-hypertensive drugs in the global fight against human malignancies. Extensive searches of all available evidence (up to 30 March 2023) on the anti-cancer activities of anti-diabetic and anti-hypertensive agents are obtained from multiple resources (PubMed, Google Scholar, ClinicalTrials.gov, Drug Bank database, ReDo database, and the National Institutes of Health). Interestingly, more than 92 clinical trials are evaluating the anti-cancer activity of 14 anti-diabetic and anti-hypertensive drugs against more than 15 cancer types. Moreover, some of these agents have reached Phase IV evaluations, suggesting promising official release as anti-cancer medications. This comprehensive review provides current updates on different anti-diabetic and anti-hypertensive classes possessing anti-cancer activities with the available evidence about their mechanism(s) and stage of development and evaluation. Hence, it serves researchers and clinicians interested in anti-cancer drug discovery and cancer management.

SCAMP3 promotes breast cancer progression through the c-MYC-β-Catenin-SQSTM1 growth and stemness axis

The cellular trafficking protein secretory-carrier-membrane-protein 3 (SCAMP3) has been previously shown to promote hepatocellular carcinoma, melanoma, glioma and pancreatic adenocarcinoma. Moreover, previous work has shown that SCAMP3 regulates the epidermal growth factor receptor (EGFR) in triple negative breast cancer (TNBC). However, the oncogenic role of SCAMP3 in different molecular subtypes of breast cancer (BRCA) remains largely unknown. In this study, the role of SCAMP3 in different molecular subtypes of BRCA was investigated using in silico, in vitro and in vivo approaches. In silico analysis of BRCA patient samples showed that SCAMP3 is highly overexpressed in different BRCA molecular subtypes, advanced disease grades and lymph node metastatic stages. Depletion of SCAMP3 inhibited BRCA cell growth, stemness, clonogenic potential and migration and promoted autophagy and cellular senescence. The expression of stemness markers CD44 and OCT4A was reduced in SCAMP3-silenced MDA-MB-231 cells. SCAMP3 overexpression promoted cell proliferation, clonogenicity, tumor spheroid formation and migration in vitro and tumor growth in vivo. SCAMP3 promoted epithelial-mesenchymal-transition (EMT) by regulating E-cadherin expression. SCAMP3 enhanced in vivo tumor growth in MDA-MB-231 tumor xenograft mouse model. Mechanistically, SCAMP3 depletion inhibited β-Catenin, c-MYC and SQSTM1 expression, while its overexpression increased the expression of the same oncogenic proteins. Increased SCAMP3 expression associated with increased chemoresistance in BRCA cells while its depletion associated with increased sensitivity to chemotherapy. BRCA patients with high SCAMP3 expression showed poor prognosis, decreased overall survival and relapse free survival relative to counterparts with reduced SCAMP3 expression. These findings suggest that SCAMP3 exerts a wide range of oncogenic effects in different molecular subtypes of BRCA by modulating the c-MYC-β-Catenin-SQSTM1 axis that targets tumor growth, metastasis, stemness and chemoresistance.

A systematic review of the uses of metformin in dermatology

Metformin is an established staple drug in the management of Type 2 diabetes mellitus. In this systematic review, we sought to establish the clinical utility of metformin in a range of dermatological conditions. The pathophysiology of acne vulgaris and polycystic ovarian syndrome (PCOS) is well suited to the pharmacological profile of metformin, and we found evidence for its efficacy in managing these conditions. We found some evidence for the use of metformin particularly in acne and PCOS; however, the evidence base is of mixed quality. There is scope for clinicians to consider metformin as an adjunct therapy in acne and PCOS. There is generally insufficient evidence to recommend metformin in other dermatological conditions.

A Network of MicroRNAs and mRNAs Involved in Melanosome Maturation and Trafficking Defines the Lower Response of Pigmentable Melanoma Cells to Targeted Therapy

BACKGROUND

The ability to increase their degree of pigmentation is an adaptive response that confers pigmentable melanoma cells higher resistance to BRAF inhibitors (BRAFi) compared to non-pigmentable melanoma cells.

METHODS

Here, we compared the miRNome and the transcriptome profile of pigmentable 501Mel and SK-Mel-5 melanoma cells vs. non-pigmentable A375 melanoma cells, following treatment with the BRAFi vemurafenib (vem). In depth bioinformatic analyses (clusterProfiler, WGCNA and SWIMmeR) allowed us to identify the miRNAs, mRNAs and biological processes (BPs) that specifically characterize the response of pigmentable melanoma cells to the drug. Such BPs were studied using appropriate assays in vitro and in vivo (xenograft in zebrafish embryos).

RESULTS

Upon vem treatment, miR-192-5p, miR-211-5p, miR-374a-5p, miR-486-5p, miR-582-5p, miR-1260a and miR-7977, as well as GPR143, OCA2, RAB27A, RAB32 and TYRP1 mRNAs, are differentially expressed only in pigmentable cells. These miRNAs and mRNAs belong to BPs related to pigmentation, specifically melanosome maturation and trafficking. In fact, an increase in the number of intracellular melanosomes-due to increased maturation and/or trafficking-confers resistance to vem.

CONCLUSION

We demonstrated that the ability of pigmentable cells to increase the number of intracellular melanosomes fully accounts for their higher resistance to vem compared to non-pigmentable cells. In addition, we identified a network of miRNAs and mRNAs that are involved in melanosome maturation and/or trafficking. Finally, we provide the rationale for testing BRAFi in combination with inhibitors of these biological processes, so that pigmentable melanoma cells can be turned into more sensitive non-pigmentable cells.

GBM Cells Exhibit Susceptibility to Metformin Treatment According to TLR4 Pathway Activation and Metabolic and Antioxidant Status

Glioblastoma (GBM) is an aggressive brain cancer associated with poor overall survival. The metabolic status and tumor microenvironment of GBM cells have been targeted to improve therapeutic strategies. TLR4 is an important innate immune receptor capable of recognizing pathogens and danger-associated molecules. We have previously demonstrated the presence of TLR4 in GBM tumors and the decreased viability of the GBM tumor cell line after lipopolysaccharide (LPS) (TLR4 agonist) stimulation. In the present study, metformin (MET) treatment, used in combination with temozolomide (TMZ) in two GBM cell lines (U87MG and A172) and stimulated with LPS was analyzed. MET is a drug widely used for the treatment of diabetes and has been repurposed for cancer treatment owing to its anti-proliferative and anti-inflammatory actions. The aim of the study was to investigate MET and LPS treatment in two GBM cell lines with different metabolic statuses. MET treatment led to mitochondrial respiration blunting and oxidative stress with superoxide production in both cell lines, more markedly in U87MG cells. Decreased cell viability after MET + TMZ and MET + LPS + TMZ treatment was observed in both cell lines. U87MG cells exhibited apoptosis after MET + LPS + TMZ treatment, promoting increased ER stress, unfolded protein response, and BLC2 downregulation. LPS stimulation of U87MG cells led to upregulation of SOD2 and genes related to the TLR4 signaling pathway, including IL1B and CXCL8. A172 cells attained upregulated antioxidant gene expression, particularly SOD1, TXN and PRDX1-5, while MET treatment led to cell-cycle arrest. In silico analysis of the TCGA-GBM-RNASeq dataset indicated that the glycolytic plurimetabolic (GPM)-GBM subtype had a transcriptomic profile which overlapped with U87MG cells, suggesting GBM cases exhibiting this metabolic background with an activated inflammatory TLR4 pathway may respond to MET treatment. For cases with upregulated CXCL8, coding for IL8 (a pro-angiogenic factor), combination treatment with an IL8 inhibitor may improve tumor growth control. The A172 cell line corresponded to the mitochondrial (MTC)-GBM subtype, where MET plus an antioxidant inhibitor, such as anti-SOD1, may be indicated as a combinatory therapy.

