Objective: PD-1/PD-L1 immune checkpoint treatment is effective for some triple-negative breast cancer populations with PD-L1 expression, but the response rate is still not satisfactory. This study aims to explore the mechanism of drug resistance to breast cancer anti-PD-1 therapies and the strategies for overcoming the resistance to PD-1therapies. Methods: By constructing a human triple-negative breast cancer drug-resistant cell line called BT-549R5 and a mouse breast cancer drug-resistant cell line called 4T1R3, and applying the whole-gene shRNA library screening, candidate drug resistance-associated molecules were obtained and verified by cytological experiments. The expression of Tyro3, Axl and MerTK of the TAM family in the 4T1R3 group was tested using the Western blot method. The down-regulation of CDK9 on the effect of T cells killing the BT-549R5 cells was observed through T cell killing tests, while the down-regulation of Tyro3 and CDK9 on the effect of anti-PD-1 therapies for transplanted breast tumors was observed in mouse tumor formation experiments. Results: The cell lines and animal models of breast cancer resistant to PD-1 treatment were successfully constructed. Tyro3, Axl and MerTK were highly expressed in 4T1R3 cells. Whole genome sequencing showed that Tyro3 and CDK9 were highly expressed in BT-549R5 cells. T cell killing experiment showed that the survival rate of BT-549R5 cells in the CDK9 down-regulated group and the control group decreased gradually with the increase of T cells, but the survival rate of BT-549R5 cells in the CDK9 down-regulated group decreased rapidly. Tumor formation experiment in mice showed that under anti-PD-1 treatment, the transplanted tumor in the 4T1R3 cell group grew rapidly compared with the 4T1 cell group (P<0.05), and the tumor volume of the 4T1R3 group was larger than that of the 4T1 group on Day 20. Nevertheless, the tumor growth rates in the CDK9-knockdown 4T1R3 cell group and the Tyro3-knockdown 4T1R3 cell group were similar to that of the 4T1 cell group, and the tumor volumes at day 20 were signiference lower than that of 4T1R3 cell group(P<0.05). Conclusions: Tyro3 and CDK9 are associated with the drug resistance to anti-PD-1 therapies for breast cancer. Inhibiting the expression of Tyro3 and CDK9 can reverse the drug resistance to breast cancer treatment.
Humans ; Animals ; Mice ; c-Mer Tyrosine Kinase/metabolism* ; Receptor Protein-Tyrosine Kinases/genetics* ; Axl Receptor Tyrosine Kinase ; Proto-Oncogene Proteins/metabolism* ; B7-H1 Antigen/genetics* ; Triple Negative Breast Neoplasms/genetics* ; Drug Resistance, Neoplasm ; Biomarkers ; Cell Line, Tumor ; Cyclin-Dependent Kinase 9

Objective: PD-1/PD-L1 immune checkpoint treatment is effective for some triple-negative breast cancer populations with PD-L1 expression, but the response rate is still not satisfactory. This study aims to explore the mechanism of drug resistance to breast cancer anti-PD-1 therapies and the strategies for overcoming the resistance to PD-1therapies. Methods: By constructing a human triple-negative breast cancer drug-resistant cell line called BT-549R5 and a mouse breast cancer drug-resistant cell line called 4T1R3, and applying the whole-gene shRNA library screening, candidate drug resistance-associated molecules were obtained and verified by cytological experiments. The expression of Tyro3, Axl and MerTK of the TAM family in the 4T1R3 group was tested using the Western blot method. The down-regulation of CDK9 on the effect of T cells killing the BT-549R5 cells was observed through T cell killing tests, while the down-regulation of Tyro3 and CDK9 on the effect of anti-PD-1 therapies for transplanted breast tumors was observed in mouse tumor formation experiments. Results: The cell lines and animal models of breast cancer resistant to PD-1 treatment were successfully constructed. Tyro3, Axl and MerTK were highly expressed in 4T1R3 cells. Whole genome sequencing showed that Tyro3 and CDK9 were highly expressed in BT-549R5 cells. T cell killing experiment showed that the survival rate of BT-549R5 cells in the CDK9 down-regulated group and the control group decreased gradually with the increase of T cells, but the survival rate of BT-549R5 cells in the CDK9 down-regulated group decreased rapidly. Tumor formation experiment in mice showed that under anti-PD-1 treatment, the transplanted tumor in the 4T1R3 cell group grew rapidly compared with the 4T1 cell group (P<0.05), and the tumor volume of the 4T1R3 group was larger than that of the 4T1 group on Day 20. Nevertheless, the tumor growth rates in the CDK9-knockdown 4T1R3 cell group and the Tyro3-knockdown 4T1R3 cell group were similar to that of the 4T1 cell group, and the tumor volumes at day 20 were signiference lower than that of 4T1R3 cell group(P<0.05). Conclusions: Tyro3 and CDK9 are associated with the drug resistance to anti-PD-1 therapies for breast cancer. Inhibiting the expression of Tyro3 and CDK9 can reverse the drug resistance to breast cancer treatment.
Humans ; Animals ; Mice ; c-Mer Tyrosine Kinase/metabolism* ; Receptor Protein-Tyrosine Kinases/genetics* ; Axl Receptor Tyrosine Kinase ; Proto-Oncogene Proteins/metabolism* ; B7-H1 Antigen/genetics* ; Triple Negative Breast Neoplasms/genetics* ; Drug Resistance, Neoplasm ; Biomarkers ; Cell Line, Tumor ; Cyclin-Dependent Kinase 9

