Loss of ß-Arrestins or six Gα proteins in HEK293 cells caused Warburg effect and prevented progesterone-induced rapid proteasomal degradation of progesterone receptor membrane component 1.

Hormonal dysregulation plays a significant role in the metabolic switching during malignant transformation. Progesterone Receptor Membrane Component 1 (PGRMC1) is a single-pass transmembrane receptor activated by the binding of progesterone (P4), a sex hormone. In a previous study, P4 treatment caused rapid (within 30 min) induction of aerobic glycolysis in transformed HEK293 cells, a hallmark malignant phenotype known as the Warburg effect. This metabolic reprogramming was associated with the proteasomal degradation of a 70 kilodalton (kDa) PGRMC1. PGRMC1 interacts with a variety of proteins, including G protein-coupled receptors (GPCRs) and P4-PGRMC1 signaling modulates cyclic adenosine monophosphate (cAMP) production. Therefore, we hypothesized that the P4-induced Warburg effect and proteasomal degradation of PGRMC1 involve G proteins and ß-Arrestins (ARRBs). In the present study, we investigated P4-induced aerobic glycolysis, proteasomal degradation of p70 PGRMC1, as well as abundance and subcellular translocation of PGRMC1 along with two key glycolytic enzymes Hexokinase 1 (HK1) and Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) in six Gα subunit (Gsix) proteins or ARRB1/2-deficient HEK293 cells. Loss of ARRB1/2 or Gsix proteins inhibited P4-induced p70 PGRMC1 degradation but failed to prevent the P4-induced Warburg effect. Also, deficiency of ARRB1/2 or Gsix proteins differentially affected the basal as well as P4-induced abundance and subcellular translocation of PGRMC1, HK1, and GAPDH proteins. Overall, the findings indicate that P4-PGRMC1-mediated metabolic reprogramming in HEK293 cells depends on ß-Arrestins and Gα proteins suggesting the involvement of an underlying GPCR signal transduction pathway.

Overexpression of long non-coding RNA urothelial carcinoma associated 1 causes paclitaxel (Taxol) resistance in colorectal cancer cells by promoting glycolysis.

Some colorectal cancer patients show resistance to conventional chemotherapeutic agents including Taxol. This study investigated the roles of lncRNA urothelial carcinoma-associated 1 (UCA1) in the modulation of Taxol resistance in human colorectal cancer cells. According to our results, UCA1 was significantly upregulated in colon cancer cell lines/tissues. Construction of the UCA1 overexpression vector revealed that high UCA1 expression was responsible for Taxol resistance and that Taxol can induce UCA1 expression. Importantly, Taxol-resistant cells had a higher glycolysis rate and upregulated expression of the key glycolysis enzymes hexokinase 2 (HK2) and lactate dehydrogenase A (LDHA) than Taxol-sensitive cells. Further research demonstrated that UCA1 could directly regulate glycolysis by regulating HK2 and LDHA expression, which contributes to Taxol resistance. UCA1 is a potential target to overcome chemoresistance in colorectal cancer. We report the modulation of UCA-1-regulated glycolysis as a novel anticancer strategy along with the novel role of UCA1 in Taxol resistance.

HIF-1α Modulates Core Metabolism and Virus Replication in Primary Airway Epithelial Cells Infected with Respiratory Syncytial Virus.

Metabolic reprogramming of host cells is key to the foundation of a successful viral infection. Hypoxia inducible factors (HIFs) mediate oxygen utilization by regulating cellular metabolism and redox homeostasis. Under normoxic conditions, HIF proteins are synthesized and subsequently degraded following ubiquitination to allow for normal metabolic activities. Recent studies suggest that respiratory syncytial virus (RSV) has the ability to induce HIF-1α stabilization and accumulation through non-hypoxic mechanisms. This makes the HIF pathway a potential avenue of approach for RSV therapeutic development. Using a model of primary human small alveolar epithelial cells, we demonstrate RSV infections to greatly alter cellular metabolism in favor of the glycolytic and pentose phosphate pathways. Additionally, we show RSV infections to stabilize HIF-1α and HIF-2α expression in these cells. Inhibition of HIF-1α, but not HIF-2α, was found to significantly reduce RSV replication as well as the glycolytic pathway, as measured by the expression of hexokinase II. Our study contributes to the understanding of RSV-mediated changes to cellular metabolism and supports further investigation into anti-HIF-1α therapeutics for RSV infections.