Metformin Induces Apoptosis in Human Pancreatic Cancer (PC) Cells Accompanied by Changes in the Levels of Histone Acetyltransferases (Particularly, p300/CBP-Associated Factor (PCAF) Protein Levels)

Accumulating evidence (mainly from experimental research) suggests that metformin possesses anticancer properties through the induction of apoptosis and inhibition of the growth and proliferation of cancer cells. However, its effect on the enzymes responsible for histone acetylation status, which plays a key role in carcinogenesis, remains unclear. Therefore, the aim of our study was to evaluate the impact of metformin on histone acetyltransferases (HATs) (i.e., p300/CBP-associated factor (PCAF), p300, and CBP) and on histone deacetylases (HDACs) (i.e., SIRT-1 in human pancreatic cancer (PC) cell lines, 1.2B4, and PANC-1). The cells were exposed to metformin, an HAT inhibitor (HATi), or a combination of an HATi with metformin for 24, 48, or 72 h. Cell viability was determined using an MTT assay, and the percentage of early apoptotic cells was determined with an Annexin V-Cy3 Apoptosis Detection Assay Kit. Caspase-9 activity was also assessed. SIRT-1, PCAF, p300, and CBP expression were determined at the mRNA and protein levels using RT-PCR and Western blotting methods, respectively. Our results reveal an increase in caspase-9 in response to the metformin, indicating that it induced the apoptotic death of both 1.2B4 and PANC-1 cells. The number of cells in early apoptosis and the activity of caspase-9 decreased when treated with an HATi alone or a combination of an HATi with metformin, as compared to metformin alone. Moreover, metformin, an HATi, and a combination of an HATi with metformin also modified the mRNA expression of SIRT-1, PCAF, CBP, and p300. However, metformin did not change the expression of the studied genes in 1.2B4 cells. The results of the Western blot analysis showed that metformin diminished the protein expression of PCAF in both the 1.2B4 and PANC-1 cells. Hence, it appears possible that PCAF may be involved in the metformin-mediated apoptosis of PC cells.

Pharmacotherapy of type 2 diabetes: An update and future directions

Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.

Six MicroRNA Prognostic Models for Overall Survival of Lung Adenocarcinoma

Objective

The purpose of this study is to screen for microRNAs (miRNAs) associated with the prognosis of lung adenocarcinoma (LUAD) and to explore its prognosis and effects on the tumor microenvironment in patients with LUAD.

Methods

Gene expression data, miRNA expression data, and clinical data for two different databases, TCGA-LUAD and CPTAC-3 LUAD, were downloaded from the GDC database. The miRNA prognosis of LUAD was filtered by the Cox proportional hazard model and the Least Absolute Shrinkage and Selection Operator (LASSO) regression model. The performance of the model was validated by time-dependent receiver operating characteristics (ROC) curves. Possible biological processes associated with the miRNAs target gene were analyzed through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Finally, the prognostic model was scored by risk, divided into high- and low-risk groups by median, and the differences in the immersion level of 21 immune cells in the high- and low-risk groups were assessed. To gain a deeper understanding of the underlying mechanism behind the model, the two most important miRNAs in the model, miR-195-3p and miR-5571-5p, were selected for HPA database validation and ceRNA network construction.

Results

Of the 209 variance expressions identified in the screening analysis, 145 were upregulated and 64 were downregulated by miRNAs. The prognostic models of six miRNA genes were obtained: miR-195-3p, miR-5571-5p, miR-584-3p, miR-494-3p, miR-4664-3p, and miR-1293. These six genes were significantly associated with survival rates in LUAD patients. In particular, miR-1293, miR-195-3p, and miR-5571-5p are highly correlated with OS. The higher expression of miR-195-3p and miR-5571-5p, the better survival of LUAD OS is, and these two miRNA expressions contribute the most to the model. Finally, after sorting the risk scores calculated from low to high using the prognostic model, the patients with higher scores had shorter survival time and higher frequency of death, and there were significant differences in the immersion levels of 21 immune cells in the high- and low-risk groups. ceRNA network analysis found that TM9SF3 was regulated by miR-195-3p and was highly expressed in the tissues of LUAD patients, and the prognosis of the patients was poor.

Conclusions

miR-195-3p, miR-5571-5p, miR-584-3p, miR-494-3p, miR-4664-3p, and miR-1293 may be used as new biomarkers for prognosis prediction of LUAD. Our results also identified a lncRNA MEG3/miR-195-3p/RAB1A/TM9SF3 regulatory axis, which may also play an important role in the progression of LUAD. Further study needs to be conducted to verify this result.

Metformin inhibits melanoma cell metastasis by suppressing the miR-5100/SPINK5/STAT3 axis

Melanoma is the most lethal skin cancer characterized by its high metastatic potential. It is urgent to find novel therapy strategies to overcome this feature. Metformin has been confirmed to suppress invasion and migration of various types of cancer. However, additional mechanisms underlying the antimetastatic effect of metformin on melanoma require further investigation. Here, we performed microarray analysis and uncovered an altered mRNA and miRNA expression profile between melanoma and nevus. Luciferase reporter assay confirmed that miR-5100 targets SPINK5 to activate STAT3 phosphorylation. Migration and wound healing assays showed that the miR-5100/SPINK5/STAT3 axis promotes melanoma cell metastasis; the mechanism was proven by initiation of epithelial–mesenchymal transition. Co-immunoprecipitation (Co-IP) further confirmed an indirect interaction between SPINK5 and STAT3. Furthermore, metformin dramatically inhibited miR-5100/SPINK5/STAT3 pathway, and decreased B16-F10 cell metastasis to lung in C57 mouse module. Intriguingly, pretreatment of metformin before melanoma cell injection improved this effect further. These findings exposed the underlying mechanisms of action of metformin and update the use of this drug to prevent metastasis in melanoma.

Downstream Regulatory Network of MYBL2 Mediating Its Oncogenic Role in Melanoma

The transcription factor MYBL2 is widely expressed in proliferating cells. Aberrant expression of MYBL2 contributes to tumor malignancy and is associated with poor patient prognosis. However, the downstream transcriptional network that mediates its oncogenic properties remains elusive. In the present study, we observed that MYBL2 was overexpressed in malignant and metastatic melanoma patient samples and that the high expression level of MYBL2 was significantly associated with poor prognosis. A loss-of-function study demonstrated that MYBL2 depletion significantly decreased cell proliferation and migration and prevented cell cycle progression. We also determined that MYBL2 promoted the formation of melanoma stem-like cell populations, indicating its potential as a therapeutic target for treating resistant melanoma. Mechanistically, we constructed an MYBL2 regulatory network in melanoma by integrating RNA-seq and ChIP-seq data. EPPK1, PDE3A, and FCGR2A were identified as three core target genes of MYBL2. Importantly, multivariate Cox regression and survival curve analysis revealed that PDE3A and EPPK1 were negatively correlated with melanoma patient survival; however, FCGR2A was positively correlated with patient survival. Overall, our findings elucidate an MYBL2 regulatory network related to cell proliferation and cancer development in melanoma, suggesting that MYBL2 may be potentially targeted for melanoma diagnosis and treatment.

