scholarly journals PIWIL1 promotes gastric cancer via a piRNA-independent mechanism

2020 ◽  
Vol 117 (36) ◽  
pp. 22390-22401 ◽  
Author(s):  
Shuo Shi ◽  
Zhen-Zhen Yang ◽  
Sanhong Liu ◽  
Fan Yang ◽  
Haifan Lin

Targeted cancer therapy aims to achieve specific elimination of cancerous but not normal cells. Recently, PIWI proteins, a subfamily of the PAZ-PIWI domain (PPD) protein family, have emerged as promising candidates for targeted cancer therapy. PPD proteins are essential for small noncoding RNA pathways. The Argonaute subfamily partners with microRNA and small interfering RNA, whereas the PIWI subfamily partners with PIWI-interacting RNA (piRNA). Both PIWI proteins and piRNA are mostly expressed in the germline and best known for their function in transposon silencing, with no detectable function in mammalian somatic tissues. However, PIWI proteins become aberrantly expressed in multiple types of somatic cancers, thus gaining interest in targeted therapy. Despite this, little is known about the regulatory mechanism of PIWI proteins in cancer. Here we report that one of the four PIWI proteins in humans, PIWIL1, is highly expressed in gastric cancer tissues and cell lines. Knocking out the PIWIL1 gene (PIWIL1-KO) drastically reduces gastric cancer cell proliferation, migration, metastasis, and tumorigenesis. RNA deep sequencing of gastric cancer cell line SNU-1 reveals that KO significantly changes the transcriptome, causing the up-regulation of most of its associated transcripts. Surprisingly, few bona fide piRNAs exist in gastric cancer cells. Furthermore, abolishing the piRNA-binding activity of PIWIL1 does not affect its oncogenic function. Thus, PIWIL1 function in gastric cancer cells is independent of piRNA. This piRNA-independent regulation involves interaction with the UPF1-mediated nonsense-mediated mRNA decay (NMD) mechanism. Altogether, our findings reveal a piRNA-independent function of PIWIL1 in promoting gastric cancer.

2020 ◽  
Author(s):  
Shuo Shi ◽  
Zhen-Zhen Yang ◽  
Sanhong Liu ◽  
Fan Yang ◽  
Haifan Lin

ABSTRACTTargeted cancer therapy aims to achieve specific elimination of cancerous but not normal cells. Recently, PIWI proteins, a subfamily of the PAZ-PIWI Domain (PPD) protein family, have emerged as promising candidates for targeted cancer therapy. PPD proteins are essential for small non-coding RNA pathways. The Argonaute subfamily partners with microRNA and small interfering RNA, whereas the PIWI subfamily partners with PIWI-interacting RNA (piRNA). Both PIWI proteins and piRNA are mostly expressed in the germline and best known for their function in transposon silencing, with no detectable function in mammalian somatic tissues. However, PIWI proteins become aberrantly expressed in multiple types of somatic cancers, thus gaining interest in targeted therapy. Despite this, little is known about the regulatory mechanism of PIWI proteins in cancer. Here we report that one of the four PIWI proteins in humans, PIWIL1, is highly expressed in gastric cancer tissues and cell lines. Knocking out PIWIL1 expression (PIWIL1-KO) drastically reduces gastric cancer cell proliferation, migration, metastasis, and tumorigenesis. RNA deep sequencing of gastric cancer cell line SNU-1 reveals that PIWIL1-KO significantly changes the transcriptome, causing the up-regulation of most of its associated transcripts. Surprisingly, few bona fide piRNAs exist in gastric cancer cells. Furthermore, abolishing the piRNA-binding activity of PIWIL1 does not affect its oncogenic function. Thus, PIWIL1 function in gastric cancer cells is independent of piRNA. This piRNA-independent regulation involves interaction with the UPF1-mediated nonsense-mediated mRNA decay (NMD) mechanism. Altogether, our findings reveal a novel and piRNA-independent function of PIWIL1 in promoting gastric cancer.SIGNIFICANCEPrecision medicine aims to cure cancer without affecting normal tissues. PIWI proteins provide a promising opportunity for precision medicine because they are normally expressed only in the testis for male fertility but gain expression in diverse types of cancers. Thus, inhibiting PIWI expression may stop cancer development (and spermatogenesis) without affecting normal body function. To establish causality between PIWI and cancer, we show here that the expression of PIWIL1, a human PIWI protein, promotes gastric cancer. Surprisingly, this oncogenic function does not require piRNA, the expected partner of PIWI proteins, but involves the nonsense-mediated mRNA decay mechanism. These findings reveal a new function and action mechanism of PIWI proteins in oncogenesis, guiding the identification of PIWI inhibitors to cure cancer.


