Cyclometalated ruthenium complexes overcome cisplatin resistance through PI3K/mTOR/Nrf2 signaling pathway.

Currently, cisplatin resistance remains a primary clinical obstacle in the successful treatment of non-small cell lung cancer. Here, we designed, synthesized, and characterized two novel cyclometalated Ru(II) complexes, [Ru(bpy)2(1-Ph-7-OCH3-IQ)] (PF6) (bpy = 2,2'-bipyridine, IQ = isoquinoline, RuIQ7)and [Ru(bpy)2(1-Ph-6,7-(OCH3)2-IQ)] (PF6) (RuIQ8). As experimental controls, we prepared complex [Ru(bpy)2(1-Ph-IQ)](PF6) (RuIQ6) lacking a methoxy group in the main ligand. Significantly, complexes RuIQ6-8 displayed higher in vitro cytotoxicity when compared to ligands, precursor cis-[Ru(bpy)2Cl2], and clinical cisplatin. Mechanistic investigations revealed that RuIQ6-8 could inhibit cell proliferation by downregulating the phosphorylation levels of Akt and mTOR proteins, consequently affecting the rapid growth of human lung adenocarcinoma cisplatin-resistant cells A549/DDP. Moreover, the results from qRT-PCR demonstrated that these complexes could directly suppress the transcription of the NF-E2-related factor 2 gene, leading to the inhibition of downstream multidrug resistance-associated protein 1 expression and effectively overcoming cisplatin resistance. Furthermore, the relationship between the chemical structures of these three complexes and their anticancer activity, ability to induce cell apoptosis, and their efficacy in overcoming cisplatin resistance has been thoroughly examined and discussed. Notably, the toxicity test conducted on zebrafish embryos indicated that the three Ru-IQ complexes displayed favorable safety profiles. Consequently, the potential of these developed compounds as innovative therapeutic agents for the efficient and low-toxic treatment of NSCLC appears highly promising.

Antitumor activity and mechanism of cucurbitacin B in A549/DDP cells.

Cucurbitacin B (CuB) is a class of tetracyclic triterpenoids isolated from Cucurbitaceae with a wide range of anti-inflammatory and anti-tumor activities, mainly used in hepatitis and hepatocellular carcinoma, while there is relatively little research and application of this drug for lung cancer. In this study, CuB was administered on A549/DDP cells to observe how it affected the cells and their mechanism of action. CuB demonstrated good anti-tumor activity against A549/DDP cells in a dose-dependent manner and caused changes in the hedgehog (Hh) pathway. The results showed that CuB greatly inhibits the proliferation and the invasion of A549/DDP cells, and promoted apoptosis of A549/DDP cells. Meanwhile, it changed the expression of p53-related genes at the RNA and protein level. In conclusion, this experiment provides a theoretical basis for new applications of CuB and new thoughts on the mechanism of its anti-tumor activity, and provides a direction for deep research.

Asiatic acid re-sensitizes multidrug-resistant A549/DDP cells to cisplatin by down regulating long non-coding RNA metastasis associated lung adenocarcinoma transcript 1/ß-catenin signaling.

Drug resistance becomes a challenge in the therapeutic management of non-small cell lung cancer (NSCLC). According to our former research, asiatic acid (AA) re-sensitized A549/DDP cells to cisplatin (DDP) through decreasing multidrug resistance protein 1 (MDR1) expression level. However, the relevant underlying mechanisms are still unclear. Long non-coding RNA (lncRNA) MALAT1 shows close association with chemo-resistance. As reported in this research, AA increased apoptosis rate, down regulated the expression of MALAT1, p300, ß-catenin, and MDR1, up regulated the expression of miR-1297, and decreased ß-catenin nuclear translocation in A549/DDP cells. MALAT1 knockdown expression abolished the drug resistance of A549/DDP cells and increased cell apoptosis. MALAT1 could potentially produce interactions with miR-1297, which targeted to degradation of p300. In addition, p300 overexpression effectively rescued the effects of MALAT1 knockdown expression on A549/DDP cells and activate the expression of ß-catenin/MDR1 signaling, and these could be effectively blocked by AA treatment. Conclusively, AA could re-sensitize A549/DDP cells to DDP through down-regulating MALAT1/miR-1297/p300/ß-catenin signaling.

[Down-regulation of MDR1 gene expression by CRISPRi to enhance the sensitivity of lung adenocarcinoma A549/DDP cells to cisplatin].

