Clinical characteristics of non-small cell lung cancer patients who experienced acquired resistance during gefitinib treatment

Dynamics of disease progression during treatment with Osimertinib in patients with EGFR T790M-positive non-small cell lung cancer

BACKGROUND

Patterns of treatment failure and subsequent treatment in non-small cell lung cancer (NSCLC) patients treated with osimertinib are scarcely known. We analyzed the disease progression during osimertinib treatment to identify potential treatment strategies.

METHODS

We identified advanced NSCLC patients who commenced osimertinib treatment after progression on previous epidermal growth factor receptor (EGFR)-tyrosine-kinase inhibitor (TKI) from June 2014 to November 2018 from electronic records. Patients' tumor characteristics, efficacy outcomes, affected organs from radiology studies, and treatment modalities before and after osimertinib were analyzed.

RESULTS

Eighty-four patients were included. At osimertinib initiation, bone (50.0%) and brain (41.9%) were the commonest single metastatic sites, whereas thoracic involvement (73.3%) was more frequent than bone (27.4%) or brain (20.2%) metastasis during disease progression on osimertinib. Oligo-progressive disease (PD) and central nervous system (CNS)-sanctuary PD were observed in 15 (17.9%) and 3 (3.6%) patients, respectively. Most patients without brain metastasis (BM) at osimertinib initiation remained BM-free (46/49, 93.9%), and 60% of patients (21/35) with pre-existing BM showed intracranial disease control despite extracranial PD. The resistance mechanisms to osimertinib were explored in 23 patients (27.4%), and T790M-loss was observed in 14 patients (60.9%) who had worse survival outcomes than those without T790M-loss (progression-free survival, 5.4 vs. 16.5 months, p = 0.02; overall survival, not reached, p = 0.03).

CONCLUSION

PD during osimertinib treatment occurred preferentially in the thorax and pre-existing sites. Extracranial PD prevailed over intracranial PD regardless of baseline BM and prior brain radiation. These results support osimertinib's intracranial efficacy and may guide treatment strategies for EGFR-mutated NSCLC with BM.

Sequential occurrence of T790M mutation and small cell lung cancer transformation in EGFR-positive lung adenocarcinoma: A case report

BACKGROUND

The emergence of secondary drug resistance when treating epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer (NSCLC) using EGFR-tyrosine kinase inhibitors (EGFR-TKIs), seriously affects the therapeutic efficacy and survival of patients. Here, we report a case of advanced NSCLC focusing on the application of multiple biopsy modalities to reveal the development of multiple resistance mechanisms during targeted therapies.

CASE SUMMARY

A 54-year-old male patient presented with EGFR 19Del-mutated advanced lung adenocarcinoma, and exhibited the development of a T790M mutation during initial TKI treatment. Following 3 mo of Osimertinib treatment, a mixed response was observed. Tissue biopsy of the progressive lesion showed transformation to small cell lung cancer (SCLC) harboring RB1 and TP53 mutations, with loss of the original T790M mutation. A standard chemotherapy regimen with Anlotinib for SCLC was administered. Repeat biopsy revealed adenocarcinoma combined with SCLC after tumor progression. The patient’s overall survival was 24 mo.

CONCLUSION

Multiple biopsy modalities can reveal the development of multiple resistance mechanisms which help with treatment decision-making. Comprehensive treatment regimens according to the drug resistance mechanism significantly improved the prognosis of such patients.

Sequential occurrence of T790M mutation and small cell lung cancer transformation in EGFR-positive lung adenocarcinoma: A case report

BACKGROUND

The emergence of secondary drug resistance when treating epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer (NSCLC) using EGFR-tyrosine kinase inhibitors (EGFR-TKIs), seriously affects the therapeutic efficacy and survival of patients. Here, we report a case of advanced NSCLC focusing on the application of multiple biopsy modalities to reveal the development of multiple resistance mechanisms during targeted therapies.

CASE SUMMARY

A 54-year-old male patient presented with EGFR 19Del-mutated advanced lung adenocarcinoma, and exhibited the development of a T790M mutation during initial TKI treatment. Following 3 mo of Osimertinib treatment, a mixed response was observed. Tissue biopsy of the progressive lesion showed transformation to small cell lung cancer (SCLC) harboring RB1 and TP53 mutations, with loss of the original T790M mutation. A standard chemotherapy regimen with Anlotinib for SCLC was administered. Repeat biopsy revealed adenocarcinoma combined with SCLC after tumor progression. The patient’s overall survival was 24 mo.

