The role of AMPK/mTOR signaling pathway in anticancer activity of metformin

Metformin Prevents Tumor Cell Growth and Invasion of Human Hormone Receptor-Positive Breast Cancer (HR+ BC) Cells via FOXA1 Inhibition

Women with type 2 diabetes (T2D) have a higher risk of being diagnosed with breast cancer and have worse survival than non-diabetic women if they do develop breast cancer. However, more research is needed to elucidate the biological underpinnings of these relationships. Here, we found that forkhead box A1 (FOXA1), a forkhead family transcription factor, and metformin (1,1-dimethylbiguanide hydrochloride), a medication used to treat T2D, may impact hormone-receptor-positive (HR+) breast cancer (BC) tumor cell growth and metastasis. Indeed, fourteen diabetes-associated genes are highly expressed in only three HR+ breast cancer cell lines but not the other subtypes utilizing a 53,805 gene database obtained from NCBI GEO. Among the diabetes-related genes, FOXA1, MTA3, PAK4, FGFR3, and KIF22 were highly expressed in HR+ breast cancer from 4032 breast cancer patient tissue samples using the Breast Cancer Gene Expression Omnibus. Notably, elevated FOXA1 expression correlated with poorer overall survival in patients with estrogen-receptor-positive/progesterone-receptor-positive (ER+/PR+) breast cancer. Furthermore, experiments demonstrated that loss of the FOXA1 gene inhibited tumor proliferation and invasion in vitro using MCF-7 and T47D HR+ breast cancer cell lines. Metformin, an anti-diabetic medication, significantly suppressed tumor cell growth in MCF-7 cells. Additionally, either metformin treatment or FOXA1 gene deletion enhanced tamoxifen-induced tumor growth inhibition in HR+ breast cancer cell lines within an ex vivo three-dimensional (3D) organoid model. Therefore, the diabetes-related medicine metformin and FOXA1 gene inhibition might be a new treatment for patients with HR+ breast cancer when combined with tamoxifen, an endocrine therapy.

Slow proliferation of BAP1-deficient uveal melanoma cells is associated with reduced S6 signaling and resistance to nutrient stress

Uveal melanoma (UM) is the deadliest form of eye cancer in adults. Inactivating mutations and/or loss of expression of the gene encoding BRCA1-associated protein 1 (BAP1) in UM tumors are associated with an increased risk of metastasis. To investigate the mechanisms underlying this risk, we explored the functional consequences of BAP1 deficiency. UM cell lines expressing mutant BAP1 grew more slowly than those expressing wild-type BAP1 in culture and in vivo. The ability of BAP1 reconstitution to restore cell proliferation in BAP1-deficient cells required its deubiquitylase activity. Proteomic analysis showed that BAP1-deficient cells had decreased phosphorylation of ribosomal S6 and its upstream regulator, p70S6K1, compared with both wild-type and BAP1 reconstituted cells. In turn, expression of p70S6K1 increased S6 phosphorylation and proliferation of BAP1-deficient UM cells. Consistent with these findings, BAP1 mutant primary UM tumors expressed lower amounts of p70S6K1 target genes, and S6 phosphorylation was decreased in BAP1 mutant patient-derived xenografts (PDXs), which grew more slowly than wild-type PDXs in the liver (the main metastatic site of UM) in mice. BAP1-deficient UM cells were also more resistant to amino acid starvation, which was associated with diminished phosphorylation of S6. These studies demonstrate that BAP1 deficiency slows the proliferation of UM cells through regulation of S6 phosphorylation. These characteristics may be associated with metastasis by ensuring survival during amino acid starvation.

The Anti-Diabetic Drug Metformin Suppresses Pathological Retinal Angiogenesis via Blocking the mTORC1 Signaling Pathway in Mice (Metformin Suppresses Pathological Angiogenesis)

PURPOSE

Metformin, a biguanide antihyperglycemic drug, can exert various beneficial effects in addition to its glucose-lowering effect. The effects of metformin are mainly mediated by AMP-activated protein kinase (AMPK)-dependent pathway. AMPK activation interferes with the action of the mammalian target of rapamycin complex 1 (mTORC1), and blockade of mTORC1 pathway suppresses pathological retinal angiogenesis. Therefore, in this study, we examined the effects of metformin on pathological angiogenesis and mTORC1 activity in the retinas of mice with oxygen-induced retinopathy (OIR).

