Adoptive T cell therapy (ACT) produces durable responses in some cancer patients; however, most tumors are refractory to ACT and the molecular mechanisms underlying resistance are unclear. Using two independent approaches, we identified tumor glycolysis as a pathway associated with immune resistance in melanoma. Glycolysis-related genes were upregulated in melanoma and lung cancer patient samples poorly infiltrated by T cells. Overexpression of glycolysis-related molecules impaired T cell killing of tumor cells, whereas inhibition of glycolysis enhanced T cell-mediated antitumor immunity in vitro and in vivo. Moreover, glycolysis-related gene expression was higher in melanoma tissues from ACT-refractory patients, and tumor cells derived from these patients exhibited higher glycolytic activity. We identified reduced levels of IRF1 and CXCL10 immunostimulatory molecules in highly glycolytic melanoma cells. Our findings demonstrate that tumor glycolysis is associated with the efficacy of ACT and identify the glycolysis pathway as a candidate target for combinatorial therapeutic intervention.
Elevated circulating estrogen levels are associated with increased risk of breast cancer in obese postmenopausal women. Following menopause, the biosynthesis of estrogens through CYP19 (aromatase)-mediated metabolism of androgen precursors occurs primarily in adipose tissue, and the resulting estrogens are then secreted into the systemic circulation. The potential links between obesity, inflammation, and aromatase expression are unknown. In both dietary and genetic models of obesity, we observed necrotic adipocytes surrounded by macrophages forming crown-like structures (CLS) in the mammary glands and visceral fat. The presence of CLS was associated with activation of NF-kB and increased levels of proinflammatory mediators (TNF-a, IL-1b, Cox-2), which were paralleled by elevated levels of aromatase expression and activity in the mammary gland and visceral fat of obese mice. Analyses of the stromalvascular and adipocyte fractions of the mammary gland suggested that macrophage-derived proinflammatory mediators induced aromatase and estrogen-dependent gene expression (PR, pS2) in adipocytes. Saturated fatty acids, which have been linked to obesity-related inflammation, stimulated NF-kB activity in macrophages leading to increased levels of TNF-a, IL-1b, and Cox-2, each of which contributed to the induction of aromatase in preadipocytes. The discovery of the obesity ! inflammation ! aromatase axis in the mammary gland and visceral fat and its association with CLS may provide insight into mechanisms underlying the increased risk of hormone receptor-positive breast cancer in obese postmenopausal women, the reduced efficacy of aromatase inhibitors in the treatment of breast cancer in these women, and their generally worse outcomes. The presence of CLS may be a biomarker of increased breast cancer risk or poor prognosis.
The class of steroid-like compounds designated cardiac glycosides includes well-known drugs such as digoxin, digitoxin, and ouabain. Their continued efficacy in treatment of congestive heart failure and as anti-arrhythmic agents is well appreciated. Less well known, however, is the emerging role of this category of compounds in the prevention and/or treatment of proliferative diseases such as cancer. New findings within the past five years have revealed these compounds to be involved in complex cell-signal transduction mechanisms, resulting in selective control of human tumor but not normal cellular proliferation. As such, they represent a promising form of targeted cancer chemotherapy. New clinical studies of their anticancer potential as single or adjuvant treatments may provide insight into these potentially valuable therapeutic options. This review focuses on recent findings on cellular pharmacology of cardiac glycosides as they relate to treatment of human cancer and attempts to explain why these agents have been overlooked in the past.
Histone modifications, such as the frequently occurring lysine succinylation1,2, are central to the regulation of chromatin-based processes. However, the mechanism and functional consequences of histone succinylation are unknown. Here we show that the α-ketoglutarate dehydrogenase (α-KGDH) complex is localized in the nucleus in human cell lines and binds to lysine acetyltransferase 2A (KAT2A, also known as GCN5) in the promoter regions of genes. We show that succinyl-coenzyme A (succinyl-CoA) binds to KAT2A. The crystal structure of the catalytic domain of KAT2A in complex with succinyl-CoA at 2.3 Å resolution shows that succinyl-CoA binds to a deep cleft of KAT2A with the succinyl moiety pointing towards the end of a flexible loop 3, which adopts different structural conformations in succinyl-CoA-bound and acetyl-CoA-bound forms. Site-directed mutagenesis indicates that tyrosine 645 in this loop has an important role in the selective binding of succinyl- CoA over acetyl-CoA. KAT2A acts as a succinyltransferase and succinylates histone H3 on lysine 79, with a maximum frequency around the transcription start sites of genes. Preventing the α-KGDH complex from entering the nucleus, or expression of KAT2A(Tyr645Ala), reduces gene expression and inhibits tumour cell proliferation and tumour growth. These findings reveal an important mechanism of histone modification and demonstrate that local generation of succinyl-CoA by the nuclear α-KGDH complex coupled with the succinyltransferase activity of KAT2A is instrumental in histone succinylation, tumour cell proliferation, and tumour development.