2019 ◽  
Vol 20 (9) ◽  
pp. 719-726 ◽  
Author(s):  
Nan Li ◽  
Suyun Zhang ◽  
Qiong Luo ◽  
Fang Yuan ◽  
Rui Feng ◽  
...  

Objective: This study aimed to observe the effects of dihydroartemisinin (DHA) on the proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) of the human gastric cancer cell line SGC7901 cultured in vitro. Methods: We applied varying concentrations of DHA to SGC7901 cells. Cell proliferation was measured using the cell counting kit-8 (CCK-8). Flow cytometry, Transwell invasion assay, and cell scratch assay were used to investigate the cells’ apoptosis, invasion, and migration. Western blot was used to assess the expression levels of EMT markers E-cadhein and Vimentin, protein kinases Akt and phosphorylated AKT (p-AKT), and the cell transcription factor Snail. Results: DHA can effectively inhibit the malignant proliferation of gastric cancer cells in a time- and dose-dependent manner. In this study, with longer incubation times and increased drug concentrations, the antiproliferation effect of DHA on SGC7901 cells increased gradually (P<0.05). In addition, with the increase of drug concentration, the expression levels of E-cadhein, an epithelial-mesenchymal transition marker, remarkably increased, whereas the protein expression levels of the mesenchymal markers Vimentin, Akt, p-Akt, and Snail significantly decreased (P<0.05). Conclusion: DHA can effectively inhibit the proliferation, invasion, and metastasis of the gastric cancer cell line SGC7901 and induce cancer cell apoptosis. DHA can also downregulate PI3K/AKT and Snail activities and inhibit the epithelial-mesenchymal transition of gastric cancer cells. The potential anticancer effects of DHA deserve further investigation.


2014 ◽  
Vol 32 (3_suppl) ◽  
pp. 34-34
Author(s):  
Jungmin Park

34 Background: To establish NIR optical probe based on the HA-based supramolecular hydrogels (HASHs) conjugated with Cy5.5 for CD44-overexpressed gastric cancer imaging. Methods: To establish HASHs, Cy5.5 NHS ester was conjugated with polyethyleneimine (PEI, 25k Da) and mixed with hyaluronic acid (HA, 1M Da) by an electric interaction. The optimazed ideal molar ratio of PEI to HA was confirmed by DLS and gel electrophoresis. The CD44-expression level for various gastric cancer cell lInes (MKN1, MKN28, MKN45, MKN72, AGS, and N87 cells) was evaluated by FACS analysis. For establishment of the gastric cancer xenograft model, CD44-overexpressed gastric cancer cells were implanted into the BALB/c nude mouse's proximal thigh region. For in vitro targeting study, the cellular affinity of HASHs for CD44-low expressed gastric cancer cell line and CD44-overexpressed gastric cancer cell line was verified by confocal microscopy and IHC staing. For in vivo NIR imaging, HASHs were injected into established xenograft mouse via tail vein and NIR optical imaging was conducted time-dependently. Results: The colloidal size of HASHs was 1.4 micrometer and their morphology was confirmed by electron microscopy. CD44-expression level of MKN45 cells was 92.53% that was higher than MKN28 cells (2.66%). After the treatment of HASHs, the endocytosis into the cytosol was examined for MKN45 cells, but not observed in MKN28 cells due to the deficiency of CD44. 30 days after the transplantion of MKN45 cells, for in vivo imaging study, the prepared HASHs were intraveneously injected into tumor-bearing mouse model. By NIR optical imaging, the optical intensity at tumor site was enhanced upto 3 hours and the maximum intensity was 350 times larger than normal tissue. Conclusions: HASHs was established using supramolecular HA and Cy5.5-conjugated PEI for the targeted imaging of CD44-overexpressed gastric cancer cells. In vitro and in vivo studies demonstrated that SHAHs can visualize the individualized CD44-overexpressed gastric cancer cells by non-invasive optical imaging.


