Combined aspirin and apatinib treatment suppresses gastric cancer cell proliferation

Circular Sponge against miR-21 Enhances the Antitumor Activity of Doxorubicin against Breast Cancer Cells

Breast cancer is the most common type of cancer in women, with chemotherapy being the main strategy. However, its effectiveness is reduced by drug resistance mechanisms. miR-21 is upregulated in breast cancer that has been linked to drug resistance and carcinogenic processes. Our aim was to capture miR-21 with a circular sponge (Circ-21) and thus inhibit the carcinogenic processes and drug resistance mechanisms in which it participates. Proliferation, migration, colony formation, cell cycle, and poly [ADP-ribose] polymerase 1 (PARP-1) and vascular endothelial growth factor (VEGF) detection assays were performed with MCF7 breast cancer cells and MCF10A non-tumor cells. In addition, doxorubicin resistance tests and detection of drug resistance gene expression were performed in MCF7 cells. Reduction in proliferation, as well as migration and colony formation, increased PARP-1 expression, inhibition of VEGF expression and cell cycle arrest in G2/M phase were displayed in the Circ-21 MCF7, which were not observed in the MCF10A cells. Furthermore, in the MCF7 cells, the Circ-21 enhanced the antitumor activity of doxorubicin and decreased the expression of resistance genes: ABCA1, ABCC4, and ABCC5. Based on these results, the use of Circ-21 can be considered a first step for the establishment of an effective gene therapy in the treatment of breast cancer.

Noncoding RNA Roles in Pharmacogenomic Responses to Aspirin: New Molecular Mechanisms for an Old Drug

Aspirin, as one of the most frequently prescribed drugs, can have therapeutic effects on different conditions such as cardiovascular and metabolic disorders and malignancies. The effects of this common cardiovascular drug are exerted through different molecular and cellular pathways. Altered noncoding RNA (ncRNA) expression profiles during aspirin treatments indicate a close relationship between these regulatory molecules and aspirin effects through regulating gene expressions. A better understanding of the molecular networks contributing to aspirin efficacy would help optimize efficient therapies for this very popular drug. This review is aimed at discussing and highlighting the identified interactions between aspirin and ncRNAs and their targeting pathways and better understanding pharmacogenetic responses to aspirin.

Aspirin enhances the therapeutic efficacy of cisplatin in oesophageal squamous cell carcinoma by inhibition of putative cancer stem cells

BACKGROUND

Cancer stem cells (CSCs) are related to the patient's prognosis, recurrence and therapy resistance in oesophageal squamous cell carcinoma (ESCC). Although increasing evidence suggests that aspirin (acetylsalicylic acid, ASA) could lower the incidence and improve the prognosis of ESCC, the mechanism(s) remains to be fully understood.

METHODS

We investigated the role of ASA in chemotherapy/chemoprevention in human ESCC cell lines and an N-nitrosomethylbenzylamine-induced rat ESCC carcinogenesis model. The effects of combined treatment with ASA/cisplatin on ESCC cell lines were examined in vitro and in vivo. Sphere-forming cells enriched with putative CSCs (pCSCs) were used to investigate the effect of ASA in CSCs. Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) was performed to determine the alterations in chromatin accessibility caused by ASA in ESCC cells.

RESULTS

ASA inhibits the CSC properties and enhances cisplatin treatment in human ESCC cells. ATAC-seq indicates that ASA treatment results in remarkable epigenetic alterations on chromatin in ESCC cells, especially their pCSCs, through the modification of histone acetylation levels. The epigenetic changes activate Bim expression and promote cell death in CSCs of ESCC. Furthermore, ASA prevents the carcinogenesis of NMBzA-induced ESCC in the rat model.

CONCLUSIONS

ASA could be a potential chemotherapeutic adjuvant and chemopreventive drug for ESCC treatment.

