PKM2/PDK1 dual-targeted shikonin derivatives restore the sensitivity of EGFR-mutated NSCLC cells to gefitinib by remodeling glucose metabolism

Pyruvate kinase 2 (PKM2) and pyruvate dehydrogenase kinase 1 (PDK1) are two key enzymes in tumor glucose metabolism pathway that not only promote tumor growth and proliferation through accelerating aerobic glycolysis, but also contribute to drug resistance of non-small cell lung cancer (NSCLC). Considering that targeting PKM2 or PDK1 alone seems insufficient to remodel abnormal glucose metabolism to achieve significant antitumor activity, we proposed a "two-step approach" that regulates PKM2 and PDK1 synchronously. Firstly, we found that the combination of ML265 (PKM2 activator) and AZD7545 (PDK1 inhibitor) could synergistically inhibit proliferation and induce apoptosis in H1299 cells. Base on this, we designed a series of novel shikonin (SK) thioether derivatives as PKM2/PDK1 dual-target agents, among which the most potent compound E5 featuring a 2-methyl substitution on the benzene ring exerted significantly increased inhibitory activity toward EGFR mutant NSCLC cell H1975 (IC₅₀ = 1.51 μmol/L), which was 3 and 17-fold more active than the lead compound SK (IC₅₀ = 4.56 μmol/L) and the positive control gefitinib (IC₅₀ = 25.56 μmol/L), respectively. Additionally, E5 also showed good anti-tumor activity in xenografted mouse models, with significantly lower toxicity side effects than SK. Moreover, E5 also inhibited the entry of PKM2 into nucleus to regulate the transcriptional activation of oncogenes, thus restoring the sensitivity of H1975 cell to gefitinib. Collectively, these data demonstrate that E5, a dual inhibitor of PKM2/PDK1, may be a promising adjunct to gefitinib in the treatment of EGFR-TKIs resistant NSCLC, deserving further investigation.

Anlotinib combined with osimertinib reverses acquired osimertinib resistance in NSCLC by targeting the c-MET/MYC/AXL axis

Favorable clinical evidence suggests that the next trend in new treatments for advanced non-small cell lung cancer (NSCLC) will be combination therapies. However, inevitable epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) resistance greatly limits the clinical efficacy of patients carrying EGFR-activating mutants. In this study, we found a patient with clinical osimertinib resistance who regained a positive response after osimertinib plus anlotinib treatment. Two osimertinib-resistant cell lines were constructed, and AXL conferred resistance to osimertinib in NSCLC cell lines. The combined effects of anlotinib and osimertinib restored sensitivity to osimertinib in two osimertinib-resistant NSCLC cell lines and in xenografts. Moreover, anlotinib inhibits the phosphorylation of AXL in both resistant cell lines. Mechanistically, we confirmed that MYC binds to the promoter of AXL to promote its transcription in NSCLC cells, and we demonstrated that anlotinib combined with osimertinib treatment enhances the anti-tumor effect by inactivating the c-MET/MYC/AXL axis to reverse osimertinib resistance in NSCLC. In conclusion, our results provide strong support that this combination therapy may be effective in enhancing the efficacy of treatments in patients with advanced NSCLC.

Acquired resistance to EGFR-TKIs in NSCLC mediates epigenetic downregulation of MUC17 by facilitating NF-κB activity via UHRF1/DNMT1 complex

Treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has brought significant benefits to non-small cell lung cancer (NSCLC) patients with EGFR mutations. However, most patients eventually develop acquired resistance after treatment. This study investigated the epigenetic effects of mucin 17 (MUC17) in acquired drug-resistant cells of EGFR-TKIs. We found that GR/OR (gefitinib/osimertinib-resistance) cells enhance genome-wide DNA hypermethylation, mainly in 5-UTR associated with multiple oncogenic pathways, in which GR/OR cells exerted a pro-oncogenic effect by downregulating mucin 17 (MUC17) expression in a dose- and time-dependent manner. Gefitinib/osimertinib acquired resistance mediated down-regulation of MUC17 by promoting DNMT1/UHRF1 complex-dependent promoter methylation, thereby activating NF-κB activity. MUC17 increased the generation of IκB-α and inhibit NF-κB activity by promoting the expression of MZF1. In vivo results also showed that DNMT1 inhibitor (5-Aza) in combination with gefitinib/osimertinib restored sensitivity to OR/GR cells. Acquired drug resistance of gefitinib/osimertinib promoted UHRF1/DNMT1 complex to inhibit the expression of MUC17. MUC17 in GR/OR cells may act as an epigenetic sensor for biomonitoring the resistance to EGFR-TKIs.