SCAMP3 Regulates EGFR and Promotes Proliferation and Migration of Triple-Negative Breast Cancer Cells through the Modulation of AKT, ERK, and STAT3 Signaling Pathways

Triple-negative breast cancer (TNBC) is the most aggressive, metastatic, and lethal breast cancer subtype. To improve the survival of TNBC patients, it is essential to explore new signaling pathways for the further development of effective drugs. This study aims to investigate the role of the secretory carrier membrane protein 3 (SCAMP3) in TNBC and its association with the epidermal growth factor receptor (EGFR). Through an internalization assay, we demonstrated that SCAMP3 colocalizes and redistributes EGFR from the cytoplasm to the perinucleus. Furthermore, SCAMP3 knockout decreased proliferation, colony and tumorsphere formation, cell migration, and invasion of TNBC cells. Immunoblots and degradation assays showed that SCAMP3 regulates EGFR through its degradation. In addition, SCAMP3 modulates AKT, ERK, and STAT3 signaling pathways. TNBC xenograft models showed that SCAMP3 depletion delayed tumor cell proliferation at the beginning of tumor development and modulated the expression of genes from the PDGF pathway. Additionally, analysis of TCGA data revealed elevated SCAMP3 expression in breast cancer tumors. Finally, patients with TNBC with high expression of SCAMP3 showed decreased RFS and DMFS. Our findings indicate that SCAMP3 could contribute to TNBC development through the regulation of multiple pathways and has the potential to be a target for breast cancer therapy.

Development and evaluation of core-shell nanocarrier system for enhancing the cytotoxicity of doxorubicin/ metformin combination against breast cancer cell line

Breast cancer is the most invasive and life-threatening cancer in women. The treatment options are usually a combination of mastectomy, radiation therapy, hormonal therapy and chemotherapy. As a standard practice, doxorubicin (DOX) is one of the commonly used drugs for breast cancer treatment. However, DOX is known to have many harmful adverse effects including its cardiotoxicity. Hence, recent reports used metformin (MET), an anti-diabetic drug, as an adjuvant therapy to decrease the severity of DOX's adverse effects and to improve its ultimate therapeutic outcome. The current study is aimed at co-loading and enhancing the encapsulation efficiency of the hydrophilic DOX and MET in poly(lactic-co-glycolic acid) (PLGA) nanocapsules (NCs) with oil core for breast cancer treatment. The NCs were developed by single emulsification-solvent diffusion technique, and were optimized through using two types of oils, pluronics and PLGA (50:50) of different molecular weights followed by various physicochemical characterizations. The obtained DOX/MET-loaded NCs showed the size and polydispersity index (PDI) of 203.0 ± 3.4 nm and 0.081 ± 0.03, respectively with a surface charge of -2.15 ± 0.2 mV. The entrapment efficiency of DOX and MET were about 93.7% ± 2.9 and 70% ± 1.6, respectively. The developed PLGA core-shell NCs successfully sustained the DOX/MET release for more than 30 days. The in-vitro results showed a significant enhancement in DOX cytotoxic effect as well as a duplication in its apoptotic effect upon addition of MET for both free DOX/MET combination and DOX/MET-loaded PLGA NCs against MCF-7. Besides, flow cytometry demonstrated that the DOX/MET-loaded NCs possess their antitumor effect by preventing DNA replication and cell division. This study provides a promising facile, rapid and reproducible single emulsification-solvent diffusion technique for improving the encapsulation and release of hydrophilic drugs in nanocapsules for biomedical applications.

Downregulated long intergenic non-coding RNA 00,174 represses malignant biological behaviors of lung cancer cells by regulating microRNA-584-3p/ribosomal protein S24 axis

The detailed regulatory mechanism of LINC00174 in lung cancer (LC) development remains largely unknown. This research was designed to probe into the impacts of LINC00174 in LC cells through modulating the microRNA (miR)-584-3p/ribosomal protein S24 (RPS24) axis. LINC00174, miR-584-3p, and RPS24 expression levels in LC cells and tissues were examined. The constructs altering LINC00174, miR-584-3p, or RPS24 expression were transfected into LC cells to examine the malignant phenotypes of LC cells. The relations among LINC00174, miR-584-3p, and RPS24 were validated. LINC00174 and RPS24 were high-expressed while miR-584-3p was low-expressed in LC. Downregulated LINC00174 or RPS24 or upregulated miR-584-3p inhibited the malignant biological behaviors of LC cells. The silenced miR-584-3p could reverse the repressive effects of reduced LINC00174 on the development of LC cells; while RPS24 overexpression inverted the repressive effects of miR-584-3p elevation on LC cells. Mechanically, LINC00174 bound to miR-584-3p that targeted RPS24. Repressed LINC00174 can relieve the malignant phenotypes of LC cells via modulating the miR-584-3p/RPS24 axis.

Long Noncoding RNA LOC550643 Acts as an Oncogene in the Growth Regulation of Colorectal Cancer Cells

Long noncoding RNAs play a key role in the progression of colorectal cancer (CRC). However, the role and mechanism of LOC550643 in CRC cell growth and metastasis remain largely unknown. In this study, we assessed the clinical impacts of LOC550643 on CRC through the analysis of The Cancer Genome Atlas database, which revealed the significant upregulation of LOC550643 in CRC. Moreover, the high expression of LOC550643 was associated with poor survival in patients with CRC (p = 0.001). Multivariate Cox regression analysis indicated that LOC550643 overexpression was an independent prognostic factor for shorter overall survival in patients with CRC (adjusted hazard ratio, 1.90; 95% confidence interval, 1.21-3.00; p = 0.006). A biological function analysis revealed that LOC550643 knockdown reduced colon cancer cell growth by hindering cell cycle progression. In addition, LOC550643 knockdown significantly induced cell apoptosis through the inhibition of signaling activity in phosphoinositide 3-kinases. Moreover, LOC550643 knockdown contributed to the inhibition of migration and invasion ability in colon cancer cells. Furthermore, miR-29b-2-5p interacted with the LOC550643 sequence. Ectopic miR-29b-2-5p significantly suppressed colon cancer cell growth and motility and induced cell apoptosis. Our findings suggest that, LOC550643-miR-29b-2-5p axis was determined to participate in the growth and metastasis of colon cancer cells; this could serve as a useful molecular biomarker for cancer diagnosis and as a potential therapeutic target for CRC.

Metformin inhibits gastric cancer cell proliferation by regulation of a novel Loc100506691-CHAC1 axis

Long noncoding RNAs (lncRNAs) are a group of nonprotein coding transcripts that play a critical role in cancer progression. However, the role of lncRNA in metformin-induced inhibition of cell growth and its biological function in gastric cancer remain largely unknown. In this study, we identified an oncogenic lncRNA, Loc100506691, the expression of which was decreased in gastric cancer cells with metformin treatment. Moreover, Loc100506691 was significantly overexpressed in gastric cancer compared with adjacent normal tissues (p < 0.001), and high Loc100506691 expression was significantly correlated with poor survival of patients with gastric cancer. Additionally, Loc100506691 knockdown could significantly suppress gastric cancer cell growth in vitro, and ectopic Loc100506691 expression accelerated tumor growth in an in vivo mouse model. Analysis of the cell cycle revealed that Loc100506691 knockdown induced cell cycle arrest at the G2/M phase by impairing cell entry from the G2/M to G1 phase. Loc100506691 negatively regulated CHAC1 expression by modulating miR-26a-5p/miR-330-5p expression, and CHAC1 knockdown markedly attenuated Loc100506691 knockdown-induced gastric cancer cell growth and motility suppression. We concluded that anti-proliferative effects of metformin in gastric cancer may be partially caused by suppression of the Loc100506691-miR-26a-5p/miR-330-5p-CHAC1 axis.

