miR-196b-5p-mediated downregulation of TSPAN12 and GATA6 promotes tumor progression in non-small cell lung cancer.

Lung cancer is the leading cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) accounts for over 80% of lung cancer cases. The RNA binding protein, QKI, belongs to the STAR family and plays tumor-suppressive functions in NSCLC. QKI-5 is a major isoform of QKIs and is predominantly expressed in NSCLC. However, the underlying mechanisms of QKI-5 in NSCLC progression remain unclear. We found that QKI-5 regulated microRNA (miRNA), miR-196b-5p, and its expression was significantly up-regulated in NSCLC tissues. Up-regulated miR-196b-5p promotes lung cancer cell migration, proliferation, and cell cycle through directly targeting the tumor suppressors, GATA6 and TSPAN12. Both GATA6 and TSPAN12 expressions were down-regulated in NSCLC patient tissue samples and were negatively correlated with miR-196b-5p expression. Mouse xenograft models demonstrated that miR-196b-5p functions as a potent onco-miRNA, whereas TSPAN12 functions as a tumor suppressor in NSCLC in vivo. QKI-5 bound to miR-196b-5p and influenced its stability, resulting in up-regulated miR-196b-5p expression in NSCLC. Further analysis showed that hypomethylation in the promoter region enhanced miR-196b-5p expression in NSCLC. Our findings indicate that QKI-5 may exhibit novel anticancer mechanisms by regulating miRNA in NSCLC, and targeting the QKI5∼miR-196b-5p∼GATA6/TSPAN12 pathway may enable effectively treating some NSCLCs.

Gracillin shows potent efficacy against colorectal cancer through inhibiting the STAT3 pathway.

Colorectal cancer (CRC) accounts for about 10% of all annually diagnosed cancers and cancer-related deaths worldwide. STAT3 plays a vital role in the occurrence and development of tumours. Gracillin has shown a significant antitumour activity in tumours, but its mechanism remains unknown. The human CRC cell lines HCT116, RKO, and SW480 and immunodeficient mice were used as models to study the effects of gracillin on cell proliferation, migration and apoptosis. These were evaluated by cell viability, colony formation, wound-healing migration and cell apoptosis assays. Luciferase reporter assay, and immunostaining and western blot analyses were used to explore the specific mechanism through which gracillin exerts its effects. Gracillin significantly reduces viability and migration and stimulates apoptosis in human CRC cells. It also significantly inhibits tumour growth with no apparent physiological toxicity in animal model experiments. Moreover, gracillin is found to inhibit STAT3 phosphorylation and STAT3 target gene products. In addition, gracillin inhibits IL6-induced nuclear translocation of P-STAT3. Gracillin shows potent efficacy against CRC by inhibiting the STAT3 pathway. It should be further explored as a unique STAT3 inhibitor for the treatment of CRC.

Alantolactone promotes ER stress-mediated apoptosis by inhibition of TrxR1 in triple-negative breast cancer cell lines and in a mouse model.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor clinical outcome and currently no effective targeted therapies are available. Alantolactone (ATL), a sesquiterpene lactone, has been shown to have potential anti-tumour activity against various cancer cells. However, the underlying mechanism and therapeutic effect of ATL in the TNBC are largely unknown. In the present study, we found that ATL suppresses TNBC cell viability by reactive oxygen species (ROS) accumulation and subsequent ROS-dependent endoplasmic reticulum (ER) stress both in vitro and in vivo. Thioredoxin reductase 1 (TrxR1) expression and activity of were significantly up-regulated in the TNBC tissue specimens compare to the normal adjacent tissues. Further analyses showed that ATL inhibits the activity of TrxR1 both in vitro and in vivo in TNBC and knockdown of TrxR1 in TNBC cells sensitized ATL-induced cell apoptosis and ROS increase. These results will provide pre-clinical evidences that ATL could be a potential therapeutic agent against TNBC by promoting ROS-ER stress-mediated apoptosis through partly targeting TrxR1.

Dihydroartemisinin enhances the anti-tumor activity of oxaliplatin in colorectal cancer cells by altering PRDX2-reactive oxygen species-mediated multiple signaling pathways.

BACKGROUND: Globally, colorectal cancer (CRC) is one of the leading causes of cancer-related deaths. Oxaliplatin based treatments are frequently used as chemotherapeutic methods for CRC, however, associated side effects and drug resistance often limit their clinical application. Dihydroartemisinin (DHA) induces apoptosis in various cancer cells by increasing reactive oxygen species (ROS) production. However, the direct target of DHA and underlying molecular mechanisms in oxaliplatin-mediated anti-tumor activities against CRC are unclear. METHODS: We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), flow cytometry, and colony formation assays to investigate cell phenotype alterations and ROS generation. We also used quantitative Real-Time PCR (qRT-PCR) and western blotting to measure relative gene and protein expression. Finally, an in vivo mouse xenograft model was used to assess the anti-tumor activity of oxaliplatin and DHA alone, and combinations. RESULTS: DHA synergistically enhanced the anti-tumor activity of oxaliplatin in colon cancer cells by regulating ROS-mediated ER stress, signal transducer and activator of transcription 3 (STAT3), C-Jun-amino-terminal kinase (JNK), and p38 signaling pathways. Mechanistically, DHA increased ROS levels by inhibiting peroxiredoxin 2 (PRDX2) expression, and PRDX2 knockdown sensitized DHA-mediated cell growth inhibition and ROS production in CRC cells. A mouse xenograft model showed strong anti-tumor effects from combination treatments when compared with single agents. CONCLUSIONS: We demonstrated an improved therapeutic strategy for CRC patients by combining DHA and oxaliplatin treatments.

