Pyruvate dehydrogenase kinase 1 and carbonic anhydrase IX targeting in hypoxic tumors.

Pyruvate dehydrogenase kinase 1 (PDHK1) and carbonic anhydrase IX (CAIX) are some of the most hypoxia-inducible proteins associated with tumors, implicated in glucose metabolism and pH regulation, respectively. They both appear to be necessary for model tumor growth, and their high level of expression in human tumors predicts poor patient outcome. Another thing they have in common is that hypoxia not only induces their expression but also their enzymatic activity. This work therefore simultaneously targets these two hypoxia-inducible proteins either pharmacologically or genetically in vitro and in vivo, leading to decreased cancer cell survival and significantly slower model tumor growth. It also suggests that CAIX and PDHK1 are important for cells originating from a colorectal primary tumor, as well as from its metastasis. Moreover, our analysis reveals a unique relationship between these two HIF-1 target genes. In conclusion, the attributes of PDHK1 and CAIX predict them to be promising targets for the design of new, specific inhibitors that could negatively influence tumor cell proliferation and survival, or increase efficacy of standard treatment regimens, and at the same time avoid normal tissue toxicity.

Local control of glomus tumors of the head & neck by radiation therapy and surgery.

PURPOSE: Glomus tumors are rare tumors, highly vascular and typically radiosensitive. Therapeutic options include surgery, radiation therapy (RT), embolisation or any combination of them, but the appropriate treatment still remains a challenge. The purpose of this study was to report the results of local control of 7 patients with glomus tumors treated with surgery and external beam RT (EBRT). METHODS: All of the patients underwent primary surgery and then postoperative EBRT. Follow-up was calculated from the date of initiation of EBRT and ranged from 3 to 15 years (mean 7.14, median 6.2). The likelihood of local control was analysed using the Kaplan-Meier product limit method. We also analysed the average duration of response between two groups of patients with different doses of EBRT as well as the presence of acute and late EBRT complications. RESULTS: Local control was obtained in 6/7 (85.7%) patients. Moreover, local control was achieved in 3/4 (75%) patients with recurrent glomus tumors, while in patients with postoperative residual disease local control was obtained in 3/3 (100%) of them. Patients who received <50 Gy (n=2) had shorter average duration of response compared to patients who received >50 Gy (n=5; p=0.248). There were no severe treatment complications. CONCLUSION: Surgery and RT represent an appropriate treatment approach for advanced glomus tumors with acceptable complications.

Association of decreased NK cell activity and IFNγ expression with pSTAT dysregulation in breast cancer patients.

PURPOSE: Impaired IFNγ production in peripheral blood lymphocytes (PBL) and their subsets reflects immunosuppression and inadequate antitumor immune response in cancer patients. Decreased function of natural killer (NK) cells has not been investigated in breast cancer with respect to altered pSTAT signaling pathways. METHODS: PBL of breast cancer patients and healthy controls were analyzed for IFNγ and pSTAT1 expression and NK cell activity using flow cytometry and (51)Cr-release assay, respectively. The level of pSTAT1, 3 and 5 was investigated by Western blotting. RESULTS: Our results indicated that PBL and CD3(-) CD16(+) NK cells of patients had significantly lower level of IFNγ. The patients had a significantly decreased NK cell cytotoxicity compared to controls, with the decrease being dependent on the stage of disease. Positive correlation between IFNγ level in PBL and NK cytotoxicity in controls and patients was also shown. The PBL of patients, compared to controls, expressed lower level of pSTAT1, 3 and 5. The patients' T and NK cell subsets had lower pSTAT1 level. CONCLUSION: This study indicates that pSTAT1 in PBL of breast cancer patients could be a biomarker of decreased NK cell cytotoxicity and IFNγlevel that are associated with progression of this disease.

Novel aspects of in vitro IL-2 or IFN-α enhanced NK cytotoxicity of healthy individuals based on NKG2D and CD161 NK cell receptor induction.

As IL-2 and IFN-α modulate NK cell activity it was of interest to investigate the expression of newly defined NK cell receptors and augmented NK cell activity in healthy individuals after cytokine in vitro treatment. Peripheral blood lymphocytes (PBL) obtained from 31 healthy volunteers treated for 18 h with 200 IU/ml IL-2 and 250 IU/ml IFN-α were evaluated for NK cell cytotoxicity. Expression of NKG2D, CD161, CD158a, CD158b receptors was analyzed on CD3⁻CD16+ NK cells, cytotoxic CD16(bright) and regulatory CD16(dim) subsets by FACS flow. The found induced significant in vitro enhancement of NK cell activity by both cytokines is supported by specific cytokine induction in PBL of pSTAT1 and pSTAT5, determined by Western blotting, as well as induction of IRF-1 transcription. Both cytokines induce significant up-regulation of NKG2D expression while only IFN-α induced significant up-regulation of CD161, with no alteration in KIR expression by either cytokine on CD3⁻CD16+ NK cells. Investigated cytokines did not induce change in NK cell bright and dim subset distribution. Moreover, we find that, not only cytokine receptor induction on the CD3⁻CD16+ NK cells, but also simultaneous increase in their percentage and/or density on CD16(bright) and CD16(dim) subsets, represent good indicators of receptor cytokine-susceptibility. As the role of NK cells has been shown in the loss of tolerance, infection and cancer, the data obtained in this study may be of help in NK cell profiling, by giving referent values of cytokine-induced novel NK cell receptor expression either in evaluation of these diseases or in immunomonitoring during cytokine immunotherapy.

Effect of four-week metformin treatment on plasma and erythrocyte antioxidative defense enzymes in newly diagnosed obese patients with type 2 diabetes.

The principal metabolic effect of metformin-an oral antihyperglycaemic agent-is the improvement in the sensitivity of peripheral tissues and liver to insulin. This study examined the effect of metformin monotherapy on antioxidative defence system activity in erythrocytes and plasma in diabetic patients. We studied the effect of metformin treatment on the activities of Cu, Zn-superoxide dismutase (EC 1. 15. 1. 1.), catalase (EC 1. 11. 1. 6.) and glutathione peroxidase (EC 1. 11. 1. 9.) in relation to lipid peroxidation products and reduced glutathione level in plasma and erythrocytes. In this study we also examined erythrocytes' susceptibility to H2O2-induced oxidative stress during metformin therapy. Although metformin monotherapy ameliorated the imbalance between free radical-induced increase in lipid peroxidation (by reducing the MDA level in both erythrocytes and plasma) and decreased plasma and cellular antioxidant defences (by increasing the erythrocyte activities of Cu, Zn, SOD, catalase and GSH level) and decreased erythrocyte susceptibility to oxidative stress, it had negligible effect to scavenge Fe ion-induced free radical generation in a phospholipid-liposome system.