Treatment of palbociclib in hormone receptor positive breast cancer: a real-world study and efficacy prediction model / 中华肿瘤杂志

Objective: To summarize the clinical use of palbociclib and evaluate its efficacy and safety in hormone-receptor (HR)-positive advanced breast cancer patients. Methods: We retrospectively analyzed data from 66 HR-positive metastatic breast cancer patients treated with palbociclib and endocrine therapy at the Department of Oncology in the First Affiliated Hospital with Nanjing Medical University between 2018 and 2020. We evaluated the factors affecting the efficacy of palbociclib using Kaplan-Meier method and Log-rank test for survival analysis and Cox regressions for multivariate analysis. Nomogram model was built for predicting prognosis among HR-positive breast cancer patients who received palbociclib. Concordance index (C-index) and calibration curve were used for internal validation to assess the predictive ability and conformity of the model. Results: Of the 66 patients treated with palbociclib, 33.3%(22), 42.4%(28) and 24.2%(16) patients were treated without endocrine therapy, first-line endocrine therapy, second-line or above endocrine therapy after recurrence, respectively. 36.4%(24) patients had hepatic metastasis, 16.7% (11) patients were sensitive to previous endocrine therapy, 27.3%(18/66) patients had primary resistance to endocrine therapy, while 56.1% (37) patients had secondary resistance to endocrine therapy. The overall response rate was 14.3% (95% CI: 6.7%, 25.4%) and clinical benefit rate was 58.7% (95% CI: 45.6%, 71.0%). Better clinical outcomes were associated with non-hepatic metastasis (P=0.001), sensitive/secondary resistant to previous endocrine therapy (P=0.004), no or only one line of chemotherapy for metastatic breast cancer (P=0.004), recent pathological confirmation of immunohistochemical analysis (P=0.025). Hepatic metastasis (P=0.005) and primary resistance to endocrine therapy (P=0.016) were the independent risk factors of progression free survival. The C-index of predictive probability for the nomogram constructed from the patient clinical characteristics (whether liver metastasis, whether primary endocrine resistance, lines of chemotherapy after metastasis, lines of endocrine therapy, number of metastatic sites, and time to last immunohistochemistry) to predict the progression-free survival at 6 and 12 months for patients was 69.7% and 72.1%, respectively. The most common adverse events were hematologic toxicities. Conclusions: Our report indicates that palbociclib combined with endocrine therapy for HR-positive recurrent metastatic breast cancer is effective and safe; patients with hepatic metastases and primary resistance to endocrine therapy have worse prognoses and are independent risk factors for progression after palbociclib therapy. The constructed nomogram could help predict the survival and guide the use of palbociclib.

Study on the modification and anti-tumor activity of silybin derivatives for CDK4/6 targeted / 药学学报

By using computer-aided drug design, the activities group model which CDK4/6 inhibitors on the market were introduced to silybin C-7, and a series of silybin derivatives were designed and synthesized, and the structure was confirmed by MS, 13C NMR and 1H NMR. The in vitro antitumor activity evaluation of the target compound was carried out by MTT method, and the in vitro anti-tumor activity was carried out in human hepatocellular carcinoma cells (HepG-2). Experimental results show that all compounds are higher than the activity of the parent silybin, of which compound I1 has a certain inhibitory effect on human HepG-2 cells, which is worth further study.

Complete response in metastatic breast cancer with visceral crisis using a combination of cyclin-dependent kinase 4/6 inhibitor and aromatase inhibitor: A case report from the eastern region of India

Patients with metastatic breast cancer (MBC) in visceral crisis require systemic chemotherapy. However, a coexisting cardiac failure that contradicts the use of systemic chemotherapy often demands an alternative treatment. Here, we report a case of hormone-receptor-positive MBC with cardiological comorbidities. She was treated with a combination treatment of tablet Ribociclib (600 mg once daily for 21 days followed by 7 days gap) and tablet Letrozole (2.5 mg once daily). The patient had a complete metabolic response in 18-Fluorodeoxyglucose Positron Emission tomography-Computed Tomography (18F-FDG PET/CT), after 6 months of treatment. Combination treatment with Ribociclib and Letrozole is beneficial in postmenopausal females with hormone receptor-positive and human epidermal growth factor receptor 2 neu-negative MBC in visceral crisis who have a contraindication to chemotherapy.

