Patient-derived cell-based pharmacogenomic assessment to unveil underlying resistance mechanisms and novel therapeutics for advanced lung cancer

BACKGROUND

A pharmacogenomic platform using patient-derived cells (PDCs) was established to identify the underlying resistance mechanisms and tailored treatment for patients with advanced or refractory lung cancer.

METHODS

Drug sensitivity screening and multi-omics datasets were acquired from lung cancer PDCs (n = 102). Integrative analysis was performed to explore drug candidates according to genetic variants, gene expression, and clinical profiles.

RESULTS

PDCs had genomic characteristics resembled with those of solid lung cancer tissues. PDC molecular subtyping classified patients into four groups: (1) inflammatory, (2) epithelial-to-mesenchymal transition (EMT)-like, (3) stemness, and (4) epithelial growth factor receptor (EGFR)-dominant. EGFR mutations of the EMT-like subtype were associated with a reduced response to EGFR-tyrosine kinase inhibitor therapy. Moreover, although RB1/TP53 mutations were significantly enriched in small-cell lung cancer (SCLC) PDCs, they were also present in non-SCLC PDCs. In contrast to its effect in the cell lines, alpelisib (a PI3K-AKT inhibitor) significantly inhibited both RB1/TP53 expression and SCLC cell growth in our PDC model. Furthermore, cell cycle inhibitors could effectively target SCLC cells. Finally, the upregulation of transforming growth factor-β expression and the YAP/TAZ pathway was observed in osimertinib-resistant PDCs, predisposing them to the EMT-like subtype. Our platform selected XAV939 (a WNT-TNKS-β-catenin inhibitor) for the treatment of osimertinib-resistant PDCs. Using an in vitro model, we further demonstrated that acquisition of osimertinib resistance enhances invasive characteristics and EMT, upregulates the YAP/TAZ-AXL axis, and increases the sensitivity of cancer cells to XAV939.

CONCLUSIONS

Our PDC models recapitulated the molecular characteristics of lung cancer, and pharmacogenomics analysis provided plausible therapeutic candidates.

Mechanisms of Acquired Resistance and Tolerance to EGFR Targeted Therapy in Non-Small Cell Lung Cancer

Non-small cell lung cancers (NSCLC) harboring activating mutations of the epidermal growth factor receptor (EGFR) are treated with specific tyrosine kinase inhibitors (EGFR-TKIs) of this receptor, resulting in clinically responses that can generally last several months. Unfortunately, EGFR-targeted therapy also favors the emergence of drug tolerant or resistant cells, ultimately resulting in tumor relapse. Recently, cellular barcoding strategies have arisen as a powerful tool to investigate the clonal evolution of these subpopulations in response to anti-cancer drugs. In this review, we provide an overview of the currently available treatment options for NSCLC, focusing on EGFR targeted therapy, and discuss the common mechanisms of resistance to EGFR-TKIs. We also review the characteristics of drug-tolerant persister (DTP) cells and the mechanistic basis of drug tolerance in EGFR-mutant NSCLC. Lastly, we address how cellular barcoding can be applied to investigate the response and the behavior of DTP cells upon EGFR-TKI treatment.

Case report: Osimertinib administration during pregnancy in a woman with advanced EGFR-mutant non-small cell lung cancer

Lung cancer (LC) is one of the most common causes of death worldwide. The identification of oncogene-addicted driving mutations suitable for targeted therapy has improved clinical outcomes in advanced diseases. Clinical trials, on the other hand, rarely involve vulnerable groups such as pregnant women. We report a 37-year-old woman with advanced non-small cell lung cancer (NSCLC) harboring an exon 19 deletion of EGFR treated with afatinib. After the initial treatment, the patient achieved a complete response and had an unplanned pregnancy. Targeted therapy was withheld during the first trimester and resumed with osimertinib in the second trimester in which the patient developed oligohydramnios and intrauterine growth restriction (IUGR) of the baby. Osimertinib was delayed at two different times during the third trimester with complete resolution of the oligohydramnios. The baby was born at 37.3 weeks of gestation (WOG) with no signs of congenital disorders. After delivery, the mother restarted osimertinib and maintained a complete response. This case suggests that osimertinib could be an acceptable option for tumor control during pregnancy in EGFR-mutant NSCLC. This information do not replace current recommendations for avoiding pregnancy and promoting contraceptive usage in patients receiving any cancer therapy.

Comparison of the Incidence Rate of Radiation Pneumonitis Observed in Patients with Advanced Lung Adenocarcinoma Treated with Simultaneous Thoracic Radiotherapy and 1G/2G/3G EGFR-TKIs

Purpose

The present study aimed to evaluate the incidence rate of radiation pneumonitis (RP) in patients with advanced lung adenocarcinoma treated with first-generation (1G), second-generation (2G), or third-generation (3G) epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) combined with thoracic radiotherapy (TRT).

Patients and Methods

Patients with advanced lung adenocarcinoma simultaneously treated with 1G/2G/3G EGFR-TKIs and TRT between 2015-2021 at Shandong Cancer Hospital and Institute were screened. The incidence rate of clinical and imaging RP was compared between the three groups.

