Metformin restores crizotinib sensitivity in crizotinib-resistant human lung cancer cells through inhibition of IGF1-R signaling pathway

Mechanisms of Resistance to ALK Inhibitors and Corresponding Treatment Strategies in Lung Cancer

Lung cancer continues to be a leading cause of cancer-related mortality and morbidity worldwide. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene accounts for approximately 3%-5% of gene mutation types. Targeted therapies for ALK mutations have made significant advancements in recent decades, enabling a considerable number of patients to achieve the goal of five-year survival benefits. However, overcoming the drug resistance that arises with current ALK tyrosine kinase inhibitors (TKIs) remain a major challenge in ALK-targeted therapies. In this review, we briefly discuss the primary and secondary mechanisms of resistance to ALK-TKIs, and explore treatment strategies based on progressive resistance models. Meanwhile, novel drugs and combination therapies are being actively researched and developed to address these challenges. The aim is to offer new insights into the mechanisms of resistance and the corresponding treatment strategies to ALK inhibitors.

Anti-EGFR therapy can overcome acquired resistance to the third-generation ALK-tyrosine kinase inhibitor lorlatinib mediated by activation of EGFR

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality. Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are standard treatments for EML4-ALK-positive NSCLC, but resistance to these agents remains a challenge. This study aimed to determine the mechanisms of acquired resistance to the third-generation ALK-TKI lorlatinib. Lorlatinib-resistant cell lines were established by prolonged exposure to a high concentration of lorlatinib. Activation of epidermal growth factor receptor (EGFR) caused by a decrease in endocytosis and degradation of protein was demonstrated to play an essential role in acquired resistance to lorlatinib. The interaction between the EGFR and ALK was investigated to identify binding sites and conformational changes in ALK. We performed high-throughput compound screening using a small-molecule drugs library comprising 510 antitumor agents in an effort to discover small-molecule compounds that target EGFR in lorlatinib-resistant cells. Combination treatment with ALK-TKI and anti-EGFR agents suppressed acquired resistance to ALK-TKIs caused by activation of EGFR in vitro and in vivo, suggesting that the combination of lorlatinib and an anti-EGFR agent could be effective in patients with lorlatinib-resistant NSCLC. This research provides insights into the mechanism of resistance to lorlatinib and suggests that it can be overcome by anti-EGFR treatment, offering a promising approach for treating resistance to lorlatinib mediated by EGFR activation in patients with ALK-positive NSCLC.

Metformin and glioma: Targeting metabolic dysregulation for enhanced therapeutic outcomes

Glioma, a highly aggressive form of brain cancer, continues to pose significant therapeutic challenges in the field of medicine. Its invasive nature and resistance to traditional treatments make it particularly difficult to combat. This review examines the potential of metformin, a commonly prescribed antidiabetic medication, as a promising new treatment option for glioma. The potential of metformin to target crucial metabolic pathways in cancer cells presents an encouraging approach to improve therapeutic outcomes. The review explores the complexities of metabolic reprogramming in glioma and metformin's role in inhibiting these metabolic pathways. Preclinical studies demonstrate metformin's efficacy in reducing tumor growth and enhancing the sensitivity of glioma cells to chemotherapy and radiotherapy. Furthermore, clinical studies highlight metformin's potential in improving progression-free survival and overall survival rates in glioma patients. The review also addresses the synergistic effects of combining metformin with other therapeutic agents, such as temozolomide and radiotherapy, to overcome drug resistance and improve treatment efficacy. Despite the promising findings, the review acknowledges the need for further clinical trials to establish optimal dosing regimens, understand the molecular mechanisms underlying metformin's antitumor effects, and identify patient populations that would benefit the most from metformin-based therapies. Additionally, the potential side effects and the long-term impact of metformin on Glioma patients require careful evaluation. In conclusion, this review underscores the potential of metformin as a repurposed drug in glioma treatment, emphasizing its multifaceted role in targeting metabolic dysregulation. Metformin holds promise as part of a combination therapy approach to improve the therapeutic landscape of glioma and offers hope for better patient outcomes.

Metformin: A Dual-Role Player in Cancer Treatment and Prevention

Cancer continues to pose a significant global health challenge, as evidenced by the increasing incidence rates and high mortality rates, despite the advancements made in chemotherapy. The emergence of chemoresistance further complicates the effectiveness of treatment. However, there is growing interest in the potential of metformin, a commonly prescribed drug for type 2 diabetes mellitus (T2DM), as an adjuvant chemotherapy agent in cancer treatment. Although the precise mechanism of action of metformin in cancer therapy is not fully understood, it has been found to have pleiotropic effects, including the modulation of metabolic pathways, reduction in inflammation, and the regulation of cellular proliferation. This comprehensive review examines the anticancer properties of metformin, drawing insights from various studies conducted in vitro and in vivo, as well as from clinical trials and observational research. This review discusses the mechanisms of action involving both insulin-dependent and independent pathways, shedding light on the potential of metformin as a therapeutic agent for different types of cancer. Despite promising findings, there are challenges that need to be addressed, such as conflicting outcomes in clinical trials, considerations regarding dosing, and the development of resistance. These challenges highlight the importance of further research to fully harness the therapeutic potential of metformin in cancer treatment. The aims of this review are to provide a contemporary understanding of the role of metformin in cancer therapy and identify areas for future exploration in the pursuit of effective anticancer strategies.

Crizotinib induces pulmonary toxicity by blocking autophagy flux in alveolar epithelial cells

Crizotinib is the first-line drug for advanced non-small cell lung cancer with the abnormal expression of anaplastic lymphoma kinase gene. Severe, life-threatening, or fatal interstitial lung disease/pneumonia has been reported in patients treated with crizotinib. The clinical benefit of crizotinib is limited by its pulmonary toxicity, but the underlying mechanisms have not been adequately studied, and protective strategies are relatively scarce. Here, we established an in vivo mouse model in which crizotinib was continuously administered to C57BL/6 at 100 mg/kg/day for 6 weeks and verified that crizotinib induced interstitial lung disease in vivo, which was consistent with the clinical observations. We further treated BEAS-2B and TC-1 cells, the alveolar epithelial cell lines, with crizotinib and found the increased apoptosis rate. We proved that crizotinib-blocked autophagic flux caused apoptosis of the alveolar epithelial cells and then promoted the recruitment of immune cells, suggesting that limited autophagy activity was the key reason for pulmonary injury and inflammation caused by crizotinib. Subsequently, we found that metformin could reduce the macrophage recruitment and pulmonary fibrosis by recovering the autophagy flux, thereby ameliorating impaired lung function caused by crizotinib. In conclusion, our study revealed the mechanism of crizotinib-induced apoptosis of alveolar epithelial cells and activation of inflammation during the onset of pulmonary toxicity and provided a promising therapeutic strategy for the treatment of crizotinib-induced pulmonary toxicity.

