Análise de impacto orçamentário dos inibidores da PARP no tratamento do carcinoma de ovário avançado a partir de evidências de mundo real sob a perspectiva de um hospital federal referência em oncologia / Budget impact analysis of PARP inhibitors in the treatment of advanced ovarian cancer from on real-world evidence the perspective of a federal hospital reference in oncology

Objetivo: Avaliar o impacto orçamentário do tratamento com iPARP como primeira linha de manutenção, comparado ao tratamento-padrão a partir de evidências de mundo real sob a perspectiva de um hospital público referência em oncologia no Rio de Janeiro. Métodos: Foi aplicada uma análise de impacto orçamentário para estimar a introdução das tecnologias iPARP, olaparibe e niraparibe, em comparação com o cenário referência, utilizando dados de eficácia e evidências de mundo real, e considerando os custos globais de tratamento da doença em cinco anos. Este estudo foi aprovado pelo Comitê de Ética em Pesquisa, CAAE: 95157018.9.0000.5274. Resultados: A análise demonstrou que o cenário referência apresentou um impacto orçamentário no valor de R$ 3.578.768,04 em cinco anos. No cenário alternativo, o custo incremental do olaparibe chegou a ser 23,8% maior, comparado ao niraparibe, atingindo um custo de R$ 23.736.459,20 versus R$ 18.076.951,81, respectivamente. Os parâmetros que apresentaram maior impacto nas análises para a tecnologia olaparibe foram a difusão da tecnologia e o preço do medicamento. Contudo, para o niraparibe, os parâmetros de maior impacto foram a duração do tratamento, a difusão da tecnologia e a dose utilizada, demonstrando maior suscetibilidade de variação. Conclusão: Os iPARP no tratamento de pacientes com carcinoma de ovário avançado, apesar de apresentarem custo incremental de aproximadamente R$ 23 milhões em cinco anos, apontam para uma potencial redução de custos associados à progressão da doença.

Objective: Assess the budgetary impact of treatment with iPARP as a first line of maintenance, compared to standard treatment based on real-world evidence from the perspective of a public hospital reference in oncology at Rio de Janeiro. Methods: A budget impact analysis was applied to estimate the introduction of iPARP, olaparib and niraparib technologies, compared to the reference scenario, using efficacy data and real-world evidence, and considering the global costs of treating the disease in five years. This study was approved by the Research Ethics Committee, CAAE: 95157018.9.0000.5274. Results: The analysis showed that the reference scenario presented a budgetary impact of R$ 3,578,768.04 in five years. In the alternative scenario, the incremental cost of olaparib reached 23.8% higher compared to niraparib, reaching a cost of R$ 23,736,459.20 versus R$ 18,076,951.81, respectively. The parameters that had the greatest impact on the analyzes for the olaparib technology were technology diffusion and drug price. However, for niraparib, the parameters with the greatest impact were the duration of treatment, the diffusion of the technology and the dose used, demonstrating greater susceptibility to variation. Conclusion: iPARP in the treatment of patients with advanced ovarian carcinoma, despite having an incremental cost of approximately R$ 23 million in five years, point to a potential reduction in costs associated with disease progression.

Analysis of the Factors Affecting the Configuration of the Anti-parallel G-quadruplex Formed by 22-nt Telomere RNA Fragments / 中国生物化学与分子生物学报

G-quadruplexes with different conformations often exhibit different binding abilities to proteins and play different physiological functions. It is of great significance to analyze the factors affecting the configuration of G-quadruplex to explore its physiological function. Different from DNA, RNA sequences have shown parallel G-quadruplex structures in previous reports. However, we found that the only RNA sequence, the 22-nt telomere RNA fragment (ORN-N, A

Chinese expert consensus on drug interaction management of poly ADP-ribose polymerase inhibitors / 中华肿瘤杂志

Poly ADP-ribose polymerase inhibitors (PARPi), which approved in recent years, are recommended for ovarian cancer, breast cancer, pancreatic cancer, prostate cancer and other cancers by The National Comprehensive Cancer Network (NCCN) and Chinese Society of Clinical Oncology (CSCO) guidelines. Because most of PARPi are metabolized by cytochrome P450 enzyme system, there are extensive interactions with other drugs commonly used in cancer patients. By setting up a consensus working group including pharmaceutical experts, clinical experts and methodology experts, this paper forms a consensus according to the following steps: determine clinical problems, data retrieval and evaluation, Delphi method to form recommendations, finally formation expert opinion on PARPi interaction management. This paper will provide practical reference for clinical medical staff.