Results

A total of 200 patients treated with EGFR-TKIs were enrolled in this study, including 100 patients who were treated with 1G EGFR-TKIs, 50 patients who were treated with 2G EGFR-TKIs, and 50 patients who were treated with 3G EGFR-TKIs (patients matched in a 2:1:1 ratio for tumor characteristics). The overall incidence of clinical RP in the 1G, 2G, and 3G EGFR-TKI groups were 29%, 48%, and 28% (p=0.043), respectively, and that of imaging RP were 33%, 58%, and 36% (p=0.010), respectively. The incidence of RP with a clinical grade ≥3 in the three groups were 14%, 28%, and 12% (p=0.055), respectively, and that with an imaging grade ≥3 in the three groups were 11%, 32%, and 10% (p=0.002), respectively. The incidence of clinical RP was higher in the CFRT group than in the SBRT group, with an overall clinical grade of 38% vs 10% (p<0.001) and imaging grade of 46% vs 10% (p<0.001), respectively. In the multivariate analysis, only GTV volume was an independent predictive factor for all risks of clinical and imaging RP. V20 and grouping of 1G/2G/3G EGFR-TKIs were other independent predictive factors for the risk factors of RP for imaging grades.

Conclusion

Compared with 2G EGFR-TKIs combined with TRT, 1G or 3G EGFR-TKIs combined with TRT achieved a lower incidence of RP.

Healthcare coverage affects survival of EGFR-mutant Thai lung cancer patients

Background

Despite significant benefits of epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment in patients with EGFR-mutated NSCLC, access remains limited in Thailand and elsewhere.

Methods

Retrospective analysis of patients with locally advanced/recurrent NSCLC and known EGFR mutation (EGFRm) status treated at Ramathibodi Hospital (2012-2017). Prognostic factors for overall survival (OS), including treatment type and healthcare coverage, were analyzed using Cox regression.

Results

Of 750 patients, 56.3% were EGFRm-positive. After first-line therapy (n=646), 29.4% received no subsequent (second-line) treatment. EGFR-TKI-treated EGFRm-positive patients survived significantly longer than EGFRm-negative patients without EGFR-TKIs (median OS [mOS] 36.4 vs. 11.9 months; hazard ratio HR=0.38 [95%CI 0.32-0.46], P<0.001). Cox regression indicated significantly longer OS in patients with comprehensive healthcare coverage that included reimbursement of EGFR-TKIs, versus basic coverage (mOS 27.2 vs. 18.3 months; adjusted HR=0.73 [95%CI 0.59-0.90]). Compared with best supportive care (BSC; reference), EGFR-TKI-treated patients survived significantly longer (mOS 36.5 months; adjusted HR (aHR)=0.26 [95%CI 0.19-0.34]), and versus chemotherapy alone (14.5 months; aHR=0.60 [95%CI 0.47-0.78]). In EGFRm-positive patients (n=422), relative survival benefit of EGFR-TKI treatment remained highly significant (aHR[EGFR-TKI]=0.19 [95%CI 0.12-0.29]; aHR(chemotherapy only)=0.50 [95%CI 0.30-0.85]; reference:BSC), indicating that healthcare coverage (reimbursement) affected treatment choice and survival.

Conclusion

Our analysis describes EGFRm prevalence and survival benefit of EGFR-TKI therapy for EGFRm-positive NSCLC patients treated from 2012-2017, one of the largest such Thai datasets. Together with research by others, these findings contributed evidence supporting the decision to broaden erlotinib access on healthcare schemes in Thailand from 2021, demonstrating the value of local real-world outcome data for healthcare policy decision-making.

Design and Rationale for a Phase II, Randomized, Open-Label, Two-Cohort Multicenter Interventional Study of Osimertinib with or Without Savolitinib in De Novo MET Aberrant, EGFR-Mutant Patients with Advanced Non-Small-Cell Lung Cancer: The FLOWERS Trial

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutations are well-known genetic alterations in advanced non-small cell lung cancer (NSCLC) which are associated with remarkable survival benefits from first-line treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs). However, around 30% of patients exhibit primary resistance to EGFR-TKIs therapy. Co-existing MET amplification/over-expression has showed shorter time to progression on EGFR-TKI monotherapy. Osimertinib (TAGRISSO, AZD9291) has been recommended in EGFR-mutant advanced NSCLC patients as first-line treatment. Savolitinib (AZD6094, HMPL-504) is a highly selective MET-TKI which has demonstrated anti-tumor activity in various cancers with MET alterations.

METHODS

This FLOWERS study, a phase II, randomized, open-label, 2-cohort multicenter trial aimed to evaluate the efficacy and safety of osimertinib with or without savolitinib as first-line therapy in patients with de novo MET amplified/over-expressed, EGFR-mutant positive, locally advanced or metastatic NSCLC. Approximately 44 patients will be randomized to receive osimertinib (80 mg once daily) monotherapy or osimertinib (80 mg once daily) and savolitinib (300 mg twice daily) combination therapy; patients in osimertinib monotherapy cohort confirmed as MET positive (MET-amplified/over-expressed) after disease progression will have the opportunity to receive the cross-over combination therapy as second-line treatment. Primary endpoint will be objective response rate. Key secondary endpoints will be progression-free survival, duration of response, disease control rate, overall survival, safety and tolerability.

CONCLUSION

The results of the study will provide better perspectives on the efficacy and safety of EGFR-TKI plus MET-TKI combination therapy (osimertinib plus savolitinib) in patients with de novo MET-amplified/over-expressed, EGFR-mutant positive, treatment naïve, advanced NSCLC and offer a meaningful guidance in clinical practice (NCT05163249).