Expert consensus on the management of adverse events of CDK4/6 inhibitors in breast cancer / 中华肿瘤杂志

Cyclin-dependent kinases 4/6 (CDK4/6) inhibitors are anti-tumor agents for the treatment of hormone receptor-positive breast cancer. Palbociclib, abemaciclib and dalpiciclib have been approved for the treatment of breast cancer in China. Common adverse effects of CDK4/6 inhibitors include bone marrow suppression, gastrointestinal toxicities, liver dysfunction, and skin or subcutaneous tissue adverse reactions (AEs). The Breast Cancer Expert Group of Chinese Society of Clinical Oncology (CSCO) summarized the incidence, clinical manifestations, and grading of the AEs. This expert consensus reports measures of AE management on the basis of experience of clinical practice and the latest advances worldwide, aiming to guide clinical practice by the way of managing AE and help to choose the best treatment regimen.

CDK4/6 signaling pathway and its targeted therapeutic agents in cancer therapy: a review / 生物工程学报

The development and progression of most cancers have been well recognized as the result of highly activated cell cycle. Cyclin dependent kinase 4/6 plays important roles not only in mitosis, but also in multiple biological processes that contribute to cancer development, such as aging, apoptosis and histone modification. Three FDA approved CDK4/6 inhibitors, Palbociclib, Ribociclib and Abemaciclib, have been used as targeted cancer therapeutic agents to benefit patients with endocrine therapy-resistant breast cancer and other types of cancer, prolonging their survival. However, the clinical application of these inhibitors also leads to acquired drug resistance and other problems. This paper reviews the regulatory roles of CDK4/6, the application of CDK4/6 inhibitors in cancer and the challenge of drug resistance.

Selective inhibition of CDK4/6: A safe and effective strategy for developing anticancer drugs

The sustained cell proliferation resulting from dysregulation of the cell cycle and activation of cyclin-dependent kinases (CDKs) is a hallmark of cancer. The inhibition of CDKs is a highly promising and attractive strategy for the development of anticancer drugs. In particular, third-generation CDK inhibitors can selectively inhibit CDK4/6 and regulate the cell cycle by suppressing the G1 to S phase transition, exhibiting a perfect balance between anticancer efficacy and general toxicity. To date, three selective CDK4/6 inhibitors have received approval from the U.S. Food and Drug Administration (FDA), and 15 CDK4/6 inhibitors are in clinical trials for the treatment of cancers. In this perspective, we discuss the crucial roles of CDK4/6 in regulating the cell cycle and cancer cells, analyze the rationale for selectively inhibiting CDK4/6 for cancer treatment, review the latest advances in highly selective CDK4/6 inhibitors with different chemical scaffolds, explain the mechanisms associated with CDK4/6 inhibitor resistance and describe solutions to overcome this issue, and briefly introduce proteolysis targeting chimera (PROTAC), a new and revolutionary technique used to degrade CDK4/6.

Tratamiento del Cáncer de Mama Metastásico, Receptor Hormonal Positivo, Her 2 Negativo: Enfoque actual a Dianas Terapéuticas / Treatment of Metastatic Breast Cancer, Hormone Receptor Positive, Her 2 Negative: Current Approach to Therapeutic Targets

En el cáncer de mama luminal, la terapia hormonal está indicada en adyuvancia y neoadyuvancia. El estadio metastásico incluye un grupo heterogéneo de tumores que varían de acuerdo con el sitio de metástasis, tiempo de aparición, condición general de las pacientes, entre otras características intrínsecas del tumor. Esto establece tiempos de sobrevida con rangos variables de meses a muchos años. Los estrógenos actúan en receptores de membrana citoplasmática y nuclear: en las células neoplásicas estimulan la transcripción del ARN, con persistencia de la proliferación. El bloqueo de la acción hormonal en el cáncer avanzado encuentra mecanismos de resistencia con el uso de vías de señalización paralelas, este conocimiento ha permitido el desarrollo de inhibidores de CDK 4/6, mTOR y PIK3-CA, que se recomiendan en enfermedad metastásica, con prolongación significativa de la supervivencia global. En crisis visceral aún se mantiene el uso de quimioterapia sistémica secuencial o combinada

