Metformin and LW6 impairs pancreatic cancer cells and reduces nuclear localization of YAP1

Radiation induced dermatitis by increasing triglyceride levels to induce autophagy and inhibit the PI3K/Akt/mTOR signaling pathway

BACKGROUND

Radiodermatitis (RD) is the primary acute adverse effect experienced by patients receiving radiotherapy (RT) for head and neck cancer (HNC). This study aimed to investigate the correlation between triglyceride (TG) levels and the severity of RD, as well as the underlying mechanisms involved.

METHODS

Data were collected from 248 patients with locally advanced HNC treated with intensity-modulated radiation therapy (IMRT). Clinical characteristics and blood profiles prior to RT were collected. After RT, RD severity was assessed. A binary logistic regression analysis was used to determine risk factors. Mouse models of RD were established by administering radiating at a dose of 9 Gy over two consecutive days. TG levels in the mice and cells were quantified using an automatic biochemical analyzer and a TG assay kit, respectively. Cell viability was detected by the Cell Counting Kit-8 (CCK-8) assay, while apoptotic cell percentages were measured via flow cytometry. Western blotting assay was used to analyze the protein levels in the cells of interest.

RESULTS

The TG level was the sole independent risk factor for grade 3 or higher (grade 3+) RD. Radiation was found to increase the TG content in both mouse blood and skin cells. Skin cells with high TG contents presented more severe radiation-induced damage when the radiation dose administered was 9 Gy over two consecutive days. The administration of 200 µmol/L palmitic acid (PA) or 2 Gy radiation independently did not affect HaCaT cell proliferation or apoptosis rates. Their combination was shown to induce skin cell injury. Mechanistically, autophagy was excessively activated. Furthermore, the protein concentrations of phospho-PI3K, phospho-Akt, and phospho-mTOR were notably decreased.

CONCLUSIONS

TGs are crucially involved in the development of RD. Increased TG levels after radiation treatment suppress the PI3K/Akt/mTOR pathway, induce autophagy, and exacerbate RD.

Dictyostelium Differentiation-Inducing Factor 1 Promotes Glucose Uptake via Direct Inhibition of Mitochondrial Malate Dehydrogenase in Mouse 3T3-L1 Cells

Differentiation-inducing factor 1 (DIF-1), found in Dictyostelium discoideum, has antiproliferative and glucose-uptake-promoting activities in mammalian cells. DIF-1 is a potential lead for the development of antitumor and/or antiobesity/antidiabetes drugs, but the mechanisms underlying its actions have not been fully elucidated. In this study, we searched for target molecules of DIF-1 that mediate the actions of DIF-1 in mammalian cells by identifying DIF-1-binding proteins in human cervical cancer HeLa cells and mouse 3T3-L1 fibroblast cells using affinity chromatography and liquid chromatography-tandem mass spectrometry and found mitochondrial malate dehydrogenase (MDH2) to be a DIF-1-binding protein in both cell lines. Since DIF-1 has been shown to directly inhibit MDH2 activity, we compared the effects of DIF-1 and the MDH2 inhibitor LW6 on the growth of HeLa and 3T3-L1 cells and on glucose uptake in confluent 3T3-L1 cells in vitro. In both HeLa and 3T3-L1 cells, DIF-1 at 10-40 μM dose-dependently suppressed growth, whereas LW6 at 20 μM, but not at 2-10 μM, significantly suppressed growth in these cells. In confluent 3T3-L1 cells, DIF-1 at 10-40 μM significantly promoted glucose uptake, with the strongest effect at 20 μM DIF-1, whereas LW6 at 2-20 μM significantly promoted glucose uptake, with the strongest effect at 10 μM LW6. Western blot analyses showed that LW6 (10 μM) and DIF-1 (20 μM) phosphorylated and, thus, activated AMP kinase in 3T3-L1 cells. Our results suggest that MDH2 inhibition can suppress cell growth and promote glucose uptake in the cells, but appears to promote glucose uptake more strongly than it suppresses cell growth. Thus, DIF-1 may promote glucose uptake, at least in part, via direct inhibition of MDH2 and a subsequent activation of AMP kinase in 3T3-L1 cells.

