Metformin depresses overactivated Notch1/Hes1 signaling in colorectal cancer patients with type 2 diabetes mellitus

Development and validation of a radiogenomics model to predict axillary lymph node metastasis in breast cancer integrating MRI with transcriptome data: A multicohort study

Introduction

To develop and validate a radiogenomics model for predicting axillary lymph node metastasis (ALNM) in breast cancer compared to a genomics and radiomics model.

Methods

This retrospective study integrated transcriptomic data from The Cancer Genome Atlas with matched MRI data from The Cancer Imaging Archive for the same set of 111 patients with breast cancer, which were used as the training and testing groups. Fifteen patients from one hospital were enrolled as the external validation group. Radiomics features were extracted from dynamic contrast-enhanced (DCE)-MRI of breast cancer, and genomics features were derived from differentially expressed gene analysis of transcriptome data. Boruta was used for genomics and radiomics data dimension reduction and feature selection. Logistic regression was applied to develop genomics, radiomics, and radiogenomics models to predict ALNM. The performance of the three models was assessed by receiver operating characteristic curves and compared by the Delong test.

Results

The genomics model was established by nine genomics features, and the radiomics model was established by three radiomics features. The two models showed good discrimination performance in predicting ALNM in breast cancer, with areas under the curves (AUCs) of 0.80, 0.67, and 0.52 for the genomics model and 0.72, 0.68, and 0.71 for the radiomics model in the training, testing and external validation groups, respectively. The radiogenomics model integrated with five genomics features and three radiomics features had a better performance, with AUCs of 0.84, 0.75, and 0.82 in the three groups, respectively, which was higher than the AUC of the radiomics model in the training group and the genomics model in the external validation group (both P < 0.05).

Conclusion

The radiogenomics model combining radiomics features and genomics features improved the performance to predict ALNM in breast cancer.

Low-Dose Metformin Treatment Reduces In Vitro Growth of the LL/2 Non-small Cell Lung Cancer Cell Line

Lung cancer maintains a relatively small survival rate (~19%) over a 5-year period and up to 80-85% of all lung cancer diagnoses are Non-Small Cell Lung Cancer (NSCLC). To determine whether metformin reduces non-small cell lung cancer (NSCLC) LL/2 cell growth, cells were grown in vitro and treated with metformin for 48 h. qPCR was used to assess genes related to cell cycle regulation and pro-apoptotic markers, namely Cyclin D, CDK4, p27, p21, and HES1. Treatment with 10 mM metformin significantly reduced HES1 expression (p = 0.011). Furthermore, 10 mM metformin treatment significantly decreased REDD1 (p = 0.0082) and increased p-mTOR Ser2448 (p = 0.003) protein expression. Control cells showed significant reductions in phosphorylated p53 protein expression (p = 0.0367), whereas metformin treated cells exhibited reduced total p53 protein expression (p = 0.0078). There were no significant reductions in AMPK, PKB/AKT, or STAT3. In addition, NSCLC cells were treated for 48 h. with 10 mM metformin, 4 µM gamma-secretase inhibitor (GSI), or the combination of metformin (10 mM) and GSI (4 µM) to determine the contribution of respective signaling pathways. Metformin treatment significantly reduced total nucleus expression of the proliferation maker Ki-67 with an above 65% reduction in Ki-67 expression between control and metformin-treated cells (p = 0.0021). GSI (4 µM) treatment significantly reduced Ki-67 expression by ~20% over 48 h (p = 0.0028). Combination treatment (10 mM metformin and 4 µM GSI) significantly reduced Ki-67 expression by more than 50% over 48 h (p = 0.0245). As such, direct administration of metformin (10 mM for 48 h) proved to be an effective pharmaceutical agent in reducing the proliferation of cultured non-small cell cancer cells. These intriguing in vitro results, therefore, support the further study of metformin in appropriate in vivo models as an anti-oncogenic agent and/or an adjunctive therapy.

Metformin and primary bone cancer risk in Taiwanese patients with type 2 diabetes mellitus

BACKGROUND

The effect of metformin on primary bone cancer risk has not been researched. This retrospective cohort study investigated the risk of primary bone cancer between metformin initiators and non-metformin initiators in patients with type 2 diabetes mellitus.

METHODS

A total of 673,532 patients with newly diagnosed type 2 diabetes mellitus and had been prescribed antidiabetic drugs for 2 or more times during 1999-2009 were enrolled from Taiwan's National Health Insurance. Metformin initiators and non-metformin initiators were defined according to the prescriptions of antidiabetic drugs within the initial 12 months. The patients were then followed up until December 31, 2011 for the incidence of primary bone cancer. Cox regression incorporated with the inverse probability of treatment-weighting using propensity scores was used to estimate hazard ratios in intention-to-treat and per-protocol analyses.