Mutations in the MET tyrosine kinase domain and resistance to tyrosine kinase inhibitors in non-small-cell lung cancer

BACKGROUND

The Mesenchymal epithelial transition factor (MET) gene encodes a receptor tyrosine kinase with pleiotropic functions in cancer. MET exon 14 skipping alterations and high-level MET amplification are oncogenic and targetable genetic changes in patients with non-small-cell lung cancer (NSCLC). Resistance to tyrosine kinase inhibitors (TKIs) has been a major challenge for targeted therapies that impairs their clinical efficacies.

METHODS

Eighty-six NSCLC patients were categorized into three cohorts based on the time of detecting MET tyrosine kinase domain (TKD) mutations (cohort 1: at baseline; cohort 2: after MET-TKI treatment; cohort 3: after EGFR-TKI treatment). Baseline and paired TKI treatment samples were analyzed by targeted next-generation sequencing.

RESULTS

MET TKD mutations were highly prevalent in METex14-positive NSCLC patients after MET-TKI treatment, including L1195V, D1228N/H/Y/E, Y1230C/H/N/S, and a double-mutant within codons D1228 and M1229. Missense mutations in MET TKD were also identified at baseline and in post-EGFR-TKI treatment samples, which showed different distribution patterns than those in post-MET-TKI treatment samples. Remarkably, H1094Y and L1195F, absent from MET-TKI-treated patients, were the predominant type of MET TKD mutations in patients after EGFR-TKI treatment. D1228H, which was not found in treatment-naïve patients, also accounted for 14.3% of all MET TKD mutations in EGFR-TKI-treated samples. Two patients with baseline EGFR-sensitizing mutations who acquired MET-V1092I or MET-H1094Y after first-line EGFR-TKI treatment experienced an overall improvement in their clinical symptoms, followed by targeted therapy with MET-TKIs.

CONCLUSIONS

MET TKD mutations were identified in both baseline and patients treated with TKIs. MET-H1094Y might play an oncogenic role in NSCLC and may confer acquired resistance to EGFR-TKIs. Preliminary data indicates that EGFR-mutated NSCLC patients who acquired MET-V1092I or MET-H1094Y may benefit from combinatorial therapy with EGFR-TKI and MET-TKI, providing insights into personalized medical treatment.

Prognostic analysis and risk stratification of lung adenocarcinoma undergoing EGFR-TKI therapy with time-serial CT-based radiomics signature

OBJECTIVES

To evaluate the value of time-serial CT radiomics features in predicting progression-free survival (PFS) for lung adenocarcinoma (LUAD) patients after epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) therapy.

MATERIALS AND METHODS

LUAD patients treated with EGFR-TKIs were retrospectively included from three independent institutes and divided into training and validation cohorts. Intratumoral and peritumoral features were extracted from time-serial non-contrast chest CT (including pre-therapy and first follow-up images); moreover, the percentage variation per unit time (day) was introduced to adjust for the different follow-up periods of each patient. Test-retest was performed to exclude irreproducible features, while the Boruta algorithm was used to select critical radiomics features. Radiomics signatures were constructed with random forest survival models in the training cohort and compared against baseline clinical characteristics through Cox regression and nonparametric testing of concordance indices (C-indices).

RESULTS

The training cohort included 131 patients (74 women, 56.5%) from one institute and the validation cohort encompassed 41 patients (24 women, 58.5%) from two other institutes. The optimal signature contained 10 features and 7 were unit time feature variations. The comprehensive radiomics model outperformed the pre-therapy clinical characteristics in predicting PFS (training: 0.78, 95% CI: [0.72, 0.84] versus 0.55, 95% CI: [0.49, 0.62], p < 0.001; validation: 0.72, 95% CI: [0.60, 0.84] versus 0.54, 95% CI: [0.42, 0.66], p < 0.001).

CONCLUSION

Radiomics signature derived from time-serial CT images demonstrated optimal prognostic performance of disease progression. This dynamic imaging biomarker holds the promise of monitoring treatment response and achieving personalized management.

KEY POINTS

• The intrinsic tumor heterogeneity can be highly dynamic under the therapeutic effect of EGFR-TKI treatment, and the inevitable development of drug resistance may disrupt the duration of clinical benefit. Decision-making remained challenging in practice to detect the emergence of acquired resistance during the early response phase. • Time-serial CT-based radiomics signature integrating intra- and peritumoral features offered the potential to predict progression-free survival for LUAD patients treated with EGFR-TKIs. • The dynamic imaging signature allowed for prognostic risk stratification.

EGFR-Tyrosine Kinase Inhibitors Induced Activation of the Autocrine CXCL10/CXCR3 Pathway through Crosstalk between the Tumor and the Microenvironment in EGFR-Mutant Lung Cancer

CXCL10 is a cytokine that is elevated during EGFR-TKI treatment in the tumor microenvironment of lung cancer. Here, we report an original study that the impact of the CXCL10/CXCR3 pathway on EGFR-TKI resistance in EGFR-mutant lung cancer through a cytokine array analysis during in vitro coculture with tumor cells and activated PBMCs treated with EGFR-TKI, as well as the serial analysis of CXCL10 in EGFR-mutant lung cancer transgenic mice during EGFR-TKI treatment. In EGFR-mutant tumor cells cocultured with activated PBMCs, EGFR-TKI treatment increased CXCL10 in the supernatant; this activated CXCR3 in the tumor cells to induce the phosphorylation of Src and the NF-κB subunit, p65, and the expression of HIF-1α. CXCL10 siRNA treatment of EGFR-mutant tumor cells also decreased CXCL10 in the supernatant from coculturing with activated PBMCs, suggesting that the effects of CXCL10 occur via autocrine and paracrine pathways. Importantly, elevated CXCL10/CXCR3 signaling was recapitulated in a transgenic lung cancer mouse model. Our results show that increased CXCL10 levels during early EGFR-TKI treatment stimulate oncogenic signaling of persistent tumor cells to contribute to EGFR-TKI resistance via autocrine and paracrine pathways.

