Genomic organization and expression of immunoglobulin genes in the Chinese hamster (Cricetulus griseus)

In science, the hamsters are widely used as a model for studying the human diseases because they display many features like humans. The utility of the Chinese hamster as a biology model can be further enhanced by further characterization of the genes encoding components of the immune system. Here, we report the genomic organization and expression of the Chinese hamster immunoglobulin heavy and light chain genes. The Chinese hamster IgH locus contains 268 VH segments (132 potentially functional genes, 12 ORFs and 124 pseudogenes), 4 DH segments, 6 JH segments, four constant region genes (μ, γ, ε and α) and one reverse δ remnant fragment. The Igκ locus contains only a single Cκ gene, 4 Jκ segments and 48 Vκ segments (15 potentially functional genes and 33 pseudogenes), whereas the Igλ locus contains 4 Cλ genes, but only Cλ 3 and Cλ 4 each preceded by a Jλ gene segment. A total of 49 Vλ segments (39 potentially functional genes, 3 ORFs and 7 pseudogenes) were identified. Analysis of junctions of the recombined V(D)J transcripts reveals complex diversity in both expressed H and κ sequences, but the microhomology-directed VJ recombination obviously results in very limited diversity in the Chinese hamster λ gene despite more potential germline-encoded combinatorial diversity. This is the first study to make a comprehensive analysis of the Ig genes in the Chinese hamster, which provides insights into the Ig genes in placental mammals.

Cancer systems biology: embracing complexity to develop better anticancer therapeutic strategies

The transformation of normal cells into cancer cells and maintenance of the malignant state and phenotypes are associated with genetic and epigenetic deregulations, altered cellular signaling responses and aberrant interactions with the microenvironment. These alterations are constantly evolving as tumor cells face changing selective pressures induced by the cells themselves, the microenvironment and drug treatments. Tumors are also complex ecosystems where different, sometime heterogeneous, subclonal tumor populations and a variety of nontumor cells coexist in a constantly evolving manner. The interactions between molecules and between cells that arise as a result of these alterations and ecosystems are even more complex. The cancer research community is increasingly embracing this complexity and adopting a combination of systems biology methods and integrated analyses to understand and predictively model the activity of cancer cells. Systems biology approaches are helping to understand the mechanisms of tumor progression and design more effective cancer therapies. These approaches work in tandem with rapid technological advancements that enable data acquisition on a broader scale, with finer accuracy, higher dimensionality and higher throughput than ever. Using such data, computational and mathematical models help identify key deregulated functions and processes, establish predictive biomarkers and optimize therapeutic strategies. Moving forward, implementing patient-specific computational and mathematical models of cancer will significantly improve the specificity and efficacy of targeted therapy, and will accelerate the adoption of personalized and precision cancer medicine.

Fatty and lean red meat consumption in China: differential association with Chinese abdominal obesity

AIM

We examined the longitudinal association between red meat (RM) consumption and the risk of abdominal obesity in Chinese adults.

METHODS AND RESULTS

Our data are from 16,822 adults aged 18-75 in the China Health and Nutrition Survey from 1993 to 2011. We assessed RM intake with three 24-h dietary recalls. We defined abdominal obesity as a waist circumference (WC) ≥85 centimeters (cm) for men and ≥80 cm for women. Multilevel mixed-effect regression models showed that men experienced WC increases of 0.74 cm (95% confidence interval [CI]: 0.39-1.09) from a higher total intake of fresh RM and 0.59 cm (95% CI: 0.24-0. 95) from a higher intake of fatty fresh RM but 0.14 cm (95% CI: -0.39 to 0.66) from a higher intake of lean fresh RM in the top quartile versus non-consumers when adjusted for potential confounders. In contrast, after additional adjustment for baseline WC, the odds ratios of abdominal obesity in men were attenuated for total fresh RM (1.25 [95% CI: 1.06-1.47]) and fatty fresh RM (1.22 [95% CI: 1.03-1.44]) but were still not affected by lean fresh RM (0.95 [95% CI: 0.75-1.22]). Women also showed a positive association of fatty fresh RM intake with abdominal obesity.

CONCLUSION

Greater intake of fatty fresh RM was significantly associated with higher WC (men only) and abdominal obesity risk in Chinese adults. The gender-specific differential association of fatty versus lean fresh RM warrants further study.

