Phase II study of dichloroacetate, an inhibitor of pyruvate dehydrogenase, in combination with chemoradiotherapy for unresected, locally advanced head and neck squamous cell carcinoma.

Chemoradiotherapy (CRT) for locally-advanced head and neck squamous cell carcinoma (LA-HSNCC) yields 5-year survival rates near 50% despite causing significant toxicity. Dichloroacetate (DCA), a pyruvate dehydrogenase kinase metabolic inhibitor, reduces tumor lactate production and has been used in cancer therapy previously. The safety of adding this agent to CRT is unknown. Our randomized, placebo-controlled, double-blind phase II study added DCA to cisplatin-based CRT in patients with LA-HNSCC. The primary endpoint was safety by adverse events (AEs). Secondary endpoints compared efficacy via 3-month end-of-treatment response, 5-year progression-free and overall survival. Translational research evaluated pharmacodynamics of serum metabolite response. 45 participants (21 DCA, 24 Placebo) were enrolled from May 2011-April 2014. Higher rates of all-grade drug related fevers (43% vs 8%, p = 0.01) and decreased platelet count (67% vs 33%, p = 0.02) were seen in DCA versus placebo. However, there were no significant differences in grade 3/4 AE rates. Treatment compliance to DCA/placebo, radiation therapy, and cisplatin showed no significant difference between groups. While end-of-treatment complete response rates were significantly higher in the DCA group compared to placebo (71.4% vs 37.5%, p = 0.0362), survival outcomes were not significantly different between groups. Treatment to baseline metabolites demonstrated a significant drop in pyruvate (0.47, p < 0.005) and lactate (0.61, p < 0.005) in the DCA group. Adding DCA to cisplatin-based CRT appears safe with no detrimental effect on survival and expected metabolite changes compared to placebo. This supports further investigation into combining metabolic agents to CRT. Trial registration number: NCT01386632, Date of Registration: July 1, 2011.

Metformin and sodium dichloroacetate effects on proliferation, apoptosis, and metabolic activity tested alone and in combination in a canine prostate and a bladder cancer cell line.

An important approach in tumor therapy is combining substances with different action mechanisms aiming to enhance the antineoplastic effect, decrease the therapeutic dosage, and avoid resistance mechanisms. Moreover, evaluating compounds already approved for the treatment of non-neoplastic diseases is promising for new antineoplastic therapies. Sodium dichloroacetate (DCA) reactivates oxidative phosphorylation in the cancer cell mitochondria, reducing apoptosis resistance in cancer cells. Furthermore, metformin inhibits the proliferation of tumor cells and CD133+ cancer -stem-like cells. In the present study, we evaluated the independent and synergistic effect of metformin and DCA on the metabolic activity, cell proliferation, and apoptosis of a canine prostate adenocarcinoma (Adcarc1258) and a transitional cell carcinoma cell line (TCC1506) in comparison to a primary canine fibroblast culture. Determining metformin uptake in tumor cells was performed by quantitative HPLC. Depending on the dosage, metformin as a single agent inhibited the metabolic activity and cell proliferation of the tumor cells, showing only minor effects on the fibroblasts. Furthermore, 1 mM metformin increased apoptosis over 96 h in the tumor cell lines but not in fibroblasts. Additionally, metformin uptake into the tumor cells in vitro was measurable by quantitative HPLC. Synergistic effects for the combination therapy were observed in both neoplastic cell lines as well as in the fibroblasts. Based on these results, metformin might be a promising therapeutic agent for canine urogenital tumors. Further studies on kinetics, toxicology, bioavailability, and application of metformin in dogs are necessary.

Sodium dichloroacetate attenuates the growth of B16-F10 melanoma in vitro and in vivo: an opportunity for drug repurposing.

Sodium dichloroacetate (DCA) is a metabolic regulator used to treat diabetes. Since DCA inhibits pyruvate dehydrogenase kinase, decreasing lactic acid formation, it can reverse the Warburg effect in cancer cells, promoting apoptosis. Therefore, this study aimed to investigate the potential of DCA as a drug repurposing candidate for the treatment of melanoma. For the in-vitro assay, murine B16-F10 melanoma cells were treated with 0.5, 1, 5, 10, 20 or 50 mM DCA for 3 days, analyzed with the crystal violet method. The in-vivo effect of DCA was evaluated in B16-F10 tumor-bearing C57BL/6 mice treated with different doses of DCA (0, 25, 75 or 150 mg/kg) by gavage for 10 days, followed by measurement of tumor volume. Upon necropsy, representative slices of lung, liver, kidney, spleen and intestine were collected, processed and submitted for histopathological examination. The DCA concentrations of 10, 20 and 50 mM reduced B16-F10 cell viability after 48 and 72 h of treatment, whereas 20 and 50 mM were effective after 24 h of treatment. A significant reduction in tumor growth was observed in B16-F10 melanoma bearing mice at all doses, with no change in body weight or histology. DCA attenuates the growth of B16-F10 melanoma in vitro and in vivo, without systemic toxic effects. Therefore, DCA is a candidate for drug repurposing against melanomas.