Synergistic Effect of HAD-B1 and Afatinib Against Gefitinib Resistance of Non-Small Cell Lung Cancer

In epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC), acquired resistance to EGFR tyrosine kinase inhibitors (TKI) leads to disease progression. Strategies to overcome the resistance are required in treatment for advanced lung cancer. In this study, we investigated the therapeutic effect of afatinib and HangAmDan-B1 (HAD-B1) co-administration in gefitinib-resistant NSCLC using HCC827-GR, NSCLC cell line with gefitinib resistance, and the HCC827-GR cell implanted mouse model. HAD-B1 consists of 4 herbs, Panax notoginseng Radix, Cordyceps militaris, Panax ginseng C. A. Mey, and Boswellia carteri Birdwood, and has been reported to be effective in patients with advanced lung cancer in clinical practice. Our findings demonstrated that HAD-B1 combined with afatinib markedly inhibited cell proliferation and induced apoptosis compared to afatinib monotherapy and HAD-B1 monotherapy. Inhibition of HCC827-GR cell proliferation by HAD-B1 occurred through MET amplification and reduced phosphorylation, and the synergistic effect of afatinib and HAD-B1 induced cell cycle arrest and apoptosis in HCC827-GR cells via the downregulation of ERK and mTOR signaling pathways. In hematology and biochemistry tests, HAD-B1 alleviated the toxicity of tumor. In conclusion, HAD-B1 combined with afatinib would be a promising therapeutic strategy for NSCLC with EGFR-TKI resistance.

TP53 Co-Mutation Status Association with Clinical Outcomes in Patients with EGFR-Mutant Non-Small Cell Lung Cancer

TP53 co-mutations have shown association with poor prognosis in various solid tumors. For EGFR-mutated advanced non-small cell lung cancer (aNSCLC), conflicting results exist regarding its impact on survival. Clinical outcomes and genomic data were obtained retrospectively from the real-world (rw) de-identified clinicogenomic database. Patients who initiated therapy for EGFR-mutated aNSCLC between January 2014 and December 2020 were identified. Clinical outcomes were evaluated by TP53-mutational status. In 356 eligible EGFR-mutated aNSCLC patients (median age 68 years), 210 (59.0%) had TP53 co-mutation and 146 (41.0%) had TP53 wild-type tumor. Unadjusted analysis showed significantly shorter survival in patients with TP53 co-mutation versus TP53 wild-type (rw progression-free survival [rwPFS]: HR = 1.4, 95% CI 1.1-1.9, p = 0.0196; overall survival [OS]: HR = 1.6, 95% CI 1.1-2.2, p = 0.0088). Multivariable analysis confirmed independent association between TP53 co-mutation and worse rwPFS (HR = 1.4, 95% CI 1.0-0.9, p = 0.0280) and OS (HR = 1.4, 95% CI 1.0-2.0, p = 0.0345). Directionally consistent findings were observed for response rates, and subgroups by EGFR-activating mutation and first-line (1 L) therapy, with more pronounced negative effect in 1 L EGFR-TKI subgroup. TP53 co-mutations negatively affected survival in patients with EGFR-mutated aNSCLC receiving standard 1 L therapy in real-world practice.

Radiomics for prediction of response to EGFR-TKI based on metastasis/brain parenchyma (M/BP)-interface

PURPOSE

To evaluate the potential of subregional radiomics as a novel tumor marker in predicting epidermal growth factor receptor (EGFR) mutation status and response to EGFR-tyrosine kinase inhibitor (TKI) therapy in NSCLC patients with brain metastasis (BM).

MATERIALS AND METHODS

We included 230 patients from center 1, and 80 patients were included from center 2 to form a primary and external validation cohort, respectively. Patients underwent contrast-enhanced T1-weighted and T2-weighted MRI scans before treatment. The individual- and population-level clustering was used to partition the peritumoral edema area (POA) into phenotypically consistent subregions. Radiomics features were calculated and selected from the tumor active area (TAA), POA and subregions, and used to develop models. Prediction values of each region were investigated and compared with receiver operating characteristic curves and Delong test.

RESULTS

For predicting EGFR mutations, a multi-region combined model (EGFR-Fusion) was developed based on joint of the partitioned metastasis/brain parenchyma (M/BP)-interface and TAA, and generated the highest prediction performance in the training (AUC = 0.945, SEN = 0.878, SPE = 0.937), internal validation (AUC = 0.880, SEN = 0.733, SPE = 0.969), and external validation (AUC = 0.895, SEN = 0.875, SPE = 0.800) cohorts. For predicting response to EGFR-TKI, the developed multi-region combined model (TKI-Fusion) yielded predictive AUCs of 0.869 (SEN = 0.717, SPE = 0.884), 0.786 (SEN = 0.708, SPE = 0.818), and 0.802 (SEN = 0.750, SPE = 0.800) in the training, internal validation and external validation cohort, respectively.

CONCLUSION

Our study revealed that complementary information regarding the EGFR status and response to EGFR-TKI can be provided by subregional radiomics. The proposed radiomics models may be new markers to guide treatment plans for NSCLC patients with BM.