OBJECTIVE: To investigate the effect of CDK1 interference regulation of PLK1, Aurora B and TRF1 on the proliferation of leukemia cells. METHODS: The human myelogenous leukemia cell line HL-60 was selected as the research object, and the effect of TRF1 expression and its changes on cell proliferation and cycle was investigated by regulating intracellular CDK1 expression. The objects were divided into 5 groups, including control group, shRNA-NC group, CDK1-shRNA group, pcDNA group and pcDNA-CDK1 group. RT-PCR was used to detect the CDK1 expression of cells in each group; colony formation was used to detect the proliferation of the cells. Western blot was used to detect the expression of CDK1, PLK1, Aurora B, TRF1, and cyclin p53, p27, cyclinA. RESULTS: The phosphorylation level of PLK1, Aurora B and the expression of TRF1 in the CDK1-shRNA group were significantly down-regulated as compared with those in the control group (P<0.05). Compared with the control group, the cells in CDK1-shRNA group showed lower clone formation rate, the increasing of cycle-associated proteins p53 and p27 and the decreasing of cyclinA expression (P<0.05). It was shown that interfered CDK1 expression could inhibit the proliferation of HL-60 cells and prolong the time that they enter mitosis, thereby extending the cell cycle. Compared with the control group, the overexpressed CDK1 in the pcDNA-CDK1 group made the phosphorylation level of PLK1, Aurora B, and TRF1 expression increase significantly (P<0.05), also the colony formation rate (P<0.05). The cycle-related proteins p53 and p27 was down-regulated, while cyclinA expression was up-regulate significantly (P<0.05). The results indicted that overexpressed CDK1 could stimulate adverse reactions, thereby promoting the proliferation of HL-60 cells and shortening the cell cycle. CONCLUSION Knocking out CDK1 can inhibit the phosphorylation of PLK1 and Aurora B and negatively regulate TRF1, thereby inhibiting the proliferation of leukemia cells.
CDC2 Protein Kinase ; Cell Cycle Proteins/genetics* ; Cell Proliferation ; Humans ; Leukemia ; Mitosis ; Phosphorylation ; Proto-Oncogene Proteins/genetics*

OBJECTIVE: To investigate the clinical characteristics, diagnosis and treatment of 1 case EBV negative extranodal NK/T cell lymphoma (ENKTL) patients. METHODS: The clinical manifestations, diagnosis and treatment of one case ENKTL patients with EBV negative were analyzed retrospectively. RESULTS: A 46-year-old woman diagnosed as positive for exosanal NK/T cell lymphoma (EBER CONCLUSION EBV negative ENKTL is rare in clinic and easy to be misdiagnosed, so it should be distinguished from peripheral T cell lymphoma. This case was treated with EBV positive ENKTL regimen, with good short-term efficacy.
CDC2 Protein Kinase ; Cell Proliferation ; Female ; Humans ; Leukemia ; Lymphoma, Extranodal NK-T-Cell ; Middle Aged ; Positron Emission Tomography Computed Tomography ; Retrospective Studies

BACKGROUND: Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. METHODS: To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (Δψm) loss. CONCLUSION: Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.
Animals ; Apoptosis ; Blotting, Western ; Calcium-Transporting ATPases ; Cyclin-Dependent Kinase 5 ; Diabetes Mellitus, Type 2 ; Down-Regulation ; Endoplasmic Reticulum Stress ; Endoplasmic Reticulum ; Gene Expression ; Genes, Homeobox ; Glucose ; Hyperglycemia ; Insulin-Secreting Cells ; Membrane Potential, Mitochondrial ; Polymerase Chain Reaction ; Rats ; Reactive Oxygen Species ; Reticulum ; Reverse Transcription ; Up-Regulation