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.

Impact of metformin on tyrosine kinase inhibitor response in chronic myeloid leukemia

Objective

Oral tyrosine kinase inhibitors (TKIs) are first line therapy for chronic myeloid leukemia (CML). A complete cytogenetic response (CCyR) correlates with increased overall survival, however only 66%–88% of patients achieve CCyR after one year of TKI treatment. Because TKI therapy alone cannot eliminate CML stem cells, strategies aimed at achieving faster and deeper responses are needed to improve long-term survival. Metformin is a widely prescribed glucose-lowering agent for patients with diabetes and in preclinical studies, has been shown to suppress cell viability, induce apoptosis, and downregulate the mTORC1 signaling pathway in imatinib resistant CML cell lines (K562R). This study aims to investigate the utility of metformin added to TKI therapy in patients with CML.

Data Sources

An observational study at an academic medical center (Salt Lake City, UT) was performed for adults with newly diagnosed, chronic-phase CML to evaluate attainment of CCyR from TKI therapy with or without concomitant metformin use. Descriptive analyses were used to describe baseline characteristics and attainment of response to TKI therapy.

Data Summary

Fifty-nine patients were evaluated. One hundred percent (5 of 5) in the metformin group and 73.6% (39 of 54) in the non-metformin group achieved CCyR. Approximately 20% of patients in both groups relapsed (defined by a loss of CCyR during study) after a median 34.5 months of follow-up.

Conclusions

Future research is warranted to validate these findings and determine the utility of metformin added to TKI therapy.

Experimental Determination of Cancer Drug Targets with Independent Mechanisms of Resistance

Mathematical modelling of tumour mutation dynamics has suggested that cancer drug targets that have different resistance mechanisms should be good candidates for combination treatment. This is because the development of mutations that cause resistance to all drugs at once should arise relatively infrequently. However, it is difficult to identify drug targets fulfilling this requirement for particular cancers. Here we present four experimental criteria that we argue are necessary (but not sufficient) conditions that drug combinations should meet in order to be considered for combination drug treatment aimed at delaying or overcoming cancer drug resistance. We present the results of our own experiments - guided by these criteria - using anaplastic lymphoma kinase mutated lung cancer cells. Each set of experiments demonstrate results for different drug combinations. We conclude that the combination of ALK and MEK inhibitors come closest to meeting all our criteria.

BX-795 inhibits neuroblastoma growth and enhances sensitivity towards chemotherapy

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AKT overexpression correlates with poor prognosis in neuroblastoma patients.

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BX-795 inhibits PDK1 and abrogates the AKT signaling pathway activation.

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BX-795 demonstrates strong efficacy in neuroblastoma spheroid tumor model.

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Combination with BX-795 synergistically enhances doxorubicin antitumor activity.

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BX-795 synergistically sensitized ALK mutated neuroblastoma cell lines to crizotinib.

High-risk neuroblastoma (NB) represents a major clinical challenge in pediatric oncology due to relapse of metastatic, drug-resistant disease, and treatment-related toxicities. An analysis of 1235 primary NB patient dataset revealed significant increase in AKT1 and AKT2 gene expression with cancer stage progression. Additionally, Both AKT1 and AKT2 expression inversely correlate with poor overall survival of NB patients. AKT1 and AKT2 genes code for AKT that drive a major oncogenic cell signaling pathway known in many cancers, including NB. To inhibit AKT pathway, we repurposed an antiviral inhibitor BX-795 that inhibits PDK1, an upstream activator of AKT. BX-795 potently inhibits NB cell proliferation and colony growth in a dose-dependent manner. BX-795 significantly enhances apoptosis and blocks cell cycle progression at mitosis phase in NB. Additionally, BX-795 potently inhibits tumor formation and growth in a NB spheroid tumor model. We further tested dual therapeutic approaches by combining BX-795 with either doxorubicin or crizotinib and found synergistic and significant inhibition of NB growth, in contrast to either drug alone. Overall, our data demonstrate that BX-795 inhibits AKT pathway to inhibit NB growth, and combining BX-795 with current therapies is an effective and clinically tractable therapeutic approach for NB.

Hexokinases II-mediated glycolysis governs susceptibility to crizotinib in ALK-positive non-small cell lung cancer

Background

Activation of ALK leads to a high level of aerobic glycolysis related to crizotinib insensitivity in anaplastic lymphoma kinase‐positive non‐small cell lung cancer (ALK⁺ NSCLC). The strategy and mechanism of glycolysis inhibition in sensitizing ALK⁺ NSCLC cells to crizotinib requires further investigation.

Methods

The levels of glycolysis in H3122 and H2228 cells were evaluated through detection of glucose consumption and lactate production. MTT assay was used to explore the effects of glycolytic inhibitors on crizotinib sensitivity, and the potential mechanism of action were detected by colony formation, Ki67 incorporation assay, transwell assay, small interfering RNA technology and western blot analysis.

Results

ALK⁺ NSCLC cells exhibited significantly higher levels of glycolysis compared to ALK⁻ NSCLC cells. Long‐term exposure to crizotinib could decrease the sensitivity of ALK⁺ NSCLC cells to crizotinib via increasing the levels of glycolysis related to hexokinases II (HK2). Crizotinib in combination with glycolysis inhibitor 2‐deoxy‐D‐glucose (2DG) synergistically inhibited proliferation, glycolysis, colony formation and invasion ability of ALK⁺ NSCLC cells. 2DG sensitization crizotinib might be associated with the inhibition of HK2‐mediated glycolysis and P‐ALK/AKT/mTOR signaling pathway in H3122 and H2228 cells.

Conclusions

These results indicate that HK2‐mediated glycolysis plays a crucial role in the increased tolerance of ALK⁺ NSCLC cells to crizotinib. 2DG may sensitize ALK⁺ NSCLC to crizotinib via suppression of HK2‐mediated glycolysis and the AKT/mTOR signaling pathway.

