Non-small-cell lung cancer: molecular targeted therapy and personalized medicine - drug resistance, mechanisms, and strategies

Recent advances in molecular targeted therapy of lung cancer: Possible application in translation medicine

Lung cancer is one of the leading causes of death among all cancer deaths. This cancer is classified into two different histological subtypes: non-small cell lung cancer (NSCLC), which is the most common subtype, and small cell lung cancer (SCLC), which is the most aggressive subtype. Understanding the molecular characteristics of lung cancer has expanded our knowledge of the cellular origins and molecular pathways affected by each of these subtypes and has contributed to the development of new therapies. Traditional treatments for lung cancer include surgery, chemotherapy, and radiotherapy. Advances in understanding the nature and specificity of lung cancer have led to the development of immunotherapy, which is the newest and most specialized treatment in the treatment of lung cancer. Each of these treatments has advantages and disadvantages and causes side effects. Today, combination therapy for lung cancer reduces side effects and increases the speed of recovery. Despite the significant progress that has been made in the treatment of lung cancer in the last decade, further research into new drugs and combination therapies is needed to extend the clinical benefits and improve outcomes in lung cancer. In this review article, we discussed common lung cancer treatments and their combinations from the most advanced to the newest.

The prognostic landscape of genes and infiltrating immune cells in cytokine induced killer cell treated-lung squamous cell carcinoma and adenocarcinoma

OBJECTIVE

Patients with non-small cell lung cancer (NSCLC) respond differently to cytokine-induced killer cell (CIK) treatment. Therefore, potential prognostic markers to identify patients who would benefit from CIK treatment must be elucidated. The current research aimed at identifying predictive prognostic markers for efficient CIK treatment of patients with NSCLC.

METHODS

Patients histologically diagnosed with NSCLC were enrolled from the Tianjin Medical University Cancer Institute and Hospital. We performed whole-exome sequencing (WES) on the tumor tissues and paired adjacent benign tissues collected from 50 patients with NSCLC, and RNA-seq on tumor tissues of 17 patients with NSCLC before CIK immunotherapy treatment. Multivariate Cox proportional hazard regression analysis was used to analyze the association between clinical parameters and prognostic relevance. WES and RNA-seq data between lung squamous cell carcinoma (SCC) and adenocarcinoma (Aden) were analyzed and compared.

RESULTS

The pathology subtype of lung cancer was the most significantly relevant clinical parameter associated with DFS, as analyzed by multivariate Cox proportional hazard regression (P = 0.031). The patients with lung SCC showed better CIK treatment efficacy and extended DFS after CIK treatment. Relatively low expression of HLA class II genes and checkpoint molecules, and less immunosuppressive immune cell infiltration were identified in the patients with lung SCC.

CONCLUSIONS

Coordinated suppression of the expression of HLA class II genes and checkpoint molecules, as well as less immune suppressive cell infiltration together contributed to the better CIK treatment efficacy in lung SCC than lung Aden.

INSL4 as prognostic marker for proliferation and invasiveness in Non-Small-Cell Lung Cancer

Non-small-cell-lung cancer accounts for 80-85% of all forms of lung cancer as leading cause of cancer-related death in human. Despite remarkable advances in the diagnosis and therapy of lung cancer, no significant improvements have thus far been achieved in terms of patients' prognosis. Here, we investigated the role of INSL4 - a member of the relaxin-family - in NSCLC. We overexpressed INSL4 in NSCLC cells to analyse in vitro the growth rate and the tumourigenic features. We investigated the signalling pathways engaged in INSL4 overexpressing cells and the tumour growth ability by studying the tumour development in a patient derived tumour xenograft mouse model. We found an INSL4 cell growth promoting effect in vitro in H1299 cells and in vivo in NOD/SCID mice. Surprisingly, in NSCLC-A549 cells, INSL4 overexpression has not similar effect, despite huge basal INSL4-mRNA expression respect to H1299. The INSL4-mRNA analysis of eight different NSCLC-derived cell lines, revealed highly difference in the INSL4-mRNA amount. Transfection of NSCLC lines with INSL4-Myc showed huge level of INSL4-mRNA with a very low amount of protein expressed. Notably, similar discrepancy has been observed in NSCLC patients. However, in a cohort of NSCLC patients analysing a database, we found a significant inverse correlation between INSL4 expression and Overall Survival. By combining the in vitro and in vivo results, suggest that in patients whose NSCLC adenocarcinoma spontaneously expressed high levels of INSL4 post-transcriptional modifications affecting INSL4 do not allow to assess precision therapy in selected patients without consider protein INSL4 amount.