Leveraging metformin to combat hepatocellular carcinoma: its therapeutic promise against hepatitis viral infections

Hepatocellular carcinoma (HCC) is categorized among the most common primary malignant liver cancer and a primary global cause of death from cancer. HCC tends to affect males 2-4 times more than females in many nations. The main factors that raise the incidence of HCC are chronic liver diseases, hepatotropic viruses like hepatitis B (HBV) and C (HCV), non-alcoholic fatty liver disease, exposure to toxins like aflatoxin, and non-alcoholic steatohepatitis (NASH). Among these, hepatitis B and C are the most prevalent causes of chronic hepatitis globally. Metformin, which is made from a naturally occurring compound called galegine, derived from the plant Galega officinalis (G. officinalis ), has been found to exhibit antitumor effects in a wide range of malignancies, including HCC. In fact, compared to patients on sulphonylureas or insulin, studies have demonstrated that metformin treatment significantly lowers the risk of HCC in patients with chronic liver disease. This article will first describe the molecular mechanism of hepatitis B and C viruses in the development of HCC. Then, we will provide detailed explanations about metformin, followed by a discussion of the association between metformin and hepatocellular carcinoma caused by the viruses mentioned above.

Cell membrane-camouflaged bufalin targets NOD2 and overcomes multidrug resistance in pancreatic cancer

AIMS

Multidrug resistance in pancreatic cancer poses a significant challenge in clinical treatment. Bufalin (BA), a compound found in secretions from the glands of toads, may help overcome this problem. However, severe cardiotoxicity thus far has hindered its clinical application. Hence, the present study aimed to develop a cell membrane-camouflaged and BA-loaded polylactic-co-glycolic acid nanoparticle (CBAP) and assess its potential to counter chemoresistance in pancreatic cancer.

METHODS

The toxicity of CBAP was evaluated by electrocardiogram, body weight, distress score, and nesting behavior of mice. In addition, the anticarcinoma activity and underlying mechanism were investigated both in vitro and in vivo.

RESULTS

CBAP significantly mitigated BA-mediated acute cardiotoxicity and enhanced the sensitivity of pancreatic cancer to several clinical drugs, such as gemcitabine, 5-fluorouracil, and FOLFIRINOX. Mechanistically, CBAP directly bound to nucleotide-binding and oligomerization domain containing protein 2 (NOD2) and inhibited the expression of nuclear factor kappa-light-chain-enhancer of activated B cells. This inhibits the expression of ATP-binding cassette transporters, which are responsible for chemoresistance in cancer cells.

CONCLUSIONS

Our findings indicate that CBAP directly inhibits NOD2. Combining CBAP with standard-of-care chemotherapeutics represents a safe and efficient strategy for the treatment of pancreatic cancer.

HIF-1α Expression Increases Preoperative Concurrent Chemoradiotherapy Resistance in Hyperglycemic Rectal Cancer

Purpose: Preoperative concurrent chemoradiotherapy (CCRT) is the standard treatment for locally advanced rectal cancer patients. However, the poor therapeutic efficacy of CCRT was found in rectal cancer patients with hyperglycemia. This study investigated how hyperglycemia affects radiochemotherapy resistance in rectal cancer. Methods and Materials: We analyzed the correlation between prognosis indexes with hypoxia-inducible factor-1 alpha (HIF-1α) in rectal cancer patients with preoperative CCRT. In vitro, we investigated the effect of different concentrated glucose of environments on the radiation tolerance of rectal cancers. Further, we analyzed the combined HIF-1α inhibitor with radiation therapy in hyperglycemic rectal cancers. Results: The prognosis indexes of euglycemic or hyperglycemic rectal cancer patients after receiving CCRT treatment were investigated. The hyperglycemic rectal cancer patients (n = 13, glycosylated hemoglobin, HbA1c > 6.5%) had poorer prognosis indexes. In addition, a positive correlation was observed between HIF-1α expression and HbA1c levels (p = 0.046). Therefore, it is very important to clarify the relationship between HIF-1α and poor response in patients with hyperglycemia receiving pre-operative CCRT. Under a high glucose environment, rectal cancer cells express higher levels of glucose transport 1 (GLUT1), O-GlcNAc transferase (OGT), and HIF-1α, suggesting that the high glucose environment might stimulate HIF-1α expression through the GLUT1-OGT-HIF-1α pathway promoting tolerance to Fluorouracil (5-FU) and radiation. In the hyperglycemic rectal cancer animal model, rectal cancer cells confirmed that radiation exposure reduces apoptosis by overexpressing HIF-1α. Combining HIF-1α inhibitors was able to reverse radioresistance in a high glucose environment. Lower HIF-1α levels increased DNA damage in tumors leading to apoptosis. Conclusions: The findings here show that hyperglycemia induces the expression of GLUT1, OGT, and HIF-1α to cause CCRT tolerance in rectal cancer and suggest that combining HIF-1α inhibitors could reverse radioresistance in a high glucose environment. HIF-1α inhibitors may be useful for development as CCRT sensitizers in patients with hyperglycemic rectal cancer.