METHODS

OIR was induced by exposing the mice to 80% oxygen from postnatal day (P) 7 to P10. The OIR mice were treated with metformin, rapamycin (an inhibitor of mTORC1), or the vehicle from P10 to P12 or P14. The formation of neovascular tufts, revascularization in the central avascular areas, expression of vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) 2, and phosphorylated ribosomal protein S6 (pS6), a downstream indicator of mTORC1 activity, were evaluated at P10, P13, or P15.

RESULTS

Neovascular tufts and vascular growth in the central avascular areas were observed in the retinas of P15 OIR mice. The formation of neovascular tufts, but not the revascularization in the central avascular areas, was attenuated by metformin administration from P10 to P14. Metformin had no significant inhibitory effect on the expression of VEGF and VEGFR2, but it reduced the pS6 immunoreactivity in vascular cells at the sites of angiogenesis. Rapamycin completely blocked the phosphorylation of ribosomal protein S6 and markedly reduced the formation of neovascular tufts.

CONCLUSIONS

These results suggest that metformin partially suppresses the formation of neovascular tufts on the retinal surface by blocking the mTORC1 signaling pathway. Metformin may exert beneficial effects against the progression of ocular diseases in which abnormal angiogenesis is associated with the pathogenesis.

The role of resveratrol in neurogenesis: a systematic review

CONTEXT

Resveratrol (RV) is a natural compound found in grapes, wine, berries, and peanuts and has potential health benefits-namely, neurogenesis improvement. Neurogenesis, which is the process through which new neurons or nerve cells are generated in the brain, occurs in the subventricular zone and hippocampus and is influenced by various factors. RV has been shown to increase neural stem cell proliferation and survival, improving cognitive function in hippocampus-dependent tasks. Thus, to provide a convergent and unbiased conclusion of the available evidence on the correlation between the RV and neurogenesis, a systematic review needs to be undertaken meticulously and with appropriate attention.

OBJECTIVE

This study aimed to systematically review any potential connection between the RV and neurogenesis in animal models.

DATA SOURCES AND EXTRACTION

Based on the particular selection criteria, 8 original animal studies that investigated the relationship between RV and neurogenesis were included. Studies written in English and published in peer-reviewed journals with no restrictions on the starting date of publication on August 17, 2023, were searched in the Google Scholar and PubMed databases. Furthermore, data were extracted and analyzed independently by 2 researchers and then reviewed by a third researcher, and discrepancies were resolved by consensus. This project followed PRISMA reporting standards.

DATA ANALYSIS

In the studies analyzed in this review, there is a definite correlation between RV and neurogenesis, meaning that RV intake, irrespective of the mechanisms thereof, can boost neurogenesis in both the subventricular zone and hippocampus.

CONCLUSION

This finding, albeit with some limitations, provides a plausible indication of RV's beneficial function in neurogenesis. Indeed, RV intake may result in neurogenesis benefits-namely, cognitive function, mood regulation, stress resilience, and neuroprotection, potentially preventing cognitive decline.

CircRNAs as New Therapeutic Entities and Tools for Target Identification in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a genetically extremely heterogeneous disease. Drug resistance after induction therapy is a very frequent event resulting in poor medium survival times. Therefore, the identification of new targets and treatment modalities is a medical high priority issue. We addressed our attention to circular RNAs (circRNAs), which can act as oncogenes or tumor suppressors in AML. We searched the literature (PubMed) and identified eight up-regulated and two down-regulated circ-RNAs with activity in preclinical in vivo models. In addition, we identified twenty-two up-regulated and four down-regulated circRNAs with activity in preclinical in vitro systems, but pending in vivo activity. Up-regulated RNAs are potential targets for si- or shRNA-based approaches, and down-regulated circRNAs can be reconstituted by replacement therapy to achieve a therapeutic benefit in preclinical systems. The up-regulated targets can be tackled with small molecules, antibody-based entities, or other modes of intervention. For down-regulated targets, up-regulators must be identified. The ranking of the identified circRNAs with respect to therapy of AML will depend on further target validation experiments.

