Pemetrexed induces ROS generation and cellular senescence by attenuating TS-mediated thymidylate metabolism to reverse gefitinib resistance in NSCLC.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) are strongly recommended for non-small-cell lung cancer (NSCLC) patients harbouring active EGFR mutations, while drug resistance makes exploring resistance mechanisms and seeking effective therapeutic strategies urgent endeavours. Thymidylate synthetase (TYMS or TS) is a dominant enzyme in thymidylate nucleotide metabolism. In this study, we found a positive correlation between TS expression and overall survival (OS) and disease-free survival (DFS) in lung adenocarcinoma. The examination of gene sets from 140 NSCLC patients received EGFR-TKI therapy demonstrated a negative correlation between high TS expression and the efficacy of EGFR-TKI therapy. 24 tissue specimens from NSCLC patients exhibited upregulated TS mRNA expression in NSCLC patients resistant to gefitinib. The NSCLC cell PC9 and HCC827 sensitive to gefitinib and relatively resistant PC9/GR and HCC827/GR cells were used to demonstrate the knockdown of TS restored the sensitivity of resistant cells to gefitinib. Furthermore, pemetrexed effectively suppressed TS-mediated thymidylate metabolism and induced ROS generation, DNA damage and cellular senescence, thereby hampering cancer progression and restoring sensitivity to gefitinib. Our findings illuminate the potential mechanism of TS-triggered gefitinib resistance and indicate inhibition of TS by pemetrexed can potentiate the effect of gefitinib in NSCLC. Pemetrexed combined with gefitinib has potent anti-progression potential in gefitinib-resistant NSCLC. This study suggests that NSCLC patients with both high TS expression and EGFR-driving mutations might benefit more from a combination strategy of EGFR-TKI and pemetrexed-based chemotherapy than EGFR-TKI monotherapy, which has profound clinical implications and therapeutic value.

Efficacy and safety of antiangiogenic agents or chemotherapy plus EGFR-TKIs in advanced non-small cell lung cancer: A systematic review and network meta-analysis.

BACKGROUND: The combination of antiangiogenic agents with epidermal growth factor receptor inhibitors (EGFR-TKIs) and chemotherapy with EGFR-TKIs are the most common combination treatment options in epidermal growth factor receptor (EGFR) positive non-small cell lung cancer (NSCLC). This network meta-analysis was performed to evaluate the differences between them. METHODS: We searched the PubMed, EMBASE and the Cochrane Controlled Trials Register up to August 2022. The primary outcomes were progression-free survival (PFS) and objective response rate (ORR). The secondary endpoints were overall survival (OS), disease control rate (DCR) and adverse events (AEs). The data of hazard ratio (HR) or risk ratio (RR) with their corresponding 95% confidence intervals (CIs) were extracted in the studies. A network meta-analysis (NMA) was used to indirectly compare the efficacy and safety of antiangiogenic agents plus EGFR-TKIs and chemotherapy plus EGFR-TKIs. RESULTS: Pooled data of included studies were demonstrated that chemotherapy plus EGFR-TKIs had a benefit in ORR compared to antiangiogenic agents plus EGFR-TKIs in patients with EGFR mutated NSCLC (RR = 1.1, 95% CI: 1.0-1.2). However, there were no significant differences in PFS, OS and DCR between in the two group (PFS: HR = 1.0, 95% CI: 0.74-1.6; OS: HR = 0.78, 95% CI: 0.45-1.5; DCR: RR = 1.0, 95% CI: 0.94-1.1). The common treatment-related AEs in the two groups were relatively manageable. CONCLUSION: Based on the efficacy and safety, the combination of chemotherapy with EGFR-TKIs is considered the best combination treatment options in advanced NSCLC with EGFR mutation.

Rechallenge of immune checkpoint inhibitors in a case with adverse events inducing myasthenia gravis.

