PHOSPHO1 Serves as a Key Metabolism-Related Biomarker in the Tumorigenesis of Diffuse Large B-cell Lymphoma.

OBJECTIVE: Diffuse large B-cell lymphoma (DLBCL) is an aggressive type of non-Hodgkin lymphoma. Due to its genetic heterogeneity and abnormal metabolism, many DLBCL patients have a poor prognosis. This study investigated the key metabolism-related genes and potential mechanisms. METHODS: Differentially expressed genes, differentially expressed transcription factors (TFs), and differentially expressed metabolism-related genes (DEMRGs) of glucose and lipid metabolic processes were identified using the edgeR package. Key DEMRGs were screened by Lasso regression, and a prediction model was constructed. The cell type identification by estimating relative subsets of RNA transcripts algorithm was utilized to assess the fraction of immune cells, and Gene Set Enrichment Analysis was used to determine immune-related pathways. A regulatory network was constructed with significant co-expression interactions among TFs, DEMRGs, immune cells/pathways, and hallmark pathways. RESULTS: A total of 1551 DEMRGs were identified. A prognostic model with a high applicability (area under the curve=0.921) was constructed with 13 DEMRGs. Tumorigenesis of DLBCL was highly related to the neutrophil count. Four DEMRGs (PRXL2AB, CCN1, DECR2 and PHOSPHO1) with 32 TF-DEMRG, 36 DEMRG-pathway, 14 DEMRG-immune-cell, 9 DEMRG-immune-gene-set, and 67 DEMRG-protein-chip interactions were used to construct the regulatory network. CONCLUSION: We provided a prognostic prediction model based on 13 DEMRGs for DLBCL. We found that phosphatase, orphan 1 (PHOSPHO1) is positively regulated by regulatory factor X5 (RFX5) and mediates MYC proto-oncogene (MYC) targeting the V2 pathway and neutrophils.

Correction to: microRNA-124 inhibits bone metastasis of breast cancer by repressing Interleukin-11.

An amendment to this paper has been published and can be accessed via the original article.

microRNA-124 inhibits bone metastasis of breast cancer by repressing Interleukin-11.

BACKGROUND: Most patients with breast cancer in advanced stages of the disease suffer from bone metastases which lead to fractures and nerve compression syndromes. microRNA dysregulation is an important event in the metastases of breast cancer to bone. microRNA-124 (miR-124) has been proved to inhibit cancer progression, whereas its effect on bone metastases of breast cancer has not been reported. Therefore, this study aimed to investigate the role and underlying mechanism of miR-124 in bone metastases of breast cancer. METHODS: In situ hybridization (ISH) was used to detect the expression of miR-124 in breast cancer tissues and bone metastatic tissues. Ventricle injection model was constructed to explore the effect of miR-124 on bone metastasis in vivo. The function of cancer cell derived miR-124 in the differentiation of osteoclast progenitor cells was verified in vitro. Dual-luciferase reporter assay was conducted to confirm Interleukin-11 (IL-11) as a miR-124 target. The involvement of miR-124/IL-11 in the prognosis of breast cancer patients with bone metastasis was determined by Kaplan-Meier analysis. RESULTS: Herein, we found that miR-124 was significantly reduced in metastatic bone tissues from breast cancers. Down-regulation of miR-124 was associated with aggressive clinical characteristics and shorter bone metastasis-free survival and overall survival. Restoration of miR-124 suppressed, while inhibition of miR-124 promoted the bone metastasis of breast cancer cells in vivo. At the cellular level, gain of function and loss-of function assays indicated that cancer cell-derived miR-124 inhibited the survival and differentiation of osteoclast progenitor cells. At the molecular level, we demonstrated that IL-11 partially mediated osteoclastogenesis suppression by miR-124 using in vitro and in vivo assays. Furthermore, IL-11 levels were inversely correlated with miR-124, and up-regulation IL-11 in bone metastases was associated with a poor prognosis. CONCLUSIONS: Thus, the identification of a dysregulated miR-124/IL-11 axis helps elucidate mechanisms of breast cancer metastases to bone, uncovers new prognostic markers, and facilitates the development of novel therapeutic targets to treat and even prevent bone metastases of breast cancer.