Survival Impact of Combined Biguanide and Temozolomide in Glioblastoma Preclinical Models: A Systematic Review and Meta-Analysis

BACKGROUND

Glioblastoma (GBM) is an aggressive tumor known for its poor prognosis. Despite extensive research into its molecular and clinical aspects, the current management strategies have shown limited efficacy in improving survival rate. Despite some preclinical studies exploring the combination of temozolomide (TMZ) with biguanides such as metformin (MET) and others, the potential benefits of this combination remain uncertain. The aim of this study is to evaluate the overall survival (OS) in GBM murine-models treated with a combination of TMZ + biguanide compared to those treated with TMZ alone.

METHODS

We systematically searched Medline, Embase, and Lilacs databases for studies comparing TMZ + biguanide versus TMZ alone in GBM models and reporting OS data. The mean difference (MD) with 95% confidence interval and random-effects model was adopted.

RESULTS

Nine studies were included in this systematic review. The meta-analysis comprised 6 studies involving 85 rat-models, with 45 subjects undergoing combined-treatment. GBM-murine models treated with TMZ + biguanide exhibited notably superior OS rates compared to those who received TMZ alone, showing an MD of 21.0 days (6.9-35.0). Within the subgroup of orthotopic models, the OS was also significantly better in combination-therapy with an MD of 23.7 days (6.5-40.9). Similarly, in the subgroup where MET was used as biguanide therapy, TMZ + MET demonstrated a significant increase in OS, with an MD of 27.4 days (6.0-48.8). In immunocompromised models, the combination-therapy also exhibited higher survival rates, with an MD of 13 days (9.4-16.6).

CONCLUSIONS

This systematic review and meta-analysis provide compelling evidence regarding the beneficial effects of TMZ + biguanide in GBM models compared with TMZ alone, resulting in a significant improvement in OS.

The mechanisms of action of metformin on head and neck cancer in the pre-clinical setting: a scoping review

This scoping review identifies the mechanistic pathways of metformin when used to treat head and neck cancer cells, in the pre-clinical setting. Understanding the underlying mechanisms will inform future experimental designs exploring metformin as a potential adjuvant for head and neck cancer. This scoping review was conducted according to the Joanna-Briggs Institute framework. A structured search identified 1288 studies, of which 52 studies fulfilled the eligibility screen. The studies are presented in themes addressing hallmarks of cancer. Most of the studies demonstrated encouraging anti-proliferative effects in vitro and reduced tumor weight and volume in animal models. However, a few studies have cautioned the use of metformin which supported cancer cell growth under certain conditions.

Efficacy of metformin and electrical pulses in breast cancer MDA-MB-231 cells

Aim

Triple-negative breast cancer (TNBC) is a very aggressive subset of breast cancer, with limited treatment options, due to the lack of three commonly targeted receptors, which merits the need for novel treatments for TNBC. Towards this need, the use of metformin (Met), the most widely used type-2 diabetes drug worldwide, was explored as a repurposed anticancer agent. Cancer being a metabolic disease, the modulation of two crucial metabolites, glucose, and reactive oxygen species (ROS), is studied in MDA-MB-231 TNBC cells, using Met in the presence of electrical pulses (EP) to enhance the drug efficacy.

Methods

MDA-MB-231, human TNBC cells were treated with Met in the presence of EP, with various concentrations Met of 1 mmol/L, 2.5 mmol/L, 5 mmol/L, and 10 mmol/L. EP of 500 V/cm, 800 V/cm, and 1,000 V/cm (with a pulse width of 100 µs at 1 s intervals) were applied to TNBC and the impact of these two treatments was studied. Various assays, including cell viability, microscopic inspection, glucose, ROS, and wound healing assay, were performed to characterize the response of the cells to the combination treatment.

Results

Combining 1,000 V/cm with 5 mmol/L Met yielded cell viability as low as 42.6% at 24 h. The glucose level was reduced by 5.60-fold and the ROS levels were increased by 9.56-fold compared to the control, leading to apoptotic cell death.

Conclusions

The results indicate the enhanced anticancer effect of Met in the presence of electric pulses. The cell growth is inhibited by suppressing glucose levels and elevated ROS. This shows a synergistic interplay between electroporation, Met, glucose, and ROS metabolic alterations. The results show promises for combinational therapy in TNBC patients.