Gastric cancer-secreted exosomal X26nt increases angiogenesis and vascular permeability by targeting VE-cadherin

Angiogenesis is closely associated with tumorigenesis, invasion, and metastasis by providing oxygen and nutrients. Recently, increasing evidence indicates that cancer-derived exosomes which contain proteins, coding, and noncoding RNAs (ncRNAs) were shown to have proangiogenic function in cancer. A 26-nt-long ncRNA (X26nt) is generated in the process of inositol-requiring enzyme 1 alpha (IRE1α)-induced unspliced XBP1 splicing. However, the role of X26nt in the angiogenesis of gastric cancer (GC) remains largely unknown. In the present study, we found that X26nt was significantly elevated in GC and GC exosomes. Then, we verified that X26nt could be delivered into human umbilical vein endothelial cells (HUVECs) via GC cell exosomes and promote the proliferation, migration, and tube formation of HUVECs. We revealed that exosomal X26nt decreased vascular endothelial cadherin (VE-cadherin) by directly combining the 3'UTR of VE-cadherin mRNA in HUVECs, thereby increasing vascular permeability. We further demonstrated that X26nt accelerates the tumor growth and angiogenesis in a mouse subcutaneous tumor model. Our findings investigate a unique intercellular communication mediated by cancer-derived exosomes and reveal a novel mechanism of exosomal X26nt in the regulation of tumor vasculature.

Exosomal miR-487a derived from m2 macrophage promotes the progression of gastric cancer

Tumor-associated macrophages contribute to cell growth, development, and metastasis in various cancers. However, the underlying mechanisms of M2 macrophage that modulate the progression of gastric cancer (GC) remain largely unknown. In this study, we detected the ratio of macrophages in GC tissues and found that the proportion of M2 macrophages was increased in GC tissues. We then co-cultured GC cells with M1 and M2 macrophages, respectively, and then assessed cell proliferation and tumorigenicity of GC cells by MTT and colony formation assay. The results indicated that M2 macrophages promoted the proliferation of GC cells, but M1 not. Besides, GW4869, an exosomes inhibitor, reduced the effects induced by M2 macrophage. Then, we isolated and identified exosomes derived from M1 and M2 macrophage, and confirmed that the exosomes could be taken up by GC cells. We demonstrated that M2 macrophage-exosomes could induce the proliferation and tumorigenesis in vitro and in vivo. Moreover, miR-487a was enriched in M2 macrophage-exosomes and further determined that miR-487a exert the functions by targeting TIA1. In conclusion, exosomal miR-487a derived from M2 macrophage promotes the proliferation and tumorigenesis in gastric cancer, and the novel findings might be helpful to the development of novel diagnostic and therapeutic methods in GC.

Aspirin sensitizes osimertinib-resistant NSCLC cells in vitro and in vivo via Bim-dependent apoptosis induction

Osimertinib, a third-generation irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), provides marked clinical benefit for patients with EGFR-activating mutations. Unfortunately, limited treatments exist for patients who acquire osimertinib resistance. We observed two 'special' patients who regained an antitumor response with osimertinib plus aspirin treatment. As previous data indicate that aspirin induces antiproliferative effects in tumor cells, we designed a preclinical study to explore whether aspirin combined with osimertinib could synergistically sensitize osimertinib-resistant non-small-cell lung cancer (NSCLC) cells. The effects of combined treatment with osimertinib and aspirin on osimertinib-resistant NSCLC cell lines were examined in vitro and in vivo. The combination of osimertinib and aspirin induced strong antiproliferative and proapoptotic effects in osimertinib-resistant NSCLC cells through inhibition of Akt/FoxO3a signaling component phosphorylation and increased Bim expression. Furthermore, Bim knockdown by siRNA significantly attenuated osimertinib resensitization by aspirin. In vivo, combination of aspirin and osimertinib significantly decreased tumor growth of PC-9GROR cell xenografts. Data of patients with NSCLC who received osimertinib treatment at Daping Hospital between January 2015 and January 2019 were reviewed retrospectively. According to clinical data for 45 patients with NSCLC, retrospective analysis showed that the median progression-free survival was significantly longer in the osimertinib plus aspirin group than in the osimertinib group. In summary, aspirin synergistically enhances the antitumor activity of osimertinib in osimertinib-resistant lung cancer cells through promoting Bim-dependent apoptosis. This combination therapy may be effective in overcoming acquired resistance to osimertinib and prolonging survival in patients with NSCLC.

