Nitric oxide (NO) and peroxynitrite, formed from NO and superoxide anion, have been implicated as mediators of neuronal damage following focal ischemia, but their molecular targets have not been defined. One candidate pathway is DNA damage leading to activation of the nuclear enzyme, poly(ADP-ribose) polymerase (PARP), which catalyzes attachment of ADP ribose units from NAD to nuclear proteins following DNA damage. Excessive activation of PARP can deplete NAD and ATP, which is consumed in regeneration of NAD, leading to cell death by energy depletion. We show that genetic disruption of PARP provides profound protection against glutamate-NO-mediated ischemic insults in vitro and major decreases in infarct volume after reversible middle cerebral artery occlusion. These results provide compelling evidence for a primary involvement of PARP activation in neuronal damage following focal ischemia and suggest that therapies designed towards inhibiting PARP may provide benefit in the treatment of cerebrovascular disease.

Background: Tumor recurrence and metastasis occur at a high rate in patients with colon cancer. Identification of effective strategies for the treatment of colon cancer is critical. Recently, poly (lactic-co-glycolic acid) (PLGA) has been shown to have potential as a broad therapeutic drug delivery system. We designed a dual-loaded nanoparticle drug delivery system to overcome the limitations of chemotherapeutic drugs used to treat colon cancer. Methods: We developed epidermal growth factor (EGF) functionalized PLGA nanoparticles (NPs) co-loaded with 5fluorouracil (5Fu) and perfluorocarbon (PFC) (EGF-PLGA@5Fu/PFC) for targeted treatment of colon cancer. CCK-8 assay, Hoechst33342 staining and flow cytometry were performed to investigate the functions of EGF-PLGA@5Fu/ PFC NPs in SW620 cells. Beside, animal experiment, histological analysis and immunofluorescence staining were adopted to further confirm the role of EGF-PLGA@5Fu/PFC NPs in vivo. Results: The findings showed that EGF-PLGA@5Fu /PFC NPs had an average size 200 nm and a 5Fu-loading efficiency of 7.29%. Furthermore, in vitro release was pH-sensitive. Targeted EGF-PLGA@5Fu/PFC NPs exhibited higher cellular uptake than non-targeted NPs into colon cancer cells. In addition, EGF-PLGA@5Fu/PFC NPs suppressed cell viability and induced apoptosis in SW620 cells to a greater extent than non-targeted NPs. In tumor xenografted mice, EGF-PLGA@5Fu/PFC NPs suppressed tumor growth more effectively than 5Fu, PLGA@5Fu or PLGA@5Fu/PFC NPs. Histopathological analysis further demonstrated that EGF-targeted NPs inhibited tumor growth to a greater extent than non-targeted or non-NP treatments. The improved therapeutic outcomes observed in this study were due to relief of tumor hypoxia by transport of oxygen by PFC to the tumors. Conclusion: We constructed a biocompatible nanodrug delivery system based on functionalized nanoparticles that provided a novel strategy for selective delivery of chemotherapy drugs to tumors.

Breast cancer is a malignancy arising in the mammary epithelial tissues. Recent studies have indicated the abundance of microRNAs (miRNAs) in extracellular vesicles (EVs), and their interactions have been illustrated to exert crucial roles in the cell‐to‐cell communication. The present study focused on investigating whether EV‐delivered miR‐370‐3p affects breast cancer. Initially, the miR‐370‐3p expression pattern was examined in the cancer‐associated fibroblasts (CAFs), normal fibroblasts (NFs), and cancerous cells‐derived EVs. The relation of miR‐370‐3p to CYLD was assessed using luciferase activity assay. Afterwards, based on ectopic expression and depletion experiments in the MCF‐7 breast cancer cells, we evaluated stemness, migration, invasion, and sphere formation ability, and EMT, accompanied with measurement on the expression patterns of pro‐inflammatory factors and nuclear factor‐kappa B (NF‐κB) signaling‐related genes. Finally, tumorigenesis and proliferation were analyzed in vivo using a nude mouse xenograft model. The in vitro experiments revealed that breast cancer cell‐derived EVs promoted NF activation, while activated fibroblasts contributed to enhanced stemness, migration, invasion, as well as EMT of cancerous cells. In addition, EVs could transfer miR‐370‐3p from breast cancer cells to NFs, and EV‐encapsulated miR‐370‐3p was also found to facilitate fibroblast activation. Mechanistically, EV‐encapsulated miR‐370‐3p downregulated the expression of CYLD through binding to its 3′UTR and activated the NF‐κB signaling pathway, thereby promoting the cellular functions in vitro and in vivo in breast cancer. Taken together, EVs secreted by breast cancer cells could carry miR‐370‐3p to aggravate breast cancer through downregulating CYLD expression and activating the NF‐κB signaling pathway.