CONCLUSION

Multiple biopsy modalities can reveal the development of multiple resistance mechanisms which help with treatment decision-making. Comprehensive treatment regimens according to the drug resistance mechanism significantly improved the prognosis of such patients.

Novel Insights Into MALAT1 Function as a MicroRNA Sponge in NSCLC

The long non-coding RNA metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) was initially found to be overexpressed in early non-small cell lung cancer (NSCLC). Accumulating studies have shown that MALAT1 is overexpressed in the tissue or serum of NSCLC and plays a key role in its occurrence and development. In addition, the expression level of MALAT1 is significantly related to the tumor size, stage, metastasis, and distant invasion of NSCLC. Therefore, MALAT1 could be used as a biomarker for the early diagnosis, severity assessment, or prognosis evaluation of NSCLC patients. This review describes the basic properties and biological functions of MALAT1, focuses on the specific molecular mechanism of MALAT1 as a microRNA sponge in the occurrence and development of NSCLC in recent years, and emphasizes the application and potential prospect of MALAT1 in molecular biological markers and targeted therapy of NSCLC.

Polyphyllin I reverses the resistance of osimertinib in non-small cell lung cancer cell through regulation of PI3K/Akt signaling

Lung cancer is considered the main cause of cancer mortality worldwide. Osimertinib, a third-generation EGFR-TKI, has been approved and administrated for treating patients with either EGFR T790M mutation or EGFR sensitive mutation. However, resistance to osimertinib emerges and has been considered to be the main obstacle in lung cancer treatment. Polyphyllin I is isolated from the natural herb Paris polyphylla and exhibits anti-cancer activities. In the present study, we identify Polyphyllin I to reverse the resistance of osimertinib in vitro and in vivo. The results showed that Polyphyllin I reversed the resistance of osimertinib through promoting apoptosis, modulating the PI3K/Akt signaling, and regulating the expression of apoptosis-related proteins in osimertinib-resistant cell lines. In vivo study confirmed the results, showing that the tumor growth was significantly suppressed in the Polyphyllin I/osimertinib group compared to the osimertinib group. It has been clarified that Polyphyllin I could reverse the resistance of osimertinib in osimertinib-resistant non-small cell of lung cancer in vitro and in vivo. The underlying mechanism might be related to the downregulation of the PI3K/Akt signaling and increase of the expression of apoptosis-related proteins, suggesting that Polyphyllin I was a promising therapeutic agent for reversing the resistance of osimertinib.

Strategies to overcome acquired resistance to EGFR TKI in the treatment of non-small cell lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) represents a paradigm shift in the treatment of non-small cell lung cancer (NSCLC) patients and has been the first-line therapy in clinical practice. While erlotinib, gefitinib and afatinib have achieved superior efficacy in terms of progression-free survival and overall survival compared with conventional chemotherapy in NSCLC patients, most people inevitably develop acquired resistance to them, which presents another challenge in the treatment of NSCLC. The mechanisms of acquired resistance can be classified as three types: target gene mutation, bypass signaling pathway activation and histological transformation. And the most common mechanism is T790M which accounts for approximately 50% of all subtypes. Many strategies have been explored to overcome the acquired resistance to EGFR TKI. Continuation of EGFR TKI beyond progressive disease is confined to patients in asymptomatic stage when the EGFR addiction is still preserved in some subclones. While the combination of EGFR TKI and chemotherapy or other targeted agents has improved the survival benefit in EGFR TKI resistant patients, there are controversies within them. The next-generation EGFR TKI and immunotherapy represent two novel directions for overcoming acquired resistance and have achieved promising efficacy. Liquid biopsy provides surveillance of the EGFR mutation by disclosing the entire genetic landscape but tissue biopsy is still indispensable because of the considerable rate of false-negative plasma.

Relationship between EGFR mutation and computed tomography characteristics of the lung in patients with lung adenocarcinoma

Background

The aim of this study was to investigate the relationship between EGFR mutation and computed tomography (CT) features in patients with adenocarcinoma of the lung.

Methods

One hundred and ninety two lung adenocarcinoma patients who underwent surgery were retrospectively included in this study. Examination of EGFR gene mutation was performed on all resected tumor samples. The 192 recruited lung adenocarcinoma patients were divided into groups according to EGFR mutation status: patients with mutations in exons 18–21 (effective mutated, n = 61) and non‐mutated (n = 131). The clinical characteristics and lung CT imaging features of the two groups were recorded and compared. Univariate and logistic regression analysis were performed to identify the independent risk factors relevant to effective EGFR gene mutation.