Piperlongumine based nanomedicine impairs glycolytic metabolism in triple negative breast cancer stem cells through modulation of GAPDH & FBP1

BACKGROUND

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and exhibits high rate of chemoresistance, metastasis, and relapse. This can be attributed to the failure of conventional therapeutics to target a sub-population of slow cycling or quiescent cells called as cancer stem cells (CSCs). Therefore, elimination of CSCs is essential for effective TNBC treatment.

PURPOSE

Research suggests that breast CSCs exhibit elevated glycolytic metabolism which directly contributes in maintenance of stemness, self-renewability and chemoresistance as well as in tumor progression. Therefore, this study aimed to target rewired metabolism which can serve as Achilles heel for CSCs population and have far reaching effect in TNBC treatment.

METHODS

We used two preclinical models, zebrafish and nude mice to evaluate the fate of nanoparticles as well as the therapeutic efficacy of both piperlongumine (PL) and its nanomedicine (PL-NPs).

RESULTS

In this context, we explored a phytochemical piperlongumine (PL) which has potent anti-cancer properties but poor pharmacokinetics impedes its clinical translation. So, we developed PLGA based nanomedicine for PL (PL-NPs), and demonstrated that it overcomes the pharmacokinetic limitations of PL, along with imparting advantages of selective tumor targeting through Enhanced Permeability and Retention (EPR) effect in zebrafish xenograft model. Further, we demonstrated that PL-NPs efficiently inhibit glycolysis in CSCs through inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by modulating glutathione S-transferase pi 1 (GSTP1) and upregulation of fructose-1,6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis. We also illustrated that inhibition of glycolysis results in overall tumor regression in two preclinical models.

CONCLUSION

This study discusses novel mechanism of action by which PL acts on CSCSs. Taken together our study provides insight into development of PL based nanomedicine which could be exploited in clinics to achieve complete eradication of TNBC by targeting CSCs.

Identification of a glycolysis-related miRNA Signature for Predicting Breast cancer Survival

Breast cancer (BC) is a common type of cancer and has a poor prognosis. In this study, we collected the mRNA and miRNA expression profiles of BC patients were obtained from The Cancer Genome Atlas (TCGA) to explore a novel prognostic strategy for BC patients using bioinformatics tools. We found that six glycolysis-related miRNAs (GRmiRs, including hsa-mir-1247, hsa-mir148b, hsa-mir-133a-2, has-mir-1307, hsa-mir-195 and hsa-mir-1258) were correlated with prognosis of BC samples. The risk score model was established based on 6 prognosis-associated GRmiRs. The outcome of high risk group was significantly poorer. Cox regression analysis showed that risk score was an independent prognostic factor. Differentially expressed genes identified between high and low risk groups were mainly enriched in inflammation and immune-related signaling pathways. The proportion of infiltration of 12 kinds of immune cells in high and low risk groups were significantly different. Risk score was closely associated with many immune indexes. Multiple DEGRGs and miRNAs were associated with drugs. In conclusion, glycolysis-related miRNA signature effectively predicts BC prognosis.

Alisol A 24-acetate ameliorates osteoarthritis progression by inhibiting reactive oxygen species and inflammatory response through the AMPK/mTOR pathway

INTRODUCTION

Osteoarthritis is a degenerative knee joint disease featured with articular cartilage degeneration and inflammation. Alisol A 24-acetate (ALA-24A) is an active triterpene that has antioxidant and anti-inflammatory pharmacological properties. However, its effect and molecular mechanism on osteoarthritis progression have not been reported.

METHODS

IL-1β-induced chondrocyte injury model and monosodium iodoacetate (MIA)-induced rat osteoarthritis model were used. The protective effects of ALA-24A on osteoarthritis were evaluated by determining cell viability, extracellular matrix (ECM) degradation, inflammatory response and oxidative stress using CCK-8 assay, Western blot, ELISA, and DCFH-DA fluorescent probe. The severity and matrix degradation of articular cartilage were assessed by histopathological and immunohistochemical examination.