Pathological Roles of Pulmonary Cells in Acute Lung Injury: Lessons from Clinical Practice

Interstitial lung diseases (ILD) are relatively rare and sometimes become life threatening. In particular, rapidly progressive ILD, which frequently presents as acute lung injury (ALI) on lung histopathology, shows poor prognosis if proper and immediate treatments are not initiated. These devastating conditions include acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF), clinically amyopathic dermatomyositis (CADM), epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-induced lung injury, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection named coronavirus disease 2019 (COVID-19). In this review, clinical information, physical findings, laboratory examinations, and findings on lung high-resolution computed tomography and lung histopathology are presented, focusing on majorly damaged cells in each disease. Furthermore, treatments that should be immediately initiated in clinical practice for each disease are illustrated to save patients with these diseases.

Construction of the model for predicting prognosis by key genes regulating EGFR-TKI resistance

Background: Previous studies have suggested that patients with lung adenocarcinoma (LUAD) will significantly benefit from epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI). However, many LUAD patients will develop resistance to EGFR-TKI. Thus, our study aims to develop models to predict EGFR-TKI resistance and the LUAD prognosis. Methods: Two Gene Expression Omnibus (GEO) datasets (GSE31625 and GSE34228) were used as the discovery datasets to find the common differentially expressed genes (DEGs) in EGFR-TKI resistant LUAD profiles. The association of these common DEGs with LUAD prognosis was investigated in The Cancer Genome Atlas (TCGA) database. Moreover, we constructed the risk score for prognosis prediction of LUAD by LASSO analysis. The performance of the risk score for predicting LUAD prognosis was calculated using an independent dataset (GSE37745). A random forest model by risk score genes was trained in the training dataset, and the diagnostic ability for distinguishing sensitive and EGFR-TKI resistant samples was validated in the internal testing dataset and external testing datasets (GSE122005, GSE80344, and GSE123066). Results: From the discovery datasets, 267 common upregulated genes and 374 common downregulated genes were identified. Among these common DEGs, there were 59 genes negatively associated with prognosis, while 21 genes exhibited positive correlations with prognosis. Eight genes (ABCC2, ARL2BP, DKK1, FUT1, LRFN4, PYGL, SMNDC1, and SNAI2) were selected to construct the risk score signature. In both the discovery and independent validation datasets, LUAD patients with the higher risk score had a poorer prognosis. The nomogram based on risk score showed good performance in prognosis prediction with a C-index of 0.77. The expression levels of ABCC2, ARL2BP, DKK1, LRFN4, PYGL, SMNDC1, and SNAI2 were positively related to the resistance of EGFR-TKI. However, the expression level of FUT1 was favorably correlated with EGFR-TKI responsiveness. The RF model worked wonderfully for distinguishing sensitive and resistant EGFR-TKI samples in the internal and external testing datasets, with predictive area under the curves (AUC) of 0.973 and 0.817, respectively. Conclusion: Our investigation revealed eight genes associated with EGFR-TKI resistance and provided models for EGFR-TKI resistance and prognosis prediction in LUAD patients.

Mechanisms of EGFR-TKI-Induced Apoptosis and Strategies Targeting Apoptosis in EGFR-Mutated Non-Small Cell Lung Cancer

Homeostasis is achieved by balancing cell survival and death. In cancer cells, especially those carrying driver mutations, the processes and signals that promote apoptosis are inhibited, facilitating the survival and proliferation of these dysregulated cells. Apoptosis induction is an important mechanism underlying the therapeutic efficacy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) for EGFR-mutated non-small cell lung cancer (NSCLC). However, the mechanisms by which EGFR-TKIs induce apoptosis have not been fully elucidated. A deeper understanding of the apoptotic pathways induced by EGFR-TKIs is essential for the developing novel strategies to overcome resistance to EGFR-TKIs or to enhance the initial efficacy through therapeutic synergistic combinations. Recently, therapeutic strategies targeting apoptosis have been developed for cancer. Here, we review the state of knowledge on EGFR-TKI-induced apoptotic pathways and discuss the therapeutic strategies for enhancing EGFR-TKI efficiency. We highlight the great progress achieved with third-generation EGFR-TKIs. In particular, combination therapies of EGFR-TKIs with anti-vascular endothelial growth factor/receptor inhibitors or chemotherapy have emerged as promising therapeutic strategies for patients with EGFR-mutated NSCLC. Nevertheless, further breakthroughs are needed to yield an appropriate standard care for patients with EGFR-mutated NSCLC, which requires gaining a deeper understanding of cancer cell dynamics in response to EGFR-TKIs.

[STE029 Overcomes EGFR-TKI Resistance in Human Lung Adenocarcinoma]

BACKGROUND

Acquired and primary resistance to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is still the bottleneck of clinical treatment of advanced non-small cell lung cancer (NSCLC). STE029 is a novel anticancer drug which consists of 3-hydroxy-3-methylglutarylcoenzyme A reductase (HMGCR) inhibitor and novel cancer cell membrane targeting molecular. This study aimed to investigate the reversal mechanism of EGFR-TKI resistance by STE029 in lung adenocarcinoma.

METHODS

CCK8 test was used to test the cell viability and survival rate of EGFR mutated PC9 cell (Gefitinib sensitive), PC9/BB4 cell (acquired Gefitinib resistant), and EGFR wild type A549 cell after treatment of STE029, Gefitinib or combination of both. EdU test was applied to detect changes in cell cycle and Hoechst 33258 was applied to detect apoptosis rate in overcoming the EGFR-TKI resistance. The activity of EGFR/PI3K/Akt, cell cycle and apoptosis signal pathways were examined. In vivo, nude mice were exposed to STE029, Gefitinib and STE029+Gefitinib for 5 wk. And the the tumor volume was measured and tumor weight was obtained on the last day.