The mechanism(s) of immune checkpoint inhibitor (ICI)-induced myasthenia gravis (MG), an immune-related adverse event (irAE) that is fatal and limits subsequent ICI use, remain unexplored. Here, through comparative genomic analysis, we identified a pathogenic p.S467C germline variant in SLC22A5 in a thymoma case with ICI-induced MG, which was found to be associated with fatty acid oxidation through its regulation on L-carnitine levels. Remarkably, ICI rechallenge with L-carnitine pretreatment led to durable response without MG-related symptoms. Thus, we provide the first clinical evidence of genetic test-directed irAE management, which integrates individualized ICI treatment into the evolving paradigm of cancer management.

Ferroptosis in cancer therapy: a novel approach to reversing drug resistance.

Ferroptosis is an intracellular iron-dependent form of cell death that is distinct from apoptosis, necrosis, and autophagy. Extensive studies suggest that ferroptosis plays a pivotal role in tumor suppression, thus providing new opportunities for cancer therapy. The development of resistance to cancer therapy remains a major challenge. A number of preclinical and clinical studies have focused on overcoming drug resistance. Intriguingly, ferroptosis has been correlated with cancer therapy resistance, and inducing ferroptosis has been demonstrated to reverse drug resistance. Herein, we provide a detailed description of the mechanisms of ferroptosis and the therapeutic role of regulating ferroptosis in reversing the resistance of cancer to common therapies, such as chemotherapy, targeted therapy and immunotherapy. We discuss the prospect and challenge of regulating ferroptosis as a therapeutic strategy for reversing cancer therapy resistance and expect that our review could provide some references for further studies.

The miRNA125a-5p and miRNA125b-1-5p cluster induces cell invasion by down-regulating DDB2-reduced epithelial-to-mesenchymal transition (EMT) in colorectal cancer.

Background: MicroRNA (miRNA) is a kind of non-coding RNA that regulates gene expression and is involved in tumor development. MiRNA-125 is reportedly aberrantly expressed in colorectal cancer tissue; however, its potential function and underlying mechanism remain unclear. The present study aimed to investigate the expression level and potential role of the miRNA-125 family in the invasion and migration of colorectal cancer. Methods: To further understand the role of the miRNA-125 family in metastatic colorectal cancer, we overexpressed miRNA-125 in the SW480 cell line by transfection with the miRNA-125 family mimics or a sponge. Methyl thiazolyl tetrazolium (MTT) assay was performed to identify the effect of the miRNA-125 family on cell proliferation, and a Transwell filter assay was used to detect the role of the miRNA-125 family in migration and invasion. A luciferase assay was carried out to confirm the binding site of miRNA-125 and the target gene, damage specific DNA binding protein 2 (DDB2). Western blot was applied to detect the expression levels of DDB2 and the markers of epithelial-to-mesenchymal transition (EMT) in colorectal cancer cells. Results: The real-time polymerase chain reaction (PCR) results showed that miR-125a-5p and miR-125b-1-5p were up-regulated in metastatic colorectal cancer tissues. The Transwell filter assay results appeared that miR-125a-5p and miR-125b-1-5p could promote the invasion and migration of colorectal cancer cells. The luciferase assay data confirmed the binding site of miR-125a-5p and miR-125b-1-5p on the 3' untranslated region (3'UTR) of DDB2 messenger RNA (mRNA). The real-time PCR and Western blot results indicated that miR-125a-5p and miR-125b-1-5p could regulate the expression levels of DDB2 and EMT markers, and lower DDB2 expression was observed in metastatic tissues. Conclusions: Our findings illustrated that miRNA125a-5p and miRNA125b-1-5p could reduce the expression of DDB2 by binding to the 3'UTR region, and then regulate the expression levels of EMT markers, leading to the enhanced invasion and metastasis of colorectal cancer cells. Thus, miRNA125a-5p and miRNA125b-1-5p might be novel markers of colorectal cancer migration and potential therapeutic targets to treat metastatic colorectal cancer patients.

Concurrent use of anlotinib overcomes acquired resistance to EGFR-TKI in patients with advanced EGFR-mutant non-small cell lung cancer.