For a patient with estrogen receptor positivebreast cancer, the adjuvant and neoadjuvant endocrine therapy has an absolute benefit. The metastatic stage includes a diverse group of tumors that vary according to the site of metastasis, time of appear, general condition of the patients, and other intrinsic characteristics of the tumor. survival in cancer varies according these features, from a few months to many years. Estrogen hormones stimulate nuclear and cytoplasmic receptors. In neoplastic cells, estrogen regulate RNA transcription, with persistence of proliferation. The blocking of hormonal action in metastatic cancer, has resistance mechanisms with the use of parallel signaling pathways, this knowledge has allowed the development of inhibitors of CDK 4/6, mTOR and PIK3-CA, which are recommended in metastatic disease. with significant prolongation of overall survival. In visceral crisis, the use of sequential or combined systemic chemotherapy is still maintained

Rational drug design, synthesis, and biological evaluation of novel chiral tetrahydronaphthalene-fused spirooxindole as MDM2-CDK4 dual inhibitor against glioblastoma

Simultaneous inhibition of MDM2 and CDK4 may be an effective treatment against glioblastoma. A collection of chiral spirocyclic tetrahydronaphthalene (THN)-oxindole hybrids for this purpose have been developed. Appropriate stereochemistry in THN-fused spirooxindole compounds is key to their inhibitory activity: selectivity differed by over 40-fold between the least and most potent stereoisomers in time-resolved FRET and KINOMEscan® assays. Studies in glioblastoma cell lines showed that the most active compound induced apoptosis and cell cycle arrest by interfering with MDM2 -P53 interaction and CDK4 activation. Cells treated with showed up-regulation of proteins involved in P53 and cell cycle pathways. The compound showed good anti-tumor efficacy against glioblastoma xenografts in mice. These results suggested that rational design, asymmetric synthesis and biological evaluation of novel tetrahydronaphthalene fused spirooxindoles could generate promising MDM2-CDK4 dual inhibitors in glioblastoma therapy.

Anticancer activity of britannin through the downregulation of cyclin D1 and CDK4 in human breast cancer cells

Aim of the Study: Both apoptotic induction and cell cycle blockade in cancer cells are effective strategies to eliminate cancer cells. Many conventional cancer drugs that induce apoptosis and inhibit cell cycle progression have been reported as potential therapeutics for various types of cancer. Britannin is a natural sesquiterpene lactone that its profound anticancer properties were revealed in our previous study. In this study, we evaluated the effects of britannin on the cell cycle distribution and also cell cycle-related proteins. Materials and Methods: Analysis of cell cycle distribution was carried out using flow cytometer. The effects of britannin on cyclin D1 and CDK4 expression were evaluated using the Western blot. Results: The obtained results show that britannin at the low concentrations induces cell growth inhibition mainly through G1-phase arrest while it seems that apoptosis contributes to cell growth inhibitory effect of high doses of britannin. Reduction of cyclin D1 and CDK4 protein levels were also observed after treating cancer cells with britannin. Conclusion: The obtained results reveal that britannin can inhibit MCF-7 and MDA-MB-468 breast cancer cells proliferation through arresting cell cycle progression through cyclin D1/CDK4-mediated pathway

miR-15b-5p Inhibits Choroid Melanoma Cell Proliferation by Targeting CDK4 / 中国医科大学学报

Objective To explore the inhibitory effects of miR-15 b-5 p on choroid melanoma cell line proliferation by targeting CDK4.Methods Dual-luciferase assay was used to verify the direct binding site between miR-15 b-5 p and CDK4 3'-UTR. MUM-2 B cells were cultured in vitro and transfected with negative control RNA, miR-15 b-5 p mimics, inhibitor normal control (nc) RNA, and miR-15 b-5 p inhibitor. qRT-PCR was used to detect miR-15 b-5 p expression, Western blotting was used to measure the expression levels of CDK4 in the cells, CCK-8 assay was used to detect proliferation capacity, and flow cytometry was used to detect cell cycle. Results Dual-luciferase assay verified that miR-15 b-5 p could bind to CDK4 mRNA 3'-UTR successfully. Compared to the negative control group, the mimics group showed significantly increased miR-15 b-5 p expression, decreased CDK4 levels, decreased cell proliferation rate, and increased proportion of G1-phase cells. Compared to the inhibitor nc group, the inhibitor group showed significantly decreased miR-15 b-5 p expression (t = 25.01, P ＜ 0.000 1), increased CDK4 protein level, increased cell proliferation rate, and decreased proportion of G1-phase cells.Conclusion miR-15 b-5 p can target CDK4, induce G1 phase arrest in cells, and thus, reduce the proliferation rate of choroid melanoma cells.

