Metformin promotes apoptosis in primary breast cancer cells by downregulation of cyclin D1 and upregulation of P53 through an AMPK-alpha independent mechanism

Enhancing the anticancer potential of metformin: fabrication of efficient nanospanlastics, in vitro cytotoxic studies on HEP-2 cells and reactome enhanced pathway analysis

Metformin (MET), an oral antidiabetic drug, was reported to possess promising anticancer effects. We hypothesized that MET encapsulation in unique nanospanlastics would enhance its anticancer potential against HEP-2 cells. Our results showed the successful fabrication of Nano-MET spanlastics (d = 232.10 ± 0.20 nm; PDI = 0.25 ± 0.11; zeta potential = (-) 44.50 ± 0.96; drug content = 99.90 ± 0.11 and entrapment efficiency = 88.01 ± 2.50%). MTT assay revealed the enhanced Nano-MET cytotoxicity over MET with a calculated IC50 of 50 μg/mL and > 500 μg/mL, respectively. Annexin V/PI apoptosis assay showed that Nano-MET significantly decreased the percentage of live cells from 95.49 to 93.70 compared to MET and increased the percentage of cells arrested in the G0/G1 phase by 8.38%. Moreover, Nano-MET downregulated BCL-2 and upregulated BAX protein levels by 1.57 and 1.88 folds, respectively. RT-qPCR revealed that Nano-MET caused a significant 13.75, 4.15, and 2.23-fold increase in caspase-3, -8, and - 9 levels as well as a 100 and 43.47-fold decrease in cyclin D1 and mTOR levels, respectively. The proliferation marker Ki67 immunofluorescent staining revealed a 3-fold decrease in positive cells in Nano-MET compared to the control. Utilizing the combined Pathway-Enrichment Analysis (PEA) and Reactome analysis indicated high enrichment of certain pathways including nucleotides metabolism, Nudix-type hydrolase enzymes, carbon dioxide hydration, hemostasis, and the innate immune system. In summary, our results confirm MET cytotoxicity enhancement by its encapsulation in nanospanlastics. We also highlight, using PEA, that MET can modulate multiple pathways implicated in carcinogenesis.

GTF2E2 downregulated by miR-340-5p inhibits the malignant progression of glioblastoma

Glioblastoma is the most common malignant tumor in the central nervous system. The general transcription factor IIE subunit beta (GTF2E2) is crucial for physiological and pathological functions, but its roles in the malignant biological function of glioma remain ambiguous. CCK-8, colony formation assays, TUNEL assays, cell migration assays, wound-healing assays, and xenograft model were established to investigate the biological functions of GTF2E2 both in vitro and in vivo. GTF2E2 was overexpressed in glioma and was associated with poor prognosis of glioma patients. Biological functions of GTF2E2 were investigated both in vitro and in vi0vo by multiple experiments. Moreover, we explored the possible mechanisms of GTF2E2. In our results, we demonstrated that GTF2E2 could be regulated by miR-340-5p directly or indirectly. CCND1 was transcriptionally affected by GTF2E2 and glioma progression was then regulated. Our data presented the overexpression of GTF2E2 in glioma and indicated the association between GTF2E2 and glioma prognosis. GTF2E2 was found to be regulated by miR-340-5p and thus affect downstream gene expressions and glioma progression. Our results indicate that GTF2E2 might be a potential target in the diagnosis and treatments of glioblastoma.

ARHGAP44-mediated regulation of the p53/C-myc/Cyclin D1 pathway in modulating the malignant biological behavior of osteosarcoma cells

OBJECTIVE

Osteosarcoma is a rare primary malignant tumor of the bone characterized by poor survival rates, owing to its unclear pathogenesis. Rho GTPase-activating protein 44 (ARHGAP44), which belongs to the Rho GTPase-activating protein family, has promising applications in the targeted therapy of tumors. Therefore, this study aimed to investigate the biological function of ARHGAP44 in osteosarcoma and its possible application as a therapeutic target.

METHODS

The expression level of ARHGAP44 in osteosarcoma and its relationship with tumor prognosis were detected using Gene Expression Omnibus database analysis and immunohistochemical staining of clinical specimens. The cell model of ARHGAP44 knockdown was constructed, and the effects of this gene on the malignant biological behavior of osteosarcoma cells were investigated using CCK-8, clone formation, transwell invasion, wound healing, and flow cytometry assays. Western blotting was performed to detect the expression of ARHGAP44, p53, C-myc, and Cyclin D1 in osteosarcoma.

