RNA interference (RNAi) has emerged as a powerful tool for developing novel management strategies for controlling insect pests. The 28-spotted ladybeetle, Henosepilachna vigintioctopunctata is one of the most important pests attacking solanaceous plants in Asia. In this study, the potential of dietary RNAi to manage H. vigintioctopunctata was investigated using both in vitro synthesized and bacterially expressed double-stranded RNAs (dsRNAs) of HvvATPase A and HvvATPase E. The expression levels of HvvATPase A and HvvATPase E were higher in Malpighian tubules than in other tissue types. The silencing of HvvATPase A and HvvATPase E led to significant mortality in H. vigintioctopunctata larvae. In addition, the ingestion of HvvATPase A and HvvATPase E significantly deterred feeding behavior and subsequently arrested the development of H. vigintioctopunctata. Notably, the bacterially expressed dsRNAs consistently caused higher mortality in larvae and adults. Finally, the nontarget effects of the dsRNAs of H. vigintioctopunctata on the predatory ladybeetle Propylaea japonica were evaluated. P. japonica 1st instar larvae were administered vATPase A and vATPase E dsRNAs from H. vigintioctopunctata and P. japonica under the worst-case scenario, in which dsGFP served as negative control. There were significant effects of dsHvvATPase A on P. japonica at the transcriptional level but not at the organismal level, whereas dsHvvATPase E did not effect P. japonica at either the transcriptional or the organismal level. Collectively, the results of the study suggest that HvvATPase A and HvvATPase E can act as novel molecular targets for the control of H. vigintioctopunctata.
<p>Supplemental Figures 1-7. Figure S1. IRF8 expression profiles in subsets of immune cells in spleens of tumor-bearing mice. Figure S2. IRF8 expression profiles in subsets of immune cells in peripheral blood of tumor-bearing mice. Figure S3. DNA methylation and MDSC accumulation in tumor-bearing mice. Figure S4. Inhibition of DNA methylation activates antigen-specific CTLs in tumor-bearing mice. Figure S5. Neutralization of TNFα increases tumor growth and MDSC accumulation. Figure S6. RIP1 and RIP3 are expressed in MDSCs. Figure S7. IL6 expression level in human colon carcinoma and melanoma. Table S1. Colorectal cancer patient data. Table S2. Colon cancer patient data.</p>
This study aims to investigate the effects of targeted regulation of Mst1 (Mammalian sterile 20-like kinase 1) expression on the proliferation and apoptosis of SW480 colorectal cancer cells and to elucidate the mechanisms underlying these effects. PolyJetTM in vitro DNA transfection reagent was used to transfect pEGFP-N1-Mst1 into SW480 colorectal cancer cells, and LipofectamineTM2000 was used to transfect Mst1-specific siRNA for the targeted silencing of Mst1. MTT assay was then performed to detect the survival rate of the cells, flow cytometry was used to determine apoptosis, and RT-qPCR and western blot were used to measure the mRNA and protein levels of Mst1, PUMA, p73, p53, YAP (Yes Associated Protein 1), and caspase-3. Compared with the control group, the p-EGFP-Mst1 and p-EGFPMst1+ 5-FU groups showed significantly higher rate of cell proliferation inhibition and apoptosis (P<0.05). The protein levels of MST1, Phospho-YAP1 (Ser127), P73, P53, PUMA, and Caspase-3 were significantly increased (P<0.05), while the protein levels of CTGF (Connective Tissue Growth Factor) and AREG (Amphiregulin) were significantly reduced (P<0.05). In the Mst1-siRNA group, the apoptosis rate was significantly decreased (P<0.01), cell proliferation was accelerated, p73, p53, and PUMA were downregulated, and CTGF, AREG, and YAP were upregulated. The targeted regulation of Mst1 expression significantly affected the proliferation and apoptosis of the SW480 cells. Thus, Mst1 has potential for use as a new target for the prevention and treatment of colorectal cancer.
Tumor occurrence, progression and metastasis depend on the crosstalk between tumor cells and stromal cells and on extrinsic factors outside the tumor microenvironment. Exosomal microRNA (miRNA) not only is involved in communications within the tumor microenvironment but also mediates communications between the extrinsic environment and tumor microenvironment. However, most reviews have been limited to the role of endogenous exosomal miRNA in remodeling the tumor microenvironment. Hence, we herein review the role of endogenous exosomal miRNA in mediating intercellular crosstalk within the tumor microenvironment, inducing the formation of the premetastatic niche. To place our vision outside the microenvironment, we also summarize for the first time the most recent studies regarding how exogenous miRNA derived from milk, plants and microbes influences the tumor microenvironment. Furthermore, to improve the value of exosomal miRNA in cancer research and clinical applications, we also provide some novel ideas for future research based on the comprehensive role of exosomal miRNA in remodeling the tumor microenvironment.
<div>Abstract<p>Although accumulation of myeloid-derived suppressor cells (MDSC) is a hallmark of cancer, the underlying mechanism of this accumulation within the tumor microenvironment remains incompletely understood. We report here that TNFα–RIP1–mediated necroptosis regulates accumulation of MDSCs. In tumor-bearing mice, pharmacologic inhibition of DNMT with the DNA methyltransferease inhibitor decitabine (DAC) decreased MDSC accumulation and increased activation of antigen-specific cytotoxic T lymphocytes. DAC-induced decreases in MDSC accumulation correlated with increased expression of the myeloid cell lineage-specific transcription factor IRF8 in MDSCs. However, DAC also suppressed MDSC-like cell accumulation in IRF8-deficient mice, indicating that DNA methylation may regulate MDSC survival through an IRF8-independent mechanism. Instead, DAC decreased MDSC accumulation by increasing cell death via disrupting DNA methylation of RIP1-dependent targets of necroptosis. Genome-wide DNA bisulfite sequencing revealed that the <i>Tnf</i> promoter was hypermethylated in tumor-induced MDSCs <i>in vivo</i>. DAC treatment dramatically increased TNFα levels in MDSC <i>in vitro</i>, and neutralizing TNFα significantly increased MDSC accumulation and tumor growth in tumor-bearing mice <i>in vivo</i>. Recombinant TNFα induced MDSC cell death in a dose- and RIP1-dependent manner. IL6 was abundantly expressed in MDSCs in tumor-bearing mice and patients with human colorectal cancer. <i>In vitro</i>, IL6 treatment of MDSC-like cells activated STAT3, increased expression of DNMT1 and DNMT3b, and enhanced survival. Overall, our findings reveal that MDSCs establish a STAT3–DNMT epigenetic axis, regulated by autocrine IL6, to silence TNFα expression. This results in decreased TNFα-induced and RIP1-dependent necroptosis to sustain survival and accumulation.</p>Significance:<p>These findings demonstrate that targeting IL6 expression or function represent potentially effective approaches to suppress MDSC survival and accumulation in the tumor microenvironment.</p></div>
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)