scholarly journals NUSAP1 Enhances Drug Resistance By Binding to RAD51 through DNA Damage Repair Pathway in Chronic Lymphocytic Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 13-14
Author(s):  
Yang Han ◽  
Ya Zhang ◽  
Xinting Hu ◽  
Xiang Sun ◽  
Xin Wang

Introduction: Enhanced DNA damage repair effect is an important mechanism for drug-resistance in chronic lymphocytic leukemia (CLL). Moreover, the ability of cancer cells to repair under radiation or chemotherapy drug induced DNA damage also serves as one of the mechanisms for therapy resistance. It is reported that nucleolar and spindle associated protein 1 (NUSAP1), a microtubule binding protein, has been involved in DNA damage repair process and plays important roles in the development, progression, and metastasis in several types of cancer. However, its role and mechanism in the development of CLL are still unclear. Methods: Expression levels of NUSAP1 mRNA and protein in CLL cell lines and patient specimens were detected by qRT-PCR and Western blot, and Kaplan-Meier survival curve and overall survival were analyzed by log-rank test. Peripheral blood samples from de novo CLL patients and healthy volunteers were collected with informed consents at the Department of Hematology in Shandong Provincial Hospital Affiliated to Shandong University (SPHASU). Microarray datasets GSE22762 were obtained from Gene Expression Omnibus. With altering NUSAP1 expression by lentivirus-transfected cells in vitro, the effects of NUSAP1 on cell proliferation, apoptosis and cycle were detected by CCK8, Annexin V-PE /7AAD staining and PI/RNase staining respectively. Bioinformatics analysis, luciferase reporter analysis, immunoprecipitation and were applied to discern and examine the relationship between NUSAP1 and its potential targets. Results: According to clinical specimens and bioinformatics analysis, the expression level of NUSAP1 gene in samples of CLL patients was significantly increased than that of healthy donors (P<0.05) (Figure A). Besides, the results indicated that the OS of patients with highly expressed NUSAP1 was significantly worse than in patients with low expression with the statistical analysis database GSE22762. mRNA and protein expression levels of NUSAP1 were significantly higher in CLL cell lines than in PBMCs from healthy donors (Figure C). Our findings indicated that NUSAP1 knockdown notably inhibited cell proliferation when compared with the Scramble group (Figure D). Moreover, the amounts of DNA fragmentation of the apoptotic cells were remarkably increased by NUSAP1 shRNA in MEC-1 and EHEB cells when compared with the Scramble group (Figure E). In addition, after knocking down NUSAP1, MEC-1 and EHEB cells were blocked in G0/G1 phase (Figure F). Moreover, addition to fludarabine or ibrutinib with shNUSAP1 group showed enhanced cytotoxicity in CLL cells (Figure G). The differential genes were analyzed via RNA-seq between Scramble and ShNUSAP1 group. Intriguingly, annotations of gene ontology (GO) analysis indicated that NUSAP1 was closely related to biological processes including cell cycle and response to drug. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that NUSAP1 were enriched in pathways in cancer, DNA replication and cell cycle. Gene set enrichment analysis (GSEA) implicated that NUSAP1 was functionally enriched in DNA replication, cell cycle and proteasome (Figure H). Immunofluorescence showed that NUSAP1 was mainly distributed in the cell nucleus, and the expression level of RAD51 was positively correlated with the change of NUSAP1 expression (Figure I). Surppression of NUSAP1 inhibited the action of proteins in DNA damage repair pathway (Figure J). Through COIP, NUSAP1 was identified to bind with RAD51 and play an important role in DNA damage repair pathway (Figure K). Hence, NUSAP1 participates in the DNA damage repair process and enhances the drug resistance in CLL. Conclusions: This study first demonstrated that the high expression of NUSAP1 in CLL patients is associated with poor prognosis through database analysis and experiments in vitro. Interference of NUSAP1 expression led to a slower CLL cell proliferation and a higher apoptosis rate, meanwhile induced the G1 phase arrest. Collectively, our findings demonstrated that NUSAP1 contributes to DNA damage repairing by binding to RAD51 and enhances drug resistance in CLL. Therefore, NUSAP1 is expected to be a potential target for the treatment of CLL with drug-resistance. Figure 1 Disclosures No relevant conflicts of interest to declare.

