Dramatic response to crizotinib through MET phosphorylation inhibition in rare TFG-MET fusion advanced squamous cell lung cancer.

With the widespread use of next-generation sequencing (NGS) for solid tumors, mesenchymal-to-epithelial transition factor (MET) rearrangement/fusion has been confirmed in multiple cancer types. MET amplification and MET exon 14 skipping mutations induce protein autophosphorylation; however, the pathogenic mechanism and drug sensitivity of MET fusion remain unclear. The following report describes the clinical case of a patient diagnosed with squamous lung cancer bearing a TFG-MET gene fusion. In vitro assays demonstrated MET phosphorylation and oncogenic capacity due to the TFG-MET rearrangement, both of which were inhibited by crizotinib treatment. The patient was treated with crizotinib, which resulted in sustained partial remission for more than 17 months. Collectively, cellular analyses and our case report emphasize the potential of MET fusion as a predictive biomarker for personalized target therapy for solid tumors.

A benchmarking framework for the accurate and cost-effective detection of clinically-relevant structural variants for cancer target identification and diagnosis.

BACKGROUND: Accurate clinical structural variant (SV) calling is essential for cancer target identification and diagnosis but has been historically challenging due to the lack of ground truth for clinical specimens. Meanwhile, reduced clinical-testing cost is the key to the widespread clinical utility. METHODS: We analyzed massive data from tumor samples of 476 patients and developed a computational framework for accurate and cost-effective detection of clinically-relevant SVs. In addition, standard materials and classical experiments including immunohistochemistry and/or fluorescence in situ hybridization were used to validate the developed computational framework. RESULTS: We systematically evaluated the common algorithms for SV detection and established an expert-reviewed SV call set of 1,303 tumor-specific SVs with high-evidence levels. Moreover, we developed a random-forest-based decision model to improve the true positive of SVs. To independently validate the tailored 'two-step' strategy, we utilized standard materials and classical experiments. The accuracy of the model was over 90% (92-99.78%) for all types of data. CONCLUSION: Our study provides a valuable resource and an actionable guide to improve cancer-specific SV detection accuracy and clinical applicability.

High-dose furmonertinib combined with intraventricular chemotherapy as salvage therapy for leptomeningeal metastasis from EGFR exon 20 insertion-mutated lung cancer.

PURPOSE: The treatment of leptomeningeal metastasis (LM), a serious complication of advanced non-small cell lung cancer (NSCLC), presents challenges, particularly in patients with EGFR exon 20 insertion (ex20ins) mutations. METHODS: This study retrospectively analyzed data from 10 EGFR ex20ins-mutated NSCLC patients with LM admitted at our institution from May 2011 to June 2023. Circulating tumor DNA (ctDNA) from cerebrospinal fluid (CSF) and matched plasma samples was analyzed using next-generation sequencing. All patients received high-dose furmonertinib combined with intraventricular chemotherapy (IVC) as salvage therapy. Data on patient demographics, treatment efficacy, and safety outcomes were collected. RESULTS: The most common insertion mutation identified in this study was p.A767_V769dup (n = 4, 40%), followed by D770-N771insY (n = 2, 20%). Nine patients had EGFR ex20ins occurring in the EGFR loop region following the C-helix, whereas only one patient had an EGFR ex20ins (A763_Y764insFQEA) occurring in the C-helix of the tyrosine kinase domain. LM response assessment using the RANO-LM criteria revealed that 6 patients (60%, 95% CI 26.2-87.8%) achieved a response, 3 had stable disease, and 1 had progressive disease. The median progression-free survival and overall survival were estimated to be 6.5 months and 8.8 months, respectively. The most commonly reported treatment-related adverse events were rash (n = 7) and diarrhea (n = 7), with no treatment-related deaths occurring. CONCLUSIONS: The current study demonstrated that high-dose furmonertinib plus IVC as salvage treatment for patients with LM harboring EGFR ex20ins mutations had promising clinical benefits and a manageable safety profile.