Exposure of Rats to Multiple Oral Doses of Dichloroacetate Results in Upregulation of Hepatic Glutathione Transferases and NAD(P)H Dehydrogenase [Quinone] 1.

Dichloroacetate (DCA) is an investigational drug that is used in the treatment of various congenital and acquired disorders of energy metabolism. Although DCA is generally well tolerated, some patients experience peripheral neuropathy, a side effect more common in adults than children. Repetitive DCA dosing causes downregulation of its metabolizing enzyme, glutathione transferase zeta 1 (GSTZ1), which is also critical in the detoxification of maleylacetoacetate and maleylacetone. GSTZ1 (-/-) knockout mice show upregulation of glutathione transferases (GSTs) and antioxidant enzymes as well as an increase in the ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH), suggesting GSTZ1 deficiency causes oxidative stress. We hypothesized that DCA-mediated depletion of GSTZ1 causes oxidative stress and used the rat to examine induction of GSTs and antioxidant enzymes after repeated DCA exposure. We determined the expression of alpha, mu, pi, and omega class GSTs, NAD(P)H dehydrogenase [quinone] 1 (NQO1), gamma-glutamylcysteine ligase complex (GCLC), and glutathione synthetase (GSS). GSH and GSSG levels were measured by liquid chromatography-tandem mass spectrometry. Enzyme activity was measured in hepatic cytosol using 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nitrobenzene, and 2,6-dichloroindophenol as substrates. In comparison with acetate-treated controls, DCA dosing increased the relative expression of GSTA1/A2 irrespective of rodent age, whereas only adults displayed higher levels of GSTM1 and GSTO1. NQO1 expression and activity were higher in juveniles after DCA dosing. GSH concentrations were increased by DCA in adults, but the GSH:GSSG ratio was not changed. Levels of GCLC and GSS were higher and lower, respectively, in adults treated with DCA. We conclude that DCA-mediated depletion of GSTZ1 causes oxidative stress and promotes the induction of antioxidant enzymes that may vary between age groups. SIGNIFICANCE STATEMENT: Treatment with the investigational drug, dichloroacetate (DCA), results in loss of glutathione transferase zeta 1 (GSTZ1) and subsequent increases in body burden of the electrophilic tyrosine metabolites, maleylacetoacetate and maleylacetone. Loss of GSTZ1 in genetically modified mice is associated with induction of glutathione transferases and alteration of the ratio of oxidized to reduced glutathione. Therefore, we determined whether pharmacological depletion of GSTZ1 through repeat administration of DCA produced similar changes in the liver, which could affect responses to other drugs and toxicants.

Effects of Multiple Doses of Dichloroacetate on GSTZ1 Expression and Activity in Liver and Extrahepatic Tissues of Young and Adult Rats.

Glutathione transferase zeta 1 (GSTZ1), expressed in liver and several extrahepatic tissues, catalyzes dechlorination of dichloroacetate (DCA) to glyoxylate. DCA inactivates GSTZ1, leading to autoinhibition of its metabolism. DCA is an investigational drug for treating several congenital and acquired disorders of mitochondrial energy metabolism, including cancer. The main adverse effect of DCA, reversible peripheral neuropathy, is more common in adults treated long-term than in children, who metabolize DCA more quickly after multiple doses. One dose of DCA to Sprague Dawley rats reduced GSTZ1 expression and activity more in liver than in extrahepatic tissues; however, the effects of multiple doses of DCA that mimic its therapeutic use have not been studied. Here, we examined the expression and activity of GSTZ1 in cytosol and mitochondria of liver, kidney, heart, and brain 24 hours after completion of 8-day oral dosing of 100 mg/kg per day sodium DCA to juvenile and adult Sprague Dawley rats. Activity was measured with DCA and with 1,2-epoxy-3-(4-nitrophenoxy)propane (EPNPP), reported to be a GSTZ1-selective substrate. In DCA-treated rats, liver retained higher expression and activity of GSTZ1 with DCA than other tissues, irrespective of rodent age. DCA-treated juvenile rats retained more GSTZ1 activity with DCA than adults. Consistent with this finding, there was less measurable DCA in tissues of juvenile than adult rats. DCA-treated rats retained activity with EPNPP, despite losing over 98% of GSTZ1 protein. These data provide insight into the differences between children and adults in DCA elimination under a therapeutic regimen and confirm that the liver contributes more to DCA metabolism than other tissues. SIGNIFICANCE STATEMENT: Dichloroacetate (DCA) is one of few drugs exhibiting higher clearance from children than adults, after repeated doses, for reasons that are unclear. We hypothesized that juveniles retain more glutathione transferase zeta 1 (GSTZ1) than adults in tissues after multiple DCA doses and found this was the case for liver and kidney, with rat as a model to assess GSTZ1 protein expression and activity with DCA. Although 1,2-epoxy-3-(4-nitrophenoxy)propane was reported to be a selective GSTZ1 substrate, its activity was not reduced in concert with GSTZ1 protein.