Clinical Predictors of Prolonged Hospital Stay in Patients with Myasthenia Gravis: A Study Using Machine Learning Algorithms

Myasthenia gravis (MG) is an autoimmune disorder that causes muscle weakness. Although the management is well established, some patients are refractory and require prolonged hospitalization. Our study is aimed to identify the important factors that predict the duration of hospitalization in patients with MG by using machine learning methods. A total of 21 factors were chosen for machine learning analyses. We retrospectively reviewed the data of patients with MG who were admitted to hospital. Five machine learning methods, including stochastic gradient boosting (SGB), least absolute shrinkage and selection operator (Lasso), ridge regression (Ridge), eXtreme gradient boosting (XGboost), and gradient boosting with categorical features support (Catboost), were used to construct models for identify the important factors affecting the duration of hospital stay. A total of 232 data points of 204 hospitalized MG patients admitted were enrolled into the study. The MGFA classification, treatment of high-dose intravenous corticosteroid, age at admission, treatment with intravenous immunoglobulins, and thymoma were the top five significant variables affecting prolonged hospitalization. Our findings from machine learning will provide physicians with information to evaluate the potential risk of MG patients having prolonged hospital stay. The use of high-dose corticosteroids is associated with prolonged hospital stay and to be used cautiously in MG patients.

ALK-positive non-small cell lung cancer; potential combination drug treatments

Advances in chromosomally rearranged ALK positive non-small cell lung cancer have been dramatic in only the last few years. Survival times have improved dramatically due to the introduction of ever more efficacious ALK inhibitors. These improvements have been due largely to improvements in blood-brain barrier penetration and the breadth of ligand binding pocket mutations against which the drugs are effective. However, the advances maybe slow as compared to the frequency of cancers with compound resistance mutations are appearing, suggesting the need to develop multiple ALK inhibitors to target different compound mutations.Another research area that promises to provide further gains is the use of drug combinations, with an ALK inhibitor combined with a drug targeting a "second driver" to overcome resistance. In this review, the range of secondary targets for ALK+ lung cancer and the potential for their clinical success are reviewed.

Relationship between long non-coding RNA PCAT-1 expression and gefitinib resistance in non-small-cell lung cancer cells

BACKGROUND

Gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, has been used as first-line treatment for advanced non-small-cell lung cancer (NSCLC). However, during treatment, cancer cells often develop resistance to gefitinib, the mechanisms of which are not fully understood. This study was designed to elucidate the expression and role of long non-coding RNA (lncRNA)-PCAT-1, a potential biomarker for drug resistance and a therapeutic target for NSCLC, in gefitinib resistance in NSCLC cells.

METHODS

In this study, we verified differential PCAT-1 expression in NSCLC gefitinib-resistant tissues or cells. PCAT-1 knockdown, clone formation, Transwell, flow cytometry, and immunofluorescence assays were used to verify the correlation between PCAT-1 and gefitinib sensitivity. A nude mouse tumor-bearing model verified that PCAT-1 can reverse gefitinib resistance in vivo. Then, a PI3K/Akt agonist was used to verify the possible mechanism of PCAT-1 action.

RESULTS

PCAT-1 is highly expressed in gefitinib-resistant NSCLC tissues and cells. PCAT-1 knockdown enhanced gefitinib sensitivity and gefitinib-induced apoptosis in H1299/GR cells. PCAT-1 knockdown reduced tumor volume and weight, and reversed acquired gefitinib resistance in vivo. PCAT-1 knockdown inhibited AKT and GSK3 phosphorylation in H1299/GR cells. A PI3K/AKT agonist reversed PCAT-1 knockdown-mediated enhancement of gefitinib sensitivity in H1299/GR cells CONCLUSION: PCAT-1 knockdown improves sensitivity to gefitinib by inhibition of AKT and GSK3 phosphorylation in NSCLC. PCAT-1 is as potential target for improving the clinical efficacy of gefitinib.

Metformin impairs cisplatin resistance effects in A549 lung cancer cells through mTOR signaling and other metabolic pathways

Lung cancer is the leading cause of cancer‑associated death worldwide and exhibits intrinsic and acquired therapeutic resistance to cisplatin (CIS). The present study investigated the role of mTOR signaling and other signaling pathways after metformin (MET) treatment in control and cisplatin‑resistant A549 cells, mapping pathways and possible targets involved in CIS sensitivity. MTT, flow cytometry, clonogenic assay, western blotting, proteomic analysis using the Stable Isotope Labeling by Amino acids in Cell culture (SILAC) approach and reverse transcription‑quantitative PCR were performed. The results revealed that CIS treatment induced mTOR signaling pathway overactivation, and the mTOR status was restored by MET. MET and the mTOR inhibitor rapamycin (RAPA) decreased the viability in control and resistant cells, and decreased the cell size increase induced by CIS. In control cells, MET and RAPA decreased colony formation after 72 h and decreased IC₅₀ values, potentiating the effects of CIS. Proteomics analysis revealed important pathways regulated by MET, including transcription, RNA processing and IL‑12‑mediated signaling. In CIS‑resistant cells, MET regulated the apoptotic process, oxidative stress and G₂/M transition. Annexin 4 (ANXA4) and superoxide dismutase 2 (SOD2), involved in apoptosis and oxidative stress, respectively, were chosen to validate the SILAC analysis and may represent potential therapeutic targets for lung cancer treatment. In conclusion, the chemosensitizing and antiproliferative effects of MET were associated with mTOR signaling and with potential novel targets, such as ANXA4 and SOD2, in human lung cancer cells.

[Research Advance in Anti-lung Cancer Mechanism of Metformin]

二甲双胍作为治疗2型糖尿病的一线用药，安全性及有效性得到证实。近年来流行病学研究发现二甲双胍具有抑制肺癌细胞增殖及转移等特性，有望成为一种新的抗肺癌药物。肺癌是一种严重危害人类健康的疾病，其发病率和死亡率一直居所有恶性肿瘤之首，且预后差。近年来大量证据表明二甲双胍能降低肺癌等肿瘤的发病风险及死亡率，其机制主要包括激活单磷酸腺苷活化的蛋白激酶通路、改善高胰岛素血症及胰岛素抵抗、促进肺癌细胞凋亡、抑制相关炎症反应等。本文就二甲双胍对肺癌的研究做一综述。

The effect of metformin in EML4-ALK+ lung cancer alone and in combination with crizotinib in cell and rodent models