The Combined Effects of Circular RNA Methylation Promote Pulmonary Fibrosis.

m6A (N6-methyladenosine) is the most common type of RNA methylation modification, mainly occurring on mRNA. Whether m6A-modified circular RNAs (circRNAs) are involved in pulmonary fibrosis in different settings remains unclear. Using an m6A-circRNA epitranscriptomic chip, candidate circRNAs were selected, among which hsa_circ_0000672 and hsa_circ_0005654 were specifically involved in SiO2-induced pulmonary fibrosis by targeting the same protein, eIF4A3, indicating that the m6A modification of these two circRNAs has a synergistic effect on fibroblast dysfunction induced by SiO2. A mechanistic study revealed that the m6A modification of circRNAs was mainly mediated by the methyltransferase METTL3. Furthermore, METTL3 promoted the activation, migration, and activity of pulmonary fibroblasts and participated in SiO2-induced pulmonary fibrosis via the circRNA m6A modification. m6A methylation of circRNAs mediates silica-induced fibrosis, enriching the understanding of circRNAs and uncovering a potential new target for treating fibrosis-related diseases.

A novel intergenic region ALK fusion is targetable by alectinib in a non-small cell lung cancer patient with brain metastasis.

Anaplastic lymphoma kinase ( ALK ) rearrangement defines a unique nonsmall cell lung cancer (NSCLC) molecular subtype, of which the patients could potentially benefit from anti- ALK therapies. So far, the outcomes of the canonical echinoderm microtubule-associated protein-like ( EML-ALK ) patients subjected to ALK inhibitors are well established. However, given the increasing complexity of ALK fusion partners, as detected by high-throughput sequencing, the responses of those with rare ALK fusion events remain to be explored. Here, we report a lung adenocarcinoma patient with brain metastasis harboring an ARHGAP5 downstream intergenic region ALK fusion, as detected by using DNA-based next-generation sequencing, who experienced a partial response to alectinib treatment. While whole- transcriptome RNA sequencing (RNA-seq) failed to identify potential ALK fusion transcripts, subsequent targeted deep RNA-seq revealed the expression of EML4-ALK transcripts in the tumor tissue. Given the increasing application of the ALK-tyrosine kinase inhibitors (TKIs), it is extremely crucial to define the patients who could be suitable for this treatment in clinic. The present case has provided supporting evidence that noncanonical ALK rearrangements on the genomic level are often functionally relevant and targetable by ALK-TKI, particularly in cases with sub-optimal quantity and quality for RNA validation.

Clinical research on therapeutic effect of combined application of lobaplatin and irinotecan in treating recurrant small cell lung cancer.

To observe and analyze the therapeutic effect of combinated application of lobaplatin and irinotecan in treating recurrant small cell lung cancer. The 140 patients who were treated in our hospital for recurrant small cell lung cancer were selected as research objects. All selected patients were subjected to combined application of obaplatin and irinotecan, the total therapeutic effect was observed, and the adverse reactions occurring during treatment were recorded. Through observing the total treatment effective ratio of 140 patients recurrant small cell lung cancer, the number of complete remission cases, number of partial remission cases, number of stable disease cases, and number of disease progression cases were 40(28.57%), 28(20.00%), 30(21.43%), 42(30.00%), respectively, with total effective ratio of 48.57%. The average time to progression (TTP) was (4.5±0.8) months, average overall survival (OS) was (7.6±1.2) months. The toxic and adverse effects mainly included hematological toxicity and gastrointestinal adverse reaction, such as leukocyte reduction, neutrophil reduction, thrombocytopenia, decreased hemoglobin, nausea and vomiting, diarrhea. No toxicity-related death occurred. In treatment of patients with recurrant small cell lung cancer, the combined application of lobaplatin and irinotecan can achieve great results, which is a safe and reliable way of treatment.

MCPIP1 mediates silica-induced cell migration in human pulmonary fibroblasts.

Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO2). Phagocytosis of SiO2 in the lungs initiates an inflammatory cascade that results in fibroblast proliferation and migration followed by fibrosis. According to previous data from our laboratory, monocyte chemotactic protein-1 (MCP-1) plays a critical role in fibroblast proliferation and migration in conventional two-dimensional (2D) monolayer cultures. The present study aimed to explore the downstream cascade of MCP-1 in both 2D and three-dimensional (3D) cell culture models of silicosis. Experiments using primary cultured adult human pulmonary fibroblasts (HPF-a) demonstrated the following: 1) SiO2 treatment induces expression of MCP-1-induced protein (MCPIP1) in a time- and dose-dependent manner in both 2D and 3D cultures; 2) the MAPK and phosphatidylinositol-3-kinase (PI3K)/Akt pathways are involved in SiO2-induced MCPIP1 expression; and 3) MCPIP1 induction mediates the SiO2-induced increase in cell migration in both 2D and 3D cultures. The effect of MCP-1 in silicosis occurs mainly through MCPIP1, which, in turn, mediates the observed SiO2-induced increase in pulmonary fibroblast migration. However, the time frame for MCPIP1 induction differed between 2D and 3D cultures, indicating that, compared with conventional 2D cell culture systems, 3D culture may be useful for analyses of fibroblast physiology under conditions that more closely resemble in vivo environments. Our study determined the link between fibroblast-derived MCPIP1 and SiO2-induced cell migration, and this finding provides novel evidence of the potential of MCPIP1 in the development of novel therapeutic strategies for silicosis.

