• Tuberculosis and Respiratory Diseases
• /
• 제80권2호
• /
• pp.187-193
• /
• 2017

Background: Third-generation tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKIs) have proved efficacious in treating non-small cell lung cancer (NSCLC) patients with acquired resistance resulting from the T790M mutation. However, since almost 50% patients with the acquired resistance do not harbor the T790M mutation, retreatment with first- or second-generation EGFR-TKIs may be a more viable therapeutic option. Here, we identified positive response predictors to retreatment, in patients who switched to a different EGFR-TKI, following initial treatment failure. Methods: This study retrospectively reviewed the medical records of 42 NSCLC patients with EGFR mutations, whose cancers had progressed following initial treatment with gefitinib or erlotinib, and who had switched to a different first-generation EGFR-TKI during subsequent retreatment. To identify high response rate predictors in the changed EGFR-TKI retreatment, we analyzed the relationship between clinical and demographic parameters, and positive clinical outcomes, following retreatment with EGFR-TKI. Results: Overall, 30 (71.4%) patients received gefitinib and 12 (28.6%) patients received erlotinib as their first EGFR-TKI treatment. Following retreatment with a different EGFR-TKI, the overall response and disease control rates were 21.4% and 64.3%, respectively. There was no significant association between their overall responses. The median progression-free survival (PFS) after retreatment was 2.0 months. However, PFS was significantly longer in patients whose time to progression was ${\geq}10months$ following initial EGFR-TKI treatment, who had a mutation of exon 19, or whose treatment interval was <90 days. Conclusion: In patients with acquired resistance to initial EGFR-TKI therapy, switched EGFR-TKI retreatment may be a salvage therapy for individuals possessing positive retreatment response predictors.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권1호
• /
• pp.205-213
• /
• 2014

The outcomes of first-generation EGFR-TKIs (Gefitnib and Erlotinib) have shown great advantages over traditional treatment strategies in patients with non-small cell lung cancer (NSCLC), but unfortunately we have to face the situation that most patients still fail to respond in the long term despite initially good control. Up to now, the mechanism of acquired resistance to EGFR-TKIs has not been fully clarified. Herein, we sought to compile the available clinical reports in the hope to better understanding the subsequent treatment choices, particularly on whether restoring after a drug holiday or switching to another EGFR-TKI is the better option after failure of one kind of EGFR-TKI.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권7호
• /
• pp.2915-2921
• /
• 2015

Background: Some recent clinical trials have been conducted to evaluate a combination of EGFR- TKI with chemotherapy for advanced NSCLC patients as second-line therapy, but the results on the efficacy of such trials are inconsistent. The aim of this meta-analysis was to evaluate the efficacy and safety of combination of EGFR-TKI and chemotherapy for patients with advanced NSCLC who failed first-line treatment. Materials and Methods: We searched relative trials from PubMed, EMBASE, ASCO Abstracts, ESMO Abstracts, Cochrane Library and Clinical Trials.gov. Outcomes analyzed were overall response rate (ORR), progression- free survival (PFS), overall survival (OS) and major toxicity. Results: Seven trails eventually were included in this meta-analysis, covering 1,168 patients. The results showed that the combined regimen arm had a significant higher ORR (RR 1.76 [1.16, 2.66], p=0.007) and longer PFS (HR 0.75 [0.66-0.85], p<0.00001), but failed to show effects on OS (HR 0.88 [0.68-1.15], p=0.36). In terms of subgroup results, continuation of EGFR-TKI in addition to chemotherapy after first-line EGFR-TKI resistance confered no improvement in ORR (RR 0.95 [0.68, 1.33], p=0.75) and PFS (HR 0.89[0.69, 1.15], p=0.38), and OS was even shorter (HR1.52 [1.05-2.21], p=0.03). However, combination therapy with EGFR-TKI and chemotherapy after failure of first-line chemotherapy significantly improved the ORR (RR 2.06 [1.42, 2.99], p=0.0002), PFS (HR 0.71 [0.61, 0.82], p<0.00001) and OS (HR 0.74 [0.62-0.88], p=0.0008), clinical benefit being restricted to combining EGFR-TKI with pemetrexed, but not docetaxel. Grade 3-4 toxicity was found at significantly higher incidence in the combined regimen arm. Conclusions: Continuation of EGFR-TKI in addition to chemotherapy after first-line EGFR-TKI resistance should be avoided. Combination therapy of EGFR-TKI and pemetrexed for advanced NSCLC should be further investigated for prognostic and predictive factors to find the group with the highest benefit of the combination strategy.

