Background: Although gemcitabine-based chemotherapy has been established as a core multimodal therapy for non-small cell lung cancer (NSCLC) treatment, its clinical efficacy remains limited by the development of acquired resistance following tumor metastasis and relapse. In this study, we investigated how gemcitabine-resistant (GR) cells contribute to the development of NSCLC tumor malignancy via exosome-mediated transfer of microRNAs. Methods: We first studied the mechanism of exosome internalization via PKH-67 staining and an immunofluorescence assay, then confirmed our finding by transmission electron microscopy and western blot analysis. Candidate miRNAs were identified through microarray analysis. Thereafter, RT-PCR, MTS, Transwell and soft agar assays were performed to assess the role of exosomic miR-222-3p in vitro. A 3’ untranslated region reporter assay was applied to identify the target of miR-222-3p. A lung metastasis mouse model was constructed to evaluate tumor growth and metastasis in vivo. Finally, clinical samples were used for correlation analysis between exosomic miR-222-3p levels and patients’ response to gemcitabine. Results: A549-GR–derived exosomes were internalized by receipt cells via caveolin- and lipid raft-dependent endocytosis, which allowed the transfer of miR-222-3p. Exosomic miR-222-3p enhanced the proliferation, gemcitabine resistance, migration, invasion, and anti-anoikis of parental sensitive cells by directly targeting the promoter of SOCS3. In addition, a higher level of exosomic miR-222-3p in sera usually predicted worse prognosis in NSCLC patients. Conclusion: Our data demonstrate that exosomic-miR-222-3p functions as a principal regulator of gemcitabine resistance and malignant characteristics by targeting SOCS3. The exosomic miR-222-3p level in sera may be a potential prognostic biomarker for predicting gemcitabine sensitivity in NSCLC patients.

Ovarian cancer (OVCa) stem cells are associated with tumor growth, metastasis, and recurrence, which are driving forces behind a majority of the OVCa-related mortality. This subpopulation of cancer cells are characterized by uncontrolled proliferation, high invasiveness, and resistance against the current platinum-based therapy. Thus, targeting OVCa cancer stem cells has been focused in recent therapeutic development. Isolation and purification of cancer stem cells are, however, challenging for the lack of sensitive and specific markers. In this study, we demonstrated that miR-551b was upregulated in OVCa stem cells, by using a quantitative PCR array, correlating with the pathological grades of this malignancy. In vitro experiments indicated that miR-551b promoted the proliferation, invasion, and chemoresistance of OVCa cells and cancer stem cells. Further analysis suggested that miR-551b functioned through the suppression of Foxo3 and TRIM31, two important tumor suppressors. In support of this, our in vivo experiments using mouse xenograft models showed that inhibiting miR-551b significantly increased the susceptibility of OVCa cells to cisplatin and prolonged the survival of the host mice. In conclusion, our study suggested miR-551b as a potential biomarker for OVCa stem cells and explored its functional mechanism, providing a potential therapeutic target for future drug development.

Background: Radiation exerts direct antitumor effects and is widely used in clinics, but the efficacy is severely compromised by tumor resistance. Therefore uncovering the mechanism of radioresistance might promote the development of new strategies to overcome radioresistance by manipulating activity of the key molecules. Methods: Immunohistochemistry were used to find whether mTOR were over-activated in radioresistant patients’ biopsies. Then Western blot, real-time PCR and transfection were used to find whether radiotherapy regulates the expression and activity of mTOR by modulating its targeting microRNA in human pancreatic cancer cell lines PANC-1, Capan-2 and BxPC-3. Finally efficacy of radiation combined with mTOR dual inhibitor AZD8055 was assessed in vitro and in vivo. Results: Ionizing radiation promoted mTOR expression and activation in pancreatic cancer cells through reducing miR-99b expression, which negatively regulated mTOR. Novel mTOR inhibitor, AZD8055 (10 nM, 100 nM, 500 nM) synergistically promoted radiation (0–10 Gy) induced cell growth inhibition and apoptosis. In human pancreatic cancer xenografts, fractionated radiation combined with AZD8055 treatment further increased the anti-tumor effect, the tumor volume was shrinked to 278 mm³ after combination treatment for 3 weeks compared with single radiation (678 mm³) or AZD8055 (708 mm³) treatment (P < 0.01). Conclusions: Our data provide a rationale for overcoming radio-resistance by combined with mTOR inhibitor AZD8055 in pancreatic cancer therapy.