Sargentodoxa cuneata combined with chemotherapy drug 5-fluorouracil inhibits growth of liver cancer cells / 中草药

Objective To investigate the effect of Sargentodoxa cuneata extracts combined with 5-fluorouracil on the growth inhibition of human hepatoma HepG2 cells, and explore its mechanism. Methods HepG2 cells were cultured in vitro and treated with different concentrations of S. cuneata extracts. The effect of S. cuneata extracts on cell growth inhibition was detected by MTT assay, and the subsequent experimental concentration was selected. HepG2 cells were randomly divided into four groups: control group, S. cuneata extracts group (40 mg/L), 5-fluorouracil (10 μmol/L) group, and combination group (S. cuneata extracts 40 mg/L + 5-fluorouracil 10 μmol/L). Cell proliferation inhibition rate was detected by MTT assay and cell cycle was detected by flow cytometry. The expression levels of nuclear antigen PCNA, Cyclin D1, and cell cycle-dependent protein kinase CDK4 were detected by Western blotting. Results The results of MTT assay showed that S. cuneata extracts inhibited the proliferation of HepG2 cells in a concentration-dependent manner (P < 0.05), and S. cuneata extracts with a concentration of 40 mg/L was selected for subsequent experiments. Compared with the control group, the cell proliferation inhibition rate of the S. cuneata extracts group and the 5-fluorouracil group was significantly increased, the proportion of G0/G1 phase cells was significantly increased, and the proportion of cells in the S phase and G2/M phase was significantly decreased (P < 0.05). The protein expression levels of PCNA, Cyclin D1, and CDK4 in the cells were significantly decreased (P < 0.05). Compared with the 5-fluorouracil group, the combination group significantly inhibited the proliferation of HepG2 cells, blocked the cell cycle, and inhibited the protein expression of PCNA, Cyclin D1, and CDK4 in the cells (P < 0.05). Conclusion S. cuneata extracts combined with 5-fluorouracil enhances the growth inhibition of hepatocellular carcinoma HepG2 cells, and its mechanism may be related to the inhibition of the protein expression of PCNA, Cyclin D1, and CDK4 related to the expression levels of PCNA, Cyclin D1, and CDK4 in the inhibited cells.

Molecular mcchanism of deguelin-induced apoptosis and cell cycle arrest in lung cancer cells in vitro / 中国药理学通报

Aim To explore whether deguelin can block cell cycle and cell migration, inhibit the proliferation of non-small cell lung cancer cells.Methods H1299 cells were treated with 1.562 5, 3.125, 6.25, 12.5, 25, 50 μmol·L-1 deguelin for different time(24, 48, 72 h); cell viability was detected by CCK-8 assay, and cell migration ability was tested by scratch assay.H1299 cells were treated with 1.5, 3, 6 μmol·L-1 deguelin for 24 h.Flow cytometry with PI single staining and Annexin V-FITC/PI double staining experiment were used to evaluate cell cycle and apoptosis.qPCR was used to detect the regulatory effects of deguelin and its carbamate derivative on the Cyclin D-CDK4/6 complex at the gene level.Results Deguelin inhibited cell growth and the IC50 value of deguelin was(5.47±0.97),(4.01±0.45),(2.86±0.19)μmol·L-1 when treated with 24, 48, 72 h respectively.Deguelin also inhibited the healing ability of H1299 cells and the migration of H1299 cells significantly(P<0.05).Deguelin could block H1299 cell cycle in G1 phase.Flow cytometry combined with Annexin V-FITC/PI double staining showed that deguelin could induce apoptosis of H1299 cells.qPCR experiments showed that deguelin could down-regulate the expression of CDK4, CDK6 and Cyclin D1 genes significantly(P<0.05).Conclusions Deguelin may regulate cell cycle by down-regulating CDK4, CDK6 and Cyclin D1 genes in the cell cycle regulation system, and reduce the migration ability of tumor cells to induce apoptosis.