Author(s):  
Meng-Yao Sun ◽  
Bo Xu ◽  
Qiu-Xue Wu ◽  
Wen-Lian Chen ◽  
Si Cai ◽  
...  

Cisplatin is an important agent in first-line chemotherapy against gastric cancer (GC). However, consequential drug resistance limits its effectiveness for the treatment of GC. In this study, a cisplatin resistant gastric cancer cell line SGC7901R was determined by LC-MS/MS with increased exosomal levels of RPS3 protein. SGC7901R cell-derived exosomes were readily taken up by cisplatin-sensitive SGC7901S cells, thus triggering off a phenotype of chemoresistance in the receptor cells. Subsequently, it was demonstrated that exosomal RPS3 was essential for inducing chemoresistance of receptor cells as shown by the acquisition of this phenotype in SGC7901S cells with enforced expression of RPS3. Further mechanism study demonstrated that cisplatin-resistant gastric cancer cell-derived exosomal RPS3 enhanced the chemoresistance of cisplatin-sensitive gastric cancer cells through the PI3K-Akt-cofilin-1 signaling pathway. All these findings demonstrated that cisplatin-resistant gastric cancer cells communicate with sensitive cells through the intercellular delivery of exosomal RPS3 and activation of the PI3K-Akt-cofilin-1 signaling pathway. Targeting exosomal RPS3 protein in cisplatin-resistant gastric cancer cells may thus be a promising strategy to overcome cisplatin resistance in gastric cancer.


2021 ◽  
Vol 22 (14) ◽  
pp. 7698
Author(s):  
Sara Peri ◽  
Alessio Biagioni ◽  
Giampaolo Versienti ◽  
Elena Andreucci ◽  
Fabio Staderini ◽  
...  

Chemotherapy is still widely used as a coadjutant in gastric cancer when surgery is not possible or in presence of metastasis. During tumor evolution, gatekeeper mutations provide a selective growth advantage to a subpopulation of cancer cells that become resistant to chemotherapy. When this phenomenon happens, patients experience tumor recurrence and treatment failure. Even if many chemoresistance mechanisms are known, such as expression of ATP-binding cassette (ABC) transporters, aldehyde dehydrogenase (ALDH1) activity and activation of peculiar intracellular signaling pathways, a common and universal marker for chemoresistant cancer cells has not been identified yet. In this study we subjected the gastric cancer cell line AGS to chronic exposure of 5-fluorouracil, cisplatin or paclitaxel, thus selecting cell subpopulations showing resistance to the different drugs. Such cells showed biological changes; among them, we observed that the acquired chemoresistance to 5-fluorouracil induced an endothelial-like phenotype and increased the capacity to form vessel-like structures. We identified the upregulation of thymidine phosphorylase (TYMP), which is one of the most commonly reported mutated genes leading to 5-fluorouracil resistance, as the cause of such enhanced vasculogenic ability.


2018 ◽  
Vol 19 (11) ◽  
pp. 3616 ◽  
Author(s):  
Rui Wang ◽  
Xiaoyan Deng ◽  
Chengfu Yuan ◽  
Hongmei Xin ◽  
Geli Liu ◽  
...  