RESULTS

(1) PC9 cells was highly sensitive to Gefitinib, while PC9/BB4 and A549 cell showed significant resistance to Gefitinib treatment; (2) STE029+Gefitinib treatment could significantly decrease the 50% inhibitory concentrarion (IC₅₀) of Gefitinib in PC9, PC9/BB4 and A549 cells (P<0.05, respectively); (3) In PC9 and PC9/BB4 cells, STE029+Gefitinib can block cell cycle and inhibit cell proliferation (P<0.001), while there was no significant difference in apoptosis rate among three drug intervention groups (P>0.05); However, apoptosis rate was increased in STE029+Gefitinib group in A549 cell (P<0.01), while no significance detected in cell proliferation (P>0.05). (4) In PC9 and PC9/BB4 cells, the combination of STE029 and Gefitinib could downregulate p-EGFR, p-Akt, p-Cyclin D1 and Cyclin D1 (P<0.001), and upregulate the expression of GSK-3β (P<0.001), and the expression of cleaved caspase-8, caspase-8 cleaved caspase-9, caspase-9 showed no difference among groups (P>0.05). In A549 cells, the combination of STE029 and Gefitinib could downregulate p-Akt (P<0.001) and upregulate cleaved caspase-8 and cleaved caspase-9 (P<0.001); (5)In vivo, the combination of STE029 and Gefitinib effectively inhibited tumor development and progression compared to STE029 alone or Gefitinib alone, with significant difference (P<0.05) in PC9 and PC9/BB4 xenografted tumor.

CONCLUSIONS

STE029 could sensitize Gefitinib by inhibiting EGFR/PI3K/Akt pathway, blocking the tumor cell cycle and proliferation and inducing apoptosis through caspase-8 and caspase-9 dependent pathway. STE029 deserves further investigations in overcoming EGFR-TKI resistance in lung cancer.

Histomorphological transformation from non-small cell lung carcinoma to small cell lung carcinoma after targeted therapy or immunotherapy: A report of two cases

Molecular targeting and immunotherapy provide durable responses for advanced lung cancer clinical therapy in many patients. However, the mechanisms of occurrence of progressive disease and resistance to targeted therapy and immunotherapy have not been elucidated. Herein, we report two cases of small cell transformation of non-small cell lung cancer (NSCLC) after targeted therapy or immunotherapy. The first case was a 63-year-old female patient presenting with cough and expectoration. Left lung invasive adenocarcinoma was diagnosed after left lung tumor biopsy. After epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) targeted therapy for almost 2 years, disease progression and symptom aggravation were observed. Pathological and immunohistochemical staining results after biopsy revealed small cell lung cancer (SCLC). The second case was a 75-year-old male patient diagnosed with stage IV squamous cell carcinoma of the lung, who received carboplatin/paclitaxel adjuvant chemotherapy and pembrolizumab treatment with partial response. Disease progression and metastasis occurred within 15 cycles of immunotherapy. Computed tomography revealed a lower left lung tumor. Cytological examination of lung lavage fluid and biopsy under thoracoscope revealed SCLC. In conclusion, histological transformation to SCLC is a potential mechanism of NSCLC resistance to targeted therapy or immunotherapy. During treatment, clinicians should monitor serum tumor markers or genome sequencing, particularly in patients with disease progression, as this may be beneficial for early detection of SCLC transformation. Repeated biopsy can be performed if necessary, and the therapeutic regimen can be adjusted in a timely manner according to the results of molecular pathological tests for personalization and whole-process management.

A Phase II Trial on Osimertinib as a First-Line Treatment for EGFR Mutation-Positive Advanced NSCLC in Elderly Patients: The SPIRAL-0 Study

BACKGROUND

Osimertinib is one of the standard first-line treatments for advanced non-small cell lung cancer in patients with epidermal growth factor receptor (EGFR) mutations, because it achieves significantly longer progression-free survival (PFS) than conventional first-line treatments (hazard ratio: 0.46). However, the efficacy and safety of osimertinib as a first-line treatment for patients aged ≥75 years remain unclear.

METHODS

This phase II study was performed to prospectively investigate the efficacy and safety of osimertinib for elderly patients with EGFR mutation-positive advanced non-small cell lung cancer. The primary endpoint was 1-year PFS rate; secondary endpoints were overall response rate (ORR), PFS, overall survival (OS), and safety.

RESULTS

Thirty-eight patients were included in the analysis. The 1-year PFS rate was 59.4% (95% confidence interval [CI], 46.1%-72.7%), which did not meet the primary endpoint (the threshold 1-year PFS rate of 50% predicted using data from the NEJ003 study). The most common grade 3/4 adverse events were rash/dermatitis acneiform/ALT increased/hypokalemia (2 patients, 5%). Seven patients developed pneumonitis (17.5%). There were no other cases of treatment discontinuation due to adverse events other than pneumonitis.

CONCLUSION

Although this study did not meet the primary endpoint, osimertinib was tolerable for elderly patients with EGFR mutation-positive advanced non-small cell lung cancer. (Japan Registry of Clinical Trials [JRCT] ID number: jRCTs071180007).