Mutations of Pl6INK4a/CDK4/CCND1 genes in 134 Chinese melanoma patients and their clinical significance / 基础医学与临床

Objective To investigate the frequency of P16INK4a, CDK4 and CCND1 gene mutations in Chinese melanoma patients and to find out the potential clinical significance. Methods The samples in this study were collected from 134 melanoma patients(37 acral melanomas, 87 mucosal melanomas, 10 nonacral skin melanomas), hospitalized in Beijing Cancer Hospital from January 2010 to December 2014.The mutation status of P1 6INK4a, CDK4 and CCNDl was detected by PCR amplification and Sanger sequence. Statistical analyses were used to investigate the correlation between gene mutation and prognosis. Results Among 134 samples, the mutation frequency of P16INK4a, CDK4, CCNDl was 8.2％(11/134), 0.75％(1/134), 0％(0/134) respectively.81.8％ (9/11) of the P16INK4a gene mutation may affect protein function.The median survival time of melanoma patients with P16INK4a mutations was significantly shorter than the patients without Pl6INK4a mutations (X2 = 8.872, P＜0.01).P16INK4a gene mutation was an independent prognostic factor for melanoma (P＜0.05). Conclusions P16INK4a may be a breaking point of targeted therapy for melanoma.

The effects of sodium fluoride on histone acetylation of CyclinD1/cyclin-dependent kinases 4 gene in human osteoblasts / 中华地方病学杂志

Objective To establish an model of fluorosis with human primary osteoblasts in vitro and to detect the influences of different doses of sodium fluoride (NaF) on histone acetylation of CyclinD1,cyclindependent kinases 4 (CDK4) gene in human osteoblasts,then to explore the molecular mechanism of skeletal fluorosis from epigenetic perspective of the cell cycle regulation related genes.Methods Human primary osteoblasts from bone tissues of trauma surgery healthy people (car accident) were isolated by enzyme digestion and identified.The osteoblasts were treated with 0,125,250,500 and 1 000 μmol/L NaF for 72 h.The level of histone acetylation (H3K9,H3K14,H4K12,H4K16) in the transcription regulatory region (ChIP1 region) and in the coding region (ChIP2 region) of CyclinD1 and CDK4 genes were detected by quantitative chmmatin immuno-precipitation (Q-ChIP).Results ①After human osteoblasts were treated with 0,125,250,500 and 1 000 μmol/L NaF,respectively,the levels of histone acetylation of H3K9 in ChIP1 transcription regulatory region of CyclinD1 gene were 1.152 ± 0.104,1.174 ± 0.187,1.090 ± 0.176,1.170 ± 0.197 and 1.147 ± 0.097,respectively,the differences were not statistically significant (F =0.524,P ＞ 0.05);the average levels of histone acetylation of H3K14 were 1.495 ± 0.117,1.465 ± 0.069,1.470 ± 0.187,1.760 ± 1.089 and 1.341 ± 0.443,the differences were not statistically significant (F =0.841,P ＞ 0.05);the levels of histone acetylation of H4K12 were 1.239 ± 0.286,0.702 ± 0.063,0.765 ± 0.370,1.011 ± 0.321 and 1.319 ± 0.026,the differences were not statistically significant (F =2.329,P ＞ 0.05);the levels of histone acetylation of H4K16 were 1.452 ± 0.217,1.621 ± 0.165,1.462 ±0.090,1.510 ± 0.146 and 1.564 ± 0.154,the differences were not statistically significant (F =0.123,P ＞ 0.05).②The levels of histone acetylation of H3K9 in ChIP1 transcription regulatory region of CDK4 were 1.472 ± 0.163,1.580 ± 0.161,1.585 ± 0.132,1.451 ± 0.136 and 1.560 ± 0.039,the differences were not statistically significant (F =0.461,P ＞ 0.05);the levels of histone acetylation of H3K14 were 0.919 ± 0.149,0.900 ± 0.059,0.911 ±0.162,0.663 ± 0.049 and 0.841 ± 0.122,the differences were not statistically significant (F =0.974,P ＞ 0.05);the levels of histone acetylation of H4K12 were 0.456 ± 0.142,0.911 ± 0.126,0.969 ± 0.185,1.110 ± 0.146 and 0.931 ± 0.141,the differences were not statistically significant (F=5.459,P ＞ 0.05);the levels of histone acetylation of H4K16 were 1.315 ± 0.083,1.374 ± 0.153,1.423 ± 0.055,1.300 ± 0.132 and 1.385 ± 0.696,the differences were not statistically significant (F =1.663,P ＞ 0.05).③The differences of histone acetylation levels of H3K9,H3K14,H4K12 and H4K16 in ChIP2 coding region of CyclinD1 and CDK4 genes were not statistically significant between NaF treatment groups (F =0.392,0.823,0.999,0.397,0.705,0.049,1.065,0.196,P ＞ 0.05).Conclusion The histone acetylation of CyclinD1 and CDK4 may not be involved in the transcriptional regulation in human primary osteoblasts treated with fluoride.

