Transcription factor Sp1 is upregulated by PKCι to drive the expression of YAP1 during pancreatic carcinogenesis.

Recently, we identified that the atypical protein kinase C isoform ι (PKCι) enhances the expression of Yes-associated protein 1 (YAP1) to promote the tumorigenesis of pancreatic adenocarcinoma harboring mutant KRAS (mu-KRAS). To advance our understanding about underlying mechanisms, we analyze the transcription of YAP1 in pancreatic cancer cells and reveal that transcription factor specificity protein 1 (Sp1) is upregulated by PKCι and subsequently binds to multiple sites in YAP1 promoter to drive the transactivation of YAP1 in pancreatic cancer cells carrying mu-KRAS. The bioinformatics analysis further substantiates that the expression of PKCι, Sp1 and YAP1 is correlated and associated with the stages and prognosis of pancreatic tumors. Moreover, our apoptotic detection data demonstrate that combination of PKCι and Sp1 inhibitors at subtoxic doses displays synergistic effects on inducing apoptosis and reversing the immunosuppression of pancreatic cancer cells, establishing the combination of PKCι and Sp1 inhibitors as a promising novel therapeutic approach, or an adjuvant strategy to potentiate the antitumor effects of other immunotherapeutic agents in pancreatic cancer treatment.

Mu-KRAS attenuates Hippo signaling pathway through PKCι to sustain the growth of pancreatic cancer.

The atypical protein kinase C isoform ι (PKCι) is upregulated, which cooperates with mutated KRAS (mu-KRAS) to promote the development of pancreatic cancers. However, the exact role of PKCι in KRAS-mediated pancreatic tumorigenesis is not fully defined. In the present study, we demonstrate that mu-KRAS upregulates and activates PKCι, accompanied by dephosphorylation of large tumor suppressor (LATS), a key member of the growth-inhibiting Hippo signaling pathway. As a result, Yes-associated protein 1 (YAP1; a transcriptional coactivator) is dephosphorylated and translocates to the nucleus, which promotes transcription of downstream target genes to sustain the transformed growth of pancreatic cancer cells. In contrast, when PKCι is suppressed by the chemical inhibitor or small-hairpin RNA, the levels of phosphorylated LATS and YAP1 are elevated and YAP1 is excluded from the nucleus, which enhances the susceptibility of pancreatic cancer cells harboring mu-KRAS to apoptosis. These findings shed new light on the mechanisms underlying the pancreatic tumorigenesis initiated by mu-KRAS, and suggest that the PKCι-YAP1 signaling may potentially be therapeutically targeted for restricting the growth and inducing apoptosis in pancreatic tumors expressing mu-KRAS.

[The Effects of PKCι on Anti-tumor Activity of Cytokine-induced Killer Cells Against Pancreatic Cancer Cells and the Possible Underlying Mechanisms].

OBJECTIVE: To study the impact of atypical protein kinase Cι (PKCι) isoform PKC on the pancreatic cancer cells towards the tumoricidal effect of cytokine-induced killer (CIK) cells and explore its mechanisms. METHODS: CIK cells were prepared by inducing mononuclear cells isolated from the peripheral blood of healthy people with interleukin-2 (IL-2), interferon (IFN) and CD3 mAb and subsequently co-cultured with pancreatic epithelial cell HPDE6-C7, pancreatic cancer cells MiaPaCa and PANC-1 with or without PKC inhibitor named sodium thiomalate (ATM). All cells were divided into control group, ATM group, co-culture group with CIK and co-culture group with CIK+ATM. Cell count was used to detect the growth of each group from 1 to 8 d. Flow cytometry was used to detect the death rate of the cell lines after 48 h cell culture in each group. The small hairpin RNA (shRNA) was used for PKCι knockdown and the recombinant plasmid transfection was for PKCι overexpression in pancreatic cancer cells. Western blot and real-time fluorescent quantitative PCR (qRT-PCR) were utilized to determine the expression of PKCι protein and the impact on gene expression of transforming growth factor-ß (TGF-ß), a downstream effector modulated by PKC. Different mass concentrations of TGF-ß (1, 10, 20 ng/mL) were added into the co-culture of MiaPaCa and PANC-1 with CIK. The cell death rate was detected by flow cytometry 48 h later, so as to explore the possible mechanisms of the impact of PKCι on the tumoricidal effects of CIK cells. RESULTS: ATM and CIK were shown to suppress the growth and induce apoptosis or death of pancreatic cancer cells, meanwhile, ATM can enhance the tumoricidal effect of CIK on pancreatic cancer cells. Moreover, we found that PKCι knockdown in pancreatic cancer cells can down-regulate the gene expression of TGF-ß. In return, PKCι overexpression in pancreatic cancer cells can increase the gene expression of TGF-ß. The death rate of cancer cells with 10, 20 ng/mL TGF-ß was lower compared with the control group (P < 0.05). CONCLUSIONS: PKCι knockdown in pancreatic cancer cells can not only inhibit the growth of pancreatic cancer cells, but also enhance the tumoricidal effects of CIK on cancer cells. The possible mechanism of PKCι is to affect the immune escape of tumor cells by regulating the expression of TGF-ß.

