Tumor‐derived exosomal proteins as diagnostic biomarkers in non‐small cell lung cancer

Accumulating evidence supports a role for exosomal protein in diagnosis. The purpose of this study was to identify the tumor‐derived exosomal biomarkers in the serum that improve the diagnostic value in Chinese non‐small cell lung cancer (NSCLC) patients. Serum exosomes were isolated from healthy donors (n = 46) and NSCLC patients (n = 125) by ultracentrifugation and were characterized using transmission electron microscopy, qNano, and immunoblotting. Proteomic profiles (by mass spectrometry) revealed multiple differentially expressed proteins in the healthy and NSCLC groups. The exosomal expression levels of alpha‐2‐HS‐glycoprotein (AHSG) and extracellular matrix protein 1 (ECM1) increased significantly in the NSCLC patients compared to the healthy group. Alpha‐2‐HS‐glycoprotein showed diagnostic values with a maximum area under the receiver operating characteristic curve (AUC) as 0.736 for NSCLC vs healthy individuals (P < .0001) and 0.682 for early stage NSCLC vs healthy individuals (P < .01). Extracellular matrix protein 1 showed the diagnostic capacity with AUC values of 0.683 (P < .001) and 0.656 (P < .05) in cancer and early stage NSCLC compared to healthy individuals. When AHSG was combined with ECM1, the AUCs were 0.795 and 0.739 in NSCLC and early stage patients, respectively. Taken together, the combination of AHSG, ECM1, and carcinoembryonic antigen improved the diagnostic potential of NSCLC. The diagnosis values were AUC of 0.938 for NSCLC and 0.911 for early stage NSCLC vs healthy individuals. Our results suggest that novel proteomic signatures found in serum exosomes of NSCLC patients show potential usefulness as diagnostic tools.     

脂肪间充质干细胞分泌的Exosome促进结肠癌细胞系上皮间质转化

目的：研究间充质干细胞（mesenchymal stem cell,MSC）来源的Exosome对结肠癌细胞系HCT8上皮间质转化（epithelial mesenchymal transition,EMT）的影响。方法从人脂肪组织中分离出MSC后,对MSC进行培养并传代,并对MSC的分化能力进行鉴定。在人脂肪来源的MSC中提取Exosome后,用透射电子显微镜观察并拍照,并用蛋白质印迹法检测其抗原表达情况。在HCT8培养体系中加入人脂肪来源的MSC分泌的Exosome ,定量PCR和蛋白质印迹法检测上皮和间质转化相关标志物的表达,细胞侵袭和迁移实验检测人脂肪来源的MSC分泌的Exosome对HCT8迁移和侵袭的影响。结果人脂肪来源的MSC具有多系分化能力,人脂肪来源的Exosome直径为40～100 nm ,表达CD63、HSP70和HSP90,下调HCT8上皮相关标志E-cadherin和ZO-1的表达,上调间质相关标志Fibronectin的表达,促进HCT8的迁移和侵袭。结论人脂肪来源的MSC分泌的Exosome可促进结肠癌细胞系HCT8的EMT。     

BOK displays cell death‐independent tumor suppressor activity in non‐small‐cell lung carcinoma

As the genomic region containing the Bcl‐2‐related ovarian killer (BOK) locus is frequently deleted in certain human cancers, BOK is hypothesized to have a tumor suppressor function. In the present study, we analyzed primary non‐small‐cell lung carcinoma (NSCLC) tumors and matched lung tissues from 102 surgically treated patients. We show that BOK protein levels are significantly downregulated in NSCLC tumors as compared to lung tissues (p < 0.001). In particular, we found BOK downregulation in NSCLC tumors of grades two (p = 0.004, n = 35) and three (p = 0.031, n = 39) as well as in tumors with metastases to hilar (pN1) (p = 0.047, n = 31) and mediastinal/subcarinal lymph nodes (pN2) (p = 0.021, n = 18) as opposed to grade one tumors (p = 0.688, n = 7) and tumors without lymph node metastases (p = 0.112, n = 51). Importantly, in lymph node‐positive patients, BOK expression greater than the median value was associated with longer survival (p = 0.002, Mantel test). Using in vitro approaches, we provide evidence that BOK overexpression is inefficient in inducing apoptosis but that it inhibits TGFβ‐induced migration and epithelial‐to‐mesenchymal transition (EMT) in lung adenocarcinoma‐derived A549 cells. We have identified epigenetic mechanisms, in particular BOK promoter methylation, as an important means to silence BOK expression in NSCLC cells. Taken together, our data point toward a novel mechanism by which BOK acts as a tumor suppressor in NSCLC by inhibiting EMT. Consequently, the restoration of BOK levels in low‐BOK‐expressing tumors might favor the overall survival of NSCLC patients.     

