Project description:Analyses of Resected Human Brain Metastases of Breast Cancer Reveal the Association between Up-Regulation of Hexokinase 2 and Poor Prognosis. Brain metastases of breast cancer seem to be increasing in incidence as systemic therapy improves. Metastatic disease in the brain is associated with high morbidity and mortality. We present the first gene expression analysis of laser-captured epithelial cells from resected human brain metastases of breast cancer compared with unlinked primary breast tumors. The tumors were matched for histology, tumor-node-metastasis (TNM) stage, and hormone receptor status. Most differentially expressed genes were down-regulated in the brain metastases, which included, surprisingly, many genes associated with metastasis. Quantitative real-time PCR analysis confirmed statistically significant differences or strong trends in the expression of six genes: BMP1, PEDF, LAMγ3, SIAH, STHMN3, and TSPD2. Hexokinase 2 (HK2) was also of interest because of its increased expression in brain metastases. HK2 is important in glucose metabolism and apoptosis. In agreement with our microarray results, HK2 levels (both mRNA and protein) were elevated in a brain metastatic derivative (231-BR) of the human breast carcinoma cell line MDA-MB-231 relative to the parental cell line (231-P) in vitro. Knockdown of HK2 expression in 231-BR cells using short hairpin RNA reduced cell proliferation when cultures were maintained in glucose-limiting conditions. Finally, HK2 expression was analyzed in a cohort of 123 resected brain metastases of breast cancer. High HK2 expression was significantly associated with poor patient survival after craniotomy (P = 0.028). The data suggest that HK2 overexpression is associated with metastasis to the brain in breast cancer and it may be a therapeutic target. Common reference design, disease state design.
Project description:Analyses of Resected Human Brain Metastases of Breast Cancer Reveal the Association between Up-Regulation of Hexokinase 2 and Poor Prognosis. Brain metastases of breast cancer seem to be increasing in incidence as systemic therapy improves. Metastatic disease in the brain is associated with high morbidity and mortality. We present the first gene expression analysis of laser-captured epithelial cells from resected human brain metastases of breast cancer compared with unlinked primary breast tumors. The tumors were matched for histology, tumor-node-metastasis (TNM) stage, and hormone receptor status. Most differentially expressed genes were down-regulated in the brain metastases, which included, surprisingly, many genes associated with metastasis. Quantitative real-time PCR analysis confirmed statistically significant differences or strong trends in the expression of six genes: BMP1, PEDF, LAMγ3, SIAH, STHMN3, and TSPD2. Hexokinase 2 (HK2) was also of interest because of its increased expression in brain metastases. HK2 is important in glucose metabolism and apoptosis. In agreement with our microarray results, HK2 levels (both mRNA and protein) were elevated in a brain metastatic derivative (231-BR) of the human breast carcinoma cell line MDA-MB-231 relative to the parental cell line (231-P) in vitro. Knockdown of HK2 expression in 231-BR cells using short hairpin RNA reduced cell proliferation when cultures were maintained in glucose-limiting conditions. Finally, HK2 expression was analyzed in a cohort of 123 resected brain metastases of breast cancer. High HK2 expression was significantly associated with poor patient survival after craniotomy (P = 0.028). The data suggest that HK2 overexpression is associated with metastasis to the brain in breast cancer and it may be a therapeutic target.