Protective role and mechanism of human umbilical cord mesenchymal stem cell-derived exosome in renal ischemia-reperfusion injury / 器官移植

Objective To investigate the protective effect of human umbilical cord mesenchymal stem cell-derived exosome (hucMSC-Exo) on renal ischemia-reperfusion injury (IRI), and to clarify the critical role and regulating mechanism of transient receptor potential canonical (TRPC) 6/poly adenosine-diphosphate-ribose polymerase (PARP) 1 signaling pathway during this process. Methods The hucMSC-Exo was extracted by ultracentrifugation, and identified by transmission electron microscope (TEM), nanoparticle tracing analysis and Western blot. SD rats were randomly divided into the sham operation group (group S), sham operation+TRPC6 inhibitor SKF96365 group (group SS), renal IRI group (group IRI), exosome treatment group (group EXO) and exosome +TRPC6 inhibitor SKF96365 group (group ES), with 6 rats in each group. Serum creatinine and blood urea nitrogen levels were detected. Pathological changes of renal tissues were observed by hematoxylin-eosin (HE) staining and Paller score was calculated. The expression levels of key molecules of necroptosis in rat renal tissues, including receptor-interacting protein kinase (RIPK)1, RIPK3 and mixed-lineage kinase domain-like protein (MLKL), TRPC6 and PARP1, were detected by Western blot. Results Typical saucer-like structure was observed under TEM. Nanoparticle tracing analysis showed that the average diameter of the extracted substance was 125.9 nm. Western blot revealed that the surface markers of CD9, CD63 and CD81 were positively expressed, confirmed that the extracted substance was exosome. Compared with group S, the serum creatinine and blood urea nitrogen levels were up-regulated, the pathological damage of renal tissues was worsened, Paller score was elevated, the relative expression levels of TRPC6 and PARP1 proteins were down-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were up-regulated in group IRI (all P < 0.05). Compared with group IRI, the serum creatinine and blood urea nitrogen levels were down-regulated, the pathological damage of renal tissues was mitigated, Paller score was decreased, the relative expression levels of TRPC6 and PARP1 proteins were up-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were down-regulated in group EXO (all P < 0.05). Compared with group EXO, the serum creatinine and blood urea nitrogen levels were up-regulated, the pathological damage of renal tissues was aggravated, Paller score was increased, the relative expression levels of TRPC6 and PARP1 proteins were down-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were up-regulated in group ES (all P < 0.05). Conclusions hucMSC-Exo may alleviate the necroptosis induced by renal IRI in rat models, which is related to the activation of TRPC6/PARP1 signaling pathway.

Guidance on the management of adverse reactions induced by poly(ADP-ribose) polymerase inhibitors / 浙江大学学报·医学版

The common adverse reactions caused by poly (ADP-ribose) polymerase (PARP) inhibitors include hematological toxicity, gastrointestinal toxicity and fatigue. The main prevention and treatment of hematological toxicity include: regular blood tests, referral to hematology department when routine treatment is ineffective, and being alert of myelodysplastic syndrome/acute myeloid leukemia. The key points to deal with gastrointestinal toxicity include: taking medicine at the right time, light diet, appropriate amount of drinking water, timely symptomatic treatment, prevention of expected nausea and vomiting, and so on. For fatigue, full assessment should be completed before treatment because the causes of fatigue are various; the management includes massage therapy, psychosocial interventions and drugs such as methylphenidate and Panax quinquefolius according to the severity. In addition, niraparib and fluzoparib can cause hypertension, hypertensive crisis and palpitation. Blood pressure and heart rate monitoring, timely symptomatic treatment, and multidisciplinary consultation should be taken if necessary. When cough and dyspnea occur, high resolution CT and bronchoscopy should be performed to exclude pneumonia. If necessary, PARP inhibitors should be stopped, and glucocorticoid and antimicrobial therapy should be given. Finally, more attention should be paid to drug interaction management, patient self-management and regular monitoring to minimize the risk and harm of adverse reactions of PARP inhibitors.

