Myself and a few others here on PR use dichloroacetate (because of Naviaux et al.)
Today I decided to do a Pubmed search on DCA (dichloroacetate) and mTOR. I found the following which qualifies as very interesting from my perspective.
Overexpression of pyruvate dehydrogenase kinase supports dichloroacetate as a candidate for cutaneous melanoma therapy.
Abstract
OBJECTIVE:
We aimed to verify if there is evidence to consider dichloroacetate (DCA), which inhibits the pyruvate dehydrogenase kinase (PDK) and reverts the metabolic shift of cancer cells from glycolysis to oxidative phosphorylation, as a promising drug for therapy of cutaneous melanoma (CM) patients.
RESEARCH DESIGN AND METHODS:
We assessed the expression profile of PDK 1, 2 and 3 in a series of melanoma samples, to verify if melanoma tumors express the DCA targets, if this expression correlates with the activation of important signaling cascades for melanomagenesis and also with the prognosis of melanoma patients. We also established the sensitivity of melanoma cell lines to DCA treatment, by assessing their metabolic alterations, proliferation and survival.
RESULTS:
We observed that both PDK 1 and 2 isoforms are overexpressed in CM compared to nevi, this expression being associated with the expression of the mTOR pathway effectors and independent of the BRAF mutational status.
Melanoma cell lines treated with DCA showed a shift in metabolism, that is, a decrease in glucose consumption and lactate production, downregulation of proliferation, an increase of apoptosis and a decrease in mTOR pathway activation.
CONCLUSION:
Our results suggest that PDK expression may play a role in melanoma development and that DCA can be useful for CM therapy, alone or in combination with mTOR inhibitors.
Dichloroacetate induces protective autophagy in esophageal squamous carcinoma cells
Abstract
Dichloroacetate (DCA) is an inhibitor of pyruvate dehydrogenase kinase, which promotes the flux of carbohydrates into mitochondria and enhances the aerobic oxidation of glucose. DCA has previously been demonstrated to exhibit antitumor properties. The present study revealed that treatment with DCA induced increased levels of autophagy-associated proteins in esophageal squamous carcinoma cells while minimally affecting apoptosis. The present study examined the localization of light chain (LC)-3 by adenovirus infection with a green fluorescent protein (FP)-red FP-LC3 reporter construction and confirmed that DCA treatment induced significant autophagy. Furthermore, the inhibition of DCA-induced autophagy facilitated cell apoptosis and improved the drug sensitivity of esophageal squamous carcinoma cells to DCA and 5-FU (5-fluorouracil). The proliferation of TE-1 cells was markedly inhibited at low concentrations of DCA and 5-FU treatment when subjected to Atg5 mRNA interference, indicating that autophagy performed a protective role in cell survival upon DCA treatment. To determine the underlying mechanism of DCA-induced autophagy, the present study measured alterations in autophagy-associated signaling pathways.
Notably, the protein kinase B (Akt)-mechanistic target of rapamycin (mTOR) signaling pathway, an important negative regulator of autophagy, was demonstrated to be suppressed by DCA treatment. These results may direct the development of novel strategies for the treatment of esophageal squamous carcinoma based on the combined use of DCA and autophagy inhibitors.
Dichloroacetate induces autophagy in colorectal cancer cells and tumours
Abstract
BACKGROUND:
Dichloroacetate (DCA) has been found to have antitumour properties.
METHODS:
We investigated the cellular and metabolic responses to DCA treatment and recovery in human colorectal (HT29, HCT116 WT and HCT116 Bax-ko), prostate carcinoma cells (PC3) and HT29 xenografts by flow cytometry, western blotting, electron microscopy, (1)H and hyperpolarised (13)C-magnetic resonance spectroscopy.
RESULTS:
Increased expression of the autophagy markers LC3B II was observed following DCA treatment both in vitro and in vivo. We observed increased production of reactive oxygen species (ROS) and mTOR inhibition (decreased pS6 ribosomal protein and p4E-BP1 expression) as well as increased expression of MCT1 following DCA treatment. Steady-state lactate excretion and the apparent hyperpolarised [1-(13)C] pyruvate-to-lactate exchange rate (k(PL)) were decreased in DCA-treated cells, along with increased NAD(+)/NADH ratios and NAD(+). Steady-state lactate excretion and k(PL) returned to, or exceeded, control levels in cells recovered from DCA treatment, accompanied by increased NAD(+) and NADH. Reduced k(PL) with DCA treatment was found in HT29 tumour xenografts in vivo.
CONCLUSIONS:
DCA induces autophagy in cancer cells accompanied by ROS production and mTOR inhibition, reduced lactate excretion, reduced k(PL) and increased NAD(+)/NADH ratio. The observed cellular and metabolic changes recover on cessation of treatment.
Dichloroacetate induces protective autophagy in LoVo cells: involvement of cathepsin D/thioredoxin-like protein 1 and Akt-mTOR-mediated signaling
Abstract
Dichloroacetate (DCA) is an inhibitor of pyruvate dehydrogenase kinase (PDK), and recently it has been shown as a promising nontoxic antineoplastic agent. In this study, we demonstrated that DCA could induce autophagy in LoVo cells, which were confirmed by the formation of autophagosomes, appearance of punctate patterns of LC3 immunoreactivity and activation of autophagy associated proteins. Moreover, autophagy inhibition by 3-methyladenine (3-MA) or Atg7 siRNA treatment can significantly enhance DCA-induced apoptosis. To determine the underlying mechanism of DCA-induced autophagy, target identification using drug affinity responsive target stability (DARTS) coupled with ESI-Q-TOF MS/MS analysis were utilized to profile differentially expressed proteins between control and DCA-treated LoVo cells. As a result, Cathepsin D (CTSD) and thioredoxin-like protein 1 (TXNL1) were identified with significant alterations compared with control. Further study indicated that DCA treatment significantly promoted abnormal reactive oxygen species (ROS) production. On the other hand, DCA-triggered autophagy could be attenuated by N-acetyl cysteine (NAC), a ROS inhibitor.
Finally, we demonstrated that the Akt-mTOR signaling pathway, a major negative regulator of autophagy, was suppressed by DCA treatment. To our knowledge, it was the first study to show that DCA induced protective autophagy in LoVo cells, and the potential mechanisms were involved in ROS imbalance and Akt-mTOR signaling pathway suppression.
My observations:
- dichloroacetate is a good candidate drug to deal with Naviaux's hypometabolic state
- it appears that dichloroacetate also inhibits mTOR
- if mTOR inhibition is desirable as a treatment for SEID, then dichloroacetate would be truly a magic drug!