Chrysin enhances anticancer drug-induced toxicity mediated by the reduction of claudin-1 and 11 expression in a spheroid culture model of lung squamous cell carcinoma cells

The aberrant expression of claudins (CLDNs), which are tight junctional proteins, is seen in various solid tumors, but the regulatory mechanisms and their pathophysiological role are not well understood. Both CLDN1 and CLDN11 were highly expressed in human lung squamous cell carcinoma (SCC). Chrysin, found in high concentration in honey and propolis, decreased CLDN1 and CLDN11 expression in RERF-LC-AI cells derived from human lung SCC. The phosphorylation level of Akt was decreased by chrysin, but those of ERK1/2 and c-Jun were not. LY-294002, an inhibitor of phosphatidylinositol 3-kinase, inhibited the phosphorylation of Akt and decreased the expression levels of CLDN1 and CLDN11. The association between phosphoinositide-dependent kinase 1 (PDK1) and Akt was inhibited by chrysin, but the phosphorylation of PDK1 was not. Immunoprecipitation and quartz-crystal microbalance assays revealed that biotinylated-chrysin binds directly to Akt. The knockdown of CLDN1 and CLDN11 using small interfering RNAs increased the transepithelial flux of doxorubicin (DXR), an anthracycline anticancer drug. Similarly, both chrysin and LY-294002 increased DXR flux. Neither CLDN1 knockdown, CLDN11 knockdown, nor chrysin changed the anticancer drug-induced cytotoxicity in a two-dimensional culture model, whereas they enhanced cytotoxicity in a spheroid culture model. Taken together, chrysin may bind to Akt and inhibit its phosphorylation, resulting in the elevation of anticancer drug-induced toxicity mediated by reductions in CLDN1 and CLDN11 expression in RERF-LC-AI cells. We suggest that chrysin may be useful as an adjuvant chemotherapy in lung SCC.

Raddeanin A Induces Apoptosis and Cycle Arrest in Human HCT116 Cells through PI3K/AKT Pathway Regulation In Vitro and In Vivo

This study aimed to investigate the in vitro and in vivo effects of Raddeanin A on apoptosis and the cell cycle in the human colorectal cell line, HCT116, and to explore the possible underlying mechanisms of action. We found the growth inhibition rate gradually increased as the drug concentration increased via the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, which indicated that Raddeanin A significantly inhibited the growth of HCT116 cells. Flow cytometry (FCM) showed that Raddeanin A concentration-dependently induced apoptosis in HCT116 cells. In addition, the percentage of cells in the G₀/G₁ phase was noticeably increased, which indicated that Raddeanin A blocked cell cycle progression in HCT116 cells and caused arrest in the G₀/G₁ phase. Moreover, the expression of proteins involved in the PI3K/AKT signaling pathway (e.g., p-PI3K and p-AKT) was decreased. The results showed that in vivo revealed that Raddeanin A significantly inhibited tumor growth in an HCT116-xenografted mouse model; apoptotic cells were also detected in the tumor tissue. The expression of the tissue proteins cyclinD1, cyclinE, p-PI3K, and p-AKT was decreased. The above results show that the Raddeanin A exerted a strong antitumor effect in the human colorectal cell line HCT116 both in vitro and in vivo. This effect may be caused by the induction of apoptosis and cycle arrest achieved through PI3K/AKT signaling pathway regulation.

Genetic Association of Drug Response to Erlotinib in Chinese Advanced Non-small Cell Lung Cancer Patients

The efficacy of erlotinib treatment for advanced non-small cell lung cancer (NSCLC) is due to its action as an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Patients treated with erlotinib experience different drug responses. The effect of germline mutations on therapeutic responses and adverse drug responses (ADRs) to erlotinib in Chinese patients requires elucidation. Sixty Han Chinese advanced non-small cell lung cancer patients received erlotinib monotherapy and, for each participant, 76 candidate genes (related to EGFR signaling, drug metabolism and drug transport pathways) were sequenced and analyzed. The single-nucleotide polymorphisms (SNPs) rs1042640 in UGT1A10, rs1060463, and rs1064796 in CYP4F11, and rs2074900 in CYP4F2 were significantly associated with therapeutic responses to erlotinib. Rs1064796 in CYP4F11 and rs10045685 in UGT3A1 were significantly associated with adverse drug reaction. Moreover, analysis of a validation cohort confirmed the significant association between rs10045685 in UGT3A1 and erlotinib adverse drug response(unadjusted p = 0.015). This study provides comprehensive, systematic analyses of genetic variants associated with responses to erlotinib in Chinese advanced non-small cell lung cancer patients. Newly-identified SNPs may serve as promising markers to predict responses and safety in erlotinib-treated advanced non-small cell lung cancer patients after chemotherapy doublet.

