Pyruvate Dehydrogenase Kinase Inhibition by Dichloroacetate in Melanoma Cells Unveils Metabolic Vulnerabilities.

Melanoma is characterized by high glucose uptake, partially mediated through elevated pyruvate dehydrogenase kinase (PDK), making PDK a potential treatment target in melanoma. We aimed to reduce glucose uptake in melanoma cell lines through PDK inhibitors dichloroacetate (DCA) and AZD7545 and through PDK knockdown, to inhibit cell growth and potentially unveil metabolic co-vulnerabilities resulting from PDK inhibition. MeWo cells were most sensitive to DCA, while SK-MEL-2 was the least sensitive, with IC50 values ranging from 13.3 to 27.0 mM. DCA strongly reduced PDH phosphorylation and increased the oxygen consumption rate:extracellular acidification rate (OCR:ECAR) ratio up to 6-fold. Knockdown of single PDK isoforms had similar effects on PDH phosphorylation and OCR:ECAR ratio as DCA but did not influence sensitivity to DCA. Growth inhibition by DCA was synergistic with the glutaminase inhibitor CB-839 (2- to 5-fold sensitization) and with diclofenac, known to inhibit monocarboxylate transporters (MCTs) (3- to 8-fold sensitization). CB-839 did not affect the OCR:ECAR response to DCA, whereas diclofenac strongly inhibited ECAR and further increased the OCR:ECAR ratio. We conclude that in melanoma cell lines, DCA reduces proliferation through reprogramming of cellular metabolism and synergizes with other metabolically targeted drugs.

Breast Implant-associated Anaplastic Large Cell Lymphoma: An Evidence-based Systematic Review.

OBJECTIVE: This evidence-based systematic review synthesizes and critically appraises current clinical recommendations and advances in the diagnosis and treatment of BIA-ALCL. This review also aims to broaden physician awareness across diverse specialties, particularly among general practitioners, breast surgeons, surgical oncologists, and other clinicians who may encounter patients with breast implants in their practice. BACKGROUND: BIA-ALCL is an emerging and treatable immune cell cancer definitively linked to textured-surface breast implants. Although the National Comprehensive Cancer Network (NCCN) consensus guidelines and other clinical recommendations have been established, the evidence supporting these guidelines has not been systematically studied. The purpose of this evidence-based systematic review is to synthesize and critically appraise current clinical guidelines and recommendations while highlighting advances in diagnosis and treatment and raising awareness for this emerging disease. METHODS: This evidence-based systematic review evaluated primary research studies focusing on the diagnosis and treatment of BIA-ALCL that were published in PubMed, Google Scholar, and other scientific databases through March 2020. RESULTS AND CONCLUSIONS: The clinical knowledge of BIA-ALCL has evolved rapidly over the last several years with major advances in diagnosis and treatment, including en bloc resection as the standard of care. Despite a limited number of high-quality clinical studies comprised mainly of Level III and Level V evidence, current evidence aligns with established NCCN consensus guidelines. When diagnosed and treated in accordance with NCCN guidelines, BIA-ALCL carries an excellent prognosis.

Simultaneous Quantification of the Concentration and Carbon Isotopologue Distribution of Polar Metabolites in a Single Analysis by Gas Chromatography and Mass Spectrometry.

13C-isotope tracing is a frequently employed approach to study metabolic pathway activity. When combined with the subsequent quantification of absolute metabolite concentrations, this enables detailed characterization of the metabolome in biological specimens and facilitates computational time-resolved flux quantification. Classically, a 13C-isotopically labeled sample is required to quantify 13C-isotope enrichments and a second unlabeled sample for the quantification of metabolite concentrations. The rationale for a second unlabeled sample is that the current methods for metabolite quantification rely mostly on isotope dilution mass spectrometry (IDMS) and thus isotopically labeled internal standards are added to the unlabeled sample. This excludes the absolute quantification of metabolite concentrations in 13C-isotopically labeled samples. To address this issue, we have developed and validated a new strategy using an unlabeled internal standard to simultaneously quantify metabolite concentrations and 13C-isotope enrichments in a single 13C-labeled sample based on gas chromatography-mass spectrometry (GC/MS). The method was optimized for amino acids and citric acid cycle intermediates and was shown to have high analytical precision and accuracy. Metabolite concentrations could be quantified in small tissue samples (≥20 mg). Also, we applied the method on 13C-isotopically labeled mammalian cells treated with and without a metabolic inhibitor. We proved that we can quantify absolute metabolite concentrations and 13C-isotope enrichments in a single 13C-isotopically labeled sample.

Intraintestinal fermentation of fructo- and galacto-oligosaccharides and the fate of short-chain fatty acids in humans.