Inhibitory Effect of Paeonol on Vascular Smooth Muscle Cell Senescence by Reducing SIRT6/PARP1-mediated DNA Damage / 中国实验方剂学杂志

ObjectiveTo investigate whether the effects of paeonol （Pae） on angiotensin Ⅱ （AngⅡ）-induced senescence in vascular smooth muscle cells （VSMCs） were related to angiotensinogen of silencing regulatory information factor 6 （SIRT6）/adenosine diphosphate ribose polymerase 1 （PARP1） signaling pathway in VSMCs. MethodThe model of VSMC-stress aging induced by AngⅡ （100 nmol·L-1） was established. The rats were divided into normal group， model group， low， medium， and high-concentration Pae groups （30， 60， 120 μmol·L-1）. The positive rate of cell senescence was detected by SA-β-Gal staining， the ability of cell proliferation was detected by the cell counting kit-8 （CCK-8） method， the expression of SIRT6， PARP1， p16， p21， p53， proliferating cell nuclear antigen （PCNA）， deoxyribonucleic acid （DNA）-damaged protein γ-H2AX was detected by Western blot， and VSMC proliferation was detected by EdU staining. The silenced VSMCs were prepared by siRNA-SIRT6 transfection， and the protein expressions of SIRT6， PARP1， p16， and γ-H2AX in VSMCs silenced by SIRT6 were observed. ResultThe results of SA-β-Gal staining showed that the senescence positive rate of SA-β-Gal staining in the model group was higher than that in the normal group （P<0.01）， and the positive rate of SA-β-Gal staining in the Pae group was significantly lower than that in the model group （P<0.05， P<0.01）. The results of Western blot showed that as compared with the normal group， the expression of PCNA， SIRT6， and PARP1 in the model group was down-regulated， and the expression of aging-related proteins p16， p21， p53， and γ-H2AX was up-regulated in the model group （P<0.05， P<0.01）. Compared with the model group， Pae promoted the protein expression of PCNA， SIRT6， and PARP1 and inhibited the protein expression of p16， p21， p53， and γ-H2AX in a dose-dependent manner （P<0.05， P<0.01）. The results of EdU staining showed that the number of EdU positive cells in the model group was lower than that in the normal group （P<0.01）， and the number of EdU positive cells in Pae groups was significantly higher than that in the model group （P<0.05， P<0.01）. After SIRT6 silencing， the effects of Pae on promoting SIRT6 and PARP1 and inhibiting P16 were reversed （P<0.05， P<0.01）. In addition， the addition of SIRT6 inhibitor （IN-1） promoted the occurrence of cell senescence induced by AngⅡ （P<0.05， P<0.01）. ConclusionPae can effectively inhibit the aging of VSMCs， and its mechanism may be related to the regulation of SIRT6/PARP1 signal pathway.

Research progress on treatment strategies for related diseases based on Parthanatos / 中国生物制品学杂志

@#Parthanatos is a form of programmed cell death,which is also known as poly(ADP-ribose)polymerase 1(PARP1)-mediated apoptosis-inducing factor(AIF)and macrophage migration inhibitory factor(MIF)-dependent cell death according to its molecular mechanism. Parthanatos is the main cause of a variety of neurodegenerative diseases,such as Parkinson's disease(PD),Alzheimer's disease(AD),motor neuron disease,and is also involved in the pathogenesis of some tumors,such as lung cancer and breast cancer. Therefore,a thorough understanding of the molecular mechanism of Parthanatos is crucial for the therapeutic strategies of related diseases. In recent years,studies have found that effective regulation of the occurrence of Parthanatos by regulating the key proteins PARP1,AIF and MIF is expected to become a therapeutic target for many diseases. Based on the specific molecular mechanism of Parthanatos,this paper reviewed the research progress of therapeutic strategies for related diseases from the aspects of inhibiting and promoting Parthanatos.

