Dichloracetate – back to basic (sic)

DR. WEEKS COMMENT:

Alkaline (basic) environments are inhospitable to cancer cells. Dichloracetate is a well researched, well-published oral anti-cancer agent which merits more attention.

the following from www.thedcasite.com

Dichloroacetate induces apoptosis in endometrial cancer cells.

link to full text

1: Gynecol Oncol. 2008 Apr 16 [Epub ahead of print]
Wong JY, Huggins GS, Debidda M, Munshi NC, De Vivo I.
Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston Massachusetts, USA.

PURPOSE: A recent landmark study demonstrated that Dichloroacetate (DCA) treatment promoted apoptosis in lung, breast, and glioblastoma cancer cell lines by shifting metabolism from aerobic glycolysis to glucose oxidation coupled with NFAT-Kv1.5 axis remodeling. The objective of this study was to determine whether DCA induces apoptosis in endometrial cancer cells and to assess apoptotic mechanism. METHODS: A panel of endometrial cancer cell lines with varying degrees of differentiation was treated with DCA and analyzed for apoptosis via flow cytometry. Biological correlates such as gene expression, intracellular Ca(2+), and mitochondrial membrane potential were examined to assess apoptotic mechanism. RESULTS: Initiation of apoptosis was observed in five low to moderately invasive cancer cell lines including Ishikawa, RL95-2, KLE, AN3CA, and SKUT1B while treatment had no effect on non-cancerous 293T cells. Two highly invasive endometrial adenocarcinoma cell lines, HEC1A and HEC1B, were found to be resistant to DCA-induced apoptosis. Apoptotic responding cell lines had a significant increase in early and late apoptotis, a decrease in mitochondrial membrane potential, and decreased Survivin transcript abundance, which are consistent with a mitochondrial-regulated mechanism. DCA treatment decreased intracellular calcium levels in most apoptotic responding cell lines which suggests a contribution from the NFAT-Kv1.5-mediated pathway. DCA treatment increased p53 upregulated modulator of apoptosis (PUMA) transcripts in cell lines with an apoptotic response, suggesting involvement of a p53-PUMA-mediated mechanism. CONCLUSIONS: Dichloroacetate effectively sensitizes most endometrial cancer cell lines to apoptosis via mitochondrial, NFAT-Kv1.5, and PUMA-mediated mechanisms. Further investigation of the cancer therapeutic potential of DCA is warranted.

PMID: 18423823 [PubMed – as supplied by publisher]
link to PubMed summary.

Their website: http://devivo.bwh.harvard.edu/devivo.htm


Dichloroacetate (DCA) Sensitizes Both Wild-Type and Over Expressing Bcl-2 Prostate Cancer Cells In Vitro to Radiation

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Wengang Cao,1,3 Saif Yacoub,1,3 Kathleen T. Shiverick,2,3
Kazunori Namiki,1,3 Yoshihisa Sakai,1,3 Stacy Porvasnik,1,3
Cydney Urbanek,1,3 and Charles J. Rosser1,2,3*
1Department of Urology,University of Florida,Gainesville, Florida
2Department of Pharmacologyand Therapeutics,University of Florida,Gainesville, Florida
3Prostate CancerTranslationalWorking Group,University of Florida,Gainesville, Florida
BACKGROUND. Bcl-2 protects cells from apoptosis and provides a survival advantage to cells
over-expressing this oncogene. In addition, over expression of Bcl-2 renders cell resistant to
radiation therapy. Recently, dichloroacetate (DCA) was proven to potentiate the apoptotic
machinery by interacting with Bcl-2. In this study,we investigated whether treating human prostate
cancer cells with DCA could modulate Bcl-2 expression and if the modulation in Bcl-2 expression
could render the Bcl-2 over expressing cells more susceptible to cytotoxicity effects of radiation.METHODS. PC-3-Bcl-2 and PC-3-Neo human prostate cancer cells treated with DCA in addition
to irradiation were analyzed in vitro for changes in proliferation, clonogenic survival, apoptosis, cell
cycle phase distribution, mitochondrial membrane potential, and expression of Bcl-2, Bcl-xL, Bax, or
Bak proteins.RESULTS. DCA alone produced significant cytotoxic effects and was associated with G1 cell cycle
arrest. Furthermore, DCA was associated with an increased rate of apoptosis. The combination of
DCA with irradiation sensitized both cell lines to radiation’s killing effects. Treatment of PC-3 Bcl-2
or PC-3-Neo with DCA and irradiation resulted in marked changes in various members of the Bcl-2
family. In addition, DCA therapy resulted in a significant change in mitochondria membrane
potential, thus supporting the notion that DCAs effect is on the mitochondria.

CONCLUSIONS. This is the first study to demonstrate DCA can effectively sensitize wild-type
and over expressing Bcl-2 human prostate cancer cells to radiation by modulating the expression
of key members of the Bcl-2 family. Together, these findings warrant further evaluation of the
combination of DCA and irradiation. Prostate #2008 Wiley-Liss, Inc.