The prevalence of Parkinson's disease continues to rise after 80 years of age: a cross-sectional study of Chinese veterans

OBJECTIVE

The purpose of this study was to examine whether the prevalence of Parkinson's disease (PD) continues to rise after 80 years of age.

METHODS

This is a two-stage, multi-center, cross-sectional study using a stratified cluster sampling approach was employed. Subjects included veterans at ≥ 60 years of age living in veterans' communities for at least one month in 18 major cities across China. In the first step, possible PD was screened using a PD screening scale. Demographic and relevant information were collected. In the second step, PD diagnosis was established using the United Kingdom Parkinson's Disease Society Brain Bank (UKPDSBB) diagnostic criteria.

RESULTS

The study was conducted during the period from December 2009 to December 2012. The study included 277 veterans' communities. Among the approached 11,593 subjects, 9676 subjects, (9096 men, 580 women) responded. The response rate was 83.46%.The age was ≥ 80 years in 6722 (69.47%) subjects. A diagnosis of PD was established in 228 subjects (2.36%) in the entire sample. The rate of PD was 2.65% in those with an age of ≥ 80 years. The rate of PD increased with increasing age (0%, 1.84%, 2.60% and 3.68% in the subjects at < 70, 70-79, 80-89 and ≥ 90 years of age, respectively; χ2 = 10.891, p = 0.001 in chi-square test). The rate of PD was higher in men (2.44%) than in women (1.46%) on the surface. However, no significant difference was detected (p = 0.241).

CONCLUSIONS

The prevalence of PD continues to increase beyond the age of 80 years. The prevalence of PD in Chinese veterans is not lower than that in other countries and regions.

mTOR regulates DNA damage response through NF-κB-mediated FANCD2 pathway in hematopoietic cells

Hematopoietic stem/progenitor cells (HSPCs) function to give rise to mature blood cells. Effective DNA damage response (DDR) and maintenance of genomic stability are crucial for normal functioning of HSPCs. Mammalian target of rapamycin (mTOR) integrates signals from nutrients and growth factors to control protein synthesis, cell growth, survival and metabolism, and has been shown to regulate DDR in yeast and human cancer cells through the p53/p21 signaling cascade. Here, we show that gene targeting of mTOR in HSPCs causes a defective DDR due to a variety of DNA damage agents, mimicking that caused by deficient FANCD2, a key component of the Fanconi anemia (FA) DDR machinery. Mechanistically, mTOR(-/-) HSPCs express drastically reduced FANCD2. Consistent with these genetic findings, inactivation of mTOR in human lymphoblast cells by pp242 or Torin 1, mTOR kinase inhibitors, suppresses FANCD2 expression and causes a defective DDR that can be rescued by reconstitution of exogenous FANCD2. Further mechanistic studies show that mTOR deficiency or inactivation increases phosphorylation and nuclear translocation of nuclear factor (NF)-κB, which results in an enhanced NF-κB binding to FANCD2 promoter to suppress FANCD2 expression. Thus, mTOR regulates DDR and genomic stability in hematopoietic cells through a noncanonical pathway involving NF-κB-mediated FANCD2 expression.

Fanconi anemia pathway--the way of DNA interstrand cross-link repair

The study of rare genetic diseases usually inspires the research of cancer biology. Fanconi anemia (FA), is a rare cancer susceptibility syndrome with an incidence of only 1 per 350,000 births. FA is an autosomal recessive disease with three main features: chromosome instability, hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC), cisplatin and so on, and susceptible to a number of cancer types, mainly leukemia and squamous cell carcinomas of the head and neck or gynecologic system. DNA crosslinking agents may led to DNA cross-linking lesion, and Fanconi anemia pathway plays a key role in repairing its cross-linking. However, FA pathway is closely linked with carcinogenesis and tumor drug resistance. This paper mainly focuses on the FA pathway and its progress in cancer research.