HIF1/2α mediates hypoxia-induced LDHA expression in human pancreatic cancer cells.

Glycolysis is a typical conduit for energy metabolism in pancreatic cancer (PC) due to the hypoxic microenviroment. Lactate dehydrogenase A (LDHA) catalyzes the conversion of pyruvate to lactate and is considered to be a key checkpoint of anaerobic glycolysis. The aim of the present study was to explore the mechanism of interactions between hypoxia, HIF-1/2α and LDHA, and the function of LDHA on PC cells by analyzing 244 PC and paratumor specimens. It was found that LDHA was over-expressed and related to tumor stages. The result of in vitro study demonstrated that hypoxia induced LDHA expression. To explore the relationship between HIF and LDHA, chromatin immunoprecipitation assay and luciferase assay were performed. The result showed that HIF-1/2α bound to LDHA at 89bp under the hypoxic condition. Furthermore, knockdown of endogenous HIF-1α and HIF-2α decreased the LDHA expression even in the hypoxic condition, which was accompanied with a significant decrease in lactate production and glucose utilization (p < 0.01). Immunofluorescence in the 244 specimens showed that HIF-1/2α was over-expressed and associated with LDHA over-expression (p < 0.0001). Forced expression of LDHA promoted the growth and migration of PC cells, while knocking down the expression of LDHA inhibited the cell growth and migration markedly. In summary, the present study proved that HIF1/2α could activate LDHA expression in human PC cells, and high expression of LDHA promoted the growth and migration of PC cells.

HIF-1α activates hypoxia-induced BCL-9 expression in human colorectal cancer cells.

B-cell CLL/lymphoma 9 protein (BCL-9), a multi-functional co-factor in Wnt signaling, induced carcinogenesis as well as promoting tumor progression, metastasis and chemo-resistance in colorectal cancer (CRC). However, the mechanisms for increased BCL-9 expression in CRC were not well understood. Here, we report that hypoxia, a hallmark of solid tumors, induced BCL-9 mRNA expression in human CRC cells. Analysis of BCL-9 promoter revealed two functional hypoxia-responsive elements (HRE-B and HRE-C) that can be specifically bound with and be transactivated by hypoxia inducible factors (HIF) -1α but not HIF-2α. Consistently, ectopic expression of HIF-1α but not HIF-2α transcriptionally induced BCL-9 expression levels in cells. Knockdown of endogenous HIF-1α but not HIF-2α by siRNA largely abolished the induction of HIF by hypoxia. Furthermore, there was a strong association of HIF-1α expression with BCL-9 expression in human CRC specimens. In summary, results from this study demonstrated that hypoxia induced BCL-9 expression in human CRC cells mainly through HIF-1α, which could be an important underlying mechanism for increased BCL-9 expression in CRC.

Generation and characterization of Tmeff2 mutant mice.

TMEFF2 is a single-transmembrane protein containing one EGF-like and two follistatin-like domains. Some studies implicated TMEFF2 as a tumor suppressor for prostate and other cancers, whereas others reported TMEFF2 functioning as a growth factor for neurons and other cells. To gain insights into the apparently conflicting roles of TMEFF2, we generated a null allele of Tmeff2 gene by replacing its first coding exon with human placental alkaline phosphatase cDNA (Tmeff2(PLAP)). Tmeff2(PLAP/PLAP) homozygous mutant mice are born normal, but show growth retardation and die around weaning age. Tmeff2 is widely expressed in the nervous system, and the Tmeff2(PLAP) knock-in allele enables the visualization of neuronal innervations of skin and internal organs with a simple alkaline phosphatase staining. Tmeff2 is also highly expressed in prostate gland and white adipose tissues (WAT). However, with the exception of reduced WAT mass, extensive anatomical and molecular analyses failed to detect any structural or molecular abnormalities in the brain, the spinal cord, the enteric nervous system, or the prostate in the Tmeff2 mutants. No tumors were found in Tmeff2-mutant mice. The Tmeff2(PLAP/PLAP) knock-in mouse is an useful tool for studying the in vivo biological functions of TMEFF2.