OBJECTIVE: To investigate the effects of down-regulating MDR1 gene expression by CRISPRi on enhancing the sensitivity of lung adenocarcinoma A549/DDP cells to cisplatin. METHODS: The potential CRISPRi interference sites on the MDR1 gene promoter were predicted by bioinformatics software, and the interference fragments were designed and constructed. The mRNA and protein expression levels of MDR1 gene in each group of cells were detected by qRT-PCR and Western blot methods, and the recombinant vectors with high interference efficiency were screened. Human lung cancer A549/DDP cells were divided into three groups: A549/DDP, Scrambed and sgRNA-MDR1-1, with three multiple holes in each group. After each vector was transfected into the cells for 48 h, the efflux of cells in each group was detected by flow cytometry, the IC50 value of cells in each group was detected by MTT method, and the cell morphology of cells treated with cisplatin was observed under laser confocal microscope. RESULTS: After sequencing and comparison, two kinds of CRISPRi recombinant vectors interfering with MDR1 gene transcription were constructed successfully. After transfection of A549/DDP cells, the mRNA and protein levels of MDR1 gene in all transfection groups were decreased significantly (P＜ 0.01). Among them, the interference efficiency of sgRNA-MDR1-1 was the highest, and the interference efficiency of mRNA and protein was 60% and 51%, respectively. After transfection of sgRNA-MDR1-1 vector, compared with the control group, the efflux ability of cells was decreased (P＜0.01), the IC50 value of cells to cisplatin was decreased significantly (P＜0.01), and the intracellular chromatin gathered and marginalized, and apoptotic bodies appeared. CONCLUSION: CRISPRi interference with MDR1 gene in drug-resistant A549/DDP cells can significantly enhance the sensitivity to cisplatin.

Honokiol combined with curcumin sensitizes multidrug-resistant human lung adenocarcinoma A549/DDP cells to cisplatin.

The aim of the present study was to discuss the effects and underlying mechanisms of honokiol (HNK) and/or curcumin (CUR) in sensitization of multidrug-resistant human lung adenocarcinoma A549/DDP cells to cisplatin (DDP). An MTS assay was performed to detect the cytotoxicity of HNK, CUR and DDP in A549 and A549/DDP cells and compare their sensitivity. The A549/DDP cells were then divided into 8 groups: Control, HNK, CUR, DDP, HNK + CUR, HNK + DDP, CUR + DDP and HNK + CUR + DDP. Cell proliferation was measured by MTS assay and colony formation assay, cell apoptosis was detected by flow cytometry, cell invasion was evaluated by Transwell assay and cell migration was determined by a wound healing assay. In order to investigate the possible mechanisms, P-glycoprotein (P-gp) protein expression was measured by western blotting and immunofluorescence assays. The mRNA expression levels of AKT, Erk1/2, cyclin-dependent kinase inhibitor 1 (P21), caspase 3, cleaved caspase 3, caspase 9, cleaved caspase 9, poly (ADP-ribose) polymerase (PARP), cleaved PARP, matrix metalloproteinase (MMP)-2 and MMP-9 were examined by reverse transcription-quantitative (RT-q) PCR assay, and the protein expression levels of phosphorylated (p)-AKT, p-Erk1/2, P21, caspase 3, cleaved caspase 3, caspase 9, cleaved caspase 9, PARP, cleaved PARP, MMP-2 and MMP-9 proteins expression by western blot assay. The MTS assay demonstrated that HNK (5 µg/ml), CUR (10 µg/ml) and DDP (5 µg/ml) had no obvious toxicity to A549/DDP cells, and HNK, CUR and DDP were more sensitive in A549 cells compared with A549/DDP cells. The optimal concentrations of HNK (5 µg/ml), CUR (10 µg/ml) and DDP (5 µg/ml) were chosen to carry out the further experiments. Compared with the control group, no significant change was observed in cell proliferation, apoptosis, migration, invasion and related mRNA and protein expression in HNK, CUR, DDP and HNK + CUR groups. The cell proliferation rate in the HNK + DDP and CUR + DDP groups was significantly suppressed with cell apoptosis significantly increased, respectively. The invasion cell number and wound healing rate of HNK + DDP and CUR + DDP groups were significantly depressed compared with the control group, respectively. Immunofluorescence demonstrated that the nuclear volume of P-gp in HNK + DDP and CUR + DDP groups were significantly downregulated compared with the control group, respectively. The RT-qPCR assay demonstrated that the AKT, Erk1/2 and P21 mRNA expression levels were significantly decreased and cleaved caspase 3, cleaved caspase 9 and cleaved PARP were increased in HNK + DDP and CUR + DDP groups compared with the control group. The western blotting results were consistent with the RT-qPCR results. NK + CUR + DDP had improved effects on A549/DDP compared with HNK + DDP or CUR + DDP group, respectively. HNK and/or CUR could improve the sensitivity of DDP to A549/DDP cell by the regulation of P-gp, inducing apoptosis, and inhibiting migration and invasion via AKT/ERK signal pathway in an in vitro study.

