Synergistic effects of metformin in combination with EGFR-TKI in the treatment of patients with advanced non-small cell lung cancer and type 2 diabetes

Metformin as anticancer agent and adjuvant in cancer combination therapy: Current progress and future prospect

Metformin, as the preferred antihyperglycemic drug for type 2 diabetes, has been found to have a significant effect in inhibiting tumor growth in recent years. However, metformin alone in cancer treatment has the disadvantages of high dose concentrations and few targeted cancer types. Increasing studies have confirmed that metformin can be used in combination with conventional anticancer therapy to obtain more promising clinical benefits, which is expected to be rapidly transformed and applied in clinic. Some combination therapy strategies including metformin combined with chemotherapy, radiotherapy, targeted therapy and immunotherapy have been proven to have more significant antitumor effects and longer survival time than monotherapy. In this review, we summarize the synergistic antitumor effects and mechanisms of metformin in combination with other current conventional anticancer therapies. In addition, we update the research progress and the latest prospect of the metformin-combined application in the cancer treatment. This work could provide more evidence and future direction for the clinical application of metformin in antitumor.

Discovery of 4-((3,4-dichlorophenyl)amino)-2-methylquinolin-6-ol derivatives as EGFR and HDAC dual inhibitors

In patients with non-small cell lung cancer (NSCLC), the standard therapy consists of selective tyrosine kinase inhibitors that target epidermal growth factor receptors (EGFR). Nonetheless, their clinical utility is primarily limited by the development of resistance to drugs. HDAC inhibitors have been shown in studies to reduce the level of EGFR that is expressed and downregulate the EGFR-induced phosphorylation of AKT and ERK. Therefore, dual inhibitors of EGFR and HDAC provide a potential approach as combination treatment synergistically inhibited the growth of NSCLC. Herein, we examined the EGFR inhibition effect of twenty compounds which designed and synthesized by us previously. Among them, compounds 12c and 12d exhibited powerful antiproliferative activity against the NCI-H1975 cell line with IC50 values of 0.48 ± 0.07 and 0.35 ± 0.02 μM, correspondingly. In cell-free kinase assays, both 12c and 12d demonstrated target-specific EGFR inhibition against wild type (EGFRwt). Furthermore, the expression of EGFR and phosphorylation of the EGF-induced pathways were significantly suppressed under the treatment of 12c and 12d. Besides, both histones H3 and H4 exhibited increased levels of acetylation following 12c and 12d treatment. The animal experiments shown that 12d could prevent the growth of tumor, inhibited the expression of EGFR and the phosphorylation levels of p70 S6K, AKT and p38 MAPK in vivo, and did not cause organ damage to the mice during the experiment. Overall, the results illustrated that compound 12c and 12d could serve as effective EGFR and HDAC dual inhibitors in NSCLC cells. Our work offers an alternative strategy for NSCLC therapy.

Interaction of ALK Inhibitors with Polyspecific Organic Cation Transporters and the Impact of Substrate-Dependent Inhibition on the Prediction of Drug-Drug Interactions

Small molecules targeting aberrant anaplastic lymphoma kinase (ALK) are active against ALK-positive non-small-cell lung cancers and neuroblastoma. Several targeted tyrosine kinase inhibitors (TKIs) have been shown to interact with polyspecific organic cation transporters (pOCTs), raising concerns about potential drug-drug interactions (DDIs). The purpose of this study was to assess the interaction of ALK inhibitors with pOCTs and the impact of substrate-dependent inhibition on the prediction of DDIs. Inhibition assays were conducted in transporter-overexpressing cells using meta-iodobenzylguanidine (mIBG), metformin, or 1-methyl-4-phenylpyridinium (MPP+) as the substrate. The half-maximal inhibitory concentrations (IC50) of brigatinib and crizotinib for the substrates tested were used to predict their potential for in vivo transporter mediated DDIs. Here, we show that the inhibition potencies of brigatinib and crizotinib on pOCTs are isoform- and substrate-dependent. Human OCT3 (hOCT3) and multidrug and toxin extrusion protein 1 (hMATE1) were highly sensitive to inhibition by brigatinib and crizotinib for all three tested substrates. Apart from hMATE1, substrate-dependent inhibition was observed for all other transporters with varying degrees of dependency; hOCT1 inhibition showed the greatest substrate dependency, with differences in IC50 values of up to 22-fold across the tested substrates, followed by hOCT2 and hMATE2-K, with differences in IC50 values of up to 16- and 12-fold, respectively. Conversely, hOCT3 inhibition only showed a moderate substrate dependency (IC50 variance < 4.8). Among the substrates used, metformin was consistently shown to be the most sensitive substrate, followed by mIBG and MPP+. Pre-incubation of ALK inhibitors had little impact on their potencies toward hOCT2 and hMATE1. Our results underscore the complexity of the interactions between substrates and the inhibitors of pOCTs and have important implications for the clinical use of ALK inhibitors and their DDI predictions.

Addition of metformin for non-small cell lung cancer patients receiving antineoplastic agents

Background and purpose: Previous studies have found that metformin can inhibit tumor growth and improve outcomes for cancer patients. However, the association between the addition of metformin to the treatment regimen and survival in non-small cell lung cancer (NSCLC) patients receiving antineoplastic agents such as chemotherapy drugs, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), and immune checkpoint inhibitors (ICIs) remains unclear. This study aimed to evaluate the effect of metformin in NSCLC patients who received the aforementioned antineoplastic therapies.

Methods: Several electronic databases were searched for relevant studies published by 10 September 2022. The primary and secondary outcomes were overall survival (OS) and progression-free survival (PFS); eligible studies were those comparing patients with and without the addition of metformin. Hazard ratios (HRs) and 95% confidence intervals (CIs) were combined, with all statistical analyses performed using STATA 15.0.

Results: A total of 19 studies involving 6,419 participants were included, of which six were randomized controlled trials. The overall pooled results indicate that the addition of metformin improved OS (HR = 0.84, 95% CI: 0.71–0.98, p = 0.029) and PFS (HR = 0.85, 95% CI: 0.74–0.99, p = 0.039). However, subgroup analysis based on treatment type and comorbidity of diabetes mellitus demonstrated that improvements in OS and PFS were observed only in diabetic and EGFR-TKI-treated patients (OS: HR = 0.64, 95% CI: 0.45–0.90, p = 0.011; PFS: HR = 0.59, 95% CI: 0.34–1.03, p = 0.061).

Conclusion: Overall, this meta-analysis found that metformin use could improve outcomes for diabetic patients receiving EGFR-TKIs. However, no significant association between the addition of metformin and the survival of non-diabetic NSCLC patients receiving chemotherapy or ICI therapy was identified based on the current evidence.

Exploring the active components and potential mechanisms of Rosa roxburghii Tratt in treating type 2 diabetes mellitus based on UPLC-Q-exactive Orbitrap/MS and network pharmacology

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a global disease with growing prevalence that is difficult to cure. Rosa roxburghii Tratt is an edible and medicinal plant, and modern pharmacological studies have shown that it has potential anti-diabetic activity. This is the first study to explore the active components and potential mechanisms of Rosa roxburghii Tratt fruit for treating T2DM based on UPLC-Q-Exactive Orbitrap/MS and network pharmacology.