Cell based studies have suggested that the diabetes drug metformin may combine with the anaplastic lymphoma kinase receptor (ALK) inhibitor crizotinib to increase ALK positive lung cancer cell killing and overcome crizotinib resistance. We therefore tested metformin alone and in combination with crizotinib in vivo, by employing a xenograft mouse model of ALK positive lung cancer. We found that 14 days of daily oral metformin (100 mg/kg) alone had a moderate but statistically significant effect on tumour growth suppression, but in combination with crizotinib, produced no greater tumour suppression than crizotinib (25 mg/kg) alone. We also reassessed the effect of metformin on EML₄-ALK positive lung cancer (H3122) cell viability. Although metformin alone did have a moderate effect on cell viability (30% suppression) this was only at a clinically irrelevant concentration (5 mM) and there was no additive effect with cytotoxic concentrations of crizotinib. Moreover, metformin did not overcome crizotinib resistance in our resistant cells. Nevertheless, we were able to show that metformin induces a G1-cell cycle arrest and apoptosis alone and in combination with crizotinib. Also, consistent with earlier work, the addition of insulin-like growth factor-1 (IGF-1) to EML₄-ALK positive cancer cells reduced cell killing by crizotinib. We therefore hypothesised that the effect of metformin in vivo was not due to direct cytotoxicity on cancer cells, but by modulation of IGF-1 expression. We therefore measured levels of IGF-1 in plasma taken from mice treated with metformin, but found no difference between the drug treatment and control groups. We further hypothesised that the effect of metformin could be due to modulation of thrombospondin 1 (TSP-1), which metformin has been proposed to regulatein vivo, but again we found no difference between the experimental groups. Finally, we investigated the potential for liver and kidney toxicity, as well as CYP3A based interactions, from the combination of metformin with crizotinib.

Molecular mechanisms underlining the role of metformin as a therapeutic agent in lung cancer

BACKGROUND

Metformin, a first-line therapeutic for type 2 diabetes, has been studied for its potential use in cancer treatment following a number of epidemiological studies that have demonstrated reduced cancer incidence and mortality rates among patients treated with the drug. As yet, however, there remains significant uncertainty about the molecular mechanisms by which metformin exerts its anti-cancer effects. Herein, we summarize the evidence surrounding the anti-lung cancer effects of metformin.

CONCLUSIONS

Specifically, we explore protein targets of metformin, including AMPK, PP2A, IRF-1/YAP and HGF and we outline the proposed mechanisms of action for metformin in lung cancer, with particular attention given to apoptosis and autophagy. We also closely examine the synergistic activity of metformin with existing cancer treatment regimens, such as TKI's, platinum-based agents and immune therapeutics. In addition to considering preclinical and clinical studies, we also dissect and contextualize the limitations and inconsistencies of the current literature, especially those of epidemiological studies. Finally, we offer a potential trajectory for future research in this rapidly evolving area of basic and clinical oncology.

Activation of IGF-1R pathway and NPM-ALK G1269A mutation confer resistance to crizotinib treatment in NPM-ALK positive lymphoma

ALK-positive anaplastic large cell lymphoma (ALCL) represents a subset of non-Hodgkin's lymphoma that is treated with crizotinib, a dual ALK/MET inhibitor. Despite the remarkable initial response, ALCLs eventually develop resistance to crizotinib. ALK inhibitor resistance in tumors is a complex and heterogeneous process with multiple underlying mechanisms, including ALK gene amplification, ALK kinase domain mutation, and the activation of various bypass signaling pathways. To overcome resistance, multiple promising next-generation ALK kinase inhibitors and rational combinatorial strategies are being developed. To determine how cancers acquire resistance to ALK inhibitors, we established a model of acquired crizotinib resistance by exposing a highly sensitive NPM-ALK-positive ALCL cell line to increasing doses of crizotinib until resistance emerged. We found that the NPM-ALK mutation was selected under intermediate-concentration drug stress in resistant clones, accompanied by activation of the IGF-1R pathway. In the crizotinib-resistant ALCL cell model, the IGF-1R pathway was activated, and combined ALK/IGF-1R inhibition improved therapeutic efficacy. Furthermore, we also detected the NPM-ALK G1269A mutation, which had previously been demonstrated to result in decreased affinity for crizotinib, in the resistant cell model. Although crizotinib was ineffective against cells harboring the NPM-ALK G1269A mutation, five structurally different ALK inhibitors, alectinib, ceritinib, TAE684, ASP3026 and AP26113, maintained activity against the resistant cells. Thus, we have shown that second-generation ALK tyrosine kinase inhibitors or IGF-1R inhibitors are effective in treating crizotinib-resistant tumors.

Metformin reduces HGF-induced resistance to alectinib via the inhibition of Gab1

Alectinib is a second-generation anaplastic lymphoma kinase (ALK) inhibitor that has sufficient clinical efficacy and satisfactory safety in ALK-positive non-small cell lung cancer (NSCLC) patients with or without brain metastasis. Alectinib has now become an important drug in the first-line treatment of advanced ALK-positive NSCLC; however, resistance is almost inevitable. The increased expression of hepatocyte growth factor (HGF) and its physiological receptor tyrosine kinase MET have been shown to be linked to acquired resistance to various tyrosine kinase inhibitors (TKIs), and this phenomenon has been observed in some ALK-positive NSCLC tumour tissues. In this study, we found that HGF levels in the culture supernatant of an ALK-positive cell line tended to increase with time and could be further increased by alectinib in a time-dependent manner. Exogenous or endogenous HGF did not cause resistance to the ALK/MET double-targeted small molecule inhibitor crizotinib, but it was an important cause of alectinib resistance. Furthermore, Gab1 was a key effector in the HGF/MET signal transduction pathway that mediated alectinib resistance. The antidiabetic drug metformin combined with alectinib overcame alectinib resistance triggered by HGF/MET through disrupting the complex between MET and Gab1, thereby inhibiting Gab1 phosphorylation and the activation of downstream signal transduction pathways. These results suggest that metformin combined with alectinib may be useful for overcoming alectinib resistance induced by the activation of the HGF/MET signalling pathway and improving the efficacy of alectinib.

Metastasis manners and the underlying mechanisms of ALK and ROS1 rearrangement lung cancer and current possible therapeutic strategies

The rearrangements of anaplastic lymphoma kinase (ALK) and the c-ros oncogene 1 (ROS1) have both been important driving factors in non-small-cell lung cancer (NSCLC). They have already been defined in 3-5% of NSCLC patients. ALK and ROS1 rearrangements are associated with unique clinical and pathological features, especially patients are usually younger, with milder or never smoking history, and adenocarcinoma histology. Also, they have both been found to contribute to the metastasis of NSCLC by cell migration and invasion. It has recently been recognized that the brain can be considered as a primary site for metastasis in cancers with ALK or ROS1 rearrangements. The present review summarizes the current status of NSCLC metastasis and possible mechanisms based on available evidence, and then we list possible therapeutic strategies so that an increase in control of ALK and ROS1 rearrangement of NSCLC metastases by combination therapy can be translated in an increase in overall survival and prognosis.