RASSF1A Enhances Chemosensitivity of NSCLC Cells Through Activating Autophagy by Regulating MAP1S to Inactivate Keap1-Nrf2 Pathway.

OBJECTIVE: Cisplatin (DDP) is an effective first-line therapy for non-small cell lung cancer (NSCLC) treatment; however, it can cause resistance and thus pose an obstacle to the efficacy of chemotherapy in NSCLC. This study aims to detect the effect of RASSF1A on DDP resistance of NSCLC and the underlying mechanism. METHODS: The expression levels of RASSF1A and microtubule-associated protein 1S (MAP1S) were investigated by qRT-PCR and Western blot and their interaction was testified by co-immunoprecipitation (Co-IP) analysis. The IC50 value of DDP on A549 and A549/DDP cells (DDP-resistant cells) was measured. A549/DDP cells were transfected with pCDNA3.1-RASSF1A, pCDNA3.1-MAP1S, or si-RASSF1A, followed by treated with DDP. Cell counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EDU) were employed to measure cell survival rate. Western blot was applied to test the levels of autophagy-associated proteins p62, LC3II, and LC3I. Immunofluorescence staining was used to detect the green fluorescent protein (GFP)-LC3 puncta to evaluate the level of autophagy. Finally, a xenograft model in nude mice using A549/DDP cells was developed. RESULTS: RASSF1A and MAP1S were lowly expressed and positively correlated in NSCLC tissues. We observed that RASSF1A and MAP1S overexpression significantly enhanced DDP-induced effects in A549 and A549/DDP cells, including decreased cell viability, as well as increased autophagy levels. Besides, investigations into the mechanism between RASSF1A and MAP1S disclosed that RASSF1A could regulate MAP1S to inactivate the Keap1-Nrf2 pathway, thus activating autophagy to enhance chemosensitivity. Moreover, consistent results were confirmed in vivo experiments. CONCLUSION: RASSF1A increases chemosensitivity in NSCLC by facilitating autophagy via MAP1S-mediated Keap1-Nrf2 pathway.

Enhanced lysosomal function is critical for paclitaxel resistance in cancer cells: reversed by artesunate.

The mechanism underlying the resistance of cancer cells to chemotherapeutic drug varies with different cancer cells. Recent evidence shows that lysosomal function is associated with drug resistance of cancer cells. Artesunate, a derivative of artemisinin, displays broad antitumor activity and direct cytotoxicity on various tumor cells. Our previous study shows that artesunate increases autophagosome accumulation, while significantly decreases autolysosome number in cancer cells, suggesting that artesunate might impair the lysosomal function. In this study, we investigated the effects of artesunate on lysosomal function and its relationship with chemotherapeutic drug resistance in cancer cells. We found that the lysosomal function was significantly enhanced in two drug-resistant (A549/TAX and A549/DDP) cells. Furthermore, we showed that the enhanced lysosomal function by overexpression of transcription factor EB (TFEB) significantly increased MCF-7 cells resistance to doxorubicin (DOX), whereas the decreased lysosomal function by TFEB-knockdown or lysosome inhibitor chloroquine increased MCF-7 cells sensitivity to DOX. Treatment of A549/TAX cells with artesunate (2.5-50 µM) dose-dependently inhibited lysosomal function and the clearance of dysfunctional mitochondria, and induced cell apoptosis. Moreover, we demonstrated that artesunate exerted more potent inhibition on the resistant (A549/TAX and MCF-7/ADR) cells with higher activity of lysosomal function. Our results suggest that artesunate or other inhibitors of lysosomal function would be potential in the treatment of cancer cells with drug resistance caused by the enhanced lysosomal function.

