Therapeutic strategies to overcome crizotinib resistance in non-small cell lung cancers harboring the fusion oncogene EML4-ALK.
ABSTRACT: The echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion oncogene represents a molecular target in a small subset of non-small cell lung cancers (NSCLCs). This fusion leads to constitutive ALK activation with potent transforming activity. In a pivotal phase 1 clinical trial, the ALK tyrosine kinase inhibitor (TKI) crizotinib (PF-02341066) demonstrated impressive antitumor activity in the majority of patients with NSCLC harboring ALK fusions. However, despite these remarkable initial responses, cancers eventually develop resistance to crizotinib, usually within 1 y, thereby limiting the potential clinical benefit. To determine how cancers acquire resistance to ALK inhibitors, we established a model of acquired resistance to crizotinib by exposing a highly sensitive EML4-ALK-positive NSCLC cell line to increasing doses of crizotinib until resistance emerged. We found that cells resistant to intermediate doses of crizotinib developed amplification of the EML4-ALK gene. Cells resistant to higher doses (1 ?M) also developed a gatekeeper mutation, L1196M, within the kinase domain, rendering EML4-ALK insensitive to crizotinib. This gatekeeper mutation was readily detected using a unique and highly sensitive allele-specific PCR assay. Although crizotinib was ineffectual against EML4-ALK harboring the gatekeeper mutation, we observed that two structurally different ALK inhibitors, NVP-TAE684 and AP26113, were highly active against the resistant cancer cells in vitro and in vivo. Furthermore, these resistant cells remained highly sensitive to the Hsp90 inhibitor 17-AAG. Thus, we have developed a model of acquired resistance to ALK inhibitors and have shown that second-generation ALK TKIs or Hsp90 inhibitors are effective in treating crizotinib-resistant tumors harboring secondary gatekeeper mutations.
Project description:To extend the results of a phase III trial in patients with non-small cell lung cancer with adenocarcinomas harboring EML4-ALK fusion.We conducted a co-clinical trial in a mouse model comparing the ALK inhibitor crizotinib to the standard-of-care cytotoxic agents docetaxel or pemetrexed.Concordant with the clinical outcome in humans, crizotinib produced a substantially higher response rate compared with chemotherapy, associated with significantly longer progression-free survival. Overall survival was also prolonged in crizotinib- compared with chemotherapy-treated mice. Pemetrexed produced superior overall survival compared with docetaxel, suggesting that this agent may be the preferred chemotherapy in the ALK population. In addition, in the EML4-ALK-driven mouse lung adenocarcinoma model, HSP90 inhibition can overcome both primary and acquired crizotinib resistance. Furthermore, HSP90 inhibition, as well as the second-generation ALK inhibitor TAE684, demonstrated activity in newly developed lung adenocarcinoma models driven by crizotinib-insensitive EML4-ALK L1196M or F1174L.Our findings suggest that crizotinib is superior to standard chemotherapy in ALK inhibitor-naïve disease and support further clinical investigation of HSP90 inhibitors and second-generation ALK inhibitors in tumors with primary or acquired crizotinib resistance.
Project description:The discovery of an echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion gene led to improved clinical outcomes in patients with lung cancer after the development of the first ALK-targeting agent, crizotinib. Some second-generation ALK tyrosine kinase inhibitors (TKIs), which might be more potent than crizotinib or effective on crizotinib-resistant patients, have been developed. Although these ALK-TKIs show an excellent response initially, most patients eventually acquire resistance. Therefore, careful consideration of the resistance mechanisms might lead to superior therapeutic strategies. Here, we summarize the history of ALK-TKIs and their underlying resistance mechanisms in both the preclinical and clinical settings. In addition, we discuss potential future treatment strategies in ALK-TKI-naïve and -resistant patients with lung cancer harboring the EML4-ALK fusion gene.