Role of Metformin in the Treatment of Patients with Thyroid Nodules and Insulin Resistance: A Systematic Review and Meta-Analysis

BACKGROUND

Metformin is the most-prescribed oral medication to lower blood glucose worldwide. Some data suggest that metformin may have a role in the treatment of patients with thyroid nodules, but contrasting results are reported in different settings. This study explores and critically reevaluates the knowledge on this topic.

METHODS

A literature search identified 250 records. Studies evaluating the size of thyroid nodules before and after metformin treatment were included. Assessed outcomes were the size of thyroid nodules, thyrotropin (TSH) level, thyroid gland volume, and insulin resistance index (HOMA-IR). After screening and full-text assessment, five studies were included in the systematic review. Random-effects meta-analyses of the standardized mean difference (SMD) were performed for the four outcomes of interest. Heterogeneity was estimated using I², and the quality of evidence was assessed for each outcome using the Grading of Recommendations Assessment, Development, and Evaluation guidelines.

RESULTS

A total of 189 patients were included in the final analysis. After metformin treatment, a slight but significant reduction in thyroid nodule size was found in four studies, which included a total of 167 patients (SMD 0.46 [confidence interval (CI) 0.00-0.93]; p = 0.05). Similarly, in four studies reporting on a total of 146 patients, significant reductions in TSH level (SMD 0.30 [CI 0.07-0.53]; p = 0.01) and HOMA-IR level (SMD 0.90 [CI 0.12-1.67]; p = 0.02) were reported after treatment with metformin. In two studies, which included 114 patients, no change in thyroid gland volume was discovered after treatment with metformin (SMD 0.21 [CI -0.05 to 0.47]; p = 0.11). Quality of evidence was generally assessed as low or very low.

CONCLUSIONS

Metformin induces reductions in thyroid nodule size and TSH and HOMA-IR levels in patients with thyroid nodules and insulin resistance. In contrast, no change in thyroid gland volumes was found. Whether metformin treatment for thyroid nodules has clinical significance remains to be demonstrated.

Metformin enhances the radiosensitizing effect of cisplatin in non-small cell lung cancer cell lines with different cisplatin sensitivities

Cisplatin is an extensively used chemotherapeutic drug for lung cancer, but the development of resistance decreases its effectiveness in the treatments of non-small cell lung cancer (NSCLC). In this study, we examined the effects of metformin, a widely used antidiabetic drug, on cisplatin radiosensitization in NSCLC cell lines. Human NSCLC cell lines, A549 (cisplatin-resistant) and H460 (cisplatin-sensitive), were treated with metformin, cisplatin or a combination of both drugs before ionizing radiation. Cell proliferation, clonogenic assays, western blotting, cisplatin-DNA adduct formation and immunocytochemistry were used to characterize the treatments effects. Metformin increased the radiosensitivity of NSCLC cells. Metformin showed additive and over-additive effects in combination with cisplatin and the radiation response in the clonogenic assay in H460 and A549 cell lines (p = 0.018 for the interaction effect between cisplatin and metformin), respectively. At the molecular level, metformin led to a significant increase in cisplatin-DNA adduct formation compared with cisplatin alone (p < 0.01, ANOVA-F test). This was accompanied by a decreased expression of the excision repair cross-complementation 1 expression (ERCC1), a key enzyme in nucleotide excision repair pathway. Furthermore, compared with each treatment alone metformin in combination with cisplatin yielded the lowest level of radiation-induced Rad51 foci, an essential protein of homologous recombination repair. Ionizing radiation-induced γ-H2AX and 53BP1 foci persisted longer in both cell lines in the presence of metformin. Pharmacological inhibition of AMP-activated protein kinase (AMPK) demonstrated that metformin enhances the radiosensitizing effect of cisplatin through an AMPK-dependent pathway only in H460 but not in A549 cells. Our results suggest that metformin can enhance the effect of combined cisplatin and radiotherapy in NSCLC and can sensitize these cells to radiation that are not sensitized by cisplatin alone.

Metformin and tenovin-6 synergistically induces apoptosis through LKB1-independent SIRT1 down-regulation in non-small cell lung cancer cells

Sirtuin 1 (SIRT1) is known to play a role in a variety of tumorigenesis processes by deacetylating histone and non‐histone proteins; however, antitumour effects by suppressing SIRT1 activity in non‐small cell lung cancer (NSCLC) remain unclear. This study was designed to scrutinize clinicopathological significance of SIRT1 in NSCLC and investigate effects of metformin on SIRT1 inhibition. This study also evaluated new possibilities of drug combination using a SIRT1 inhibitor, tenovin‐6, in NSCLC cell lines. It was found that SIRT1 was overexpressed in 300 (62%) of 485 formalin‐fixed paraffin‐embedded NSCLC tissues. Its overexpression was significantly associated with reduced overall survival and poor recurrence‐free survival after adjusted for histology and pathologic stage. Thus, suppression of SIRT1 expression may be a reasonable therapeutic strategy for NSCLC. Metformin in combination with tenovin‐6 was found to be more effective in inhibiting cell growth than either agent alone in NSCLC cell lines with different liver kinase B1 (LKB1) status. In addition, metformin and tenovin‐6 synergistically suppressed SIRT1 expression in NSCLC cells regardless of LKB1 status. The marked reduction in SIRT1 expression by combination of metformin and tenovin‐6 increased acetylation of p53 at lysine 382 and enhanced p53 stability in LKB1‐deficient A549 cells. The combination suppressed SIRT1 promoter activity more effectively than either agent alone by up‐regulating hypermethylation in cancer 1 (HIC1) binding at SIRT1 promoter. Also, suppressed SIRT1 expression by the combination synergistically induced caspase‐3‐dependent apoptosis. The study concluded that metformin with tenovin‐6 may enhance antitumour effects through LKB1‐independent SIRT1 down‐regulation in NSCLC cells.

Association Between Metformin and Sulfonylurea Monotherapies and Cancer Incidence: A Real-World Cohort Study in Shanghai, China

INTRODUCTION

Previous studies have shown that patients with type 2 diabetes mellitus have an increased risk of cancer. The use of antidiabetic medication (ADM) may play an important role in the cancer development. The relationship between oral ADM and cancer incidence has not been investigated in type 2 diabetes mellitus patients in mainland China yet.