Efficacy of Whole-Lung Lavage in Treatment of Pulmonary Alveolar Proteinosis.

The aim of the study was to investigate the therapeutic effect of whole-lung lavage (WLL) for pulmonary alveolar proteinosis (PAP). The cohort studies that investigated the therapeutic effect of WLL for PAP were selected strictly on the basis of the inclusion and exclusion criteria. The statistical analysis was performed using STATA statistical software (version 12.0; Stata Corporation, College Station, TX). Twelve studies were included in this meta-analysis. Totally, 206 PAP patients who received WLL were recruited in the 12 studies. We compared the differences in blood gas analysis and lung function before and after the treatment in this meta-analysis. The results indicated that there were statistical differences in the levels of diffusing capacity for carbon monoxide, forced expiratory volume in 1 second, forced vital capacity, and arterial partial pressure of oxygen after the treatment of WLL for patients with PAP, whereas there were no evident differences in the levels of arterial partial pressure of carbon dioxide and arterial oxygen saturation. In conclusion, WLL can evidently improve the diffusing capacity for carbon monoxide, forced expiratory volume in 1 second, forced vital capacity, and arterial partial pressure of oxygen of patients with PAP, thus WLL may be an important treatment of PAP.

Macrophage-derived MCPIP1 mediates silica-induced pulmonary fibrosis via autophagy.

BACKGROUND: Silicosis is characterized by accumulation of fibroblasts and excessive deposition of extracellular matrix. Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) plays a critical role in fibrosis induced by SiO2. However, the details of the downstream events of MCPIP1 activity in pulmonary fibrosis remain unclear. To elucidate the role of MCPIP1-induced autophagy in SiO2-induced fibrosis, both the upstream molecular mechanisms and the functional effects of SiO2 on cell apoptosis, proliferation and migration were investigated. RESULTS: Experiments using primary cultures of alveolar macrophages from healthy donors and silicosis patients as well as differentiated U937 macrophages demonstrated the following results: 1) SiO2 induced macrophage autophagy in association with enhanced expression of MCPIP1; 2) autophagy promoted apoptosis and activation of macrophages exposed to SiO2, and these events induced the development of silicosis; 3) MCPIP1 facilitated macrophage apoptosis and activation via p53 signaling-mediated autophagy; and 4) SiO2-activated macrophages promoted the proliferation and migration of fibroblasts via the MCPIP1/p53-mediated autophagy pathway. CONCLUSIONS: Our results elucidated a link between SiO2-induced fibrosis and MCPIP1/p53 signaling-mediated autophagy. These findings provide novel insight into the potential targeting of MCPIP1 or autophagy in the development of potential therapeutic strategies for silicosis.

Role of human pulmonary fibroblast-derived MCP-1 in cell activation and migration in experimental silicosis.

BACKGROUND: Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO2). Phagocytosis of SiO2 in the lung initiates an inflammatory cascade that results in fibroblast proliferation and migration and subsequent fibrosis. Clinical evidence indicates that the activation of alveolar macrophages by SiO2 produces rapid and sustained inflammation that is characterized by the generation of monocyte chemotactic protein 1 (MCP-1), which induces fibrosis. Pulmonary fibroblast-derived MCP-1 may play a critical role in fibroblast proliferation and migration. METHODS AND RESULTS: Experiments using primary cultured adult human pulmonary fibroblasts (HPF-a) demonstrated the following results: 1) SiO2 treatment resulted in the rapid and sustained induction of MCP-1 as well as the elevation of the CC chemokine receptor type 2 (CCR2) protein levels; 2) pretreatment of HPF-a with RS-102895, a specific CCR2 inhibitor, abolished the SiO2-induced increase in cell activation and migration in both 2D and 3D culture systems; and 3) RNA interference targeting CCR2 prevented the SiO2-induced increase in cell migration. CONCLUSION: These data demonstrated that the up-regulation of pulmonary fibroblast-derived MCP-1 is involved in pulmonary fibroblast migration induced by SiO2. CCR2 was also up-regulated in response to SiO2, and this up-regulation facilitated the effect of MCP-1 on fibroblasts. Our study deciphered the link between fibroblast-derived MCP-1 and SiO2-induced cell migration. This finding provides novel insight into the potential of MCP-1 in the development of novel therapeutic strategies for silicosis.