Metformin enhances cytotoxic action of dichloroacetate against Lewis lung carcinoma cells in vitro.

Tumor cell metabolism is considered one of the hallmarks of cancer. This concept is exploited in the development of new ways of anticancer therapy based on the use of substances capable of changing drastically bioenergetic metabolism of tumor cells. Among them, sodium dichloroace-tate (DCA), an inhibitor of pyruvate dehydrogenase kinase, and metformin (MTF), an antidiabetic hypoglycemic drug, an inhibitor of the mitochondrial respiratory chain (complex I), both have been long used in clinical non-oncological practice, and presently are considered promising candidates in oncology. AIM: To study the capability of MTF to enhance the antitumor action of DCA against Lewis lung carcinoma cells in vitro. MATERIALS AND METHODS: LLC/R9, a low metastatic variant of Lewis lung carcinoma cells, was used. Effects of 30 mM DCA in combination with 2 mM MTF on cell survival, cell cycle distribution, apoptosis, mitochondrial potential, intracellular ATP level, glucose consumption, and lactate production rates were determined in vitro. RESULTS: MTF was shown to enhance the cytotoxic/cytostatic action of DCA against LLC/R9 cells in vitro. Treatment of LLC/R9 cells with 30 mM DCA in combination with 2 mM MTF resulted in a 39% decrease in the number of viable cells (p < 0.05), a 2.8-fold increase of the number of dead cells (p < 0.05), a near 2-fold decrease in the proportion of cells at the S-phase (p < 0.05), a 4-fold increase in the apoptosis (p < 0.05) and significant reduction (p < 0.05) of the mitochondrial membrane potential of tumor cells as compared to corresponding values in control. DCA alone reduced glucose consumption and lactate production rates by more than 26% (p < 0.05) and 34% (p < 0.05), respectively, whereas MTF counteracted these effects. Nevertheless, in the cells treated with both DCA and DCA in combination with MTF, the intracellular adenosine triphosphate increased by 33-35% compared with that in the control (p < 0.05). CONCLUSION: MTF enhanced the cytotoxic/cytostatic action of DCA against LLC/R9 cells in vitro, which points on their possible synergistic antitumor action in vivo.

GPR30-Expressing Gastric Chief Cells Do Not Dedifferentiate But Are Eliminated via PDK-Dependent Cell Competition During Development of Metaplasia.

BACKGROUND & AIMS: Gastric chief cells, a mature cell type that secretes digestive enzymes, have been proposed to be the origin of metaplasia and cancer through dedifferentiation or transdifferentiation. However, studies supporting this claim have had technical limitations, including issues with the specificity of chief cell markers and the toxicity of drugs used. We therefore sought to identify genes expressed specifically in chief cells and establish a model to trace these cells. METHODS: We performed transcriptome analysis of Mist1-CreERT-traced cells, with or without chief cell depletion. Gpr30-rtTA mice were generated and crossed to TetO-Cre mice, and lineage tracing was performed after crosses to R26-TdTomato mice. Additional lineage tracing experiments were performed using Mist1-CreERT, Kitl-CreERT, Tff1-Cre, and Tff2-Cre mice crossed to reporter mice. Mice were given high-dose tamoxifen or DMP-777 or were infected with Helicobacter pylori to induce gastric metaplasia. We studied mice that expressed mutant forms of Ras in gastric cells, using TetO-KrasG12D, LSL-KrasG12D, and LSL-HrasG12V mice. We analyzed stomach tissues from GPR30-knockout mice. Mice were given dichloroacetate to inhibit pyruvate dehydrogenase kinase (PDK)-dependent cell competition. RESULTS: We identified GPR30, the G-protein-coupled form of the estrogen receptor, as a cell-specific marker of chief cells in gastric epithelium of mice. Gpr30-rtTA mice crossed to TetO-Cre;R26-TdTomato mice had specific expression of GPR30 in chief cells, with no expression noted in isthmus stem cells or lineage tracing of glands. Expression of mutant Kras in GPR30+ chief cells did not lead to the development of metaplasia or dysplasia but, instead, led to a reduction in labeled numbers of chief cells and a compensatory expansion of neck lineage, which was derived from upper Kitl+ clones. Administration of high-dose tamoxifen, DMP-777, or H pylori decreased the number of labeled chief cells. Chief cells were eliminated from epithelia via GPR30- and PDK-dependent cell competition after metaplastic stimuli, whereas loss of GRP30 or inhibition of PDK activity preserved chief cell numbers and attenuated neck lineage cell expansion. CONCLUSIONS: In tracing studies of mice, we found that most chief cells are lost during metaplasia and therefore are unlikely to contribute to gastric carcinogenesis. Expansion of cells that coexpress neck and chief lineage markers, known as spasmolytic polypeptide-expressing metaplasia, does not occur via dedifferentiation from chief cells but, rather, through a compensatory response from neck progenitors to replace the eliminated chief cells.