The antitumor natural compound falcarindiol promotes cancer cell death by inducing endoplasmic reticulum stress

Falcarindiol (FAD) is a natural polyyne with various beneficial biological activities. We show here that FAD preferentially kills colon cancer cells but not normal colon epithelial cells. Furthermore, FAD inhibits tumor growth in a xenograft tumor model and exhibits strong synergistic killing of cancer cells with 5-fluorouracil, an approved cancer chemotherapeutic drug. We demonstrate that FAD-induced cell death is mediated by induction of endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR). Decreasing the level of ER stress, either by overexpressing the ER chaperone protein glucose-regulated protein 78 (GRP78) or by knockout of components of the UPR pathway, reduces FAD-induced apoptosis. In contrast, increasing the level of ER stress by knocking down GRP78 potentiates FAD-induced apoptosis. Finally, FAD-induced ER stress and apoptosis is correlated with the accumulation of ubiquitinated proteins, suggesting that FAD functions at least in part by interfering with proteasome function, leading to the accumulation of unfolded protein and induction of ER stress. Consistent with this, inhibition of protein synthesis by cycloheximide significantly decreases the accumulation of ubiquitinated proteins and blocks FAD-induced ER stress and cell death. Taken together, our study shows that FAD is a potential new anticancer agent that exerts its activity through inducing ER stress and apoptosis.

ADAMTS9 is a functional tumor suppressor through inhibiting AKT/mTOR pathway and associated with poor survival in gastric cancer

Using genome-wide promoter methylation analysis, we identified a disintegrin-like and metalloprotease with thrombospondin type 1 motif 9 (ADAMTS9) is methylated in cancer. We aim to clarify its epigenetic inactivation, biological function and clinical implication in gastric cancer. ADAMTS9 was silenced in 6 out of 8 gastric cancer cell lines. The loss of ADAMTS9 expression was regulated by promoter hypermethylation and could be restored by demethylation agent. Ectopic expression of ADAMTS9 in gastric cancer cell lines (AGS, BGC823) inhibited cell growth curve in both the cell lines (P<0.0001), suppressed colony formation (P<0.01) and induced apoptosis (P<0.001 in AGS, P<0.01 in BGC823). Moreover, conditioned culture medium from ADAMTS9-transfected cell lines significantly disrupted the human umbilical vein endothelial cell tube formation capacity on Matrigel (P<0.01 in AGS, P<0.001 in BGC823). The in vivo growth of ADAMTS9 cells in nude mice was also markedly diminished after stable expression of ADAMTS9 (P<0.001). On the other hand, ADAMTS9 knockdown promoted cell proliferation (P<0.001). We further revealed that ADAMTS9 inhibited tumor growth by blocking activation of Akt and its downstream target the mammalian target of rapamycin (mTOR). ADAMTS9 also reduced phosphorylation of mTOR downstream targets p70 ribosomal S6 kinase, eIF4E-binding protein and downregulated hypoxia-inducible factor-1α. Therefore, this is the first demonstration that ADAMTS9 is a critical tumor suppressor of gastric cancer progression at least in part through suppression of oncogenic AKT/mTOR signaling. Moreover, promoter methylation of ADAMTS9 was detected in 29.2% (21/72) of primary gastric tumors. Multivariate analysis showed that patients with ADAMTS9 methylation had a poorer overall survival (relative risk (RR)=2.788; 95% confidence interval, 1.474-5.274; P=0.002). Kaplan-Meier survival curves showed that ADAMTS9 methylation was significantly associated with shortened survival in gastric cancer patients (P=0.001, log-rank test). In conclusion, ADAMTS9 acts as a functional tumor suppressor in gastric cancer through inhibiting oncogenic AKT/mTOR signaling pathway. Methylation of ADAMTS9 is an independent prognostic factor of gastric cancer.

Changes in Spontaneous Dorsal Horn Potentials after Dorsal Root Entry Zone Lesioning in Patients with Pain after Brachial Plexus Avulsion

OBJECTIVES: This study investigated spontaneous dorsal horn potentials in patients with pain after brachial plexus avulsion and determined the effect of dorsal root entry zone (DREZ) lesioning on these potentials and on pain levels. METHODS: Electrospinography (ESG) recordings were undertaken in seven patients using a noninvasive electrocorticography strip electrode. Measurements were taken from the DREZ on the intact side of the spinal cord before lesioning of the injured DREZ and from the injured DREZ before and after lesioning. RESULTS: DREZ lesioning had a significant positive effect on pain at 12 months postoperatively. At 15.0 Hz, the mean ESG power from the injured DREZ before lesioning was significantly higher than that from the intact DREZ. In addition, the mean ESG power from the injured DREZ after successful DREZ lesioning was significantly lower than that from the intact DREZ and that from the injured DREZ before lesioning. CONCLUSIONS: The ESG power from the injured DREZ increases in patients with pain after brachial plexus avulsion compared with that of the intact DREZ; this increase is reduced by successful DREZ lesioning.