Whole blood FPR1 mRNA expression predicts both non‐small cell and small cell lung cancer

While long‐term survival rates for early‐stage lung cancer are high, most cases are diagnosed in later stages that can negatively impact survival rates. We aim to design a simple, single biomarker blood test for early‐stage lung cancer that is robust to preclinical variables and can be readily implemented in the clinic. Whole blood was collected in PAXgene tubes from a training set of 29 patients, and a validation set of 260 patients, of which samples from 58 patients were prospectively collected in a clinical trial specifically for our study. After RNA was extracted, the expressions of FPR1 and a reference gene were quantified by an automated one‐step Taqman RT‐PCR assay. Elevated levels of FPR1 mRNA in whole blood predicted lung cancer status with a sensitivity of 55% and a specificity of 87% on all validation specimens. The prospectively collected specimens had a significantly higher 68% sensitivity and 89% specificity. Results from patients with benign nodules were similar to healthy volunteers. No meaningful correlation was present between our test results and any clinical characteristic other than lung cancer diagnosis. FPR1 mRNA levels in whole blood can predict the presence of lung cancer. Using this as a reflex test for positive lung cancer screening computed tomography scans has the potential to increase the positive predictive value. This marker can be easily measured in an automated process utilizing off‐the‐shelf equipment and reagents. Further work is justified to explain the source of this biomarker.     

Relationship between epithelial to mesenchymal transition and chemoresistance of lung cancer

Objective： The aim of this study was to explore the correlation between epithelial to mesenchymal transition （EMT） and chemoresistance of non-small-cell lung cancer （NSCLC）. Methods： In vitro, the drug resistance index of cisplatin resistant lung adenocarcinoma cell line （A549/DDP） was detected by CCK-8 assay; the morphological change between A549/ DDP cells and lung adenocarcinoma cells （A549） was observed by phase contrast microscope; expression of EMT markers （including E-cadherin and vimentin） and resistance protein, excision repair cross-complementing 1 （ERCC1） was detected by immunocytochemistry. The expression of E-cadherin, vimentin and ERCC1 was investigated by immunohistochemistry in 120 cases of NSCLC, half of that were treated with pre-operative neoadjuvant chemotherapy （neoadjuvant chemotherapy group）, and the other underwent surgery alone （simple surgery group）. Results： There was a significant difference between the ICso （half maximal inhibitory concentration） of A549/DDP cells （5.20） and A549 cells （1.88） （P 〈 0.05）, and the drug resistance index of A549/DDP cells was 2.77. Compared with A549 cells, A549/DDP cells increased expression of ERCC1 （P 〈 0.05）. Moreover, A549/DDP cells showed morphological and phenotypic changes consistent with EMT： with spindle-shaped morphology, and decreased expression of E-cadherin and increased expression of vimentin. Immunohistochemistry showed significant positive correlation between the expression of ERCCI and vimentin （r = 0.496, 0.332, P 〈 0.05）, and significant negative correlation between the ERCCI and E-cadherin （r = -0.403, -0.295, P 〈 0.05） in neoadjuvant chemotherapy group and simple surgery group. In addition, compared with simple surgery group, the expression of ERCC1 （P = 0.003） and vimentin （P = 0.004） was significantly increased, and the expression of E-cadherin was decreased in neoadjuvant chemotherapy group （P = 0.032）. Cenclusion： A549/DDP cells acquired cisplatin-resistance and occurred EMT simultaneously; the phenomenon of chemoresistance and EMT was caused more easily in neoadjuvant chemotherapy group. As such, we further confirmed the close correlation between chemoresistance and EMT of NSCLC, and provided theoretical basis for the targeting therapy with EMT regulatory factor for chemoresistant NSCLC patients.     