MiR-107 confers chemoresistance to colorectal cancer by targeting calcium-binding protein 39.

BACKGROUND: Chemoresistance remains a critical event that accounts for colorectal cancer (CRC) lethality. The aim of this study is to explore the ability of dichloroacetate (DCA) to increase chemosensitivity in CRC and the molecular mechanisms involved. METHODS: The effects of combination treatment of DCA and oxaliplatin (L-OHP) were analysed both in vitro and in vivo. The DCA-responsive proteins in AMPK pathway were enriched using proteomic profiling technology. The effect of DCA on CAB39-AMPK signal pathway was analysed. In addition, miRNA expression profiles after DCA treatment were determined. The DCA-responsive miRNAs that target CAB39 were assayed. Alterations of CAB39 and miR-107 expression were performed both in vitro and on xenograft models to identify miR-107 that targets CAB39-AMPK-mTOR signalling pathway. RESULTS: DCA increased L-OHP chemosensitivity both in vivo and in vitro. DCA could upregulate CAB39 expression, which activates the AMPK/mTOR signalling pathway. CAB39 was confirmed to be a direct target of miR-107 regulated by DCA. Alterations of miR-107 expression were correlated with chemoresistance development in CRC both in vitro and in vivo. CONCLUSION: These findings suggest that the miR-107 induces chemoresistance through CAB39-AMPK-mTOR pathway in CRC cells, thus providing a promising target for overcoming chemoresistance in CRC.

GSTZ1 genotypes correlate with dichloroacetate pharmacokinetics and chronic side effects in multiple myeloma patients in a pilot phase 2 clinical trial.

Dichloroacetate (DCA) is an investigational drug targeting the glycolytic hallmark of cancer by inhibiting pyruvate dehydrogenase kinases (PDK). It is metabolized by GSTZ1, which has common polymorphisms altering enzyme or promoter activity. GSTZ1 is also irreversibly inactivated by DCA. In the first clinical trial of DCA in a hematological malignancy, DiCAM (DiChloroAcetate in Myeloma), we have examined the relationship between DCA concentrations, GSTZ1 genotype, side effects, and patient response. DiCAM recruited seven myeloma patients in partial remission. DCA was administered orally for 3 months with a loading dose. Pharmacokinetics were performed on day 1 and 8. Trough and peak concentrations of DCA were measured monthly. GSTZ1 genotypes were correlated with drug concentrations, tolerability, and disease outcomes. One patient responded and two patients showed a partial response after one month of DCA treatment, which included the loading dose. The initial half-life of DCA was shorter in two patients, correlating with heterozygosity for GSTZ1*A genotype, a high enzyme activity variant. Over 3 months, one patient maintained DCA trough concentrations approximately threefold higher than other patients, which correlated with a low activity promoter genotype (-1002A, rs7160195) for GSTZ1. This patient displayed the strongest response, but also the strongest neuropathy. Overall, serum concentrations of DCA were sufficient to inhibit the constitutive target PDK2, but unlikely to inhibit targets induced in cancer. Promoter GSTZ1 polymorphisms may be important determinants of DCA concentrations and neuropathy during chronic treatment. Novel dosing regimens may be necessary to achieve effective DCA concentrations in most cancer patients while avoiding neuropathy.

Mitochondrial Glutathione Transferase Zeta 1 Is Inactivated More Rapidly by Dichloroacetate than the Cytosolic Enzyme in Adult and Juvenile Rat Liver.