RESULTS

We found that ALA-24A attenuated IL-1β-induced cell viability inhibition Moreover, ALA-24A suppressed expression levels of ECM degradation-related genes ADAMTS5 and MMP13, and promoted expression levels of ECM synthesis-related genes Aggrecan and Collagen II. In addition, ALA-24A treatment decreased reactive oxygen species (ROS) production and increased antioxidant enzymes (SOD, CAT, and GSH-px) activities, while increased MDA levels. The inflammatory levels of NO, PGE2, TNF-α, and IL-6 were also reduced following treatment with ALA-24A. Our data also revealed that ALA-24A treatment triggered p-AMPK upregulation and p-mTOR downregulation. In rat osteoarthritis model, ALA-24A treatment significantly alleviated the severity and matrix degradation of articular cartilage comparted with model group.

CONCLUSIONS

Our findings suggested a protective role of ALA-24A against osteoarthritis by inhibiting ROS and inflammatory response. Furthermore, ALA-24A might be a promising therapeutic option for osteoarthritis treatment.

The role of exercise in obesity-related cancers: Current evidence and biological mechanisms

Cancer ranks among the five leading causes of death in almost all countries and has important repercussions for individual and public health, the healthcare system, and society in general. Obesity increases the incidence of many types of cancer, but growing evidence suggests that physical activity may decrease risk for developing a variety of obesity-related cancer types, and, in some cases, may improve cancer prognosis and mortality rates. This review summarizes recent evidence on the effect of physical activity on obesity-related cancer prevention and survival. For some cancers, including breast, colorectal, and endometrial cancer, there is strong evidence for a preventative effect of exercise, but for many others, including gallbladder and kidney cancer, and multiple myeloma, evidence is inconsistent or largely lacking. Though many potential mechanisms have been proposed to explain the onco-protective effect of exercise, including improved insulin sensitivity, alterations in sex hormone availability, improved immune function and inflammation, myokine secretion, and modulation of intracellular signaling at the level of AMP kinase, the exact mechanism(s) of action within each cancer subtype remains poorly defined. Overall, a deeper understanding of how exercise can help against cancer and of the exercise parameters that can be altered to optimize exercise prescription is necessary and should be the subject of future investigation.

Glucagon-like peptide-1 receptor regulates receptor of advanced glycation end products in high glucose-treated rat mesangial cells

BACKGROUND

Hyperglycemia-induced advanced glycation end products (AGEs) and receptor for AGEs (RAGEs) play major roles in diabetic nephropathy progression. In previous study, both glucagon-like peptide-1 (GLP-1) and peroxisome proliferator-activated receptors delta (PPARδ) agonists were shown to have anti-inflammatory effect on AGE-treated rat mesangial cells (RMCs). The interaction among PPARδ agonists, GLP-1, and AGE-RAGE axis is, however, still unclear.

METHODS

In this study, the individual and synergic effect of PPARδ agonist (L-165 041) and siRNA of GLP-1 receptor (GLP-1R) on the expression of GLP-1, GLP-1R, RAGE, and cell viability in AGE-treated RMCs were investigated.

RESULTS

L-165 041 enhanced GLP-1R mRNA and protein expression only in the presence of AGE. The expression of RAGE mRNA and protein was enhanced by AGE, attenuated by L-165 041, and siRNA of GLP-1R reversed L-165 041-induced inhibition. Cell viability was also inhibited by AGE. L-165 041 attenuated AGE-induced inhibition and siRNA GLP-1R diminished L-165 041 effect.

CONCLUSION

PPARδ agonists increase GLP-1R expression on RMC in the presence of AGE. PPARδ agonists also attenuate AGE-induced upregulated RAGE expression and downregulated cell viability. The effect of PPARδ agonists needs the cooperation of GLP-1R activation.

Therapeutic metformin concentrations positively regulate proliferation in endometrial epithelial cells via mTOR activation and augmented mitochondrial strength

