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Radioresistance is one of the main reasons for the failure of radiotherapy in lung cancer. The present study was conducted to identify the role of miR-511 in suppressing the growth of radioresistant lung adenocarcinoma cells. First, a radioresistant A549/R cell line was generated after prolonged exposure to X-rays for 68 Gy (2 Gy/day, 5 days/week) and the radioresistance was confirmed by wound healing assay. Next, oncogenic TRIB2 was found to be upregulated in the radioresistant A549/R cells when compared to that of the control A549 cells as determined by western blot analysis. As the upstream miRNA, quantitative PCR showed that miR-511 expression was decreased in the radioresistant A549/R cells. Overexpression of miR-511 in miR-511-transfected A549/R cells inhibited cell growth and increased the number of apoptotic cells when compared with the control treatment. Flow cytometric analysis further demonstrated that the growth suppressive effect of miR-511 on A549/R cells was mediated by regulation of the cell cycle, most likely due to a block in the G1-S transition. Finally, our results showed that the expression of BAX was lower in the radioresistant A549/R cells when compared with that in the control A549 cells. After downregulation of TRIB2 by miR-511 treatment, BAX expression was obviously increased in the miR-511-transfected apoptotic A549/R cells when compared to that in the NC-treated or control cultures. In summary, our results revealed that miR-511 regulates the growth of radioresistant A549/R cells by increasing BAX expression through TRIB2, which suggests that miR-511 may be a potential therapeutic molecule for the treatment of radioresistant lung adenocarcinoma.

To explore the mechanism of apoptosis induced by cisplatin, the expression of microRNAs (miRNAs) and regulating genes in K562 cells was analyzed using reverse transcription PCR, quantitative real-time PCR and enzyme-linked immunosorbent assays. Our results showed that miR-16, miR-34a-c, miR-17-5p and miR-125 were up-regulated, and their associated oncogenes (BCL2, E2F1 and E2F3, respectively) were down-regulated after cisplatin treatment. We also showed that miR-106 and miR-150 were down-regulated while their target genes (RB1 and P53, respectively) were up-regulated after cisplatin treatment. Moreover, miR-16, miR-34a-c and miR-17-5p proved to be upstream factors, regulating the expression of BCL2, E2F1 and E2F3, respectively. The oncogene E2F3 was down-regulated when RB1 expression was increased after treatment with antisense oligonucleotides (ASO). Similarly, BCL2 and E2F3 were down-regulated when P53 expression was elevated by ASO treatment. The study demonstrated that cisplatin induces K562 cells to apoptosis by reducing miR-106 which up-regulates RB1 or by inhibiting miR-150 which increases P53 expression.

MicroRNAs (miRNAs) have a profound impact on cell processes, including proliferation, apoptosis, and stress responses. We aimed to explore the role of antisense oligonucleotide (ASO) to induce proliferation or apoptosis of A549 cancer cells by inhibiting the expression of miRNAs. After A549/HBE/293T cells were treated with ASO, cells proliferation/apoptosis, and their relevant oncogenes/tumor suppressor genes were detected by light and electron microscopy, real-time PCR, enzyme-linked immunosorbent assay, etc. The results showed that ASO could inhibit the expression of miRNAs effectively. miR-16, miR-17, miR-34a-c, and miR-125 served as tumor suppressor miRNAs, while miR-20, miR-106, and miR-150 acted as oncogenic miRNAs. Our results also indicated that miR-16/34a-c, miR-17-5p, miR-125, miR-106, and miR-150 were the upstream factors, which could regulate the expression of BCL-2, E2F1, E2F3, RB1, and P53, respectively. After A549 cells treated with ASO for 24 h and different concentrations of anti-cancer drug (cisplatin or demethylcantharidin) were added into culture medium, the results indicated the percentage of alive cells in group treated with both ASO-106 (or ASO-150) and anti-cancer drug was lower than that in group treated with ASO, or anti-cancer drug, or both ASO-16 (or ASO-34a) and anti-cancer drug. In conclusion, ASO (specific to oncogenic miRNAs) could induce A549 cells apoptosis by inhibiting oncogenic miRNAs, and could increase chemotherapy sensitivity of A549 cells to anti-cancer drug, which holds great promise to lung cancer therapy.