Elevated tumor markers in patients with pulmonary alveolar proteinosis.

BACKGROUND: The role of tumor markers in pulmonary alveolar proteinosis (PAP) remains unclear. This study investigated the tumor markers in serum and bronchoalveolar lavage fluid (BALF) in PAP patients and explored the relationship between tumor markers and the severity of PAP. METHODS: We retrospectively reviewed 38 patients with PAP. RESULTS: Mean serum carcinoembryonic antigen (CEA) and CYFRA21-1 levels were higher than the cut-off values (12.7 ± 17.5 ng/mL and 10 ± 10.66 ng/mL, respectively). Significant correlations were found between levels of CEA and neuron-specific enolase (NSE) in serum and serum lactate dehydrogenase (LDH) values (r=0.60, p<0.001 and r=0.56, p<0.001, respectively). A significant correlation was also observed between levels of squamous cell carcinoma (SCC) in serum and PaO2 and PA-aO2 (r=-0.49 p=0.01 and r=-0.51, p=0.01, respectively). The changes of CEA, SCC and NSE levels were consistent with the changes of LDH and PaO2. The serum levels of CEA, NSE and SCC were significantly lower after whole lung lavage compared with those before (8.7 ± 10.6 vs. 15.7 ± 22, 7.9 ± 5.2 vs. 16.6 ± 11.8, 0.4 ± 0.24 vs. 0.59 ± 0.42; p<0.05, respectively). CONCLUSIONS: Elevated serum tumor marker levels were found in PAP patients. The serum levels of CEA, NSE and SCC may reflect the severity of the disease and predict the therapeutic effect of whole lung lavage.

[The long-term therapeutic effects of silicosis by repeat the whole lung lavage].

OBJECTIVE: To preliminary study the long term therapeutic effects of repeat the whole lung lavage (RWLL) in the treatment of silicosis. METHODS: A total of 60 patients with silicosis in the same stone mine were randomly and equally divided into repeat the whole lung Lavage (RWLL) group and whole lung Lavage (WLL) group based on silicosis staging, age and working age of dust exposure. Comparative analysis was performed to evaluate the long-term therapeutic efficacy and safety of RWLL. The cell count and SiO2 content were measured in twice right lung bronchoalveolar lavage fluid(BALF) of the RWLL group. RESULTS: Four years after treatment, the cough and asthma improvement rates of the RWLL group were 68.4% and 75.0% higher than those (52.4%and 57.9%) of the WLL group (P > 0.05). Six years after treatment, the asthma improvement rate (70.0%) of the RWLL group was significantly higher than that (36.8%) of the WLL group (P < 0.05). The RWLL group showed slight decrease in forced vital capacity (FVC) and forced expiratory volume in one second (FEV1.0) after treatment (P > 0.05), while the WLL group showed significant decrease in FVC and FEV1.0 in the six years after treatment (P<0.05). Four and Six years after treatment, the RWLL group had higher no change rate and lower progression rate and significant progression rate than the WLL group in terms of chest X-ray (P>0.05). In the RWLL group,the first time the right lung BALF test showed a number of cells 6.71×10(7)∼2.14×10(9)/L, average 4.50×10(8)/L, pulmonary alveoli macrophages (PAM) ratio of 0.873∼0.980, average 0.954 and SiO2 content of 18∼104.7 mg, average 93.7 mg; the second test showed a number of cells 5.71×10(6)∼1.30×10(9)/L, average 9.12×10(7)/L; PAM ratio 0.710∼0.926, average 0.870 and SiO2 content of 6∼90.2 mg, average 46.2 mg. The RWLL group happened hemoptysis, chest pain one case in perioperative period, the incidence of 6.7%. The RWLL group complicated by left pneumothorax, pulmonary infection one case and the WLL group complicated by one case of lung cancer in a year of follow-up. CONCLUSION: RWLL is reasonable and safe treatment which could help to further improve the long-term effects of WLL for silicosis.