Development of a Transcription Factor-Based Prognostic Model for Predicting the Immune Status and Outcome in Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma (PAAD) is the most common primary malignancy of the pancreas. Growing studies indicate that transcription factors (TFs) are abnormally expressed in PAAD. We, therefore, aimed to evaluate the effect of TFs in PAAD and develop a TF-based prognostic signature for the patients. The expression of the TFs and the clinical characteristics were obtained from TCGA datasets. The levels of the TFs were evaluated in PAAD tissues or nontumor tissues. Kyoto Encyclopedia of Genes and Genomes (KEGG) was used to determine the potential function of the dysregulated TFs. To create a prognostic signature, we used univariate and multivariate Cox regression. In addition, the relationship between risk score and tumor microenvironment was analyzed. In this study, we observed 19 increased and 10 decreased TFs in PAAD tissues. KEGG assays indicated that dysregulated TFs were involved in transcriptional misregulation in cancer. Multivariate Cox analysis identified two prognostic factors, Zinc finger protein 488 and BCL11A; and we developed a risk score model by these two factors. The Kaplan-Meier estimator suggested that patients with high risk exhibited a shorter overall survival than those with low risk. The receiver operating characteristic curve proved that the accuracy of this prognostic signature was 0.686 in predicting the 5-year survival. In addition, we observed that the high score was distinctly related to advanced tumor stage and immune infiltrates. Taken together, we developed a novel TF-related model which could be applied as a potential prognostic tool for PAAD and may guide the choice of immunotherapies.

Novel sequential therapy with metformin enhances the effects of cisplatin in testicular germ cell tumours via YAP1 signalling

Background

Testicular germ cell tumours (TGCTs) are the most commonly diagnosed malignancy in young men. Although cisplatin has been shown to be effective to treat TGCT patients, long-term follow-up has shown that TGCT survivors who accepted cisplatin treatment suffered from a greater number of adverse reactions than patients who underwent orchiectomy alone. As metformin has shown an anticancer effect in various cancers, we investigated whether metformin could enhance the effects of cisplatin to treat TGCTs.

Methods

The anticancer effects of different treatment strategies consisting of metformin and cisplatin in TCam-2 and NTERA-2 cells were assessed in vitro and in vivo. First, we used a colony formation assay, CCK-8 and MTT assays to explore the viability of TGCT cells. Flow cytometry was used to assess the cell cycle and apoptosis of TGCTs. Then, Western blotting was used to detect the protein expression of TGCTs cells after different treatments. In addition, a xenograft model was used to investigate the effects of the different treatments on the proliferation of TGCT cells. Immunohistochemistry assays were performed to analyse the expression of related proteins in the tissues from the xenograft model.

Results

Metformin inhibited the proliferation of TCam-2 and NTERA-2 cells by arresting them in G1 phase, while metformin did not induce apoptosis in TGCT cells. Compared with cisplatin monotherapy, the CCK-8, MTT assay and colony formation assay showed that sequential treatment with metformin and cisplatin produced enhanced anticancer effects. Further study showed that metformin blocked the cells in G1 phase by inducing phosphorylated YAP1 and reducing the expression of cyclin D1, CDK6, CDK4 and RB, which enhanced the chemosensitivity of cisplatin and activated the expression of cleaved caspase 3 in TGCTs.

Conclusions

Our study discovers the important role of YAP1 in TGCTs and reports a new treatment strategy that employs the sequential administration of metformin and cisplatin, which can reduce the required cisplatin dose and enhance the sensitivity of TGCT cells to cisplatin. Therefore, this sequential treatment strategy may facilitate the development of basic and clinical research for anticancer therapies to treat TGCTs.

Role of Yes-associated Protein-1 in Gastrointestinal Cancers and Hepatocellular Carcinoma

Yes-associated protein-1 (YAP1) is a potent transcriptional co-activator and functions as an important downstream effector of the Hippo signaling pathway, which is key to regulating cell proliferation, apoptosis, and organ growth. YAP1 has been implicated as an oncogene for various human cancers including gastrointestinal cancers and hepatocellular carcinoma (HCC). YAP1 promotes tumorigenesis and cancer progression by multiple mechanisms, such as by promoting malignant phenotypes, expanding cancer stem cells, and inducing epithelial-mesenchymal transition. YAP1 overexpression or its activated forms are associated with advanced pathological grades and poor prognosis of cancer, and therefore targeting YAP1 may open a fertile avenue for cancer therapy. In this review, we summarize the recent evidence regarding the role of YAP1 in the carcinogenesis of gastrointestinal cancers and HCC.

Gene Regulation Network of Prognostic Biomarker YAP1 in Human Cancers: An Integrated Bioinformatics Study

Background: Yes-associated protein 1 (YAP1) is the main downstream effector of the Hippo signaling pathway, which is involved in tumorigenesis. This study aimed to comprehensively understand the prognostic performances of YAP1 expression and its potential mechanism in pan-cancers by mining databases.