Saikosaponin A Changes Drug Resistance of A549/DDP Cells Through Wnt/β-Catenin Pathway / 中国实验方剂学杂志

Objective:To investigate the effect and mechanism of saikosaponin A （SSA） on the reversal of cisplatin （DDP） resistance in human lung cancer cell line A549/DDP. Methods:The resistance of A549 and A549/DDP cells to DDP and the inhibitory effects of SSA against the proliferation of A549 and A549/DDP cells were detected using cell counting kit-8 （CCK-8）. The apoptosis rates of A549/DDP cells treated with SSA or DDP or SSA combined with DDP and the changes in reactive oxygen species （ROS） were determined by flow cytometry. The mRNA expression levels of C-myc， B-cell lymphoma 2 （Bcl-2） and cysteinyl aspartate-specific protease-3 （Caspase-3） were detected by real-time polymerase chain reaction （Real-time PCR）， followed by the determination of <italic>β</italic>-catenin transcriptional activity using the TopFish dual-luciferase reporter assay system and the measurement of <italic>β</italic>-catenin protein expression in A549/DDP cells by Western blot. Results:The results of CCK-8 assay showed that the DDP resistance of A549/DDP cells was 12.82 times that of A549 cells （<italic>P</italic><0.05）. SSA inhibited the viability of A549 cells with the half maximal inhibitory concentration （IC₅₀） being 34.9 μmol·L^-1， and also suppressed the viability of A549/DDP cells in a concentration-dependent manner. Since the inhibition rate of 20 μmol/L SSA against A549/DDP cells was less than 10%， the reversal concentration was set at 20 μmol/L. Flow cytometry revealed that compared with the control， DDP alone increased the apoptosis rate of A549/DDP cells （<italic>P</italic><0.05）， stimulated the accumulation of intracellular ROS （<italic>P</italic><0.05）， down-regulated the mRNA expression levels of C-myc and Bcl-2 in A549/DDP cells， up-regulated Caspase-3 mRNA expression， and reduced the transcriptional activity of <italic>β</italic>-catenin （<italic>P</italic><0.05）. Compared with the DDP group， the SSA+DDP group exhibited obviously increased apoptosis of A549/DDP cells， enhanced accumulation of intracellular ROS， down-regulated C-myc and Bcl-2 mRNA expression， up-regulated Caspase-3 mRNA expression （<italic>P</italic><0.05）， and weakened <italic>β</italic>-catenin transcription （<italic>P</italic><0.05）. DDP combined with SSA better decreased the <italic>β</italic>-catenin protein expression in contrast to that of control or DDP （<italic>P</italic><0.05）. Conclusions:SSA enhances the sensitivity of A549/DDP cells to DDP possibly by inhibiting the activation of Wnt/<italic>β</italic>-catenin pathway.

MiR-320a is associated with cisplatin resistance in lung adenocarcinoma and its clinical value in non-small cell lung cancer: A comprehensive analysis based on microarray data.

BACKGROUND: Currently, the main treatment for non-small cell lung cancer (NSCLC) is surgery and chemotherapy. Although major progress has been made in targeted treatment and immunotherapy, the survival rates for this disease are still low and associated with resistance to chemotherapy. Previous studies have shown that histone acetylation and microRNAs (miRNAs) might play an important role in chemotherapy resistance. The aim of this study was to identify candidate miRNAs related to cisplatin (DDP) resistance in lung adenocarcinoma. METHODS: We used 5-aza-2'-deoxycytidine and trichostatin A to reverse the drug resistance of A549/DDP cells in vitro, and miRNA expression profiling was performed by microarrays to identify candidate miRNAs. In addition, we investigated the correlations between miR-320a expression and clinical characteristics through data collected from Gene Expression Omnibus (GEO) microarrays, and The Cancer Genome Atlas (TCGA) to determine the clinical role of miR-320a in lung adenocarcinoma. Furthermore, we investigated the biological function of miR-320a. TargetScanHuman, PicTar2005 and miRanda v5.1. were used to predict the target genes of miR-320a; then, the function of these genes were suggested from the enrichment of GO categories items and KEGG analyses. RESULTS: Treatment with 5-Aza-dc significantly inhibited cellular proliferation, and increased apoptosis in the A549/DDP cells compared with the untreated cells. TSA did not reverse cisplatin resistance. MiR-320a was up-regulated during reversal of cisplatin resistance. The lung adenocarcinoma groups had a significantly lower level of miR-320a expression than the control groups. For the bioinformatics analyses, we found some target genes involved in cell cycle progression, tumor progression, the MAPK signaling pathway, and the ErbB signaling pathway. The promising target genes were highly enriched in various pathways in cancer. CONCLUSIONS: The current study confirmed miR-320a was up-regulated during the revering of cisplatin resistance. The results of bioinformatics analyses may present a new method for investigating the pathogenesis of lung adenocarcinoma.