Momordica charantia Suppresses Inflammation and Glycolysis in Lipopolysaccharide-Activated RAW264.7 Macrophages.

Macrophage activation is a key event that triggers inflammatory response. The activation is accompanied by metabolic shift such as upregulated glucose metabolism. There are accumulating evidences showing the anti-inflammatory activity of Momordica charantia. However, the effects of M. charantia on inflammatory response and glucose metabolism in activated macrophages have not been fully established. The present study aimed to examine the effect of M. charantia in modulating lipopolysaccharide (LPS)-induced inflammation and perturbed glucose metabolism in RAW264.7 murine macrophages. The results showed that LPS-induced NF-κB (p65) nuclear translocation was inhibited by M. charantia treatment. In addition, M. charantia was found to reduce the expression of inflammatory genes including IL6, TNF-α, IL1ß, COX2, iNOS, and IL10 in LPS-treated macrophages. Furthermore, the data showed that M. charantia reduced the expression of GLUT1 and HK2 genes and lactate production (-28%), resulting in suppression of glycolysis. Notably, its effect on GLUT1 gene expression was found to be independent of LPS-induced inflammation. A further experiment also indicated that the bioactivities of M. charantia may be attributed to its key bioactive compound, charantin. Taken together, the study provided supporting evidences showing the potential of M. charantia for the treatment of inflammatory disorders.

Cyclin-Dependent Kinases 8 and 19 Regulate Host Cell Metabolism during Dengue Virus Serotype 2 Infection.

Dengue virus infection is associated with the upregulation of metabolic pathways within infected cells. This effect is common to infection by a broad array of viruses. These metabolic changes, including increased glucose metabolism, oxidative phosphorylation and autophagy, support the demands of viral genome replication and infectious particle formation. The mechanisms by which these changes occur are known to be, in part, directed by viral nonstructural proteins that contact and control cellular structures and metabolic enzymes. We investigated the roles of host proteins with overarching control of metabolic processes, the transcriptional regulators, cyclin-dependent kinase 8 (CDK8) and its paralog, CDK19, as mediators of virally induced metabolic changes. Here, we show that expression of CDK8, but not CDK19, is increased during dengue virus infection in Huh7 human hepatocellular carcinoma cells, although both are required for efficient viral replication. Chemical inhibition of CDK8 and CDK19 with Senexin A during infection blocks virus-induced expression of select metabolic and autophagic genes, hexokinase 2 (HK2) and microtubule-associated protein 1 light chain 3 (LC3), and reduces viral genome replication and infectious particle production. The results further define the dependence of virus replication on increased metabolic capacity in target cells and identify CDK8 and CDK19 as master regulators of key metabolic genes. The common inhibition of CDK8 and CDK19 offers a host-directed therapeutic intervention that is unlikely to be overcome by viral evolution.

Glycolytic enzyme hexokinase II is a putative therapeutic target in B-cell malignant lymphoma.