Dichloroacetate (DCA) has potential for treating mitochondrial disorders and cancer by activating the mitochondrial pyruvate dehydrogenase complex. Repeated dosing of DCA results in reduced drug clearance due to inactivation of glutathione transferase ζ1 (GSTZ1), its metabolizing enzyme. We investigated the time-course of inactivation of GSTZ1 in hepatic cytosol and mitochondria after one oral dose of 100 mg/kg DCA to female Sprague-Dawley rats aged 4 weeks (young) and 52 weeks (adult) as models for children and adults, respectively. GSTZ1 activity with both DCA and an endogenous substrate, maleylacetone (MA), as well as GSTZ1 protein expression were rapidly reduced in cytosol from both ages following DCA treatment. In mitochondria, loss of GSTZ1 protein and activity with DCA were even more rapid. The cytosolic in vivo half-lives of the loss of GSTZ1 activity with DCA were 1.05 ± 0.03 and 0.82 ± 0.02 h (mean ± S.D., n = 6) for young and adult rats, respectively, with inactivation significantly more rapid in adult rats, p < 0.001. The mitochondrial inactivation half-lives were similar in young (0.57 ± 0.02 h) and adult rats (0.54 ± 0.02 h) and were significantly (p < 0.0001) shorter than cytosolic inactivation half-lives. By 24 h after DCA administration, activity and expression remained at 10% or less than control values. The in vitro GSTZ1 inactivation half-lives following incubation with 2 mM DCA in the presence of physiological chloride (Cl-) concentrations (cytosol = 44 mM, mitochondria = 1-2 mM) exhibited marked differences between subcellular fractions, being 3 times longer in the cytosol than in the mitochondria, regardless of age, suggesting that the lower Cl- concentration in mitochondria explained the faster degradation of GSTZ1. These results demonstrate for the first time that rat mitochondrial GSTZ1 is more readily inactivated by DCA than cytosolic GSTZ1, and cytosolic GSTZ1 is inactivated more rapidly in adult than young rats.

Synergistic Amplification of Oxidative Stress-Mediated Antitumor Activity via Liposomal Dichloroacetic Acid and MOF-Fe2.

Cancer cells are susceptible to oxidative stress; therefore, selective elevation of intracellular reactive oxygen species (ROS) is considered as an effective antitumor treatment. Here, a liposomal formulation of dichloroacetic acid (DCA) and metal-organic framework (MOF)-Fe2+ (MD@Lip) has been developed, which can efficiently stimulate ROS-mediated cancer cell apoptosis in vitro and in vivo. MD@Lip can not only improve aqueous solubility of octahedral MOF-Fe2+ , but also generate an acidic microenvironment to activate a MOF-Fe2+ -based Fenton reaction. Importantly, MD@Lip promotes DCA-mediated mitochondrial aerobic oxidation to increase intracellular hydrogen peroxide (H2 O2 ), which can be consequently converted to highly cytotoxic hydroxyl radicals (•OH) via MOF-Fe2+ , leading to amplification of cancer cell apoptosis. Particularly, MD@Lip can selectively accumulate in tumors, and efficiently inhibit tumor growth with minimal systemic adverse effects. Therefore, liposome-based combination therapy of DCA and MOF-Fe2+ provides a promising oxidative stress-associated antitumor strategy for the management of malignant tumors.

Effect of sodium dichloroacetate on apoptotic gene expression in human leukemia cell lines.

BACKGROUND: Sodium dichloroacetate (DCA) is an agent with anticancer properties against solid tumors. DCA also seems to have antileukemic activity. In order to affirm it we investigate the effect of DCA on cell viability and apoptotic gene expression profiles in leukemia cell lines: CEM/C1, CCRF/CEM, HL-60, HL-60/MX2. METHODS: Cell viability was assessed by trypan blue staining. The expression of 93 genes involved in the process of apoptosis was determined by real-time PCR method using Taqman Low Density Array (TLDA). RESULTS: CEM/C1, CCRF/CEM, HL-60, HL-60/MX2 cells were exposed to DCA for 24 h. The sensitivity of each cell line to DCA is different and depends on the concentration. CEM/C1 was the most sensitive with an half-maximal inhibitory concentration (IC50) value of 30 mM, while HL-60/MX2 was the most resistant with an IC50 value of 75 mM. Exposure of leukemia cells to DCA causes differences in gene expression profiles which cannot indicate that any particular pathway of apoptosis is initiated. However, the presence of 388 statistically significant correlations between expression pattern of gens was determined. CONCLUSION: We showed that DCA causes a decrease in viability of leukemia cells. The decline depends on DCA concentration. The induction of any particular apoptosis pathway is not shown in cells after DCA treatment. For that reason, studies on the molecular mechanism of cell death after exposure to DCA should be continued.

Influence of metformin, sodium dichloroacetate and their combination on the hematological and biochemical blood parameters of rats with gliomas C6.