Results

The independent risk factors relevant to effective EGFR mutation were evaluated by logistic regression test. The results indicated that female gender (odds ratio [OR] 3.23), lung CT features of lymphangitis carcinomatosa (OR 2.66), semi‐solid lesion density (OR 3.56), and spicule sign (OR 1.61) were independent risk factors relevant to EGFR mutation.

Conclusion

Female patients with lung CT features of lymphangitis carcinomatosa, semi‐solid lesion density, and spicule sign are more prone to harbor EGFR gene mutations and are more likely to benefit from targeted therapy.

Three new disease-progression modes in NSCLC patients after EGFR-TKI treatment by next-generation sequencing analysis

INTRODUCTION

Most non-small-cell lung cancer (NSCLC) patients who exhibit good clinical responses to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) will inevitably develop disease progression. Herein, through next-generation sequencing (NGS), we aimed to investigate three new disease-progression modes of NSCLC patients after EGFR-TKI treatment.

MATERIALS AND METHODS

Patients with sensitive EGFR-mutations who acquired resistance to EGFR-TKIs and whose tissues were subjected to post-progression NGS were enrolled. The clinical characteristics, progression-free survival (PFS), genomic alterations and expression of EGFR-mutations among the three disease-progression modes were retrospectively analyzed.

RESULTS AND CONCLUSION

The sites of disease progression were as follows: primary foci in 19.5% (8/41) (Mode 1), metastatic foci in 31.7% (13/41) (Mode 2), and both primary and metastatic foci in 48.8% (20/41) (Mode 3). The median PFS in Mode 1 was 6 months (95% CI 1-8), which was significantly shorter than the 11 months (95% CI 8-14) in Mode 2 and the 10 months (95% CI 3-16) in Mode 3 (p = 0.0084). The expression of Del19 was significantly different among the three modes (p = 0.02). The numbers and species of mutant genes in Mode 3 were obviously greater than those in Modes 1 and 2, and no gene amplifications were observed in Mode 2. Mutations in the TP53 gene were the most frequent genetic alteration found in our study, and these accounted for 48.8% (20/41) of all alterations. TP53 mutations in Mode 1 were mainly in exons 6 and 8, while in Mode 2 and Mode 3, all mutations were located from exon 4 to exon 8. A significant benefit in PFS was observed in the metastatic foci progression mode and in the dual primary and metastatic foci progression mode rather than in the primary foci progression mode, which had significant value in the design of therapeutic strategies.

Increased glutamine anabolism sensitizes non-small cell lung cancer to gefitinib treatment

To better understand the resistance mechanism of non-small cell lung cancers (NSCLCs) to gefitinib, the metabolic profiles of gefitinib-resistant A549 cells and gefitinib-sensitive PC-9 cells were analyzed with a metabolomics analytical platform. A549 and PC-9 cells exhibited significant differences in the levels of glutamine-related metabolites. After gefitinib treatment, the glutamine level decreased in A549 cells but showed no change in PC-9 cells. The glutamine consumed by A549 cells was used to generate ATP and glutathione (GSH). As glutamine utilization was suppressed in gefitinib-treated PC-9 cells, the resulting ATP shortage and ROS accumulation led to cell death. The difference in glutamine metabolism was caused by differential changes in the levels of glutamine synthetase (GS, encoded by glutamate-ammonia ligase (GLUL)). GLUL expression was upregulated in gefitinib-sensitive cells, but it was either absent from gefitinib-resistant cells or no significant change was observed in the gefitinib-treated cells. GLUL overexpression in A549 cells significant sensitized them to gefitinib and decreased their invasive capacity. Conversely, knockout GS in PC-9 cells reduced gefitinib sensitivity and enhanced metastasis. Furthermore, the continuous exposure of gefitinib-sensitive HCC827 cells to gefitinib created gefitinib-resistant (GR) HCC827 cells, which exhibited a GLUL deletion and resistance to gefitinib. Thus, GLUL plays a vital role in determining the sensitivity of NSCLCs to gefitinib. Elevated GS levels mediate increased glutamine anabolism, and this novel mechanism sensitizes NSCLCs to gefitinib. The inhibition of glutamine utilization may serve as a potential therapeutic strategy to overcome gefitinib resistance in the clinic.