Hexokinase II (HXKII) is a key regulator of glucose metabolism that converts glucose to glucose 6-phosphate. Furthermore, HXKII blocks mitochondria-dependent apoptosis by inhibiting the release of cytochrome c. HXKII overexpression is frequently observed in several types of cancer and confers chemoresistance to cancer cells. In the present study, we found that compared with cell lines generated from diffuse large-B-cell lymphoma (DLBCL) patients, cell lines with features of Burkitt lymphoma have higher levels of HXKII because of the activation of both c-MYC and HIF-1. Under normoxia, HXKII levels were correlated with the growth ability of each B-cell lymphoma cell line. HXKII levels were further enhanced when the B-cell lymphoma cells were cultured under hypoxia. The high levels of HXKII induced by hypoxia conferred cisplatin resistance in all tested B-cell lymphoma cell lines. The HDAC inhibitor panobinostat significantly suppressed HXKII expression under both normoxic and hypoxic conditions. Importantly, panobinostat reversed the anti-lymphoma action of cisplatin, and this effect was diminished by hypoxia. These data suggest that HXKII plays different roles, including in the regulation of glycolysis and inhibition of apoptosis, depending on its expression levels. Furthermore, inhibition of HXKII expression by panobinostat may represent a new and attractive strategy to overcome cisplatin resistance.

Heterologous overexpression of active hexokinases from microsporidia Nosema bombycis and Nosema ceranae confirms their ability to phosphorylate host glucose.

The secretion of hexokinases (HKs) by microsporidia followed by their accumulation in insect host nuclei suggests that these enzymes play regulatory and catalytic roles in infected cells. To confirm whether HKs exert catalytic functions in insect cells, we expressed in E. coli the functionally active HKs of two entomopathogenic microsporidia, Nosema bombycis and Nosema ceranae, that cause silkworm and honey bee nosematoses. N. bombycis HK with C-terminal polyHis tag and N. ceranae enzyme with N-terminal polyHis tag were cloned into pOPE101 and pRSET vectors, respectively, and overexpressed. Specific activities of N. bombycis and N. ceranae enzymes isolated by metal chelate affinity chromatography were 29.2 ± 0.5 and 60.2 ± 1.2 U/mg protein at an optimal pH range of 8.5-9.5. The kinetic characteristics of the recombinant enzymes were similar to those of HKs from other parasitic and free-living organisms. N. bombycis HK demonstrated Km 0.07 ± 0.01 mM and kcat 1726 min-1 for glucose, and Km 0.39 ± 0.05 mM and kcat 1976 min-1 for ATP, at pH 8.8. N. ceranae HK showed Km 0.3 ± 0.04 mM and kcat 3293 min-1 for glucose, and Km 1.15 ± 0.11 mM and kcat 3732 min-1 for ATP, at the same pH value. These data demonstrate the capability of microsporidia-secreted HKs to phosphorylate glucose in infected cells, suggesting that they actively mediate the effects of the parasite on host metabolism. The present findings justify further study of the enzymes as targets to suppress the intracellular development of silkworm and honey bee pathogens.

OsAGO2 controls ROS production and the initiation of tapetal PCD by epigenetically regulating OsHXK1 expression in rice anthers.

Proteins of the ARGONAUTE (AGO) family function in the epigenetic regulation of gene expression. Although the rice (Oryza sativa) genome encodes 19 predicted AGO proteins, few of their functions have thus far been characterized. Here, we show that the AGO protein OsAGO2 regulates anther development in rice. OsAGO2 was highly expressed in anthers. Knockdown of OsAGO2 led to the overaccumulation of reactive oxygen species (ROS) and abnormal anther development, causing premature initiation of tapetal programmed cell death (PCD) and pollen abortion. The expression level of Hexokinase 1 (OsHXK1) increased significantly, and the methylation levels of its promoter decreased, in plants with knocked-down OsAGO2 expression. Overexpression of OsHXK1 also resulted in the overaccumulation of ROS, premature initiation of PCD, and pollen abortion. Moreover, knockdown of OsHXK1 restored pollen fertility in OsAGO2 knockdown plants. Chromatin immunoprecipitation assays demonstrated that OsAGO2 binds directly to the OsHXK1 promoter region, suggesting that OsHXK1 is a target gene of OsAGO2. These results indicate that OsHXK1 controls the appropriate production of ROS and the proper timing of tapetal PCD and is directly regulated by OsAGO2 through epigenetic regulation.

miR-603 targeted hexokinase-2 to inhibit the malignancy of ovarian cancer cells.