Consumption of fructo- (FOS) and galacto-oligosaccharides (GOS) has health benefits which have been linked in part to short-chain fatty acids (SCFA) production by the gut microbiota. However, detailed knowledge of this process in the human intestine is lacking. We aimed to determine the acute fermentation kinetics of a FOS:GOS mixture in healthy males using a naso-intestinal catheter for sampling directly in the ileum or colon. We studied the fate of SCFA as substrates for glucose and lipid metabolism by the host after infusion of 13C-SCFA. In the human distal ileum, no fermentation of FOS:GOS, nor SCFA production, or bacterial cross-feeding was observed. The relative composition of intestinal microbiota changed rapidly during the test day, which demonstrates the relevance of postprandial intestinal sampling to track acute responses of the microbial community toward interventions. SCFA were vividly taken up and metabolized by the host as shown by incorporation of 13C in various host metabolites.

Heptanoate Improves Compensatory Mechanism of Glucose Homeostasis in Mitochondrial Long-Chain Fatty Acid Oxidation Defect.

Defects in mitochondrial fatty acid ß-oxidation (FAO) impair metabolic flexibility, which is an essential process for energy homeostasis. Very-long-chain acyl-CoA dehydrogenase (VLCADD; OMIM 609575) deficiency is the most common long-chain mitochondrial FAO disorder presenting with hypoglycemia as a common clinical manifestation. To prevent hypoglycemia, triheptanoin-a triglyceride composed of three heptanoates (C7) esterified with a glycerol backbone-can be used as a dietary treatment, since it is metabolized into precursors for gluconeogenesis. However, studies investigating the effect of triheptanoin on glucose homeostasis are limited. To understand the role of gluconeogenesis in the pathophysiology of long-chain mitochondrial FAO defects, we injected VLCAD-deficient (VLCAD-/-) mice with 13C3-glycerol in the presence and absence of heptanoate (C7). The incorporation of 13C3-glycerol into blood glucose was higher in VLCAD-/- mice than in WT mice, whereas the difference disappeared in the presence of C7. The result correlates with 13C enrichment of liver metabolites in VLCAD-/- mice. In contrast, the C7 bolus significantly decreased the 13C enrichment. These data suggest that the increased contribution of gluconeogenesis to the overall glucose production in VLCAD-/- mice increases the need for gluconeogenesis substrate, thereby avoiding hypoglycemia. Heptanoate is a suitable substrate to induce glucose production in mitochondrial FAO defect.

Abdominal Wall Thickness is a Predictor for Surgical Site Infections in Patients Undergoing Colorectal Operations.

BACKGROUND: Surgical site infections (SSIs) are an established complication following colorectal operations, with rates up to 30% reported in the literature. Obesity is a known risk factor for SSI; however, body mass index (BMI), body fat percentage, waist-hip ratio, or abdominal circumference are imperfect measures. The purpose of our study was to determine whether abdominal wall thickness (AWT) is predictive of SSI. METHODS: We queried our American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP) database for patients (age ≥18 years) undergoing a colectomy at the University of Kentucky (UK) from January 1, 2013 to December 31, 2018. The exclusion criteria included patients with open abdomens or the lack of preoperative computed tomography (CT) within 3 months of their operation. AWT was measured at the level of the anterior superior iliac spine (ASIS) on abdominal CT. SSI was defined by superficial SSI, deep SSI, and wound dehiscence. RESULTS: Of 1261 patients enrolled, 52.2% were female, with an average age of 57.4 years. More patients had laparoscopic operations (51%), and the median length of stay was 7 days. Our study demonstrated an SSI rate of 9.4% and a 30-day readmission rate of 11%. The overall mean AWT was 2.6 cm (range .1-13.1), and patients with the highest AWT quintile were more likely to develop an SSI than the lowest quintile (12% vs. 5%). After controlling for risk factors and confounders, the odds of an SSI were 3.6 times higher for patients with the highest AWT than patients with the lowest AWT. CONCLUSIONS: Among colorectal surgery patients, AWT is an independent risk factor predictive for SSI.

Inhibition of Fatty Acid Synthase Upregulates Expression of CD36 to Sustain Proliferation of Colorectal Cancer Cells.

Fatty acid synthase, a key enzyme of de novo lipogenesis, is an attractive therapeutic target in cancer. The novel fatty acid synthase inhibitor, TVB-3664, shows anti-cancer activity in multiple cancers including colorectal cancer; however, it is unclear whether uptake of exogeneous fatty acids can compensate for the effect of fatty acid synthase inhibition. This study demonstrates that inhibition of fatty acid synthase selectively upregulates fatty acid translocase (CD36), a fatty acid transporter, in multiple colorectal cancer models including colorectal cancer cells with shRNA mediated knockdown of fatty acid synthase and genetically modified mouse tissues with heterozygous and homozygous deletion of fatty acid synthase. Furthermore, human colorectal cancer tissues treated with TVB-3664 show a significant and selective upregulation of CD36 mRNA. shRNA-mediated knockdown of CD36 and inhibition of CD36 via sulfosuccinimidyl oleate, a chemical inhibitor of CD36, decreased cell proliferation in vitro and reduced tumor growth in subcutaneous xenograft models. Isogenic cell populations established from patient derived xenografts and expressing high levels of CD36 show a significantly increased ability to grow tumors in vivo. The tumor-promoting effect of CD36 is associated with an increase in the levels of pAkt and survivin. Importantly, combinatorial treatment of primary and established colorectal cancer cells with TVB-3664 and sulfosuccinimidyl oleate shows a synergistic effect on cell proliferation. In summary, our study demonstrates that upregulation of CD36 expression is a potential compensatory mechanism for fatty acid synthase inhibition and that inhibition of CD36 can improve the efficacy of fatty acid synthase-targeted therapy.