Cigarette smoke extract induces EGFR-TKI resistance via promoting EGFR signaling pathway and ROS generation in NSCLC cell lines

OBJECTIVES

Epithelial growth factor receptor (EGFR) somatic-mutated non-small cell lung cancer (NSCLC) patients with smoking history always show a poor response to EGFR tyrosine kinase inhibitors (EGFR-TKIs). The aim of the study is to explore the molecular mechanism of EGFR-TKI resistance induced by cigarette smoke extract and investigate the novel anti-resistance strategies.

METHODS

The effect of cigarette smoke extract (CSE) on gefitinib sensitivity, EGFR signaling, apoptosis and reactive oxygen species (ROS) levels were detected in vitro by MTT assays, western blot, flow cytometry and laser scanning confocal microscope, respectively.

RESULTS

MTT assays presented that CSE claimed antagonistic effect on gefitinib sensitivity via the up-regulated half maximal inhibitory concentration (IC50) values, western blot showed that CSE instigated EGFR, AKT phosphorylation, while N-Acetyl-l-Cysteine (NAC) could alleviate gefitinib resistance and abort the aberrant phosphorylation in both PC-9 and A549 cells. Confocal microscope and flow cytometry displayed that ROS generation increased after CSE exposure in NSCLC cells and this change could be inhibited by NAC.

CONCLUSION

Cigarette smoke extract induces EGFR-TKI resistance via promoting EGFR signaling and ROS generation in NSCLC cell lines which could be suppressed by NAC. Alternatively, combined NAC with EGFR-TKIs to treat EGFR mutated NSCLC patients with smoking history may be a potential choice in clinical setting.

Subsequent treatment of epidermal growth factor receptor-tyrosine kinase inhibitor failure in patients with advanced lung adenocarcinoma

BACKGROUND

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) effectively treat advanced non-small cell lung cancer with EGFR-mutation. However, most patients develop acquired resistance without effective therapy subsequent to EGFR-TKI failure. We evaluated the efficacy of subsequent treatment strategies for EGFR-TKI resistance.

METHODS

We retrospectively analyzed 240 patients with advanced lung adenocarcinoma with EGFR-TKI failure and following subsequent treatment. According to the first subsequent strategies after EGFR-TKI failure, patients were divided into groups of EGFR-TKI continuation (21 cases), EGFR-TKI continuation with chemotherapy (23 cases), chemotherapy alone (143 cases), and best supportive care (BSC) (53 cases).

RESULTS

Except for 53 cases of BSC, the disease control rates (DCR) of the remaining 187 patients in the EGFR-TKI continuation, EGFR-TKI continuation with chemotherapy, and chemotherapy alone groups were 66.7%, 73.9%, and 44.8%, respectively. The median post-progression progression-free survival (PFS) for the three groups was 3.0, 3.3, and 2.0 months, respectively. The DCR for the EGFR-TKI continuation with chemotherapy group was significantly higher than the chemotherapy alone group (P = 0.006). The post-progression PFS of the EGFR-TKI continuation with chemotherapy group was significantly longer than the chemotherapy alone group (P = 0.037). The median overall survival in the EGFR-TKI continuation, EGFR-TKI continuation with chemotherapy, chemotherapy alone, and BSC groups were 6.9, 11.6, 8.8, and 0.9 months, respectively. Compared to the BSC group, all groups achieved a survival benefit (P < 0.001).

CONCLUSIONS

EGFR-TKI continuation with chemotherapy could provide benefits for patients with acquired resistance to EGFR-TKI.

[Research Progress of Mechanisms on Intracranial Metastasis of Non-small Cell Lung Cancer after Clinical Benefit from EGFR-TKI]

表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitor, EGFR-TKI）广泛用于治疗EGFR突变阳性的非小细胞肺癌（non-small cell lung cancer, NSCLC）。然而，部分患者在接受EGFR-TKI治疗后、原发病灶稳定甚至缩小的同时，却出现了新发颅内转移灶或者原有颅内病灶进展，其机制未明。近年来多项研究表明，这种现象可能与EGFR-TKI的药物代谢动力学、NSCLC原发灶与转移灶的异质性、EGFR突变本身特质及患者生存期的延长有关。因此，本文就NSCLC患者在EGFR-TKI治疗临床获益后发生颅内转移的相关机制研究进展作一综述。