Project description:Rearrangements in anaplastic lymphoma kinase (ALK) gene and echinoderm microtubule-associated protein-like 4 (EML4) gene were first described in a small portion of patients with non-small cell lung cancer (NSCLC) in 2007. Fluorescence in situ hybridization is used as the diagnostic test for detecting an EML4-ALK rearrangement. Crizotinib, an ALK inhibitor, is effective in treating advanced ALK-positive NSCLC, and the US Food and Drug Administration approved it for treating ALK-positive NSCLC in 2011. Several mechanisms of acquired resistance to crizotinib have recently been reported. Second-generation ALK inhibitors were designed to overcome these resistance mechanisms. Two of them, ceritinib and alectinib, were approved in 2014 for advanced ALK-positive NSCLC in the US and Japan, respectively. Heat shock protein 90 (Hsp90) inhibitors also showed activity against ALK-positive NSCLC. Here we review the recent development of crizotinib, ceritinib, alectinib and other second-generation ALK inhibitors as well as Hsp90 inhibitors. We also discuss management strategies for advanced ALK-positive NSCLC.
Project description:Epithelial-mesenchymal transition (EMT) is associated with reduced sensitivity to many chemotherapeutic drugs, including EGFR tyrosine kinase inhibitors. Here, we investigated if this reduced sensitivity also contributes to resistance to crizotinib, an ALK inhibitor of lung cancer that exhibits the EML4-ALK translocation. We established a crizotinib-resistant subline (H2228/CR), which was derived from the parental H2228 cell line by long-term exposure to increasing concentrations of crizotinib. Characteristics associated with EMT, including morphology, EMT marker proteins, and cellular mobility, were analyzed. Compared with H2228 cells, the growth of H2228/CR cells was independent of EML4-ALK, and H2228/CR cells showed cross-resistance to TAE-684 (a second-generation ALK inhibitor). Phenotypic changes to the spindle-cell shape were noted in H2228/CR cells, which were accompanied by a decrease in E-cadherin and increase in vimentin and AXL. In addition, H2228/CR cells showed increased secretion and expression of TGF-?1. Invasion and migration capabilities were dramatically increased in H2228/CR cells. Applying TGF-?1 treatment to parental H2228 cells for 72 h induced reversible EMT, leading to crizotinib resistance, but this was reversed by the removal of TGF-?1. Suppression of vimentin in H2228/CR cells by siRNA treatment restored sensitivity to crizotinib. Furthermore, these resistant cells remained highly sensitive to the Hsp90 inhibitors, similar to the parental H2228 cells. In conclusion, we suggest EMT is possibly involved in acquired resistance to crizotinib, and that HSP90 inhibitors could be a promising option for the treatment of EMT.
Project description:Crizotinib is the first anaplastic lymphoma kinase (ALK) inhibitor to have been approved for the treatment of non-small cell lung cancer (NSCLC) harboring an ALK fusion gene, but it has been found that, in the clinic, patients develop resistance to it. Alectinib and ceritinib are second-generation ALK inhibitors which show remarkable clinical responses in both crizotinib-naive and crizotinib-resistant NSCLC patients harboring an ALK fusion gene. Despite their impressive activity, clinical resistance to alectinib and ceritinib has also emerged. In the current study, we elucidated the resistance mechanisms to these second-generation ALK inhibitors in the H3122 NSCLC cell line harboring the EML4-ALK variant 1 fusion in vitro. Prolonged treatment of the parental H3122 cells with alectinib and ceritinib led to two cell lines which are 10 times less sensitive to alectinib and ceritinib than the parental H3122 cell line. Although mutations of ALK in its kinase domain are a common resistance mechanism for crizotinib, we did not detect any ALK mutation in these resistant cell lines. Rather, overexpression of phospho-ALK and alternative receptor tyrosine kinases such as phospho-EGFR, phospho-HER3, and phospho-IGFR-1R was observed in both resistant cell lines. Additionally, NRG1, a ligand for HER3, is upregulated and responsible for resistance by activating the EGFR family pathways through the NRG1-HER3-EGFR axis. Combination treatment with EGFR inhibitors, in particular afatinib, was shown to be effective at overcoming resistance. Our study provides new mechanistic insights into adaptive resistance to second-generation ALK inhibitors and suggests a potential clinical strategy to combat resistance to these second-generation ALK inhibitors in NSCLC.
Project description:Alectinib is a new generation ALK inhibitor with activity against the gatekeeper L1196M mutation that showed remarkable activity in a phase I/II study with echinoderm microtubule associated protein-like 4 (EML4)--anaplastic lymphoma kinase (ALK) non-small cell lung cancer (NSCLC) patients. However, alectinib resistance may eventually develop. Here, we found that EGFR ligands and HGF, a ligand of the MET receptor, activate EGFR and MET, respectively, as alternative pathways, and thereby induce resistance to alectinib. Additionally, the heat shock protein 90 (Hsp90) inhibitor suppressed protein expression of ALK, MET, EGFR, and AKT, and thereby induced apoptosis in EML4-ALK NSCLC cells, even in the presence of EGFR ligands or HGF. These results suggest that Hsp90 inhibitors may overcome ligand-triggered resistance to new generation ALK inhibitors and may result in more successful treatment of NSCLC patients with EML4-ALK.