Cancer and diabetes: the interlinking metabolic pathways and repurposing actions of antidiabetic drugs

Cancers are regarded as one of the main causes of death and result in high health burden worldwide. The management of cancer include chemotherapy, surgery and radiotherapy. The chemotherapy, which involves the use of chemical agents with cytotoxic actions is utilised as a single treatment or combined treatment. However, these managements of cancer such as chemotherapy poses some setbacks such as cytotoxicity on normal cells and the problem of anticancer drug resistance. Therefore, the use of other therapeutic agents such as antidiabetic drugs is one of the alternative interventions used in addressing some of the limitations in the use of anticancer agents. Antidiabetic drugs such as sulfonylureas, biguanides and thiazolidinediones showed beneficial and repurposing actions in the management of cancer, thus, the activities of these drugs against cancer is attributed to some of the metabolic links between the two disorders and these includes hyperglycaemia, hyperinsulinemia, inflammation, and oxidative stress as well as obesity. Furthermore, some studies showed that the use of antidiabetic drugs could serve as risk factors for the development of cancerous cells particularly pancreatic cancer. However, the beneficial role of these chemical agents overweighs their detrimental actions in cancer management. Hence, the present review indicates the metabolic links between cancer and diabetes and the mechanistic actions of antidiabetic drugs in the management of cancers.

Metformin pretreatment reduces effect to dacarbazine and suppresses melanoma cell resistance

Oxidative stress role on metformin process of dacarbazine (DTIC) inducing resistance of B16F10 melanoma murine cells are investigated. To induce resistance to DTIC, murine melanoma cells were exposed to increasing concentrations of dacarabazine (DTIC-res group). Metformin was administered before and during the induction of resistance to DTIC (MET-DTIC). The oxidative stress parameters of the DTIC-res group showed increased levels of malondialdehyde (MDA), thiol, and reduced nuclear p53, 8-hydroxy-2'-deoxyguanosine (8-OH-DG), nuclear factor kappa B (NF-ĸB), and Nrf2. In presence of metformin in the resistant induction process to DTIC, (MET-DTIC) cells had increased antioxidant thiols, MDA, nuclear p53, 8-OH-DG, Nrf2, and reducing NF-ĸB, weakening the DTIC-resistant phenotype. The exclusive administration of metformin (MET group) also induced the cellular resistance to DTIC. The MET group presented high levels of total thiols, MDA, and reduced percentage of nuclear p53. It also presented reduced nuclear 8-OH-DG, NF-ĸB, and Nrf2 when compared with the control. Oxidative stress and the studied biomarkers seem to be part of the alterations evidenced in DTIC-resistant B16F10 cells. In addition, metformin administration is able to play a dual role according to the experimental protocol, preventing or inducing a DTIC-resistant phenotype. These findings should help future research with the aim of investigating DTIC resistance in melanoma.

Biguanides drugs: Past success stories and promising future for drug discovery

Biguanides have attracted much attention a century ago and showed resurgent interest in recent years after a long period of dormancy. They constitute an important class of therapeutic agents suitable for the treatment of a wide spectrum of diseases. Therapeutic indications of biguanides include antidiabetic, antimalarial, antiviral, antiplaque, and bactericidal applications. This review presents an extensive overview of the biological activity of biguanides and different mechanisms of action of currently marketed biguanide-containing drugs, as well as their pharmacological properties when applicable. We highlight the recent developments in research on biguanide compounds, with a primary focus on studies on metformin in the field of oncology. We aim to provide a critical overview of all main bioactive biguanide compounds and discuss future perspectives for the design of new drugs based on the biguanide fragment.

Antitumor Effect of Metformin in Combination with Binimetinib on Melanoma Cells

Cutaneous melanoma is a fatal disease for patients with distant metastasis. Metformin is the most widely used anti-diabetic drug, and proved to suppress cell proliferation and metastasis in diverse cancers including melanoma. We previously reported that MEK inhibitor trametinib increases the expression of epithelial-mesenchymal transition (EMT) regulators and melanoma cell motility, which are suppressed by addition of metformin in A375 melanoma cells. To confirm our findings further, we first evaluated the effect of metformin in combination with another MEK inhibitor binimetinib on cell viability in G361 melanoma cells. We then investigated whether binimetinib affects the expression of EMT regulators and cell motility. We finally monitored the effect of metformin on binimetinib-induced cell migration. Cell viability assay showed that combination index (CI) value at ED₅₀ is 0.80, suggesting synergy for the combination of metformin with binimetinib. Our results also revealed that binimetinib increased the expression of EMT regulators such as integrin αV, fibronectin and slug, which correlate well with the enhanced cell migration in wound healing assay. Metformin, on the contrary, suppressed the expression of sparc, integrin αV, fibronectin and N-cadherin with the reduced cell motility. The combination treatment showed that metformin counteracts the binimetinib-induced increase of cell motility. Overall, these results suggest that metformin with binimetinib might be useful as a potential therapeutic adjuvant against cell survival and metastatic activity in melanoma patients.

How metformin affects various malignancies by means of microRNAs: a brief review

Metformin known as the first-line orally prescribed drug for lowering blood glucose in type II diabetes (T2DM) has recently found various therapeutic applications including in cancer. Metformin has been studied for its influences in prevention and treatment of cancer through multiple mechanisms such as microRNA (miR) regulation. Alteration in the expression of miRs by metformin may play an important role in the treatment of various cancers. MiRs are single-stranded RNAs that are involved in gene regulation. By binding to the 3'UTR of target mRNAs, miRs influence protein levels. Irregularities in the expression of miRs that control the expression of oncogenes and tumor suppressor genes are associated with the onset and progression of cancer. Metformin may possess an effect on tumor prevention and progression by modifying miR expression and downstream pathways. Here, we summarize the effect of metformin on different types of cancer by regulating the expression of various miRs and the associated downstream molecules.

Peripheral BDNF correlated with miRNA in BD-II patients

OBJECTIVES

We have identified the association between peripheral levels of candidate miRNAs (miR-7-5p, miR-142-3p, miR-221-5p, and miR-370-3p) for BD-II in previous study. Most of these miRNAs are associated with regulation of expression of peripheral brain derived neurotrophic factor (BDNF) levels. In order to clarify the underlying mechanism of BDNF and miRNAs in the pathogenesis of BD-II, it is of interest to investigate the relation between the peripheral levels of miR-7-5p, miR-142-3p, miR-221-5p, miR-370-3p with BDNF levels. Because the BDNF Val66Met polymorphism influence the secretion of BDNF, we further stratified the above correlations by this polymorphism.

METHODS

We have recruited 98 BD-II patients. Beside analyzing peripheral levels of miR-7-5p, miR-142-3p, miR-221-5p, miR-370-3p, and BDNF, the genetic distribution of the BDNF Val66Met polymorphism was also analyzed.

RESULTS

We found that the miR7-5p, miR221-5p, and miR370-3p significantly correlated with the BDNF levels for all patients. If stratified by the BDNF Val66Met polymorphism, the significant correlation between miR221-5p and miR370-3p with BDNF only remained in the Val/Met genotype. However, the correlation between miR7-5p and BDNF level is significant in all 3 genotypes.

CONCLUSION

Our result supported that these miRNAs may be involved in the pathomechanism of BD-II through relation with BDNF.

