Cyclosporine A sensitizes human non-small cell lung cancer cells to gefitinib through inhibition of STAT3.

The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have dramatically prolonged the overall survival of non-small cell lung cancer (NSCLC) patients with EGFR-activating mutation, but the presence of primary or acquired resistance eventually leads to therapeutic failure. Thus, how to improve the efficacy and reverse the resistance to EGFR-TKIs remains a significant challenge. In this study, we found that CsA significantly augmented the anti-cancer effect of gefitinib in EGFR-TKI-sensitive and -resistant NSCLC cells. Mechanistically, CsA promoted gefitinib-induced apoptosis through inhibition of the STAT3 pathway. Similar with the function of CsA, siRNAs against STAT3 also enhanced gefitinib-induced apoptosis in multiple lung cancer cells. Xenograft studies further demonstrated that CsA promoted the anti-cancer activity of gefitinib on lung cancer cells through inhibition of STAT3. Moreover, NSCLC patients with high levels of phosphorylated STAT3 (Y705) showed a significantly poorer therapeutic response to EGFR-TKIs. This study provides preclinical evidence that the combination of CsA or a STAT3 inhibitor with EGFR-TKIs is a promising approach to improve the efficacy of EGFR-TKIs for the treatment of patients with advanced NSCLC.

Shou J ，You L ，Yao J ，Xie J ，Jing J ，Jing Z ，Jiang L ，Sui X ，Pan H ，Han W ... -  《-》

244-MPT overcomes gefitinib resistance in non-small cell lung cancer cells.

Zhang Y ，Yao K ，Shi C ，Jiang Y ，Liu K ，Zhao S ，Chen H ，Reddy K ，Zhang C ，Chang X ，Ryu J ，Bode AM ，Dong Z ，Dong Z ... -  《Oncotarget》

A novel STAT3 inhibitor W2014-S regresses human non-small cell lung cancer xenografts and sensitizes EGFR-TKI acquired resistance.

Constitutive activation of signal transducer and activator of transcription 3 (STAT3) is a common feature in human non-small cell lung cancer (NSCLC). STAT3 plays an important role in cancer progression as a driver oncogene and acquired resistance of targeted therapies as an alternatively activated pathway. W2014-S with pharmacophore structure of imidazopyridine, which was firstly reported to be utilized in STAT3 inhibitor discovery, was screened out as a potent STAT3 inhibitor from a library of small molecules. The aim of this study is to investigate the antitumor activities and mechanisms of W2014-S in NSCLC and effect on epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) resistance in vitro and in vivo. Methods: SPR analysis, Co-immunoprecipitation, confocal microscope imaging, and luciferase report gene assays were utilized to determine the mechanisms. Cell viability, colonial survival, wound healing, cell invasion assay, human cancer cell xenografts and PDX tumor xenografts were used to determine antitumor activities. Results: W2014-S disrupted STAT3 dimerization and selectively inhibited aberrant STAT3 signaling in NSCLC cell line. W2014-S strongly suppressed proliferation, survival, migration and invasion of lung cancer cells with aberrant STAT3 activation and inhibited the growth of human NSCLC cell xenografts and PDX tumor xenografts in mouse model. Furthermore, W2014-S significantly sensitized resistant NSCLC cell line to gefitinib and erlotinib in vitro and enhances the anti-tumor effect of gefitinib in TKI-resistant lung cancer xenografts in vivo. Conclusions: Our study has provided a novel STAT3 inhibitor with significant anti-tumor activities in NSCLC and suggests that combination of STAT3 inhibitor such as W2014-S with gefitinib could serve as a promising strategy to overcome EGFR-TKIs acquired resistance in NSCLC patients.

Zheng Q ，Dong H ，Mo J ，Zhang Y ，Huang J ，Ouyang S ，Shi S ，Zhu K ，Qu X ，Hu W ，Liu P ，Wang Y ，Zhang X ... -  《Theranostics》

Lymecycline reverses acquired EGFR-TKI resistance in non-small-cell lung cancer by targeting GRB2.

