Modification of P13K- and MAPK-dependent chemotaxis in aortic vascular smooth muscle cells by protein kinase CBII

Hyperglycemia increases expression of platelet-derived growth factor (PDGF)-beta receptor and potentiates chemotaxis to PDGF-BB in human aortic vascular smooth muscle cells (VSMCs) via PI3K and ERK/MAPK signaling pathways. The purpose of this study was to determine whether increased activation of protein kinase C (PKC) isoforms had a modulatory effect on the PI3K and ERK/MAPK pathways, control of cell adhesiveness, and movement. All known PKC isoforms were assessed but only PKC alpha and PKC beta II levels were increased in 25 mmol/L glucose. However, only PKC beta II inhibition affected (decreased) PI3K pathway and MAPK pathway activities and inhibited PDGF-beta receptor upregulation in raised glucose, and specific MAPK inhibition was required to completely block the effect of glucose. In raised glucose conditions, activity of the ERK/MAPK pathway, PI3K pathway, and PKC beta II were all sensitive to aldose reductase inhibition. Chemotaxis to PDGF-BB (360 pmol/L), absent in 5 mmol/L glucose, was present in raised glucose and could be blocked by PKC beta II inhibition. Formation of lamellipodia was dependent on PI3K activation and filopodia on MAPK activation; both lamellipodia and filopodia were eliminated when PKC beta II was inhibited. FAK phosphorylation and cell adhesion were reduced by PI3K inhibition, and although MAPK inhibition prevented chemotaxis, it did not affect FAK phosphorylation or cell adhesiveness. In conclusion, chemotaxis to PDGF-BB in 25 mmol/L glucose is PKC beta II-dependent and requires activation of both the PI3K and MAPK pathways. Changes in cell adhesion and migration speed are mediated mainly through the PI3K pathway.

Phase II study of ISIS 3521, an antisense oligodeoxynucleotide to protein kinase C alpha, in patients with previously treated low-grade non-Hodgkin's lymphoma

Background: The purpose of this study was to assess the efficacy and safety of ISIS 3521, an antisense phosphorothioate oligonucleotide to protein kinase C in patients with relapsed low-grade non-Hodgkin's lymphoma (NHL). Patients and methods: Twenty-six patients received ISIS 3521 (2 mg/kg/day) as a continuous infusion over 21 days of each 28-day cycle. Results: The median age of the patients was 53 years (range 37–77). Histological subtypes were low-grade follicular lymphoma (n=22) and B-cell small lymphocytic lymphoma (n=4). Twenty-one (81%) had stage III/IV disease. The median number of previous lines of chemotherapy was two (range one to six). A total of 87 cycles of ISIS 3521 were administered. Twenty-three patients were assessable for response. Three patients achieved a partial response. No complete responses were observed. Ten patients had stable disease. Grade 3–4 toxicity was as follows: neutropenia (3.8%) and thrombocytopenia (26.9%). Conclusions: ISIS 3521 has demonstrated anti-tumour activity in patients with relapsed low-grade NHL. There may be a potential role for this agent in combination with conventional chemotherapy for advanced low-grade lymphoma, and further trials are warranted.

Cyclin G associated kinase interacts with interleukin 12 receptor beta2 and suppresses interleukin 12 induced IFN-gamma production.

BACKGROUND: Although severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation (NPPV), increasing clinical reports showed it was effective in patients with impaired consciousness and even coma secondary to acute respiratory failure, especially hypercapnic acute respiratory failure (HARF). To further evaluate the effectiveness and safety of NPPV for severe hypercapnic encephalopathy, a prospective case-control study was conducted at a university respiratory intensive care unit (RICU) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) during the past 3 years. METHODS: Forty-three of 68 consecutive AECOPD patients requiring ventilatory support for HARF were divided into 2 groups, which were carefully matched for age, sex, COPD course, tobacco use and previous hospitalization history, according to the severity of encephalopathy, 22 patients with Glasgow coma scale (GCS) <10 served as group A and 21 with GCS = 10 as group B. RESULTS: Compared with group B, group A had a higher level of baseline arterial partial CO2 pressure ((102 +/- 27) mmHg vs (74 +/- 17) mmHg, P <0.01), lower levels of GCS (7.5 +/- 1.9 vs 12.2 +/- 1.8, P <0.01), arterial pH value (7.18 +/- 0.06 vs 7.28 +/- 0.07, P <0.01) and partial O(2) pressure/fraction of inspired O(2) ratio (168 +/- 39 vs 189 +/- 33, P <0.05). The NPPV success rate and hospital mortality were 73% (16/22) and 14% (3/22) respectively in group A, which were comparable to those in group B (68% (15/21) and 14% (3/21) respectively, all P > 0.05), but group A needed an average of 7 cm H2O higher of maximal pressure support during NPPV, and 4, 4 and 7 days longer of NPPV time, RICU stay and hospital stay respectively than group B (P <0.05 or P <0.01). NPPV therapy failed in 12 patients (6 in each group) because of excessive airway secretions (7 patients), hemodynamic instability (2), worsening of dyspnea and deterioration of gas exchange (2), and gastric content aspiration (1). CONCLUSIONS: Selected patients with severe hypercapnic encephalopathy secondary to HARF can be treated as effectively and safely with NPPV as awake patients with HARF due to AECOPD; a trial of NPPV should be instituted to reduce the need of endotracheal intubation in patients with severe hypercapnic encephalopathy who are otherwise good candidates for NPPV due to AECOPD.