The Warburg effect, characterized by energy production through a high rate of aerobic glycolysis, is a metabolic hallmark of cancer cells. We previously found that ginsenoside 20(S)-Rg3 upregulated miR-603 and impaired the malignancy of ovarian cancer cells by inhibiting the Warburg effect. However, the precise functional role of miR-603 in ovarian cancer progression remains poorly defined. Here, we report that the level of miR-603 in ovarian cancer tissues is significantly lower than that in para-tumor tissues. Overexpression of miR-603 in ovarian cancer cells inhibits the Warburg effect as evidenced by a decrease in glucose consumption, lactate production and hexokinase-2 (HK2) expression, reduces cell proliferation in vitro, and weakens their migration and invasion. Further, miR-603 directly targets HK2 as indicated in a luciferase reporter assay. In contrast to agomiR-NC, agomiR-603 treatment significantly inhibits tumor growth in vivo and the Warburg effect, which is illustrated by a decreased uptake of 18F-FDG in subcutaneous xenografts and HK2 downregulation. Finally, miR-603 is negatively regulated by DNMT3A-mediated DNA methylation in the promoter region of its precursor gene, suggesting that 20(S)-Rg3 antagonizes DNMT3A-mediated DNA methylation to impair growth, migration and invasion of ovarian cancer cells. In conclusion, miR-603 is a tumor suppressor targeting HK2 in ovarian cancer and its low level may result from DNMT3A-mediated methylation.

TGF-ß1 upregulates the expression of lncRNA UCA1 and its downstream HXK2 to promote the growth of hepatocellular carcinoma.

OBJECTIVE: TGF-ß1 plays pivotal roles in the development of various malignancies such as hepatocellular carcinoma, while the mechanism of the TGF-ß1 function in hepatocellular carcinoma remains unclear. Our study aimed to investigate the molecular mechanisms of the TGF-ß1 function in hepatocellular carcinoma. PATIENTS AND METHODS: Tumor tissues and adjacent healthy tissues were collected from hepatocellular carcinoma. Blood samples were collected from both hepatocellular carcinoma patients and healthy controls. Expression of TGF-ß1, long non-coding RNA (lncRNA) UCA1 and hexokinase 2 (HXK2) in those tissues was detected by qRT-PCR. All patients were followed up for 5 years, and prognostic values of serum HOTAIR for hepatocellular carcinoma were investigated by survival curve analysis. TGF-ß1, UCA1, and HXK2 overexpression hepatocellular carcinoma cell lines were established, and the effects on cell proliferation were detected by the CCK-8 assay. Interactions between TGF-ß1, UCA1, and HXK2 were explored by Western blot. Effects of TGF-ß1 on lactate production, glucose uptake, and ATP production were detected by lactate assay, glucose uptake assay, and ATP assay. RESULTS: TGF-ß1, UCA1, and HXK2 expression levels were upregulated in tumor tissues comparing with adjacent healthy tissues. Serum levels of TGF-ß1, UCA1, and HXK2 increased with the increases of primary tumor stage. Patients that have high serum levels of TGF-ß1, UCA1, and HXK2 showed lower overall survival rate compared with patients with low serum levels of TGF-ß1, UCA1, and HXK2. TGF-ß1, UCA1, and HXK2 overexpression promoted proliferation of hepatocellular carcinoma cell. TGF-ß1 is a positive upstream regulator of UCA1, which is a positive upstream regulator of HXK2. TGF-ß1 overexpression increased lactate production, glucose uptake and ATP production in hepatocellular carcinoma. CONCLUSIONS: TGF-ß1 may accelerate cancer cell energy metabolism to promote the growth of hepatocellular carcinoma by upregulating UCA1 and its downstream HXK2.