BACKGROUND: The efficacy of antimetabolic therapy of malignant neoplasms could not be explained solely by the direct mechanisms of action of such energy metabolism inhibitors as sodium dichloroacetate (DCA) and metformin (MTF). The indirect effects of DCA and MTF on the organs and tissues, which could play significant role in the antitumor activity of these agents, have not been thoroughly explored. AIM: To investigate the effect of MTF, DCA and their combination on the survival of rats with C6 glioma and major haematological and biochemical blood parameters. MATERIALS AND METHODS: DCA and MTF were administered orally to inbred female rats for 11 days starting from the second day after tumor cell transplantation at a total dose of 1.1 and 2.6 g/kg, respectively. When combined treatment was used, MTF was administered 3 hours after the administration of DCA. The content of lactate and pyruvate in blood plasma was determined on the ChemWell® 2910 (Combi) automatic analyzer. Blood parameters were determined using the Particle Counter PCE-210 automatic hematology analyzer. RESULTS: The administration of DCA did not significantly affect the life span of rats with C6 glioma. Duration of life of rats, which were administered with MTF only, was significantly higher (by 19.1%, p < 0.01). Combined administration of DCA + MTF prolonged life span of animals with glioma by 50% (p < 0.001). The positive result of antitumor activity of MTF alone and in combination with DCA correlated with a decrease in the mean platelet volume/platelet count (MPV/PLT) ratio by 75.0% (p < 0.05) compared with tumor control. In addition, the expressed antitumor effect of combination therapy with DCA and MTF was associated with a decrease (p < 0.05) in glucose and lactate levels in blood plasma of rats with C6 glioma by 10% and 41.4%, respectively, compared to tumor control. Analysis of blood parameters showed that the growth of C6 glioma was accompanied by the development of leukopenia, anemia and thrombocytopenia. The introduction of DCA caused the correction of manifestations of anemia and leukopenia, but did not affect the level of platelets in the blood of animals with glioma. MTF alone and in combination with DCA positively influenced the number of white blood cells and caused complete thrombocytopenia correction, increasing platelet count by more than 200% (p < 0.001). CONCLUSION: The ability of MTF either used alone or in combination with DCA to influence the development of C6 glioma which is manifested in an increase in the lifespan of rats has been revealed. The most pronounced antitumor effect was recorded against the background of the combined use of these agents, which may be due to their ability to lower the levels of lactate and glucose in the blood of tumor-bearing rats. It is proved that MTF both in monotherapy and in combination with DCA provides correction of anemia and thrombocytopenia, which arise at the background of glioma C6 growth.

First In Vivo Test of Thermoembolization: Turning Tissue Against Itself Using Transcatheter Chemistry in a Porcine Model.

PURPOSE: Embolotherapies are commonly used for management of primary liver cancer. Explant studies of treated livers, however, reveal an untreated tumor in a high fraction of cases. To improve on this, we propose a new concept referred to as thermoembolization. In this technique, the embolic material reacts in local tissues. Highly localized heat energy is released simultaneously with the generation of acid in the target vascular bed. Combined with ischemia, this should provide a multiplexed attack. We report herein our initial results testing the feasibility of this method in vivo. MATERIALS AND METHODS: Institutional approval was obtained, and three outbred swine were treated in a segmental hepatic artery branch (right or left medial lobe) with thermoembolic material (100, 400, or 500 µL). Solutions (2 or 4 mol/L) of an acid chloride were made using ethiodized oil as the vehicle. Animals were housed overnight, scanned by CT, and euthanized. Necropsy samples of treated tissue were obtained for histologic analysis. RESULTS: All animals survived the procedure. Vascular stasis occurred rapidly in all cases despite the small volumes used. The lower concentration (2 mol/L) penetrated more distally than the 4 mol/L solution. At CT the following day, vascular casts of ethiodized oil were observed, indicating recanalization had not occurred. Histology specimens demonstrated coagulative necrosis centered on the vessel lumen extending for several hundred microns with a peripheral inflammatory infiltrate. CONCLUSIONS: Thermoembolization is a new technique for embolization with initial promise. However, results indicate much work must be done to optimize the technique.

AKT-independent activation of p38 MAP kinase promotes vascular calcification.