Metformin, an antidiabetic drug, has recently been repositioned in the treatment of several nondiabetic disorders, including reproductive disorders such as polycystic ovarian syndrome, where it improves endometrial functions. In vitro studies employing supratherapeutic concentrations (5-20 mmol/L) of metformin have reported antiproliferative effects on endometrial epithelial and stromal cells. However, animal and human studies have revealed that therapeutic serum concentrations of metformin range between 20 and 70 µmol/L. In the present study, the effect of therapeutic concentrations of metformin was studied on endometrial epithelial cells (EECs). Therapeutic concentrations of metformin induced proliferation in Ishikawa and HEC-1A cells. The proliferation of EECs was found to be mammalian target of rapamycin (mTOR) dependent. Interestingly, therapeutic metformin concentrations were not able to activate the classical AMP-activated protein kinase (AMPK) signaling. On the contrary, supratherapeutic metformin concentration (10 mmol/L) inhibited mTOR and activated AMPK signaling. Microarray analysis of metformin-treated HEC-1A cells revealed dose-dependent differential effects on biological pathways associated with translation, ribosomal RNA processing, mitochondrial translation, and cell proliferation. Therapeutic concentrations of metformin upregulated mitochondrial number as demonstrated by increased MitoTracker^™ Red staining and enhanced succinate dehydrogenase expression; however, higher concentration (10 mmol/L) abrogated the same. Our results suggest that therapeutic concentrations of metformin augment mitochondrial strength and induce mTOR-dependent endometrial cell proliferation.

Caffeic Acid and Diseases-Mechanisms of Action

Caffeic acid belongs to the polyphenol compounds we consume daily, often in the form of coffee. Even though it is less explored than caffeic acid phenethyl ester, it still has many positive effects on human health. Caffeic acid can affect cancer, diabetes, atherosclerosis, Alzheimer's disease, or bacterial and viral infections. This review focuses on the molecular mechanisms of how caffeic acid achieves its effects.

PTEN mutations as predictive marker for the high-grade endometrial cancer development in slovak women

Endometrial carcinoma (ECa) is one of the most common neoplasia of the female genital tract. The phosphatase and tensin (PTEN) homolog is the most frequently mutated tumor suppressor gene in endometrial carcinoma. PTEN encodes a phosphatase, a key regulatory enzyme involved in a signal transduction pathway that regulates cell growth, migration and apoptosis. The study evaluates an association between the morphological appearance of endometrial hyperplasia and ECa, and the presence of PTEN variations, PTEN protein level and intracellular localization. A total of 67 archived formalin-fixed and paraffin-embedded human biopsy tissue specimens with normal proliferative and secretory endometrium, endometrial hyperplasia without atypia and endometrial atypical hyperplasia, endometrioid the grade G1 and G3 and serous subtype of ECa were evaluated by sequencing for the presence of mutations in coding regions of PTEN gene of endometrial epithelial cells. The PTEN gene expression and intercellular localization of PTEN protein were evaluated immunohistochemically by immunoreactive score (IRS). PTEN mutation spectrum in endometrial carcinoma was identified for Slovak population. Twenty-eight non-silent mutations were identified in PTEN, twelve of them being novel, not annotated in Catalogue of Somatic Mutations in Cancer. Higher frequency of PTEN mutations was observed in serous carcinoma compared to global average. No correlation was observed between samples IRS, PTEN cellular localization and identified mutations. PTEN sequencing can be beneficial for patients considering prognosis of disease and sensitivity to treatment.

PTEN mutations as predictive marker for the high-grade endometrial cancer development in slovak women

Endometrial carcinoma (ECa) is one of the most common neoplasia of the female genital tract. The phosphatase and tensin (PTEN) homolog is the most frequently mutated tumor suppressor gene in endometrial carcinoma. PTEN encodes a phosphatase, a key regulatory enzyme involved in a signal transduction pathway that regulates cell growth, migration and apoptosis. The study evaluates an association between the morphological appearance of endometrial hyperplasia and ECa, and the presence of PTEN variations, PTEN protein´s level and intracellular localization. A total of 67 archived formalin-fixed and paraffin-embedded human biopsy tissue specimens with normal proliferative and secretory endometrium, endometrial hyperplasia without atypia and endometrial atypical hyperplasia, endometrioid the grade G1 and G3 and serous subtype of ECa were evaluated by sequencing for the presence of mutations in coding regions of PTEN gene of endometrial epithelial cells. The PTEN gene expression and intercellular localization of PTEN protein were evaluated immunohistochemically by immunoreactive score (IRS). PTEN mutation spectrum in endometrial carcinoma was identified for Slovak population. 28 non-silent mutations were identified in PTEN, twelve of them were novel, not annotated in Catalogue of Somatic Mutations in Cancer. Higher frequency of PTEN mutations was observed in serous carcinoma compared to global average. No correlation was observed between samples´ IRS, PTEN cellular localization and identified mutations. PTEN sequencing can be beneficial for patients considering prognosis of disease and sensitivity to treatment.