METHODS

The active components of Rosa roxburghii Tratt fruit were obtained from UPLC-Q-Exactive Orbitrap/MS analysis and retrieval in the SciFinder, PubMed, Web of Science, and CNKI databases. The potential targets of the active components were obtained from the SwissTargetPrediction and PharmMapper databases. The disease targets for T2DM were obtained from GeneCards, OMIM, TTD, DisGENent, and GEO databases. The intersection of the two datasets was used to obtain the potential targets of Rosa roxburghii Tratt fruit against T2DM. The target protein interaction network was constructed using the String database and Cytoscape software. The R software ClusterProfiler package was used for target enrichment analysis and the Cytoscape CytoNCA plug-in was used to screen core targets. Molecular docking and result visualization were performed using PyMOL and Autodock Vina software.

RESULTS

We obtained 20 bioactive ingredients, including alphitolic acid, quercetin, and ellagic acid, as well as 13 core targets, such as AKT1, TNF, SRC, and VEGFA. All bioactive ingredients in Rosa roxburghii Tratt fruit were active against T2DM-related therapeutic targets. Rosa roxburghii Tratt fruit may play a therapeutic role in T2DM by regulating the PI3K/AKT, RAS, AGE-RAGE, and other signaling pathways.

CONCLUSIONS

This study explored the active components and potential mechanisms of Rosa roxburghii Tratt fruit in the treatment of T2DM, laying the foundation for a further experimental study based on pharmacodynamic substances and their mechanisms of action.

Efficacy of metformin therapy in patients with cancer: a meta-analysis of 22 randomised controlled trials

BACKGROUND

To investigate whether metformin monotherapy or adjunctive therapy improves the prognosis in patients with any type of cancer compared to non-metformin users (age ≥18).

METHODS

Databases (Medline, Embase, and the Cochrane Central Register of Controlled Trials) and clinical trial registries ( ClinicalTrials.gov ; the World Health Organization International Clinical Trials Registry Platform) were screened for randomized, controlled trials (RCT) reporting at least progression-free survival (PFS) and/or overall survival (OS). Main outcome measures included hazard ratios (HR), and combined HRs and 95% confidence intervals (CI) were calculated using random-effects models.

RESULTS

Of the 8419 records screened, 22 RCTs comprising 5943 participants were included. Pooled HRs were not statistically significant in both PFS (HR 0.97, 95% CI 0.82-1.15, I² = 50%) and OS (HR 0.98, 95% CI 0.86-1.13, I² = 33%) for patients with cancer between the metformin and control groups. Subgroup analyses demonstrated that metformin treatment was associated with a marginally significant improvement in PFS in reproductive system cancers (HR 0.86, 95% CI 0.74-1.00) and a significantly worse PFS in digestive system cancers (HR 1.45, 95% CI 1.03-2.04). The PFS or OS was observed consistently across maintenance dose, diabetes exclusion, median follow-up, risk of bias, and combined antitumoral therapies.

CONCLUSION

Metformin treatment was not associated with cancer-related mortality in adults compared with placebo or no treatment. However, metformin implied beneficial effects in the PFS of the patients with reproductive system cancers but was related to a worse PFS in digestive system cancers.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42022324672.

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.

The Survival Benefit for Optimal Glycemic Control in Advanced Non-Small Cell Lung Cancer Patients With Preexisting Diabetes Mellitus

Background

Diabetes mellitus (DM) is a frequent comorbidity in patients with cancer. This study aimed to evaluate the prognosis of advanced non-small cell lung cancer (NSCLC) patients with DM and to assess whether an optimal glycemic control improves overall survival (OS).

Methods

A total of 1279 advanced NSCLC patients including 300 (23.5%) with preexisting DM were retrospectively reviewed. The continuous relationship between glycated hemoglobin A1C (HbA1c) level and OS was analyzed by restricted cubic spline (RCS) function. Optimal HbA1c cut-off point was determined using X-tile analysis. Survival was analyzed with the Kaplan–Meier method and compared among groups stratified by diabetes status and HbA1c. Multivariable Cox proportional hazards regression analysis was employed to identify prognostic factors for OS after adjusting for baseline characteristics.

Results

DM and non-DM patients had similar OS (median (95% CI): 22.85 (20.05-26.73) vs. 22.22 (20.35-24.76) months, P=0.950). The multivariate Cox regression analyses showed that DM status was not a prognostic factor for OS (HR: 0.952, 95% CI: 0.808-1.122, P=0.559). However, there existed a non-linear but generally positive relationship between the elevated HbA1c level and increased risk of overall mortality. HbA1c > 6.6% was a negative prognostic factor for OS (HR: 1.593, 95% CI: 1.113-2.280, P=0.011). The median OS (95% CI) for nondiabetic patients, DM patients with HbA1c ≤6.6% and those with HbA1c > 6.6% was 22.22 (20.01-24.43), 25.28 (21.79-28.77) and 15.45 (7.57-23.33) months, respectively. Well-controlled DM patients had a comparable crude OS (HR (95% CI): 0.90 (0.76-1.08), P=0.273] compared to nondiabetic patients while patients with HbA1c>6.6% had a worse crude OS than patients without DM (HR (95% CI): 1.70 (1.24-2.34), P=0.001]. The survival benefit of good HbA1c control was prominent in all subgroups.

Conclusion

Impaired glycemic level negatively affects survival for patients with advanced NSCLC while proper glycemic control with HbA1c ≤6.6% improves the OS.

P53 mediates the protective effects of metformin in inflamed lung endothelial cells

The endothelial barrier regulates interstitial fluid homeostasis by transcellular and paracellular means. Dysregulation of this semipermeable barrier may lead to vascular leakage, edema, and accumulation of pro-inflammatory cytokines, inducing microvascular hyperpermeability. Investigating the molecular pathways involved in those events will most probably provide novel therapeutic possibilities in pathologies related to endothelial barrier dysfunction. Metformin (MET) is an anti-diabetic drug, opposes malignancies, inhibits cellular transformation, and promotes cardiovascular protection. In the current study, we assess the protective effects of MET in LPS-induced lung endothelial barrier dysfunction and evaluate the role of P53 in mediating the beneficial effects of MET in the vasculature. We revealed that this biguanide (MET) opposes the LPS-induced dysregulation of the lung microvasculature, since it suppressed the formation of filamentous actin stress fibers, and deactivated cofilin. To investigate whether P53 is involved in those phenomena, we employed the fluorescein isothiocyanate (FITC) - dextran permeability assay, to measure paracellular permeability. Our observations suggest that P53 inhibition increases paracellular permeability, and MET prevents those effects. Our results contribute towards the understanding of the lung endothelium and reveal the significant role of P53 in the MET-induced barrier enhancement.