OBJECTIVE: Synaptic vesicle mobilization and neurite outgrowth regulation molecules were examined in modulation of effects of methylphenidate (MPH) in Spontaneous Hypertensive Rats (SHRs), a model for attention-deficit hyperactivity disorder (ADHD). METHODS: We compared the changes in the protein expression level of Cyclin dependent kinase 5 (Cdk5) and molecular substrates of Cdk5; tropomyosin receptor kinase B (TrkB), syntaxin 1A (STX1A) and synaptosomal-associated protein 25 (SNAP25). Comparisons were made in prefrontal cortex of vehicle (distilled water i.p. for 7 days)-treated SHRs, vehicle-treated Wistar Kyoto Rats (WKYs) and MPH (2 mg/kg i.p. for 7 days) treated SHRs. RESULTS: The Cdk5 level of vehicle-treated SHRs was significantly decreased compared to the Cdk5 level of vehicle-treated WKY rats, but was restored to the expression level of vehicle-treated WKYs in MPH-treated SHR. The ratio of p25/p35 was significantly decreased in MPH-treated SHR compared to vehicle-treated SHR. Moreover, TrkB, STX1A and SNAP25 of vehicle-treated SHRs were significantly decreased compared to vehicle-treated WKY rats, but were restored to the expression level of vehicle-treated WKYs in MPH-treated SHR. CONCLUSION: The results show that Cdk5, TrkB, STX1A, and SNAP25 were involved in the modulation of MPH effects in prefrontal cortex of SHRs and play important role in treatment of ADHD.
Animals ; Cyclin-Dependent Kinase 5 ; Methylphenidate ; Neurites ; Phosphotransferases ; Prefrontal Cortex ; Rats ; Rats, Inbred WKY ; Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins ; Synaptic Vesicles ; Synaptosomal-Associated Protein 25 ; Syntaxin 1 ; Tropomyosin ; Water

Mitochondria continuously fuse and divide to maintain homeostasis. An impairment in the balance between the fusion and fission processes can trigger mitochondrial dysfunction. Accumulating evidence suggests that mitochondrial dysfunction is related to neurodegenerative diseases such as Parkinson's disease (PD), with excessive mitochondrial fission in dopaminergic neurons being one of the pathological mechanisms of PD. Here, we investigated the balance between mitochondrial fusion and fission in the substantia nigra of a non-human primate model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD. We found that MPTP induced shorter and abnormally distributed mitochondria. This phenomenon was accompanied by the activation of dynamin-related protein 1 (Drp1), a mitochondrial fission protein, through increased phosphorylation at S616. Thereafter, we assessed for activation of the components of the cyclin-dependent kinase 5 (CDK5) and extracellular signal-regulated kinase (ERK) signaling cascades, which are known regulators of Drp1(S616) phosphorylation. MPTP induced an increase in p25 and p35, which are required for CDK5 activation. Together, these findings suggest that the phosphorylation of Drp1(S616) by CDK5 is involved in mitochondrial fission in the substantia nigra of a non-human primate model of MPTP-induced PD.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine ; Cyclin-Dependent Kinase 5 ; Cyclin-Dependent Kinases ; Dopaminergic Neurons ; Homeostasis ; Mitochondria ; Mitochondrial Dynamics ; Neurodegenerative Diseases ; Parkinson Disease ; Phosphorylation ; Phosphotransferases ; Primates ; Substantia Nigra

PURPOSE: Several studies have shown that the oral cavity is a secondary location for Helicobacter pylori colonization and that H. pylori is associated with the severity of periodontitis. This study investigated whether H. pylori had an effect on the periodontium. We established an invasion model of a standard strain of H. pylori in human periodontal ligament fibroblasts (hPDLFs), and evaluated the effects of H. pylori on cell proliferation and cell cycle progression. METHODS: Different concentrations of H. pylori were used to infect hPDLFs, with 6 hours of co-culture. The multiplicity of infection in the low- and high-concentration groups was 10:1 and 100:1, respectively. The Cell Counting Kit-8 method and Ki-67 immunofluorescence were used to detect cell proliferation. Flow cytometry, quantitative real-time polymerase chain reaction, and western blots were used to detect cell cycle progression. In the high-concentration group, the invasion of H. pylori was observed by transmission electron microscopy. RESULTS: It was found that H. pylori invaded the fibroblasts, with cytoplasmic localization. Analyses of cell proliferation and flow cytometry showed that H. pylori inhibited the proliferation of periodontal fibroblasts by causing G2 phase arrest. The inhibition of proliferation and G2 phase arrest were more obvious in the high-concentration group. In the low-concentration group, the G2 phase regulatory factors cyclin dependent kinase 1 (CDK1) and cell division cycle 25C (Cdc25C) were upregulated, while cyclin B1 was inhibited. However, in the high-concentration group, cyclin B1 was upregulated and CDK1 was inhibited. Furthermore, the deactivated states of tyrosine phosphorylation of CDK1 (CDK1-Y15) and serine phosphorylation of Cdc25C (Cdc25C-S216) were upregulated after H. pylori infection. CONCLUSIONS: In our model, H. pylori inhibited the proliferation of hPDLFs and exerted an invasive effect, causing G2 phase arrest via the Cdc25C/CDK1/cyclin B1 signaling cascade. Its inhibitory effect on proliferation was stronger in the high-concentration group.
Blotting, Western ; CDC2 Protein Kinase ; Cell Count ; Cell Cycle ; Cell Proliferation ; Coculture Techniques ; Colon ; Cyclin B1 ; Cytoplasm ; Fibroblasts ; Flow Cytometry ; Fluorescent Antibody Technique ; G2 Phase ; Helicobacter pylori ; Helicobacter ; Humans ; Methods ; Microscopy, Electron, Transmission ; Mouth ; Periodontal Ligament ; Periodontitis ; Periodontium ; Phosphorylation ; Real-Time Polymerase Chain Reaction ; Serine ; Tyrosine