Deficiency of tumor suppressor Merlin facilitates metabolic adaptation by co-operative engagement of SMAD-Hippo signaling in breast cancer.

The NF2 gene encodes the tumor and metastasis suppressor protein Merlin. Merlin exerts its tumor suppressive role by inhibiting proliferation and inducing contact-growth inhibition and apoptosis. In the current investigation, we determined that loss of Merlin in breast cancer tissues is concordant with the loss of the inhibitory SMAD, SMAD7, of the TGF-ß pathway. This was reflected as dysregulated activation of TGF-ß signaling that co-operatively engaged with effectors of the Hippo pathway (YAP/TAZ/TEAD). As a consequence, the loss of Merlin in breast cancer resulted in a significant metabolic and bioenergetic adaptation of cells characterized by increased aerobic glycolysis and decreased oxygen consumption. Mechanistically, we determined that the co-operative activity of the Hippo and TGF-ß transcription effectors caused upregulation of the long non-coding RNA Urothelial Cancer-Associated 1 (UCA1) that disengaged Merlin's check on STAT3 activity. The consequent upregulation of Hexokinase 2 (HK2) enabled a metabolic shift towards aerobic glycolysis. In fact, Merlin deficiency engendered cellular dependence on this metabolic adaptation, endorsing a critical role for Merlin in regulating cellular metabolism. This is the first report of Merlin functioning as a molecular restraint on cellular metabolism. Thus, breast cancer patients whose tumors demonstrate concordant loss of Merlin and SMAD7 may benefit from an approach of incorporating STAT3 inhibitors.

[Overexpression of microRNAs miR-9, -98, and -199 Correlates with the Downregulation of HK2 Expression in Colorectal Cancer].

Glycolysis activation is one of the main features of energy metabolism in cancer cells that is associated with the increase in glycolytic enzyme synthesis, primarily, hexokinases (HKs), in many types of tumors. Conversely, in colorectal cancer (CRC) the decrease in the expression of HK2 gene, which encodes one of the key rate-limiting enzyme of glycolysis, was revealed, thus, the study of the mechanisms of its inhibition in CRC is of particular interest. To search for potential microRNAs, inhibiting the expression of HK2 in CRC, we have performed the analysis of data from "The Cancer Genome Atlas" (TCGA) and five microRNA-mRNA target interaction databases (TargetScan, DIANA microT, mirSVR (miRanda), PicTar, and miRTarBase) using original CrossHub software. Seven microRNAs containing binding site on mRNA HK2, which expression is negatively correlated with HK2 expression, were selected for further analysis. The expression levels of these microRNAs and mRNA HK2 were estimated by quantitative PCR on a set of CRC samples. It has been shown, that the expression of three microRNAs (miR-9-5p, -98-5p, and -199-5p) was increased and correlated negatively with mRNA level of HK2 gene. Thus, downregulation of HK2 gene may be caused by its negative regulation through microRNAs miR-9-5p, -98-5p, and -199-5p.

Jolkinolide B inhibits glycolysis by downregulating hexokinase 2 expression through inactivating the Akt/mTOR pathway in non-small cell lung cancer cells.

Jolkinolide B (JB), a bioactive compound isolated from herbal medicine, has been found to inhibit tumor growth by altering glycolysis. However, whether glycolysis is influenced by JB in non-small cell lung cancer (NSCLC) cells and the mechanism remain unknown. The aim of the present study was to evaluate the effect of JB on the glycolysis in NSCLC cells and the underlying molecular mechanism. The results showed that JB treatment inhibited cell viability of A549 and H1299 cells in a concentration-dependent manner. JB reduced the glucose consumption, lactate production, and HK2 expression. The expressions of p-Akt and p-mTOR were also decreased by JB treatment. Knockdown of HK2 reduced glucose consumption and lactate production. Inhibition of the Akt/mTOR pathway decreased HK2 expression and inhibited glycolysis. In conclusion, the results indicated that JB inhibits glycolysis by down-regulating HK2 expression through inactivating the Akt/mTOR pathway in NSCLC cells, suggesting that JB might be a potential therapeutic agent for the treatment of NSCLC.