A milbemycin compound isolated from Streptomyces Sp. FJS31-2 with cytotoxicity and reversal of cisplatin resistance activity in A549/DDP cells.

Streptomyces Sp FJS31-2 is a strain isolated from special habitat soils in the early stage of our laboratory for producing a new type of halogenated type II polyketide antibiotic with good anti-MRSA activity. In this experiment, a variety of chromatographic and spectroscopic methods was used to isolate and identify a milbemycin compound VM48130 from the ethyl acetate extract of the fermentation products. To investigate its bioactivity, Cell Counting Kit-8 (CCK-8) assay was used to test the cytotoxic activity of the compound against a variety of cancer cells (human liver cancer cell line MHCC97H and SK-Hep1, human nasopharyngeal carcinoma cell line CNE1, mouse melanoma cell line B16, human colon cancer cell line LOVO, human lung adenocarcinoma cell line A549) and normal cells (human bronchial epithelial cell line 16HBE, human normal liver cell line L02, human nasopharyngeal epithelial cell line NP69). The results showed that the compound had significant cytotoxic activity against the above cancer cells, and the IC50 values were 21.96 ± 1.45, 22.18 ± 0.55, 19.42 ± 0.71, 18.61 ± 1.68, 18.62 ± 0.67, 18.52 ± 0.64 µM, respectively. Furthermore, the CCK-8 method was used to evaluate the compound's reversal of cisplatin resistance in multidrug resistant cisplatin-resistant human lung adenocarcinoma (A549/DDP) cells. The results indicated that when the compound concentration was 0.5 µM, the reversal fold (RF) reached 6.25 and showed a dose-dependent effect. At 5 µM, the RF reached 8.35, which was approximately equivalent to the reversal effect of the positive drug verapamil at the same concentration. The expression of MDR1, MRP1, LRP, MAST1 resistance genes and the corresponding proteins were analyzed by quantitative RT-PCR and Western blot assay, and found that the compound could significantly down-regulate the expression of these genes and proteins. These results indicated that VM48130 had the potential of being a lead compound for the treatment or adjuvant treatment of cancer.

Effect of cryptotanshinone on ferroptosis-related gene expression in lung cancer cells / 中国药理学通报

Aim To investigate the effects of cryptotanshinone on cell viability Aim To investigate the effects of cryptotanshinone on cell viability and ferroptosis-related gene expression in A549 and A549/DDP cells, and to explore its possible mechanisms. Methods A549 and A549/DDP cells were treated with different concentrations of CTS. Cell viability was measured by CCK-8 assay. The mRNA levels of TFR1, DMT1, IREB2, HSPB1, VDAC2, VDAC3 and GPX4 were measured by qPCR, and the protein levels of TFR1 were measured by Western blot. Results The cell viability was down-regulated by CTS in A549 and A549/DDP cells, while the cisplatin-resistant A549/DDP cells were more susceptible to CTS. After CTS treatment, the mRNA levels of ferroptosis-related genes showed different degrees of change. The mRNA levels of HSPB1 and GPX4 increased in A 5 4 9 cells , of which the mRNA levels of IREB2, VDAC2 and VDAC3 were reduced and the mRNA levels of TFR1 and DMT1 exhibited no significant change. The mRNA levels of TFR1 and IREB2 increased in A549/DDP cells, while the mRNA levels of VDAC3 decreased, and the expression levels of DMT1, HSPB1, VDAC2 and GPX4 did not changesignificantly. Conclusions Cryptotanshinone may inhibit the proliferation of lung cancer A549 and A549/DDP cells, and affect the expression of ferroptosis-re-lated genes.

Inhibitor of DNA binding 3 reverses cisplatin resistance in human lung adenocarcinoma cells by regulating the PI3K/Akt pathway.

Inhibitor of DNA-binding 3 (ID3) is a helix-loop-helix transcription factor that is associated with cell proliferation, differentiation and drug resistance in human cancer, and with anticancer effects in certain types of cancer cells. The present study investigated whether and how ID3 was involved in multidrug resistance (MDR) in human cisplatin (DDP)-resistant A549/DDP lung adenocarcinoma cells. The underlying mechanism of action was investigated in vitro. Cell Counting Kit-8 (CCK-8) and flow cytometry assays demonstrated that overexpression of ID3 enhanced chemosensitivity and decreased drug efflux in A549/DDP cells. Reverse transcription-quantitative polymerase chain reaction revealed that the expression of anti-apoptotic gene B-cell lymphoma-2 was significantly downregulated in cells expressing exogenous ID3 (P<0.05). These results indicated that ID3 may synergize with DDP to increase apoptosis in A549/DDP cells. ID3 overexpression modulated the activity of phosphoinositide 3-kinase/RAC serine/threonine-protein kinase signaling and downregulated the expression of multi-drug resistance protein-1, indicating that ID3 expression can reverse multi-drug resistance in A549/DDP cells. Collectively, these results indicate that ID3 is a potential effective chemotherapeutic target for the treatment of human DDP-resistant A549 lung adenocarcinoma therapy.

