Resistance to Methotrexate develops due to

Resistance to Methotrexate develops due
to?
a) Rapid Cancer cell multiplication
b) Deficiency of thymidylate kinase
c) Deficiency of thymidylate synthetase
d) Increased production of dihydrofolate reductase
Correct Answer - D
Ans. is ‘d’ i.e., Increased production of dihydrofolate reductase
Methotrexate resistance
o Methotrexate resistance may be due to any of the following
mechanism :?
i) Defective transport into cells
ii) Production of altered form of DHFR that have decreased
affinity for methotrexate
iii) Increased concentrations of intracellular DHFR through gene
amplification or altered gene regulation
iv) Decreased ability to synthesize methotrexate polyglutamates
v) Increased expression of a drug efflux transporter, of the MRP
(multidrug resistance protein) class