METHODS

A community-based diabetes cohort was extracted from the Shanghai Community Diabetes Management System database, which is a patient registry from general practices. The cohort included 2353 newly onset type 2 diabetes mellitus patients from 2006 to 2010 aged 35 years or more. Patients were grouped into nonusers of antidiabetic medication (n = 722), metformin monotherapy (n = 374), sulfonylurea monotherapy (n = 653), metformin and sulfonylurea combination therapy (n = 302), and other medication therapies (n = 302) on the basis of initial treatment type at registry entry. Cancer incidence was identified from the Shanghai Cancer Registry Organization. Comparisons between monotherapy and nonuser of medication were conducted using Cox proportional hazards models.

RESULTS

A total of 94 cancer cases were identified during 5 years median follow-up. Compared with nonusers, sulfonylurea monotherapy was associated with significantly lower risk of cancer [adjusted HR = 0.50 (95% CI 0.29-0.85)] whereas risk was 49% lower with metformin monotherapy [adjusted HR = 0.51 (95% CI 0.27-0.99)].

CONCLUSION

The real-world evidence suggested that the use of metformin or sulfonylurea was associated with lower risk of cancer incidence in a cohort of newly onset type 2 diabetes mellitus patients.

Metformin inhibits ovarian cancer growth and migration in vitro and in vivo by enhancing cisplatin cytotoxicity

The purpose of the current study was to investigate whether metformin can enhance the anti-cancer effect of cisplatin on epithelial ovarian cancer in vitro and in vivo. CCK-8 assays were performed to detect cell viability, and flow cytometry was performed to measure cell apoptosis rates. Transwell assays were used to detect the migration and invasion ability of ovarian cancer cells. Western blotting and qRT-PCR were performed to detect protein expression. Xenograft mouse models were constructed to clarify the treatment response in vivo. Metformin alone or cisplatin alone dose-dependently inhibited SKOV3 and Hey cell proliferation. The combination of these two drugs exerted a stronger inhibitory effect with a higher apoptosis rate than administration of either drug alone. Transwell assay results revealed that metformin promoted the inhibitory effect of cisplatin on ovarian cancer cell metastasis. Metformin and cisplatin co-treatment significantly inhibited N-cadherin and MMP-9 expression. The Western blotting results revealed that metformin and cisplatin co-treatment inhibited TGFβ1 expression and Smad2 and Smad3 phosphorylation. The in vivo study results were consistent with results from the in vitro study. Data from our study suggest that metformin enhanced the anti-tumour effect of cisplatin on epithelial ovarian cancer in vitro and in vivo, which provides more evidence supporting the use of metformin to treat epithelial ovarian cancer.

Repurposing old drugs in oncology: Opportunities with clinical and regulatory challenges ahead

WHAT IS KNOWN AND OBJECTIVE

In order to expedite the availability of drugs to treat cancers in a cost-effective manner, repurposing of old drugs for oncological indications is gathering momentum. Revolutionary advances in pharmacology and genomics have demonstrated many old drugs to have activity at novel antioncogenic pharmacological targets. We decided to investigate whether prospective studies support the promises of nonclinical and retrospective clinical studies on repurposing three old drugs, namely metformin, valproate and astemizole.

METHODS

We conducted an extensive literature search through PubMed to gather representative nonclinical and retrospective clinical studies that investigated the potential repurposing of these three drugs for oncological indications. We then searched for prospective studies aimed at confirming the promises of retrospective data.

RESULTS AND DISCUSSION

While evidence from nonclinical and retrospective clinical studies with these drugs appears highly promising, large scale prospective studies are either lacking or have failed to substantiate this promise. We provide a brief discussion of some of the challenges in repurposing. Principal challenges and obstacles relate to heterogeneity of cancers studied without considering their molecular signatures, trials with small sample size and short duration, failure consider issues of ethnicity of study population and effective antioncogenic doses of the drug studied.

WHAT IS NEW AND CONCLUSION

Well-designed prospective studies demonstrating efficacy are required for repurposing old drugs for oncology indications, just as they are for new chemical entities for any indication. Early and ongoing interactions with regulatory authorities are invaluable. We outline a tentative framework for a structured approach to repurposing old drugs for novel indications in oncology.

Combined treatment with metformin and gefitinib overcomes primary resistance to EGFR-TKIs with EGFR mutation via targeting IGF-1R signaling pathway

Aim

Although EGFR tyrosine kinase inhibitors (TKIs) have shown dramatic effects against sensitizing EGFR mutations in non-small cell lung cancer (NSCLC), ~20%–30% of NSCLC patients with EGFR-sensitive mutation exhibit intrinsic resistance to EGFR-TKIs. The purpose of the current study was to investigate the enhanced antitumor effect of metformin (Met), a biguanide drug, in combination with gefitinib (Gef) in primary resistant human lung cancer cells and the associated molecular mechanism.

Experimental design

H1975 cell line was treated with Met and/or Gef to examine the inhibition of cell growth and potential mechanism of action by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Ki67 incorporation assay, flow cytometry analysis, small interfering RNA technology, Western blot analysis and xenograft implantation.

Results

Insulin-like growth factor-1 receptor (IGF-1R) signaling pathway was markedly activated in EGFR-TKI primary resistant H1975 cells as compared to EGFR-TKI acquired resistance cells (PC-9GR, H1650-M3) and EGFR-TKI sensitivity cells (PC-9, HCC827). Inhibition of IGF-1R activity by AG-1024 (a small molecule of IGF-1R inhibitor), as well as downregulation of IGF-1R by siRNA, significantly enhanced the ability of Gef to suppress proliferation and induce apoptosis in H1975 cells via the inhibition of AKT activation and subsequent upregulation of Bcl-2-interacting mediator of cell death (BIM). Interestingly, the observation showed that Met combined with Gef treatment had similar tumor growth suppression effects in comparison with the addition of AG-1024 to therapy with Gef. A clear synergistic antiproliferative interaction between Met and Gef was observed with a combination index (CI) value of 0.65. Notably, IGF-1R silencing mediated by RNA interference (RNAi) attenuated anticancer effects of Met without obviously resensitizing H1975 cells to Gef. Finally, Met-based combinatorial therapy effectively blocked tumor growth in the xenograft with TKI primary resistant lung cancer cells.

Conclusion

Our findings demonstrated that Met combined with Gef would be a promising strategy to overcome EGFR-TKI primary resistance via suppressing IGF-1R signaling pathway in NSCLC.

Myasthenia gravis as a prognostic marker in patients with thymoma

Background

Thymoma is the most common mediastinal tumor, representing <1% of all cancers. It is usually associated with paraneoplastic disorders, mainly myasthenia gravis (MG). The aim of the present study was to describe patients with thymoma and the differences between those with MG and those without it.

Methods

A retrospective 10-year database of the patients with thymoma treated at a single cancer referral hospital (National Institute of Cancer, Mexico City), was analyzed.