Impact of TP53 Mutations on EGFR-Tyrosine Kinase Inhibitor Efficacy and Potential Treatment Strategy

BACKGROUND

We investigated the impact of factors that influence TP53 mutations on the efficacy of EGFR-tyrosine kinase inhibitors and potential treatment strategies.

MATERIALS AND METHODS

Tumor samples were collected to screen gene mutations by next-generation sequencing, as well as the patients' baseline characteristics. The overall response to treatment with TKIs was evaluated based on interval computed tomography scans at each follow-up time point. A Fisher's exact test and log-rank test were used to determine the statistical differences in this study.

RESULTS

A total of 1134 clinical samples were collected from NSCLC patients, and TP53^mut was identified in 644 cases and EGFR^mut in 622 cases. A low frequency of TP53^mut or more than 50% EGFR co-mutation rate were related to the prognosis of TKI-treated patients. In addition, TP53^mut in the region outside of the DB domain had the strongest correlation with TKI resistance, whereas various types of mutations in the DB domain only had an impact on PFS. A grouping study of EGFR-TKI-based treatment revealed that EGFR-TKIs with chemotherapy were associated with more significant survival benefits for patients with prognostic TP53^mut, whereas EGFR-TKI therapy was favorable for TP53^wt patients. Furthermore, TP53^mut could shorten the time to the relapse of postoperative patients, who will also likely respond well to EGFR-TKIs with chemotherapy.

CONCLUSION

Various characteristics of TP53^mut affect the prognosis of TKI-treated patients to varying degrees. EGFR-TKIs with chemotherapy were benefit for patients' survival with prognostic TP53^mut, which provides an important reference for treatment management of EGFR^mut patients.

[Advances in ICIs Therapy after TKIs Resistance in Patients with EGFR Mutant NSCLC: A Review]

The follow-up treatment of patients with advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutation after drug resistance to EGFR-tyrosine kinase inhibitors (TKIs) have become a hotspot and difficulty at present. Immune checkpoint inhibitors (ICIs) therapy is a new and important choice for these patients, but many studies have shown unsatisfactory efficacy. However, some domestic and foreign studies have shown that ICIs combination therapy is still effective in some patients with positive driver genes and drug resistance after targeted therapy. So, in the era of immunotherapy, what are the differences in the efficacy of different combination immunotherapy strategies for different patients? What are the factors that affect efficacy? What are the interrelationships between these factors and other immunotherapy efficacy prediction biomarkers? All these problems have broad and important research value.
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Cholesterol promotes EGFR-TKIs resistance in NSCLC by inducing EGFR/Src/Erk/SP1 signaling-mediated ERRα re-expression

BACKGROUND

The use of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) brings remarkable benefits for the survival of patients with advanced NSCLC harboring EGFR mutations. Unfortunately, acquired resistance seems to be inevitable and limits the application of EGFR-TKIs in clinical practice. This study reported a common molecular mechanism sustaining resistance and potential treatment options to overcome EGFR-TKIs resistance.

METHODS

EGFR-TKIs resistant NSCLC cells were established and confirmed by MTT assay. Cholesterol content was detected and the promotional function of cholesterol on NSCLC growth was determined in vivo. Then, we identified ERRα expression as the downstream factor of cholesterol-mediated drug resistance. To dissect the regulatory mechanism, we conducted experiments, including immunofluorescence, co-immunoprecipitation, luciferase reporter assay and chromatin immunoprecipitation assay.

RESULTS

Long-term exposure to EGFR-TKIs generate drug resistance with the characteristic of cholesterol accumulation in lipid rafts, which promotes EGFR and Src to interact and lead EGFR/Src/Erk signaling reactivation-mediated SP1 nuclear translocation and ERRα re-expression. Further investigation identifies ERRα as a target gene of SP1. Functionally, re-expression of ERRα sustains cell proliferation by regulating ROS detoxification process. Lovastatin, a drug used to decrease cholesterol level, and XCT790, an inverse agonist of ERRα, overcome gefitinib and osimertinib resistance both in vitro and in vivo.