Changes in protein expression due to metformin treatment and hyperinsulinemia in a human endometrial cancer cell line

The incidence of endometrial cancer (EC) has increased over the past years and mainly affects women above the age of 45 years. Metabolic diseases such as obesity and type II diabetes mellitus as well as associated conditions like polycystic ovary syndrome (PCOS), insulin resistance and hyperinsulinemia lead to elevated levels of circulating estrogens. Increased estrogen concentrations, in turn, further trigger the proliferation of endometrial cells and thus promote EC development and progression, especially in the absence of progesterone as seen in postmenopausal women. Elevated blood glucose levels in diabetic patients further contribute to the risk of EC development. Metformin is an insulin-sensitizing biguanide drug, commonly used in the treatment of type II diabetes mellitus, especially in obese patients. Besides its effects on glucose metabolism, metformin displayed anti-cancer effects in various cancer types, including EC. Direct anti-cancer effects of metformin target signaling pathways that are involved in cellular growth and proliferation, e.g. the AKT/PKB/mTOR pathway. Further proteins and pathways have been suggested as potential targets, but the underlying mechanism of action of metformin's anti-cancer activity is still not completely understood. In the present study, the effects of metformin on protein expression were investigated in the human EC cell line HEC-1A using an affinity proteomic approach. Cells were treated with 0.5 mmol/L metformin over a period of 7 days and changes in the expression pattern of 1,300 different proteins were compared to the expression in untreated control cells as well as insulin-treated cells. Insulin treatment (100 ng/mL) was incorporated into the study in order to implement a model for insulin resistance and associated hyperinsulinemia, conditions that are often observed in obese and diabetic patients. Furthermore, the culture medium was supplemented with 10 nmol/L ß-estradiol (E2) during treatments to mimic increased estrogen levels, a common risk factor for EC development. Based on the most prominent and significant changes in expression, a set of 80 proteins was selected and subjected to a more detailed analysis. The data revealed that metformin and insulin targeted similar pathways in the present study and mostly acted on proteins related to proliferation, migration and tumor immune response. These pathways may be affected in a tumor-promoting as well as a tumor-suppressing way by either metformin treatment or insulin supplementation. The consequences for the cells resulting from the detected expression changes were discussed in detail for several proteins. The presented data helps identify potential targets affected by metformin treatment in EC and allows for a better understanding of the mechanism of action of the biguanide drug's anti-cancer activity. However, further investigations are necessary to confirm the observations and conclusions drawn from the presented data after metformin administration, especially for proteins that were regulated in a favorable way, i.e. AKT3, CCND2, CD63, CD81, GFAP, IL5, IL17A, IRF4, PI3, and VTCN1. Further proteins might be of interest, where metformin counteracted unfavorable effects that have been induced by hyperinsulinemia.

Metformin turns 62 in pharmacotherapy: Emergence of non-glycaemic effects and potential novel therapeutic applications

Metformin is the most commonly prescribed oral antidiabetic medication. Direct/indirect activation of Adenosine Monophosphate-activated protein kinase (AMPK) and non-AMPK pathways, amongst others, are deemed to explain the molecular mechanisms of action of metformin. Metformin is an established insulin receptor sensitising antihyperglycemic agent, is highly affordable, and has superior safety and efficacy profiles. Emerging experimental and clinical evidence suggests that metformin has pleiotropic non-glycemic effects. Metformin appears to have weight stabilising, renoprotective, neuroprotective, cardio-vascular protective, and antineoplastic effects and mitigates polycystic ovarian syndrome. Anti-inflammatory and antioxidant effects of metformin seem to qualify it as an adjunct therapy in treating infectious diseases such as tuberculosis, viral hepatitis, and the current novel Covid-19 infections. So far, metformin is the only prescription medicine relevant to the emerging field of senotherapeutics. Non-glycemic effects of metformin favourable to its repurposing in therapeutic use are hereby discussed.

Expression and prognostic analyses of SCAMPs in pancreatic adenocarcinoma

Due to the difficulties in early diagnosis of pancreatic adenocarcinoma (PAAD), many patients fail to receive optimal therapeutic regimens. The Secretory-Carrier-Membrane-Proteins (SCAMPs) are known to be dysregulated in a range of human diseases due to their characterized roles in mammalian cell exocytosis inferred from their functions as integral membrane proteins. However, the expression and prognostic value of SCAMPs in PAAD is poorly characterized. We compared cancer vs. healthy tissue and found that the expression of SCAMPs1-4 was upregulated in PAAD compared to normal tissue. In contrast, SCAMP5 expression was downregulated in PAAD. Moreover, the expression of SCAMPs1-4 was enhanced in PAAD cell lines according to Cancer Cell Line public database. Furthermore, the HPA, GEPIA databases and immunohistochemical analysis from 238 patients suggested that the loss of SCAMP1 led to improved overall survival (OS), whilst lower SCAMP5 levels led to a poorer OS. The univariate and multivariate analysis showed that SCAMP1 and SCAMP5 expression were independent prognostic factors of PAAD. In addition, the cBioPortal for Cancer Genomics, LinkedOmics datasets, and the GEPIA were used to identify the co-expression genes of SCAMP1,5 and the correlation between SCAMPs members. We conclude that SCAMPs 1 and 5 significantly represent promising diagnosis and prognostic biomarkers.

Repurposing of Drug Candidates for Treatment of Skin Cancer

Skin cancers are highly prevalent malignancies that affect millions of people worldwide. These include melanomas and nonmelanoma skin cancers. Melanomas are among the most dangerous cancers, while nonmelanoma skin cancers generally exhibit a more benign clinical pattern; however, they may sometimes be aggressive and metastatic. Melanomas typically appear in body regions exposed to the sun, although they may also appear in areas that do not usually get sun exposure. Thus, their development is multifactorial, comprising endogenous and exogenous risk factors. The management of skin cancer depends on the type; it is usually based on surgery, chemotherapy, immunotherapy, and targeted therapy. In this respect, oncological treatments have demonstrated some progress in the last years; however, current therapies still present various disadvantages such as little cell specificity, recurrent relapses, high toxicity, and increased costs. Furthermore, the pursuit of novel medications is expensive, and the authorization for their clinical utilization may take 10-15 years. Thus, repositioning of drugs previously approved and utilized for other diseases has emerged as an excellent alternative. In this mini-review, we aimed to provide an updated overview of drugs' repurposing to treat skin cancer and discuss future perspectives.

Metformin Antagonizes Ovarian Cancer Cells Malignancy Through MSLN Mediated IL-6/STAT3 Signaling

BACKGROUND

Ovarian cancer is the most lethal gynecological malignancy, and chemotherapy remains the cornerstone for ovarian cancer management. Due to the unsatisfactory prognosis, a better understanding of the underlying molecular carcinogenesis is urgently required.

METHODS

Assays for determining cell growth, cell motility, and apoptosis were employed to evaluate the potential antitumor effects of metformin against ovarian cancer cells. Molecular biological methods were employed to explore the underlying mechanism. Human ovarian cancer samples and Gene Expression Profiling Interactive Analysis (GEPIA) dataset were used for uncovering the clinical significances of mesothelin (MSLN) on ovarian cancer.

RESULTS

In the present work, we found that metformin treatment led to cell growth and cell migration inhibition, and induced cell apoptosis. Metformin administration also impaired cancer cell stemness and the capillary-like structure formation capacity of SKOV3 cells. On mechanism, metformin treatment remarkably reduced mesothelin (MSLN) expression, downregulated IL-6/STAT3 signaling activity, subsequently resulted in VEGF and TGFβ1 expression. We also observed an oncogenic function of MSLN on ovarian cancer.

CONCLUSIONS

Collectively, our findings suggested that metformin exerts anticancer effects by suppressing ovarian cancer cell malignancy, which attributed to MSLN inhibition mediated IL6/STAT3 signaling and VEGF and TGFβ1 downregulation.

SCAMP3 is regulated by miR-128-3p and promotes the metastasis of hepatocellular carcinoma cells through EGFR-MAPK p38 signaling pathway

PURPOSE

To explore the regulatory mechanism of secretory carrier membrane protein 3 (SCAMP3) and miR-128-3p in hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Cancer tissues and adjacent tissues of 52 HCC patients treated in our hospital were collected to explore the prognostic factors affecting their 3-year survival. HCC cells were purchased, the gene expression of Huh-7 and MHCC97 were adjusted by transfection, and the levels of SCAMP3, miR-128-3p, EGFR, p-EGFR, MAPK p38, p-MAPK p38, N-cadherin, vimentin, E-cadherin, cell proliferation, migration, invasion, apoptosis and epithelial-mesenchymal transition (EMT) were detected. A nude mouse model of HCC was constructed to verify the effects of transfection of mimics.