2019 ◽  
Vol 316 (3) ◽  
pp. C299-C311 ◽  
Author(s):  
Jing Luo ◽  
Zhong-Zhou Si ◽  
Ting Li ◽  
Jie-Qun Li ◽  
Zhong-Qiang Zhang ◽  
...  

Hepatocellular carcinoma (HCC) is known for its high mortality rate worldwide. Based on intensive studies, microRNA (miRNA) expression functions in tumor suppression. Therefore, we aimed to evaluate the contribution of miR-146a-5p to radiosensitivity in HCC through the activation of the DNA damage repair pathway by binding to replication protein A3 (RPA3). First, the limma package of R was performed to differentially analyze HCC expression chip, and regulative miRNA of RPA3 was predicted. Expression of miR-146a-5p, RPA3, and DNA damage repair pathway-related factors in tissues and cells was determined. The effects of radiotherapy on the expression of miR-146a-5p and RPA3 as well as on cell radiosensitivity, proliferation, cell cycle, and apoptosis were also assessed. The results showed that there exists a close correlation between miR-146a and the radiotherapy effect on HCC progression through regulation of RPA3 and the DNA repair pathway. The positive rate of ATM, pCHK2, and Rad51 in HCC tissues was higher when compared with that of the paracancerous tissues. SMMC-7721 and HepG2 cell proliferation were significantly inhibited following 8 Gy 6Mv dose. MiR-146a-5p restrained the expression of RPA3 and promoted the expression of relative genes associated with the DNA repair pathway. In addition, miR-146a-5p overexpression suppresses cell proliferation and enhances radiosensitivity and cell apoptosis in HCC cells. In conclusion, the present study revealed that miR-146a-5p could lead to the restriction of proliferation and the promotion of radiosensitivity and apoptosis in HCC cells through activation of DNA repair pathway and inhibition of RPA3.


2020 ◽  
Author(s):  
Kwok Kin Lee ◽  
Yanzhou Zhang ◽  
Roberto Tirado- Magallanes ◽  
Deepa Rajagopalan ◽  
Shreshtha Sailesh Bhatia ◽  
...  

AbstractTIP60, a lysine acetyltransferase and H2AZ, a histone H2A variant are involved in transcription and DNA repair. Recent studies suggest that H2AZ acetylation is dependent on TIP60. Here, we show that TIP60 acetylates both isoforms of H2AZ in vitro and in cells. Utilizing ChIP-seq and RNA-seq to identify the genes regulated by TIP60-dependent acetylation of H2AZ, we find that TIP60-dependent acetylation of H2AZ correlates with the expression of genes involved in DNA damage repair, amongst several other pathways. In line with this, TIP60-depleted cells exhibit increased sensitivity to the DNA damage-inducing drug doxorubicin. Restoring the expression level of RAD51, one of the genes involved in the DNA damage repair pathway, partially rescues the doxorubicin sensitivity due to TIP60 depletion. Overall, our study uncovers a role for TIP60 in regulating doxorubicin-induced DNA damage sensitivity in a manner dependent on RAD51 transcription.


2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Nan Huang ◽  
Chang Xu ◽  
Liang Deng ◽  
Xue Li ◽  
Zhixuan Bian ◽  
...  

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.


2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Jing Song ◽  
Ping Hong ◽  
Chengeng Liu ◽  
Yueqi Zhang ◽  
Jinling Wang ◽  
...  

2016 ◽  
Vol 24 (10) ◽  
pp. 1501-1505 ◽  
Author(s):  
Clara Esteban-Jurado ◽  
◽  
Sebastià Franch-Expósito ◽  
Jenifer Muñoz ◽  
Teresa Ocaña ◽  
...  

2014 ◽  
Vol 13 (4) ◽  
pp. 10269-10278 ◽  
Author(s):  
Q.Y. Yang ◽  
J.H. Li ◽  
Q.Y. Wang ◽  
Y. Wu ◽  
J.L. Qin ◽  
...  

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