CONCLUSIONS

Our study indicates that cholesterol/EGFR/Src/Erk/SP1 axis-induced ERRα re-expression promotes survival of gefitinib and osimertinib-resistant cancer cells. Besides, we demonstrate the potential of lowing cholesterol and downregulation of ERRα as effective adjuvant treatment of NSCLC.

Tumor-derived exosomal circRNA_102481 contributes to EGFR-TKIs resistance via the miR-30a-5p/ROR1 axis in non-small cell lung cancer

Exosomes are messengers for intercellular communication and signal transduction. Circular RNA (circRNA) abnormal expression and regulation are involved in the occurrence and development of a variety of tumors. In the present study, exosomes in the serum of five patients with non-small cell lung cancer (NSCLC) were isolated before and after EGFR-TKIs resistance, and the circRNA expression profile was screened using a circRNA microarray. The effects of the exosome circRNA_102481 on cell proliferation and apoptosis were analyzed. The interaction between miR-30a-5p and circRNA_102481 or ROR1 was predicted by starBase software, and was confirmed by RNA pull-down and dual-luciferase reporter assays. The results showed that exosomes containing circRNA_102481 were significantly up-regulated in NSCLC with EGFR-TKIs resistance (p<0.05), and that circRNA_102481 was mainly secreted by EGFR-TKIs resistance cell via exosomes (p<0.05). Both circRNA_102481 silencing and si-circRNA_102481 transported by exosomes could inhibit EGFR-TKIs resistance cell proliferation and promote cell apoptosis and circRNA_102481 overexpression could promote EGFR-TKIs sensitive cell proliferation and inhibit cell apoptosis in vitro (p<0.05). CircRNA_102481 served as a miR-30a-5p sponge to regulate ROR1 expression (p<0.05). Furthermore, the expression of circRNA_102481 in exosomes was associated with TNM stage, tumor differentiation status, brain metastasis, and PFS and OS duration. Therefore, it was concluded that tumor-derived exosomal circRNA_ 102481 could contribute to EGFR-TKIs resistance via the microRNA-30a-5p/ROR1 axis in NSCLC. Exosomal circRNA_102481 may serve as a novel diagnostic biomarker and a therapeutic target for EGFR-TKIs resistance in NSCLC.

NRF2-GPX4/SOD2 axis imparts resistance to EGFR-tyrosine kinase inhibitors in non-small-cell lung cancer cells

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have achieved satisfactory clinical effects in the therapy of non-small cell lung cancer (NSCLC), but acquired resistance limits their clinical application. NRF2 has been shown to enhance the resistance to apoptosis induced by radiotherapy and some chemotherapy. In this study, we investigated the role of NRF2 in resistance to EGFR-TKIs. We showed that NRF2 protein levels were markedly increased in a panel of EGFR-TKI-resistant NSCLC cell lines due to slow degradation of NRF2 protein. NRF2 knockdown overcame the resistance to EGFR-TKIs in HCC827ER and HCC827GR cells. Furthermore, we demonstrated that NRF2 imparted EGFR-TKIs resistance in HCC827 cells via upregulation of GPX4 and SOD2, and suppression of GPX4 and SOD2 reversed resistance to EGFR-TKIs. Thus, we conclude that targeting NRF2-GPX4/SOD2 pathway is a potential strategy for overcoming resistance to EGFR-TKIs.

Statins use and its impact in EGFR-TKIs resistance to prolong the survival of lung cancer patients: A Cancer registry cohort study in Taiwan

Statins have been shown to be a beneficial treatment as chemotherapy and target therapy for lung cancer. This study aimed to investigate the effectiveness of statins in combination with epidermal growth factor receptor-tyrosine kinase inhibitor therapy for the resistance and mortality of lung cancer patients. A population-based cohort study was conducted using the Taiwan Cancer Registry database. From January 1, 2007, to December 31, 2012, in total 792 non-statins and 41 statins users who had undergone EGFR-TKIs treatment were included in this study. All patients were monitored until the event of death or when changed to another therapy. Kaplan-Meier estimators and Cox proportional hazards regression models were used to calculate overall survival. We found that the mortality was significantly lower in patients in the statins group compared with patients in the non-statins group (4-y cumulative mortality, 77.3%; 95% confidence interval (CI), 36.6%-81.4% vs. 85.5%; 95% CI, 78.5%-98%; P = .004). Statin use was associated with a reduced risk of death in patients the group who had tumor sizes <3 cm (hazard ratio [HR], 0.51, 95% CI, 0.29-0.89) and for patients in the group who had CCI scores <3 (HR, 0.6; 95% CI, 0.41-0.88; P = .009). In our study, statins were found to be associated with prolonged survival time in patients with lung cancer who were treated with EGFR-TKIs and played a synergistic anticancer role.