Hexokinase 2-dependent hyperglycolysis driving microglial activation contributes to ischemic brain injury.

Hyperglycolysis, observed within the penumbra zone during brain ischemia, was shown to be detrimental for tissue survival because of lactate accumulation and reactive oxygen species overproduction in clinical and experimental settings. Recently, mounting evidence suggests that glycolytic reprogramming and induced metabolic enzymes can fuel the activation of peripheral immune cells. However, the possible roles and details regarding hyperglycolysis in neuroinflammation during ischemia are relatively poorly understood. Here, we investigated whether overactivated glycolysis could activate microglia and identified the crucial regulators of neuroinflammatory responses in vitro and in vivo. Using BV 2 and primary microglial cultures, we found hyperglycolysis and induction of the key glycolytic enzyme hexokinase 2 (HK2) were essential for microglia-mediated neuroinflammation under hypoxia. Mechanistically, HK2 up-regulation led to accumulated acetyl-coenzyme A, which accounted for the subsequent histone acetylation and transcriptional activation of interleukin (IL)-1ß. The inhibition and selective knockdown of HK2 in vivo significantly protected against ischemic brain injury by suppressing microglial activation and IL-1ß production in male Sprague-Dawley rats subjected to transient middle cerebral artery occlusion (MCAo) surgery. We provide novel insights for HK2 specifically serving as a neuroinflammatory determinant, thus explaining the neurotoxic effect of hyperglycolysis and indicating the possibility of selectively targeting HK2 as a therapeutic strategy in acute ischemic stroke.

Spatio-temporal expression of Hexokinase-3 in the injured female rat spinal cords.

Hexokinase-3 (HK3) is a member of hexokinase family, which can catalyze the first step of glucose metabolism. It can increase ATP levels, reduce the production of reactive oxygen species, increase mitochondrial biogenesis, protect mitochondrial membrane potential and play an antioxidant role. However, the change of its expression in spinal cord after injury is still unknown. In this study, we investigated the spatio-temporal expression of HK3 in the spinal cords by using a spinal cord injury (SCI) model in adult female Sprague-Dawley rats. Quantitative reverse transcription-PCR and western blot analysis revealed that HK3 could be detected in sham-opened spinal cords. After SCI, it gradually increased, reached a peak at 7 days post-injury (dpi), and then gradually decreased with the prolonging of injury time, but still maintained at a higher level for up to 28 dpi (the longest time evaluated in this study). Immunofluorescence staining showed that HK3 was found in GFAP+, ß-tubulin III+ and IBA-1+ cells in sham-opened spinal cords. After SCI, in addition to the above-mentioned cells, it could also be found in CD45+ and CD68+ cells. These results demonstrate that HK3 is mainly expressed in astrocytes, neurons and microglia in normal spinal cords, and could rapidly increase in infiltrated leukocytes, activated microglia/macrophages and astrocytes after SCI. These data suggest that HK3 may be involved in the pathologic process of SCI by promoting glucose metabolism.

Inhibition of miR-143 during ischemia cerebral injury protects neurones through recovery of the hexokinase 2-mediated glucose uptake.