Bioanalytical assay for the quantification of the tyrosine kinase inhibitor EAI045 and its major metabolite PIA in mouse plasma and tissue homogenates using liquid chromatography-tandem mass spectrometry

EAI045 is a tyrosine kinase inhibitor (TKI) that targets the mutant epidermal growth factor receptor (EGFR). It was developed to control resistance to available EGFR TKIs. In this study, a major metabolite of EAI045, (5-fluoro-2-hydroxyphenyl)(1-oxo-1,3-dihydro-2H-isoindol-2-yl)acetic acid (PIA), was discovered as a hydrolysis product of the parent drug. A validated assay for both analytes in mouse plasma and tissue homogenates from brain, kidney, liver, lung, spleen, and small intestine with content was set up using LC-MS/MS. Samples were prepared by protein precipitation with acetonitrile and with PLX4720 as internal standard. Separation was performed on a bridged ethylene hybrid C₁₈ column by gradient elution with 0.1% v/v formic acid and methanol. Using positive electrospray, detection was performed in selected reaction monitoring mode. A linear calibration range of 2-2,000 ng/ml was used and validated for both analytes. Precision values ranged between 2.0 and 7.5% for EAI045 and between 2.2 and 12.1% for the metabolite, and accuracy values were between 91.1 and 107.6% for EAI045 and between 87.6 and 100.6% for the metabolite. Both analytes were sufficiently stable under the relevant analytical conditions. Finally, the assay was applied to analyze mouse plasma and tissue levels in a pharmacokinetic study in FVB/NRj wild-type female mice treated with oral EAI045.

Overview of the multifaceted resistances toward EGFR-TKIs and new chemotherapeutic strategies in non-small cell lung cancer

The role of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) has been vastly studied over the last decade. This has led to the rapid development of many generations of EGFR tyrosine kinase inhibitors (EGFR-TKIs). However, patients treated with third-generation TKIs (osimertinib, avitinib and rociletinib) targeting the EGFR T790M mutation have shown emerging resistances and relapses. Therefore, further molecular understanding of NSCLC mutations, bypass signalling, tumour microenvironment and the existence of cancer stem cells to overcome such resistances is warranted. This will pave the way for designing novel and effective chemotherapies to improve patients' overall survival. In this review, we provide an overview of the multifaceted mechanism of resistances towards EGFR-TKIs, as well as the challenges and perspectives that should be addressed in strategising chemotherapeutic treatments to overcome the ever evolving and adaptive nature of NSCLC.

EGFR-TKI re-administration after osimertinib failure in T790M mutation loss cases with re-biopsy

Data on the re-administration of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) after osimertinib failure in patients with T790M-positive non-small cell lung cancer (NSCLC) is limited. EGFR-TKI re-administration efficacy may vary between patients with T790M loss and those with T790M persistent with re-biopsy after osimertinib treatment. Patients who received EGFR-TKI re-administration (gefitinib, erlotinib, afatinib, dacomitinib, and osimertinib) after osimertinib failure were identified from our database. T790M mutation status before EGFR-TKI re-administration was analyzed via repeat biopsy. We retrospectively evaluated the efficacy of EGFR-TKI re-administration, especially differences according to the T790M mutation status, via repeat biopsy. Until June 2020, 28 patients received EGFR-TKI re-administration and 17 underwent repeat biopsy after osimertinib failure. Patients were divided into three groups, including the T790M loss group, where active mutation persisted and T790M was lost (13/17); T790M remaining group, where both the active mutation and T790M persisted (3/17); and active mutation loss group where both the active mutation and T790M were lost (1/17). The overall response rate (ORR) of EGFR-TKI re-administration in the T790M loss group was 31% and the disease control rate (DCR) was 54%, which were higher than the ORR of 21% and DCR of 43% in the entire patient population. ORR and DCR of the not re-biopsy group were low (9% and 27%, respectively). The therapeutic effect of EGFR-TKI re-administration in patients with T790M-positive NSCLC after osimertinib failure is limited. EGFR-TKI re-administration may be considered in cases of T790M loss after repeat biopsy.

RET fusions as primary oncogenic drivers and secondary acquired resistance to EGFR tyrosine kinase inhibitors in patients with non-small-cell lung cancer

BACKGROUND

RET fusions are rare oncogenic drivers in non-small cell lung cancer (NSCLC). While activating RET rearrangements are found in NSCLC patients harboring epidermal growth factor receptor (EGFR) genetic alterations at resistance to EGFR inhibitors, the extent to which co-occurring genomic alterations exist and how they might affect prognosis or therapy response is poorly understood.

METHODS

Targeted next-generation sequencing (NGS) was used to assess 380 baseline patients with primary RET fusions and 71 EGFR-mutated NSCLC patients who acquired RET fusions after developing resistance to EGFR-tyrosine kinase inhibitors (EGFR-TKIs).

RESULTS

Primary RET fusions were more likely associated with females and younger age, with KIF5B being the predominant fusion partner. In baseline patients, both SMAD4 (5.3% vs. 0.0%, P = 0.044) and MYC copy-number gain variants (6.9% vs. 0.0%, P = 0.009) were more frequently co-mutated with KIF5B-RET than CCDC6-RET. By contrast, CDKN2A (11.3% vs. 2.4%, P = 0.003) mutations were significantly enriched in CCDC6-RET-rearranged baseline patients. A significant increase in the proportion of CCDC6-RET was observed in acquired RET-rearranged patients (47.3% vs. 22.5%, P < 0.001). The median progression-free survival (PFS) of patients harboring RB1 and TP53 double-mutations (5.5 vs. 10.0 months, P = 0.020) or ERBB2 amplification (5.6 vs. 10.0 months, P = 0.041) was significantly shorter than the wild-type counterparts. Moreover, we identified that RET fusions were more likely associated with acquired resistance (AR) to third-generation EGFR-TKIs than previous generations of EGFR-TKIs.