Asiatic Acid (AA) Sensitizes Multidrug-Resistant Human Lung Adenocarcinoma A549/DDP Cells to Cisplatin (DDP) via Downregulation of P-Glycoprotein (MDR1) and Its Targets.

BACKGROUND/AIMS: P-glycoprotein (P-gp, i.e., MDR1) is associated with the phenotype of multidrug resistance (MDR) and causes chemotherapy failure in the management of cancers. Searching for effective MDR modulators and combining them with anticancer drugs is a promising strategy against MDR. Asiatic acid (AA), a natural triterpene isolated from the plant Centella asiatica, may have an antitumor activity. The present study assessed the reversing effect of AA on MDR and possible molecular mechanisms of AA action in MDR1-overexpressing cisplatin (DDP)-resistant lung cancer cells, A549/DDP. METHODS: Human lung adenocarcinoma A549/DDP cells were either exposed to different concentrations of AA or treated with DDP, and their viability was measured by the MTT assay. A Rhodamine 123 efflux assay, immunofluorescent staining, ATPase assay, reverse-transcription PCR (RT-PCR), and western blot analysis were conducted to elucidate the mechanisms of action of AA on MDR. RESULTS: Our results showed that AA significantly enhanced the cytotoxicity of DDP toward A549/DDP cells but not its parental A549 cells. Furthermore, AA strongly inhibited P-gp expression by blocking MDR1 gene transcription and increased the intracellular accumulation of the P-gp substrate Rhodamine 123 in A549/DDP cells. Nuclear factor (NF)-kB (p65) activity, IkB degradation, and NF-kB/p65 nuclear translocation were markedly inhibited by pretreatment with AA. Additionally, AA inhibited the MAPK-ERK pathway, as indicated by decreased phosphorylation of ERK1 and -2, AKT, p38, and JNK, thus resulting in reduced activity of the Y-box binding protein 1 (YB1) via blockage of its nuclear translocation. CONCLUSIONS: AA reversed P-gp-mediated MDR by inhibition of P-gp expression. This effect was likely related to downregulation of YB1, and this effect was mediated by the NF-kB and MAPK-ERK pathways. AA may be useful as an MDR reversal agent for combination therapy in clinical trials.

Inhibition of Glucose-6-Phosphate Dehydrogenase Reverses Cisplatin Resistance in Lung Cancer Cells via the Redox System.

The pentose phosphate pathway (PPP), which branches from glycolysis, is correlated with cancer cell proliferation, survival and senescence. In this study, differences in the metabolic profile of the PPP and the redox status of human lung carcinoma A549 cells and cisplatin-induced multidrug-resistant A549/DDP cells were analyzed and evaluated. The results showed that A549/DDP cells exhibited differential PPP-derived metabolic features and redox-related molecules. A549/DDP cells exhibited increased expression and enzymatic activity of PPP enzyme glucose-6-phosphate dehydrogenase (G6PD). Furthermore, as demonstrated by the apoptotic rate, cell viability, and colony formation, inhibition of G6PD by siRNA or an inhibitor sensitized A549/DDP cells to cisplatin. Additionally, inhibition of G6PD restored the cisplatin sensitivity of A549/DDP cells by influencing redox homeostasis. In conclusion, overcoming cisplatin resistance through inhibition of G6PD could improve the understanding of the mechanisms underlying cisplatin-induced resistance in human lung cancer and may provide insights into the therapeutic potential of this treatment to combat resistance.

Research on Reversal Effects in Cisplatin-resistant Human Lung Adenocarcinoma Cell Line A549/DDP by Standard Substances from Traditional Chinese Medicine / 世界科学技术-中医药现代化

Objective: To investigate the reversal effects in A549/DDP by standard substances (SS) from Traditional Chinese Medicine. Methods: Cell proliferation assays were performed to investigate the Resistant Index of A549/DDP and its tolerance to selected SS. The working concentrations of SS, IC5 calculated by nonlinear regressions, were applied as reversal doses to investigate the effects. Results: The resistant index of A549/DDP was 31.79. Tetramethylpyrazine and Matrine were well tolerated. Berberine hydrochloride, Dauricine, Oridomin exhibited dose-depend inhibitory effects on A549/DDP cell line. The working concentrations of them could effectively reverse the resistance of A549/DDP cell line to DDP. (P＜0.01) . Conclusion: The selected standard substances from Traditional Chinese Medicine were capable to reverse the resistance of A549/DDP cell line to DDP.