Project description:Purpose: In this study, we compared transcriptome profiling (RNA-seq) between normal mouse embryonic stem cell (E14) and Hexokinase2 (Hk2)/ Pyruvate Kinase M2 (Pkm2) overexpressed E14 cell. Result: Using an optimized data analysis workflow, we mapped over 4 billion sequence reads per sample to the mouse genome (build mm9) and identified 28698 transcripts in 5 samples. Conclusion: Our study represents the first detailed analysis of Hk2/ Pkm2 overexpressed E14 cell transcriptomes, generated by RNA-seq technology We compared transcriptome profiling (RNA-Seq) between normal mouse embryonic stem cell (E14) and E14 cells over-expressing Hexokinase2 (Hk2)/Pyruvate Kinase M2 (Pkm2)
Project description:Mitochondrial metabolism plays a central role in promoting cancer growth and metastatic progression. The transition between a hyperfused and fragmented mitochondrial network is termed mitochondrial dynamics and is important for many mitochondria-associated functions; however, little is known regarding how this process influences metastasis. Here, we show that breast cancer cells with low metastatic potential exhibit a more fused mitochondrial network compared to highly metastatic breast cancer cells. To examine whether a fused mitochondrial network could impair metastasis, we inhibited mitochondrial fission in metastatic breast cancer cells by individual genetic deletion of three key regulators of mitochondrial fission (Drp1, Fis1 and Mff) or pharmacological intervention using leflunomide, an anti-rheumatic drug. These cells displayed a fused mitochondrial network and limited survival under anoikis conditions, consistent with mitochondrial fusion limiting metastasis. Transcriptomics and metabolomics analyses revealed that mitochondrial fusion causes significant alterations in metabolic pathways and processes related to cell adhesion. Functional bioenergetics assays demonstrated that mitochondrial fusion limited the mitochondrial capacity of cancer cells. Mitochondrial fusion in breast cancer cells had no significant effect on primary tumor growth but almost completely ablated lung metastasis in vivo. Furthermore, the transcriptomics signature associated with enhanced mitochondrial fusion correlated with improved survival in patients with breast cancer. Overall, our findings highlight mitochondrial fusion as a therapeutic opportunity for breast cancer.
Project description:Published molecular profiling studies in patients with lymphoma suggested the influence of hypoxia inducible factor-1 alpha (HIF1α) targets in prognosis of DLBCL. Yet, the role of hypoxia in hematological malignancies remains unclear. We observed that activation of HIF1α resulted in global translation repression during hypoxic stress in DLBCL. Protein translation efficiency as measured using 35S-labeled methionine incorporation revealed a ≥50% reduction in translation upon activation of HIF1α. Importantly, translation was not completely inhibited and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with a decrease in mitochondrial function. Screening of primary DLBCL patient samples revealed that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies demonstrated that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide strong support for the direct contribution of HK2 in B-cell lymphoma development and suggest that HK2 is a key metabolic driver of the DLBCL phenotype.ne incorporation revealed a ≥50% reduction in translation upon activation of HIF1α. Importantly, translation was not completely blunted and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with decrease in mitochondrial function. Screening of DLBCL patient samples identified that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies show that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide more definitive proof of direct contribution of HK2 in development of B-cell lymphoma and suggest that HK2 is a key metabolic driver of DLBCL phenotype.
Project description:Lactate was implicated in activation of hepatic stellate cells (HSCs). However, the mechanism by which lactate exerts its effect remains elusive. We show that hexokinase 2 (HK2) is sufficient to change gene expression by histone lactylation but not histone acetylation. Using RNA-seq and CUT&Tag chromatin profiling, we found that induction of HK2 expression in activated HSCs is required for the induced gene expression by elevating histone lactylation. Inhibiting histone lactylation by Hk2 deletion or pharmacological inhibition of lactate production diminishes HSC activation, whereas exogenous lactate but not acetate supplementation rescues the activation phenotype. Thus, lactate produced by activated HSCs determines the HSC fate via histone lactylation. We found that histone acetylation competes with histone lactylation, which could explain why class I HDAC inhibitors impede HSC activation. Finally, HSC-specific or systemic deletion of HK2 inhibits HSC activation and liver fibrosis in vivo. Therefore, we provide evidence that HK2 may be an effective therapeutic target for liver fibrosis.
Project description:Lactate was implicated in activation of hepatic stellate cells (HSCs). However, the mechanism by which lactate exerts its effect remains elusive. We show that hexokinase 2 (HK2) is sufficient to change gene expression by histone lactylation but not histone acetylation. Using RNA-seq and CUT&Tag chromatin profiling, we found that induction of HK2 expression in activated HSCs is required for the induced gene expression by elevating histone lactylation. Inhibiting histone lactylation by Hk2 deletion or pharmacological inhibition of lactate production diminishes HSC activation, whereas exogenous lactate but not acetate supplementation rescues the activation phenotype. Thus, lactate produced by activated HSCs determines the HSC fate via histone lactylation. We found that histone acetylation competes with histone lactylation, which could explain why class I HDAC inhibitors impede HSC activation. Finally, HSC-specific or systemic deletion of HK2 inhibits HSC activation and liver fibrosis in vivo. Therefore, we provide evidence that HK2 may be an effective therapeutic target for liver fibrosis.