Background: Protein arginine methyltransferase 5 (PRMT5) is a type II arginine methyltransferase that symmetrically di-methylates arginine residues on both histone and non-histone protein substrates. Accumulating evidence suggests that PRMT5 exerts its oncogenic properties in a wide spectrum of human malignancies. However, the underlying mechanisms by which PRMT5 contributes to the progression of colorectal cancer (CRC) remain to be defined. Methods: Western blot and real-time PCR were used to analyze the expression of CDKN2B. Co-immunoprecipitation (Co-IP), immunofluorescence and GST pulldown assays were employed to investigate the interaction between PRMT5 and EZH2. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were performed to validate CDKN2B as a direct target of PRMT5/EZH2. DNA methylation status at the CpG islands of promoter region of CDKN2B gene was analyzed by bisulfite sequencing. The effect of PRMT5/EZH2 on malignant phenotypes was examined through in vitro and in vivo assays. PRMT5 and EZH2 protein expression levels in CRC tissues were analyzed by immunohistochemistry (IHC) staining. Results: We observed that PRMT5-deficient CRC cells exhibit proliferation defects in vitro . PRMT5 was identified as a major transcriptional repressor of CDKN2B (p15 INK4b ) for determining CRC progression. Mechanistically, PRMT5-mediated histone marks H4R3me2s and H3R8me2s were predominantly deposited at the promoter region of CDKN2B gene in CRC cells. Knockdown of PRMT5 in CRC cells decreased the accumulation of H4R3me2s and H3R8me2s marks and reduced the CpG methylation level of CDKN2B promoter, then re-activated CDKN2B expression. Strikingly, silencing of CDKN2B partially abrogated the proliferation defects caused by PRMT5 depletion in vitro and in vivo . Furthermore, we proved that PRMT5 interacted with Enhancer of zeste homolog 2 (EZH2), leading to enhanced EZH2 binding and H3K27me3 deposition together with decreased transcriptional output of CDKN2B gene. Importantly, we found that the combined interventions exerted a synergistic inhibitory effect of combined treatment with PRMT5i (GSK591) and EZH2i (GSK126) on the growth of CRC cells/xenografts in vitro and in vivo . Moreover, PRMT5 and EZH2 were found to be significantly elevated and associated with poor prognosis in CRC patients. Conclusion: PRMT5 functionally associates with EZH2 to promote CRC progression through epigenetically repressing CDKN2B expression. Thus, our findings raise the possibility that combinational intervention of PRMT5 and EZH2 may be a promising strategy for CRC therapy.

Background It has been well documented that long non-coding RNAs (lncRNAs) regulate numerous characteristics of cancer, including proliferation, migration, metastasis, apoptosis, and even metabolism. LncRNA BCYRN1 (BCYRN1) is a newly identified brain cytoplasmic lncRNA with 200 nucleotides that was discovered to be highly expressed in tumour tissues, including those of hepatocellular carcinoma, gastric cancer and lung cancer. However, the roles of BCYRN1 in colorectal cancer (CRC) remain obscure. This study was designed to reveal the role of BCYRN1 in the occurrence and progression of CRC. Methods RT-PCR was used to detect the expression level of BCYRN1 in tumour tissues and CRC cell lines. BCYRN1 was knocked down in CRC cells, and cell proliferation changes were evaluated by cell counting kit-8 (CCK-8), 5-ethynyl-2′-deoxyuridine (EdU), and Ki-67 and proliferating cell nuclear antigen (PCNA) expression assays. Cell migration and invasion changes were evaluated by wound healing, Transwell and invasion-related protein expression assays. Flow cytometry analysis was used to assess whether BCYRN1 regulates the apoptosis of CRC cells. The dual luciferase reporter gene detects the competitive binding of BCYRN1 to miR-204-3p. In vivo experiments were performed to evaluate the effect of BCYRN1 on tumour development. TargetScan analysis and dual luciferase reporter gene assays were applied to detect the target gene of miR-204-3p. Rescue experiments verified that BCYRN1 affects CRC by regulating the effect of miR-204-3p on KRAS. Results We found that compared with normal tissues and human intestinal epithelial cells (HIECs), CRC tumour tissues and cell lines had significantly increased BCYRN1 levels. We further determined that knockdown of BCYRN1 inhibited the proliferation, migration, and invasion and promoted the apoptosis of CRC cells. In addition, bioinformatics analysis and dual luciferase reporter assay showed that BCYRN1 served as a competitive endogenous RNA (ceRNA) to regulate the development of CRC through competitively binding to miR-204-3p. Further studies proved that overexpression of miR-204-3p reversed the effects of BCYRN1 on CRC. Next, TargetScan analysis and dual luciferase reporter assay indicated that KRAS is a target gene of miR-204-3p and is negatively regulated by miR-204-3p. A series of rescue experiments showed that BCYRN1 affected the occurrence and development of CRC by regulating the effects of miR-204-3p on KRAS. In addition, tumorigenesis experiments in a CRC mouse model confirmed that BCYRN1 downregulation effectively inhibited tumour growth. Conclusions Our findings suggest that BCYRN1 plays a carcinogenic role in CRC by regulating the miR-204-3p/KRAS axis.