Effects of high-intensity focused ultrasound on cisplatin-resistant human lung adenocarcinoma in vitro and in vivo.

It is widely accepted that high-intensity focused ultrasound (HIFU) is a minimally invasive treatment option for different tumors, but its roles and the corresponding mechanism in cisplatin (DDP) chemoresistance in lung adenocarcinoma (LA) remain unclear. In this study, we investigated the response of DDP-resistant LA cells to HIFU and its underlying molecular mechanisms using molecular biology techniques. It was found that HIFU exposure inhibited the proliferation of DDP-resistant A549 (A549/DDP) cells through arresting cell cycle at the G1/G0 phase via the Cyclin-dependent pathway and promoting apoptosis in a Bcl-2-dependent manner. Furthermore, the results also showed that HIFU exposure could down-regulate the expressions of MDR1, MRP1, and LRP mRNAs, as well as P-gp, MRP1, and LRP proteins related to drug resistance in A549/DDP cells. In vivo experiments also demonstrated that HIFU could reduce the size and mass of subcutaneously transplanted tumors produced by A549/DDP cells through mediating Cyclin-dependent and Bcl-2-dependent pathways. These results suggested that HIFU treatment could inhibit the proliferation of DDP-resistant lung cancer cells and might be a novel therapeutic method for patients with DDP resistance.

[Effects of Buzhong Yiqi decoction on expression of Bad, NF-κB, caspase-9, Survivin, and mTOR in nude mice with A549/DDP transplantation tumors].

This study was aimed to explore the effects of Buzhong Yiqi decoction on the expression levels of Bad, NF-κB, caspase-9, Survivin, and mTOR in nude mice with A549/DDP transplantation tumors.Sixty BALB/C mice were randomly divided into blank control group, tumor-bearing control group, cisplatin group and Buzhong Yiqi decoction of high, medium and low doses+cisplatin groups (hereinafter referred to as the high,medium and low combined groups). A549/DDP cells (concentration of 5×106 cells/mL)were cultured and inoculated in various groups, then the tumor-forming situations were observed. Corresponding treatment was given in all groups. Fourteen days later, immunohistochemistry and Real-time PCR methods were used to detect the expression levels of Bad, NF-κB, caspase-9, Survivin, mTOR protein and mRNA in tumors.Results showed that Buzhong Yiqi decoction combined with cisplatin could reduce the volume of transplanted tumors, and there was significant difference between medium combined group and high combined group(P<0.05). As compared with the tumor-bearing control group, the expression levels of Bad, NF-κB, Survivin and mTOR were significantly reduced in medium and high combined groups(P<0.05); the protein and mRNA expression levels of caspase-9 were gradually increased in medium combined and high combined groups(P<0.05), with statistical difference with tumor-bearing control group(P<0.05). There were statistical difference in mRNA expression of Bad, NF-κB and caspase-9 between medium combined group, high combined group and cisplatin group, low-combined group, tumor-bearing control group(P<0.05), but there was no statistical difference between cisplatin group, low-combined group, and tumor-bearing control group. In addition, there was no statistical difference between medium combined group and high combined group in protein and mRNA expression levels of various factors. Experimental results showed that Buzhong Yiqi decoction combined with cisplatin can inhibit the growth of A549/DDP transplanted tumors, and the mechanism may be associated with regulating Bad, NF-κB, caspase-9, Survivin, and mTOR levels as well as promoting apoptosis.

Role of gambogic acid and NaI131 in A549/DDP cells.