BACKGROUND: Acquired resistance development is a major challenge in the epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment of non-small cell lung cancer (NSCLC). Here, we investigated the potential effects of the concurrent use of anlotinib and EGFR-TKI to overcome acquired resistance. METHODS: We conducted a preclinical study to evaluate the antitumor effects of gefitinib + anlotinib in gefitinib-resistant lung adenocarcinoma models in vitro and in vivo. We then investigated the treatment effect of EGFR-TKI + anlotinib therapy in 24 advanced EGFR-mutant NSCLC patients after EGFR-TKI acquired resistance between January 2018 and August 2020. RESULTS: Anlotinib reversed gefitinib resistance in gefitinib-resistant lung adenocarcinoma models by enhancing the antiproliferative and proapoptotic effects of gefitinib. The gefitinib + anlotinib treatment exerted a synergistic antitumor effect by downregulating the activation of VEGFR2 and downstream effectors, Akt and ERK. The EGFR-TKI + anlotinib therapy exhibited an objective response rate of 20.8% and a disease control rate of 95.8%. Median progression-free survival (PFS) was 11.53 ± 2.41 months, but median overall survival was not reached. The median PFS was longer in patients experiencing gradual progression (13.30 ± 1.69 months) than in patients with dramatic progression (6.80 ± 1.75 months, p = 0.017). One grade 3 adverse event was noted (diarrhea, n = 2, 8.3%), and grade 4 or 5 adverse events were absent. CONCLUSIONS: EGFR-TKI combined with anlotinib demonstrated powerful antitumor activity in vitro and in vivo. Concurrent use of anlotinib overcomes acquired resistance to EGFR-TKI in advanced EGFR-mutant NSCLC patients.

Efficacy and acquired resistance of EGFR-TKI combined with chemotherapy as first-line treatment for Chinese patients with advanced non-small cell lung cancer in a real-world setting.

BACKGROUND: To compare the benefits and explore the cause of acquired resistance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and its combination with chemotherapy in advanced non-small-cell lung cancer (NSCLC) patients harboring EGFR mutation in a real-life setting. METHODS: This retrospective analysis included 117 advanced NSCLC patients with EGFR mutation who underwent next-generation sequencing (NGS) prior to treatment. The combination group included 50 patients who received the regimen of EGFR-TKI combined with chemotherapy, while the EGFR-TKI monotherapy group included 67 patients treated with TKI only. The primary endpoint of this study was progression-free survival (PFS); the secondary endpoints were overall survival (OS), response rate, and toxicity. RESULTS: The median PFS was significantly longer in the combination group than in the EGFR-TKI monotherapy group (19.00 months [95% CI, 14.67-23.33] vs. 11.70 months [95% CI, 10.81-12.59], p < 0.001). Subgroup analysis showed a similar trend of results. The median OS was not reached in the combination group and was 38.50 (95% CI, 35.30-41.70) months in the EGFR-TKI monotherapy group (p = 0.586). Patients in the combination group were more likely to experience adverse events, most of which showed the severity of grade 1 or 2. T790M mutation remains the main reason for acquired resistance, and the frequency of T790M mutation was similar between the two groups (p = 0.898). CONCLUSIONS: Compared with EGFR-TKI monotherapy, EGFR-TKI combined with chemotherapy significantly improved PFS in advanced NSCLC patients with EGFR mutation, with acceptable toxicity.

The development and validation of a nomogram for predicting brain metastases in lung squamous cell carcinoma patients: an analysis of the Surveillance, Epidemiology, and End Results (SEER) database.