KEY WORDS: dichloracetate; radiation; prostate cancer; Bcl-2


Pyruvate kinase M2 is a phosphotyrosine-binding protein

Heather R. Christofk, Matthew G. Vander Heiden, Ning Wu, John M. Asara & Lewis C. Cantley

Growth factors stimulate cells to take up excess nutrients and to use them for anabolic processes. The biochemical mechanism by which this is accomplished is not fully understood but it is initiated by phosphorylation of signalling proteins on tyrosine residues. Using a novel proteomic screen for phosphotyrosine-binding proteins, we have made the observation that an enzyme involved in glycolysis, the human M2 (fetal) isoform of pyruvate kinase (PKM2), binds directly and selectively to tyrosine-phosphorylated peptides. We show that binding of phosphotyrosine peptides to PKM2 results in release of the allosteric activator fructose-1,6-bisphosphate, leading to inhibition of PKM2 enzymatic activity. We also provide evidence that this regulation of PKM2 by phosphotyrosine signalling diverts glucose metabolites from energy production to anabolic processes when cells are stimulated by certain growth factors. Collectively, our results indicate that expression of this phosphotyrosine-binding form of pyruvate kinase is critical for rapid growth in cancer cells. Vol 452| 13 March 2008| doi:10.1038/nature06667

link to the full text Nature article ——- If the link fails, click here.


The M2 splice isoform of pyruvate kinase is important for cancer metabolism and tumour growth

Heather R. Christofk, Matthew G. Vander Heiden, Marian H. Harris, Arvind Ramanathan,
Robert E. Gerszten, Ru Wei, Mark D. Fleming, Stuart L. Schreiber & Lewis C. Cantley

Vol 452| 13 March 2008| doi:10.1038/nature06734

Many tumour cells have elevated rates of glucose uptake but reduced rates of oxidative phosphorylation. This persistence of high lactate production by tumours in the presence of oxygen known as aerobic glycolysis, was first noted by Otto Warburg more than 75 yr ago1. How tumour cells establish this altered metabolic phenotype and whether it is essential for tumorigenesis is as yet unknown. Here we show that a single switch in a splice isoform of the glycolytic enzyme pyruvate kinase is necessary for the shift in cellular metabolism to aerobic glycolysis and that this promotes tumorigenesis. Tumour cells have been shown to express exclusively the embryonic M2 isoform of pyruvate kinase2. Here we use short hairpin RNA to knockdown pyruvate kinase M2 expression in human cancer cell lines and replace it with pyruvate kinase M1. Switching pyruvate kinase expression to the M1 (adult) isoform leads to reversal of the Warburg effect, as judged by reduced lactate production and increased oxygen consumption, and this correlates with a reduced ability to form tumours in nude mouse xenografts. These results demonstrate that M2 expression is necessary for aerobic glycolysis and that this metabolic phenotype provides a selective growth advantage for tumour cells in vivo.

Link to full text letter ———- if the link fails, click here


Dichloroacetate (DCA) as a potential metabolic-targeting
therapy for cancer

ED Michelakis*,1, L Webster1 and JR Mackey2
1Department of Medicine, University of Alberta, Edmonton, Canada; 2Department of Oncology, University of Alberta, Edmonton, Canada

The unique metabolism of most solid tumours (aerobic glycolysis, i.e., Warburg effect) is not only the basis of diagnosing cancer with metabolic imaging but might also be associated with the resistance to apoptosis that characterises cancer. The glycolytic phenotype in cancer appears to be the common denominator of diverse molecular abnormalities in cancer and may be associated with a
(potentially reversible) suppression of mitochondrial function. The generic drug dichloroacetate is an orally available small molecule that, by inhibiting the pyruvate dehydrogenase kinase, increases the flux of pyruvate into the mitochondria, promoting glucose oxidation over glycolysis. This reverses the suppressed mitochondrial apoptosis in cancer and results in suppression of tumour growth in vitro and in vivo. Here, we review the scientific and clinical rationale supporting the rapid translation of this promising metabolic modulator in early-phase cancer clinical trials.

British Journal of Cancer advance online publication, 2 September 2008; doi:10.1038/sj.bjc.6604554 www.bjcancer.com& 2008 Cancer Research UK

http://www.nature.com/bjc/journal/vaop/ncurrent/full/6604554a.html

(note: DCA is already being used clinically. For example, The Medicor Cancer Centres in Toronto uses DCA, along with a ChemoFit test to help determine potential sensitivity of the cancer to DCA)

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DR. WEEKS COMMENT: Alkaline (basic) environments are inhospitable to cancer cells. Dichloracetate is a well researched, well-published oral anti-cancer agent which merits more attention. the following from www.thedcasite.com Dichloroacetate induces apoptosis in endometrial cancer cells. link to full text 1: Gynecol Oncol. 2008 Apr 16 [Epub ahead of print] Wong JY, Huggins GS, Debidda M,…
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