Research Progress in microRNA-Based Therapy for Gastric Cancer

Gastric cancer (GC) is one of the leading causes of tumor-related mortality. In addition to surgery and endoscopic resection, systemic therapy remains the main treatment option for GC, especially for advanced-stage disease and for cases not suitable for surgical therapy. Hence, improving the efficacy of systemic therapy is still an urgent problem to overcome. In the past decade, the essential roles of microRNAs (miRNAs) in tumor treatment have been increasingly recognized. In particular, miRNAs were recently shown to reverse the resistance to chemotherapy drugs such as 5-fluorouracil, cisplatin, and doxorubicin. Synthesized nanoparticles loaded with mimics or inhibitors of miRNAs can directly target tumor cells to suppress their growth. Moreover, exosomes may serve as promising safe carriers for mimics or inhibitors of miRNAs to treat GC. Some miRNAs have also been shown to play roles in the mechanism of action of other anti-tumor drugs. Therefore, in this review, we highlight the research progress on microRNA-based therapy in GC and discuss the challenges and prospects associated with this strategy. We believe that microRNA-based therapy has the potential to offer a clinical benefit to GC patients, and this review would contribute to and motivate further research to promote this field toward this ultimate goal.

miR-135b Delivered by Gastric Tumor Exosomes Inhibits FOXO1 Expression in Endothelial Cells and Promotes Angiogenesis

Exosomes, which act as mediators of intercellular communication, are nanoscale membrane vesicles that contain proteins, lipids, mRNAs, and microRNAs (miRNAs). Additionally, exosomes play a significant role in the development of tumors. The robust angiogenesis of gastric cancer (GC) is one of the reasons for its rampant growth. Drugs and other treatments are not good solutions for the problem of angiogenesis in GC. Here we found that exosome-delivered miRNA contributes greatly to angiogenesis in GC. The downregulation of forkhead box O1 (FOXO1) was observed in GC. After measurement of lentivirus overexpressing microRNA-135b (miR-135b) levels, we found that miR-135b and FOXO1 are negatively correlated. In addition, miR-135b was delivered to tumor cells by exosomes to take its effect on angiogenesis in GC. Exosome-containing cell cocultures and a tumor-implanted mouse model were used for in vitro and in vivo studies, respectively. We showed that miR-135b derived from GC cells suppressed the expression of FOXO1 protein and enhanced the growth of blood vessels. Our findings illustrate a novel signaling pathway comprising exosomes, miRNAs, and target genes, and they provide potential targets for anti-angiogenic therapy.

Downregulation of microRNA-4295 enhances cisplatin-induced gastric cancer cell apoptosis through the EGFR/PI3K/Akt signaling pathway by targeting LRIG1

Gastric cancer (GC) is one of the leading causes of cancer-associated mortality worldwide. The aim of the present study was to investigate the mechanism of microRNA-4295 (miR-4295), which regulates cisplatin (DDP)-induced apoptosis in GC cells through the leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1)-mediated epidermal growth factor receptor (EGFR)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. Two cell lines were selected, one with the highest expression of miR-4295 and one with the lowest expression of LRIG1, for the experiments. The half maximal inhibitory concentration of DDP in the human GC MKN-28 and MKN-45 cell lines was calculated, and mitochondrial membrane potentials of the GC cells were detected by tetramethylrhodamine, ethyl ester, perchlorate staining. The proliferation and apoptosis of GC cells with or without DDP treatment were assessed by MTT assay and plate colony formation, as well as flow cytometry and TUNEL staining. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were employed to determine the expression of EGFR/PI3K/Akt signaling pathway-related genes and apoptosis-related genes. LRIG1 was identified as a target gene of miR-4295. The expression of miR-4295 was upregulated, and the expression of LRIG1 was downregulated in GC cells. Furthermore, DDP enhanced the decrease in miR-4295 expression and the increase in LRIG1 expression in GC cells. miR-4295 promoted the proliferation and inhibited the DDP-induced apoptosis of GC cells without DDP treatment. In addition, miR-4295 increased the expression levels of EGFR, PI3K, Akt, p-PI3K and p-Akt, suggesting that miR-4295 promotes the activation of the EGFR/PI3K/Akt signaling pathway by targeting LRIG1. miR-4295 targeted and negatively regulated LRIG1 expression to activate the EGFR/PI3K/Akt signaling pathway, thereby promoting the proliferation of the GC cells and inhibiting the apoptosis of the GC cells induced by DDP. Therefore, miR-4295 may be a novel therapeutic target in patients with GC.