Progress of poly (ADP-ribose) polymerase inhibitor in advanced ovarian cancer / 肿瘤研究与临床

At present, ovarian cancer is one of the main diseases threatening women's life and health. The mortality ranks first among female reproductive system malignant tumors. Due to the hidden onset, more than 75% of them are at advanced stage once diagnosed. Advanced ovarian cancer is characterized with the Federation International of Gynecology and Obstetrics (FIGO) stage Ⅲ-Ⅳ, very poor prognosis and the 5-year survival rate less than 50%. In recent years, the exploration of maintenance treatment of ovarian cancer is in full swing. A large number of studies show that poly (ADP-ribose) polymerase (PARP) inhibitors are effective in patients with advanced ovarian cancer. Therefore, PARP inhibitors have gradually become an important part for treatment of ovarian cancer, and the indications have also been concerned by clinicians. This paper reviews the application of PARP inhibitors in advanced ovarian cancer.

Research progress on the efficacy and safety of PARP inhibitors in mCRPC / 中华泌尿外科杂志

Poly ADP-ribose polymerase (PARP) inhibitors are novel agents for the treatment of metastatic castration-resistant prostate cancer (mCRPC) in recent years, and a variety of PARP inhibitors have been reported with clinical evidence for the beneficial. Although these drugs are actually of attributes with pharmacological similarities, due to the discrepancies in the molecular structure and pharmacodynamics, the respective efficacy and safety from clinical circumstances are quite varied. While it comes to the best clinical determination, the optimization for regimen is important on the basis of clinical exhaustiveness for the reports, in addition the laboratory examination for mCRPC, and either the tumorous genetic benchmark are necessarily being calculated.

Effects of niraparib on the radiosensitivity of human esophageal cancer cells and its mechanism / 中华放射肿瘤学杂志

Objective:To evaluate the effect of niraparib, the poly (ADP-ribose) polymerase (PARP) inhibitor, on the radiosensitivity of esophageal squamous cell carcinoma (ESCC) and to preliminarily investigate its mechanism.Methods:Human esophageal squamous cell carcinoma cells ECA-109 and KYSE-150 were divided into the control, niraparib, single irradiation, combined (niraparib+irradiation) groups. Cell proliferation was measured by CCK-8 assay. The changes of cell survival rate were detected by colony formation assay. The changes of cell cycle and apoptosis were analyzed by flow cytometry. The number of γH2AX foci was detected by immunofluorescence, and the expression levels of PARP-1, cleaved-PARP, RAD51, mitogen-activated protein kinase (MAPK) [extracellular signal-regulated kinase 1 and 2 (ERK1/2) ] and p-MAPK (ERK1/2) proteins were determined by Western blot. All data were expressed as Mean±SD. Data between two groups conforming to normal distribution through the normality test were subject to independent sample t-test and multiple groups were analyzed using one-way ANOVA. Results:In human ESCC cells ECA-109 and KYSE-150, the proliferation of ESCC cells was significantly inhibited by niraparib combined with irradiation, and the values of average lethal dose (D 0), quasi-threshould dose(D q), survival fraction after 2 Gy irradiation (SF 2) in the combined group were decreased compared with those in the single irradiation group. The effect of irradiation alone on apoptosis of ECA-109 and KYSE-150 cells was limited. Compared to single irradiation group, irradiation combined with niraparib further increased the apoptosis rate in ESCC cells ( P=0.015, P=0.006). In ECA-109 cells, G 2/M phase arrest was significantly increased in combined group compared with irradiation alone group ( P<0.001). In ECA-109 cells, the number of γH2AX foci in combined group was higher than that in the single irradiation group after 2 h, and showed a significantly slower decay of γH2AX foci ( P<0.001). Moreover, niraparib combined with irradiation enhanced the radiation-induced cleavage of PARP-1 and down-regulated the expression of Rad51 and p-MAPK(ERK1/2). Conclusion:Niraparib can increase the radiosensitivity of esophageal cancer cells by inhibiting cell proliferation, promoting cell apoptosis, inhibiting the repair of DNA damage and regulating the MARK-ERK signaling pathway.

