Dichloroacetate metabolically targeted therapy defeats cytotoxicity of standard anticancer drugs.
OBJECTIVE
The observation that the orphan drug dichloroacetate (DCA) selectively promotes mitochondria-regulated apoptosis and inhibits tumour growth in preclinical models by shifting the glucose metabolism in cancer cells from anaerobic to aerobic glycolysis attracted not only scientists', clinicians' but also patients' interests and prompted us to further evaluate DCA effects against paediatric malignancies.


METHODS
The effects of DCA on mitochondrial membrane potential (ΔΨm), cell viability and induction of apoptosis were evaluated in paediatric tumour cell lines and the non-malignant cell line HEK293. In addition, combinations of DCA with the standard anticancer drugs cisplatin, doxorubicin, and temozolomide were tested and intra- and extra-cellular platinum species analysed.


RESULTS
DCA selectively induced phosphatidylserine externalisation and reduced ΔΨm in paediatric tumour cells compared to HEK293 cells, but DCA concentrations ≤ 10 mmol/L only moderately inhibited the growth of 18 paediatric tumour cell lines. DCA neither influenced the in vitro stability of cisplatin nor the cellular cisplatin uptake, but it abrogated the cytotoxicity of cisplatin in 7 out of 10 cell lines. DCA also affected the cytotoxicity of doxorubicin but did not influence the cytotoxicity of temozolomide. Despite phosphatidylserine externalisation, DCA failed to activate caspase 3/7 and, moreover, suppressed caspase 3/7 activation by cisplatin and doxorubicin.


CONCLUSIONS
Our results indicate that apart from the intriguing effects of DCA on the glucose metabolism of cancer cells, the use of DCA for cancer treatment has to be evaluated carefully. Moreover, compassionate use of the orally available drug by patients with cancer themselves without medical supervision is strongly discouraged at present.
Heshe
Dirk
D
Department of Paediatric Haematology and Oncology, University Children's Hospital, Muenster, Germany.
Hoogestraat
Stephanie
S
Brauckmann
Christine
C
Karst
Uwe
U
Boos
Joachim
J
Lanvers-Kaminsky
Claudia
C
D000284:Administration, Oral; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival; D002945:Cisplatin / Q000008:administration & dosage; D003606:Dacarbazine / Q000008:administration & dosage / Q000031:analogs & derivatives; D003999:Dichloroacetic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D004317:Doxorubicin / Q000008:administration & dosage; D016503:Drug Delivery Systems; D004347:Drug Interactions; D004355:Drug Stability; D005947:Glucose / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D053078:Membrane Potential, Mitochondrial; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology; D000077204:Temozolomide
D003606:Dacarbazine; D004317:Doxorubicin; D003999:Dichloroacetic Acid; D005947:Glucose; D002945:Cisplatin; D000077204:Temozolomide