BACKGROUND: The incidence of brain metastasis (BM) in patients suffering from lung squamous cell carcinoma (LUSC) is lower than that in patients suffering from non-squamous cell carcinoma (NSCC) and there are few studies on BM of LUSC. The purpose of this investigation was to ascertain the risk factors of LUSC, as well as to establish a nomogram prognostic model to predict the incidence of BM in patients with LUSC. METHODS: Patients diagnosed with LUSC between 2010 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database and the patient data were collated. All patients diagnosed from 2010-2012 were allocated into the training cohort, and the remaining patients diagnosed from 2013-2015 formed the test cohort. Using factors that were screened out through logistic regression analyses, the nomogram in the training cohort was established. It was then evaluated for discrimination and calibration using the test cohort. The performance of the nomogram was assessed by quantifying the area under the receiver operating characteristic (ROC) curve and evaluating the calibration curve. RESULTS: A total of 26,154 LUSC patients were included in the study. The training cohort consisted of 16,543 patients and there were 8611 patients in the test cohort. Age, marital status, insurance status, histological grade, tumor location, laterality, stage of the cancer, number of metastatic organs, chemotherapy, surgery, and radiotherapy were highly correlated with the incidence of BM. The area under the ROC curve (AUC) of the nomogram for the training cohort and the test cohort were 0.810 [95% confidence interval (CI): 0.796 to 0.823] and 0.805 (95% CI: 0.784 to 0.825), respectively. The slope of the calibration curve was close to 1. CONCLUSIONS: The nomogram was able to accurately predict the incidence of BM. This may be beneficial for the early identification of high-risk LUSC patients and the establishment of individualized treatments.

Checkpoint inhibitor pneumonitis in Chinese lung cancer patients: clinical characteristics and risk factors.

BACKGROUND: Checkpoint inhibitor pneumonitis (CIP) may be accompanied by lung cancer in patients treated with immune checkpoint inhibitors (ICI). This study aimed to test the risk factors, genetic and clinical characteristics of CIP in a cohort of Chinese patients with lung cancer. METHODS: We retrospectively reviewed the medical records of eligible patients who received ICI treatment from December 2017 to September 2020 in our hospital. Patient characteristics, ICI protocols, and mutation frequencies of related genes are compared between the CIP group and the non-CIP group. RESULTS: A total of 94 patients were recruited. Of them, 16 (17.0%) patients developed CIP. Multivariate logistic regression analysis suggested Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥2 [odds ratio (OR) =6.53; 95% confidence interval (CI), 1.74-24.46; P=0.005] and previous pulmonary fibrosis (OR =20.13; 95% CI, 3.64-111.44; P=0.001) were independently associated with a higher incidence of CIP. There was an increasing trend, although not statistically significant, in the risk of CIP in patients with TP53 mutation (P=0.280). Most CIP patients were managed successfully following the current guideline. However, serious events (including one death) were still observed. CONCLUSIONS: ECOG PS ≥2 and earlier pulmonary fibrosis were closely correlated to the occurrence of CIP in Chinese lung cancer patients after ICI treatment. Early screening and prompt intervention are necessary for the management of CIP.

A multicenter real-world study of tumor-derived DNA from pleural effusion supernatant in genomic profiling of advanced lung cancer.

BACKGROUND: Pleural effusion (PE) is commonly observed in advanced lung cancer. Research has suggested that molecular profiling of PE could be used to detect tumor driver mutations, thus informing clinical decision-making. However, the performance of PE samples in a real-world setting has yet to be examined. METHODS: A total of 678 metastatic lung cancer patients with pleural effusion were enrolled in this study. Cohort 1 included 22 patients whose PE and matched plasma samples were simultaneously collected as a pilot study. Cohort 2 comprised 656 patients, from whom 734 samples were collected in a real world setting. These samples were subjected to targeted next-generation sequencing (NGS) of 1,021 cancer-related genes. RESULTS: PE supernatant was the preferred choice for genetic profiling. While the maximal somatic allele frequency (MSAF) of plasma in patients with M1a stage was significantly lower than that in patients with M1b/c stages (4.4%±9.6% vs. 9.0%±14.1%, P<0.01), the MSAF of PE supernatant was similar between M1a and M1b/c stages. PE supernatant demonstrated higher sensitivity than plasma in detecting actionable mutations in cohort 1 (81.8% vs. 45.5%, P=0.01) as well as in M1a disease (84.7% vs. 42.1%, P<0.01), but not in M1b/c disease, in cohort 2. Known resistant mutations were identified in 72 of the 117 patients who were resistant to first- or second-generation EGFR-TKIs, 22 of the 42 patients who were resistant to osimertinib, and 9 of the 13 patients who were resistant to crizotinib. Remarkably, PE supernatant outperformed plasma in identifying mutations that confer resistance to first- and second-generation EGFR-TKIs (75.4% vs. 29.8%, P<0.001). CONCLUSIONS: This real-world large cohort study verified that PE supernatant had higher sensitivity than plasma for identifying actionable mutations, including resistance mutations. PE supernatant would be preferred by physicians for assessing tumor genomics in advanced lung cancer when tumor tissue is not available.