Case report: Almonertinib in combination with bevacizumab for leptomeningeal metastases from epidermal growth factor receptor-mutation non-small cell lung cancer: Case series.

Leptomeningeal metastasis (LM) is a lethal complication of advanced non-small cell lung cancer (NSCLC) with rapid deterioration and poor prognosis. It has no standard treatment for epidermal growth factor receptor mutation (EGFRm) NSCLC, and improving the clinical outcomes for patients with LM has become an urgent problem in clinical treatment. Both almonertinib and bevacizumab are capable of crossing the blood-brain barrier with comparable central nervous system effectiveness. To date, the almonertinib treatment in combination with bevacizumab in EGFRm NSCLC with LM has not been studied. We herein present five cases to further evaluate the effectiveness and tolerability of almonertinib in combination with bevacizumab for patients with EGFRm NSCLC and LM. For the first time, we report that almonertinib plus bevacizumab can not only effectively improve the neurological symptoms caused by LM but also prolong the survival time of patients with limited and controllable side effects, which provided a novel therapeutic approach for LM from EGFRm NSCLC.

Case report: Rechallenge with EGFR-TKIs after immunotherapy in EGFR-mutated non-small cell lung cancer with leptomeningeal metastasis.

Rechallenge of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) after PD-1 blockade failure was an effective therapy for non-small cell lung cancer (NSCLC) patients with resistance to EGFR-TKIs. The third-generation TKIs, like osimertinib and furmonertinib, can reach higher concentration in the cerebrospinal fluid (CSF) than other TKIs, and exhibit a beneficial effect in NSCLC patients with leptomeningeal metastases (LM) harboring sensitive EGFR mutation. Here, we report that two-stage IV pulmonary adenocarcinoma patients with LM harboring an EGFR L858R mutation benefit from the third-generation EGFR-TKIs rechallenge after immune checkpoint inhibitor (ICI) and anti-angiogenic agent combination therapy. Complete response (CR) to partial response (PR) of central nervous system (CNS) response was achieved immediately after the administration of furmonertinib and osimertinib. We conducted next-generation sequencing (NGS) and IHC to elucidate the evolution of driver mutations and the immune microenvironment. In conclusion, these two cases might provide a therapeutic strategy for further clinical practice. More research was needed to elucidate the resistance mechanisms and improve current treatment strategies in EGFR-mutated patients with LM.

Erratum: circRNA Mediates Silica-Induced Macrophage Activation Via HECTD1/ZC3H12A-Dependent Ubiquitination: Erratum.

[This corrects the article DOI: 10.7150/thno.21648.].

Sequence-dependent synergistic effect of aumolertinib-pemetrexed combined therapy on EGFR-mutant non-small-cell lung carcinoma with pre-clinical and clinical evidence.

BACKGROUND: Inevitably developed resistance of the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) limited its clinical benefit on non-small cell lung cancer (NSCLC). Upfront combination therapy is promising to prevent this resistance. Compelling clinical evidence indicated the failure of third-generation EGFR TKIs combined with either immunotherapy or antiangiogenic agents. In comparison, combined treatment of third-generation EGFR TKIs and chemotherapy might be a favorable choice. Herein, we systematically analyzed and compared the effects of pemetrexed and a novel third-generation EGFR TKI aumolertinib combined in different sequences, subsequently revealed the potential mechanisms and proved the optimal combination schedule with clinical retrospective study. METHODS: Three combination schedules involving pemetrexed and aumolertinib in different sequences were developed. Their inhibition effects on cell proliferation and metastasis were firstly compared upon three human NSCLC cell lines in vitro, by cell counting kit-8, colony formation, wound healing and transwell assays respectively. Further evaluation in vivo was proceeded upon H1975 and HCC827 xenograft model. Gene and protein expression were detected by Q-PCR and western blot. Drug concentration was determined by LC-MS/MS. VEGF secretion was determined by ELISA. Tumor vessel was visualized by immunofluorescence. Lastly, a clinical retrospective study was raised with 65 patients' data. RESULTS: The combination of pemetrexed and aumolertinib exhibited a sequence-dependent and EGFR mutant-dependent synergistic effect in vitro and in vivo. Only treatment with aumolertinib following pemetrexed (P-A) exhibited synergistic effect with stronger anti-tumor growth and anti-metastasis ability than monotherapy and also other combination sequences. This synergism could exclusively be observed in H1975 and HCC827 but not A549. Pathway analysis showed that P-A significantly enhanced the suppression of EGFR pathway. In addition, our results intriguingly found an obvious reduction of VEGF secretion and the accompanying normalization of the intratumor vessel, consequently increasing intratumoral accumulation of pemetrexed in P-A group. Finally, the clinical retrospective study verified the synergistic effect of P-A combination by significantly superior tumor response than aumolertinib monotherapy. CONCLUSION: Aumolertinib-pemetrexed combined therapy is promising for EGFR mutant NSCLC but only in right administration sequence. P-A could become an advantageous combination strategy in clinical with synergistic inhibition of tumor growth and metastasis.