MicroRNAs (miRNAs) are a class of small, noncoding RNAs that act as key regulators in various physiological and pathological processes. However, the regulatory mechanisms for miRNAs in colorectal cancer remain largely unknown. Here, we found that miR-103 is up-regulated in colorectal cancer and its overexpression is closely associated with tumor proliferation and migration. In addition, repressing the expression of miR-103 apparently inhibits colorectal cancer cell proliferation and migration in vitro and HCT-116 xenograft tumor growth in vivo. Subsequent software analysis and dual-luciferase reporter assay identified two tumor suppressor genes DICER and PTEN as direct targets of miR-103, and up-regulation of DICER and PTEN obtained similar results to that occurred in the silencing of miR-103. In addition, restoration of DICER and PTEN can inhibit miR-103-induced colorectal cancer cell proliferation and migration. Our data collectively demonstrate that miR-103 is an oncogene miRNA that promotes colorectal cancer proliferation and migration through down-regulation of the tumor suppressor genes DICER and PTEN. Thus, miR-103 may represent a new potential diagnostic and therapeutic target for colorectal cancer treatment.

Hepatocellular carcinoma (HCC) is the most common subtype of liver malignancy, and it is characterized by poor prognosis because of cancer stem cell (CSC)-mediated high postsurgical recurrence rates. Thus, targeting CSCs, or HCC cells with CSC-like properties, is an effective strategy for HCC therapy. Here, using long noncoding RNA (lncRNA) microarray analysis, we identified a novel lncRNA termed lncCAMTA1 that is increased in both liver CSCs and HCC. High lncCAMTA1 expression in HCC indicates poor clinical outcome. In vitro and in vivo functional experiments showed that overexpression of lncCAMTA1 promotes HCC cell proliferation, CSC-like properties, and tumorigenesis. Conversely, depletion of lncCAMTA1 inhibits HCC cell proliferation, CSC-like properties, and tumorigenesis. Mechanistically, we demonstrated that lncCAMTA1 physically associates with the calmodulin binding transcription activator 1 (CAMTA1) promoter, induces a repressive chromatin structure, and inhibits CAMTA1 transcription. Furthermore, CAMTA1 is required for the effects of lncCAMTA1 on HCC cell proliferation and CSC-like properties, and the expression of lncCAMTA1 and CAMTA1 is significantly negatively correlated in HCC tissues. Collectively, our study revealed the important roles and underlying molecular mechanisms of lncCAMTA1 on HCC, and suggested that lncCAMTA1 could be an effective prognostic factor and a potential therapeutic target for HCC.

Background: Luteolin (LUT) is a flavonoid found in vegetables and fruits that has diverse functions. Doxorubicin (DOX) is an anthracycline antibiotic that is frequently used for the treatment of various cancers. Unfortunately, the clinical efficacy of DOX is limited by its dose-related cardiotoxicity. In this study, we aimed to investigate the potential mechanism through which LUT attenuates cardiotoxicity in vivo. Methods: We evaluated the body weight, heart weight, electrocardiogram, and pathological changes before and after administration of LUT. Moreover, the effects of LUT (50 mg/kg in the low dose group, 100 mg/kg in the high dose group) on biochemical parameters (brain natriuretic peptide, creatine kinase MB, cardiac troponin T, and dehydrogenation of lactate enzyme) and oxidative stress parameters (malondialdehyde and superoxide dismutase) were studied in the sera of cardiotoxicity model rats. We also identified the apoptotic mediators whose expression was induced by LUT by quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) evaluation. In addition, we used network analysis to predict DOX-induced cardiotoxicity and protection afforded by LUT. Western blotting was used to detect the expression of associated proteins. Results: LUT significantly improved DOX-induced cardiotoxicity in a dose-dependent fashion. LUT ameliorated DOX-induced weight loss and heart weight changes, as well as changes in biochemical parameters and oxidative stress parameters in heart injury model rats. LUT’s protective effect was observed via regulation of the apoptotic markers Bcl-2, Bax, and caspase-3 mRNA and protein expression levels. Network analysis showed that the AKT/Bcl-2 signalling pathway was activated; specifically, the PH domain leucine-rich repeats protein phosphatase 1 (phlpp1) was involved in the AKT/Bcl-2 signal pathway. LUT inhibited the activity of phlpp1 leading to positive regulation of the AKT/Bcl-2 pathway, which attenuated doxorubicin-induced cardiotoxicity. Conclusions: These results demonstrate that LUT exerted protective effects against DOX-induced cardiotoxicity in vivo by alleviating oxidative stress, suppressing phlpp1 activity, and activating the AKT/Bcl-2 signalling pathway.