CARM1 promotes non-small cell lung cancer progression through upregulating CCNE2 expression.

The underlying molecular mechanisms of tumorigenesis and progression of non-small cell lung cancer (NSCLC) are not yet fully elucidated. In the present study, invitro functional dissections suggest that siRNA-mediated silencing of CCNE2 profoundly attenuated the proliferative and colony-formative abilities of NSCLC PC9 and HCC827 cells, while forced overexpression of CCNE2 significantly strengthened the proliferative and colony-formative capabilities of these cells. Intriguingly, by ChIP and luciferase reporter gene assays, we observed that CARM1 is recruited to the promoter regions of CCNE2 gene and acts as a transcriptional activator. Mechanically, the asymmetric di-methylation of H3R17me2a and H3R26me2a, as the catalytic substrates of CARM1, were highly enriched at the core promoter regions of CCNE2 gene, thereby activating the expression of CCNE2. In vitro and in vivo rescue experiments demonstrated that restoration of CCNE2 expression significantly abolished the CARM1 shRNA-mediated inhibition of cell proliferation, indicating that the oncogenic function of CARM1, at least partially, depended on the activation of CCNE2. Inhibition of CARM1 enzymatic activity could significantly repress CCNE2 expression in NSCLC cells. In addition, the expression of CARM1 was significantly elevated and positively correlated with CCNE2 levels in 20 cases of NSCLC patients. Both CARM1 and CCNE2 are highly associated with shorter 10-year overall survival of at a large cohort of 461 cases of NSCLC patients from the Kaplan-Meier plotter database. To summarize, these findings provide compelling evidence that CARM1 could promote NSCLC progression via activation of CCNE2, paving the way for future therapeutic strategies in NSCLC.

LncRNA FTX activates FOXA2 expression to inhibit non-small-cell lung cancer proliferation and metastasis.

Lung cancer leads to the highest mortality among all cancer types in the world, and non-small-cell lung cancer (NSCLC) occupies over 80% of the lung cancer cases. Numerous studies have demonstrated that long non-coding RNA (lncRNA) is involved in various human diseases including cancer. LncRNA FTX was firstly identified in Xist gene locus and was dysregulated in many human cancers. However, the function of FTX in NSCLC is still unclear. Here, we report that long non-coding RNA FTX expression level is down-regulated in NSCLC clinical tissue samples and cell lines. Ectopic expression of FTX inhibits proliferation and metastasis of lung cancer cells in vitro and in vivo. Furthermore, we find that FTX overexpression activates the expression of transcription factor FOXA2, an important regulator in lung cancer progression, and we reveal a novel FTX/miR-200a-3p/FOXA2 competing endogenous RNA regulatory axis in lung cancer cells. Our results provide new insights and directions for exploring the function of FTX in lung cancer progression.

PUMA-mediated epithelial cell apoptosis promotes Helicobacter pylori infection-mediated gastritis.

The molecular mechanism responsible for Helicobacter pylori infection-mediated gastritis and carcinogenesis is not yet clear. Increased evidence suggests that chronic gastritis and elevated gastric epithelial cell (GEC) apoptosis are crucial events during stomach carcinoma transformation. PUMA is a potent proapoptotic Bcl-2 protein and mediates acute tissue injury. In this study, we aimed to investigate the role of PUMA in GEC apoptosis and inflammation induced by H. pylori infection. As a result, we found that PUMA expression was elevated in gastritis tissues compared with uninvolved tissues, and it was correlated with the severity of apoptosis and gastritis. In mice, PUMA mRNA and protein were markedly induced in GECs upon induction of gastritis by H. pylori. PUMA-deficient mice were highly resistant to apoptosis and gastritis induced by H. pylori. Furthermore, the transcription factor NF-κB p65 binds to PUMA promoter to activate PUMA transcription after H. pylori infection. In addition, NF-κB inhibitor could rescue H. pylori-induced apoptosis and gastritis. Finally, H. pylori-induced activation of p-p65 and PUMA was mediated via Toll-like receptor 2 (TLR2) and blocked in TLR2 knockout mice. Taken together, these results verified the pro-inflammatory effect of PUMA in H. pylori-infected gastric tissue. Moreover, TLR2/NF-κB-mediated transcriptional regulation of PUMA contributes to the pathogenesis of H. pylori-infected gastritis.