Nanomodified strategies to overcome EGFR-tyrosine kinase inhibitors resistance in non-small cell lung cancer

Lung cancer is the primary cause of cancer-related death worldwide. 85%-90% of cases are non-small cell lung cancer (NSCLC) which characteristically exhibits altered epidermal growth factor receptor (EGFR) signaling is a major driver pathway. Unfortunately, therapeutic outcomes in treating NSCLC are compromised by the emergence of drug resistance in response to EGFR-tyrosine kinase inhibitor (TKI) targeted therapy due to the acquired resistance mutation EGFR T790M or activation of alternative pathways. There is current need for a new generation of TKIs to be developed to treat EGFR-TKI-resistant NSCLC. To overcome the above problems and improve clinical efficacy, nanotechnology with targeting abilities and sustained release has been proposed for EGFR-TKI-resistant NSCLC treatment and has already achieved success in in vitro or in vivo models. In this review, we summarize and illustrate representative nano-formulations targeting EGFR-TKI-resistant NSCLC. The described advances may pave the way to better understanding and design of nanocarriers and multifunctional nanosystems for efficient treatment for drug resistant NSCLC.

EGFR-TKI resistance promotes immune escape in lung cancer via increased PD-L1 expression

BACKGROUND

The ATLANTIC trial reported that higher PD-L1 expression in tumors was involved in a higher objective response in patients with EGFR⁺/ALK⁺ non-small cell lung cancer (NSCLC), indicating the possibility of anti-PD-1/PD-L1 therapy as a third-line (or later) treatment for advanced NSCLC. Therefore, the determination of status and regulatory mechanisms of PD-L1 in EGFR mutant NSCLC before and after acquired EGFR-TKIs resistance are meaningful.

METHODS

The correlation among PD-L1, c-MET, and HGF was analyzed based on TCGA datasheets and paired NSCLC specimens before and after acquired EGFR-TKI resistance. EGFR-TKI resistant NSCLC cells with three well-known mechanisms, c-MET amplification, hepatocyte growth factor (HGF), and EGFR-T790M, were investigated to determinate PD-L1 expression status and immune escape ability. PD-L1-deleted EGFR-TKIs sensitive and resistant cells were used to evaluate the immune escape ability of tumors in mice xenograft models.

RESULTS

Positive correlations were found among PD-L1, c-MET, and HGF, based on TCGA datasheets and paired NSCLC specimens. Moreover, the above three resistant mechanisms increased PD-L1 expression and attenuated activation and cytotoxicity of lymphocytes in vitro and in vivo, and downregulation of PD-L1 partially restored the cytotoxicity of lymphocytes. Both MAPK and PI3K pathways were involved in the three types of resistance mechanism-induced PD-L1 overexpression, whereas the NF-kappa B pathway was only involved in T790M-induced PD-L1 expression.

CONCLUSIONS

HGF, MET-amplification, and EGFR-T790M upregulate PD-L1 expression in NSCLC and promote the immune escape of tumor cells through different mechanisms.

[Research Progress of the Role of EMT in EGFR-TKIs Resistance of Non-small Cell Lung Cancer]

肺癌是全世界范围内发病率和死亡率最高的恶性肿瘤之一，其中大约80%是非小细胞肺癌（non-small cell lung cancer, NSCLC）。目前分子靶向治疗已成为NSCLC的一线治疗方法，其中表皮生长因子受体-酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitors, EGFR-TKIs）越来越多地应用于临床治疗，但EGFR-TKI的获得性耐药成为制约EGFR-TKI继续使用的瓶颈。上皮间质转化（epithelial-mesenchymal transition, EMT）是上皮细胞转化为间质表型细胞的生物学现象，可促进肺癌转移、侵袭以及肿瘤细胞获得干性。此外，EMT也是引起NSCLC对EGFR-TKIs耐药的原因之一。有研究发现，逆转NSCLC细胞的间质表型，耐药的细胞能恢复对吉非替尼的敏感性，提示靶向EMT的治疗，或能阻止甚至是逆转NSCLC细胞对EGFR-TKIs的耐药，本文对EMT在NSCLC EGFR-TKIs耐药中的研究进展作一综述。