Research progress on the involvement of poly (ADP-ribose) polymerase-1-dependent cell death in ischemia-reperfusion injury / 中国医师杂志

Ischemia reperfusion injury (IRI) of organs is a major challenge for clinicians, but the mechanism is still not elucidated, and the clinical treatment effect is still unsatisfactory. PARP-1-dependent cell death (parthanatos) is a non-apototic programmed cell death pathway involved in the development of the occurrence of IRI of organs. At the same time, parthanatos is also a multi-step pathway. There are many molecules in the parthanatos cascade that can be exploited to create therapeutic interventions for IRI, including PARP1, apoptosis inducing factor (AIF), and macrophage migration inhibitory factor (MIF). These critical molecules are involved in DNA damage, energy depletion and homeostasis imbalance. Therefore, these molecular signals in the parthanatos cascade represent promising therapeutic targets for the treatment of IRI. In the following, we will elaborate on the mechanisms and molecular characteristics of the parthanatos pathway and the relation between parthanatos pathway and IRI of vital organs. It aims to explore the posibility of IRI mechanism research and clinical treatment and to provide new ideas for clinicians and researchers.

Progress of PARP inhibitors in targeted therapy of small cell lung cancer / 国际肿瘤学杂志

Small cell lung cancer (SCLC) is a rapidly developing malignant tumor, which is highly heterogeneous and prone to drug resistance, and the prognosis is usually poor. Poly ADP-ribose polymerase (PARP) inhibitors target the DNA damage response pathway, preventing DNA repair, thereby exerting anti-tumor effects. Currently, PARP inhibitors are used as monotherapy or in combination with DNA-damaging agents or immune checkpoint inhibitors in the treatment of SCLC. Although the current research results are limited, it can be seen that PARP inhibitors may be a breakthrough in the targeted therapy of SCLC.

Screening of a Small Molecule Compound Library Identifies Potential Drugs that Synergize with PARP Inhibitors against Ovarian Cancer Cells / 中国生物化学与分子生物学报

PARP inhibitors are a new class of drugs that target cancer cells with defective DNA repair. Early trials have shown that PARP inhibitors have achieved satisfactory results, but the mechanism of resistance after drug treatment has not been fully revealed. Therefore, it is necessary to find more targeted drugs in combination with PARP inhibitors to kill tumor cells. In this paper, several potential drugs that can synergistically kill ovarian cancer cells with PARP inhibitors were identified based on the combined drug screening of 379 small molecule compound libraries and PARP inhibitor Niraparib through cell proliferation experiments, colony-formation survival experiments and immunofluorescence staining experiments. The results showed that there are eight small molecule compounds with good combination effects, including two small molecule inhibitors STF-118804 and Disulfiram that have been reported to have combined effects with PARP inhibitors. We selected GW441756, an inhibitor of tropomyosin receptor kinase A (TrKA), to verify a variety of tumor cells and explore the preliminary mechanism. The combined therapeutic effects of the Niraparib and the TrKA inhibitor increased the sensitivity of tumor cells to PARP inhibitors (P < 0. 05). Mechanistically, the number of γH2AX foci in the combined treatment group was significantly increased (P<0. 05), indicating that the TrKA inhibitor hindered the DNA damage repair ability. Moreover, combination therapy significantly reduced the formation of RAD51 foci (P<0. 05), a marker of homologous recombination repair (HRR), suggesting that TrKA inhibitors may inhibit DNA damage repair by inhibiting HRR efficiency. Overall, these results suggest that TrKA inhibitor can be used as a potential drug to kill ovarian cancer cells in combination with PARP inhibitors.