Therapeutic approaches targeting molecular signaling pathways common to diabetes, lung diseases and cancer

Diabetes mellitus (DM), is the most common metabolic disease and is characterized by sustained hyperglycemia. Accumulating evidences supports a strong association between DM and numerous lung diseases including chronic obstructive pulmonary disease (COPD), fibrosis, and lung cancer (LC). The global incidence of DM-associated lung disorders is rising and several ongoing studies, including clinical trials, aim to elucidate the molecular mechanisms linking DM with lung disorders, in particular LC. Several potential mechanisms, including hyperglycemia, hyperinsulinemia, glycation, inflammation, and hypoxia, are cited as plausible links between DM and LC. In addition, studies also propose a connection between the use of anti-diabetic medications and reduction in the incidence of LC. However, the exact cause for DM associated lung diseases especially LC is not clear and is an area under intense investigation. Herein, we review the biological links reported between DM and lung disorders with an emphasis on LC. Furthermore, we report common signaling pathways (eg: TGF-β, IL-6, HIF-1, PDGF) and miRNAs that are dysregulated in DM and LC and serve as molecular targets for therapy. Finally, we propose a nanomedicine based approach for delivering therapeutics (eg: IL-24 plasmid DNA, HuR siRNA) to disrupt signaling pathways common to DM and LC and thus potentially treat DM-associated LC. Finally, we conclude that the effective modulation of commonly regulated signaling pathways would help design novel therapeutic protocols for treating DM patients diagnosed with LC.

The role of metformin on lung cancer survival: the first systematic review and meta-analysis of observational studies and randomized clinical trials

PURPOSE

To assess the effects of metformin use on lung cancer (LC) survival according to summarized results from observational studies (OBs) and randomized clinical trials (RCTs).

METHODS

We systematically searched electronic databases and, to our knowledge, for the first time, RCTs were included in a systematic review and meta-analysis about the role of metformin on LC survival. We carried out meta-analyses separately for OBs and RCTs. Analyses for overall survival (OS) concerning OBs were stratified by studies with and without time-dependent approach. Subgroup analyses were adopted for OBs to identify the sources of heterogeneity. Included studies were assessed for quality.

RESULTS

We identified ten OBs and four RCTs. For OBs, metformin use was associated with improved OS for LC patients. Only two studies used time-dependent approach in which a higher ratio was found when compared to the non-use of the time-dependent analysis in eight studies. OBs were classified as high quality but the risk of bias was "unclear" in eight OBs due to absence of the time-dependent analysis. For RCTs, metformin use was not beneficial for OS and neither for progression-free survival. Heterogeneous quality was found among RCTs. Sources of bias that could alter significantly the results or raise doubts were identified in RCTs.

CONCLUSION

Time-dependent analysis should be considered an appropriate strategy for OBs focused on the metformin use for LC patients' survival, and further studies applying this approach are required. More well-designed RCTs are needed to provide consistent results for the association between metformin use and LC survival.

Does metformin improve the efficacy of standard epidermal growth factor receptor-tyrosine kinase inhibitor treatment for patients with advanced non-small-cell lung cancer?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether metformin improved the efficacy of standard epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment for patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer. A total of 99 papers were found using the reported search, of which 4 represented the best evidence to answer this clinical question. The authors, journal, publication date, country, study type, treatment regimen, relevant outcomes and results of these papers are tabulated. We concluded that the addition of metformin to EGFR-TKI might improve the survival of patients with EGFR-mutated non-small-cell lung cancer and diabetes mellitus type 2. However, for non-diabetic non-small-cell lung cancer patients with EGFR mutation, the efficiency of additional metformin in EGFR-TKI treatment remains unclear because of the conflicting results of only 2 available studies.

Metformin Adjunct With Antineoplastic Agents for the Treatment of Lung Cancer: A Meta-Analysis of Randomized Controlled Trials and Observational Cohort Studies

Objective: Resistance to anticancer agents ensures a poor prognosis in patients with lung cancer. Metformin could enhance the anticancer effects of standard antineoplastic agents [traditional chemotherapy drugs, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), or immune checkpoint inhibitors (ICIs)]; however, it is unclear whether metformin can be combined with antineoplastic agents in the treatment of lung cancer. To explore the efficacy of combinational strategies, we performed a systematic review and meta-analysis for diabetic and non-diabetic patients with lung cancer.

Method: An electronic literature search was performed to obtain relevant randomized controlled trials (RCTs) and observational cohort studies. Hazard ratios (HR) with 95% confidence intervals (CI) of overall survival (OS) and progression-free survival (PFS) outcomes were extracted. Subgroup analysis by antineoplastic agents, study type, histology and clinical stage were investigated.

Results: 14 studies (three RCTs and eleven observational cohort studies) consisting 3,856 patients were included in the meta-analysis. Compared to standard antineoplastic agents alone (traditional chemotherapy drugs, EGFR-TKIs or ICIs), the antineoplastic agents combined with metformin significantly improved OS (HR 0.73, 95% CI 0.66–0.81, p < 0.00001) and PFS (HR 0.72, 95% CI 0.59–0.88, p = 0.001); a similar association was found in observational evidence. Limited data from RCTs showed no differences in OS or PFS.

Conclusion: Metformin plus antineoplastic agents may improve survival outcomes of patients with lung cancer. Further investigation is needed.

Benefit from Adjuvant TKIs Versus TKIs Plus Chemotherapy in EGFR-Mutant Stage III-pN2 Lung Adenocarcinoma

BACKGROUND

Recent studies have demonstrated benefits from adjuvant tyrosine-kinase inhibitors (TKIs) compared with chemotherapy in non-small cell lung cancer. We launched a multi-center retrospective study to evaluate the efficacy and toxicity of adjuvant TKIs with or without chemotherapy in epidermal growth factor receptor (EGFR)-mutant stage III-pN2 lung adenocarcinoma.

METHODS

Two hundred and seventy-four consecutive cases with stage III-pN2 lung adenocarcinoma and complete resection have been investigated. Clinic-pathologic characteristics, adjuvant treatments, long-term survivals, and toxicities were documented. Risk factors of distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) were evaluated.

RESULTS

There were 52 (19.0%) patients treated with adjuvant TKIs alone, 199 (72.6%) with adjuvant chemotherapy alone, and 23 (8.4%) with both. After a median follow-up time of 29 months, the two-year DMFS, DFS, and OS was 61.2%, 54.1%, and 91.2%, respectively. According to univariable analyses, the risk factors were lymphovascular invasion (p < 0.001), extranodal extension (p = 0.005), and adjuvant systemic therapy (p = 0.006) for DMFS, EGFR mutation type (p = 0.025), lymphovascular invasion (p = 0.013), extranodal extension (p = 0.004), and adjuvant systemic therapy (p < 0.001) for DFS, and EGFR mutation type (p < 0.001) for OS. Multivariable analyses indicated that the independent prognostic factors were adjuvant systemic therapy (TKIs vs. TKIs+chemotherapy, Harzard ratio (HR) = 0.40; p = 0.036; TKIs vs. chemotherapy, HR = 0.38; p = 0.004), lymphovascular invasion (yes vs. no, HR = 2.22; p = 0.001) for DMFS, and adjuvant systemic therapy (TKIs vs. TKIs+chemotherapy, HR = 0.42; p = 0.034; TKIs vs. chemotherapy, HR = 0.33; p < 0.001) for DFS. No significant difference was found in the incidence of Grade 3-4 toxicities between groups (p = 0.445).