RESULTS

SCAMP3 was elevated in HCC patients and cancer tissues of HCC patients, while miR-128-3p showed opposite effects. High level SCAMP3 and low level miR-128-3p were related to poor prognosis of HCC. Both of them were correlated with excessive drinking history, N-stage, M-stage and pathological differentiation degree of HCC patients, as well as prognostic factors of HCC patients. SCAMP3 up-regulation or miR-128-3p down-regulation could promote HCC cell proliferation, migration, invasion, and transcription and protein levels of EGFR, p-EGFR, MAPK p38, p-MAPK p38, N-cadherin and vimentin, and inhibit HCC cell apoptosis and transcription and protein levels of E-cadherin. Dual luciferase reporter identified the targeting relationship between SCAMP3 and miR-128-3p. When both SCAMP3 and miR-128-3p were elevated or reduced, the biological manifestation of cells was not different from that of miR-NC transfected with unrelated sequences. Besides, miR-128-3p inhibited tumor growth in the HCC model in nude mice.

CONCLUSION

SCAMP3 can be controlled by miR-128-3p and can mediate the EGFR-MAPK p38 signaling pathway to inhibit HCC cell metastasis, which is expected to become a promising therapeutic target for HCC.

Metformin induces apoptosis and inhibits migration by activating the AMPK/p53 axis and suppressing PI3K/AKT signaling in human cervical cancer cells

Human cervical cancer is the fourth most common malignancy among women worldwide, and it is expected to result in 460,000 deaths per year by 2040. Moreover, patients with cervical cancer often display drug resistance and severe side effects; therefore, the development of effective novel chemotherapeutic agents is important. In the present study, the effects of metformin, a first-line therapeutic drug for type 2 diabetes mellitus, were evaluated in cervical cancer. Compared with the control group, metformin significantly inhibited cell viability and migration, and induced apoptosis and cell cycle arrest in human cervical cancer cell lines (CaSki and HeLa). Following metformin treatment, the protein expression levels of p-AMP-activated protein kinase (p-AMPK), which promotes cell death, and the tumor suppressor protein p-p53 were remarkably upregulated in CaSki and C33A cells compared with the control group. Furthermore, compared with the control group, metformin significantly suppressed the PI3K/AKT signaling pathway in CaSki, C33A and HeLa cells. Compound C (an AMPK inhibitor) significantly reversed the effects of metformin on CaSki, C33A and HeLa cell viability, and AMPK and p53 phosphorylation. The results of the present study suggested that metformin induced AMPK-mediated apoptosis, thus metformin may serve as a chemotherapeutic agent for human cervical cancer.

A new aspect of an old friend: the beneficial effect of metformin on anti-tumor immunity

T-cell-based cancer immunotherapies, such as immune checkpoint blockers (ICBs) and chimeric antigen receptor (CAR)-T-cells, have significant anti-tumor effects against certain types of cancer, providing a new paradigm for cancer treatment. However, the activity of tumor infiltrating T-cells (TILs) can be effectively neutralized in the tumor microenvironment (TME) of most solid tumors, rich in various immunosuppressive factors and cells. Therefore, to improve the clinical outcomes of established T-cell-based immunotherapy, adjuvants that can comprehensively relieve multiple immunosuppressive mechanisms of TME are needed. In this regard, recent studies have revealed that metformin has several beneficial effects on anti-tumor immunity. In this mini-review, we understand the immunosuppressive properties of TME and how metformin comprehensively enhances anti-tumor immunity. Finally, we will discuss this old friend’s potential as an adjuvant for cancer immunotherapy.

The impact of metformin on survival in patients with melanoma-national cohort study

PURPOSE

The primary study outcome was melanoma-specific mortality in patients with type 2 diabetes mellitus (T2DM) using metformin.

METHODS

Data regarding patients were provided by the Lithuanian Cancer Registry and were linked with National Health Insurance Fund in accordance with unique personal identification numbers during the period of thirteen years.

RESULTS

About 2817 patients met eligibility criteria and were included in the retrospective cohort study. About 163 patients had pre-existing T2DM and 103 of them were treated with metformin. In the multivariable analysis, there was significant risk difference in melanoma-specific survival between diabetic, metformin-using patients, and nondiabetic patients (P=0.02) in favor of metformin users.

CONCLUSION

Melanoma patients with T2DM treated with metformin had lower risk of melanoma-specific mortality; however, prospective controlled studies are mandatory to confirm this finding.

Therapeutic inhibition of microRNA-21 (miR-21) using locked-nucleic acid (LNA)-anti-miR and its effects on the biological behaviors of melanoma cancer cells in preclinical studies

BACKGROUND

Melanoma is a cancer that has a high mortality rate in the absence of targeted therapy. Conventional therapies such as surgery, chemotherapy, and radiotherapy are associated with poor prognosis. The expression of miR-21 appears to be of clinical importance, and the regulation of its expression appears to be an opportunity for treatment.

METHODS

In this current study, we aimed to evaluate the effects of miR-21 inhibition in- vitro and in-vivo. In-vitro studies have investigated LNA-anti-miR-21 in mouse melanoma cells (B16F10), and in-vivo studies have proposed a model of melanoma in male C57BL/6 mice. To evaluate the anticancer effects of LNA-anti-miR-21, a QRT-PCR analysis was performed using the 2-ΔΔCT method to determine the degree of inhibition of oncomiR-21. The MTT test, propidium iodide/AnnexinV in-vitro, and tumor volume measurement using the QRT-PCR test with the 2-ΔΔCT method were used to estimate the inhibition of miR-21 and the expression of downstream genes including: SNAI1, Nestin (Nes), Oct-4, and NF-kB following miR-21 inhibition. Finally, immunohistochemistry was conducted for an in-vivo animal study.

RESULTS

MiR-21 expression was inhibited by 80% after 24 h of B16F10 cell line transfection with LNA-anti-miR-21. The MTT test showed a significant reduction in the number of transfected cells with LNA-anti-miR-21. The transfected cells showed a significant increase in apoptosis in comparison with the control and scrambled LNA groups. According to our in vivo findings, anti-miR-21 could reduce tumor growth and volume in mice receiving intraperitoneal anti-miR after 9 days. The expression of the SNAI1gene was significantly reduced compared to the controls. Immunohistochemical analysis showed no change in CD133 and NF-kB markers.

CONCLUSION

Our findings suggest LNA-anti-miR-21 can be potentially used as an anticancer agent for the treatment of melanoma.

MicroRNA-21-Enriched Exosomes as Epigenetic Regulators in Melanomagenesis and Melanoma Progression: The Impact of Western Lifestyle Factors

DNA mutation-induced activation of RAS-BRAF-MEK-ERK signaling associated with intermittent or chronic ultraviolet (UV) irradiation cannot exclusively explain the excessive increase of malignant melanoma (MM) incidence since the 1950s. Malignant conversion of a melanocyte to an MM cell and metastatic MM is associated with a steady increase in microRNA-21 (miR-21). At the epigenetic level, miR-21 inhibits key tumor suppressors of the RAS-BRAF signaling pathway enhancing proliferation and MM progression. Increased MM cell levels of miR-21 either result from endogenous upregulation of melanocytic miR-21 expression or by uptake of miR-21-enriched exogenous exosomes. Based on epidemiological data and translational evidence, this review provides deeper insights into environmentally and metabolically induced exosomal miR-21 trafficking beyond UV-irradiation in melanomagenesis and MM progression. Sources of miR-21-enriched exosomes include UV-irradiated keratinocytes, adipocyte-derived exosomes in obesity, airway epithelium-derived exosomes generated by smoking and pollution, diet-related exosomes and inflammation-induced exosomes, which may synergistically increase the exosomal miR-21 burden of the melanocyte, the transformed MM cell and its tumor environment. Several therapeutic agents that suppress MM cell growth and proliferation attenuate miR-21 expression. These include miR-21 antagonists, metformin, kinase inhibitors, beta-blockers, vitamin D, and plant-derived bioactive compounds, which may represent new options for the prevention and treatment of MM.