Preparation and Performance Evolution of Plasma Sprayed Abradable CuAl/PHB-NiAl Layered Seal Coatings.

In this study, a double-layered CuAl/PHB-NiAl seal coating was prepared on a GH4169 substrate by atmospheric plasma spraying. The evolution of the microstructure and mechanical properties of the coating under simulated working conditions was studied. The surface hardness of as-sprayed coating decreased with an increase in the temperature from 25 to 700 °C, decreasing from 90.42 HR15Y to 66.83 HR15Y. A CuO phase was formed in the coating and the oxidation weight gain rate increased with an increase in the temperature when the coating was constantly oxidized at 500~700 °C for 100 h. The hardness of metal matrix in the coating increased with the extension in the oxidation time at 600 °C, increasing from 120.8 HV0.1 to 143.02 HV0.1. The residual stress of the as-sprayed porous CuAl top-coating was less than that of the top-coating/bond-coating interface, and it is further relieved by about 15~20 MPa after heat treatment. The coating porosity first increased and then decreased when the oxidation time was 1000 h. The further ablation of PHB and the formation of oxide were concluded to be the main reasons for the evolution of porosity.

An improved beam splitting method for intensity modulated proton therapy.

The pencil beam algorithm (PBA) has become the predominant dose calculation method in proton therapy, due to its high level of efficiency. However, density heterogeneity decreases the accuracy of PBA. To improve PBA's accuracy, a beam splitting method is used to divide the original scanning beam into multiple thinner beamlets. Beam splitting should ensure that the beamlets' summed fluence is as close to the original beam fluence as possible, while keeping the spatial variance of beamlets small, and minimizing the number of beamlets. In this work, the generalized differential evolution (GDE) algorithm is utilized for the optimal scheme. Under reasonable constraints for the radius and weight of beamlets, several schemes are optimized via the GDE algorithm. In order to achieve a trade-off between accuracy and calculation speed, three hexagon-based schemes, which split the original beam into 7, 13, and 19 beamlets, respectively, are proposed and compared with the scheme of Raystation 4.5. The fluence distribution calculated by the schemes with 13 beamlets and 19 beamlets are demonstrated to be more accurate than the Raystation scheme, which has 19 beamlets, with a maximum absolute difference between the summed beamlets fluence and the original beam fluence of 2.12%, and 0.93%, respectively. Furthermore, beam splitting schemes are implemented into a proton dose calculation algorithm based on the KylinRay-IMPT TPS. These schemes, based on the dose algorithm, are compared with the Monte Carlo program TOPAS 3.2 in slab geometry with lateral heterogeneity. The dose, calculated by the dose algorithm using a scheme of 13 beamlets, shows a good agreement with the dose from TOPAS. In addition, an abdominal geometry is used for further verification. Gamma analysis passing rates greater than 99.7% are observed, with a 2%/2 mm criterion. Thus, the accuracy and effectiveness of the improved beam splitting method are preliminarily verified.

Study on the interaction between silver nanoparticles and nucleic acids in the presence of cetyltrimethylammonium bromide and its analytical application.

A novel method is proposed in this paper, that is the silver nanoparticle (nanoAg)-cetyltrimethylammonium bromide (CTMAB) is used as the probe of resonance light scattering (RLS) for the determination of nucleic acids. Under optimum conditions, there are linear relationships between the quenching extent of RLS and the concentration of nucleic acids in the range of 4.0x10(-9)-2.0x10(-6)gmL(-1) for fish sperm DNA (fsDNA), 7.0x10(-9)-1.8x10(-6)gmL(-1) for calf thymus DNA (ctDNA) and 6.0x10(-9)-1.0x10(-6)gmL(-1) for yeast RNA (yRNA). The detection limits (S/N=3) of fsDNA, ctDNA and yRNA are 2.7x10(-10)gmL(-1), 4.8x10(-10)gmL(-1) and 7.2x10(-10)gmL(-1), respectively. The studies indicate that there are interactions among nanoAg, CTMAB and fsDNA through electrostatic and chemical affinity, and the nanoAg-CTMAB complex can induce the structural change of base stacking and helicity of fsDNA.