Objective To investigate the molecular mechanisms of CCL13/monocyte chemoattractant protein 4 (MCP‐4) chemokine expression through proinflammatory cytokines in different primary human fibroblasts and the contribution of CCL13 to monocyte migration. Methods Using RNase protection assays and enzyme‐linked immunosorbent assays, we quantified the expression of CCL13 compared with that of CCL2/MCP‐1 in primary human fibroblasts. Boyden chamber assays were performed to determine the importance of CCL13 for migration of primary monocytes. Pharmacologic inhibitors as well as small interfering RNA knockdown approaches were used to investigate the signaling pathways regulating CCL13 expression. Results The interleukin‐6 (IL‐6)–type cytokine oncostatin M (OSM) was a powerful inducer of CCL13 expression in primary synovial fibroblasts from patients with rheumatoid arthritis (RA) as well as those from healthy control subjects but not in other types of fibroblasts. Neither IL‐6 nor tumor necrosis factor α could stimulate the expression of CCL13 in synovial fibroblasts; IL‐1β was a very weak inducer. Synovial fibroblasts from patients with RA constitutively produced low amounts of CCL13, which was partially dependent on constitutive production of OSM. By investigating the underlying molecular mechanism, we identified STAT‐5, ERK‐1/2, and p38 as critical factors involved in OSM‐dependent transcription and messenger RNA stabilization of CCL13. Conclusion In contrast to other prominent cytokines involved in the pathogenesis of RA, OSM can strongly up‐regulate the expression of CCL13, a chemokine recently identified in the synovial fluid of patients with RA. Despite potent OSM‐induced signal transduction in all types of fibroblasts analyzed, only synovial fibroblasts secreted CCL13, which might be indicative of tissue‐specific imprinting of different fibroblasts during development.
Acupuncture is an appropriate adjunctive treatment for chemotherapy-induced nausea/vomiting, but additional studies are needed. For other symptoms, efficacy remains undetermined owing to high ROB among studies. Future research should focus on standardizing comparison groups and treatment methods, be at least single-blinded, assess biologic mechanisms, have adequate statistical power, and involve multiple acupuncturists.
Purpose: Selective cyclooxygenase-2 (COX-2) inhibitors may suppress carcinogenesis by both COX-2-dependent and COX-2-independent mechanisms. The primary purpose of this study was to evaluate whether celecoxib or rofecoxib, two widely used selective COX-2 inhibitors, possess COX-2-independent antitumor activity.Experimental Design: PC3 and LNCaP human prostate cancer cell lines were used to investigate the growth inhibitory effects of selective COX-2 inhibitors in vitro. To complement these studies, we evaluated the effect of celecoxib on the growth of PC3 xenografts.Results: COX-1 but not COX-2 was detected in PC3 and LNCaP cells. Clinically achievable concentrations (2.5-5.0 Mmol/L) of celecoxib inhibited the growth of both cell lines in vitro, whereas rofecoxib had no effect over the same concentration range. Celecoxib inhibited cell growth by inducing a G 1 cell cycle block and reducing DNA synthesis. Treatment with celecoxib also led to dosedependent inhibition of PC3 xenograft growth without causing a reduction in intratumor prostaglandin E 2 . Inhibition of tumor growth occurred at concentrations (2.37-5.70 Mmol/L) of celecoxib in plasma that were comparable with the concentrations required to inhibit cell growth in vitro. The highest dose of celecoxib led to a 52% reduction in tumor volume and an f50% decrease in both cell proliferation and microvessel density. Treatment with celecoxib caused a marked decrease in amounts of cyclin D1 both in vitro and in vivo.Conclusions: Two clinically available selective COX-2 inhibitors possess different COX-2-independent anticancer properties. The anticancer activity of celecoxib may reflect COX-2-independent in addition to COX-2-dependent effects.
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