• Tuberculosis and Respiratory Diseases
• /
• 제71권4호
• /
• pp.286-290
• /
• 2011

Although failure of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKI) is generally believed to be associated with cross-resistance to other EGFR TKI, the benefit of administering erlotinib as a second EGFR TKI after resistance of gefitinib as the first TKI has been well known. However, good response to gefitinib after an initial response to erlotinib has been rare. We report that a 45-year-old woman (never smoked), with lung adenocarcinoma and EGFR mutation, showed an initial response to erlotinib, and then responded to gefitinib again.

• International Journal of Oncology
• /
• 제56권6호
• /
• pp.1540-1550
• /
• 2020

The epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), gefitinib, is an effective therapeutic drug used in the treatment of non-small cell lung cancers (NSCLCs) harboring EGFR mutations. However, acquired resistance significantly limits the efficacy of EGFR-TKIs and consequently, the current chemotherapeutic strategies for NSCLCs. It is, therefore, necessary to overcome this resistance. In the present study, the anticancer potential of natural extracts of Coptis chinensis (ECC) against gefitinib-resistant (GR) NSCLC cells were investigated in vitro and in vivo. ECC inhibited the viability, migration and invasion, and effectively induced the apoptosis of GR cells. These effects were associated with the suppression of EGFR/AKT signaling and the expression of anti-apoptotic proteins, Mcl-1 and Bcl-2, which were overexpressed in GR NSCLC cells. Combination treatment with ECC and gefitinib enhanced the sensitivity of GR cells to gefitinib in vitro, but not in vivo. However, ECC increased the survival of individual zebrafish without affecting the anticancer effect to cancer cells in vivo, which indicated a specific cytotoxic effect of ECC on cancer cells, but not on normal cells; this is an important property for the development of novel anticancer drugs. On the whole, the findings of the present study indicate the potential of ECC for use in the treatment of NSCLC, particularly in combination with EGFR-TKI therapy, in EGFR-TKI-resistant cancers.

• 동의생리병리학회지
• /
• 제35권4호
• /
• pp.117-123
• /
• 2021

Gefitinib, a first generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), provides obvious clinical benefit in patients with EGFR-mutant non-small cell lung cancer (NSCLC). However, patients ultimately develop gefitinib resistance which mainly caused by EGFR T790M secondary mutation. In the current study, we investigated whether the root extract of Scutellaria baicalensis (SB) overcomes gefitinib resistance. Gefitinib-resistant H1975 human NSCLC cells (EGFR L858R/T790M double mutant) were treated with gefitinib and/or ethanol extract of SB (ESB) to evaluate the effect of ESB on the gefitinib sensitivity. The cell viability was measured by MTT assay and trypan blue exclusion assay. The colony-forming ability was evaluated by anchorage-dependent colony formation assay. Combined treatment with gefitinib and ESB markedly decreased the cell viability and colony formation than single treatment with gefitinib or ESB in H1975 cells. In addition, cells treated with both gefitinib and ESB exhibited a significant increase of sub-G1 DNA content which indicates apoptotic cells compared with those treated with gefitinib or ESB alone. As a molecular mechanism, combined treatment with gefitinib and ESB strongly downregulated the phosphorylation of ERK and JNK than single treatment with gefitinib or ESB. Taken together, our results demonstrate that ESB sensitizes H1975 cells to gefitinib treatment. We cautiously propose that ESB can be used in combination with gefitinib for the advanced NSCLC patients with acquired resistance to EGFR TKIs.

• Journal of Microbiology and Biotechnology
• /
• 제31권4호
• /
• pp.559-569
• /
• 2021

As one of the major types of lung cancer, non-small cell lung cancer (NSCLC) accounts for the majority of cancer-related deaths worldwide. Treatments for NSCLC includes surgery, chemotherapy, and targeted therapy. Among the targeted therapies, resistance to inhibitors of the epidermal growth factor receptor (EGFR) is common and remains a problem to be solved. MET (hepatocyte growth factor receptor) amplification is one of the major causes of EGFR-tyrosine kinase inhibitor (TKI) resistance. Therefore, there exists a need to find new and more efficacious therapies. Deoxypodophyllotoxin (DPT) extracted from Anthriscus sylvestris roots exhibits various pharmacological activities including anti-inflammation and anti-cancer effects. In this study we sought to determine the anti-cancer effects of DPT on HCC827GR cells, which are resistant to gefitinib (EGFR-TKI) due to regulation of EGFR and MET and their related signaling pathways. To identify the direct binding of DPT to EGFR and MET, we performed pull-down, ATP-binding, and kinase assays. DPT exhibited competitive binding with ATP against the network kinases EGFR and MET and reduced their activities. Also, DPT suppressed the expression of p-EGFR and p-MET as well as their downstreat proteins p-ErbB3, p-AKT, and p-ERK. The treatment of HCC827GR cells with DPT induced high ROS generation that led to endoplasmic-reticulum stress. Accordingly, loss of mitochondrial membrane potential and apoptosis by multi-caspase activation were observed. In conclusion, these results demonstrate the apoptotic effects of DPT on HCC827GR cells and signify the potential of DPT to serve as an adjuvant anti-cancer drug by simultaneously inhibiting EGFR and MET.