RESULTS

In the intention-to-treat analysis, the respective incidence rates were 10.56 and 12.90 per 100,000 person-years in 453,532 metformin initiators and 220,000 non-metformin initiators and the hazard ratio for initiators versus non-initiators was 0.830 (95% confidence interval 0.686-1.004, P-value = 0.0551). In the per-protocol analysis, the incidence rates were 7.58 and 11.77 per 100,000 person-years, respectively, and the hazard ratio was 0.615 (95% confidence interval 0.468-0.808, P-value = 0.0005). Subgroup analyses with regards to sex and age (<60 and ≥60 years) showed that the significantly lower risk associated with metformin use was only observed in men aged ≥60 years in the per-protocol analysis.

CONCLUSIONS

A significantly lower risk of primary bone cancer can be observed in patients with type 2 diabetes mellitus who adhere to metformin treatment. This benefit can only be observed in men aged ≥60 years.

Melatonin attenuates aortic oxidative stress injury and apoptosis in STZ-diabetes rats by Notch1/Hes1 pathway

Oxidative stress injury is an important link in the pathogenesis of diabetes, and reducing oxidative stress damage caused by long-term hyperglycemia is an important diabetic treatment strategy. Melatonin has been proved to be a free radical scavenger with strong antioxidant activity, and its protective effect on diabetes and the complications has been confirmed. However, the role and potential mechanism of melatonin in oxidative stress injury of diabetic aorta have not been reported. Besides, Notch signaling pathway plays an important role in vascular growth, differentiation, and apoptosis. We speculated that melatonin could improve oxidative stress injury of diabetic aorta through Notch1/Hes1 signaling pathway. STZ-induced diabetic rats and vascular smooth muscle cells (VSMCs) cultured with high glucose were treated with or without melatonin, melatonin receptor antagonist Luzindole, γ-secretase inhibitor DAPT respectively. We found that melatonin could improve the oxidative stress injury of diabetic aorta and reduce the apoptosis of VSMCs. Interestingly, melatonin could activate Notch1 signaling pathway, play an antioxidant role, and reduce the expression of apoptosis-related proteins. However, these protective effects could be largely eliminated by Luzindole or DAPT. We concluded that the repression of Notch1 signaling pathway would inhibit the repair of oxidative stress injury in diabetes. Melatonin could ameliorate oxidative stress injury and apoptosis of diabetic aorta by activating Notch1/Hes1 signaling pathway.

Correlation between Expression Profiles of Key Signaling Genes in Colorectal Cancer Samples from Type 2 Diabetic and Non-Diabetic Patients

Several lines of epidemiological and biochemical evidence support the association of type 2 diabetes mellitus (T2DM) and colorectal cancer (CRC). T2DM has been shown to impinge on the transcriptome of colon tumor cells, promoting their proliferation and invasion. In order to gain insight into diabetes-specific modulation of colon cancer signaling, we analyzed gene expression patterns of more than five hundred genes encoding signaling proteins on TaqMan OpenArray panels from colonoscopic colorectal tumor samples of type 2 diabetic and non-diabetic patients. In total, 48 transcripts were found to be differentially expressed in tumors of T2DM patients as compared to healthy colon samples. Enrichment analysis with the g:GOSt (Gene Ontology Statistics) functional profiling tool revealed that the underlying genes can be classified into five signaling pathways (in decreasing order of significance: Wnt (wingless-type)/β-catenin; Hippo; TNF (tumor necrosis factor); PI3K/Akt (phosphoinositide-3 kinase/protein kinase B), and platelet activation), implying that targeted downregulation of these signaling cascades might help combat CRC in diabetic patients. Transcript levels of some of the differentially expressed genes were also measured from surgically removed diabetic and non-diabetic CRC specimens by individual qPCR (quantitative real-time PCR) assays using the adjacent normal tissue mRNA levels as an internal control. The most significantly altered genes in diabetic tumor samples were largely different from those in non-diabetic ones, implying that T2DM profoundly alters the expression of signaling genes and presumably the biological characteristics of CRC.