Cell death-based treatment of lung adenocarcinoma

The most common type of lung cancer is adenocarcinoma (ADC), comprising around 40% of all lung cancer cases. In spite of achievements in understanding the pathogenesis of this disease and the development of new approaches in its treatment, unfortunately, lung ADC is still one of the most aggressive and rapidly fatal tumor types with overall survival less than 5 years. Lung ADC is often diagnosed at advanced stages involving disseminated metastatic tumors. This is particularly important for the successful development of new approaches in cancer therapy. The high resistance of lung ADC to conventional radiotherapies and chemotherapies represents a major challenge for treatment effectiveness. Here we discuss recent advances in understanding the molecular pathways driving tumor progression and related targeted therapies in lung ADCs. In addition, the cell death mechanisms induced by different treatment strategies and their contribution to therapy resistance are analyzed. The focus is on approaches to overcoming drug resistance in order to improve future treatment decisions.

Ambroxol enhances anti-cancer effect of microtubule-stabilizing drug to lung carcinoma through blocking autophagic flux in lysosome-dependent way

Lung carcinoma has become a more and more serious health problem as platinum-based chemotherapy remains a limited benefit. Accumulating evidences indicate that autophagy plays a significant role in decreased curative effect and chemotherapy failure. Inhibition of autophagy can potentiate anti-proliferation effect and contribute to tumor regression in lung carcinoma. Here, we showed that the expectorant drug ambroxol (Ax) promoted autophagosomes accumulation by blocking late-stage autophagic flux in lung carcinoma cells. Furthermore, Ax treatment caused alkalization of lysosome and impaired lysosomal degradation capacity, which contributed to decreased autophagosomes-lysosomes fusion and interrupted normal cargo degradation. Ax potentiated cell-killing sensitivity of paclitaxel (PTX) and docetaxel (DTX), which had nothing to do with cell uptake but was associated with enhanced autophagy level. Moreover, Ax in combination with PTX exerted a significantly enhanced tumor-shrinking effect and prolonged survival time in subcutaneous and pulmonary metastatic tumor nude mice models. Considering the superiority of lung protection and excellent safety, Ax shows enormous translational potential and preponderance in clinical lung carcinoma therapy. Together, our findings suggested that the novel function of Ax, namely autophagy inhibition, resulted from alkalization and impaired degradation capacity of lysosome. The combination of Ax and PTX showed an enhanced cytotoxicity in vitro and improved satisfactory curative outcome in vivo. Our research provides a promising therapeutic strategy to lung carcinoma, which has clinical transformation potential and practical application value.

Apigenin in cancer therapy: anti-cancer effects and mechanisms of action

Apigenin is a common dietary flavonoid that is abundantly present in many fruits, vegetables and Chinese medicinal herbs and serves multiple physiological functions, such as strong anti-inflammatory, antioxidant, antibacterial and antiviral activities and blood pressure reduction. Therefore, apigenin has been used as a traditional medicine for centuries. Recently, apigenin has been widely investigated for its anti-cancer activities and low toxicity. Apigenin was reported to suppress various human cancers in vitro and in vivo by multiple biological effects, such as triggering cell apoptosis and autophagy, inducing cell cycle arrest, suppressing cell migration and invasion, and stimulating an immune response. In this review, we focus on the most recent advances in the anti-cancer effects of apigenin and their underlying mechanisms, and we summarize the signaling pathways modulated by apigenin, including the PI3K/AKT, MAPK/ERK, JAK/STAT, NF-κB and Wnt/β-catenin pathways. We also discuss combinatorial strategies to enhance the anti-cancer effect of apigenin on various cancers and its use as an adjuvant chemotherapeutic agent to overcome cancer drug resistance or to alleviate other adverse effects of chemotherapy. The functions of apigenin against cancer stem cells are also summarized and discussed. These data demonstrate that apigenin is a promising reagent for cancer therapy. Apigenin appears to have the potential to be developed either as a dietary supplement or as an adjuvant chemotherapeutic agent for cancer therapy.