• International Journal of Oncology
• /
• 제55권1호
• /
• pp.320-330
• /
• 2019

The aim of this study was to investigate the underlying mechanisms responsible for the anticancer effects of lupeol on human non-small cell lung cancer (NSCLC). MTT assay and Trypan blue exclusion assay were used to evaluate the cell viability. DAPI staining and flow cytometric analysis were used to detect apoptosis. Molecular docking and western blot analysis were performed to determine the target of lupeol. We found that lupeol suppressed the proliferation and colony formation of NSCLC cells in a dose-dependent manner. In addition, lupeol increased chromatin condensation, poly(ADP-ribose) polymerase (PARP) cleavage, sub-G1 cell populations, and the proportion of Annexin V-positive cells, indicating that lupeol triggered the apoptosis of NSCLC cells. Notably, lupeol inhibited the phosphorylation of epithelial growth factor receptor (EGFR). A docking experiment revealed that lupeol directly bound to the tyrosine kinase domain of EGFR. We observed that the signal transducer and activator of transcription 3 (STAT3), a downstream molecule of EGFR, was also dephosphorylated by lupeol. Lupeol suppressed the nuclear translocation and transcriptional activity of STAT3 and downregulated the expression of STAT3 target genes. The constitutive activation of STAT3 by STAT3 Y705D overexpression suppressed lupeol-induced apoptosis, demonstrating that the inhibition of STAT3 activity contributed to the induction of apoptosis. The anticancer effects of lupeol were consistently observed in EGFR tyrosine kinase inhibitor (TKI)-resistant H1975 cells (EGFR L858R/T790M). Taken together, the findings of this study suggest that lupeol may be used, not only for EGFR TKI-naïve NSCLC, but also for advanced NSCLC with acquired resistance to EGFR TKIs.

• Tuberculosis and Respiratory Diseases
• /
• 제75권3호
• /
• pp.95-103
• /
• 2013

Background: Small cell lung cancer (SCLC) transformation during epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment in lung cancer has been suggested as one of possible resistance mechanisms. Methods: We evaluated whether SCLC transformation or neuroendocrine (NE) differentiation can be found in the cell line model. In addition, we also investigated its effect on responses to conventional chemotherapeutic drugs of the SCLC treatment. Results: Resistant cell lines to various kinds of EGFR-TKIs such as gefitinib, erlotinib, CL-387,785 and ZD6474 with A549, PC-9 and HCC827 lung adenocarcinoma cell lines were established. Among them, two resistant cell lines, A549/GR (resistant to gefitinib) and PC-9/ZDR (resistant to ZD6474) showed increased expressions of CD56 while increased synaptophysin, Rb, p16 and poly(ADP-ribose) polymerase were found only in A549/GR in western blotting, suggesting that NE differentiation occurred in A549/GR. A549/GR cells were more sensitive to etoposide and cisplatin, chemotherapeutic drugs for SCLC, compared to parental cells. Treatment with cAMP and IBMX induced synaptophysin and chromogranin A expression in A549 cells, which also made them more sensitive to etoposide and cisplatin than parental cells. Furthermore, we found a tissue sample from a patient which showed increased expressions of CD56 and synaptophysin after development of resistance to erlotinib. Conclusion: NE differentiation can occur during acquisition of resistance to EGFR-TKI, leading to increased chemosensitivity.

• Tuberculosis and Respiratory Diseases
• /
• 제74권3호
• /
• pp.129-133
• /
• 2013

The presence of epidermal growth factor receptor (EGFR ) mutation is a prognostic and predictive marker for EGFR-tyrosine kinase inhibitor (TKI) therapy. However, inevitably, relapse occurs due to the development of acquired resistance, such as T790M mutation. We report a case of repeated responses to EGFR-TKIs in a never-smoked woman with adenocarcinoma. After six cycles of gemcitabine and cisplatin, the patient was treated by gefitinib for 4 months until progression. Following the six cycles of third-line pemetrexed, gefitinib retreatment was initiated and continued with a partial response for 6 months. After progression, she was recruited for an irreversible EGFR inhibitor trial, and the time to progression was 11 months. Although EGFR direct sequencing on the initial diagnostic specimen revealed a wild-type, we performed a rebiopsy from the progressed subcarinal node at the end of the trial. The result of peptide nucleic acid clamping showed L858R/L861Q.