Rui Han

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality. Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are standard treatments for EML4-ALK-positive NSCLC, but resistance to these agents remains a challenge. This study aimed to determine the mechanisms of acquired resistance to the third-generation ALK-TKI lorlatinib. Lorlatinib-resistant cell lines were established by prolonged exposure to a high concentration of lorlatinib. Activation of epidermal growth factor receptor (EGFR) caused by a decrease in endocytosis and degradation of protein was demonstrated to play an essential role in acquired resistance to lorlatinib. The interaction between the EGFR and ALK was investigated to identify binding sites and conformational changes in ALK. We performed high-throughput compound screening using a small-molecule drugs library comprising 510 antitumor agents in an effort to discover small-molecule compounds that target EGFR in lorlatinib-resistant cells. Combination treatment with ALK-TKI and anti-EGFR agents suppressed acquired resistance to ALK-TKIs caused by activation of EGFR in vitro and in vivo, suggesting that the combination of lorlatinib and an anti-EGFR agent could be effective in patients with lorlatinib-resistant NSCLC. This research provides insights into the mechanism of resistance to lorlatinib and suggests that it can be overcome by anti-EGFR treatment, offering a promising approach for treating resistance to lorlatinib mediated by EGFR activation in patients with ALK-positive NSCLC.

Background The dynamic interplay between tyrosine kinase inhibitors (TKIs) and the tumor immune microenvironment (TME) plays a crucial role in the therapeutic trajectory of non-small cell lung cancer (NSCLC). Understanding the functional dynamics and resistance mechanisms of TKIs is essential for advancing the treatment of NSCLC. Methods This study assessed the effects of short-term and long-term TKI treatments on the TME in NSCLC, particularly targeting epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) mutations. We analyzed changes in immune cell composition, cytokine profiles, and key proteins involved in immune evasion, such as laminin subunit γ−2 (LAMC2). We also explored the use of aspirin as an adjunct therapy to modulate the TME and counteract TKI resistance. Results Short-term TKI treatment enhanced T cell-mediated tumor clearance, reduced immunosuppressive M2 macrophage infiltration, and downregulated LAMC2 expression. Conversely, long-term TKI treatment fostered an immunosuppressive TME, contributing to drug resistance and promoting immune escape. Differential responses were observed among various oncogenic mutations, with ALK-targeted therapies eliciting a stronger antitumor immune response compared with EGFR-targeted therapies. Notably, we found that aspirin has potential in overcoming TKI resistance by modulating the TME and enhancing T cell-mediated tumor clearance. Conclusions These findings offer new insights into the dynamics of TKI-induced changes in the TME, improving our understanding of NSCLC challenges. The study underscores the critical role of the TME in TKI resistance and suggests that adjunct therapies, like aspirin, may provide new strategies to enhance TKI efficacy and overcome resistance.

Numerous scattered case studies continue to demonstrate a strong correlation between acquired KRAS mutations and epidermal growth factor receptor-tyrosine kinase inhibitor resistance in non-small cell lung cancer. However, the comprehensive understanding of the KRAS pathway following the failure of epidermal growth factor receptor-tyrosine kinase inhibitor therapy remains limited. We conducted a retrospective evaluation of the next generation sequencing data from 323 patients with advanced non-small cell lung cancer and EGFR-activating mutations after experiencing progression with epidermal growth factor receptor-tyrosine kinase inhibitor therapy. Our analysis specifically focused on the acquired changes to the KRAS gene. Among the 323 patients with advanced non-small cell lung cancer and EGFR-activating mutations who experienced resistance to epidermal growth factor receptor-tyrosine kinase inhibitor therapy, 14 individuals (4.3%) developed resistance due to acquired KRAS alterations. Of these 14 patients, 10 cases (71.4%) were due to KRAS missense mutations, 1 case (7.2%) was due to KRAS gene fusion and 3 cases (21.4%) were due to KRAS amplification. Notably, we identified one newly demonstrated KRAS gene fusion (KRAS and LMNTD1), one KRAS G13D and one KRAS K117N. The emergence of acquired KRAS alterations was often accompanied by novel mutations and high tumor mutation burden, with TP53, CNKN2A, PIK3CA, MYC, STK11, CDK4, BRCA2 and ERBB2 being the most frequently observed concurrent mutations. The median progression-free survival and overall survival for the 14 patients were 5.2 and 7.3 months, respectively. Acquired KRAS missense variants were associated with significantly worse progression-free survival compared with other KRAS variant subtypes (P < 0.028). This study provides significant evidence of the role of acquired KRAS variants in the development of resistance to epidermal growth factor receptor-tyrosine kinase inhibitor therapy. Our results contribute to the growing body of knowledge on the mutational profiles associated with resistance to epidermal growth factor receptor-tyrosine kinase inhibitor treatment. Furthermore, our study highlights the KRAS gene change as a significant mechanism of resistance to epidermal growth factor receptor-tyrosine kinase inhibitor therapy.