The assembly and maintenance of cilia depend on intraflagellar transport (IFT) proteins, which play an important role in development and homeostasis. IFT80 is a newly defined IFT protein and partial mutation of IFT80 in humans causes diseases such as Jeune asphyxiating thoracic dystrophy (JATD) and short rib polydactyly (SRP) type III, both characterized by abnormal skeletal development. However, the role and mechanism of IFT80 in the invasion of gastric cancer is unknown. We established SGC-7901 and MKN-45 gastric cancer cell lines that stably overexpressed IFT80, as verified by quantitative reverse transcription-PCR, Western blot, and immunofluorescence. Matrix metalloproteinase-9 (MMP9) plays an important role in tumor invasion, and its expression was assessed by quantitative reverse transcription-PCR, Western blotting, and immunofluorescence. The invasion ability of IFT80 on SGC-7901 and MKN-45 cells was examined by the Matrigel invasion assay. The relationship between p75NGFR, and the p75NGFR antagonists, PD90780 and IFT80, were detected by quantitative reverse transcription-PCR and Western blotting. We first detected an IFT80 expression pattern, and found that IFT80 was highly expressed in gastric cancer clinical samples. Overexpression of IFT80 in the gastric cancer cell lines, SGC-7901 and MKN-45, led to lengthening cilia. Additionally, overexpression of IFT80 significantly improved proliferation and invasion, but inhibited apoptosis, in gastric cancer cells. We further found that overexpression of IFT80 increased p75NGFR and MMP9 mRNA and protein expression. Treatment with the p75NGFR antagonist PD90780 inhibited the increased invasion ability resulting from overexpression of IFT80 in SGC-7901 and MKN-45 gastric cancer cells. Thus, these results suggest that IFT80 plays an important role in invasion of gastric cancer through regulating the ift80/p75NGFR/MMP9 signal pathways.


Author(s):  
Nguyen Phu Hung ◽  
Le Thi Thanh Huong ◽  
Nguyen Trung Thanh

According to estimates by the World Health Organization (WHO), in 2018 there were over one million new stomach cancer patients. Vietnam ranks the tenth among the countries with the highest rates of stomach cancer in the world, with the rate of 15.9 cases per 100,000 populations. Research on compounds or drugs that can inhibit cancer cell growth but are less toxic to the body is necessary. In this study, using MTT assays, we have shown that curcumin has ability to inhibit proliferation of stomach cancer cells MKN45. Flow cytometry analysis showed that curcumin increased the percentage of apoptosis cells by 27 - 56% at concentrations of 10 µM - 20 µM and resulted in a typical nuclear morphology of apoptosis. Further, this study showed that curcumin significantly reduced the expression of aldehyde dehydrogenase protein in MKN45 gastric cancer cells. This finding shows that curcumin is a potential therapeutic candidate for gastric cancer cell treatment.


2018 ◽  
Vol 48 (6) ◽  
pp. 2231-2246 ◽  
Author(s):  
Kuan-Fu Liao ◽  
Tsung-Lang Chiu ◽  
Sung-Ying Huang ◽  
Teng-Fu Hsieh ◽  
Shu-Fang Chang ◽  
...  