RESULTS

Biogenic analysis showed that ARHGAP44 was highly expressed in osteosarcoma. This result was associated with poor tumor prognosis and negatively correlated with the expression of the tumor suppressor gene p53. Immunohistochemistry and western blotting revealed significantly upregulated expression of ARHGAP44 in osteosarcoma tissues. Additionally, Kaplan-Meier analysis of clinical specimens suggested that ARHGAP44 was negatively correlated with tumor prognosis. CCK-8, clone formation, transwell invasion, wound healing, and flow cytometry assays showed that downregulation of ARHGAP44 expression significantly reduced the malignant biological behavior of osteosarcoma cells. Furthermore, western blotting showed that the expression level of p53 in osteosarcoma cells was significantly increased after the downregulation of ARHGAP44 expression, whereas the expression of C-myc and Cyclin D1 was significantly decreased compared with that in the control group.

CONCLUSION

ARHGAP44 was highly expressed in osteosarcoma and was negatively correlated with its prognosis. The downregulation of ARHGAP44 expression reduced the malignant biological behavior of osteosarcoma cells. These findings suggest that the downregulation of ARHGAP44 expression inhibits the malignant progression of osteosarcoma by regulating the p53/C-myc/Cyclin D1 pathway, demonstrating the potential of ARHGAP44 as a therapeutic target for osteosarcoma.

Metformin and HER2-positive breast cancer: Mechanisms and therapeutic implications

Due to the strong association between diabetes and cancer incidents, several anti-diabetic drugs, including metformin, have been examined for their anticancer activity. Metformin is a biguanide antihyperglycemic agent used as a first-line drug for type II diabetes mellitus. It exhibits anticancer activity by impacting different molecular pathways, such as AMP-inducible protein kinase (AMPK)-dependent and AMPK-independent pathways. Additionally, Metformin indirectly inhibits IGF-1R signaling, which is highly activated in breast malignancy. On the other hand, breast cancer is one of the major causes of cancer-related morbidity and mortality worldwide, where the human epidermal growth factor receptor-positive (HER2-positive) subtype is one of the most aggressive ones with a high rate of lymph node metastasis. In this review, we summarize the association between diabetes and human cancer, listing recent evidence of metformin's anticancer activity. A special focus is dedicated to HER2-positive breast cancer with regards to the interaction between HER2 and IGF-1R. Then, we discuss combination therapy strategies of metformin and other anti-diabetic drugs in HER2-positive breast cancer.

Keratin19 promotes pancreatic cancer progression and poor prognosis via activating the Hedgehog pathway

Pancreatic cancer is a serious threat to human health, with strong invasiveness, rapid progression and poor prognosis. Tumors expressing keratin 19 (K19) have stronger invasiveness and a worse prognosis. However, the role and mechanism of K19 in pancreatic cancer have remained largely elusive. In the present study, K19 expression was detected in pancreatic cancer tissues, its effect on proliferation, apoptosis and metastasis of pancreatic cancer at the cellular, in vivo preclinical and clinical levels was evaluated and its effect on the Hedgehog pathway was analyzed. K19 was significantly overexpressed in pancreatic cancer, promoted pancreatic cancer proliferation and metastasis, inhibited tumor cell apoptosis and was associated with poor prognosis. Mechanistically, these effects were mediated through the activation of the Hedgehog pathway. In conclusion, K19 may be a novel target molecule for pancreatic cancer treatment.

Metformin: A promising drug for human cancers

Small-molecule chemical drugs are of great significance for tumor-targeted and individualized therapies. However, the development of new small-molecule drugs, from basic experimental research and clinical trials to final application in clinical practice, is a long process that has a high cost. It takes at least 5 years for most drugs to be developed in the laboratory to prove their effectiveness and safety. Compared with the development of new drugs, repurposing traditional non-tumor drugs can be a shortcut. Metformin is a good model for a new use of an old drug. In recent years, the antitumor efficacy of metformin has attracted much attention. Epidemiological data and in vivo, and in vitro experiments have shown that metformin can reduce the incidence of cancer in patients with diabetes and has a strong antagonistic effect on metabolism-related tumors. Recent studies have shown that metformin can induce autophagy in esophageal cancer cells, mainly by inhibiting inflammatory signaling pathways. In recent years, studies have shown that the antitumor functions and mechanisms of metformin are multifaceted. The present study aims to review the application of metformin in tumor prevention and treatment.