Ischemic stroke, a major cause of death, is caused by occlusion of a blood vessel, resulting in significant reduction in regional cerebral blood flow. MiRNAs are a family of short noncoding RNAs (18-22 nts) and bind the 3'-UTR of their target genes to suppress the gene expression post-transcriptionally. In the present study, we report that miR-143 is down-regulated in rat neurones but highly expressed in astrocytes. In vivo middle cerebral artery occlusion (MCAO) and ex vivo oxygen-glucose deprivation (OGD) results showed that miR-143 was significantly induced by ischemia injury. Meanwhile, we observed suppression of glucose uptake and lactate product of rat brain and primary neurones after MCAO or OGD. The glycolysis enzymes hexokinase 2 (HK2), PKM2, and LDHA were inhibited by MCAO or OGD at protein and mRNA levels. In addition, overexpression of miR-143 significantly inhibited HK2 expression, glucose uptake, and lactate product. We report that HK2 is a direct target of miR-143. Importantly, restoration of HK2 in miR-143 overexpressing rat neurones recovered glucose uptake and lactate product. Our results demonstrated inhibition of miR-143 during OGD could protect rat neuronal cells from ischemic brain injury (IBI). In summary, the present study reveals a miRNA-mediated neuron protection during IBI, providing a new strategy for the development of therapeutic agents against IBI.

Adipocyte Metabolic Pathways Regulated by Diet Control the Female Germline Stem Cell Lineage in Drosophila melanogaster.

Nutrients affect adult stem cells through complex mechanisms involving multiple organs. Adipocytes are highly sensitive to diet and have key metabolic roles, and obesity increases the risk for many cancers. How diet-regulated adipocyte metabolic pathways influence normal stem cell lineages, however, remains unclear. Drosophila melanogaster has highly conserved adipocyte metabolism and a well-characterized female germline stem cell (GSC) lineage response to diet. Here, we conducted an isobaric tags for relative and absolute quantification (iTRAQ) proteomic analysis to identify diet-regulated adipocyte metabolic pathways that control the female GSC lineage. On a rich (relative to poor) diet, adipocyte Hexokinase-C and metabolic enzymes involved in pyruvate/acetyl-CoA production are upregulated, promoting a shift of glucose metabolism toward macromolecule biosynthesis. Adipocyte-specific knockdown shows that these enzymes support early GSC progeny survival. Further, enzymes catalyzing fatty acid oxidation and phosphatidylethanolamine synthesis in adipocytes promote GSC maintenance, whereas lipid and iron transport from adipocytes controls vitellogenesis and GSC number, respectively. These results show a functional relationship between specific metabolic pathways in adipocytes and distinct processes in the GSC lineage, suggesting the adipocyte metabolism-stem cell link as an important area of investigation in other stem cell systems.

Low expression of hexokinase-2 is associated with false-negative FDG-positron emission tomography in multiple myeloma.

18F-Fluorodeoxyglucose (FDG)-positron emission tomography (PET) and diffusion-weighted magnetic resonance imaging with background signal suppression (DWIBS) are 2 powerful functional imaging modalities in the evaluation of malignant plasma cell (PC) disease multiple myeloma (MM). Preliminary observations have suggested that MM patients with extensive disease according to DWIBS may be reported as being disease-free on FDG-PET ("PET false-negative"). The aim of this study was to describe the proportion of PET false-negativity in a representative set of 227 newly diagnosed MM patients with simultaneous assessment of FDG-PET and DWIBS, and to identify tumor-intrinsic features associated with this pattern. We found the incidence of PET false-negativity to be 11%. Neither tumor load-associated parameters, such as degree of bone marrow PC infiltration, nor the PC proliferation rate were associated with this subset. However, the gene coding for hexokinase-2, which catalyzes the first step of glycolysis, was significantly lower expressed in PET false-negative cases (5.3-fold change, P < .001) which provides a mechanistic explanation for this feature. In conclusion, we demonstrate a relevant number of patients with FDG-PET false-negative MM and a strong association between hexokinase-2 expression and this negativity: a finding which may also be relevant for clinical imaging of other hematological cancers.

Glycolysis-related protein expression in thyroid cancer.