SK channel-mediated metabolic escape to glycolysis inhibits ferroptosis and supports stress resistance in C. elegans.

Metabolic flexibility is an essential characteristic of eukaryotic cells in order to adapt to physiological and environmental changes. Especially in mammalian cells, the metabolic switch from mitochondrial respiration to aerobic glycolysis provides flexibility to sustain cellular energy in pathophysiological conditions. For example, attenuation of mitochondrial respiration and/or metabolic shifts to glycolysis result in a metabolic rewiring that provide beneficial effects in neurodegenerative processes. Ferroptosis, a non-apoptotic form of cell death triggered by an impaired redox balance is gaining attention in the field of neurodegeneration. We showed recently that activation of small-conductance calcium-activated K+ (SK) channels modulated mitochondrial respiration and protected neuronal cells from oxidative death. Here, we investigated whether SK channel activation with CyPPA induces a glycolytic shift thereby increasing resilience of neuronal cells against ferroptosis, induced by erastin in vitro and in the nematode C. elegans exposed to mitochondrial poisons in vivo. High-resolution respirometry and extracellular flux analysis revealed that CyPPA, a positive modulator of SK channels, slightly reduced mitochondrial complex I activity, while increasing glycolysis and lactate production. Concomitantly, CyPPA rescued the neuronal cells from ferroptosis, while scavenging mitochondrial ROS and inhibiting glycolysis reduced its protection. Furthermore, SK channel activation increased survival of C. elegans challenged with mitochondrial toxins. Our findings shed light on metabolic mechanisms promoted through SK channel activation through mitohormesis, which enhances neuronal resilience against ferroptosis in vitro and promotes longevity in vivo.

Cancer stem cell marker expression alone and in combination with microvascular invasion predicts poor prognosis in patients undergoing transplantation for hepatocellular carcinoma.

BACKGROUND: The cancer stem cell hypothesis provides an explanation for hepatocellular carcinoma (HCC) heterogeneity. We investigated the expression of CD44 and CD133 alone and in combination with microvascular invasion (MVI) as predictors of prognosis in patients undergoing liver transplantation for HCC. METHODS: Explanted livers from 95 patients transplanted for HCC were analyzed. Marker expression was evaluated by immunofluorescence. RESULTS: Seventy-seven patients were male with a mean age of 56 years. The most common etiologies of cirrhosis were hepatitis C (50%) and alcoholic liver disease (41%). Forty-one patients had laboratory model for end-stage liver disease score greater than 15. Overall survival (OS) at 1-, 3-, and 5-years was 86%, 75%, and 64%, respectively. Recurrence rate was 13% with a median follow-up of 64 months. The 5-year OS was significantly lower in those patients with MVI and CD44 (36.9%) or CD133 (40%). CD44(+) and CD133(+) correlated with increased risk of poorly differentiated HCC, and elevated alpha-fetoprotein levels. In combination with MVI, both markers were independently associated with increased recurrence and worse OS (recurrence P < .003, odds ratio = 8.05; P = .001, odds ratio = 9.5, survival P = .001, HR = 3.7; P = .004, HR = 3.2 respectively). CONCLUSIONS: CD44 or CD133 alone and in combination with MVI are independent predictors of poor prognosis in patients undergoing transplantation for HCC.

Noggin attenuates cerulein-induced acute pancreatitis and impaired autophagy.

OBJECTIVES: To investigate the role of bone morphogenetic protein (BMP) signaling in acute pancreatitis (AP) by administration of noggin, an endogenous BMP antagonist, in a cerulein-induced AP model. METHODS: Acute pancreatitis was induced by 9 hourly intraperitoneal injections of cerulein (50 µg/kg). Control mice received phosphate-buffered saline injections. In a separate group, noggin (0.5 mg/kg) was given intraperitoneally at 1 hour before and 2, 4, and 6 hours after AP induction. The mice were euthanized at 1 hour after completion of AP induction. The blood samples and the pancreas were harvested for analysis. Isolated pancreatic acini from normal mice and AR42J cells were treated with BMP2 and cerulein. AR42J cells were also treated with noggin. Phosphorylation of Smad1/5/8 was measured. RESULTS: Bone morphogenetic protein signaling was up-regulated in AP mouse pancreas. Bone morphogenetic protein 2 and cerulein-induced phosphorylation of Smad1/5/8 in the acinar cells in vitro, which was blocked by noggin. Noggin administration in vivo attenuated AP induction, decreased vacuole formation in acinar cells, blocked LC3-II levels, and partially restored Beclin-1 and lysosomal-associated membrane protein 2 levels. CONCLUSIONS: Bone morphogenetic protein signaling seems to promote AP induction and autophagy, as suggested by our study showing that noggin ameliorates AP and partially restores autophagic homeostasis.