Background/Aims: Radix Angelica Sinensis (danggui in Chinese) is widely used in traditional chinese medicine (TCM). N-butylidenephthalide (BP), a bioactive compound in danggui, is a potential antitumor agent for various cancer types. However, its clinical effect and mechanism in the treatment of gastric cancer remain undetermined. Methods: The in vivo protective effect of danggui in patients with gastric cancer were validated using data from Taiwan’s National Health Insurance Research Database (NHIRD). The genes induced by BP-treatment were analyzed by whole transcriptome RNA sequencing (RNA-seq) and validated by real-time PCR, western blot and siRNA transfection. The effect of BP on AGS cell migration and invasion was evaluated in transwell assays. The antitumor effects of BP were evaluated in vivo in an AGS xenograft animal model. Results: Danggui users were found to have an increased survival rate when compared with danggui nonusers (log-rank test p = 0.002) . The use of danggui highly associated with decreased mortality (the adjusted hazard ratio (HR) of danggui user was 0.72 [95 % CI, 0.57-0.92] (p = 0.009). The in vitro results showed that BP inhibited gastric cancer cell proliferation, and triggered cellular apoptosis depending on the activation of mitochondrial apoptotic pathway. Using RNA-seq analysis we found that REDD1 was the highest transcript induced by BP in gastric cancer cells. BP induce an increase of REDD1 expression that inhibits mTOR signaling, thus inhibiting gastric cancer growth. We used RNA interference to demonstrate that the knock-down of REDD1 attenuated the BP-induced mTORC1 activation and growth inhibition. BP suppressed the growth of AGS xenografts tumor in vivo. Conclusion: Danggui can prolong the survival rate of gastric cancer patients in Taiwan. BP caused gastric cancer cell death through the activation of mitochondria-intrinsic pathway and induced the REDD1 expression leading to mTOR signal pathway inhibition in gastric cancer cells. BP inhibited the in vivo growth of AGS xenograft tumors. These results may provide the basis for a new therapeutic approach toward the treatment of gastric cancer progression.


2019 ◽  
Vol 17 ◽  
pp. 205873921984553
Author(s):  
Ying Guo ◽  
Li Zhang ◽  
Guangyu Zhou ◽  
Qingjie Ma ◽  
Shi Gao ◽  
...  

This study was designed to investigate the effects of siRNA-mediated silencing of Bmi-1 gene expression on proliferation of AGS gastric cancer cell. siRNA Bmi-1 was transfected into human AGS gastric cancer cells by liposome (as siRNA Bmi-1 group) with negative control (as control group); the expressions of Bmi-1 and apoptosis-related genes like P21, Bax, and Bcl-2 in AGS cells were determined by Western blot method; the apoptosis of AGS cells was detected by flow cytometry double staining and Hoechst staining; and cell cycle was measured by flow cytometry. Compared with the control group, the expression of Bmi-1 in the siRNA Bmi-1 group was significantly decreased ( P < 0.05), the apoptosis rate was increased ( P < 0.05), and cell cycles were arrested at G1 phase (P < 0.05); the expression level of P21 and Bax in cells was significantly up-regulated while that of Bcl-2 down-regulated ( P < 0.05). The down regulation of Bmi-1 can inhibit the proliferation of AGS gastric cancer cell and promote its apoptosis, which takes such effects mainly by up-regulating P21 as well as Bax and down-regulating Bcl-2.


2019 ◽  
Vol 9 (12) ◽  
pp. 1699-1705
Author(s):  
Yuming Luo ◽  
Wei Cao

The present study aimed to investigate the effect of miR-3613 on the biological functions of gastric cancer cell lines. The expression of miR-3613 and SOCS4 in gastric cancer cells were detected by RT-qPCR and western blot. The target genes of miR-3613 were verified with the luciferase reporter system and western blot. The SOCS4 overexpression plasmid was constructed and transfected into gastric cancer cells. To further investigate the function of miR-3613, shRNA targeting miR-3613 and SOCS4 overexpression were transfected into SGC-7901. The growth of cells was detected by CCK-8, then the cell invasion and migration ability were detected by wound healing and transwell. Furthermore, the level of cell cycle was detected by flow cytometry. The expression of cell proliferation, cyclin and migration-related proteins were detected by western blot. The results revealed that the expression of miR-3613 is significantly increased in gastric cancer cells. SOCS4 is one of the target genes of miR-3613. Additionally, interference with miR-3613 promotes cell cycle arrest in gastric cancer cells and reversed the inhibitory effect of miR-3613 on biological function of gastric cells. Collectively, the data demonstrated that miR-3613 regulates gastric cancer cell by targeting SOCS4, which is expected to be an attractive target for the development of new drugs for the treatment of gastric cancer.


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