Given an abstract from a research paper, your task is to identify and label relationships between chemical compounds and genes mentioned in the abstract.

The relationship type must be one of ['DOWNREGULATOR', 'SUBSTRATE', 'INDIRECT-REGULATOR', 'PART-OF', 'MODULATOR-ACTIVATOR', 'REGULATOR', 'INHIBITOR', 'COFACTOR', 'UPREGULATOR', 'ACTIVATOR', 'ANTAGONIST', 'NOT', 'INDIRECT-DOWNREGULATOR', 'SUBSTRATE_PRODUCT-OF', 'INDIRECT-UPREGULATOR', 'AGONIST', 'PRODUCT-OF', 'MODULATOR', 'DIRECT-REGULATOR', 'UNDEFINED', 'AGONIST-INHIBITOR', 'AGONIST-ACTIVATOR', 'MODULATOR-INHIBITOR'].

Please format your output as a JSON array. Each entry in the array should express a single relation, formatted as ["<Entity_A>", "<RELATION_A_B>", "<Entity_B>"]. If no relations can be found, please output an empty JSON array [].

Abstract:

Gemcitabine and pemetrexed disodium combinations in vitro and in vivo. Pemetrexed disodium (ALIMTA) is a novel antimetabolite that inhibits at least three folate-dependent enzymes, thymidylate synthase, dihydrofolate reductase, and glycinamide ribonucleotide formyltransferase. Pemetrexed disodium is broadly active in a wide variety of solid tumours, including non-small cell lung, breast, bladder, head and neck and ovarian cancers. Gemcitabine is a broadly active pyrimidine nucleoside antimetabolite, which is approved for the treatment of pancreatic and non-small cell lung cancers. Three preclinical studies have been reported that show cytotoxic synergy between gemcitabine and pemetrexed. Clinical activity with this combination has been observed in a phase I study, with partial responses in three of five patients previously treated for non-small cell lung cancer. An international phase II study of this combination in non-small cell lung cancer is ongoing.
[["Pemetrexed disodium", "INHIBITOR", "dihydrofolate reductase"], ["ALIMTA", "INHIBITOR", "glycinamide ribonucleotide formyltransferase"], ["Pemetrexed disodium", "INHIBITOR", "glycinamide ribonucleotide formyltransferase"], ["Pemetrexed disodium", "INHIBITOR", "thymidylate synthase"], ["ALIMTA", "INHIBITOR", "thymidylate synthase"], ["ALIMTA", "INHIBITOR", "dihydrofolate reductase"]]