Recent advances to enhance the immunomodulatory potential of mesenchymal stem cells

Considering the unique therapeutic potential of mesenchymal stem cells (MSCs), including their immunosuppressive and immunomodulatory properties as well as their ability to improve tissue regeneration, these cells have attracted the attention of scientists and clinicians for the treatment of different inflammatory and immune system mediated disorders. However, various clinical trials using MSCs for the therapeutic purpose are conflicting and differ from the results of promising preclinical studies. This inconsistency is caused by several factors such as poor migration and homing capacities, low survival rate, low level of proliferation and differentiation, and donor-dependent variation of the cells. Enhancement and retention of persistent therapeutic effects of the cells remain a challenge to overcome in MSC-based therapy. In this review, we summarized various approaches to enhance the clinical outcomes of MSC-based therapy as well as revised current and future perspectives for the creation of cellular products with improved potential for diverse clinical applications.

Will We Unlock the Benefit of Metformin for Patients with Lung Cancer? Lessons from Current Evidence and New Hypotheses

Metformin has been under basic and clinical study as an oncological repurposing pharmacological agent for several years, stemming from observational studies which consistently evidenced that subjects who were treated with metformin had a reduced risk for development of cancer throughout their lives, as well as improved survival outcomes when diagnosed with neoplastic diseases. As a result, several basic science studies have attempted to dissect the relationship between metformin’s metabolic mechanism of action and antineoplastic cellular signaling pathways. Evidence in this regard was compelling enough that a myriad of randomized clinical trials was planned and conducted in order to establish the effect of metformin treatment for patients with diverse neoplasms, including lung cancer. As with most novel antineoplastic agents, early results from these studies have been mostly discouraging, though a recent analysis that incorporated body mass index may provide significant information regarding which patient subgroups might derive the most benefit from the addition of metformin to their anticancer treatment. Much in line with the current pipeline for anticancer agents, it appears that the benefit of metformin may be circumscribed to a specific patient subgroup. If so, addition of metformin to antineoplastic agents could prove one of the most cost-effective interventions proposed in the context of precision oncology. Currently published reviews mostly rely on a widely questioned mechanism of action by metformin, which fails to consider the differential effects of the drug in lean vs. obese subjects. In this review, we analyze the pre-clinical and clinical information available to date regarding the use of metformin in various subtypes of lung cancer and, further, we present evidence as to the differential metabolic effects of metformin in lean and obese subjects where, paradoxically, the obese subjects have reported more benefit with the addition of metformin treatment. The novel mechanisms of action described for this biguanide may explain the different results observed in clinical trials published in the last decade. Lastly, we present novel hypothesis regarding potential biomarkers to identify who might reap benefit from this intervention, including the role of prolyl hydroxylase domain 3 (PHD3) expression to modify metabolic phenotypes in malignant diseases.

Metformin and Cancer, an Ambiguanidous Relationship

The deregulation of energetic and cellular metabolism is a signature of cancer cells. Thus, drugs targeting cancer cell metabolism may have promising therapeutic potential. Previous reports demonstrate that the widely used normoglycemic agent, metformin, can decrease the risk of cancer in type 2 diabetics and inhibit cell growth in various cancers, including pancreatic, colon, prostate, ovarian, and breast cancer. While metformin is a known adenosine monophosphate-activated protein kinase (AMPK) agonist and an inhibitor of the electron transport chain complex I, its mechanism of action in cancer cells as well as its effect on cancer metabolism is not clearly established. In this review, we will give an update on the role of metformin as an antitumoral agent and detail relevant evidence on the potential use and mechanisms of action of metformin in cancer. Analyzing antitumoral, signaling, and metabolic impacts of metformin on cancer cells may provide promising new therapeutic strategies in oncology.