Background: The present study aimed to investigate the function of miR‐3529‐3p in lung adenocarcinoma and MnO2‐SiO2‐APTES (MSA) as a promising multifunctional delivery agent for lung adenocarcinoma therapy. Methods: Expression levels of miR‐3529‐3p were evaluated in lung carcinoma cells and tissues by qRT‐PCR. The effects of miR‐3529‐3p on apoptosis, proliferation, metastasis and neovascularization were assessed by CCK‐8, FACS, transwell and wound healing assays, tube formation and xenografts experiments. Luciferase reporter assays, western blot, qRT‐PCR and mitochondrial complex assay were used to determine the targeting relationship between miR‐3529‐3p and hypoxia‐inducible gene domain family member 1A (HIGD1A). MSA was fabricated using MnO2 nanoflowers, and its heating curves, temperature curves, IC50, and delivery efficiency were examined. The hypoxia and reactive oxygen species (ROS) production was investigated by nitro reductase probing, DCFH‐DA staining and FACS. Results: MiR‐3529‐3p expression was reduced in lung carcinoma tissues and cells. Transfection of miR‐3529‐3p could promote apoptosis and suppress cell proliferation, migration and angiogenesis. As a target of miR‐3529‐3p, HIGD1A expression was downregulated, through which miR‐3529‐3p could disrupt the activities of complexes III and IV of the respiratory chain. The multifunctional nanoparticle MSA could not only efficiently deliver miR‐3529‐3p into cells, but also enhance the antitumor function of miR‐3529‐3p. The underlying mechanism may be that MSA alleviates hypoxia and has synergistic effects in cellular ROS promotion with miR‐3529‐3p. Conclusions: Our results establish the antioncogenic role of miR‐3529‐3p, and demonstrate that miR‐3529‐3p delivered by MSA has enhanced tumor suppressive effects, probably through elevating ROS production and thermogenesis. [ABSTRACT FROM AUTHOR]

Solanine is an alkaloid and is the main extract of the traditional Chinese herb, Solanum nigrum Linn. It has been reported that Solanine has anti-inflammatory and antitumor properties. The present study aimed to investigate the antitumor effect of Solanine in Jurkat cells and demonstrate the molecular mechanism of antitumor activity of Solanine. A Cell Counting Kit-8 assay demonstrated that Solanine inhibited the proliferation of Jurkat cells in a dose-and time-dependent manner. Cell apoptosis was measured by flow cytometry. Flow cytometry revealed that Solanine induced apoptosis in a dose-dependent manner in Jurkat cells. Reverse transcription-quantitative polymerase chain reaction demonstrated that Solanine modulated the mRNA levels of B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax). Additionally, Bcl-2 and Bax expression was measured using western blot analysis. Western blot analysis revealed a significant increase in the expression of Bax and decrease in the expression of Bcl-2. Solanine increased the chemosensitivity of Jurkat cells to Adriamycin. In summary, the present results indicated that the antitumor activity of Solanine was associated with inhibition of cell proliferation, induction of apoptosis and increasing cytotoxicity of Adriamycin. Therefore, Solanine may have potential as a novel agent for the treatment of acute lymphocytic leukemia. [ABSTRACT FROM AUTHOR]

Cumulative evidence has indicated that celastrol may suppress cancer growth; however, the underlying mechanism requires further investigation. In the present study, A549 cells were treated with various concentrations of celastrol. Lung cancer cell proliferation was evaluated using an MTT assay and observed under a microscope. Cell apoptosis was detected by Annexin V fluorescein isothiocyanate/propidium iodide double-labeled flow cytometry. The results demonstrated that celastrol suppressed proliferation and induced apoptosis in a dose-independent manner. Celastrol may also decrease the phosphorylation levels of signal transducer and activator of transcription 3 (STAT3) and the B cell lymphoma-2 (Bcl-2)/Bcl-2 associated C protein (Bax) ratio. As microRNA (miR-24 and miR-181b) were predicated to target STAT3, STAT3 activation was inhibited in miR-24-or miR-181b-treated A549 cells compared with the control treatment. The ratio of Bcl-2/Bax was further reduced in miR-24 or miR-181b-treated A549 cells. The results were further confirmed by detecting in another lung adenocarcinoma cell line, LTEP-a-2. In summary, the results of the present study demonstrated that celastrol treatment suppressed the proliferation and induced apoptosis by regulating the expression levels of miR-24 and miR-181b. [ABSTRACT FROM AUTHOR]