CONCLUSIONS

Adjuvant TKIs might be a beneficial choice compared with adjuvant chemotherapy or combination systemic treatments.

Concurrent use of metformin enhances the efficacy of EGFR-TKIs in patients with advanced EGFR-mutant non-small cell lung cancer-an option for overcoming EGFR-TKI resistance

Background

Resistance is almost inevitable and is still a major obstacle in epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy. Only limited relevant clinical studies evaluated the therapeutic effects by combing metformin and EGFR-TKIs in non-small cell lung cancer (NSCLC) patients. Therefore, we evaluated the efficacy of concurrent use of metformin with EGFR-TKIs, and assessed whether the addition of metformin may improve clinical outcomes and delay the occurrence of EGFR-TKI resistance.

Methods

We conducted cell proliferation and apoptosis assay for investigation of metformin in combination with EGFR-TKIs to overcome EGFR-TKI resistance in vitro. Furthermore, we retrospectively reviewed clinicopathological characteristics and therapeutic outcomes of EGFR-mutant advanced NSCLC diabetic patients who received EGFR-TKIs with or without concurrent use of metformin.

Results

In vitro experiment, metformin showed synergistic interaction both with gefitinib in PC9R (CI =0.77) and with osimertinib in PC9R/OR (CI =0.77) in proliferation inhibition assay. Metformin can also augment apoptosis effect of these TKI-resistant cells to EGFR-TKIs. In retrospective cohort, a total of 85 patients were identified (cohort A), in which 28 patients had concurrent use of metformin. The objective response rate in metformin use group was significantly higher (85.7% vs. 47.4%, P=0.001). The median progression-free survival (PFS) and overall survival (OS) in metformin use group were significantly longer (21.6 vs. 9.2 months, P=0.000; 48.4 vs. 36.6 months, P=0.049). Further analysis revealed that metformin obviously prolonged the median PFS2 of osimertinib treatment among patients who progressed to prior line EGFR-TKIs due to secondary EGFR T790M mutation (cohort B).

Conclusions

Our study suggest that concurrent use of metformin could be beneficial to EGFR-mutant NSCLC patients treated with either first-line EGFR-TKIs or second-line osimertinib.

Metformin enhances the cytotoxic effect of nilotinib and overcomes nilotinib resistance in chronic myeloid leukemia cells

BACKGROUND/AIMS

Nilotinib is used for treating patients with imatinib-sensitive or -resistant chronic myeloid leukemia (CML); however, nilotinib-resistant cases have been observed in recent years. In addition, a considerable number of patients receiving nilotinib developed diabetes. Metformin is a front-line drug for the treatment of type 2 diabetes, and several studies have shown that diabetes patients treated with metformin have reduced incidence of cancer. This study aimed to define the effect of metformin on CML cells to determine whether metformin overcomes nilotinib resistance, and to identify novel targets for the treatment of nilotinib resistance.

METHODS

We observed the effects of metformin and nilotinib on K562 and KU812 human CML cell lines. Nilotinib-resistant CML cell lines were generated by exposing cells to gradually increasing doses of nilotinib. Then, we investigated the driving force that makes resistance to nilotinib and the effect of metformin on the driving force.

RESULTS

Sub-toxic doses of metformin enhanced nilotinib efficacy by reducing Bcl-xL expression, which induces apoptosis in CML cells. Next, we generated nilotinib-resistant K562 and KU812 cell lines that overexpressed the c-Jun N-terminal kinase (JNK) gene. JNK silencing by a JNK inhibitor restored sensitivity to nilotinib. Furthermore, metformin was effective in decreasing phosphorylated JNK levels, restoring nilotinib sensitivity. Combined treatment with nilotinib and metformin was more effective than combined treatment with nilotinib and a JNK inhibitor in terms of cell proliferation inhibition.

CONCLUSION

This study suggested that combination therapy with metformin and nilotinib may have clinical benefits of enhancing antileukemia efficacy and overcoming resistance to nilotinib.

Metformin use and lung cancer survival: a population-based study in Norway

BACKGROUND

We assessed associations between metformin use and survival in a nationwide Norwegian cohort of lung cancer (LC) patients.

METHODS

The study linked 22,324 LC patients from the Cancer Registry of Norway diagnosed 2005-2014 with the Norwegian Prescription Database. We estimated associations of pre- and post-diagnostic metformin use with overall survival (OS) and LC-specific survival (LCSS) using multivariable time-fixed and time-dependent Cox regression.

RESULTS

Pre-diagnostic metformin use was not associated with improved survival in all patients. Nevertheless, pre-diagnostic metformin use was associated with better LCSS in squamous cell carcinoma (SCC) patients (hazard ratio (HR) = 0.79; 95% confidence interval (CI) 0.62-0.99) and in patients with regional stage SCC (HR = 0.67; 95%CI 0.47-0.95). Post-diagnostic metformin use was associated with improved LCSS in all patients (HR = 0.83; 95%CI 0.73-0.95), in patients with SCC (HR = 0.75; 95%CI 0.57-0.98), regional stage LC (HR = 0.74; 95%CI 0.59-0.94), and regional stage SCC (HR = 0.57; 95%CI 0.38-0.86). OS showed similar results. Analyses of cumulative use showed a dose-response relationship in all patients, patients with adenocarcinoma and SCC, and with regional and metastatic LC.

CONCLUSIONS

Metformin use was associated with improved survival, especially LCSS in patients with regional stage SCC. Further prospective studies are required to clarify the role of metformin in LC treatment.

Metformin and Malignant Tumors: Not Over the Hill

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

Shining a light on metabolic vulnerabilities in non-small cell lung cancer

Metabolic reprogramming is a hallmark of cancer which contributes to essential processes required for cell survival, growth, and proliferation. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and its genomic classification has given rise to the design of therapies targeting tumors harboring specific gene alterations that cause aberrant signaling. Lung tumors are characterized with having high glucose and lactate use, and high heterogeneity in their metabolic pathways. Here we review how NSCLC cells with distinct mutations reprogram their metabolic pathways and highlight the potential metabolic vulnerabilities that might lead to the development of novel therapeutic strategies.

The potential adjunctive benefit of adding metformin to standard treatment in inoperable cancer patients: a meta-analysis of randomized controlled trials

Background

Recently, there have been several randomized clinical trials (RCTs) conducted to evaluate the efficacy and safety of metformin plus standard treatment in inoperable cancer patients. Our meta-analysis aimed to assess the efficacy of metformin in combination with standard treatment in inoperable cancer patients.

Methods

PubMed and Embase databases were systematically searched for relevant RCTs investigating the efficacy of adding metformin to standard treatment for cancer patients. The pooled relative risk (RR) for tumor response and safety was calculated to assess the efficacy of combining metformin with standard treatment. Meta-analysis was subsequently performed to pool the hazard ratio (HR) for overall survival (OS) and progression-free survival (PFS).

