pulmicort and Neoplasms

The oxidative pentose phosphate pathway (PPP) contributes to tumour growth, but the precise contribution of 6-phosphogluconate dehydrogenase (6PGD), the third enzyme in this pathway, to tumorigenesis remains unclear. We found that suppression of 6PGD decreased lipogenesis and RNA biosynthesis and elevated ROS levels in cancer cells, attenuating cell proliferation and tumour growth. 6PGD-mediated production of ribulose-5-phosphate (Ru-5-P) inhibits AMPK activation by disrupting the active LKB1 complex, thereby activating acetyl-CoA carboxylase 1 and lipogenesis. Ru-5-P and NADPH are thought to be precursors in RNA biosynthesis and lipogenesis, respectively; thus, our findings provide an additional link between the oxidative PPP and lipogenesis through Ru-5-P-dependent inhibition of LKB1-AMPK signalling. Moreover, we identified and developed 6PGD inhibitors, physcion and its derivative S3, that effectively inhibited 6PGD, cancer cell proliferation and tumour growth in nude mice xenografts without obvious toxicity, suggesting that 6PGD could be an anticancer target.

Topics: AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Humans; Lipogenesis; Neoplasms; Oxidative Stress; Pentose Phosphate Pathway; Phosphogluconate Dehydrogenase; Protein Serine-Threonine Kinases; Ribulosephosphates; Signal Transduction

Chronicles in Drug Discovery features special interest reports on advances in drug discovery and development. This month we focus on the progress of the ongoing search for safe and effective chemopreventive agents. Chemoprevention is a strategy to decrease the risk of developing cancer by using agents that prevent or abrogate carcinogenic processes. Bowman- Birk inhibitor concentrate, budesonide, NCX-4016 and statins are all undergoing investigation in the clinical setting as potential chemopreventive agents for head and neck, lung, colon and breast cancers, respectively.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Anticarcinogenic Agents; Aspirin; Budesonide; Cell Transformation, Neoplastic; Chemoprevention; Clinical Trials as Topic; Drug Evaluation, Preclinical; Glucocorticoids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Neoplasms; Precancerous Conditions; Trypsin Inhibitor, Bowman-Birk Soybean; Trypsin Inhibitors

The identification of self-renewing and multipotent neural stem cells (NSCs) in the mammalian brain holds promise for the treatment of neurological diseases and has yielded new insight into brain cancer. However, the complete repertoire of signaling pathways that governs the proliferation and self-renewal of NSCs, which we refer to as the 'ground state', remains largely uncharacterized. Although the candidate gene approach has uncovered vital pathways in NSC biology, so far only a few highly studied pathways have been investigated. Based on the intimate relationship between NSC self-renewal and neurosphere proliferation, we undertook a chemical genetic screen for inhibitors of neurosphere proliferation in order to probe the operational circuitry of the NSC. The screen recovered small molecules known to affect neurotransmission pathways previously thought to operate primarily in the mature central nervous system; these compounds also had potent inhibitory effects on cultures enriched for brain cancer stem cells. These results suggest that clinically approved neuromodulators may remodel the mature central nervous system and find application in the treatment of brain cancer.

Topics: Animals; Cell Survival; Cells, Cultured; Mice; Molecular Structure; Neoplasms; Neurons; Pharmaceutical Preparations; Sensitivity and Specificity; Stem Cells

The FHIT gene has many hallmarks of a tumor-suppressor gene and is involved in a large variety of cancers. We treated A/J mice and (C57BL/6J x 129/SvJ)F1 (B6/129 F1) mice, either wild-type or FHIT+/-, with multiple doses of benzo[a]pyrene (B[a]P) by gavage. B[a]P caused a time-related increase of micronuclei in peripheral blood erythrocytes. Both A/J and B6/129 F1 mice, irrespective of their FHIT status, were sensitive to induction of forestomach tumors, whereas B[a]P induced glandular stomach hyperplasia and a high multiplicity of lung tumors in A/J mice only. Preneoplastic lesions of the uterus were more frequent in FHIT+/- mice. B6/129 F1 mice underwent spontaneous alopecia areata and hair bulb cell apoptosis, which were greatly accelerated either by FHIT heterozygosity or by B[a]P treatment, thus suggesting that FHIT plays a role in the pathogenesis of alopecia areata. The oral administration of either budesonide or N-acetyl-L-cysteine (NAC) inhibited the occurrence of this inflammatory skin disease. In addition, these agents prevented B[a]P-induced glandular stomach hyperplasia and decreased the size of both forestomach tumors and lung tumors in A/J mice. Budesonide also attenuated lung tumor multiplicity. In B6/129 F1 mice, NAC significantly decreased the proliferating cell nuclear antigen in lung tumors. Both budesonide and NAC inhibited B[a]P-induced forestomach tumors and preneoplastic lesions of the respiratory tract in B6/129 F1 mice. In conclusion, heterozygosity for FHIT affects susceptibility of mice to spontaneous alopecia areata and B[a]P-induced preneoplastic lesions of the uterus and does not alter responsiveness to budesonide and NAC.

Topics: Acetylcysteine; Acid Anhydride Hydrolases; Alopecia Areata; Animals; Anti-Inflammatory Agents; Benzo(a)pyrene; Budesonide; Female; Genes, Tumor Suppressor; Lung; Mice; Mice, Inbred Strains; Neoplasm Proteins; Neoplasms; Stomach