We aimed to demonstrate the differences in the expression of glucose metabolism-related proteins according to the thyroid cancer subtypes and investigate the implications of these differences. A total of 566 thyroid cancer patients, including 342 cases of papillary thyroid carcinoma, 112 cases of follicular carcinoma, 70 cases of medullary carcinoma, 23 cases of poorly differentiated carcinoma, 19 cases of anaplastic carcinoma, and 152 cases of follicular adenoma, were enrolled in the study. Immunohistochemical staining for glucose transporter 1, hexokinase II, carbonic anhydrase IX, and monocarbonylate transporter 4 was performed, and the relationship between immunoreactivity and clinicopathologic parameters was analyzed. Glucose transporter 1 and tumoral monocarbonylate transporter 4 expression levels were shown to be the highest in anaplastic carcinoma, and medullary carcinoma showed the highest carbonic anhydrase IX and lowest hexokinase II levels compared with other subtypes. Stromal expression of monocarbonylate transporter 4 was observed in papillary thyroid carcinoma and anaplastic carcinoma samples. Conventional papillary thyroid carcinoma tumors expressed higher levels of glucose transporter 1, and tumoral and stromal monocarbonylate transporter 4, than the follicular variant, which showed a higher expression of carbonic anhydrase IX. Papillary thyroid carcinoma samples with BRAF V600E mutation were shown to have higher glucose transporter 1, hexokinase II, carbonic anhydrase IX, and tumoral monocarbonylate transporter 4 expression levels. Univariate analysis showed that papillary thyroid carcinoma cases with glucose transporter 1 positivity had shorter overall survival, patients with medullary carcinoma and hexokinase II positivity were shown to have a shorter disease-free survival and overall survival, and tumoral monocarbonylate transporter 4 positivity was associated with shorter overall survival compared with papillary thyroid carcinoma patients with negativity for each marker. Disease-free survival and overall survival of patients with poorly differentiated carcinoma were shown to be significantly decreased when glucose transporter 1 and tumoral monocarbonylate transporter 4 are expressed. We demonstrated that the expression levels of glycolysis-related proteins differ between thyroid cancer subtypes and are correlated with poorer prognosis, depending on the subtype.

Mff-Dependent Mitochondrial Fission Contributes to the Pathogenesis of Cardiac Microvasculature Ischemia/Reperfusion Injury via Induction of mROS-Mediated Cardiolipin Oxidation and HK2/VDAC1 Disassociation-Involved mPTP Opening.

BACKGROUND: The cardiac microvascular system ischemia/reperfusion injury following percutaneous coronary intervention is a clinical thorny problem. This study explores the mechanisms by which ischemia/reperfusion injury induces cardiac microcirculation collapse. METHODS AND RESULTS: In wild-type mice, mitochondrial fission factor (Mff) expression increased in response to acute microvascular ischemia/reperfusion injury. Compared with wild-type mice, homozygous Mff-deficient (Mffgt) mice exhibited a smaller infarcted area, restored cardiac function, improved blood flow, and reduced microcirculation perfusion defects. Histopathology analysis demonstrated that cardiac microcirculation endothelial cells (CMECs) in Mffgt mice had an intact endothelial barrier, recovered phospho-endothelial nitric oxide synthase production, opened lumen, undivided mitochondrial structures, and less CMEC death. In vitro, Mff-deficient CMECs (derived from Mffgt mice or Mff small interfering RNA-treated) demonstrated less mitochondrial fission and mitochondrial-dependent apoptosis compared with cells derived from wild-type mice. The loss of Mff inhibited mitochondrial permeability transition pore opening via blocking the oligomerization of voltage-dependent anion channel 1 and subsequent hexokinase 2 separation from mitochondria. Moreover, Mff deficiency reduced the cyt-c leakage into the cytoplasm by alleviating cardiolipin oxidation resulting from damage to the electron transport chain complexes and mitochondrial reactive oxygen species overproduction. CONCLUSIONS: This evidence clearly illustrates that microcirculatory ischemia/reperfusion injury can be attributed to Mff-dependent mitochondrial fission via voltage-dependent anion channel 1/hexokinase 2-mediated mitochondrial permeability transition pore opening and mitochondrial reactive oxygen species/cardiolipin involved cyt-c release.