Results

Ten RCTs comprising 1033 patients were included in our current meta-analysis. In patients with breast cancer, results of meta-analysis showed that the addition of metformin to standard treatment was beneficial to objective response rate (ORR) with 30.3% (33/109) in the metformin plus standard treatment group and 16.1% (18/112) in the placebo group (RR 1.92, 95% CI: 1.19–3.10, P=0.008). OS and PFS were not significantly improved in patients who received metformin plus standard treatment compared with those who received placebo plus standard treatment (OS: HR 1.02, 95% CI: 0.71–1.46, P=0.916; PFS: HR 1.14, 95% CI: 0.86–1.50, P=0.366). For lung cancer patients, meta-analysis results showed adding metformin to standard treatment could benefit ORR (metformin 65.3% vs. placebo 54.6%, RR 1.22, 95% CI: 1.03–1.43, P=0.018) with no significant survival benefit in the metformin group. For patients with pancreatic cancer, the pooled ORR was 17.6% (16/91) in metformin plus standard treatment group and 20% (18/90) in the placebo group, indicating metformin did not benefit ORR (RR 0.85, 95% CI: 0.49–1.49, P=0.576). Besides, the addition of metformin to standard treatment did not increase the incidence rate of adverse effects.

Conclusions

Our results indicated that addition of metformin to standard treatment was beneficial to ORR in inoperable breast or lung cancer patients without increasing the incidence of adverse effects. However, adding metformin to standard treatment could not benefit OS and PFS.

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.

The efficacy of first-line tyrosine kinase inhibitors combined with co-medications in Asian patients with EGFR mutation non-small cell lung cancer

The real-world efficacy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR-activating mutations remains unclear. We conducted a retrospective cohort study using data from the claims database of Taipei Veterans General Hospital to perform direct comparisons of these three EGFR-TKIs (gefitinib, erlotinib, and afatinib) combined with co-medications (metformin, statins, antacids, and steroids). Stage IIIB and IV NSCLC patients with EGFR mutations receiving EGFR-TKIs as first-line treatment for > 3 months between 2011 and 2016 were enrolled. The primary endpoint was time to treatment failure (TTF). Patients who had received co-medications (≥ 28 defined daily doses) in the first 3 months of EGFR-TKI therapy were assigned to co-medications groups. A total of 853 patients treated with gefitinib (n = 534), erlotinib (n = 220), and afatinib (n = 99) were enrolled. The median duration of TTF was 11.5 months in the gefitinib arm, 11.7 months in the erlotinib arm, and 16.1 months in the afatinib arm (log-rank test, P < 0.001). After adjustments, afatinib showed lower risk of treatment failure compared with gefitinib (hazard ratio [HR] 0.54, 95% confidence interval [CI] 0.41–0.71) and erlotinib (HR 0.62, 95% CI 0.46–0.83). The risk of treatment failure in patients treated with EGFR-TKIs who received concomitant systemic glucocorticoid therapy was higher than in those treated with EGFR-TKI monotherapy (HR 1.47, 95% CI 1.08–2.01). Afatinib or erlotinib use was associated with a lower risk of treatment failure in patients with advanced NSCLC harboring EGFR mutations compared to gefitinib use. Concurrent use of systemic glucocorticoids was linked to higher risk of treatment failure.

The effect of metformin on lung cancer risk and survival in patients with type 2 diabetes mellitus: A meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Metformin has received increasing attention owing to its potential protective effect against cancer. We aimed to summarize evidence regarding the association between metformin and the risk or survival in lung cancer patients with type 2 diabetes.

METHODS

We selected observational studies examining the association between exposure to metformin and the risk or survival in lung cancer. Available publications were searched in PubMed, Cochrane Library, ScienceDirect, Wiley and SpringerLink databases. Meta-analysis was performed with hazard ratios (HRs) and 95% confidence intervals (95% CIs) as effect measures for risk or survival in lung cancer.

RESULTS

Eighteen studies (eight on lung cancer risk and ten on lung cancer survival) were included. Metformin treatment was associated with decreased lung cancer incidence (HR 0.78; 95% CI 0.70-0.86) and increased lung cancer survival (HR 0.65; 95% CI 0.55-0.77). In the subgroup analysis by ethnicity, a significant protective effect of metformin use on lung cancer risk was observed among Asian patients (HR 0.66; 95% CI 0.56-0.76), but not in European patients. On the other hand, the protective effect of metformin use on lung cancer survival was observed in both Asian (HR 0.57; 95% CI 0.49-0.66) and non-Asian (HR 0.79; 95% CI 0.71-0.88) patients. In the subgroup analysis by histology, a protective effect of metformin on lung cancer survival was observed in both non-small-cell lung cancer (HR 0.68; 95% CI 0.54-0.84) and small-cell lung cancer (HR 0.52; 95% CI 0.39-0.69). Funnel plot showed that no significant publication bias existed.

CONCLUSIONS

Our findings demonstrate that metformin is significantly associated with a decreased risk and increased survival in lung cancer.

A Cohort Study of Exposure to Antihyperglycemic Therapy and Survival in Patients with Lung Cancer

We evaluated the effect of antihyperglycemic therapy on the survival of patients with lung cancer (LC). The analysis included patients with LC and concomitant type 2 diabetes. 15,929 patients were classified into five groups: metformin users, insulin users, metformin and insulin users, sulphonylurea users and non-diabetic group. A multivariate analysis showed that exposure to either metformin or to insulin was associated with a lower risk of LC-specific mortality, and this approached statistical significance (HR 0.82, 95% CI 0.72–92 for metformin and HR 0.65, 95% CI 0.44–95 for insulin). When deaths from all causes were considered, only metformin exposure was associated with a significantly lower risk of death (HR 0.82, 95% CI 0.73–0.92). Users of sulphonylurea were at a higher risk of LC-specific and overall mortality (HRs 1.19, 95% CI 0.99–1.43 and 1.22, 95% CI 1.03–1.45). Our study shows a positive effect of metformin on the survival of patients with LC. Moreover, our results show that exposure to insulin was associated with a lower risk of LC-specific mortality, but not with deaths from all causes. The study results suggested that users of sulphonylurea may be at a higher risk of LC-specific and overall mortality.

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.

Metformin Prolongs Survival in Type 2 Diabetes Lung Cancer Patients With EGFR-TKIs

Background: Metformin use reportedly reduces cancer risk and improves survival in lung cancer patients. This study aimed to investigate the effect of metformin use in patients with diabetes mellitus (DM) and lung cancer receiving epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy. Methods: A nationwide, population-based cohort study was conducted using the Taiwan National Health Insurance Research Database. From January 1, 2004, to December 31, 2012, a total of 373 metformin and 1260 non-metformin lung cancer cohorts with type 2 DM and EGFR-TKI treatment were studied. Results: Metformin use was significantly associated with a reduced risk of death (hazard ratio: 0.73, 95% confidence interval [CI]: 0.62-0.85, P < .001), as well as a significantly longer median progression-free survival (9.2 months, 95% CI: 8.6-11.7, vs 6.4 months, 95% CI: 5.9-7.2 months, P < .001) and median overall survival (33.4 months, 95% CI: 29.4-40.2, vs 25.4 months, 95% CI: 23.7-27.2 months, P < 0.001). Conclusions: In conclusion, metformin may potentially enhance the therapeutic effect and increase survival in type 2 DM patients with lung cancer receiving EGFR-TKI therapy.