In vitro ve in silico analizi ile metforminin meme tümörü hücrelerinde protein profili üzerindeki etkinliği

Aim: This study aimed to uncover the varieties in protein profiles of Met in breast tumor (BT) cells by assessment of in vitro and in silico analysis. Materials and Methods: Here, the cells obtained from mastectomy patients were cultured, the effective Met-dose was determined as 25 mM through cell viability and BrdU tests. Protein identification in the breast tumor cells was implemented by employing LC-MS/MS technology. Results: The expression of SSR3, THAP3, FTH1, NEFM, ANP32A, ANP32B, KRT7 proteins was significantly decreased whereas the GARS protein increased in the 25 mM Met group compared to the Non-Met (0 mM) control group. In silico analysis, we analyzed the probable interactions of all these proteins with each other and other proteins, to evaluate the analysis of the larger protein network, and which metabolic pathway proteins are involved in. Conclusion: The stated proteomics analysis in our study proposes a better understanding of the prognosis of breast cancer and future studies to investigate the effect of metformin in this field on proteomic pathways in other sorts of cancer.

Metformin Induces PRODH/POX-Dependent Apoptosis in Breast Cancer Cells

Although the antineoplastic activity of metformin (MET) is well established, the underlying mechanism of the activity is not understood. Since MET activates AMP kinase (AMPK) and proline dehydrogenase/proline oxidase (PRODH/POX) is stimulated by AMPK ligands (implicated in the regulation of cancer cell survival/apoptosis), the effect of MET on PRODH/POX-dependent apoptosis in wild-type MCF-7 cells (MCF-7^WT) and POX knockdown MCF-7 cells (MCF-7^crPOX cells) was studied. PRODH/POX catalyzes proline degradation generating ROS-induced apoptosis or autophagy. Availability of proline for PRODH/POX functions is regulated by the activity of prolidase (enzyme releasing proline from imidodipeptides), collagen biosynthesis (process consuming proline), and metabolism of proline, ornithine, and glutamic acid. We have found that MET is cytotoxic for MCF-7 cells (IC50∼17 mM), and to the lower extent for MCF-7^crPOX cells (IC50∼28 mM). In MCF-7^WT cells, the effect was accompanied by the inhibition of DNA biosynthesis, collagen biosynthesis, stimulation of ROS formation, AMPKα phosphorylation, and expression of prolidase, p53, caspase 8, caspase 9, and cleaved PARP. In MET-treated MCF-7^crPOX cells, the processes were less affected than in MCF-7^WT cells and the expression of caspase 9 was decreased, while cleaved caspase 8 and cleaved PARP were not detected. The effects were accompanied by an increase in the prolidase activity and proline concentration. The mechanism for MET-induced apoptosis involves the up-regulation of prolidase activity and a decrease in collagen biosynthesis contributing to an increase in the concentration of substrate (proline) for PRODH/POX-dependent ROS formation and activation of caspases −9 and −8. The data suggest that PRODH/POX participates in the MET-induced intrinsic and extrinsic apoptosis in MCF-7 cells.

Association of Diabetes Mellitus and Alcohol Abuse with Cancer: Molecular Mechanisms and Clinical Significance

Diabetes mellitus (DM), one of the metabolic diseases which is characterized by sustained hyperglycemia, is a life-threatening disease. The global prevalence of DM is on the rise, mainly in low- and middle-income countries. Diabetes is a major cause of blindness, heart attacks, kidney failure, stroke, and lower limb amputation. Type 2 diabetes mellitus (T2DM) is a form of diabetes that is characterized by high blood sugar and insulin resistance. T2DM can be prevented or delayed by a healthy diet, regular physical activity, maintaining normal body weight, and avoiding alcohol and tobacco use. Ethanol and its metabolites can cause differentiation defects in stem cells and promote inflammatory injury and carcinogenesis in several tissues. Recent studies have suggested that diabetes can be treated, and its consequences can be avoided or delayed with proper management. DM has a greater risk for several cancers, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer. The incidence of cancer is significantly higher in patients with DM than in those without DM. In addition to DM, alcohol abuse is also a risk factor for many cancers. We present a review of the recent studies investigating the association of both DM and alcohol abuse with cancer incidence.

Metformin and Malignant Tumors: Not Over the Hill

Malignant tumors are a major cause of death, and their incidence is increasing worldwide. Although the survival rate for some cancers has improved, treatments for other malignant tumors are limited, and their mortality rate continues to increase. People with type 2 diabetes have a higher risk of malignant tumors and a higher mortality rate than those without diabetes. Metformin is a commonly used hypoglycemic drug. In recent years, a growing number of studies have indicated that metformin has antitumor effects and increases the sensitivity of malignant tumors to chemotherapy. However, the effect of metformin on different tumors is currently controversial, and the mechanism of metformin's antitumor action is not fully understood. Insights into the effect of metformin on malignant tumors and the possible mechanism may contribute to the development of antitumor drugs.