Functional mechanisms of miR-192 family in cancer

By growing research on the mechanisms and functions of microRNAs (miRNAs, miRs), the role of these noncoding RNAs gained more attention in healthcare. Due to the remarkable regulatory role of miRNAs, any dysregulation in their expression causes cellular functional impairment. In recent years, it has become increasingly apparent that these small molecules contribute to development, cell differentiation, proliferation, apoptosis, and tumor growth. In many studies, the miR-192 family has been suggested as a potential prognostic and diagnostic biomarker and even as a possible therapeutic target for several cancers. However, the mechanistic effects of the miR-192 family on cancer cells are still controversial. Here, we have reviewed each family member of the miR-192 including miR-192, miR-194, and miR-215, and discussed their mechanistic roles in various cancers.

Tumor-Suppressive miR-192-5p Has Prognostic Value in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is characterized by fast tumor progression and diagnosis at advanced, inoperable stages. Previous studies could demonstrate an involvement of miR-192-5p in epigenetic regulation of visceral carcinomas. Due to contradictory results, however, the clinical utility of miR-192-5p in PDAC has yet to be determined. MiR-192-5p expression was analyzed by RT-qRT-PCR in human PDAC and benign tissue (n = 78), blood serum (n = 81) and serum exosomes (n = 74), as well as in PDAC cell lines (n = 5), chemoresistant cell clones (n = 2), and pancreatic duct cell line H6c7. Analysis of EMT-associated (epithelial-to-mesenchymal transition) proteins was performed by immunohistochemistry and Western blot. MiR-192-5p was deregulated in PDAC as compared to healthy controls (HCs), with downregulation in macrodissected tissue (p < 0.001) and upregulation in blood serum of PDAC UICC (Union for International Cancer Control) stage IV (p = 0.016) and serum exosomes of PDAC UICC stages II to IV (p < 0.001). MiR-192-5p expression in tumor tissue was significantly lower as compared to corresponding peritumoral tissue (PDAC UICC stage II: p < 0.001; PDAC UICC stage III: p = 0.024), while EMT markers ZEB1 and ZEB2 were more frequently expressed in tumor tissue as compared to peritumoral tissue, HCs, and chronic pancreatitis. Tissue-derived (AUC of 0.86; p < 0.0001) and exosomal (AUC of 0.83; p = 0.0004) miR-192-5p could differentiate between PDAC and HCs with good accuracy. Furthermore, high expression of miR-192-5p in PDAC tissue of curatively resected PDAC patients correlated with prolonged overall and recurrence-free survival in multivariate analysis. In vitro, miR-192-5p was downregulated in gemcitabine-resistant cell clones of AsPC-1 (p = 0.029). Transient transfection of MIA PaCa-2 cells with miR-192-5p mimic resulted in downregulation of ZEB2. MiR-192-5p seems to possess a tumor-suppressive role and high potential as a diagnostic and prognostic marker in PDAC.

Upregulation of miR-941 in Circulating CD14+ Monocytes Enhances Osteoclast Activation via WNT16 Inhibition in Patients with Psoriatic Arthritis

Psoriatic arthritis (PsA) is a destructive joint disease mediated by osteoclasts. MicroRNAs (miRNAs) regulate several important pathways in osteoclastogenesis. We profiled the expression of miRNAs in CD14+ monocytes from PsA patients and investigated how candidate microRNAs regulate the pathophysiology in osteoclastogenesis. The RNA from circulatory CD14+ monocytes was isolated from PsA patients, psoriasis patients without arthritis (PsO), and healthy controls (HCs). The miRNAs were initially profiled by next-generation sequencing (NGS). The candidate miRNAs revealed by NGS were validated by PCR in 40 PsA patients, 40 PsO patients, and 40 HCs. The osteoclast differentiation and its functional resorption activity were measured with or without RNA interference against the candidate miRNA. The microRNA-941 was selectively upregulated in CD14+ monocytes from PsA patients. Osteoclast development and resorption ability were increased in CD14+ monocytes from PsA patients. Inhibition of miR-941 abrogated the osteoclast development and function while increased the expression of WNT16. After successful treatment, the increased miR-941 expression in CD14+ monocytes from PsA patients was revoked. The expression of miR-941 in CD14+ monocytes is associated with PsA disease activity. MiR-941 enhances osteoclastogenesis in PsA via WNT16 repression. The miR-941 could be a potential biomarker and treatment target for PsA.

SCAMP3 Promotes Glioma Proliferation and Indicates Unfavorable Prognosis via Multiple Pathways

Introduction

The secretory carrier-associated membrane protein 3 (SCAMP3) is a component of post-Golgi membranes, functions as a protein carrier and is critical for subcellular protein transportation. Limited studies revealed an elevated expression of SCAMP3 in breast cancer and hepatocellular carcinoma; however, its role in glioma remains unknown. The aim of our study is to investigate the expression pattern and functional mechanisms of SCAMP3 in glioma.

Methods

mRNA and protein levels of SCAMP3 were examined in glioma tissues together with nontumorous brain tissues by using quantitative real-time-PCR and immunohistochemistry staining. The prognostic role of SCAMP3 in glioma was evaluated through univariate and multivariate analyses. In vitro and in vivo assays were conducted to explore the underlying mechanisms of SCAMP3-induced glioma progression.

Results

The expression level of SCAMP3 was higher in glioma tissues than that in normal brain tissues. High protein level of SCAMP3 was correlated with larger tumor size and advanced WHO grade. Glioma patients with high-SCAMP3 level had worse overall survival. In addition, SCAMP3 was defined as an independent risk factor of glioma prognosis. Cellular and xenograft studies revealed that SCAMP3 promotes glioma proliferation possibly through enhancing EGFR and mTORC1 signaling.

Discussion

Our studies revealed that high-SCAMP3 expression level was closely related to the unfavorable clinical features and poor prognosis of glioma patients. SCAMP3 may serve as an invaluable prognostic indicator and novel therapeutic target for glioma treatment.

Anticancer mechanisms of metformin: A review of the current evidence

Metformin, a US Food and Drug Administration-approved "star" drug used for diabetes mellitus type 2, has become a topic of increasing interest to researchers due to its anti-neoplastic effects. Growing evidence has demonstrated that metformin may be a promising chemotherapeutic agent, and several clinical trials of metformin use in cancer treatment are ongoing. However, the anti-neoplastic effects of metformin and its underlying mechanisms have not been fully elucidated. In this review, we present the newest findings on the anticancer activities of metformin, and highlight its diverse anticancer mechanisms. Several clinical trials, as well as the limitations of the current evidence are also demonstrated. This review explores the crucial roles of metformin and provides supporting evidence for the repurposing of metformin as a treatment of cancer.

Metformin: current clinical applications in nondiabetic patients with cancer

Metformin is one of the most commonly used first-line oral medications for type 2 diabetes mellitus. Multiple observational studies, reviewed in numerous systematic reviews, have shown that metformin treatment may not only reduce the risk of cancer but may also improve the efficacy of cancer treatment in diabetic patients. Recent studies have been conducted to determine whether a similar protective effect can be demonstrated in nondiabetic cancer patients. However, the results are controversial. The potential optimal dose, schedule, and duration of metformin treatment and the heterogeneity of histological subtypes and genotypes among cancer patients might contribute to the different clinical benefits. In addition, as the immune property of metformin was investigated, further studies of the immunomodulatory effect of metformin on cancer cells should also be taken into account to optimize its clinical use. In this review, we present and discuss the latest findings regarding the anticancer potential of metformin in nondiabetic patients with cancer.