Function of PARP1 and Mechanism of Action and Drug Resistance of PARP Inhibitors / 中国生物化学与分子生物学报

Poly ADP⁃ribose polymerase 1 (PARP1) is an important modification enzyme in cells. Its most well⁃known function is to recruit multiple DNA damage repair effector proteins through its own PARylation, such as XRCC1, to participate in DNA single and double strand damage repair. In addition, PARP1 can also provide favorable conditions for DNA damage repair and maintain genomic stability by promoting replication fork stall and nucleosome depolymerization. In recent years, in addition to the function of DNA damage repair, PARP1 has also been found to play an important role in cell apoptosis, autophagy and inflammatory pathways, which is closely related to the occurrence and development of neurodegenerative diseases. PARP inhibitor (PARPi) is an antitumor drug that targets PARP1 and works together with a homologous recombination (HR) deficient phenotype to produce a synthetic lethality. The drug can trap PARP1 and inhibit its activity. On the one hand, it directly interferes with the DNA damage repair pathway that PARP1 participates in; and on the other hand, it also inhibits the selection of PARP1⁃mediated DNA damage repair pathway and replication fork stall, making the cell genome instable. However, tumor cells are often found to be insensitive to PARPi in clinical treatment. Drug resistance of tumor cells to PARPi is highly correlated with mutations of their own genes, which respectively act on cell HR repair pathway, PARP1 circulation pathway, replication fork stability and active drug efflux, etc. Identifying specific mutation sites in drug⁃resistant tumor cells will provide help for clinical treatment. The purpose of this review is to give a description about the functions of PARP1, and focus on the mechanism of action of PARPi, the mutated genes related to drug resistance and their drug resistance mechanism, therefore to deepen the understanding of PARP1 mediated DNA damage repair pathway in cells, and provide new ideas for future clinical treatment.

Research progress of NF-κB signaling pathway in kidney ischemia-reperfusion injury / 器官移植

Kidney ischemia-reperfusion injury (IRI) is the major cause of poor prognosis after kidney transplantation and partial nephrectomy. Besides, it is also a critical pathophysiological process of acute kidney injury. Consequently, the prevention and treatment of kidney IRI are of significance to improve clinical prognosis of recipients undergoing kidney transplantation. However, the mechanism underlying IRI is complex, and the exact mechanism remains elusive. Inflammation, as one of the main pathogenesis of IRI, plays a significant role in IRI-induced kidney injury. Nuclear factor (NF)-κB, as a rapid response transcription factor, has been proven to be involved in the regulation of inflammation during kidney IRI. Therefore, in this article, the structure of NF-κB, the activation pattern of NF-κB signaling pathway, the regulatory mechanisms of NF-κB upstream and downstream signaling pathways in kidney IRI were reviewed, and the role of NF-κB signaling pathway in kidney IRI was investigated, aiming to provide novel clinical ideas for the prevention and treatment of kidney IRI.

Progress in preclinical study of combination of PARP inhibitors against tumor / 中国药房

Poly（ADP-ribose）polymerase（PARP）is a kind of DNA damage repair enzyme. PARP inhibitors include Olaparib （AZD2281），Niraparib（MK-4827），Rucaparib，Veliparib（ABT-888），Fluzoparib and Talazoparib （BMN-673），etc. This article reviews the preclinical research on the combined application of PARP inhibitors against tumor by searching the relevant literatures. Through the synthetic lethal mode ，PARP inhibitors have a strong killing effect on tumor cells with homologous recombination repair defects. However ，for tumor cells with intact DNA damage repair function ，PARP inhibitors often need to be combined with radiotherapy or other drugs to play a role. Combined application drugs include antiangiogenic drugs ，heat shock protein 90 inhibitors，cyclin-dependent kinase 12 inhibitors，immune checkpoint inhibitors ，histone deacetylase inhibitors ，etc. The combined application of PARP inhibitors is expected to enhance the efficacy of anti-tumor drugs and achieve the goals of sensitization ， synergism and reversal of drug resistance ，which is worthy of further in-depth research and exploration of new combined treatment schemes.

