Sorafenib plus intensive chemotherapy improves survival in patients with newly diagnosed, FLT3-internal tandem duplication mutation-positive acute myeloid leukemia.

BACKGROUND: The addition of midostaurin to induction chemotherapy improves survival in younger patients with newly diagnosed, FLT3-mutated acute myeloid leukemia (AML). Sorafenib is a potent multikinase inhibitor with efficacy when given as monotherapy. The authors investigated whether the addition of sorafenib to intensive induction chemotherapy improves outcomes in patients with FLT3-internal tandem duplication (ITD)-mutated AML. METHODS: In total, 183 patients who were newly diagnosed with FLT3-ITD-mutated AML between February 2001 and December 2017 were identified. Of these, 79 patients (43%) underwent intensive chemotherapy with the addition of sorafenib, and 104 (57%) received intensive chemotherapy alone. Propensity score matching identified 42 patients in each cohort. RESULTS: The overall response rate was 98% in the sorafenib cohort and 83% in the intensive chemotherapy cohort (P = .057). The median follow-up was 54 months. The median event-free survival was 35 months in the sorafenib cohort and 8 months in the intensive chemotherapy cohort (P = .019), and the median overall survival was 42 and 13 months, respectively (P = .026). With censoring at the time of allogeneic stem cell transplantation, the median event-free survival was 31 and 8 months in the sorafenib and intensive therapy cohorts, respectively (P = .031), and the median overall survival was not reached and 10 months, respectively (P = .001). Multivariate Cox proportional hazards models confirmed that treatment with sorafenib was a favorable prognostic factor (P = .009; hazard ratio, 0.558; 95% CI, 0.360-0.865). CONCLUSIONS: The addition of sorafenib improves survival in patients with FLT3-ITD-mutated AML regardless of whether they undergo allogeneic stem cell transplantation.

An Involvement of PI3-K/Akt Activation and Inhibition of AIF Translocation in Neuroprotective Effects of Undecylenic Acid (UDA) Against Pro-Apoptotic Factors-Induced Cell Death in Human Neuroblastoma SH-SY5Y Cells.

Undecylenic acid (UDA), a naturally occurring 11-carbon unsaturated fatty acid, has been used for several years as an economical antifungal agent and a nutritional supplement. Recently, the potential usefulness of UDA as a neuroprotective drug has been suggested based on the ability of this agent to inhibit µ-calpain activity. In order to verify neuroprotective potential of UDA, we tested protective efficacy of this compound against cell damage evoked by pro-apoptotic factors (staurosporine and doxorubicin) and oxidative stress (hydrogen peroxide) in human neuroblastoma SH-SY5Y cells. We showed that UDA partially protected SH-SY5Y cells against the staurosporine- and doxorubicin-evoked cell death; however, this effect was not connected with its influence on caspase-3 activity. UDA decreased the St-induced changes in mitochondrial and cytosolic AIF level, whereas in Dox-model it affected only the cytosolic AIF content. Moreover, UDA (1-40 µM) decreased the hydrogen peroxide-induced cell damage which was connected with attenuation of hydrogen peroxide-mediated necrotic (PI staining, ADP/ATP ratio) and apoptotic (mitochondrial membrane potential, caspase-3 activation, AIF translocation) changes. Finally, we demonstrated that an inhibitor of PI3-K/Akt (LY294002) but not MAPK/ERK1/2 (U0126) pathway blocked the protection mediated by UDA in all tested models of SH-SY5Y cell injury. These in vitro data point to UDA as potentially effective neuroprotectant the utility of which should be further validated in animal studies.

In vitro toxicity in long-term cell culture of MR contrast agents targeted to cartilage evaluation.