Effect of high expression of Zwint on the proliferation of hepatoma cells and the prognosis of liver transplantation for hepatocellular carcinoma / 器官移植

Objective To investigate the expression of zeste white 10 interactor (Zwint) in primary hepatocellular carcinoma (HCC) and its effect on the prognosis of liver transplantation for HCC. Methods HCC tissues, paracancerous tissues and clinical data of 50 liver transplant recipients for HCC were collected. The expression levels of Zwint messenger RNA (mRNA) and Zwint protein in 20 pairs of HCC tissues and paracancerous tissues of 20 liver transplant recipients for HCC were compared using real-time fluorescence quantitative polymerase chain reaction (PCR), Western Blot and immunohistochemistry (IHC). Two HCC cell lines HepG-2 which interfered with the expression of Zwint successfully were selected as si-Zwint-1 group and si-Zwint-2 group, and the blank control was taken as si-NC group. The cell proliferation and cell cycle of various groups were compared using cell counting kit (CCK) -8 experiment, flat-cloning assay and cell cycle experiment. The consistency of the expression of Zwint and cyclin D1 in HCC tissues and cells was analyzed using Western Blot and IHC. The enrolled patients were divided into high expression group (22 cases) and low expression group (28 cases) based on the median of Zwint protein expression level, and the relationship of the expression level of Zwint protein and clinical characteristics, overall survival rate and disease free survival rate of liver transplant recipients for HCC was analyzed. Results The results of real-time fluorescence quantitative PCR showed that the expression level of Zwint mRNA in HCC tissues was higher than that of paracancerous tissues (P=0.03). The results of Western Blot and IHC showed that the expression level of Zwint protein in HCC tissues was higher than that of paracancerous tissues(both P<0.05).After the Zwint gene of HCC cell line HepG-2 was interfered,CCK-8 and flat-cloning assay showed that the cell proliferation potential was significantly weakened (all P<0.01), and the cell cycle arrested at stage G1(all P<0.05). The expression level of Zwint protein was closely related to tumor diameter and tumor, node, metastasis (TNM) staging (all P<0.05). The overall survival rate of liver transplant recipients for HCC in the high Zwint expression group was lower than that of the low expression group (P=0.02). Conclusions Zwint is highly expressed in HCC tissues, and it can promote the proliferation of HCC cells through regulating cell cycle. The expression level of Zwint is negatively correlated with the prognosis of liver transplantation for HCC.

Effects of cerebral ischemic postconditioning on expressions of Notch1,Cyclin D1 and CDK4 proteins in hippocampus of rats / 吉林大学学报(医学版)