Resistance to platinum in tumor tissue is a considerable barrier against effective lung cancer treatment. Radionuclide therapy is the primary adjuvant treatment, however, the toxic side effects limit its dosage in the clinical setting. Therefore, the present study aimed to determine whether an NaI131 radiosensitizer could help reduce the toxic side effects of radionuclide therapy. In vitro experiments were conducted to determine whether NaI131 can inhibit platinum resistance in A549/DDP cells, which are cisplatin-resistant non-small cell lung cancer cells, and whether gambogic acid (GA) is an effective NaI131 radiosensitizer. Cell proliferation following drug intervention was analyzed using MTT and isobolographic analysis. Apoptosis was assessed by flow cytometry. In addition, the mechanisms of drug intervention were analyzed by measuring the expression of P-glycoprotein (P-gP), B cell lymphoma 2 (Bcl-2), Bcl2-associated X protein (Bax) and P53 using western blot analysis and immunocytochemistry. According to isobolographic analysis, a low concentration of NaI131 combined with GA had a synergistic effect on the inhibition of A549/DDP cell proliferation, which was consistent with an increased rate of apoptosis. Furthermore, the overexpression of Bax, and the downregulation of P-gP, P53 and Bcl-2 observed demonstrated the potential mechanism(s) of NaI131 and GA intervention. NaI131 may induce apoptosis in A549/DDP cells by regulating apoptosis-related proteins. A low concentration combination of NaI131 and GA was able to significantly inhibit A549/DDP cell proliferation and induce cell apoptosis. Thus, the two drugs appear to have a synergistic effect on apoptosis of A549/DDP cells.

Correlation of long non-coding RNA H19 expression with cisplatin-resistance and clinical outcome in lung adenocarcinoma.

The acquired drug resistance would influence the efficacy of cisplatin-based chemotherapy in non-small-cell lung cancer. The present study aimed to investigate the correlation of long non-coding RNA (lncRNA) H19 with cisplatin-resistance and clinical outcome in lung adenocarcinoma. In our study, the expression of H19 in cisplatin-resistant A549/DDP cells was unregulated. Knockdown of H19 restored the response of A549/DDP cells to cisplatin. H19-mediated chemosensitivity enhancement was associated with metastasis, induction of G0/G1 cell-cycle arrest, cell proliferation, and increased apoptosis. Furthermore, lncRNA H19 expression was significantly related to TNM stage and metastasis (P = 0.012). Overexpression of H19 was negatively correlated with cisplatin-based chemotherapy response in patients. Patients with high H19 expression exhibited a significantly shorter median progression-free survival (PFS) [4.7 months] than the low-expression patients (6.3months) [P = 0.002]. In summary, H19-mediated regulation of cisplatin resistance in human lung adenocarcinoma cells is demonstrated for the first time. H19 could potentially serve as a molecular marker to predict the clinical outcomes of lung adenocarcinoma patients.

ERCC1-shRNA inhibits the proliferation and promotes the apoptosis of lung cancer A549/DDP cells / 医学研究生学报

Objective Studies show that the ERCC1 gene may be involved in secondary cisplatin resistance.This article aims to investigate the effects of shRNA targeting silencing excision repair cross-complementation group 1 (ERCC1-shRNA) on the proliferation and apoptosis of lung cancer A549/DDP cells treated with different concentrations of cisplatin.Methods Lung cancer A549/DDP cells were divided into a negative control, a blank control, an ERCC1-shRNA1, and an ERCC1-shRNA2 group.Human interfering RNA (RNAi) targeting the human ERCC1 gene was constructed and transfected into the A549/DDP cells using Lipofectamine 2000.The mRNA and protein expressions of ERCC1 in the A549/DDP cells were detected by real-time PCR and Western blot respectively, the proliferation-inhibition rate was assessed by MTT, and their cell cycle and apoptosis were determined by flow cytometry.Results ERCC1-shRNA was successfully constructed and transfected into the A549/DDP cells.Both the mRNA and protein expressions of ERCC1 were significantly lower in the ERCC1-shRNA1 (0.20±0.04 and 0.24±0.10) and ERCC1-shRNA2 (0.47±0.28 and 0.37±0.11) than in the negative control (0.96±0.12 and 1.32±0.13) and blank control groups (0.84±0.07 and 1.45±0.23) (P<0.01).Compared with the negative and blank control groups, the ERCC1-shRNA1 group showed a significantly decreased IC50 value (16.71±2.33 and 16.69±1.69 vs 7.78±0.54, P<0.01) and an increased proportion of G0/G1 phase cells ([72.87±3.23] and [71.75±4.56] vs [82.99±4.23]%, P<0.05), with the cell cycle arrested in the G0/G1 phase.The apoptosis rate of the cells in the ERCC1-shRNA1 group was remarkably lower after treated with cisplatin at the concentrations of 6.25 and 12.5 μg/mL than at 0 μg/mL ([8.17±0.65] and [11.91±1.41] vs [29.97±3.14]%, P<0.05).Conclusion ERCC1-shRNA can inhibit the proliferation and enhance the apoptosis of A549/DDP cells by silencing the expression of the ERCC1 gene.