Hepatocellular carcinoma (HCC) cells are metabolically distinct from normal hepatocytes by expressing the high-affinity hexokinase (HK2) and suppressing glucokinase (GCK). This is exploited to selectively target HCC. Hepatic HK2 deletion inhibits tumor incidence in a mouse model of hepatocarcinogenesis. Silencing HK2 in human HCC cells inhibits tumorigenesis and increases cell death, which cannot be restored by GCK or mitochondrial binding deficient HK2. Upon HK2 silencing, glucose flux to pyruvate and lactate is inhibited, but TCA fluxes are maintained. Serine uptake and glycine secretion are elevated suggesting increased requirement for one-carbon contribution. Consistently, vulnerability to serine depletion increases. The decrease in glycolysis is coupled to elevated oxidative phosphorylation, which is diminished by metformin, further increasing cell death and inhibiting tumor growth. Neither HK2 silencing nor metformin alone inhibits mTORC1, but their combination inhibits mTORC1 in an AMPK-independent and REDD1-dependent mechanism. Finally, HK2 silencing synergizes with sorafenib to inhibit tumor growth.

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Maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. Unfortunately, for most fermentations, over one-third of sugar carbon is lost to CO2 due to the decarboxylation of pyruvate to acetyl-CoA and limitations in the reducing power of the bio-feedstock. Here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of organic (for example, sugars) and inorganic (for example, CO2) substrates in a single organism, can overcome these constraints to increase product yields and reduce overall CO2 emissions. As a proof-of-concept, Clostridium ljungdahlii was engineered to produce acetone and achieved a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (that is, H2) is provided, the fermentation emits no CO2. Finally, we show that mixotrophy is a general trait among acetogens.

Results suggested that a single intra-articular injection of autologous platelets resulted in significant improvements at 12 weeks in dogs with osteoarthritis involving a single joint.

SUMMARY BackgroundDrug-induced liver injury (DILI) is a significant cause of morbidity and mortality accounting for at least 13% of acute liver failure cases in the US. It is the leading cause of acute liver failure among patients referred for liver transplantation and the most common reason that drugs in development do not obtain FDA approval. The incidence of DILI has been reported to be one in 10 000 to one in 100 000 patients; however, the actual incidence is probably higher due in part to the difficulty of diagnosis.

In this work, we provide new insights into the metabolism of Clostridium acetobutylicum ATCC 824 obtained using a systematic approach for quantifying fluxes based on parallel labeling experiments and (13)C-metabolic flux analysis ((13)C-MFA). Here, cells were grown in parallel cultures with [1-(13)C]glucose and [U-(13)C]glucose as tracers and (13)C-MFA was used to quantify intracellular metabolic fluxes. Several metabolic network models were compared: an initial model based on current knowledge, and extended network models that included additional reactions that improved the fits of experimental data. While the initial network model did not produce a statistically acceptable fit of (13)C-labeling data, an extended network model with five additional reactions was able to fit all data with 292 redundant measurements. The model was subsequently trimmed to produce a minimal network model of C. acetobutylicum for (13)C-MFA, which could still reproduce all of the experimental data. The flux results provided valuable new insights into the metabolism of C. acetobutylicum. First, we found that TCA cycle was effectively incomplete, as there was no measurable flux between α-ketoglutarate and succinyl-CoA, succinate and fumarate, and malate and oxaloacetate. Second, an active pathway was identified from pyruvate to fumarate via aspartate. Third, we found that isoleucine was produced exclusively through the citramalate synthase pathway in C. acetobutylicum and that CAC3174 was likely responsible for citramalate synthase activity. These model predictions were confirmed in several follow-up tracer experiments. The validated metabolic network model established in this study can be used in future investigations for unbiased (13)C-flux measurements in C. acetobutylicum.

Background and Aims Telomere length has emerged as a promising risk predictor of various cancers including hepatocellular carcinoma (HCC). However, the majority of studies in this area measured telomere length in hepatocytes and one in lymphocytes with conflicting results. Moreover, no studies have been reported on using circulating DNA telomere length as a non-invasive HCC biomarker. Methods We conducted a nested case-control study to determine the relative telomere length (RTL) in serum DNA from 140 HBV-related HCC cases and 280 frequency-matched cancer-free HBV controls. Results Cases had a significantly longer RTL (median, 0.31; range, 0.02–2.31) than controls (median, 0.20; range, 0.01–1.60) (P=0.003). Consistently, longer RTLs conferred a significantly increased HCC risk compared to short RTLs in a univariate logistic regression analysis (odds ratio [OR]=1.55, 95% confidence interval [CI]=1.02–2.33, P=0.038). This association attenuated after multivariate adjustment (OR=1.40, 95% CI=0.90–2.19, P=0.132). In a quartile analysis, a significant dose-response relationship was noted in univariate analysis (Ptrend=0.017) which was again attenuated in multivariate analysis (Ptrend=0.079). Further analyses revealed that the significant association between serum RTL and HCC risk was evident in non-cirrhotic (OR=3.54, 95% CI 1.58–7.93 P=0.002), but not cirrhotic (OR=0.95, 95% CI 0.55–1.64, P=0.860) HBV patients. Moreover, the significantly increased HCC risk conferred by cirrhosis was modulated by RTL with a significant interaction effect (Pinteraction=0.013). Conclusions RTL in circulating cell-free serum DNA could potentially be used as a novel non-invasive biomarker for non-cirrhotic HCC. Prospective cohort studies are warranted to validate this finding and assess its clinical significance in HCC prevention.

Chronic hepatitis C virus (HCV) infection afflicts a reported 170 million people worldwide and is often complicated by cirrhosis and hepatocellular carcinoma. Morbidity and mortality are decreased with the successful treatment of chronic HCV infection. The current standard of care in the treatment for genotype 1 chronic HCV is pegylated interferon (IFN)-alfa, termed PEG, and ribavirin (RBV) in conjunction with a protease inhibitor, either telaprevir or boceprevir, which results in 67-75% sustained viral response rates. Increased understanding of the HCV has allowed further development of new direct-acting antiviral (DAA) agents against the HCV and has also allowed the development of IFN-free oral treatment regimens. We anticipate the approval in late 2013 of the first nucleotide polymerase inhibitor regimen with RBV alone for genotypes 2/3 and in combination with a 12-week regimen of PEG+RBV for genotypes 1, 4, 5, and 6. Most of the promising new DAA regimens are discussed herein.