Objective:To investigate the effects of cerebral ischemic postconditioning (CIP)on the expressions of Cyclin D1 and CDK4 proteins in hippocampal neurons of the rats with global cerebral ischemia and reperfusion (I/R)based on Notch1 signaling pathway,and to explore the mechanisms.Methods:A total of 128 healthy male SD rats were randomly divided into sham operation group,I/R group (modified Pulsinelli four vessel occlusion method), CIP group (repeated 3 times of reperfusion or blocking blood vessel before complete reperfusion)and DAPT group (intraperitoneal injection of 10 mg·kg-1 ·d-1 DAPT 3 h before CIP),and there were 32 rats in each group.HE staining was used to observe the morphology of the neurons at 6, 24, 48 and 72 h after ischemia;immunohistochemical staining was used to observe the expressions of Cyclin D1, CDK4 and Notch1 in the hippocampus of the rats;Western blotting method was used to observe the expression levels of Cyclin D1,CDK4 and Notch1 proteins in the hippocampus of the rats at different time points. Results:The HE staining results showed that compared with sham operation group,the structure of neurons in hippocampus area of the rats in I/R group was damaged and the survival rate of neurons was significantly decreased (P <0.05).Compared with I/R group,the survival rates of neurons in the hippocampus area of the rats in CIP group were significantly increased at the corresponding time (P <0.05).Compared with CIP group,the survival rates of neurons in hippocampus area of the rats in DAPT group at the corresponding time were significantly decreased (P < 0.05 ). The immunohistochemical staining results showed that compared with sham operation group,the number of cells with positive Notch1,Cyclin D1 and CDK4 in I/R group was increased (P < 0.05).Compared with I/R group,the number of Cyclin D1 and CDK4 positive cells in CIP group was decreased (P <0.05),and the number of Notch1 positive cells of was significantly increased (P <0.05).Compared with CIP group,the number of Cyclin D1 and CDK4 positive cells in DAPT group was increased (P < 0.05 ),and the number of Notch1 positive cells was significantly decreased (P < 0.05 ). The Western blotting results showed that compared with sham operation group,the expression levels of Notch1,Cyclin D1 and CDK4 proteins in the hippocampus of the rats in I/R group were increased (P <0.05);compared with I/R group,the expression levels of Cyclin D1 and CDK4 proteins in the hippocampus of the rats in CIP group were significantly decreased (P <0.05),and the expression level of Notch1 protein in the hippocanpus of the rats was significantly increased (P < 0.05 ); compared with CIP group,the expression levels of Cyclin D1 and CDK4 proteins in the hippocampus of the rats in DAPT group were increased (P <0.05),and the expression level of Notch1 protein was significantly decreased (P < 0.05).Conclusion:CIP may play an important role in protecting the neurons by increasing the activity of Notch1 and inhibiting the expressions of Cyclin D1 and CDK4.

Ribociclib: new antitumor drug of cyclindependent kinase 4/6 inhibitor / 药物评价研究

Ribociclib is an oral small molecule cyclindependent kinase 4/6 inhibitor,which inhibits tumor progression by inhibiting the conversion of tumor cells from G1 phase to S phase.The combination ofribociclib and letrozole was approved in the United States on March 13,2017 as a treatment for HR+/HER2-advanced and metastatic breast cancer patients.Clinical results showed that the drug on advanced and metastatic tumors had a significant inhibitory effect and could extend the survival of patients without deterioration compared with using letrozole alone.The incidence of adverse drug reactions is higher,but the tolerance is better.This article focuses on pharmacodynamics,pharmacokinetic,clinical results and adverse effects of this drug.

Aberrant Activation of Cdc2/cyclin B1 Is Involved in Initiation of Cytoskeletal Pathology in Murine Niemann-Pick Disease Type C / 华中科技大学学报（医学）（英德文版）

Niemann-Pick disease type C (NPC) is a fatal,neurovisceral lipid storage disease,neuropathologically characterized by cytoplasmic sequestration of glycolipids in neurons,progressive neuronal loss,neurofibrillary tangles (NFTs) formation,and axonal spheroids (AS).Cytoskeletal pathology including accumulation of hyperphosphorylated cytoskeletal proteins is a neuropathological hallmark of the mouse model of NPC (npc mice).With a goal of elucidating the mechanisms underlying the lesion formation,we investigated the temporal and spatial characteristics of cytoskeletal lesions and the roles of cdc2,cdk4,and cdk5 in lesion formation in young npc mice.Cytoskeletal lesions were detectable in npc mice at three weeks of age.Importantly,concomitant activation of cdc2/cyclin B 1 kinase and accumulation of a subsequently generated cohort of phospho-epitopes were detected.The activation of cdk4/cyclin D1 and cdk5/p25 kinases was observed during the fourth week of life in npc mice,and this activation contributed to the lesion formation.We concluded that the progression of cytoskeletal pathology in npc mice older than four weeks is accelerated by the cumulative effect of cdc2,cdk4,and cdk5 activation.Furthermore,cdc2/cyclin B1 may act as a key initial player one week earlier.Targeting cell cycle activation may be beneficial to slow down the NPC pathogenesis.