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) were first-line treatments for NSCLC patients with EGFR-mutations. However, about 30 % of responders relapsed within six months because of acquired resistance. In this study, we used Connectivity Map (CMap) to discover a drug capable of reversing acquired EGFR-TKIs resistance. To investigate Lymecycline's ability to reverse acquired EGFR-TKIs resistance, two Icotinib resistant cell lines were constructed. Lymecycline's ability to suppress the proliferation of Icotinib resistant cells in vitro and in vivo was then evaluated. Molecular targets were predicted using network pharmacology and used to identify the molecular mechanism. Growth factor receptor-bound protein 2 (GRB2) is an EGFR-binding adaptor protein essential for EGFR phosphorylation and regulation of AKT/ERK/STAT3 signaling pathways. Lymecycline targeted GRB2 and inhibited the resistance of the cell cycle to EGFR-TKI, arresting disease progression and inducing apoptosis in cancer cells. Combined Lymecycline and Icotinib treatment produced a synergistic effect and induced apoptosis in HCC827R5 and PC9R10 cells. Cell proliferation in resistant cancer cells was significantly inhibited by the combined Lymecycline and Icotinib treatment in mouse models. Lymecycline inhibited the resistance of the cell cycle to EGFR-TKI and induced apoptosis in NSCLC by inhibiting EGFR phosphorylation and GRB2-mediated AKT/ERK/STAT3 signaling pathways. This provided strong support that Lymecycline when combined with EGFR targeting drugs, enhanced the efficacy of treatments for drug-resistant NSCLC.

Chen Y ，Wu J ，Yan H ，Cheng Y ，Wang Y ，Yang Y ，Deng M ，Che X ，Hou K ，Qu X ，Zou D ，Liu Y ，Zhang Y ，Hu X ... -  《-》

Apatinib enhances antitumour activity of EGFR-TKIs in non-small cell lung cancer with EGFR-TKI resistance.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)-rechallenged therapy for EGFR-mutant non-small cell lung cancer (NSCLC) patients who acquired resistance showed moderate efficacy. Considering the high interrelation between EGFR and vascular endothelial growth factor/vascular endothelial growth factor receptor (VEGF/VEGFR) pathways, we firstly evaluated EGFR-TKI combined with apatinib (a highly selective VEGFR2 inhibitor) in EGFR-TKI-resistant model and patients. Effects of apatinib, gefitinib and gefitinib plus apatinib were assessed on four NSCLC cell lines (A549 with wild-type EGFR, H1975 harbouring L858R and T790M, H1650 and HCC827 harbouring E746_A750 deletion) and xenograft model of acquired resistance that was established by injecting H1975 cells. Furthermore, we retrospectively evaluated EGFR-TKI rechallenge with apatinib in 16 patients. Gefitinib plus apatinib strengthened the effect of gefitinib and apatinib alone on the four NSCLC cell lines, and H1975 was the most susceptible one. Co-administration delayed the tumour growth than mono-therapy in the xenograft model and had better effect on inhibiting the activation of EGFR and VEGFR2 and expression of CD31 (an angiogenesis marker) and vascular endothelial growth factor A (an important pro-angiogenesis factor in the tumour microenvironment). Changes in protein expression of protein kinase B/mammalian target of rapamycin and extracellular signal-regulated kinase pathways demonstrated the potent inhibitory effect on the pro-survival signalling pathways by combined therapy. EGFR-TKI rechallenge with apatinib achieved a median progression-free survival of 4.60 months (95% confidence interval, 2.23-12.52 months) in the patients. Apatinib significantly potentiated the antitumour effect of gefitinib in NSCLC with T790M-related EGFR-TKI resistance both in vivo and vitro. EGFR-TKI rechallenge with apatinib might represent a new option for NSCLC with T790M or unknown resistance mechanism.

Li F ，Zhu T ，Cao B ，Wang J ，Liang L ... -  《-》