Insulin-like Growth Factor 1 Receptor Expression in Advanced Non-small-cell Lung Cancer and its Impact on Overall Survival

BACKGROUND

The insulin-like growth factor 1 receptor (IGF1R) expression has been addressed as a potential prognostic marker in non-small-cell lung cancer (NSCLC) in various studies; however, the associations between IGF1R expression and prognosis of advanced NSCLC patients is still controversial. The aim of our observational, cohort study was to evaluate the expression of IGF1R in advanced NSCLC and its prognostic role. A subgroup analysis was performed to address the influence of pre-existing type 2 diabetes mellitus (T2DM) status on IGF1R expression and overall survival (OS).

PATIENTS AND METHODS

IGF1R expression was evaluated in 167 consecutive advanced NSCLC patients (stage IIIB and IV), diagnosed and treated at one university institution, between 2005 and 2010. All patients received at least one line of standard cytotoxic therapy and 18 of them had pre-existing T2DM. IGF1R expression was determined by immunohistochemical (IHC) staining, with score ≥ 1+ considered as positive. Information on baseline characteristics, as well as patients' follow-up data, were obtained from the hospital registry. Associations of IGF1R expression with clinical characteristics and overall survival were compared.

RESULTS

IGF1R expression was positive in 79.6% of patients, significantly more often in squamous-cell carcinoma (SCC) compared to non-squamous-cell (NSCC) histology (88.7% vs. 74.3%; P = 0.03). IGF1R positivity did not correlate with T2DM status or with other clinical features (sex, smoking status, performance status). Median OS was similar between IGF1R positive and IGF1R negative group (10.2 vs. 8.5 months, P = 0.168) and between patients with or without T2DM (8.7 vs. 9.8 months, P = 0.575). Neither IGF1R expression nor T2DM were significant predictors of OS.

CONCLUSIONS

IGF1R or T2DM status were not significantly prognostic in described above collective of advanced NSCLC treated with at least one line of chemotherapy. In addition, no association between T2DM status and IGF1R expression was found. Further studies on IGF1R expression and its prognostic as well as therapeutic consequences in a larger collective of advanced NSCLC patients, with or without T2DM, are needed.

Small interfering RNA targeting S100A4 sensitizes non-small-cell lung cancer cells (A549) to radiation treatment

Objective

This study aimed to investigate the impact of S100A4-small interfering RNA (S100A4-siRNA) on apoptosis and enhanced radiosensitivity in non-small-cell lung cancer (A549) cells. We also explored the mechanisms of radiosensitization and identified a new target to enhance radiosensitivity and gene therapy for non-small-cell lung cancer.

Methods

RNA interference is a powerful tool for gene silencing. In this study, we constructed an effective siRNA to knock down S100A4. A549 cells were randomly divided into three groups: blank, negative control, and S100A4-siRNA. To investigate the effect of S100A4-siRNA, the expression of S100A4, E-cadherin, and p53 proteins and their messenger RNA (mRNA) was detected by Western blot and quantitative real-time polymerase chain reaction. Transwell chambers were used to assess cell invasion. Cell cycle and apoptosis were analyzed by flow cytometry. Radiosensitivity was determined by colony formation ability.

Results

Our results demonstrate that S100A4-siRNA effectively silenced the S100A4 gene. When siRNA against S100A4 was used, S100A4 protein expression was downregulated, whereas the expressions of E-cadherin and p53 were upregulated. In addition, a clear reduction in S100A4 mRNA levels was noted compared with the blank and negative control groups, whereas E-cadherin and p53 mRNA levels increased. Transfection with S100A4-siRNA significantly reduced the invasiveness of A549 cells. S100A4 silencing induced immediate G2/M arrest in cell cycle studies and increased apoptosis rates in A549 cells. In clonogenic assays, we used a multitarget, single-hit model to detect radiosensitivity after S100A4 knockdown. All parameters (D0, Dq, α, β) indicated that the downregulation of S100A4 enhanced radiosensitivity in A549 cells. Furthermore, S100A4-siRNA upregulated p53 expression, suggesting that S100A4 may promote A549 cell proliferation, invasion, and metastasis by regulating the expression of other proteins. Therefore, siRNA-directed S100A4 knockdown may represent a viable clinical therapy for lung cancer.