Circulating Tumor DNA in a Breast Cancer Patient's Plasma Represents Driver Alterations in the Tumor Tissue

Tumor tissues from biopsies or surgery are major sources for the next generation sequencing (NGS) study, but these procedures are invasive and have limitation to overcome intratumor heterogeneity. Recent studies have shown that driver alterations in tumor tissues can be detected by liquid biopsy which is a less invasive technique capable of both capturing the tumor heterogeneity and overcoming the difficulty in tissue sampling. However, it is still unclear whether the driver alterations in liquid biopsy can be detected by targeted NGS and how those related to the tissue biopsy. In this study, we performed whole-exome sequencing for a breast cancer tissue and identified PTEN p.H259fs*7 frameshift mutation. In the plasma DNA (liquid biopsy) analysis by targeted NGS, the same variant initially identified in the tumor tissue was also detected with low variant allele frequency. This mutation was subsequently validated by digital polymerase chain reaction in liquid biopsy. Our result confirm that driver alterations identified in the tumor tissue were detected in liquid biopsy by targeted NGS as well, and suggest that a higher depth of sequencing coverage is needed for detection of genomic alterations in a liquid biopsy.

Effect of RNAi targetingBMI-1 gene on radiosensitivity of esophageal carcinoma cells / 中国癌症杂志

Background and purpose:B cell-specific MLV integration site 1 (BMI-1) gene plays an important role in DNA damage after exposure to irradiation. The present study aimed to investigate the effect ofBMI-1 on radio-sensitivity of esophageal carcinoma cell after down-regulation of BMI-1 expression by silencing siRNA.Methods:Three pairs of siRNA based on the sequences of the BMI-1 mRNA were synthesized (siRNA1, siRNA2 and siRNA3) by compa-ny, and transfected into cultured TE13 cells as the BMI-1 siRNA groups, and a negative one was synthesized to be used as the negative control (NC) group. The untransfected group was named as the control group. BMI-1 mRNA and protein expression in esophageal cancer TE13 cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot in different groups. This study used flow cytometry assay to analyze cell cycle of transfected cells, and examined cellular growth and radiosensitivityin vitro by MTT and clone formation assay. mRNA and protein expression of p16 and CDK4 in esophageal cancer TE13 cells were detected by RT-PCR and Western blot.Results:The results of RT-PCR and Western blot showed that the expressions of BMI-1 at gene and protein levels were inhibited after silencing the BMI-1 gene. The mRNA and protein expression of BMI-1 in BMI-1 siRNA3 group were both significantly lower than that in BMI-1 siRNA1 and 2 groups. There was no significant difference in the cell proliferation among control, NC and BMI-1 siRNA3 groups. The values ofD0,Dq, and SF2 in BMI-1 siRNA3 group were 1.761, 2.122 and 0.6255, respectively, obvi-ously lower than those in control group (2.514, 2.694 and 0.8268) and those in NC group (2.506, 2.664 and 0.8231), while the value of N in BMI-1 siRNA3 group (3.336) was higher than that in control group (2.92) and that in NC group (2.895), which showed higher radiosensitivity in BMI-1 siRNA3 group. In addition, the cell cycle was arrested at G2/M phase after irradiation in control and NC groups. The percentage of G0/G1 phase in BMI-1 siRNA3 group was higher than that of control group and NC group, while the percentage of G2/M phase was lower than those in the latter. The up-regulation of p16 and down-regulation of CDK4 at gene and protein levels were detected after knockdown of BMI-1 expression by siRNA (P<0.01).Conclusion:siRNA could inhibitBMI-1 gene expression in esophageal cancer TE13 cells and enhance radiosensitivity, followed by eliminating the cell cycle arrest at G2/M stage after irradiationin vitro, which is related to the regulation of the protein expression ofp16 andCDK4.