Serum miRNA as a possible biomarker in the diagnosis of bipolar II disorder

The diagnosis of Bipolar II disorder (BD-II) is currently based on the patients' description of symptoms and clinical behavioral observations. This study explored the possibility of miRNA in peripheral blood (serum) as a specific biomarker for BD-II. We identified 6 candidate miRNAs to differentiate BD-II patients from controls using next-generation sequencing. We then examined these candidate miRNAs using real-time PCR in the first cohort (as training group) of 79 BD-II and 95 controls. A diagnostic model was built based on these candidate miRNAs and then tested on an individual testing group (BD-II: n = 20, controls: n = 20). We found that serum expression levels of miR-7-5p, miR-23b-3p, miR-142-3p, miR-221-5p, and miR-370-3p significantly increased in BD-II compared with controls in the first cohort, whereas that of miR-145-5p showed no significant difference. The diagnostic power of the identified miRNAs was further analyzed using receiver-operating characteristic (ROC). Support vector machine (SVM) measurements revealed that a combination of the significant miRNAs reached good diagnostic accuracy (AUC: 0.907). We further examined an independent testing group and the diagnostic power reached fair for BD-II (specificity = 90%, sensitivity = 85%). We constructed miRNA panels using SVM model, which may aid in the diagnosis for BD-II.

Metformin Inhibits Tumor Metastasis through Suppressing Hsp90α Secretion in an AMPKα1-PKCγ Dependent Manner

Metformin has been documented in epidemiological studies to mitigate tumor progression. Previous reports show that metformin inhibits tumor migration in several cell lines, such as MCF-7 and H1299, but the mechanisms whereby metformin exerts its inhibitory effects on tumor metastasis remain largely unknown. The secreted proteins in cancer cell-derived secretome have been reported to play important roles in tumor metastasis, but whether metformin has an effect on tumor secretome remains unclear. Here we show that metformin inhibits tumor metastasis by suppressing Hsp90α (heat shock protein 90α) secretion. Mass spectrometry (MS) analysis and functional validation identify that eHsp90α (extracellular Hsp90α) is one of the most important secreted proteins for metformin to inhibit tumor cells migration, invasion and metastasis both in vitro and in vivo. Moreover, we find that metformin inhibits Hsp90α secretion in an AMPKα1 dependent manner. Our data elucidate that AMPKα1 (AMP-activated protein kinase α1) decreases the phosphorylation level of Hsp90α by inhibiting the kinase activity of PKCγ (protein kinase Cγ), which suppresses the membrane translocation and secretion of Hsp90α. Collectively, our results illuminate that metformin inhibits tumor metastasis by suppressing Hsp90α secretion in an AMPKα1 dependent manner.

Metformin-repressed miR-381-YAP-snail axis activity disrupts NSCLC growth and metastasis

BACKGROUND

Recent evidence indicates that metformin inhibits mammalian cancer growth and metastasis through the regulation of microRNAs. Metformin regulates miR-381 stability, which plays a vital role in tumor progression. Moreover, increased YAP expression and activity induce non-small cell lung cancer (NSCLC) tumor growth and metastasis. However, the molecular mechanism underpinning how metformin-induced upregulation of miR-381 directly targets YAP or its interactions with the epithelial-mesenchymal transition (EMT) marker protein Snail in NSCLC is still unknown.

METHODS

Levels of RNA and protein were analyzed using qPCR, western blotting and immunofluorescence staining. Cellular proliferation was detected using a CCK8 assay. Cell migration and invasion were analyzed using wound healing and transwell assays. Promoter activity and transcription were investigated using the luciferase reporter assay. Chromatin immunoprecipitation was used to detect the binding of YAP to the promoter of Snail. The interaction between miR-381 and the 3'UTR of YAP mRNA was analyzed using the MS2 expression system and co-immunoprecipitation with biotin.

RESULTS

We observed that miR-381 expression is negatively correlated with YAP expression and plays an opposite role to YAP in the regulation of cellular proliferation, invasion, migration, and EMT of NSCLC cells. The miR-381 function as a tumor suppressor was significantly downregulated in lung cancer tissue specimens and cell lines, which decreased the expression of its direct target YAP. In addition, metformin decreased cell growth, migration, invasion, and EMT via up-regulation of miR-381. Moreover, YAP, which functions as a co-transcription factor, enhanced NSCLC progression and metastasis by upregulation of Snail. Snail knockdown downregulated the mesenchymal marker vimentin and upregulated the epithelial marker E-cadherin in lung cancer cells. Furthermore, miR-381, YAP, and Snail constitute the miR-381-YAP-Snail signal axis, which is repressed by metformin, and enhances cancer cell invasiveness by directly regulating EMT.

CONCLUSIONS

Metformin-induced repression of miR-381-YAP-Snail axis activity disrupts NSCLC growth and metastasis. Thus, we believe that the miR-381-YAP-Snail signal axis may be a suitable diagnostic marker and a potential therapeutic target for lung cancer.

MicroRNAs in Tumor Cell Metabolism: Roles and Therapeutic Opportunities

Dysregulated metabolism is a common feature of cancer cells and is considered a hallmark of cancer. Altered tumor-metabolism confers an adaptive advantage to cancer cells to fulfill the high energetic requirements for the maintenance of high proliferation rates, similarly, reprogramming metabolism confers the ability to grow at low oxygen concentrations and to use alternative carbon sources. These phenomena result from the dysregulated expression of diverse genes, including those encoding microRNAs (miRNAs) which are involved in several metabolic and tumorigenic pathways through its post-transcriptional-regulatory activity. Further, the identification of key actionable altered miRNA has allowed to propose novel targeted therapies to modulated tumor-metabolism. In this review, we discussed the different roles of miRNAs in cancer cell metabolism and novel miRNA-based strategies designed to target the metabolic machinery in human cancer.

Anticancer activity of metformin: a systematic review of the literature

Background

The anticancer activity of metformin has been confirmed against several cancer types in vitro and in vivo. However, the underlying mechanisms of metformin in the treatment of cancer are not fully understood. This systematic review aims to discuss the possible anticancer mechanism of action of metformin.

Method

A search through different databases was conducted, including Medline and EMBASE.

Results

A total of 96 articles were identified of which 56 were removed for duplication and 24 were excluded after reviewing the title and abstract. A total of 12 research articles were included that describe different antiproliferative mechanisms that may contribute to the antineoplastic effects of metformin.

Conclusion

This analysis discussed the potential anticancer activity of metformin and highlighted the importance of AMPK as a potential target for anticancer therapy.

Heme Oxygenase-1 Inhibition Sensitizes Human Prostate Cancer Cells towards Glucose Deprivation and Metformin-Mediated Cell Death

High levels of heme oxygenase (HO)-1 have been frequently reported in different human cancers, playing a major role in drug resistance and regulation of cancer cell redox homeostasis. Metformin (MET), a drug widely used for type 2 diabetes, has recently gained interest for treating several cancers. Recent studies indicated that the anti-proliferative effects of metformin in cancer cells are highly dependent on glucose concentration. The present work was directed to determine whether use of a specific inhibitor of HO-1 activity, alone or in combination with metformin, affected metastatic prostate cancer cell viability under different concentrations of glucose. MTT assay and the xCELLigence system were used to evaluate cell viability and cell proliferation in DU145 human prostate cancer cells. Cell apoptosis and reactive oxygen species were analyzed by flow cytometry. The activity of HO-1 was inhibited using a selective imidazole-based inhibitor; genes associated with antioxidant systems and cell death were evaluated by qRT-PCR. Our study demonstrates that metformin suppressed prostate cancer growth in vitro and increased oxidative stress. Disrupting the antioxidant HO-1 activity, especially under low glucose concentration, could be an attractive approach to potentiate metformin antineoplastic effects and could provide a biochemical basis for developing HO-1-targeting drugs against solid tumors.