CDK11(p58) protein kinase activity is associated with Bcl-2 down-regulation in pro-apoptosis pathway.

CDK11(p58), a G2/M-specific protein kinase, has been shown to be associated with apoptosis in many cell lines, with largely unknown mechanisms. Our previous study proved that CDK11(p58)-enhanced cycloheximide (CHX)-induced apoptosis in SMMC-7721 hepatocarcinoma cells. Here we report for the first time that ectopic expression of CDK11(p58) down-regulates Bcl-2 expression and its Ser70, Ser87 phosphorylation in CHX-induced apoptosis in SMMC-7721 cells. Overexpression of Bcl-2 counteracts the pro-apoptotic activity of CDK11(p58). Furthermore, we confirm that the kinase activity of CDK11(p58) is essential to the down-regulation of Bcl-2 as well as apoptosis. Taken together, these results demonstrate that CDK11(p58) down-regulates Bcl-2 in pro-apoptosis pathway depending on its kinase activity, which elicits survival signal in hepatocarcinoma cells.

Cyclin-dependent kinase 11(p58) interacts with HBO1 and enhances its histone acetyltransferase activity.

CDK11(p58), a 58kDa protein of the PITSLRE kinase family, plays an important role in cell cycle progression, and is closely related to cell apoptosis. To gain further insight into the function of CDK11(p58), we screened a human fetal liver cDNA library for its interacting proteins using the yeast two-hybrid system. Here we report that histone acetyltransferase (HAT) HBO1, a MYST family protein, interacts with CDK11(p58) in vitro and in vivo. CDK11(p58) and HBO1 colocalize in the cell nucleus. Recombinant CDK11(p58) enhances the HAT activity of HBO1 significantly in vitro. Meanwhile, overexpression of CDK11(p58) in mammalian cells leads to the enhanced HAT activity of HBO1 towards free histones. Thus, we conclude that CDK11(p58) is a new interacting protein and a novel regulator of HBO1. Both of the proteins may be involved in the regulation of eukaryotic transcription.

The C-terminal kinase domain of the p34cdc2-related PITSLRE protein kinase (p110C) associates with p21-activated kinase 1 and inhibits its activity during anoikis.

The PITSLRE protein kinases are parts of the large family of p34cdc2-related kinases. During apoptosis induced by some stimuli, specific PITSLRE isoforms are cleaved by caspase to produce a protein that contains the C-terminal kinase domain of the PITSLRE proteins (p110C). The p110C induces apoptosis when it is ectopically expressed in Chinese hamster ovary cells. In our study, similar induction of this p110C was observed during anoikis in NIH3T3 cells. To investigate the molecular mechanism of apoptosis mediated by p110C, we used the yeast two-hybrid system to screen a human fetal liver cDNA library and identified p21-activated kinase 1 (PAK1) as an interacting partner of p110C. The association of p110C with PAK1 was further confirmed by in vitro binding assay, in vivo coimmunoprecipitation, and confocal microscope analysis. The interaction of p110C with PAK1 occurred within the residues 210-332 of PAK1. Neither association between p58PITSLRE or p110PITSLRE and PAK1 nor association between p110C and PAK2 or PAK3 was observed. Anoikis was increased and PAK1 activity was inhibited when NIH3T3 cells were transfected with p110C. Furthermore, the binding of p110C with PAK1 and inhibition of PAK1 activity were also observed during anoikis. Taken together, these data suggested that PAK1 might participate in the apoptotic pathway mediated by p110C.