CONCLUSIONS

In conclusion, we depicted the mutational profiles of NSCLC patients who harbor RET fusions at baseline or after resistance to EGFR-TKIs. Furthermore, our results suggest that RET fusions mediate secondary resistance to third-generation EGFR-TKIs and might be associated with poor prognosis in patients with NSCLC.

Efficacy and safety of EGFR inhibitors and radiotherapy in locally advanced non-small-cell lung cancer: a meta-analysis

Aim: To assess the efficacy and safety of EGFR inhibitors combined with (chemo)radiotherapy in unresectable, locally advanced non-small-cell lung cancer. Materials & methods: A systematic review and meta-analysis of prospective trials was performed. Results: Twenty-eight studies of 1640 patients were included. In patients harboring EGFR-sensitive mutations, the pooled objective response rate, 1-year overall survival rate and 1-year progression-free survival rate of EGFR-TKIs + (chemo)radiotherapy were 0.803, 0.766 and 0.554, respectively. Compared with chemoradiotherapy, the addition of EGFR inhibitors did not significantly increase the risk of grade ≥3 pneumonitis and esophagitis. Conclusion: EGFR-tyrosine kinase inhibitors combined with (chemo)radiotherapy are tolerable and the clinical benefit is promising, especially in patients with EGFR-sensitive mutations.

The histone deacetylase SIRT6 promotes glycolysis through the HIF-1α/HK2 signaling axis and induces erlotinib resistance in non-small cell lung cancer

Erlotinib is a first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Overcoming erlotinib resistance is crucial to improve the survival of advanced non-small cell lung cancer (NSCLC) patients with sensitive EGFR mutations. It is also an important clinical problem that urgently needs a solution. In this study, we explored strategies to overcome erlotinib resistance from the perspective of energy metabolism. SIRT6 is a histone deacetylase. Here, we found that high expression of SIRT6 is associated with poor prognosis of lung adenocarcinoma, especially in EGFR-mutated NSCLC patients. The next cell experiment found that SIRT6 expression increased in erlotinib-resistant cells, and SIRT6 expression was negatively correlated with the sensitivity of NSCLC to erlotinib. Inhibition of SIRT6 promoted erlotinib-induced apoptosis in erlotinib-resistant cells, and glycolysis in drug-resistant cells was also inhibited. Functional studies have shown that SIRT6 increases glycolysis through the HIF-1α/HK2 signaling axis in drug-resistant cells and inhibits the sensitivity of NSCLC cells to erlotinib. In addition, the HIF-1α blocker PX478-2HCL attenuated the glycolysis and erlotinib resistance induced by SIRT6. More importantly, we confirmed the antitumor effect of SIRT6 inhibition combined with erlotinib in NSCLC-bearing mice. Our findings indicate that the cancer metabolic pathway regulated by SIRT6 may be a new target for attenuating NSCLC erlotinib resistance and has potential as a biomarker or therapeutic target to improve outcomes in NSCLC patients.

Primary lesion radiotherapy during first-line icotinib treatment in EGFR-mutated NSCLC patients with multiple metastases and no brain metastases: a single-center retrospective study

BACKGROUND

The most frequent mode of progression in the majority of non-small cell lung cancer (NSCLC) patients treated with  Epidermal growth factor - receptor tyrosine kinase inhibitors (EGFR-TKIs) is failure to respond to treatment at the primary lesion, suggesting that concurrent radiotherapy (CRT) to the primary lesion (CPRT) during first-line treatment with EGFR-TKI may be a novel therapeutic approach with a potential of additional benefit for metastatic NSCLC. Therefore, this study investigated the progression-free survival (PFS) and safety of CPRT during first-line icotinib treatment in NSCLC patients with EGFR mutations.

METHODS

EGFR-mutant NSCLC patients diagnosed with limited multiple metastases were treated with first-line icotinib. The decision to treat the primary lesions with radiation largely depended on the patient's preference. The study endpoints included PFS, toxicity, progression pattern, and acquisition of the T790M mutation.

RESULTS

The median PFS in the CPRT and Non-CPRT groups was 13.6 and 10.6 months (hazard ratio [HR] 0.23, 95% confidence interval [CI] 0.15-0.37, P < 0.001). Subgroup analysis showed that the results were statistically significant with 14.7 and 11.5 months for the 19del mutation (HR 0.20, 95% CI 0.10-0.40, P < 0.001) and 12.9 and 9.9 months for the L858R mutation (HR 0.25, 95% CI 0.13-0.48, P < 0.001). There were no reports of interstitial pneumonia associated with treatment at grade 4 or above. Patients who received CPRT during first-line icotinib treatment had the potential to decrease the primary lesion progression (P < 0.05) without increasing newly metastatic lesions (P > 0.05). The proportion of acquired T790M mutations was 26.7% and 45.7% in both groups (P > 0.05).

CONCLUSION

This study suggests that CPRT is a viable option for patients with EGFR-sensitive mutations in NSCLC with limited multiple metastases during first-line icotinib treatment, which can significantly improve PFS with acceptable toxicities. Data on progression patterns and T790M mutations suggest the need to further investigate the benefits of radiation treatment from a molecular perspective.