Expression level and clinical significance of PARP14 in thyroid carcinoma / 国际生物医学工程杂志

Objective:To investigate the expression level of poly ADP ribose polymerase 14(PARP14) in thyroid cancer and its relationship with the clinicopathologic characteristics of the patient with thyroid cancer and evaluate the role of PARP14 in the progression of thyroid cancer.Methods:The gene expression interaction analysis (GEPIA) database was used to analyze the expression of PARP14 in normal thyroid tissue and thyroid cancer tissue and its relationship with disease-free survival of patients. The expression of PARP14 in thyroid cancer tissue and adjacent tissues of the patient with thyroid cancer was evaluated by immunohistochemistry. According to the staining intensity, the patients were divided into the high expression group and the low expression group, and the correlation between the expression of PARP14 and clinical pathological characteristics was analyzed. The effect of PARP14 on the proliferation of thyroid cancer cells was investigated by clone formation testing and MTT testing.Results:The results of bioinformatics analysis and immunohistochemistry showed that PARP14 was overexpressed in thyroid cancer tissue, and the disease-free survival rate of the patient with high expression was lower. The expression level of PARP14 was correlated with tumor stage and intrathyroidal spread (all P<0.05). The results of the clonogenic assay and the MTT assay showed that the expression of KIF4A could promote the proliferation of thyroid cancer cells ( P<0.05). Conclusions:PARP14 is highly expressed in thyroid cancer and is related to the clinicopathological characteristics of patients, suggesting that it may be a therapeutic target for thyroid cancer.

PARP-1 participates in regulation of cell cycle signaling in the hydroquinone-induced TK6 malignant transformation / 中国职业医学

@#To investigate the expression of polyadenosine diphospho-ribose polymerase 1 (PARP-1) and p16/ retinoblastoma (Rb) protein in hydroquinone (HQ)-induced TK6 cells and their regulatory mechanisms. Methods According to the 2×2 factorial design model, TK6 cells were divided into PBS-TK6 group and HQ-TK6 group based on HQ exposure, and then sub-divided into non-DOX intervention subgroup and DOX intervention subgroup based on DOX intervention, a total of four groups. The PBS-TK6 group was treated with phosphate buffer saline, and the HQ-TK6 group was treated with HQ at a final concentration of 20.0 μmol/L. The non-DOX intervention subgroup was added with 0.05% dimethyl sulfoxide; and the DOX intervention subgroup was added with PARP-1 agonist DOX at a final concentration of 0.5 μmol/L. The distribution of cell cycle was detected by flow cytometry. The protein expression of p16/Rb, cyclin D1 (cyclinD1), multifunctional protein E2 transcription factor 1 (E2F1), Rb, and p-Rb were detected by Western blot, and the level of p16 ribosylation was detected by immunofluorescence and immunoprecipitation. Results Compared with the PBS-TK6 group, the cell cycle distribution percentage in G0/G1 phase and the relative expression levels of p16 proteins were decreased in the cells of the HQ-TK6 group (all P<0.05). The cell cycle distribution percentage in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were up-regulated (all P<0.05). Compared with the non-DOX intervention group, the cell cycle distribution percentage in G0/G1 and G2/M phases and the relative expression level of p16 protein increased in the DOX intervention group (all P<0.05). The percentage of cells in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were down-regulated (all P< 0.05). The results of interaction effect analysis showed that compared with the non-DOX PBS-TK6 cells, the relative expression levels of Rb and E2F1 protein in the DOX PBS-TK6 cells intervention group were down-regulated (all P<0.05). The relative expression level of Rb protein in non-DOX HQ-TK6 cell group was down-regulated (P<0.05), and the relative expression of E2F1 protein was up-regulated (P<0.05). Compared with DOX PBS-TK6 cell group, the relative expression level of Rb protein in DOX HQ-TK6 cell group was down-regulated and that of E2F1 protein was up-regulated (all P<0.05). Compared with the non-DOX HQ-TK6 cell group, the relative expression level of Rb protein in the DOX HQ-TK6 cell group was up-regulated and that of E2F1 protein was down-regulated (all P<0.05). Conclusion PARP-1 participates in cell cycle regulation by regulating the p16/Rb signaling pathway in TK6 cells.