USP22 promotes resistance to EGFR-TKIs by preventing ubiquitination-mediated EGFR degradation in EGFR-mutant lung adenocarcinoma

As a newly discovered deubiquitinating enzyme, ubiquitin-specific protease 22 (USP22) is predictive of therapeutic outcomes in individual cancer patients. However, its clinical effects on malignancy and its roles in conferring resistance to EGFR-TKIs (epidermal growth factor receptor-tyrosine kinase inhibitors) in lung adenocarcinoma (ADC) remain largely unknown. Here, we showed that USP22 promotes cell proliferation, migration and invasion, and contributes to resistance to EGFR-TKIs in EGFR mutant lung ADC cells. Mechanistically, USP22 deubiquitinates EGFR localized on late endosomes, prevents ubiquitination mediated EGFR degradation and enhances recycling of EGFR after EGF stimulation. Additionally, USP22 sustained the activation of multiple EGFR downstream signaling pathways, including STAT3, AKT/mTOR and MEK/ERK pathways, in lung ADC cell lines H1975 and PC9. Furthermore, USP22 stabilizes EGFR protein expression, which correlates with USP22 expression in EGFR-mutant lung ADC patient samples. We are the first to demonstrate that silencing USP22 counteracts EGFR-TKIs resistance both in vitro and in vivo. We propose USP22 as a potential therapeutic target for EGFR-TKIs-resistant lung ADC.

Cancer-associated fibroblasts promote epithelial-mesenchymal transition and EGFR-TKI resistance of non-small cell lung cancers via HGF/IGF-1/ANXA2 signaling

The involvement of the tumor stromal cells in acquired resistance of non-small cell lung cancers (NSCLCs) to tyrosine kinase inhibitors (TKIs) has previously been reported, but the precise mechanism remains unclear. In the present study, we investigated the role and mechanism underlying Cancer-associated fibroblasts (CAFs) in TKI resistance of NSCLCs. In vitro and in vivo experiments showed that HCC827 and PC9 cells, non-small cell lung cancer cells with EGFR-activating mutations, became resistant to the EGFR-TKI gefitinib when cultured with CAFs isolated from NSCLC tissues. Moreover, we showed that CAFs could induce epithelial-mesenchymal transition (EMT) phenotype of HCC827 and PC9 cells, with an associated change in the expression of epithelial to mesenchymal transition markers. Using proteomics-based method, we identified that CAFs significantly increased the expression of the Annexin A2 (ANXA2). More importantly, knockdown of ANXA2 completely reversed EMT phenotype and gefitinib resistance induced by CAFs. Furthermore, we found that CAFs increased the expression and phosphorylation of ANXA2 by secretion of growth factors HGF and IGF-1 and by activation of the corresponding receptors c-met and IGF-1R. Dual inhibition of HGF/c-met and IGF-1/IGF-1R pathways could significantly suppress ANXA2, and markedly reduced CAFs-induced EMT and gefitinib resistance. Taken together, these findings indicate that CAFs promote EGFR-TKIs resistance through HGF/IGF-1/ANXA2/EMT signaling and may be an ideal therapeutic target in NSCLCs with EGFR-activating mutations.

Epidermal growth factor receptor-mutant lung cancer in Down syndrome: a case presentation and review of the literature

BACKGROUND

Solid tumors have a markedly decreased incidence in individuals with Down syndrome (DS), including lung cancers.

METHODS

The clinical presentation of epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC) in DS was reported and literature on the subject reviewed.

RESULTS

In individuals with DS, the risk of lung cancer appears markedly lower. EGFR mutation and EGFR tyrosine kinase inhibitors (EGFR-TKIs) resistance also exist in DS with lung cancer.

CONCLUSIONS

Clinicians should consider EGFR mutation and EGFR-TKIs resistance in lung cancer patients with DS.