The addition of metformin to systemic anticancer therapy in advanced or metastatic cancers: a meta-analysis of randomized controlled trials

Preclinical studies have demonstrated that metformin has anticancer properties and act in additive or synergistic way when combined with anticancer agents. We conducted this meta-analysis of randomized clinical trials to evaluate the effect of metformin added to systemic anticancer therapy in patients with advanced or metastatic cancer. A computerized systematic electronic search was performed using PubMed, PMC, EMBASE, Cochrane Library, and Web of Science databases (up to June 2020). From nine randomized clinical trials, 821 patients were included in the pooled analyses of odds ratios (ORs) with 95% confidence intervals (CIs) for overall response rate (ORR) and hazard ratios (HRs) with 95% CIs for progression-free survival (PFS) and overall survival (OS). The concomitant use of metformin with systemic anticancer therapy did not increase tumor response (the pooled OR of ORR = 1.23, 95% CI: 0.89-1.71, p = 0.21), compared with anticancer therapy alone. In terms of survival, metformin added to anticancer agents failed to prolong PFS (HR = 0.95, 95% CI: 0.75-1.21, p = 0.68) and OS (HR = 0.97, 95% CI: 0.80-1.16, p = 0.71). In conclusion, this meta-analysis of randomized clinical trials indicates that the addition of metformin to systemic anticancer therapy has no clinical benefits in patients with advanced or metastatic cancer.

Current progress and future perspectives of polypharmacology : From the view of non-small cell lung cancer

A pre-eminent subtype of lung carcinoma, Non-small cell lung cancer accounts for paramount causes of cancer-associated mortality worldwide. Undeterred by the endeavour in the treatment strategies, the overall cure and survival rates for NSCLC remain substandard, particularly in metastatic diseases. Moreover, the emergence of resistance to classic anticancer drugs further deteriorates the situation. These demanding circumstances culminate the need of extended and revamped research for the establishment of upcoming generation cancer therapeutics. Drug repositioning introduces an affordable and efficient strategy to discover novel drug action, especially when integrated with recent systems biology driven stratagem. This review illustrates the trendsetting approaches in repurposing along with their numerous success stories with an emphasize on the NSCLC therapeutics. Indeed, these novel hits, in combination with conventional anticancer agents, will ideally make their way the clinics and strengthen the therapeutic arsenal to combat drug resistance in the near future.

Effect of Metformin Plus Tyrosine Kinase Inhibitors Compared With Tyrosine Kinase Inhibitors Alone in Patients With Epidermal Growth Factor Receptor-Mutated Lung Adenocarcinoma: A Phase 2 Randomized Clinical Trial

IMPORTANCE

Metformin hydrochloride is emerging as a repurposed anticancer drug. Preclinical and retrospective studies have shown that it improves outcomes across a wide variety of neoplasms, including lung cancer. Particularly, evidence is accumulating regarding the synergistic association between metformin and epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs).

OBJECTIVE

To assess the progression-free survival (PFS) in patients with advanced lung adenocarcinoma who received treatment with EGFR-TKIs plus metformin compared with those who received EGFR-TKIs alone.

DESIGN, SETTING, AND PARTICIPANTS

Open-label, randomized, phase 2 trial conducted at the Instituto Nacional de Cancerología (INCan), Mexico City, Mexico. Eligible patients were 18 years or older, had histologically confirmed stage IIIB-IV lung adenocarcinoma with an activating EGFR mutation.

INTERVENTIONS

Patients were randomly allocated to receive EGFR-TKIs (erlotinib hydrochloride, afatinib dimaleate, or gefitinib at standard dosage) plus metformin hydrochloride (500 mg twice a day) or EGFR-TKIs alone. Treatment was continued until occurrence of intolerable toxic effects or withdrawal of consent.

MAIN OUTCOMES AND MEASURES

The primary outcome was PFS in the intent-to-treat population. Secondary outcomes included objective response rate, disease control rate, overall survival (OS), and safety.

RESULTS

Between March 31, 2016, and December 31, 2017, a total of 139 patients (mean [SD] age, 59.4 [12.0] years; 65.5% female) were randomly assigned to receive EGFR-TKIs (n = 70) or EGFR-TKIs plus metformin (n = 69). The median PFS was significantly longer in the EGFR-TKIs plus metformin group (13.1; 95% CI, 9.8-16.3 months) compared with the EGFR-TKIs group (9.9; 95% CI, 7.5-12.2 months) (hazard ratio, 0.60; 95% CI, 0.40-0.94; P = .03). The median OS was also significantly longer for patients receiving the combination therapy (31.7; 95% CI, 20.5-42.8 vs 17.5; 95% CI, 11.4-23.7 months; P = .02).

CONCLUSIONS AND RELEVANCE

To our knowledge, this is the first study to prospectively show that the addition of metformin to standard EGFR-TKIs therapy in patients with advanced lung adenocarcinoma significantly improves PFS. These results justify the design of a phase 3, placebo-controlled study.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03071705.

Combination of Metformin and Gefitinib as First-Line Therapy for Nondiabetic Advanced NSCLC Patients with EGFR Mutations: A Randomized, Double-Blind Phase II Trial

PURPOSE

Preclinical and retrospective studies suggested a role for metformin in sensitizing patients who have diabetes with non-small cell lung cancer (NSCLC) to EGFR tyrosine kinase inhibitors (TKIs). We therefore examined its effects in combination with gefitinib in patients without diabetes harboring EGFR mutations (EGFRm).

PATIENTS AND METHODS

A total of 224 patients without diabetes with treatment-naïve stage IIIB-IV EGFRm NSCLC were randomly assigned in a 1:1 ratio to receive gefitinib plus either metformin or placebo. The primary endpoint was progression-free survival (PFS) rate at 1 year and secondary endpoints included overall survival (OS), PFS, objective response rate (ORR), and safety. Serum levels of IL6 were also examined in an exploratory analysis.

RESULTS

The median duration of follow-up was 19.15 months. The estimated 1-year PFS rates were 41.2% [95% confidence interval (CI), 30.0-52.2] with gefitinib plus metformin and 42.9% (95% CI, 32.6-52.7) with gefitinib plus placebo (P = 0.6268). Median PFS (10.3 months vs. 11.4 months) and median OS (22.0 months vs. 27.5 months) were numerically lower in the metformin group, while ORRs were similar between the two arms (66% vs. 66.7%). No significant treatment group differences were detected across all subgroups with respect to PFS, including those with elevated levels of IL6. Metformin combined with gefitinib resulted in a remarkably higher incidence of diarrhea compared with the control arm (78.38% vs. 43.24%).

CONCLUSIONS

Our study showed that addition of metformin resulted in nonsignificantly worse outcomes and increased toxicity and hence does not support its concurrent use with first-line EGFR-TKI therapy in patients without diabetes with EGFRm NSCLC.

Clinical outcomes in non-small-cell lung cancer patients receiving concurrent metformin and immune checkpoint inhibitors

Aim:

To study the clinical benefits of concurrent metformin and immune checkpoint inhibitors (ICIs) in non-small-cell lung cancer patients.

Materials & methods:

This is a retrospective review of 50 non-small-cell lung cancer patients receiving ICIs with metformin (cohort A) or without metformin (cohort B). Patients were also stratified by ICIs as second-/third-line therapy.