Methods: The YAP1 expression was evaluated by the Oncomine database and GEPIA tool. The clinical significance of YAP1 expression was analyzed by the UALCAN, GEPIA, and DriverDBv3 database. Then, the co-expressed genes with YAP1 were screened by the LinkedOmics, and annotated by the Metascape and DAVID database. Additionally, by the MitoMiner 4.0 v tool, the YAP1 co-expressed genes were screened to obtain the YAP1-associated mitochondrial genes that were further enriched by DAVID and analyzed by MCODE for the hub genes.

Results: YAP1 was differentially expressed in human cancers. Higher YAP1 expression was significantly associated with poorer overall survival and disease-free survival in adrenocortical carcinoma (ACC), brain Lower Grade Glioma (LGG), and pancreatic adenocarcinoma (PAAD). The LinkedOmics analysis revealed 923 co-expressed genes with YAP1 in adrenocortical carcinoma, LGG and PAAD. The 923 genes mainly participated in mitochondrial functions including mitochondrial gene expression and mitochondrial respiratory chain complex I assembly. Of the 923 genes, 112 mitochondrial genes were identified by MitoMiner 4.0 v and significantly enriched in oxidative phosphorylation. The MCODE analysis identified three hub genes including CHCHD1, IDH3G and NDUFAF5.

Conclusion: Our findings showed that the YAP1 overexpression could be a biomarker for poor prognosis in ACC, LGG and PAAD. Specifically, the YAP1 co-expression genes were mainly involved in the regulation of mitochondrial function especially in oxidative phosphorylation. Thus, our findings provided evidence of the carcinogenesis of YAP1 in human cancers and new insights into the mechanisms underlying the role of YAP1 in mitochondrial dysregulation.

Drug Repurposing in Oncology: Current Evidence and Future Direction

BACKGROUND

Drug repurposing, the application of known drugs and compounds with a primary non-oncology purpose, might be an attractive strategy to offer more effective treatment options to cancer patients at a low cost and reduced time.

METHODS

This review described a total of 10 kinds of non-oncological drugs from more than 100 mechanical studies as well as evidence from population-based studies. The future direction of repurposed drug screening is discussed by using patient-derived tumor organoids.

RESULTS

Many old drugs showed previously unknown effects or off-target effects and can be intelligently applied for cancer chemoprevention and therapy. The identification of repurposed drugs needs to combine evidence from mechanical studies and population-based studies. Due to the heterogeneity of cancer, patient-derived tumor organoids can be used to screen the non-oncological drugs in vitro.

CONCLUSION

These identified old drugs could be repurposed in oncology and might be added as adjuvants and finally benefit patients with cancers.

Metformin Induces Autophagy via the AMPK-mTOR Signaling Pathway in Human Hepatocellular Carcinoma Cells

Background

Metformin may exert the anticancer effect on multiple types of cancers and some potential mechanisms have been suggested. Our study was designed to determine the effect of metformin on the cell autophagy and autophagic flux via the AMPK-mTOR signaling pathway in human hepatocellular carcinoma (HCC) cells.

Methods

MHCC97H and HepG2 cell lines were cultured and treated without and with metformin at various concentrations (2, 5, 10 and 20 mM) for 48 h. Then, 10 mM was determined as the optimal concentration and the HCC cells were treated with metformin for 12, 24, 48, and 72 h. MTT assay was used to assess the cell viability and Western blotting was used to determine the expression of proteins (LC3-II, p62, phospho-AMPKα, phospho-mTOR, mTOR, phospho-p70 S6 Kinase, p70 S6 Kinase, PARP1, Caspase-9 and Caspase-3). Autophagy inhibitor 3-methyladenine, EGFP-LC3 and mCherry-GFP-LC3B plasmid transfection were used for further study.

Results

Metformin inhibited significantly the viability of MHCC97H and HepG2 cells in a dose- and time-dependent manner. For the apoptotic properties, activation of Caspase-9 and Caspase-3 and PARP cleavage were not observed after treatment with metformin. MHCC97H cells were transfected with a EGFP-LC3 plasmid and treatment with metformin could lead to the increased level of LC3-II and decreased level of p62. In metformin-induced autophagy, AMPK expression was activated, and the phosphorylation levels of mTOR and p70 S6 Kinase were inhibited. Metformin treatment and mCherry-GFP-LC3B plasmid transfection showed that metformin could induce the autophagic flux. 3-Methyladenine (3-MA) partly abolished this effect.

Conclusion

Metformin could induce the autophagy, autophagic flux, and activate the AMPK-mTOR signaling pathway in human HCC cells.