Background: Circulating tumor DNA (ctDNA) has made a breakthrough as an early biomarker in operable early‐stage cancer patients. However, the function of ctDNA combined with cell‐free DNA (cfDNA) as a predictor in advanced non‐small cell lung cancer (NSCLC) remains unknown. Here, we explored its potential as a biomarker for predicting the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) in patients with advanced NSCLC.Methods: A retrospective analysis was undertaken. Plasma collected from 51 patients with advanced NSCLC prior to and serially after starting treatment with EGFR‐TKIs was analyzed by next‐generation sequencing (NGS). The performance of ctDNA, cfDNA, and combining ctDNA with cfDNA were evaluated for their ability to predict survival outcomes.Results: Patients with early undetectable ctDNA and increasing cfDNA had a markedly better progression‐free survival (PFS) (p < 0.001) and overall survival (OS) (p = 0.001) than those with early detectable ctDNA and decreasing cfDNA. Patients with early ctDNA clearance were more likely to have the ctDNA persistent clearance (p = 0.006). The early clearance rate of ctDNA in the normal carcinoembryonic antigen (CEA) group was significantly higher than in the low and high groups (p = 0.028). Patients with greater CEA decline had a higher early clearance rate of ctDNA than those with minor CEA change (p = 0.016).Conclusions: We based this study on ctDNA and cfDNA, explored its prognostic predictive ability, and combined CEA to monitor EGFR‐TKI efficacy. This study may provide new perspectives and insights into the precise treatment strategies for NSCLC patients.

Lorlatinib is a promising third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI) that has been approved for treating ALK-positive non-small-cell lung cancer (NSCLC) patients with previous ALK-TKI treatment failures. However, the inevitable emergence of acquired resistance limits its long-term efficacy. A more comprehensive understanding of the acquired resistance mechanisms to lorlatinib will enable the development of more efficacious therapeutic strategies. The efficacy of chloroquine (CQ) in combination with lorlatinib in ALK-positive NSCLC cells in vitro and in vivo was assessed using CCK-8, colony formation, immunofluorescence staining, flow cytometry analysis, western blot analysis, and xenograft implantation. Here, we show that lorlatinib induced apoptosis and protective autophagy in ALK-positive NSCLC cells. However, the protective autophagy can gradually lead to decreased cytotoxicity of loratinib in ALK-positive NSCLC cells. Meanwhile, we found that the combination of lorlatinib and CQ, an inhibitor of autophagy, inhibited autophagy and promoted apoptosis both in vitro and in vivo, which sensitized cells to lorlatinib through the dephosphorylation of Foxo3a and promoted nuclear translocation, then activation of Foxo3a/Bim axis. Taken together, our results suggest that inhibition of protective autophagy might be a therapeutic target for delaying the occurrence of acquired resistance to lorlatinib in ALK-positive NSCLC patients.

