Methods, assays and compounds for treating bacterial infections by inhibiting methylthioinosine phosphorylase

1. A method for treating an infection caused by bacteria that use 5′-methylthioinosine phosphorylase (MTIP) in a quorum sensing pathway comprising administering to a subject having the infection a sub-growth inhibiting amount of a 5′-methylthioinosine phosphorylase (MTIP) inhibitor,

wherein the MTIP inhibitor has an IC50 value less than 50 nanomolar for MTIP,

wherein the MTIP inhibitor has an IC50 value greater than or equal to 50 nanomolar for human purine nucleoside phosphorylase (PNP),

wherein the MTIP inhibitor has an IC50 value greater than or equal to 50 nanomolar for 5′-methylthioadenosine nucleosidase (MTAN), and

wherein the MTIP inhibitor has an IC50 value greater than or equal to 50 nanomolar for 5′-methylthioadenosine phosphorylase (MTAP).

2. The method of claim 1 , wherein the bacteria is Pseudomonas aeruginosa, Pseudomonas syringae or Xanthomonas campestris.

3. The method of claim 1 , wherein the MTIP inhibitor comprises a compound having formula (I):

wherein

A is CH or N;

B is OH;

D is chosen from H, OH, NH 2 , or SCH 3 ;

X and Y are independently selected from H, OH or halogen, except that when one of X and Y is hydroxy or halogen, the other is hydrogen;

Z is selected from CH 2 SQ, CH 2 OQ or Q, where Q is an optionally substituted alkyl, aralkyl, aralkenyl or aryl group, each of which is optionally substituted with one or more substituents selected from hydroxy, halogen, methoxy, amino, carboxy, or straight- or branched-chain C 1 -C 6 alkyl; provided that Q is not CH 2 OH;

or a tautomer thereof; or a pharmaceutically acceptable salt thereof; or an ester thereof; or a prodrug thereof.

4. The method of claim 3 , wherein the MTIP inhibitor comprises a compound having formula (II):

wherein Q is an optionally substituted alkyl, aralkyl or aryl group, each of which is optionally substituted with one or more substituents selected from hydroxy, halogen, methoxy, amino, carboxy, or straight- or branched-chain C 1 -C 6 alkyl;

or a tautomer thereof; or a pharmaceutically acceptable salt thereof, or an ester thereof; or a prodrug thereof.

5. The method of claim 1 , wherein the MTIP inhibitor comprises a compound having formula (III) or formula (IIIa):

wherein

V is CH 2 ;

W is NR 1 ;

X is CH 2 ;

Y is selected from hydrogen, halogen and hydroxyl;

Z is selected from hydrogen, halogen, SQ, OQ and Q, where Q is an optionally substituted alkyl, aralkyl or aryl group, each of which is optionally substituted with one or more substituents selected from hydroxy, halogen, methoxy, amino, carboxy, or straight- or branched-chain C 1 -C 6 alkyl;

R 1 is a radical of the formula (IV)

A is selected from N, CH and CR, where R is selected from halogen or optionally substituted alkyl, aralkyl or aryl group, each of which is optionally substituted with one or more substituents selected from hydroxy, halogen, methoxy, amino, carboxy, or straight- or branched-chain C 1 -C 6 alkyl;

B is OH;

D is selected from OH, NH 2 , SCH 3 and hydrogen;

E is N;

G is CH 2 ;

or a tautomer thereof or a pharmaceutically acceptable salt thereof or an ester thereof.

6. The method of claim 1 , wherein the MTIP inhibitor comprises a compound having formula (VI):

wherein

R 1 is H or NR 3 R 4 ;

R 2 is H or an alkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl group, each of which is optionally substituted with one or more hydroxy, alkoxy, thiol, alkylthio, arylthio, aralkylthio, halogen, carboxylic acid, carboxylate alkyl ester, nitro, or NR 3 R 4 groups, where each alkylthio, arylthio and aralkylthio group is optionally substituted with one or more alkyl, halogen, amino, hydroxy, or alkoxy groups;

provided that when R 1 is H, R 2 is an alkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl group which is substituted with at least one NR 3 R 4 group, and optionally substituted with one or more hydroxy, alkoxy, thiol, alkylthio, arylthio, aralkylthio, halogen, carboxylic acid, carboxylate alkyl ester or nitro group;