Expression of DNA damage-binding protein 1 in hepatocellular carcinoma tissues and its effect on homologous recombination repair and targeted killing in SMMC-7721 cells / 肿瘤研究与临床

Objective:To investigate the expression of DNA damage repair factor DNA damage-binding protein 1 (DDB1) in hepatocellular carcinoma tissues, and the effect of DDB1 gene silencing on DNA repair and targeted killing in human hepatocellular carcinoma SMMC-7721 cells.Methods:The UALCAN platform was used to perform bioinformatics analysis on the expression of DDB1 in hepatocellular carcinoma tissues (371 cases) and paracancerous tissues (50 cases) in The Cancer Genome Atlas (TCGA) database and the correlation of DDB1 expression with the overall survival of liver cancer patients were analyzed by bioinformatics using the UALCAN platform. SMMC-7721 cells were transfected with small interfering RNA (siRNA) targeting DDB1 and negative control siRNA, which were DDB1 silencing group and negative control group, respectively. X-ray irradiation induced exogenous DNA double strand break (DSB) damage in the two groups of cells. Immunofluorescence staining (γH2AX was used for assessing cellular DSB damage, RPA32s33 and Rad51 were used for assessing homologous recombination repair) and Western blotting (were used to detect the level of RPA32s33 protein) were used to analyze the effect of DDB1 gene silencing on DSB damage repair. Sister chromosome exchange (SCE) experiment was used to analyze the frequency of SCE of homologous recombination of cells in DDB1 silencing group and negative control group. Tetramethylazozolium salt (MTT) method was used to analyze the killing effect of PARP inhibitor olapani (10 μmol/L), cisplatin (1 μg/ml) and olapani combined with cisplatin on SMMC-7721 cells in DDB1 silencing group and negative control group.Results:Bioinformatics analysis showed that the level of DDB1 mRNA in liver cancer tissues was higher than that in paracancerous tissues ( P < 0.001), and the overall survival of patients with high expression of DDB1 was worse than that of patients with low expression of DDB1 ( P = 0.029). When cultured for 4 hours after X-ray irradiation, the number of γH2AX foci in cells of the negative control group had mostly disappeared, and there were still more cells in DDB1 silencing group [(5.1±2.0) per cell vs. (13.4±2.0) per cell, t = -5.08, P = 0.007]. When cultured for 4 hours after X-ray irradiation, the number of RPA32s33 foci in the negative control group [(30.8±5.0) per cell vs. (13.2±1.6) per cell] and the number of Rad51 foci [(19.5±1.8) per cell vs. (8.3±3.3) per cell] were higher than those in the DDB1 silencing group, and the differences between the two groups were statistically significant (both P < 0.01). The frequency of SCE in the negative control group was higher than that in the DDB1 silencing group [(21.2±3.0)% vs. (11.2±1.6)%, t = 5.07, P = 0.007]. MTT assay showed that after olaparib treatment, the survival rate of cells in the DDB1 silencing group was lower than that in the negative control group [(40.3±3.6)% vs. (79.8±1.3)%, t = 17.94, P < 0.001]. When treated with olapani combined with cisplatin, the survival rate of cells in the two groups further decreased, and the survival rate of cells in the DDB1 silencing group was lower than that in the negative control group [(10.2±2.8)% vs. (29.6±3.4)%, t = 7.72, P = 0.002]. When treated with cisplatin alone, there was no significant difference in cell survival between DDB1 silencing group and negative control group [(41.9±5.1)% vs. (49.8±3.3)%, t = 2.71, P = 0.054]. Conclusions:The high expression of DDB1 in hepatocellular carcinoma tissues may be an important factor in the treatment resistance and poor prognosis of hepatocellular carcinoma. Knockdown of DDB1 gene expression can promote the sensitivity of SMMC-7721 cells to PARP inhibitors, and its mechanism may be related to the homologous recombination repair defect of SMMC-7721 cells caused by DDB1 silencing.

Progress of drug resistance mechanism of poly adenosine diphosphate ribose polymerase inhibitors and the combined medication in patients with ovarian cancer / 肿瘤研究与临床

Ovarian cancer seriously threats women's health. The emergence of poly adenosine diphosphate ribose polymerase inhibitor (PARPi) has broken the barrier for ovarian cancer treatment. PARPi has been widely used and along with it comes the problem of drug resistance. Fully understanding the drug resistance mechanism of PARPi is expected to be an important way to reverse PARPi resistance. The combination of PARPi and other drugs for ovarian cancer may expand the benefits of patients using PARPi. This article reviews the drug resistance mechanism of PARPi and combined medication.