Osimertinib, a third‐generation irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR‐TKI), provides marked clinical benefit for patients with EGFR‐activating mutations. Unfortunately, limited treatments exist for patients who acquire osimertinib resistance. We observed two ‘special’ patients who regained an antitumor response with osimertinib plus aspirin treatment. As previous data indicate that aspirin induces antiproliferative effects in tumor cells, we designed a preclinical study to explore whether aspirin combined with osimertinib could synergistically sensitize osimertinib‐resistant non‐small‐cell lung cancer (NSCLC) cells. The effects of combined treatment with osimertinib and aspirin on osimertinib‐resistant NSCLC cell lines were examined in vitro and in vivo. The combination of osimertinib and aspirin induced strong antiproliferative and proapoptotic effects in osimertinib‐resistant NSCLC cells through inhibition of Akt/FoxO3a signaling component phosphorylation and increased Bim expression. Furthermore, Bim knockdown by siRNA significantly attenuated osimertinib resensitization by aspirin. In vivo, combination of aspirin and osimertinib significantly decreased tumor growth of PC‐9GROR cell xenografts. Data of patients with NSCLC who received osimertinib treatment at Daping Hospital between January 2015 and January 2019 were reviewed retrospectively. According to clinical data for 45 patients with NSCLC, retrospective analysis showed that the median progression‐free survival was significantly longer in the osimertinib plus aspirin group than in the osimertinib group. In summary, aspirin synergistically enhances the antitumor activity of osimertinib in osimertinib‐resistant lung cancer cells through promoting Bim‐dependent apoptosis. This combination therapy may be effective in overcoming acquired resistance to osimertinib and prolonging survival in patients with NSCLC.

Alectinib is a second-generation anaplastic lymphoma kinase (ALK) inhibitor that has sufficient clinical efficacy and satisfactory safety in ALK-positive non-small cell lung cancer (NSCLC) patients with or without brain metastasis. Alectinib has now become an important drug in the first-line treatment of advanced ALK-positive NSCLC; however, resistance is almost inevitable. The increased expression of hepatocyte growth factor (HGF) and its physiological receptor tyrosine kinase MET have been shown to be linked to acquired resistance to various tyrosine kinase inhibitors (TKIs), and this phenomenon has been observed in some ALK-positive NSCLC tumour tissues. In this study, we found that HGF levels in the culture supernatant of an ALK-positive cell line tended to increase with time and could be further increased by alectinib in a time-dependent manner. Exogenous or endogenous HGF did not cause resistance to the ALK/MET double-targeted small molecule inhibitor crizotinib, but it was an important cause of alectinib resistance. Furthermore, Gab1 was a key effector in the HGF/MET signal transduction pathway that mediated alectinib resistance. The antidiabetic drug metformin combined with alectinib overcame alectinib resistance triggered by HGF/MET through disrupting the complex between MET and Gab1, thereby inhibiting Gab1 phosphorylation and the activation of downstream signal transduction pathways. These results suggest that metformin combined with alectinib may be useful for overcoming alectinib resistance induced by the activation of the HGF/MET signalling pathway and improving the efficacy of alectinib.

Metformin restores crizotinib sensitivity in crizotinib-resistant human lung cancer cells through inhibition of IGF1-R signaling pathway

Salvia miltiorrhiza is a traditional Chinese medicine which has been well documented for its anti-cancer effects. Based on the structure of danshinone, one of the active compounds derived from Salvia miltiorrhiza, we synthesized a simplified phenolic analog, S-3-1, and tried to explore its possible actions in preventing the development of cancer. With the Ames test, S-3-1 was found to efficiently suppress the mutagenicity of benzo[α]pyrene. This result is consistent with the inhibitory effect of S-3-1 on the activation of benzo[α]pyrene by hepatic microsomal enzymes. Besides the anti-initiation effects, S-3-1 could significantly inhibit the croton oil-induced increase of mouse skin epithermal ornithine decarboxylase activity. Moreover, S-3-1 quenched both superoxide and hydroxyl free radicals whereas it inhibited lipid peroxidation in the in vitro model. These results suggest that S-3-1 might act as anti-initiation and anti-promotion agents through reversing the biochemical alterations induced by carcinogen during carcinogenesis. Therefore, we further investigated the effects of S-3-1 on carcinogenesis. In vitro, S-3-1 inhibited the benzo[α]pyrene-induced transformation of V79 Chinese hamster lung fibroblasts. At 10-40 mg/kg, S-3-1 was found to inhibit the development of DMBA/croton oil-induced skin papilloma in mice through decreasing the incidence of papilloma, prolonging the latent period of tumor occurrence and reducing tumor number per mouse in a dose-dependent manner. We concluded from this study that S-3-1 might be developed as a new chemopreventive drug.