miR-1269b Drives Cisplatin Resistance of Human Non-Small Cell Lung Cancer via Modulating the PTEN/PI3K/AKT Signaling Pathway.

BACKGROUND: MiRNAs have been reported to induce certain drug resistance in multiple solid tumors via various mechanisms. Our study aimed to investigate whether miRNA-1269b was involved in the chemoresistance and the progression of non-small cell lung cancer (NSCLC). METHODS: MTT and colony formation assay were conducted to determine cell proliferation and cell apoptosis was analyzed by flow cytometry with annexin V/PI. Luciferase reporter assay was performed to validate miRNA-targeting sequences. The function of miR-1269b in cisplatin-resistant was evaluated in vivo in a mouse tumor model. RESULTS: We found that miR-1269b expression was up-regulated in cisplatin-resistant NSCLC specimens and NSCLC cell lines, which resulted in the promotion of chemoresistance and tumorigenicity. miR-1269b overexpression enhanced drug resistance and promoted cell proliferation in vitro and tumor growth in vivo, with reduced apoptosis rate of A549 cells inin vitro cell culture. Mechanistically, we identified PTEN as the direct target of miR-1269b, and the PTEN level was negatively correlated with miR-1269b in NSCLC specimens. Further study demonstrated that miR-1269b targeted PTEN to modulate PI3K/AKT signaling pathway. CONCLUSION: In conclusion, these findings suggest that the miR-1269b/PTEN/PI3K/AKT-mediated network might promote cisplatin resistance in NSCLC, and that miR-1269b can be a potential therapeutic target for chemoresistance in NSCLC patients.

Association Of Initial Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Treatment And EGFR Exon 19 Deletion With Frequency Of The T790M Mutation In Non-Small Cell Lung Cancer Patients After Resistance To First-Line Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors.

BACKGROUND: The present study analyzed the relationship between clinical features and the T790M mutation in non-small cell lung cancer (NSCLC) patients resistant to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) treatment. METHODS: NSCLC patients with resistance to first-generation EGFR-TKIs in which the disease control time was more than 6 months after initial TKI treatment were enrolled. T790M mutation analysis was performed using one of the following methods according to each manufacturer's protocols: Cobas EGFR mutation test (41/105, 39.0%), digital PCR (42/105, 40.0%) or Scorpion amplification refractory mutation system (ARMS) (22/105, 21.0%). Sample type of T790M was from tissue only (53/105, 50.5%), plasma only (46/105, 43.8%), tissue and plasma (6/105, 5.7%). RESULTS: Of 105 patients, 57 were T790M-positive and 48 were T790M-negative. T790M-positive patients had longer progression-free survival (PFS) after initial EGFR-TKI treatment (p = 0.019). T790M positivity was more frequent in patients treated with gefitinib than in those treated with icotinib (65% vs 40.54%, p = 0.018). The rate of T790M positivity was lower in patients with EGFR L858R (44.44%, 12/27) before TKI treatment than in those with EGFR 19del (72.0%, 36/50, p = 0.036). Patients who achieved PR after initial EGFR-TKI treatment had a higher rate of T790M positivity than those with SD (75.76% vs 50%, p = 0.023). There was no relationship between T790M status and age, gender, primary site, metastasis site, or treatment before TKI. CONCLUSION: Progression-free survival (PFS), drug type, response to initial EGFR-TKI treatment, and EGFR status before initial EGFR treatment were associated with the frequency of T790M mutation.

Long non-coding RNA LOC554202 promotes acquired gefitinib resistance in non-small cell lung cancer through upregulating miR-31 expression.

Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation inevitably have a relapse due to the occurrence of acquired resistance, resulting in treatment failure. However, little is known about the mechanisms of acquired resistance of NSCLC patients. Here, we elucidated the expression pattern of LOC554202 and miR-31, and their biological functions and mechanisms in NSCLC with acquired EGFR TKI resistance to gefitinib. In the present study, we observed that LOC554202 and miR-31 promoted proliferation and clonogenic growth of gefitinib-resistant NSCLC cells in vitro. LOC554202 upregulated miR-31 expression and they both reduced sensitivity of NSCLC cells to gefitinib. In a xenograft mice model, we found that knockdown of miR-31 significantly repressed gefitinib-resistant NSCLC cells growth in vivo. Furthermore, both LOC554202 and miR-31 levels were significantly increased in NSCLC patients acquiring resistance to gefitinib, and the expression of LOC554202 was positively correlated with the expression of miR-31. By luciferase reporter assays, we identified RAS P21 Protein Activator 1 (RASA1) and Hypoxia Inducible Factor 1 Subunit Alpha Inhibitor (FIH-1) as direct targets of miR-31 in NSCLC cells. Mechanistically, miR-31 directly repressed RASA1 and FIH-1 expression, and thus, at least partially activated the RAF-MEK-ERK and PI3K-AKT signaling pathways in NSCLC with acquired resistance to gefitinib. In conclusion, these data will help us develop potential therapeutic targets for the diagnosis and treatment of acquired EGFR TKI resistance in EGFR-mutant NSCLC.

Delivery of platelet TPM3 mRNA into breast cancer cells via microvesicles enhances metastasis.

Platelets are implicated in the pathophysiology of breast and other cancers through their role in exchanging biomolecules with tumor cells in the tumor microenvironment. Such exchange results in tumor-educated platelets with altered RNA expression profiles. Multiple lines of evidence indicate that platelet RNA profiles may be suitable as diagnostic biomarkers for cancer-related biological processes. In this study, we characterized the gene expression signatures of platelets in breast cancer (BC) by high-throughput sequencing and quantitative real-time RT-PCR. Our results indicate that the expression of TPM3 (tropomyosin 3) mRNA is significantly elevated in platelets from patients with BC compared with age-matched healthy control subjects. Furthermore, up-regulation of TPM3 mRNA in platelets was found to be significantly correlated with metastasis in patients with BC. Finally, we report that platelet TPM3 mRNA is delivered into BC cells through microvesicles and leads to enhanced migrative phenotype of BC cells. In summary, our findings suggest that the transfer of platelet TPM3 mRNA into cancer cells via microvesicles promotes cancer cell migration, and thus platelet-derived TPM3 mRNA may be a suitable biomarker for early diagnosis of metastatic BC.

IL-22 Confers EGFR-TKI Resistance in NSCLC via the AKT and ERK Signaling Pathways.

Background: The efficacy of an EGFR-targeted treatment strategy for non-small cell lung cancer (NSCLC) is reduced by drug resistance. IL-22 enhances tumor growth and induces chemotherapy resistance in human lung cancer cells. The present study elucidated the IL-22-induced mechanism underlying EGFR-tyrosine kinase inhibitor (TKI) resistance in NSCLC. Methods: The plasma and tissues of patients who received EGFR-TKIs were utilized to determine the association between IL-22 expression and gefitinib efficacy. The IL-22 effect on the EGFR/ERK/AKT pathways in NSCLC HCC827 and PC-9 cells was determined using the CCK-8 assay, western blot, and flow cytometric analysis. A PC-9 xenograft model of IL-22 exposure was established. Gefitinib was administered to mice in combination with IL-22 or vehicle. Results: We showed that IL-22 expression was higher in the EGFR-TKI-resistant group compared to EGFR-TKI-sensitive group. IL-22 expression was associated with EGFR-TKI efficacy in plasma. Additional treatment of IL-22 induced gefitinib resistance and reduced apoptosis in PC-9 and HCC827 cell lines. Furthermore, we showed that the effects of IL-22 attributed to p-ERK, p-EGFR, and p-AKT up-regulation. IL-22 neutralizing antibody completely abrogated the effects of IL-22 on apoptosis and AKT/EGFR/ERK signaling. Finally, we showed that IL-22 enhanced tumor growth and induced gefitinib resistance in the PC-9 xenograft model. Moreover, compared with gefitinib alone, the combination of IL-22 and gefitinib led to an increase in Ki67-positive staining and a reduction in TUNEL staining. Conclusions: Our findings indicate that IL-22 plays a role in tumor progression and EGFR-TKI resistance in NSCLC. Thus, IL-22 might serve as a novel biomarker to overcome resistance of EGFR-TKI.