Project description:EML4-ALK gene rearrangements define a unique subset of patients with non-small cell lung carcinoma (NSCLC), and the clinical success of the anaplastic lymphoma kinase (ALK) inhibitor crizotinib in this population has become a paradigm for molecularly targeted therapy. Here, we show that the Hsp90 inhibitor ganetespib induced loss of EML4-ALK expression and depletion of multiple oncogenic signaling proteins in ALK-driven NSCLC cells, leading to greater in vitro potency, superior antitumor efficacy, and prolonged animal survival compared with results obtained with crizotinib. In addition, combinatorial benefit was seen when ganetespib was used with other targeted ALK agents both in vitro and in vivo. Importantly, ganetespib overcame multiple forms of crizotinib resistance, including secondary ALK mutations, consistent with activity seen in a patient with crizotinib-resistant NSCLC. Cancer cells driven by ALK amplification and oncogenic rearrangements of ROS1 and RET kinase genes were also sensitive to ganetespib exposure. Taken together, these results highlight the therapeutic potential of ganetespib for ALK-driven NSCLC.In addition to direct kinase inhibition, pharmacologic blockade of the molecular chaperone Hsp90 is emerging as a promising approach for treating tumors driven by oncogenic rearrangements of ALK. The bioactivity profi le of ganetespib presented here underscores a new therapeutic opportunity to target ALK and overcome multiple mechanisms of resistance in patients with ALK-positive NSCLC.
Project description:Identification of activating mutations in non-small cell lung cancers (NSCLC) has been a focus in recent years. This led to successful evidence of using tyrosine kinase inhibitors (TKIs) over the standard platinum doublet based chemotherapy as the first line treatment in the metastatic setting.The rearrangements of fusion protein EML4-ALK in NSCLC lead to the use of crizotinib for this class of tumors. Preclinical and Phase 1 clinical studies show that ceritinib is more effective against both crizotinib sensitive and resistant tumors. Although robust responses to crizotinib are observed in NSCLC harboring ALK mutations, majority of tumors eventually become resistant, posing a major challenge in treatment course. Thus, there is a need for the identification and development of second-generation of ALK inhibitors. Computer aided molecular docking data show Tivozanib and Lapatinib bind EML4-ALK with high score. Tivozanib is in clinical trials for renal cell cancer and Lapatinib is a known dual tyrosine kinase inhibitor effective in breast cancer patients with HER2 over-expression. Additional data on these compounds for use in EML4-ALK positive NSCLC will provide evidence for use in patients treated with crizotinib. Data shows the importance of computer aided molecular docking in developing candidates with improved activity for further consideration in vitro and in vivo validation.
Project description:ALK is involved in the onset of several tumors. Crizotinib (XalkoriTM), a potent ALK inhibitor, represents the current front-line treatment for ALK+ NSCLC and shows great clinical efficacy. However, resistant disease often develops after initial response. ASP3026 is a novel second-generation ALK inhibitor with activity on crizotinib-resistant ALK-L1196M gatekeeper mutant. As resistance is likely to be a relevant hurdle for any drug, we sought to determine the resistance profile of ASP3026 in the context of NPM/ALK+ ALCL. We selected six ASP3026-resistant cell lines by culturing human ALCL cells in the presence of increasing concentrations of drug. The established resistant cell lines carry several point mutations in the ALK kinase domain (G1128S, C1156F, I1171N/T, F1174I, N1178H, E1210K and C1156F/D1203N were the most frequent) that are shown to confer resistance to ASP3026 in the Ba/F3 cell model. All mutants were profiled for cross-resistance against a panel of clinically relevant inhibitors including ceritinib, alectinib, crizotinib, AP26113 and PF-06463922. Finally, a genetically heterogeneous ASP3026-resistant cell line was exposed to second-line treatment simulations with all inhibitors. The population evolved according to relative sensitivity of its mutant subclones to the various drugs. Compound PF-06463922 did not allow the outgrowth of any resistant clone, at non-toxic doses.