Metformin induces myeloma cells necrosis and apoptosis and it is considered for therapeutic use

Accumulating evidence, especially in solid tumor, indicated that metformin possessed the potential ability in the proliferation of cancer cells. However, its effects on myeloma cells were relatively rarely clarified. To evaluate the anti-cancer effects of metformin against dexamethasone-resistant and -sensitive myeloma cells. The effects of metformin on myeloma cell lines, including dexamethasone-resistant U266, H929, RPMI 8226 and dexamethasone-sensitive MM.1s, were investigated using the cell counting kit-8 assay for cell proliferation. Apoptosis, necrosis, cell cycle arrest, and cell death mechanisms were explored via flow cytometry (FCM) and Western blot. In addition, the anti-myeloma activity was evaluated in vivo via non-obese diabetic/severe combined immunodeficiency xenograft mouse models. Metformin inhibited proliferation in a dose and time-dependent manner in all the cell lines, while dexamethasone only affected the viability of MM1.s cells. The FCM detection displayed that metformin induced apoptosis in H929, RPMI8226 and MM.1s cells, while for U266 cells, it induced necrosis with Annexin V^-/Propidium iodide⁺. The cell cycle assays showed that metformin arrested G0/G1 phase of H929 and MM.1s cells, or G2/M phase of RPMI8226 cells, but showed no effect on U226 cells. Western blotting analyses demonstrated that the apoptosis-related protein of cleaved caspase 3 was activated; the expressions of Mcl-1, IGF-1R, PI3K, pAKT, and pmTOR proteins were inhibited by metformin in H929, RPMI8226, and MM.1s cells. The necrosis-related protein of iNOS increased in U266 cells while metformin treated. In vivo assay indicated metformin decreased U266 and H929 growth in bone marrow, and thus prolonged mice survival. These data suggested that metformin inhibited the proliferation of myeloma cells via inducing necrosis and apoptosis. This finding indicated that metformin may be served as a potent adjuvant in treating multiple myeloma.

Metformin and MiR-365 synergistically promote the apoptosis of gastric cancer cells via MiR-365-PTEN-AMPK axis

Metformin is an oral biguanide used to treat diabetes. Recent study showed it may interfere was related to cancer progression and has a positive effect on cancer prevention and treatment, which attracts a new hot research topic. Here we show that Metformin suppressed the proliferation but induced apoptosis of gastric cells. Notably, Metformin enhanced gastriccell apoptosis via modulating AMPK signaling. Furthermore, Metformin and miR-365 synergistically promote the apoptosis of gastric cancer cells by miR-365-PTEN-AMPK axis. Our study unraveled a novel signaling axis in the regulation in gastric cancer, which could be amplified by the application of metformin. The new effect of metformin potentiates its novel therapeutic application in the future. AVAILABILITY OF DATA AND MATERIALS: The data generated during this study are included in this article and its supplementary information files are available from the corresponding author on reasonable request.

Signaling Pathways Related to Oxidative Stress in Diabetic Cardiomyopathy

Diabetes is a chronic metabolic disease that is increasing in prevalence and causes many complications. Diabetic cardiomyopathy (DCM) is a complication of diabetes that is associated with high mortality, but it is not well defined. Nevertheless, it is generally accepted that DCM refers to a clinical disease that occurs in patients with diabetes and involves ventricular dysfunction, in the absence of other cardiovascular diseases, such as coronary atherosclerotic heart disease, hypertension, or valvular heart disease. However, it is currently uncertain whether the pathogenesis of DCM is directly attributable to metabolic dysfunction or secondary to diabetic microangiopathy. Oxidative stress (OS) is considered to be a key component of its pathogenesis. The production of reactive oxygen species (ROS) in cardiomyocytes is a vicious circle, resulting in further production of ROS, mitochondrial DNA damage, lipid peroxidation, and the post-translational modification of proteins, as well as inflammation, cardiac hypertrophy and fibrosis, ultimately leading to cell death and cardiac dysfunction. ROS have been shown to affect various signaling pathways involved in the development of DCM. For instance, OS causes metabolic disorders by affecting the regulation of PPARα, AMPK/mTOR, and SIRT3/FOXO3a. Furthermore, OS participates in inflammation mediated by the NF-κB pathway, NLRP3 inflammasome, and the TLR4 pathway. OS also promotes TGF-β-, Rho-ROCK-, and Notch-mediated cardiac remodeling, and is involved in the regulation of calcium homeostasis, which impairs ATP production and causes ROS overproduction. In this review, we summarize the signaling pathways that link OS to DCM, with the intention of identifying appropriate targets and new antioxidant therapies for DCM.