Prognostic tools to predict the efficacy of drug treatment targeting chromatin DNA or enzymes acting on DNA
Disclosed are methods of predicting cell response to drug-based therapy using both PCR-Stop assays and real time PCR assays. Methods herein may be used for assessment of drug effect, evaluation of regimen suitability for a given patient, and/or for determination of an optimal drug dose. Also provided are isolated oligonucleotide primers such as primers capable of annealing under PCR conditions to a segment of a c-myc locus, where the primers may be used in the disclosed methods. Further disclosed are kits and systems that may be used for predicting a cell response to drug-based therapy.
1. A method of predicting a response to drug-based therapy comprising;
exposing cancer cells to at least one Histone Deacetylase Inhibitor (HDACi) drug and thereafter at least one anticancer drug;
mixing
(i) DNA extracted from said cancer cells, and
(ii) a primer pair comprising a forward primer and a reverse primer that target a c-myc promoter sequence, wherein at least one of the primers comprises an oligonucleotide primer having at least 95% identity to a nucleotide sequence selected from the group consisting of SEQ ID NO: 1 and SEQ ID NO: 2;
amplifying the DNA in a PCR Stop assay, under conditions to allow production of an amplicon; and
quantifying an amount of accumulated PCR amplified product using real time PCR, wherein the amount of PCR amplified product is inversely proportional to incidence of DNA breaks in an amplified region.
2. The method of claim 1 , wherein the at least one HDACi is selected from the group consisting of hydroxamic acid, cyclic peptides, benzamide and short-chain fatty acids.
3. The method of claim 1 , wherein the at least one HDACi is selected from the group consisting of trichostatin A (TSA), vorinostat (SAHA), sodium butyrate, phenylbutyrate, Valproic acid, Tributyrin, Depsipeptide, MS-275, CI994, and CBHA.
4. The method of claim 1 , wherein the at least one anticancer drug comprises at least one drug selected from the group consisting of intra and inter cross-linking agents, Topoisomerase 1 inhibitors, Topoisomerase 2 inhibitors, alkylating agents, and antimetabolites.
5. The method of claim 1 , wherein the at least one anticancer drug comprises at least one drug selected from the group consisting of etoposide (VP-16), Ara-C, ellipticine, doxorubicin, and cisplatin.
6. The method of claim 1 , wherein the cancer cells comprise cancer cells selected from the group consisting of RKO (colon cancer) cells, MCF-7 (breast cancer) cells, U118 (glioblastoma) cells, and D54 (brain cancer) cells.
7. The method of claim 1 , wherein the PCR amplified product is quantified using real time PCR by identifying a cycle number at which reporter dye emission intensities rise above background noise, where a higher cycle number corresponds to a higher incidence of DNA breaks.
8. The method of claim 7 , wherein the reporter dye comprises an SYBR® green dye.