Results:

Overall response rate and disease control rate were higher in cohort A (41.1 vs 30.7%, p = 0.4 and 70.5 vs 61.6%, p = 0.5, respectively). Median overall survival and progression-free survival were also higher in cohort A (11.5 vs 7.6 months, p = 0.5 and 4.0 vs 3.0 months, p = 0.6, respectively). On subset analysis (second-/third-line ICIs), overall response rate, disease control rate, median overall survival, progression-free survival were also higher in cohort A.

Conclusion:

Despite the small-sample size, we observed improved clinical outcomes in patients who received ICIs in combination with metformin.

Immune Cell Metabolism in Tumor Microenvironment

Tumor microenvironment (TME) is composed of tumor cells, immune cells, cytokines, extracellular matrix, etc. The immune system and the metabolisms of glucose, lipids, amino acids, and nucleotides are integrated in the tumorigenesis and development. Cancer cells and immune cells show metabolic reprogramming in the TME, which intimately links immune cell functions and edits tumor immunology. Recent findings in immune cell metabolism hold the promising possibilities toward clinical therapeutics for treating cancer. This chapter introduces the updated understandings of metabolic reprogramming of immune cells in the TME and suggests new directions in manipulation of immune responses for cancer diagnosis and therapy.

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.

Metformin Inhibit Lung Cancer Cell Growth and Invasion in Vitro as Well as Tumor Formation in Vivo Partially by Activating PP2A

Background

The aim of this study was to investigate whether PP2A activation is involved in the anti-cancer activity of metformin.

Material/Methods

A549 and H1651 human lung cancer cells were constructed with stable α4 overexpression (O/E α4) or knockdown of PP2A catalytic subunit A/B(sh-PP2Ac). Influences of okadaic acid (OA) treatment, O/E α4 or sh-PP2Ac on metformin treated cells were investigated by cell viability, proliferation, apoptosis, and Transwell invasion assay in vitro. Protein expression levels of Bax, Bcl-2, Myc, and Akt as well as serine phosphorylation level of Bax, Myc, and Akt were examined by western blot. For in vivo assays, wild type (WT) or modified A549 cells were subcutaneously injected in nude mice, and metformin treatment on these xenografted tumors were assayed by tumor formation assay and western blot detecting cell proliferation marker PCNA (proliferating cell nuclear antigen) as well as protein expression level and serine phosphorylation level of Akt and Myc.

Results

Metformin treatment significantly reduced A549 or H1651 cell growth and invasive capacity in vitro as well as Ser184 phosphorylation of Bax, Ser62 phosphorylation of Myc, and Ser473 phosphorylation of Akt, all of which could be partially attenuated by OA treatment, O/E α4 or sh-PP2Ac. Metformin treatment also significantly reduced tumor formation in vivo as well as protein expression of PCNA, Akt, Myc, and serine phosphorylation of the latter 2, which can be partially blocked by O/E α4 or sh-PP2Ac.

Conclusions

Metformin reduced lung cancer cell growth and invasion in vitro as well as tumor formation in vivo partially by activating PP2A.

Impact of metformin use on survival outcomes in non-small cell lung cancer treated with platinum

Preclinical evidence suggests that metformin, a widely used antidiabetic drug, may have a sensitizing effect on platinum. The purpose of this study was to evaluate the survival outcomes for non-small cell lung cancer (NSCLC) patients with type 2 diabetes mellitus (T2DM) using metformin during platinum-based chemotherapy.The clinicopathological parameters and survival data of 75 NSCLC patients with T2DM from January 2008 to December 2011 were collected and analyzed retrospectively. Patients were divided into 2 groups: metformin exposure group (n = 27) and non-metformin group (patients using other hypoglycemic agents or no drug for controlling n = 48). Univariate and multivariate analyses were performed to assess the association of metformin usage with overall survival (OS).Mean follow-up time was 58.7 months. The mean survival time was 36.74 months in the metformin group and 40.21 months in the non-metformin group. There was no significant difference in survival time between the 2 groups (P = .661). After adjusting gender, age, smoking status, tumor stage, tumor histology, and differentiation, multivariate analysis showed that metformin was not associated with the OS in NSCLC patients treated with concurrent platinum-based chemotherapy (hazard ratio: 1.071, 95% confidence interval: 0.577-1.986, P = .828).Our results indicated that metformin exposure had no significant effect on OS in NSCLC patients treated with platinum-based chemotherapy. Further studies are warranted to evaluate whether metformin could affect the survival of NSCLC patients treated with platinum-based chemotherapy.

Novel application of metformin combined with targeted drugs on anticancer treatment

The success of targeted drug therapies for treating cancer patients has attracted broad attention both in the academic community and social society. However, rapidly developed acquired resistance is becoming a newly recognized major challenge to the continuing efficiency of these therapies. Metformin is a well‐known natural compound with low toxicity derived from the plant French lilac. Our previous work has highlighted research progress of the combination of clinically applied chemotherapies and metformin by different mechanisms. We have also launched a study to combine metformin with the small molecule targeted drug gefitinib to treat bladder cancer using intravesical administration. Thus, in this minireview, we summarize recent achievements combining metformin with various targeted therapies. This work directs the potential clinical future by selecting available cancer patients and providing precise medicine by the combination of metformin and targeted drugs to overcome resistance and enhance therapeutic efficacies.

EMT: A mechanism for escape from EGFR-targeted therapy in lung cancer

Epithelial mesenchymal transition (EMT) is a reversible developmental genetic programme of transdifferentiation of polarised epithelial cells to mesenchymal cells. In cancer, EMT is an important factor of tumour cell plasticity and has received increasing attention for its role in the resistance to conventional and targeted therapies. In this paper we provide an overview of EMT in human malignancies, and discuss contribution of EMT to the development of the resistance to Epidermal Growth Factor Receptor (EGFR)-targeted therapies in non-small cell lung cancer (NSCLC). Patients with the tumours bearing specific mutations in EGFR have a good clinical response to selective EGFR inhibitors, but the resistance inevitably develops. Several mechanisms responsible for the resistance include secondary mutations in the EGFR gene, genetic or non-mutational activation of alternative survival pathways, transdifferentiation of NSCLC to the small cell lung cancer histotype, or formation of resistant tumours with mesenchymal characteristics. Mechanistically, application of an EGFR inhibitor does not kill all cancer cells; some cells survive the exposure to a drug, and undergo genetic evolution towards resistance. Here, we present a theory that these quiescent or slow-proliferating drug-tolerant cell populations, or so-called "persisters", are generated via EMT pathways. We review the EMT-activated mechanisms of cell survival in NSCLC, which include activation of ABC transporters and EMT-associated receptor tyrosine kinase AXL, immune evasion, and epigenetic reprogramming. We propose that therapeutic inhibition of these pathways would eliminate pools of persister cells and prevent or delay cancer recurrence when applied in combination with the agents targeting EGFR.