Patient‐derived xenograft models of non‐small cell lung cancer for evaluating targeted drug sensitivity and resistance

Patient‐derived xenograft (PDX) models are a useful tool in cancer biology research. However, the number of lung cancer PDX is limited. In the present study, we successfully established 10 PDX, including three adenocarcinoma (AD), six squamous cell carcinoma (SQ) and one large cell carcinoma (LA), from 30 patients with non‐small cell lung cancer (NSCLC) (18 AD, 10 SQ, and 2 LA), mainly in SCID hairless outbred (SHO) mice (Crlj:SHO‐Prkdc^scidHr^hr). Histology of SQ, advanced clinical stage (III‐IV), status of lymph node metastasis (N2‐3), and maximum standardized uptake value ≥10 when evaluated using a delayed ¹⁸F‐fluoro‐2‐deoxy‐d ‐glucose positron emission tomography (FDG‐PET) scan was associated with successful PDX establishment. Histological analyses showed that PDX had histology similar to that of patients’ surgically resected tumors (SRT), whereas components of the microenvironment were replaced with murine cells after several passages. Next‐generation sequencing analyses showed that after two to six passages, PDX preserved the majority of the somatic mutations and mRNA expressions of the corresponding SRT. Two out of three PDX with AD histology had epidermal growth factor receptor (EGFR) mutations (L858R or exon 19 deletion) and were sensitive to EGFR tyrosine kinase inhibitors (EGFR‐TKI), such as gefitinib and osimertinib. Furthermore, in one of the two PDX with an EGFR mutation, osimertinib resistance was induced that was associated with epithelial‐to‐mesenchymal transition. This study presented 10 serially transplantable PDX of NSCLC in SHO mice and showed the use of PDX with an EGFR mutation for analyses of EGFR‐TKI resistance.     

Human immunodeficiency virus Tat‐TIP30 interaction promotes metastasis by enhancing the nuclear translocation of Snail in lung cancer cell lines

Lung cancer patients with human immunodeficiency virus (HIV) have a poorer prognosis than do patients without HIV infection. HIV1 Tat is a secreted viral protein that penetrates the plasma membrane and interacts with a number of proteins in non‐HIV‐infected cells. The loss of function of Tat‐interacting protein 30 (TIP30) has been linked to metastasis in non‐small cell lung cancer (NSCLC). However, it is unknown how the interaction of HIV1 Tat with TIP30 regulates the metastasis of NSCLC cells. In this study, the overexpression of TIP30 decreased tumor growth factor‐β‐induced epithelial‐to‐mesenchymal transition (EMT) and invasion of NSCLC cells, whereas the knockdown of TIP30 promoted EMT, invasion and stemness. Exposure to recombinant HIV1 Tat proteins promoted EMT and invasion. A mechanistic study showed that the interaction of HIV1 Tat with TIP30 blocked the binding of TIP30 to importin‐β, which is required for the nuclear translocation of Snail. Indeed, the loss of TIP30 promoted the nuclear translocation of Snail. In vivo studies demonstrated that the overexpression of TIP30 inhibited the metastasis of NSCLC cells. In contrast, the coexpression of HIV1 Tat and TIP30 diminished the inhibitory effect of TIP30 on metastasis. Immunohistochemistry confirmed that TIP30 overexpression reduced the nuclear localization of Snail, whereas the coexpression of HIV1 Tat and TIP30 increased nuclear Snail in metastatic tumors. In conclusion, the binding of HIV1 Tat to TIP30 enhanced EMT and metastasis by regulating the nuclear translocation of Snail. Targeting Tat‐interacting proteins may be a potential therapeutic strategy to prevent metastasis in NSCLC patients with HIV infection.     