OBJECTIVE: Contrast-enhanced magnetic resonance (MR) imaging methods have been proposed for non-invasive evaluation of osteoarthritis (OA). We measured cell toxicities of cartilage-targeted low-generation dendrimer-linked nitroxide MR contrast agents and gadopentetate dimeglumine (Gd-DTPA) on cultured chondrocytes. DESIGN: A long-term Swarm rat chondrosarcoma chondrocyte-like cell line was exposed for 48-h to different salts (citrate, maleate, tartrate) and concentrations of generation one or two diaminobutyl-linked nitroxides (DAB4-DLN or DAB8-DLN), Gd-DTPA, or staurosporine (positive control). Impact on microscopic cell appearance, MTT spectrophotometric assays of metabolic activity, and quantitative PicoGreen assays of DNA content (cell proliferation) were measured and compared to untreated cultures. RESULTS: Chondrocyte cultures treated with up to 7.5 mM Gd-DTPA for 48-h had no statistical differences in DNA content or MTT reaction compared to untreated cultures. At all doses, DAB4-DLN citrate treated cultures had results similar to untreated and Gd-DTPA-treated cultures. At doses >1 mM, DAB4-DLN citrate treated cultures showed statistically greater DNA and MTT reaction than maleate and tartrate DAB4-DLN salts. Cultures exposed to 5 mM or 7.5 mM DAB8-DLN citrate exhibited rounded cells, poor cell proliferation, and barely detectable MTT reaction. Treatment with 0.1 µM staurosporine caused chondrocyte death. CONCLUSION: Long-term exposure, greater than clinically expected, to either DAB4-DLN citrate or Gd-DTPA had no detectable toxicity with results equivalent to untreated cultures. DAB4-DLN citrate was more biocompatible than either the maleate or tartrate salts. Cells exposed for 48-h to 5 mM or 7.5 mM DAB8-DLN salts demonstrated significant cell toxicity. Further evaluation of DAB8-DLN with clinically appropriate exposure times is required to determine the maximum useful concentration.

Effect of the protein kinase C inhibitor, staurosporine, on the high dose of methamphetamine-induced behavioral sensitization to dizocilpine (MK-801).

RATIONALE: In our preliminary study, methamphetamine (METH) at 2.5 mg/kg, but not at 1.0 mg/kg, induced a delayed increase in glutamate levels in the nucleus accumbens (NAc). We hypothesize that repeated increases in glutamate levels produces behavioral sensitization to a selective uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, dizocilpine (MK-801), and that an activation of protein kinase C (PKC) plays an important role for this sensitization. OBJECTIVES: This study was conducted to confirm delayed increases in glutamate levels induced by a higher dose of METH (2.5 mg/kg), and to examine the effect of straurosporine, a PKC inhibitor, on the higher dose of METH-induced sensitization to dizocilpine. METHODS: The effects of METH on extracellular glutamate levels in the NAc were studied using in vivo microdialysis. Locomotor activity was measured by using an infrared sensor. RESULTS: METH at 2.5 mg/kg, but not at 1.0 mg/kg, induced delayed increases in glutamate levels. The acute administration of staurosporine did not affect the locomotor activity by a single injection of METH (2.5 mg/kg). Repeated METH administrations (2.5 mg/kg, once in every other day, for five times) developed behavioral sensitization to the locomotion-inducing effect of dizocilpine (0.2 mg/kg), a selective uncompetitive NMDA receptor antagonist. Staurosporine (0.1 mg/kg), given 120 min later for every METH treatment, inhibited the development of behavioral sensitization to dizocilpine. CONCLUSIONS: These results suggest the involvement of increased glutamate levels and an activation of PKC in delayed-induced synaptic and cellular plasticity underlying the higher dose of METH-induced behavioral sensitization to dizocilpine.

Reduction of diabetic macular edema by oral administration of the kinase inhibitor PKC412.