Vascular calcification is prevalent in patients with atherosclerosis, and oxidative stress promotes pathogenesis of atherosclerosis. We have previously reported that activation of AKT by oxidative stress induces vascular calcification. Using sodium dichloroacetate (DCA), a previously reported small molecule inhibitor of AKT, the present studies uncovered an AKT-independent mechanism in regulating vascular calcification. We found that DCA dose-dependently induced calcification of vascular smooth muscle cells (VSMC) in vitro and aortic rings ex vivo. Furthermore, DCA markedly enhanced vascular calcification in atherosclerotic ApoE knockout mice in vivo. DCA-induced VSMC calcification was associated with increased Runx2, but not via activation of AKT, a key upstream signal that upregulates Runx2 during VSMC calcification. In contrast, DCA inhibited AKT activation and induced activation of p38 MAPK in calcified atherosclerotic lesions in vivo and calcified VSMC in vitro. Using a pharmacological inhibitor and shRNA for p38 MAPK, we demonstrated that inhibition of p38 MAPK blocked DCA-induced Runx2 upregulation and VSMC calcification. Furthermore, Runx2 deletion attenuated DCA-induced VSMC calcification. Immunoprecipitation analysis revealed association of p38 MAPK with Runx2, which was enhanced by DCA treatment. Knockdown p38 MAPK inhibited DCA-induced Runx2 transactivity, supporting the function of p38 MAPK in regulating Runx2 transactivity. Our studies have uncovered a new function of DCA in regulating vascular calcification, via AKT-independent activation of p38 MAPK. Furthermore, we have identified novel interaction between p38 MAPK and Runx2 enhances Runx2 transactivity, thus promoting VSMC calcification. These results revealed a novel signaling mechanism underlying DCA-induced vascular calcification, and offer opportunities to identify new therapeutic targets.

Dichloroacetate induced intracellular acidification in glioblastoma: in vivo detection using AACID-CEST MRI at 9.4 Tesla.

Intracellular pH (pHi) plays an important role in the maintenance of normal cell function, and is maintained within a narrow range by the activity of transporters located at the plasma membrane. Modulation of tumor pHi may influence proliferation, apoptosis, chemotherapy resistance, and thermosensitivity. Chemical exchange saturation transfer (CEST) is a novel MRI contrast mechanism that is dependent on cellular pH. Amine and amide concentration-independent detection (AACID) is a recently developed CEST contrast method that is intracellular pH (pHi) weighted. Dichloroacetate (DCA) can alter tumor pHi by inhibiting the enzyme pyruvate dehydrogenase kinase causing reduced lactate (increasing pHi), or by decreasing the expression of monocarboxylate transporters and vacuolar ATPase leading to reduced pHi. Since the net in vivo effect of DCA on pHi is difficult to predict, the purpose of this study was to quantify the magnitude of acute pHi change in glioblastoma after a single DCA injection using AACID CEST MRI. Using a 9.4T MRI scanner, CEST spectra were acquired in six mice approximately 14 days after implanting 105 U87 human glioblastoma multiforme (GBM) cells in the brain, before and after intravenous injection of DCA (dose: 200 mg/kg). Three additional mice received only phosphate buffered saline (PBS) injection and were studied as controls. Repeated measures t test was used to compare AACID changes in tumor and contralateral tissue regions of interest. One hour after DCA injection there was a significant increase in tumor AACID level by 0.04 ± 0.01 corresponding to a 0.16 decrease in pHi, and no change in AACID in contralateral tissue. Inspection of AACID maps following PBS injection showed no differences. The use of DCA to induce a tumor specific pH change detectable by AACID CEST MRI is consistent with previous studies that have shown similar effects for lonidamine and topiramate. This study demonstrates that a single dose of DCA can be used as a pharmacological challenge to induced rapid tumor intracellular acidification.

Inhibition of pyruvate dehydrogenase kinase improves pulmonary arterial hypertension in genetically susceptible patients.

Pulmonary arterial hypertension (PAH) is a progressive vascular disease with a high mortality rate. It is characterized by an occlusive vascular remodeling due to a pro-proliferative and antiapoptotic environment in the wall of resistance pulmonary arteries (PAs). Proliferating cells exhibit a cancer-like metabolic switch where mitochondrial glucose oxidation is suppressed, whereas glycolysis is up-regulated as the major source of adenosine triphosphate production. This multifactorial mitochondrial suppression leads to inhibition of apoptosis and downstream signaling promoting proliferation. We report an increase in pyruvate dehydrogenase kinase (PDK), an inhibitor of the mitochondrial enzyme pyruvate dehydrogenase (PDH, the gatekeeping enzyme of glucose oxidation) in the PAs of human PAH compared to healthy lungs. Treatment of explanted human PAH lungs with the PDK inhibitor dichloroacetate (DCA) ex vivo activated PDH and increased mitochondrial respiration. In a 4-month, open-label study, DCA (3 to 6.25 mg/kg b.i.d.) administered to patients with idiopathic PAH (iPAH) already on approved iPAH therapies led to reduction in mean PA pressure and pulmonary vascular resistance and improvement in functional capacity, but with a range of individual responses. Lack of ex vivo and clinical response was associated with the presence of functional variants of SIRT3 and UCP2 that predict reduced protein function. Impaired function of these proteins causes PDK-independent mitochondrial suppression and pulmonary hypertension in mice. This first-in-human trial of a mitochondria-targeting drug in iPAH demonstrates that PDK is a druggable target and offers hemodynamic improvement in genetically susceptible patients, paving the way for novel precision medicine approaches in this disease.