Despite recent improvements in the comprehensive therapy of malignancy, metastatic colorectal cancer (mCRC) continues to have a poor prognosis. Notably, 5% of mCRC cases harbor Erb-B2 receptor tyrosine kinase 2 (ERBB2) alterations. ERBB2, commonly referred to as human epidermal growth factor receptor 2, is a member of the human epidermal growth factor receptor family of protein tyrosine kinases. In addition to being a recognized therapeutic target in the treatment of gastric and breast malignancies, it is considered crucial in the management of CRC. In this review, we describe the molecular biology of ERBB2 from the perspective of biomarkers for mCRC-targeted therapy, including receptor structures, signaling pathways, gene alterations, and their detection methods. We also discuss the relationship between ERBB2 aberrations and the underlying mechanisms of resistance to anti-EGFR therapy and immunotherapy tolerance in these patients with a focus on novel targeted therapeutics and ongoing clinical trials. This may aid the development of a new standard of care in patients with ERBB2-positive mCRC.

We investigated the function of circular RNA circEIF3M (hsa_circ_0003119) in triple-negative breast cancer. The expression profiles of circRNAs in 3 specimens of triple-negative breast cancer tissues with adjacent nontumor tissues were analyzed by RNA-sequencing. We verified the oncogenic role of circEIF3M in triple-negative breast cancer through a series of biological function experiments. It was found that circEIF3M was markedly upregulated in triple-negative breast cancer as compared to adjacent nontumor tissue, and that circEIF3M promoted triple-negative breast cancer cell proliferation, migration, and invasion. Mechanistic analysis indicated that circEIF3M may act as a competing endogenous RNA for miR-33a that relieves the inhibitory effect of miR-33a on its target cyclin D1. These findings showed that circEIF3M promotes triple-negative breast cancer progression via the circEIF3M/ miR-33a/ cyclin D1 axis.

The interactions of nanomaterials with biological materials such as immortalized cell lines are recently on the rise. Owing to this superiority, the biosynthesis of AgNPs using gallic acid as a reductant was implemented in this study. After being synthesized, the AgNPs were characterized using techniques such as dynamic light scattering, transmission electron microscopy, selected area electron diffraction, and X-ray diffraction methods. Furthermore, the AgNPs were assessed for their cytotoxic effects on the colorectal adenocarcinoma cell line HT-29. The mechanisms of such cell-killing effect were investigated by analyzing the expressions of 14 mRNAs using quantitative polymerase chain reaction. The outcomes indicate that the synthesized AgNPs were cytotoxic on HT-29 cells. The expressions of all apoptotic genes analyzed including cyt-C, p53, Bax, Bcl2, CASP3, CASP8, CASP9, and CASP12 were upregulated. With regard to the autophagy-related genes, Beclin-1, XBP-1, CHOP, and LC3-II were upregulated, whereas the expressions of ATG3 and ATG12 were downregulated. To conclude, the AgNPs induced mitochondria-dependent apoptosis and non-canonical autophagy in HT-29 cells. A crosstalk did occur between autophagy and apoptosis in such a cell-killing effect. Hence, further studies are required to elucidate the exact mechanisms in animal models for further use of AgNPs in clinical medicine for the treatment of neoplasms of the digestive tract.