Results

Sixty-four files from patients with thymoma were analyzed, 18 of them had MG. The symptoms that occurred most frequently in patients with MG were ptosis, diplopia, appendicular weakness, dysphonia and dysphagia. The most frequent Myasthenia Gravis Foundation of America (MGFA) stage was IIIb followed by stage I. Almost all the patients with MG had positive Acetylcholine Receptor antibodies (P<0.001), with not specified antibodies in four patients. The median overall survival showed a trend to be higher among the patients with MG, but there were no significant differences.

Conclusions

In patients with thymoma MG manifests with different clinical and autoimmune traits, but not survival differences. A larger multi-centric study should be encouraged to evaluate the prognostic implications of having MG in patients with thymoma.

Metformin for non-small cell lung cancer patients: Opportunities and pitfalls

Despite exciting advances of the anticancer armamentarium in the recent years, mortality of non-small cell lung cancer (NSCLC) remains high and novel treatments are requisite. Therapy intensification is explored with promising, but expensive and potentially toxic new compounds. Repositioning already existing drugs for cancer treatment could save money and improve patient outcomes in specific contexts. Observational data suggest that use of the standard antidiabetic agent metformin decreases lung cancer incidence and mortality. Several basic researches have shown various anticancer effects of metformin, acting both on the glycolytic metabolism and on the tumoral immune microenvironment. Synergistic actions of metformin with antitumoral agents in preclinical NSCLC models have then been highlighted. Recent retrospective studies advocated improved outcomes in NSCLC diabetic patients receiving metformin with chemoradiotherapy or systemic compounds (including conventional platinum-based chemotherapy and EGFR tyrosine kinase inhibitors). Several prospective randomized trials are therefore currently assessing the addition of metformin to standard therapy in non-diabetic lung cancer patients. This article reviews promises and possible limitations of concurrent metformin used as an anticancer agent in NSCLC patients.

Metformin treatment reduces temozolomide resistance of glioblastoma cells

It has been reported that metformin acts synergistically with temozolomide (TMZ) to inhibit proliferation of glioma cells including glioblastoma multiforme (GBM). However, the molecular mechanism underlying how metformin exerts its anti-cancer effects remains elusive. We used a combined experimental and bioinformatics approach to identify genes and complex regulatory/signal transduction networks that are involved in restoring TMZ sensitivity of GBM cells after metformin treatment. First, we established TMZ resistant GBM cell lines and found that the resistant cells regained TMZ sensitivity after metformin treatment. We further identified that metformin down-regulates SOX2 expression in TMZ-resistant glioma cells, reduces neurosphere formation capacity of glioblastoma cells, and inhibits GBM xenograft growth in vivo. Finally, the global gene expression profiling data reveals that multiple pathways are involved in metformin treatment related gene expression changes, including fatty acid metabolism and RNA binding and splicing pathways. Our work provided insight of the mechanisms on potential synergistic effects of TMZ and metformin in the treatment of glioblastoma, which will in turn yield potentially translational value for clinical applications.

Type I insulin-like growth factor receptor signaling in hematological malignancies

The insulin-like growth factor (IGF) signaling system plays key roles in the establishment and progression of different types of cancer. In agreement with this idea, substantial evidence has shown that the type I IGF receptor (IGF-IR) and its primary ligand IGF-I are important for maintaining the survival of malignant cells of hematopoietic origin. In this review, we discuss current understanding of the role of IGF-IR signaling in cancer with a focus on the hematological neoplasms. We also address the emergence of IGF-IR as a potential therapeutic target for the treatment of different types of cancer including plasma cell myeloma, leukemia, and lymphoma.

Metformin transiently inhibits colorectal cancer cell proliferation as a result of either AMPK activation or increased ROS production

Metformin is a widely used and well-tolerated anti-diabetic drug that can reduce cancer risk and improve the prognosis of certain malignancies. However, the mechanism underlying its anti-cancer effect is still unclear. We studied the anti-cancer activity of metformin on colorectal cancer (CRC) by using the drug to treat HT29, HCT116 and HCT116 p53−/− CRC cells. Metformin reduced cell proliferation and migration by inducing cell cycle arrest in the G0/G1 phase. This was accompanied by a sharp decrease in the expression of c-Myc and down-regulation of IGF1R. The anti-proliferative action of metformin was mediated by two different mechanisms: AMPK activation and increase in the production of reactive oxygen species, which suppressed the mTOR pathway and its downstream targets S6 and 4EBP1. A reduction in CD44 and LGR5 expression suggested that the drug had an effect on tumour cells with stem characteristics. However, a colony formation assay showed that metformin slowed the cells’ ability to form colonies without arresting cell growth, as confirmed by absence of apoptosis, autophagy or senescence. Our finding that metformin only transiently arrests CRC cell growth suggests that efforts should be made to identify compounds that combined with the biguanide can act synergistically to induce cell death.

Metformin partially reverses the carboplatin-resistance in NSCLC by inhibiting glucose metabolism

Platinum-based chemotherapeutic drugs are irreplaceable for the treatment of advanced non-small cell lung cancer (NSCLC). However, acquired drug resistance has become a major obstacle for the clinical application of chemotherapy on NSCLC. In the present study, we established carboplatin-resistant NSCLC models on A549 and PC9 cell lines, which were named A549/R and PC9/R. Besides the low sensitivity of A549/R and PC9/R to carboplatin treatment, they exhibited higher metabolism rate of glucose compared to their parental A549 and PC9 cells, respectively. Mechanically, we confirmed that overexpression of PKM2 in A549/R and PC9/R was responsible for the high glucose metabolism and carboplatin resistance. Metformin, an antidiabetic drug, was observed to increase the sensitivity of carboplatin-resistant NSCLC cells to carboplatin treatment in vitro and in vivo. Mechanically, metformin decreased expression of PKM2 and subsequently inhibited the glucose uptake, lactate generation and ATP production in A549/R and PC9/R. Therefore, metformin promoted carboplatin-induced apoptosis through the mitochondria pathway. In addition, we demonstrated that metformin treatment also impaired the cross-resistance of A549/R and PC9/R to cisplatin, etoposide and 5-fluorouracil.