Novel Regulatory Factors and Small-Molecule Inhibitors of FGFR4 in Cancer.

Fibroblast growth factor receptor 4 (FGFR4) is a tyrosine kinase receptor that is a member of the fibroblast growth factor receptor family and is stimulated by highly regulated ligand binding. Excessive expression of the receptor and its ligand, especially FGF19, occurs in many types of cancer. Abnormal FGFR4 production explains these cancer formations, and therefore, this receptor has emerged as a potential target for inhibiting cancer development. This review discusses the diverse mechanisms of oncogenic activation of FGFR4 and highlights some currently available inhibitors targeting FGFR4.

Curcumin derivative WZ35 inhibits tumor cell growth via ROS-YAP-JNK signaling pathway in breast cancer.

BACKGROUND: Breast cancer is the most prevalent cancer among women worldwide. WZ35, an analog of curcumin, has been demonstrated to remarkably improve the pharmacokinetic profiles in vivo compared with curcumin. WZ35 exhibits promising antitumor activity in gastric cancer, HCC, colon cancer. However, antitumor effects of WZ35 in breast cancer and its underlying molecular mechanisms remain unclear. METHODS: CCK8, Flow cytometry and transwell assays were used to measure cell proliferation, cell cycle arrest, apoptosis, cell migration and invasion. We constructed xenograft mouse model and lung metastasis model to assess the antitumor activities of WZ35 in vivo. To explore the underlying molecular mechanisms of WZ35, we performed a series of overexpression and knockdown experiments. The cellular oxygen consumption rates (OCRs) was measured to assess mitochondrial dysfunction. RESULTS: We found that treatment of breast cancer cells with WZ35 exerts stronger anti-tumor activities than curcumin both in vitro and in vivo. Mechanistically, our research showed that WZ35 induced reactive oxygen species (ROS) generation and subsequent YAP mediated JNK activation in breast cancer cells. Abrogation of ROS production markedly attenuated WZ35 induced anti-tumor activities as well as YAP and JNK activation. In addition, ROS mediated YAP and JNK activation induced mitochondrial dysfunction in breast cancer cells. CONCLUSION: Our study showed that novel anti-cancer mechanisms of WZ35 in breast cancer cells and ROS-YAP-JNK pathway might be a potential therapeutic target for the treatment of breast cancer patients.

[Recombinant adenovirus of microRNA-193b inhibits proliferation of K562 cells].

OBJECTIVE: To construct a recombinant adenovirus vector containing human pre-miR-193b and investigate its effect on the proliferation of chronic myelocytic leukemia K562 cells. METHODS: The cDNA of pre-miR-193b was obtained by chemical synthesis and inserted into the adenoviral shuttle vector pAdTrack-CMV. The recombinant shuttle plasmid was linearized by Pme I and transformed into AdEasier cells for homologous recombination in E.coli BJ5183 with the adenoviral backbone plasmid pAdEasy-1. The recombinant adenoviral plasmid was linearized by Pac I and then used for transfecting HEK293 cells. After package and amplification in HEK293 cells, the virus titer was determined by serial dilution assay. The expression level of miR-193b in K562 cells was detected by real-time quantitative PCR. The cell proliferation was observed by MTT assay. RESULTS: The recombinant plasmid named pAd-miR-193b was confirmed by restriction enzyme analysis and sequencing. The recombinant adenovirus could infect K562 cells efficiently. Compared with control group, real-time quantitative PCR revealed that the expression of miR-193b was significantly up-regulated in K562 cells infected with pAd-pre-miR-193b, and the cell proliferation was suppressed significantly in K562 cells with up-regulated miR-193b expression. CONCLUSION: The over-expression of miR-193b may suppress the proliferation of K562 cells.

[Inhibitory effect of the recombinant adenovirus pre-miR-10a on K562 cell proliferation].

AIM: To investigate the changes of proliferation and apoptosis in K562 cells over-expressing miR-10a. METHODS: K562 cells were infected with pAd-pre-miR-10a virus, and then the levels of miR-10a and bcr/abl in transfected K562 cells was detected using RT-PCR and the level of BCR/ABL using Western blotting. The methylthiazolyl tetrazolium (MTT) assay and flow cytometry (FCM) were used to monitor the changes of proliferation and apoptosis of K562 cells after transfection. RESULTS: Compared with the control groups, K562 cells transfected with pAd-pre-miR-10a presented the significantly increased level of miR-10a, the significantly decreased expressions of bcr/abl fusion gene and BCR/ABL fusion protein, the inhibited proliferation ability and the promoted apoptosis (P<0.05). CONCLUSION: The recombinant adenovirus of pAd-pre-miR-10a can inhibit the proliferation of K562 cells and promote cell apoptosis significantly.