Genomic profiling of non-small cell lung cancer with the rare pulmonary lymphangitic carcinomatosis and clinical outcome of the exploratory anlotinib treatment.

Background: To evaluate the potential treatment for patients with non-small cell lung cancer (NSCLC) and rare malignant pulmonary lymphangitis carcinomatosis (PLC), our study provided a genomic profile and clinical outcome of this group of patients. Methods: We retrospectively reviewed patients with NSCLC who developed PLC. The genomic alterations, tumor mutation burden (TMB), and microsatellite instability (MSI) based on DNA-based next-generation sequencing were reviewed and compared in a Chinese population with lung adenocarcinomas (Chinese-LUAD cohort). Clinical outcomes after exploratory anlotinib treatment and factors influencing survival are summarized. Results: A total of 564 patients with stage IV NSCLC were reviewed, and 39 patients with PLC were included. Genomic profiling of 17 adenocarcinoma patients with PLC (PLC-LUAD cohort) revealed TP53, EGFR, and LRP1B as the three most frequently altered genes. EGFR was less mutated in PLC-LUAD than Chinese-LUAD cohort of 778 patients (35.3% vs. 60.9%, P = 0.043). BRIP1 was mutated more often in the PLC-LUAD cohort (11.8% vs. 1.8%, P= 0.043). Two patients presented with high tumor mutational burden (TMB-H, 10 mutations/MB). Combing alterations in the patient with squamous cell carcinoma, the most altered pathways of PLC included cell cycle/DNA damage, chromatin modification, the RTK/Ras/MAPK pathway and VEGF signaling changes. Fourteen of the participants received anlotinib treatment. The ORR and DCR were 57.1% and 92.9%, respectively. Patients achieved a median progression-free survival of 4.9 months and a median overall survival of 7 months. The adverse effects were manageable. In patients with adenocarcinoma, the mPFS (5.3 months vs. 2.6 months) and mOS (9.9 months vs. 4.5 months) were prolonged in patients receiving anlotinib treatment compared to those receiving other treatment strategies (P < 0.05). Conclusion: Patients with PLC in NSCLC demonstrated distinct genetic alterations. The results improve our understanding of the plausible genetic underpinnings of tumorigenesis in PLC and potential treatment strategies. Exploratory anlotinib treatment achieved considerable benefits and demonstrated manageable safety.

A missing piece of the puzzle in pulmonary fibrosis: anoikis resistance promotes fibroblast activation.

BACKGROUND: Pulmonary fibrosis initiates a pneumonic cascade that leads to fibroblast dysfunction characterized by excess proliferation. Anoikis is a physiological process that ensures tissue development and homeostasis. Researchers have not clearly determined whether disruption of anoikis is involved in pulmonary fibrosis. RESULTS: Here, we investigated the mechanism by which silica induces fibroblast activation via anoikis resistance and subsequent fibrosis. Anoikis of lung fibroblasts, alveolar epithelial cells and endothelial cells during the process of fibrosis was detected using CCK-8, western blot, cell count and flow cytometry (FCM) assays. Although the three cell types showed similar increases in proliferation, the expression of NTRK2, a marker of anoikis resistance, was upregulated specifically in fibroblasts, indicating the unique proliferation mechanism of fibroblasts in pulmonary fibrosis, which may be related to anoikis resistance. Furthermore, the CRISPR/Cas9 system was used to investigate the molecular mechanism of anoikis resistance; the SiO2-induced inflammatory response activated the MAPK/PI3K signaling pathway in lung fibroblasts and then induced the expression of the ZC3H4 protein, which specifically mediated anoikis resistance, followed by pulmonary fibrosis. CONCLUSIONS: The current study revealed a specific pattern of fibroblast proliferation, and strategies targeting anoikis resistance may inhibit the pathological process of pulmonary fibrosis. This result provides a new approach for treating pulmonary fibrosis and new insights into the potential application of ZC3H4 in the development of novel therapeutic strategies for mitigating pulmonary fibrosis.