In vivo evaluation of tumour acidosis for assessing the early metabolic response and onset of resistance to dichloroacetate by using magnetic resonance pH imaging.

Dichloroacetate (DCA) can reverse the glycolytic phenotype that is responsible of increased lactate production and extracellular pH acidification in cancer cells. Magnetic resonance imaging-chemical exchange saturation transfer (MRI-CEST) pH mapping is a novel non-invasive imaging approach that can measure in vivo extracellular tumour pH. We examined whether MRI-CEST pH mapping can monitor in vivo changes in tumour acidosis for assessing treatment response to DCA. Cell viability and extracellular pH were assessed in TS/A breast cancer cells treated with 1-10 mM DCA for 24 h in normoxia or hypoxia (1% O2) conditions. Extracellular tumour pH values were measured in vivo by MRI-CEST pH mapping of TS/A tumour-bearing mice before, three days and fifteen days after DCA or saline treatment. Reduced extracellular acidification and vitality were observed in DCA-treated TS/A cells. Tumour-bearing mice showed a marked and significant increase of tumour extracellular pH at 3 days post-DCA treatment, reflecting DCA-induced glycolysis inhibition, as confirmed by reduced lactate production. After 15 days of DCA treatment, the onset of resistance to DCA was observed, with recover of tumour extracellular acidification and lactate levels that returned to baseline values. A significant correlation was observed between tumour extracellular pH values and lactate levels (r= -0.97, P<0.05). These results suggest that MRI-CEST pH imaging is a promising tool to monitor the early response and efficacy of cancer metabolic targeting drugs.

The Effectiveness of Matrix Cauterization With Bichloracetic Acid in the Treatment of Ingrown Toenails.

BACKGROUND: Chemical matricectomy is performed mainly by 2 agents, phenol and sodium hydroxide. Chemical matricectomy with phenol has a low recurrence rate and good cosmetic results, but it produces extensive tissue destruction and can result in drainage and a delayed healing time. These adverse effects have brought forward the use of chemical agents such as sodium hydroxide and trichloroacetic acid for matricectomy. OBJECTIVE: This prospective study aimed mainly to evaluate the efficacy of partial nail avulsion and selective chemical cauterization of the matrix using 90% bichloracetic acid (BCA) in the treatment of the ingrown nails. MATERIALS AND METHODS: A total of 30 patients with 58 ingrown toenail edges were included in this study. All of the patients underwent chemical matricectomy with 90% BCA after partial nail avulsion. Adverse effects such as postoperative pain and drainage were minimal in most of the patients. RESULTS: One patient who underwent matricectomy had recurrence in a single nail edge (1.8%) at the 12th month of the follow-up. No recurrence was observed in 29 patients during mean follow-up period. This was considered to be statistically significant (p < .001). CONCLUSION: This is the first study to use BCA for the treatment of ingrown toenail. Partial nail avulsion followed by BCA matricectomy is a safe, simple, and effective method with low rates of postoperative morbidity and high rates of success. Therefore, partial nail avulsion and BCA matricectomy can be used as an alternative treatment method for the treatment of ingrown toenails.

Therapeutic applications of dichloroacetate and the role of glutathione transferase zeta-1.

Dichloroacetate (DCA) has several therapeutic applications based on its pharmacological property of inhibiting pyruvate dehydrogenase kinase. DCA has been used to treat inherited mitochondrial disorders that result in lactic acidosis, as well as pulmonary hypertension and several different solid tumors, the latter through its ability to reverse the Warburg effect in cancer cells and restore aerobic glycolysis. The main clinically limiting toxicity is reversible peripheral neuropathy. Although administration of high doses to rodents can result in liver cancer, there is no evidence that DCA is a human carcinogen. In all studied species, including humans, DCA has the interesting property of inhibiting its own metabolism upon repeat dosing, resulting in alteration of its pharmacokinetics. The first step in DCA metabolism is conversion to glyoxylate catalyzed by glutathione transferase zeta 1 (GSTZ1), for which DCA is a mechanism-based inactivator. The rate of GSTZ1 inactivation by DCA is influenced by age, GSTZ1 haplotype and cellular concentrations of chloride. The effect of DCA on its own metabolism complicates the selection of an effective dose with minimal side effects.