Insulin-like growth factor 1 signaling is essential for mitochondrial biogenesis and mitophagy in cancer cells

Mitochondrial activity and metabolic reprogramming influence the phenotype of cancer cells and resistance to targeted therapy. We previously established that an insulin-like growth factor 1 (IGF-1)-inducible mitochondrial UTP carrier (PNC1/SLC25A33) promotes cell growth. This prompted us to investigate whether IGF signaling is essential for mitochondrial maintenance in cancer cells and whether this contributes to therapy resistance. Here we show that IGF-1 stimulates mitochondrial biogenesis in a range of cell lines. In MCF-7 and ZR75.1 breast cancer cells, IGF-1 induces peroxisome proliferator-activated receptor γ coactivator 1β (PGC-1β) and PGC-1α-related coactivator (PRC). Suppression of PGC-1β and PRC with siRNA reverses the effects of IGF-1 and disrupts mitochondrial morphology and membrane potential. IGF-1 also induced expression of the redox regulator nuclear factor-erythroid-derived 2-like 2 (NFE2L2 alias NRF-2). Of note, MCF-7 cells with acquired resistance to an IGF-1 receptor (IGF-1R) tyrosine kinase inhibitor exhibited reduced expression of PGC-1β, PRC, and mitochondrial biogenesis. Interestingly, these cells exhibited mitochondrial dysfunction, indicated by reactive oxygen species expression, reduced expression of the mitophagy mediators BNIP3 and BNIP3L, and impaired mitophagy. In agreement with this, IGF-1 robustly induced BNIP3 accumulation in mitochondria. Other active receptor tyrosine kinases could not compensate for reduced IGF-1R activity in mitochondrial protection, and MCF-7 cells with suppressed IGF-1R activity became highly dependent on glycolysis for survival. We conclude that IGF-1 signaling is essential for sustaining cancer cell viability by stimulating both mitochondrial biogenesis and turnover through BNIP3 induction. This core mitochondrial protective signal is likely to strongly influence responses to therapy and the phenotypic evolution of cancer.

Metformin and lung cancer risk in patients with type 2 diabetes mellitus

This study evaluated whether metformin might reduce lung cancer risk. The reimbursement database of the Taiwan's National Health Insurance was used. A sample of 15414 never users and 280159 ever users of metformin (original sample) and a 1:1 matched-pairs of ever and never users (n=15414 in each group, matched sample) were recruited from patients with newly diagnosed type 2 diabetes mellitus during 1999-2005. They were followed until December 31, 2011. Cox regression incorporated with the inverse probability of treatment weighting using propensity score was used to estimate hazard ratios. Results showed that the respective incidence of lung cancer in ever and never users was 173.36 and 292.65 per 100000 person-years in the original sample; and was 211.71 and 292.65, respectively, in the matched sample. The overall hazard ratios (95% confidence intervals) of 0.586 (0.509-0.674) in the original sample and 0.717 (0.584-0.881) in the matched sample suggested a significantly lower risk among metformin users. Hazard ratios comparing the first (<22.60 months), second (22.60-46.67 months) and third (>46.67 months) tertile of cumulative duration of metformin use to never users was 1.163 (1.005-1.348), 0.612 (0.526-0.711) and 0.176 (0.148-0.210), respectively, in the original sample; and was 1.465 (1.131-1.897), 0.758 (0.566-1.016) and 0.228 (1.460-0.357) in the respective tertile of the matched sample. Sensitivity analyses after excluding patients with certain risk factors of cancer and subgroup analyses supported a favorable effect of metformin. In conclusion,metformin use may reduce lung cancer risk in patients with type 2 diabetes mellitus.

Metformin in Lung Cancer: Review of in Vitro and in Vivo Animal Studies

Cancer cells display enhanced growth rates and a resistance to apoptosis. The ability of cancer cells to evade homeostasis and proliferate uncontrollably while avoiding programmed cell death/apoptosis is acquired through mutations to key signaling molecules, which regulate pathways involved in cell proliferation and survival and these mutations allow them to develop resistance to many chemotherapeutic agents, highlighting the need for development of new potent anti-cancer agents. Metformin has long been used as a treatment for type 2 diabetes and has recently attracted attention as a potential agent to be used in the treatment of cancer. The present review summarizes the existing in vitro and in vivo animal studies focusing on the anti-lung cancer effects of metformin and its effects on key proliferative and anti-apoptotic signaling pathways.

Tyrosine Kinase Receptor Landscape in Lung Cancer: Therapeutical Implications

Lung cancer is a heterogeneous disease responsible for the most cases of cancer-related deaths. The majority of patients are clinically diagnosed at advanced stages, with a poor survival rate. For this reason, the identification of oncodrivers and novel biomarkers is decisive for the future clinical management of this pathology. The rise of high throughput technologies popularly referred to as “omics” has accelerated the discovery of new biomarkers and drivers for this pathology. Within them, tyrosine kinase receptors (TKRs) have proven to be of importance as diagnostic, prognostic, and predictive tools and, due to their molecular nature, as therapeutic targets. Along this review, the role of TKRs in the different lung cancer histologies, research on improvement of anti-TKR therapy, and the current approaches to manage anti-TKR resistance will be discussed.

Metformin requires 4E-BPs to induce apoptosis and repress translation of Mcl-1 in hepatocellular carcinoma cells

Metformin inhibits the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, which is frequently upregulated in hepatocellular carcinoma (HCC). Metformin has also been shown to induce apoptosis in this cancer. Here, we investigate whether metformin-induced apoptosis in HCC is mediated by the downstream mTORC1 effectors eukaryotic initiation factor 4E and (eIF4E)-binding proteins (4E-BPs). Further, we ask whether changes in 4E-BPs activity during metformin treatment negatively regulate translation of the anti-apoptotic myeloid cell leukemia 1 (Mcl-1) mRNA. A genetic HCC mouse model was employed to assess the ability of metformin to reduce tumor formation, induce apoptosis, and control 4E-BP1 activation and Mcl-1 protein expression. In parallel, the HCC cell line Huh7 was transduced with scrambled shRNA (control) or shRNAs targeting 4E-BP1 and 4E-BP2 (4E-BP knock-down (KD)) to measure differences in mRNA translation, apoptosis, and Mcl-1 protein expression after metformin treatment. In addition, immunohistochemical staining of eIF4E and 4E-BP1 protein levels was addressed in a HCC patient tissue microarray. We found that metformin decreased HCC tumor burden, and tumor tissues showed elevated apoptosis with reduced Mcl-1 and phosphorylated 4E-BP1 protein levels. In control but not 4E-BP KD Huh7 cells, metformin induced apoptosis and repressed Mcl-1 mRNA translation and protein levels. Immunostaining of HCC patient tumor tissues revealed a varying ratio of eIF4E/4E-BP1 expression. Our results propose that metformin induces apoptosis in mouse and cellular models of HCC through activation of 4E-BPs, thus tumors with elevated expression of 4E-BPs may display improved clinical chemopreventive benefit of metformin.