PURPOSE: To evaluate the efficacy and safety of PKC412, an orally administered kinase inhibitor, in subjects with diabetic macular edema. METHODS: This was a randomized (1:1:1:1), multicenter, double-masked, parallel-group study in which subjects (n = 141) received placebo or PKC412 (50, 100, or 150 mg/d) for up to 3 months. Subjects were 18 to 85 years of age and had retinal thickening that met predefined criteria and best corrected visual acuity of 55 letters or more. Efficacy was based on changes in retinal thickening measured by grading of fundus photographs and optical coherence tomography (OCT) and changes in visual acuity. RESULTS: Grading of fundus photographs showed a statistically significant decrease in the area of greatest retinal thickening in patients receiving 150 mg/d of PKC412 (P = 0.032). OCT demonstrated that the two higher doses of PKC412 caused a significant decrease in thickening in the region of greatest thickening and in the fovea (P < or = 039), with response in the high-dose group significantly different from that in the placebo group (difference = -66.69 micro m [95.2% CI: -128.57 to -4.81]; P = 0.030). Retinal volume for all locations also showed a significant decrease from baseline in the 100- and 150-mg/d PKC412 groups (P < or = 004), and the 150-mg/kg group showed significantly less retinal volume than the placebo group at 3 months (difference = -0.46 mm(3) [95.2% CI: -0.86-0.06]; P = 0.019). There was a small (4.36 letters), but significant (P = 0.007), improvement in visual acuity at 3 months compared with baseline in the 100-mg/d PKC412 group. Gastrointestinal side effects (diarrhea, nausea, and vomiting) were the most common adverse events attributed to the drug. Dose-related effects were observed for tolerability, glycemic control, and liver toxicity. CONCLUSIONS: Orally administered PKC412 at doses of 100 mg/d or higher may significantly reduce macular edema and improve visual acuity in diabetic subjects. However, concern regarding liver toxicity with systemic therapy makes local delivery an appealing approach.

Combination therapy with irinotecan and protein kinase C inhibitors in malignant glioma.

The topoisomerase-I inhibitor irinotecan (CPT-11) is currently used in Phase I/II trials for the treatment of patients with recurrent malignant gliomas. Protein kinase C (PKC) inhibitors such as high-dose tamoxifen and hypericin also have been used in the treatment of malignant gliomas. The current study examined the role of PKC inhibitors as chemosensitizers for CPT-11 and their proposed mechanism of action. Two glioma cell lines (A-172 and U-87) and one primary glioma cell culture (LA-567) were used. Proliferation ((3)H-thymidine) and cytotoxicity (methylthiotetrazole) studies were performed using CPT-11 (0-100 microM) alone, 7-ethyl-10-hydroxy camptothecin (SN-38) (0-1000 nM) alone or in the presence of a PKC inhibitor, tamoxifen (10 microM), hypericin (10 microM), calphositin C (400 nM), or staurosporine (10 nM). The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL) assay was used to determine apoptosis as the mechanism of cytotoxicity; alterations in bcl-2 and bax expression were determined using Western blot analysis. Conversion of CPT-11 to SN-38 by glioma cells was determined using high-performance liquid chromatography (HPLC) analysis. Increasing CPT-11 and SN-38 concentrations induced cytotoxic morphologic changes, decreased proliferation, and increased cytotoxicity on all glioma cell lines tested. These changes were increased in the presence of a PKC inhibitor. The mechanism of the cytotoxicity was determined to be apoptosis by the TUNEL assay. The combination of a PKC inhibitor with CPT-11 or SN-38 led to decreased expression of the antiapoptotic protein bcl-2, and increased expression of the proapoptotic protein bax. HPLC analysis demonstrated conversion of CPT-11 to SN-38 by glioma cells. A combination of CPT-11 or SN-38 with a PKC inhibitor was found to lead to a decrease in proliferation and an increase in apoptosis in malignant glioma cells. The induction of apoptosis was secondary to a decrease in bcl-2 and an increase in bax expression. Glioma cells are capable of converting CPT-11 to SN-38 by intrinsic tumor carboxylesterases.