Up-regulation of miR-139-5p protects diabetic mice from liver tissue damage and oxidative stress through inhibiting Notch signaling pathway

The occurrence and development of diabetes seriously threaten the health of patients. Therefore, the mechanism exploration of diabetes is of great significance for more effective control of this disease. In this study, we aimed to investigate the regulatory mechanism of miR-139-5p and Notch signaling pathway on liver damage and oxidative stress in diabetic mice. The mouse model of diabetes was established, and the mice were divided into normal group, model group, negative control (NC) group, miR-139-5p mimic group, miR-139-5p inhibitor group, DAPT group, and miR-139-5p inhibitor + DAPT group. The mRNA expressions of miR-139-5p, Notch1, Jagged1, and NICD1, and the protein expressions of Notch1, Jagged1, and NICD1 were detected. In addition, HepG2 cells were cultured for high glucose induction, and cell cycle distribution and apoptosis were detected by flow cytometry. The results showed that the body weights of mice in the model, NC, miR-139-5p mimic, miR-139-5p inhibitor, DAPT, and miR-139-5p inhibitor + DAPT groups were all lower than that in the normal group. Co-localization of miR-139-5p and Notch1 was observed in the fluorescence in situ hybridization assay, and miR-139-5p was found to negatively regulate Notch1. Furthermore, reduced blood glucose level and inhibited liver oxidative stress were observed in mice with miR-139-5p overexpression or DAPT treatment. DAPT treatment reversed the increase of blood glucose level and oxidative stress injury caused by miR-139-5p silencing. In conclusion, up-regulation of miR-139-5p expression can protect liver tissue from oxidative stress injury in diabetic mice, and its mechanism may be related to the inhibition of Notch signaling pathway.

Repurposed Biguanide Drugs in Glioblastoma Exert Antiproliferative Effects via the Inhibition of Intracellular Chloride Channel 1 Activity

The lack of in-depth knowledge about the molecular determinants of glioblastoma (GBM) occurrence and progression, combined with few effective and BBB crossing-targeted compounds represents a major challenge for the discovery of novel and efficacious drugs for GBM. Among relevant molecular factors controlling the aggressive behavior of GBM, chloride intracellular channel 1 (CLIC1) represents an emerging prognostic and predictive biomarker, as well as a promising therapeutic target. CLIC1 is a metamorphic protein, co-existing as both soluble cytoplasmic and membrane-associated conformers, with the latter acting as chloride selective ion channel. CLIC1 is involved in several physiological cell functions and its abnormal expression triggers tumor development, favoring tumor cell proliferation, invasion, and metastasis. CLIC1 overexpression is associated with aggressive features of various human solid tumors, including GBM, in which its expression level is correlated with poor prognosis. Moreover, increasing evidence shows that modification of microglia ion channel activity, and CLIC1 in particular, contributes to the development of different neuropathological states and brain tumors. Intriguingly, CLIC1 is constitutively active within cancer stem cells (CSCs), while it seems less relevant for the survival of non-CSC GBM subpopulations and for normal cells. CSCs represent GBM development and progression driving force, being endowed with stem cell-like properties (self-renewal and differentiation), ability to survive therapies, to expand and differentiate, causing tumor recurrence. Downregulation of CLIC1 results in drastic inhibition of GBM CSC proliferation in vitro and in vivo, making the control of the activity this of channel a possible innovative pharmacological target. Recently, drugs belonging to the biguanide class (including metformin) were reported to selectively inhibit CLIC1 activity in CSCs, impairing their viability and invasiveness, but sparing normal stem cells, thus representing potential novel antitumor drugs with a safe toxicological profile. On these premises, we review the most recent insights into the biological role of CLIC1 as a potential selective pharmacological target in GBM. Moreover, we examine old and new drugs able to functionally target CLIC1 activity, discussing the challenges and potential development of CLIC1-targeted therapies.

High glucose induces epithelial-mesenchymal transition and results in the migration and invasion of colorectal cancer cells

Diabetes mellitus (DM) is associated with an increased risk of colorectal cancer (CRC). Hyperglycemia, a chronic abnormality in diabetes, is an independent predictor of cancer-associated mortality in CRC. However, the underlying biological mechanism of hyperglycemia in CRC cells is largely unknown. In the present study, HCT-116 and HT-29 cell proliferation, apoptosis, migration and invasion were assessed. In addition, the expression of epithelial (E)-cadherin, vimentin and high-mobility group A protein 2 (HMGA2) were assessed using western blotting. The results demonstrated that high glucose (HG; 30 mmol/l) caused CRC cells to lose their epithelial morphology, with a decrease in E-cadherin and an increase in vimentin, suggesting epithelial-mesenchymal transition (EMT). Furthermore, HG significantly enhanced the cell migration and invasion of CRC cells and the expression of HMGA2. Transfection with HMGA2 small interfering RNA reversed the HG-induced changes to CRC cells. In addition, HG promoted CRC cell proliferation and suppressed apoptosis. The results of the present study suggest that hyperglycemia promotes EMT, proliferation, migration and invasion in CRC cells and may provide novel insights into the link between HG and CRC.