Conclusion

S100A4 downregulation potentially enhances the sensitivity of human A549 cells to radiotherapy.

Folate receptor-targeted nanoparticle delivery of HuR-RNAi suppresses lung cancer cell proliferation and migration

BACKGROUND

Human antigen R (HuR) is an RNA binding protein that is overexpressed in many human cancers, including lung cancer, and has been shown to regulate the expression of several oncoproteins. Further, HuR overexpression in cancer cells has been associated with poor-prognosis and therapy resistance. Therefore, we hypothesized that targeted inhibition of HuR in cancer cells should suppress several HuR-regulated oncoproteins resulting in an effective anticancer efficacy. To test our hypothesis, in the present study we investigated the efficacy of folate receptor-α (FRA)-targeted DOTAP:Cholesterol lipid nanoparticles carrying HuR siRNA (HuR-FNP) against human lung cancer cells.

RESULTS

The therapeutic efficacy of HuR-FNP was tested in FRA overexpressing human H1299 lung cancer cell line and compared to normal lung fibroblast (CCD16) cells that had low to no FRA expression. Physico-chemical characterization studies showed HuR-FNP particle size was 303.3 nm in diameter and had a positive surface charge (+4.3 mV). Gel retardation and serum stability assays showed that the FNPs were efficiently protected siRNA from rapid degradation. FNP uptake was significantly higher in H1299 cells compared to CCD16 cells indicating a receptor-dose effect. The results of competitive inhibition studies in H1299 cells demonstrated that HuR-FNPs were efficiently internalized via FRA-mediated endocytosis. Biologic studies demonstrated HuR-FNP but not C-FNP (control siRNA) induced G1 phase cell-cycle arrest and apoptosis in H1299 cells resulting in significant growth inhibition. Further, HuR-FNP exhibited significantly higher cytotoxicity against H1299 cells than it did against CCD16 cells. The reduction in H1299 cell viability was correlated with a marked decrease in HuR mRNA and protein expression. Further, reduced expression of HuR-regulated oncoproteins (cyclin D1, cyclin E, and Bcl-2) and increased p27 tumor suppressor protein were observed in HuR-FNP-treated H1299 cells but not in C-FNP-treated cells. Finally, cell migration was significantly inhibited in HuR-FNP-treated H1299 cells compared to C-FNP.

CONCLUSIONS

Our results demonstrate that HuR is a molecular target for lung cancer therapy and its suppression using HuR-FNP produced significant therapeutic efficacy in vitro.

Overexpression of microRNA-133b sensitizes non-small cell lung cancer cells to irradiation through the inhibition of glycolysis

Non-small cell lung cancer (NSCLC) accounts for 85% of all types of lung cancer and is the leading cause of world-wide cancer-associated mortalities. Radiation therapy has long been regarded as a fundamental therapeutic treatment strategy for NSCLC. However, alternative therapies for NSCLC remain insufficient, with the majority of cancers developing a high incidence of radioresistance. MicroRNAs (miRNAs/miRs) are endogenous oligonucleotide RNAs that serve an important role in carcinogenesis and tumor progression. In the present study, a novel function of miR-133b that is associated with the radiosensitivity of lung cancer cells is reported. miR-133 was downregulated in radioresistant lung cancer cells, which exhibited an elevated glycolysis rate when compared with radiosensitive cells. Additionally, it was observed that pyruvate kinase isoform M2 (PKM2) is a target of miR-133b, and that the expression of PKM2 is positively correlated with radioresistance. Finally, it was demonstrated that overexpression of miR-133b resensitizes radioresistant lung cancer cells through the inhibition of PKM2-mediated glycolysis. The current study may indicate a novel function of miR-133b, potentially aiding the development of anticancer therapeutics.