R 3 and R 4 , independently of each other, are H or an alkyl, alkenyl, alkynyl, aralkyl, aralkenyl, aralkynyl, or aryl group, each of which is optionally substituted with one or more hydroxy, alkoxy, thiol, alkylthio, arylthio, aralkylthio, halogen, carboxylic acid, carboxylate alkyl ester, nitro, or NR 3 R 4 groups, where each alkylthio, arylthio and aralkylthio group is optionally substituted with one or more alkyl, halogen, amino, hydroxy, or alkoxy groups;

A is N or CH;

B is OH; and

D is H, OH, NH 2 , or SCH 3 ;

or a tautomer thereof, or a pharmaceutically acceptable salt thereof, or an ester prodrug form thereof.

7. The method of claim 1 , wherein the MTIP inhibitor comprises a compound having formula (VII):

wherein

X is an alkyl, cycloalkyl, aralkyl, aralkenyl, alkenyl, alkynyl or aryl group, each of which is optionally substituted with one or more substituents selected from the group consisting of hydroxy, alkoxy, cycloalkyl, thiol, alkylthio, arylthio, aralkylthio, halogen, carboxylic acid, carboxylate alkyl ester, nitro, cyano, thiazole and NR 2 R 3 group, where each alkylthio, arylthio and aralkylthio group is optionally substituted with one or more alkyl, halogen, amino, hydroxy, or alkoxy groups; or X is SR 1 ; or X is NR 2 R 3 ;

R 1 , R 2 and R 3 are independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl or aryl, each of which is optionally substituted with one or more substituents selected from the group consisting of hydroxy, alkoxy, thiol, alkylthio, arylthio, aralkylthio, halogen, carboxylic acid, carboxylate alkyl ester, nitro, cyano and NR 2 R 3 group, where each alkylthio, arylthio and aralkylthio group is optionally substituted with one or more alkyl, halogen, amino, hydroxy, or alkoxy groups;

A is N or CH;

B is OH;

D is H, OH, NH 2 , or SCH 3 ;

provided that X is not CH 2 Z, where Z is selected from OH, hydrogen, halogen, SQ 1 , OQ 2 and Q 3 , where Q 1 is an optionally substituted alkyl, aralkyl or aryl group, Q 2 is an optionally substituted alkyl group and Q 3 is an optionally substituted alkyl group;

or a tautomer thereof, or a pharmaceutically acceptable salt thereof, or an ester prodrug form thereof.

8. The method of claim 1 , wherein the sub-growth inhibiting amount of the MTIP inhibitor inhibits quorum sensing in the bacteria.

9. The method of claim 1 , wherein the MTIP inhibitor has the formula:

wherein A is CH or N; B is OH; D is chosen from H, OH, NH 2 , or SCH 3 ; X is OH; Y is H; and Z is Q, where Q is a methyl group which is substituted with one or more substituents selected from the group consisting of methoxy, amino and carboxy, or Q is an optionally substituted, alkenyl, aralkyl, aralkenyl, aryl group or C 2 -C 10 alkyl group, each of which is optionally substituted with one or more substituents selected from hydroxy, halogen, methoxy, amino, carboxy, or straight- or branched-chain C 1 -C 6 alkyl; or a tautomer thereof; or a pharmaceutically acceptable salt thereof; or an ester thereof.

10. The method of claim 1 , wherein the MTIP inhibitor is selected from the group consisting of:

or a tautomer thereof; or a pharmaceutically acceptable salt thereof; or an ester thereof.

11. The method of claim 1 , wherein the MTIP inhibitor is selected from the group consisting of:

or a tautomer thereof; or a pharmaceutically acceptable salt thereof; or an ester thereof.

12. The method of claim 1 , comprising coadministering the 5′-methylthioinosine phosphorylase (MTIP) inhibitor with 5′-methylthioinosine and/or 5′-methylthioadenosine.