Lung adenocarcinoma patients with KEAP1 mutation harboring low immune cell infiltration and low activity of immune environment.

BACKGROUND: Kelch-like ECH-associated protein 1 (KEAP1) has been identified as a cancer driver gene in lung adenocarcinoma (LUAD), and increased evidence has given us clues about the association of KEAP1 mutation and immune characteristics. We assessed the association between KEAP1 mutation and tumor microenvironment in LUAD systematically. METHODS: With the data collected from The Cancer Genome Atlas (TCGA), we evaluated the association of KEAP1 mutation with tumor infiltrating leukocytes (TILs), including dendritic cell, CD8 T cell, CD4 T cell, neutrophil, B cells, and macrophage. Expression differences of the markers of those immune cells were also measured. We further compared the expression of antigen presentation genes and chemokines and the enrichment score of immune-related pathways. RESULTS: KEAP1 mutation had significant association with lower TILs and cytotoxic T lymphocyte. Strikingly, almost all of antigen presentation genes and chemokine showed lower expression in KEAP1-mutated tumors. Moreover, most of immune-related pathways were less active in KEAP1-mutated tumors. As expected, KEAP1-wild type LUADs favored better overall survival after immunotherapy. Finally, one patient harboring KEAP1 mutation along with a lack of immune cells infiltration in tumor microenvironment failed to respond to checkpoint inhibitor despite high tumor mutational burden (TMB). CONCLUSIONS: KEAP1 mutation has a significant effect on the tumor immune milieu of LUAD and may play as a predictive biomarker of immunotherapy for LUAD patients.

LINC01001 Promotes Progression of Crizotinib-Resistant NSCLC by Modulating IGF2BP2/MYC Axis.

Background: Crizotinib is a microtubule-related protein-4-anaplastic lymphoma kinase (EML4-ALK) multi-target tyrosine kinase inhibitor applied in the treatment of ALK-rearranged NSCLC. However, the specific molecular mechanism underlying its therapeutic effect remains unclear. Therefore, the purpose of this research is to explore the mechanism by which crizotinib targets NSCLC with ALK-rearrangement, mainly whether it is related to LINC01001 in regulating NSCLC progression via IGF2BP2/MYC axis. Methods: RT-qPCR is conducted to evaluate the mRNA levels of LINC01001, IGF2BP2 and MYC in A549/R and H1299/R cells. CCK-8 and EdU assays are performed to assess the viability and proliferation of A549/R and H1299/R cells. Western blot is conducted to measure the levels of PCNA and Ki-67 proteins in A549/R and H1299/R cells. FACs and TUNEL are performed to detect apoptosis of A549/R and H1299/R cells. Immunohistochemical staining is performed to assess the levels of Ki67 in crizotinib-resistant NSCLC tissue. Bioinformatics analysis of multiple CLIP (crosslinking-immunoprecipitation) data found potential binding sites between LINC01001 and IGF2BP2, IGF2BP2 and MYC, that are confirmed by RIP assay and RNA pulldown assay. Results: Our findings illustrated that LINC01001 is highly expressed in crizotinib-resistant NSCLC cells and associated with poor overall survival of NSCLC patients. Inhibition of LINC01001 depresses crizotinib resistance of NSCLC cells. LINC01001 interacts with IGF2BP2, and inhibition of IGF2BP2 depresses crizotinib resistance of NSCLC cells. IGF2BP2 interacts with the mRNA of MYC, and LINC01001 overexpression increases crizotinib resistance of NSCLC via MYC. Conclusion: LINC01001 promotes the progression of crizotinib-resistant NSCLC by modulating the IGF2BP2/MYC axis. Our research clarifies the specific mechanism of crizotinib-resistance in NSCLC treatment.