MicroRNA-92a promotes growth, metastasis, and chemoresistance in non-small cell lung cancer cells by targeting PTEN

MicroRNA-92a (miR-92a) has been reported to play important roles in tumorigenesis of human various cancers. However, the roles and underlying molecular mechanism of miR-92a in non-small cell lung cancer (NSCLC) have not been totally elucidated. Therefore, the aims of this study were to determine the role of miR-92a and to elucidate its regulatory mechanism in NSCLC. We found that miR-92a was significantly upregulated in NSCLC tissues compared to matched adjacent normal lung tissues, and its expression is significantly associated with clinical characteristics of patients, including tumor, node, and metastasis (TNM) stage; tumor size; and lymph node metastasis (all P < 0.01). Function assays demonstrated that upregulation of miR-92a in NSCLC cells promoted cell proliferation, migration, and invasion, decreased apoptosis and caspase-3 activity, and enhanced chemoresistance of NSCLC cells, whereas downregulation of miR-92a showed the opposite effects. Moreover, phosphatase and tensin homolog (PTEN), a unique tumor suppressor gene, was confirmed as a direct target of miR-92a, and PTEN messenger RNA (mRNA) expression was decreased in NSCLC tissues and was inversely correlated with miR-92a. Downregulation of PTEN could mimic the same effects of miR-92a mimic in NSCLC cells and rescue the effects on NSCLC cells induced by miR-92a inhibitor. Taken together, these findings suggested that miR-92a could promote growth, metastasis, and chemoresistance in NSCLC cells at least partially by targeting PTEN.

Immune Checkpoint Blockade: A New Paradigm in Treating Advanced Cancer

The approval of the immune checkpoint inhibitor ipilimumab for the treatment of advanced melanoma in 2011 spearheaded the development of other anticancer therapies with immune mechanisms of action, including other immune checkpoint inhibitors. Instead of acting directly on the tumor, these therapies work to "remove the brakes" on the immune system to restore antitumor immune responses. In addition to ipilimumab, which targets the cytotoxic T lymphocyte-associated antigen 4 pathway, several new drugs that target the programmed death-1 pathway are in phase III trials across tumor types, including melanoma, lung cancer, and renal cell carcinoma. In keeping with their unique mechanism of action, these immune checkpoint inhibitors have shown both conventional and unconventional response patterns, including initial apparent tumor progression followed by regression, and adverse events (AEs) that are likely immune-related. Advanced practitioners (APs) treating patients receiving immuno-oncology agents are in a key position to educate patients about expectations with these therapies and to screen patients for AEs and initiate appropriate and timely interventions. This review summarizes current immune checkpoint inhibitor data and provides patient management strategies for APs to optimize patient outcomes with these novel therapies.

Novel Role for γ-Catenin in the Regulation of Cancer Cell Migration via the Induction of Hepatocyte Growth Factor Activator Inhibitor Type 1 (HAI-1)

γ-catenin (Plakoglobin), a well-described structural protein functioning at the adherens junctions and desmosomes, was shown to be either lost or weakly expressed in non-small cell lung cancer (NSCLC) cells and tumor tissues. However, the tumor suppressive affects of γ-catenin were not fully understood. In this study, we have identified a novel role for the affects of γ-catenin on non-small cell lung cancer (NSCLC) cell migration. Expression of γ-catenin in NSCLC cells resulted in reduced cell migration as determined by both scratch assays and trans-well cell migration assays. Moreover, the affects of γ-catenin on cell migration were observed to be p53-dependent. Mechanistically, the anti-migratory effects seen via γ-catenin were driven by the expression of hepatocyte growth factor activator inhibitor Type I (HAI-1 or SPINT-1), an upstream inhibitor of the c-MET signaling pathway. Furthermore, the re-expression of γ-catenin sensitized NSCLC cells to c-MET inhibitor-mediated growth inhibition. Taken together, we identify γ-catenin as a novel regulator of HAI-1, which is a critical regulator of HGF/c-MET signaling. Therefore, targeting γ-catenin-mediated HAI-1 expression might be a useful strategy to sensitize NSCLC to c-MET inhibitors.

Radiosensitizing effect of schinifoline from Zanthoxylum schinifolium Sieb et Zucc on human non-small cell lung cancer A549 cells: a preliminary in vitro investigation

Schinifoline (SF), a 4-quinolinone derivative, was found in Zanthoxylum schinifolium for the first time. 4-Quinolinone moieties are thought to have cytotoxic activity and are often used as a tubulin polymerization inhibitors, heterogeneous enzyme inhibitors and antiplatelet agents. However, very little information respect to radiosensitization has focused on SF. This work aimed to investigate the radiosensitizing effect of SF on A549 cells. The cell viability results indicated cytotoxicity of SF on A549 cells, with IC₅₀ values of 33.7 ± 2.4, 21.9 ± 1.9 and 16.8 ± 2.2 μg/mL, respectively, after 6, 12, 24 h treatment with different concentrations, and the 10% or 20% IC₅₀ concentration during 12 h was applied in later experiments. The results of cell proliferative inhibition and clonogenic assay showed that SF enhanced the radiosensitivity of A549 cells when applied before ⁶⁰Co γ-irradiation and this effect was mainly time and concentration dependent. The flow cytometric data indicated that SF treatment before the irradiation increased the G₂/M phase, thus improving the radiosensitivity of A549, leading to cell apoptosis. This paper is the first study that describes the in vitro radiosensitising, cell cycle and apoptotic-inducing effects of schinifoline.