PURPOSE: The cyclin-dependent kinase 1 (Cdk1) and cyclin B complex performs important roles in the transition from the G2 to M phase in the cell cycle through removal of inhibitory phosphates on Cdk1, and Cdc25B, which is a dual-specific phosphatase, mediates these dephosphorylation events. However, measuring Cdc25B activity by existing methods is hampered by inadequate nonspecific substrates and the need to use a radiolabeled isotope. The present study aimed to develop an improved method with which to properly measure Cdc25B activity using a novel nonradioisotopic assay and Cdc25B overexpression cell lines. MATERIALS AND METHODS: A nonradioisotopic Cdk1 kinase assay, based on Western blotting for retinoblastoma protein and histone H1, was used to analyze Cdc25B activity. Also, stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines were constructed using the tetracycline-regulated expression system and were applied as a tool for screening for inhibitors of Cdc25B. RESULTS: The present study developed and optimized a nonradioisotopic assay method to properly measure Cdc25B activity. Furthermore, we constructed stable Cdc25B2 and Cdc25B3 overexpression HeLa cell lines for the establishment of a strong assay system with which to evaluate the specificity of Cdc25B inhibitors under conditions similar to the intracellular environment. These methods were confirmed as useful tools for measuring Cdc25B activity. CONCLUSION: The nonradioisotopic Cdk1 kinase assay and Cdc25B overexpression cell lines developed in this study can be conveniently used as tools for screening inhibitors of Cdc25B phosphatase as anticancer drugs.
Blotting, Western ; CDC2 Protein Kinase ; cdc25 Phosphatases ; Cell Cycle ; Cell Division ; Cell Line* ; Cyclin B ; HeLa Cells ; Histones ; Humans ; Mass Screening* ; Methods ; Phosphates ; Retinoblastoma Protein ; Sensitivity and Specificity

OBJECTIVESTo explore the protective effects of Tongmai Yizhi Decoction (, TYD), a Chinese herb complex prescription against the impairment of cognitive functions and memory loss in amyloid beta 1-40 (Aβ) peptide and ibotenic (IBO)-induced Alzheimer's disease (AD) model rats.

METHODSThe in vivo model was established by injecting Aβand IBO into left hippocampal CA1 area of Sprague-Dawley (SD) rat to mimic AD. Totally 32 SD rats were divided into 4 groups, including sham operation group, AD model group, TYD group [AD rats treated with TYD at the dosage of 19.44 g/(kg•d) for 4 weeks] and huperzine A group [AD rats treated with huperzine A at the dosage of 40.5 μg/(kg•d) for 4 weeks]. Spatial learning and memory level was detected by Morris Water Maze test. Histological morphology in the hippocampus was tested by hematoxylin-eosin (HE) staining. Cyclin-dependent kinase-5 (Cdk5) protein and gene expression level were investigated by Western blot analysis and real-time quantitative polymerase chain reaction (RT-qPCR), respectively.

RESULTSAβ1-40 and IBO treatment induced longer escape latency of rats, compared with sham operation group from day 25 (P<0.01). However, TYD and huperzine A obviously shortened the escape latency from day 26 (P<0.01). Moreover, the effect of TYD was similar to huperzine A (P>0.05). Furthermore, HE staining also showed that TYD and huperzine A reversed the neuropathological changes in the hippocampus triggered by Aβ1-40 and IBO. TYD and huperzine A effectively reduced the expression levels of Cdk5 protein and gene located in rat hippocampus, compared with the AD model group (P<0.01).

CONCLUSIONTYD could be a promising neuroprotective agent for protecting neuron from AD injury through inhibiting Cdk5 expression.

Alzheimer Disease ; drug therapy ; pathology ; Animals ; Cognition ; drug effects ; Cyclin-Dependent Kinase 5 ; metabolism ; Disease Models, Animal ; Down-Regulation ; drug effects ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Hippocampus ; drug effects ; Male ; Maze Learning ; drug effects ; Memory ; drug effects ; Neuroprotective Agents ; therapeutic use ; Rats ; Rats, Sprague-Dawley