Metformin synergistically enhances the antitumor activity of the third-generation EGFR-TKI CO-1686 in lung cancer cells through suppressing NF-κB signaling

PURPOSE

Third-generation irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), rociletinib (CO-1686), is great efficacy against EGFR-mutated patients bearing the T790M resistance mutation. However, acquired resistance may emerge. There is a need to characterize acquired resistance mechanism(s) and to devise ways to overcome CO-1686 resistance.

EXPERIMENTAL DESIGN

MTT assay, ki67 incorporation assay, transwell assay and TUNEL assay were employed to analyze the effects of metformin to reverse CO-1686 resistance in vitro. The NF-κB activity was measured by the antibody of p50, p65, p-IKBɑ, and p-IKKɑ/β. Western blotting was used to analyze the proteins in cells.

RESULTS

We have established CO-1686-resistant cell lines of PC-9GRCOR and H1975COR from two parental cell lines of PC-9GR and H1975 by long-term exposure to increasing doses of CO-1686. Compared with the parental cells, PC-9GRCOR cells and H1975COR cells showed 90-folds and 20-folds higher resistance to CO-1686, respectively. Critically, we showed that the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling molecular proteins subunits of p50, p65 and its inhibitor proteins of IKBɑ, IKKɑ/β in phosphorylation levels in resistant cells were higher than parental cells. Accordingly, inhibition of NF-κB activity used TPCA-1 effective in decreasing viability and inducing apoptosis of resistant cells. Moreover, metformin overcame the acquired resistance to CO-1686 by reducing cell proliferation and invasion. Metformin combined with CO-1686 synergistically inhibited the p-IKBɑ, p-IKKɑ/β, p50, and p65.

CONCLUSIONS

NF-κB signaling activation induced acquired resistance to CO-1686. Metformin sensitized resistant cells to CO-1686 via inhibiting NF-κB signaling.

Metformin and blood cancers

Type 2 diabetes mellitus and cancer are correlated with changes in insulin signaling, a pathway that is frequently upregulated in neoplastic tissue but impaired in tissues that are classically targeted by insulin in type 2 diabetes mellitus. Many antidiabetes treatments, particularly metformin, enhance insulin signaling, but this pathway can be inhibited by specific cancer treatments. The modulation of cancer growth by metformin and of insulin sensitivity by anticancer drugs is so common that this phenomenon is being studied in hundreds of clinical trials on cancer. Many meta-analyses have consistently shown a moderate but direct effect of body mass index on the incidence of multiple myeloma and lymphoma and the elevated risk of leukemia in adults. Moreover, new epidemiological and preclinical studies indicate metformin as a therapeutic agent in patients with leukemia, lymphomas, and multiple myeloma. In this article, we review current findings on the anticancer activities of metformin and the underlying mechanisms from preclinical and ongoing studies in hematologic malignancies.

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.

Metformin use and survival of lung cancer patients: Meta-analysis findings

Previous studies on the association between metformin use and lung cancer survival have yielded mixed results. We aimed to perform a metaanalysis to assess the association with all available studies. Relevant studies were identified by searching PubMed and EMBASE to July 2016. We calculated the summary hazard ratios (HRs) and 95% confidence intervals (CIs) using randomeffects models. Twelve cohort studies involving 124,533 participants were included in this study. The results showed that metformin use was not associated with the overall survival of lung cancer patients (HR = 0.79, 95% CI: 0.62-1.02). In the subgroup analyses by country or subtype of lung cancer, although a beneficial effect of metformin use on overall survival was found in patients with smallcell lung cancer or in lung patients from China, it may be inappropriate draw a final conclusion considering small sample size, low study quality, and the limited number of studies in the subgroups. Further analyses found that metformin use after diagnosis showed a beneficial effect on both over survival (HR = 0.79, 95% CI: 0.72-0.87) and progressionfree survival (PFS; HR = 0.62, 95% CI: 0.39-0.96) of lung cancer patients. In conclusion, metformin use after diagnosis is associated with improved overall survival and PFS of lung cancer patients. Nevertheless, this effect of metformin use is needed for further assessment.

The prognostic value of metformin for advanced non-small cell lung cancer: a systematic review and meta-analysis

Background

The prognostic value of Metformin for concurrent non-small cell lung cancer (NSCLC) has been controversial in previous individual studies and meta-analyses. In order to further investigate the value of this medication, we conducted a systematic review and meta-analysis for patients with advanced or inoperable NSCLC.

Methods

We searched articles from PubMed, Scopus and Web of Science databases; the time interval was from the inception date of the databases to 1 September 2017. Inclusion criteria for eligible studies were: advanced or inoperable NSCLC; Metformin as an experimental group, and non-Metformin usage as a control group; progression-free survival (PFS) or overall survival (OS) as the outcome, with available hazard ratio (HR). Data synthesis was conducted based on the random-effect model.

Results

From a total of 97 articles in databases, we included seven eligible studies. Among them, only one study compared Metformin usage and non-Metformin usage for NSCLC patients who didn't have diabetes mellitus (DM): no significant difference was found in either OS or PFS. The remaining six studies compared Metformin usage and non-Metformin usage for patients with concurrent NSCLC and DM: according to meta-analysis, significantly prolonged OS was found in Metformin usage rather than non-Metformin usage [pooled HR =0.87 (0.77-0.99), P=0.04]; no significant difference was indicated in PFS [pooled HR =0.85 (0.67-1.07), P=0.16]. In subgroup analysis, among patients with late-stage NSCLC and DM, significant difference was found, regardless of OS [pooled HR =0.81 (0.70-0.94), P<0.01] or PFS [pooled HR =0.71 (0.58-0.88), P<0.01]. However, among patients with local advanced NSCLC and DM, there was no significant difference [OS: pooled HR =1.05 (0.79-1.40), P=0.74; PFS: pooled HR =0.94 (0.68-1.32), P=0.74].

Conclusions

The prognostic value of Metformin for concurrent late-stage NSCLC and DM was demonstrated. It deserves further confirmation and explanation.

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.

Effect of hypoglycemic agents on survival outcomes of lung cancer patients with diabetes mellitus: A meta-analysis

BACKGROUND

To assess the association between hypoglycemic agents and prognosis of lung cancer patients with diabetes.

METHODS

A comprehensive literature search was performed in PubMed, Web of Science, Embase, and Cochrane Library until May 2017. The search yielded 2593 unique citations, of which 18 articles met inclusion criteria. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated by a fixed-effects or random-effects model.

RESULTS

The pooled HRs favoring metformin users were 0.77 for overall survival (OS) (n = 15, 95% CI: 0.68-0.86) and 0.50 for disease-free survival (n = 5, 95% CI: 0.39-0.64). One study assessed the relationship between metformin and cancer-specific survival (CSS), reporting no significant results. No significant association between insulin and OS (n = 2, HR: 0.95, 95% CI: 0.79-1.13) or CSS (n = 2, HR: 1.03, 95% CI: 0.76-1.41) was noted. One study evaluated association of sulfonylureas with lung cancer survival and reported no clinical benefit (HR: 1.10, 95% CI: 0.87-1.40). One study reported no association of thiazolidinediones with lung cancer survival (HR: 1.04, 95% CI: 0.65-1.66).

CONCLUSIONS

This meta-analysis demonstrated that metformin exposure might improve survival outcomes in lung cancer patients with diabetes.