Drug resistance to molecular targeted therapy and its consequences for treatment decisions in non-small-cell lung cancer

Our ability to detect and directly target the oncogenic alterations responsible for tumor proliferation has contributed significantly to the management of lung cancer in the last decade. The therapeutic efficacy of molecularly targeted therapy is, however, mainly limited to patients harboring certain genetic mutations and is generally short-lived. Herein, we review primary and secondary drug resistance using the most well-studied of the molecularly targeted agents, the tyrosine kinase inhibitors targeting the epidermal growth factor (EGF) receptor, and the anaplastic lymphoma kinase (ALK) rearrangement, the current limitations of targeted therapies and their consequences on the management of patients with lung cancer.

MiR-21 suppresses the anticancer activities of curcumin by targeting PTEN gene in human non-small cell lung cancer A549 cells

PURPOSE

Curcumin, a natural phytochemical, exhibits potent anticancer activities. Here, we sought to determine the molecular mechanisms underlying the cytotoxic effects of curcumin against human non-small cell lung cancer (NSCLC) cells.

METHODS

MTT assay and annexin-V/PI staining were used to analyze the effects of curcumin on the proliferation and apoptosis of A549 cells. The expression of microRNA-21 in curcumin-treated A549 cells was measured by quantitative real-time polymerase chain reaction assay. The protein level of phosphatase and tensin homolog (PTEN), a putative target of microRNA-21, was determined by Western blot analysis. Transfection of A549 cells with microRNA-21 mimic or PTEN small interfering RNA was performed to modulate the expression of microRNA-21 and PTEN under the treatment of curcumin.

RESULTS

Curcumin at 20-40 μM inhibited cell proliferation and induced apoptosis in A549 cells. Curcumin treatment produced a dose-dependent and significant (P < 0.05) suppression of microRNA-21 expression, compared to untreated A549 cells. Moreover, the protein level of PTEN, a putative target of microRNA-21, was significantly elevated in curcumin-treated A549 cells, as determined by Western blot analysis. Transfection of A549 cells with microRNA-21 mimic or PTEN small interfering RNA significantly (P < 0.05) reversed the growth suppression and apoptosis induction by curcumin, compared to corresponding controls.

CONCLUSIONS

Our data suggest a novel molecular mechanism in which inhibition of microRNA-21 and upregulation of PTEN mediate the anticancer activities of curcumin in NSCLC cells. Suppression of microRNA-21 may thus have therapeutic benefits against this malignancy.

MiR-200c increases the radiosensitivity of non-small-cell lung cancer cell line A549 by targeting VEGF-VEGFR2 pathway

MicroRNAs (miRNAs) have been demonstrated to participate in many important cellular processes including radiosensitization. VEGF family, an important regulator of angiogenesis, also plays a crucial role in the regulation of cancer cell radiosensitivity. VEGFR2 mediates the major growth and permeability actions of VEGF in a paracrine/autocrine manner. MiR-200c, at the nexus of epithelial-mesenchymal transition (EMT), is predicted to target VEGFR2. The purpose of this study is to test the hypothesis that regulation of VEGFR2 pathway by miR-200c could modulate the radiosensitivity of cancer cells. Bioinformatic analysis, luciferase reporter assays and biochemical assays were carried out to validate VEGFR2 as a direct target of miR-200c. The radiosensitizing effects of miR-200c on A549 cells were determined by clonogenic assays. The downstream regulating mechanism of miR-200c was explored with western blotting assays, FCM, tube formation assays and migration assays. We identified VEGFR2 as a novel target of miR-200c. The ectopic miR-200c increased the radiosensitivity of A549 while miR-200c down-regulation decreased it. Besides, we proved that miR-200c radiosensitized A549 cells by targeting VEGF-VEGFR2 pathway specifically, thus leading to inhibition of its downstream pro-survival signaling transduction and angiogenesis, and serves as a potential target for radiosensitizition research.