Tumor-selective combination therapy

1. A pharmaceutical composition comprising:

(i) a deoxynyboquinone (DNQ) compound having the formula:

wherein

R 1 , R 2 , R 3 , and R 4 are each independently —H or —X—R;

each X is independently a direct bond or a bridging group, wherein the bridging group is O—, —S—, —NH—, —C(═O)—, —O—C(═O)—, —C(═O)—O—, —O—C(═O)—O—, or a linker of the formula —W-A-W—,

wherein each W is independently N(R′)C(═O)—, —C(═O)N(R′)—, —OC(═O)—, —C(═O)O—, —O—, —S—, —S(O)—, —S(O) 2 —, —N(R′)—, —C(═O)—, —(CH 2 ) n — wherein n is 1-10, or a direct bond, wherein each R′ is independently H, (C 1 -C 6 )alkyl, or a nitrogen protecting group; and

each A is independently (C 1 -C 20 )alkyl, (C 2 -C 18 )alkenyl, (C 2 -C 18 )alkynyl, (C 3 -C 8 )cycloalkyl, (C 8 -C 10 )aryl, (OCH 2 —CH 2 ) n —, wherein n is 1 to 20, C(O)NH(CH 2 ) n — wherein n is 1 to 6, OP(O)(OH)O—, —OP(O)(OH)O(CH 2 ) n — wherein n is 1 to 6, or (C 1 -C 20 )alkyl, (C 2 -C 16 )alkenyl, (C 2 -C 16 )alkynyl, or —(OCH 2 —CH 2 ) n — interrupted between two carbons, or between a carbon and an oxygen, with a cycloalkyl, heterocycle, or aryl group;

each R is independently alkyl, alkenyl, alkynyl, heteroalkyl, cycloalkyl, cycloalkenyl, heterocycloalkyl, heterocycloalkenyl, (cycloalkyl)alkyl, (heterocycloalkyl)alkyl, (cycloalkyl)heteroalkyl, (heterocycloalkyl)heteroalkyl, aryl, heteroaryl, (aryl)alkyl, (heteroaryl)alkyl, hydrogen, hydroxy, hydroxyalkyl, alkoxy, (alkoxy)alkyl, alkenyloxy, alkynyloxy, (cycloalkyl)alkoxy, heterocycloalkyloxy, amino, alkylamino, aminoalkyl, acylamino, arylamino, sulfonylamino, sulfinylamino, COR x , —COOR x , —CONHR x , —NHCOR x , —NHCOOR x , —NHCONHR x , —N 3 , —CN, —NC, —NCO, —NO 2 , —SH, -halo, alkoxycarbonyl, alkylaminocarbonyl, sulfonate, sulfonic acid, alkylsulfonyl, alkylsulfinyl, arylsulfonyl, arylsulfinyl, aminosulfonyl, R x S(O)R y —, R x S(O) 2 R y —, R x C(O)N(R x )R y —, R x SO 2 N(R x )R y —, R x N(R x )C(O)R y —, R x N(R x )SO 2 R y —, R x N(R x )C(O)N(R x )R y —, carboxaldehyde, acyl, acyloxy, —OPO 3 H 2 , —OPO 3 Z 2 where Z is an inorganic cation, or saccharide; wherein each R x is independently H, OH, alkyl or aryl, and each R y is independently a group W;

wherein any alkyl or aryl contains optionally substitution of one or more hydroxy, amino, cyano, nitro, or halo groups;

or a salt or solvate thereof;

(ii) a poly-ADP ribose polymerase (PARP1) inhibitor; and

(iii) a pharmaceutically acceptable diluent, carrier, or excipient,

wherein said composition comprises an effective amount of each of the DNQ compound and the PARP1 inhibitor that yields a synergistic cytotoxic effect against cancer cells.

2. The pharmaceutical composition of claim 1 , wherein the PARP1 inhibitor is selected from the group consisting of AG-014699 (Rucaparib), ABT-888 (Veliparib), BSI-201 (Iniparib), AZD2281 (Olaparib), AG14361 and INO-1001.

3. The pharmaceutical composition of claim 1 , wherein the diluent, excipient, or carrier is water, hydroxypropyl-β-cyclodextrin (HPβCD) or a combination thereof.

4. The pharmaceutical composition of claim 1 , wherein R 1 , R 2 , and R 3 are each methyl, R 4 is not H or methyl.

5. The pharmaceutical composition of claim 1 , wherein R 1 , R 3 , and R 4 are each methyl, the group —X—R of R 2 is not —CH 2 —Oac, or when R 1 , R 3 , and R 4 are each methyl, the R group of R 2 is not acyloxy.

6. The pharmaceutical composition of claim 1 , wherein R 1 , R 2 , R 3 and R 4 are not each H at the same occurrence; or R 1 , R 2 , R 3 and R 4 are not each alkyl at the same occurrence, wherein the alkyl is methyl.

7. The pharmaceutical composition of claim 1 , wherein R 1 , R 2 , R 3 , and R 4 are each a (C 1-20 )alkyl group, a (C 2-20 )alkyl group, a (C 3-20 )alkyl group, a (C 4-20 )alkyl group, a (C 5-20 )alkyl group, or a (C 10-20 )alkyl group.

8. The pharmaceutical composition of claim 1 , wherein the DNQ compound has the structure:

or a salt or solvate thereof.

9. A pharmaceutical composition comprising a DNQ compound having the structure:

or a salt or solvate thereof, and a PARP inhibitor, wherein said composition comprises an effective amount of each of the DNQ compound and the PARP1 inhibitor that yields a synergistic cytotoxic effect against cancer cells.

10. The pharmaceutical composition of claim 9 , wherein the PARP inhibitor is selected from the group consisting of AG-014699 (Rucaparib), ABT-888 (Veliparib), BSI-201 (Iniparib), AZD2281 (Olaparib), AG14361 and INO-1001.