A panel of miRNAs derived from plasma extracellular vesicles as novel diagnostic biomarkers of lung adenocarcinoma.

Lung cancer is the leading cause of cancer-related morbidity and mortality worldwide, with lung adenocarcinoma (LUAD) being the most common histological subtype (approximately 40%). In the absence of reliable screening biomarkers for early diagnosis, most patients with LUAD are inevitably diagnosed at an advanced stage. MicroRNAs (miRNAs) encapsulated within plasma-derived extracellular vesicles (EVs) may be suitable for use as noninvasive diagnostic biomarkers for aggressive malignancies, including LUAD. In this study, we first investigated the miRNA profiles of plasma-derived EVs from LUAD patients and healthy donors, and then systematically evaluated the expression patterns of selected plasma-derived EV miRNAs in a large cohort of patients with LUAD and healthy controls. Notably, we observed that miR-451a, miR-194-5p, and miR-486-5p were significantly increased in EVs from LUAD patients, compared to healthy controls. The area under the curve values for the three miRNAs were 0.9040 (95% confidence interval [CI], 0.8633-0.9447) for miR-451a, 0.7492 (95% CI, 0.6992-0.7992) for miR-194-5p, and 0.9574 (95% CI, 0.9378-0.9769) for miR-486-5p, while the AUC of the combination of these three miRNAs was 0.9650. Thus, these results suggest that these EV miRNAs may be promising candidates for the development of highly effective, noninvasive biomarkers for early LUAD diagnosis.

Identification of Germline Mismatch Repair Gene Mutations in Lung Cancer Patients With Paired Tumor-Normal Next Generation Sequencing: A Retrospective Study.

Background: Paired tumor-normal targeted next-generation sequencing (NGS) is primarily used to identify actionable somatic mutations, but can also detect germline variants including pathogenic germline mutations in DNA mismatch repair (MMR) genes that underlie Lynch syndrome. In the present study we examined paired NGS data from lung cancer patients to identify germline mutations in MMR genes. As lung cancer is not one of the recognized Lynch syndrome-associated neoplasms, we also investigated whether these lung cancer cases are due to Lynch syndrome or are instead sporadic cancers occurring in Lynch syndrome patients. Methods: A retrospective study of 1,179 lung cancer patients with available paired NGS data was performed to identify germline mutations in the MMR genes MLH1, MSH2, MSH6, and PMS2, and evaluate tumor mutation burden (TMB). Microsatellite instability (MSI) testing was done on select cases with MMR gene mutations by either NGS or PCR/capillary electrophoresis approach. Immunohistochemistry (IHC) for MMR proteins was performed in select patients. Results: Pathogenic or likely-pathogenic germline mutations in PMS2, MSH2, or MSH6 were detected in 0.5% (6/1,179) of lung cancer patients; three of the patients had a family history of colon or gastric cancer. The median age at diagnosis of these cases was 68.5 years old. None of these six patients exhibited MSI or loss of MMR protein expression. Among them, no second hit somatic mutations in MMR genes (including single-nucleotide variants, small insertions or deletions and copy number alterations) were detected, and the median TMB was 4.5 muts/MB. Subsequent genetic testing of family members identified new Lynch syndrome cases in two first-degree relatives. Conclusion: These data imply that lung cancers in Lynch syndrome patients are unrelated to the underlying Lynch syndrome diagnosis and occur spontaneously. Nonetheless, paired tumor-normal NGS can identify germline mutations to help reveal Lynch syndrome in cancer patients. This has important implications for cancer screening and risk reduction in these patients and their families.