Acquisition of cancer stem cell‐like properties in non‐small cell lung cancer with acquired resistance to afatinib

Afatinib is an irreversible epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitor (TKI) that is known to be effective against the EGFR T790M variant, which accounts for half of the mechanisms of acquired resistance to reversible EGFR‐TKIs. However, acquired resistance to afatinib was also observed in clinical use. Thus, elucidating and overcoming the mechanisms of resistance are important issues in the treatment of non‐small cell lung cancer. In this study, we established various afatinib‐resistant cell lines and investigated the resistance mechanisms. EGFR T790M mutations were not detected using direct sequencing in established resistant cells. Several afatinib‐resistant cell lines displayed MET amplification, and these cells were sensitive to the combination of afatinib plus crizotinib. As a further investigation, a cell line that acquired resistance to afatinib plus crizotinib, HCC827‐ACR, was established from one of the MET amplified‐cell lines. Several afatinib‐resistant cell lines including HCC827‐ACR displayed epithelial‐to‐mesenchymal transition (EMT) features and epigenetic silencing of miR‐200c, which is a suppresser of EMT. In addition, these cell lines also exhibited overexpression of ALDH1A1 and ABCB1, which are putative stem cell markers, and resistance to docetaxel. In conclusion, we established afatinib‐resistant cells and found that MET amplification, EMT, and stem cell‐like features are observed in cells with acquired resistance to EGFR‐TKIs. This finding may provide clues to overcoming resistance to EGFR‐TKIs.     

Comparison of gefitinib,erlotinib and afatinib in non‐small cell lung cancer: A meta‐analysis

Gefitinib, erlotinib and afatinib are three widely used epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) for treating advanced non‐small cell lung cancer (NSCLC) with proven efficacy. We undertook a systematic review and meta‐analysis to synthesize existing studies with direct comparisons of EGFR TKIs in NSCLC in terms of both efficacy and safety. Eight randomized trials and 82 cohort studies with a total of 17,621 patients were included for analysis. Gefitinib and erlotinib demonstrated comparable effects on progression‐free survival (hazard ratio [HR], 1.00; 95% confidence interval [CI], 0.95 to 1.04), overall survival (HR, 0.99; 95% CI, 0.93 to 1.06), overall response rate (risk ratio [RR], 1.05; 95% CI, 1.00 to 1.11), and disease control rate (RR, 0.98; 95% CI, 0.96 to 1.01), which did not vary considerably with EGFR mutation status, ethnicity, line of treatment, and baseline brain metastasis status. Gefitinib was associated with more grade 3/4 liver dysfunction, but tended to cause lower rates of dose reduction, treatment discontinuation, total grade 3/4 adverse events (RR, 0.78; 95% CI 0.65 to 0.94), and a number of specific adverse events such as rash and diarrhea. No solid evidence was found that afatinib had greater efficacy than gefitinib or erlotinib in first‐line treatment of EGFR‐mutant NSCLC. However, afatinib was more effective than erlotinib as second‐line treatment of patients with advanced squamous cell carcinoma. The grade 3/4 adverse events rate of afatinib was comparable to that of erlotinib but higher than that of gefitinib.     

Synergistic activity of sorafenib and betulinic acid against clonogenic activity of non‐small cell lung cancer cells

The highly selective multi‐targeted agent sorafenib is an inhibitor of a number of intracellular signaling kinases with anti‐proliferative, anti‐angiogenic and pro‐apoptotic effects in various types of tumors, including human non‐small cell lung cancer (NSCLC). Betulin displays a broad spectrum of biological and pharmacological properties, including anticancer and chemopreventive activity. Combination of drugs with different targets is a logical approach to overcome multilevel cross‐stimulation among key signaling pathways in NSCLC progression. NSCLC cell lines, A549, H358 and A427, with different KRAS mutations, and normal human peripheral blood lymphocyte cells, were treated with sorafenib and betulinic acid alone and in combination. We examined the effect of different combined treatments on viability (MTS test), proliferation and apoptotic susceptibility based on flow cytometry, alterations in signaling pathways by western blotting and colony‐forming ability. The combination of sorafenib with betulinic acid had a strong effect on the induction of apoptosis of different NSCLC cell lines. In addition, this combination was not toxic for human peripheral blood lymphocytes. Combination treatment changed the expression of proteins involved in the mitochondrial apoptosis pathway and induced apoptotic death by caspase activation. Importantly, combination treatment with low drug concentrations tremendously reduced the colony‐forming ability of A549, H358 and A427 cells, as compared to both compounds alone. In this study, we showed that combination therapy with low concentrations of sorafenib and betulinic acid had the capacity to induce high levels of cell death and abolish clonogenic activity in some NSCLC cell lines regardless of KRAS mutations.     

The presence of Merkel cell polyomavirus is associated with deregulated expression of BRAF and Bcl‐2 genes in non‐small cell lung cancer

Polyomaviruses such as BK virus (BKV), JC virus (JCV) and Merkel cell polyomavirus (MCPyV) are typically nononcogenic, although they have been detected in a variety of human neoplasms. The aim of our study was to determine the frequency of the most common polyomaviruses MCPyV, BKV and JCV as well as the gene expression profile of genes involved in oncogenesis including K‐ras, BRAF, RKIP, Bax, Bcl‐2, p53 and RB1 in a cohort of non‐small cell lung cancer (NSCLC) patients. Real‐time and nested polymerase chain reaction (PCR) were used to assess the presence of polyomaviruses DNA in tissue biopsies from 110 patients with primary NSCLC and 14 tissue specimens from macroscopically healthy sites of their lung. Real‐time PCR was also used to determine the mRNA expression of K‐ras, BRAF, RKIP, Bax, Bcl‐2, p53 and RB1 in selected samples. Results showed that ten NSCLC specimens were positive for the presence of MCPyV DNA (10/110, 9.1%), whereas no control sample was tested positive for the virus. The MCPyV‐positive samples were predominantly obtained from male smokers (9/10). BKV and JCV DNA were not detected either in lung tissues biopsies or the control specimens. Interestingly, gene expression analysis revealed increased mRNA and protein expression of BRAF gene in association with BRAF phosphorylation in the MCPyV‐positive samples, whereas Bcl‐2 gene expression was downregulated in the same type of samples. The detected MCPyV prevalence in NSCLC in combination with the deregulated expression of BRAF and Bcl‐2 genes suggests that these events are likely to contribute to the pathogenesis of NSCLC.     

The sphingosine kinase 2 inhibitor ABC294640 displays anti‐non‐small cell lung cancer activities in vitro and in vivo

Non‐small cell lung cancer (NSCLC) accounts for about 85‐90% of lung cancer cases, and is the number one killer among cancers in the United States. The majorities of lung cancer patients do not respond well to conventional chemo‐ and/or radio‐therapeutic regimens, and have a dismal 5‐year survival rate of ～15%. The recent introduction of targeted therapy and immunotherapy gives new hopes to NSCLC patients, but even with these agents, not all patients respond, and responses are rarely complete. Thus, there is still an urgent need to identify new therapeutic targets in NSCLC and develop novel anti‐cancer agents. Sphingosine kinase 2 (SphK2) is one of the key enzymes in sphingolipid metabolism. SphK2 expression predicts poor survival in NSCLC patients, and is associated with Gefitinib‐resistance. In this study, the anti‐NSCLC activities of ABC294640, the only first‐in‐class orally available inhibitor of SphK2, were explored. The results obtained indicate that ABC294640 treatment causes significant NSCLC cell apoptosis, cell cycle arrest and suppression of tumor growth in vitro and in vivo. Moreover, lipidomics analyses revealed the complete signature of ceramide and dihydro(dh)‐ceramide species in the NSCLC cell‐lines with or without ABC294640 treatment. These findings indicate that sphingolipid metabolism targeted therapy may be developed as a promising strategy against NSCLC.