IL-6 promotes head and neck tumor metastasis by inducing epithelial-mesenchymal transition via the JAK-STAT3-SNAIL signaling pathway

Epithelial-mesenchymal transition (EMT) is a key process in tumor metastatic cascade that is characterized by the loss of cell-cell junctions and cell polarity, resulting in the acquisition of migratory and invasive properties. However, the precise molecular events that initiate this complex EMT process in head and neck cancers are poorly understood. Increasing evidence suggests that tumor microenvironment plays an important role in promoting EMT in tumor cells. We have previously shown that head and neck tumors exhibit significantly higher Bcl-2 expression in tumor-associated endothelial cells and overexpression of Bcl-2 alone in tumor-associated endothelial cells was sufficient to enhance tumor metastasis of oral squamous cell carcinoma in a severe combined immunodeficient (SCID) mouse model. In this study, we show that endothelial cells expressing Bcl-2 (EC-Bcl-2), when cocultured with head and neck tumor cells (CAL27), significantly enhance EMT-related changes in tumor cells predominantly by the secretion of IL-6. Treatment with recombinant IL-6 or stable IL-6 overexpression in CAL27 cells or immortalized oral epithelial cells (IOE) significantly induced the expression of mesenchymal marker, vimentin, while repressing E-cadherin expression via the JAK/STAT3/Snail signaling pathway. These EMT-related changes were further associated with enhanced tumor and IOE cell scattering and motility. STAT3 knockdown significantly reversed IL-6-mediated tumor and IOE cell motility by inhibiting FAK activation. Furthermore, tumor cells overexpressing IL-6 showed marked increase in lymph node and lung metastasis in a SCID mouse xenograft model. Taken together, these results show a novel function for IL-6 in mediating EMT in head and neck tumor cells and increasing their metastatic potential.     

Effect of different types of conditioning contraction on upper body postactivation potentiation

Muscle contractions preceding an activity can result in increased force generation (postactivation potentiation [PAP]). Although the type of muscular contractions could affect subsequent strength and power performance, little information exists on their effects. The purpose of this study was to examine PAP effects produced by isometric (ISO), concentric (CON), eccentric (ECC), or concentric-eccentric (DYN) conditioning contractions on upper body force and power performance. Ten male, competitive rugby players (mean ± SD: age 20.4 ± 0.8 years, height 177.0 ± 8.1 cm, body mass 90.2 ± 13.8 kg) performed a ballistic bench press throw (BBPT) followed by a 10-minute rest and one of the conditioning contractions. After a 12-minute rest, the subjects performed another BBPT (post-BBPT). The conditioning contractions, applied on separate days and in counterbalanced randomized order, were a 7-second isometric barbell bench press for ISO and 1 set of 3 bench press repetitions at 3 repetition maximum for CON, ECC, and DYN (each repetition lasting 2 seconds for CON and ECC, overall execution time <7 seconds for DYN). Peak power (Ppeak), peak force (Fpeak), maximum distance (Dmax) and rate of force development (RFD) were measured using a linear position transducer. Electromyography (EMG) of the pectoralis major and triceps brachii was also recorded. The ISO produced significantly higher Ppeak (587 ± 116 and 605 ± 126 W for pre- and post-BBPT, respectively; p < 0.05). No significant differences in Ppeak were revealed for CON, ECC, and DYN (p > 0.05), and no significant differences existed in Fpeak, Dmax, and RFD for ISO, CON, ECC, and DYN (p > 0.05). Finally, EMG was not significantly different between pre- and post-BBPT for any of the conditioning contractions (p > 0.05). Isometric contractions appear to be the only conditioning contractions increasing upper body power output after long resting periods.     

The Arg482His mutation in the beta-galactosidase gene is responsible for a high frequency of GM1 gangliosidosis carriers in a Cypriot village

GM1 gangliosidosis is a lysosomal storage disorder caused by deficiency of beta-galactosidase. It is mainly characterized by progressive neurodegeneration, and in its most severe infantile form, it leads to death before the age of 4. The GLB1 gene gives rise to two alternatively spliced mRNAs that encode the beta-galactosidase and the elastin binding protein (EBP). The diagnosis of two patients with the infantile form of GM1 gangliosidosis and 11 carriers in a small mountainous village in Cyprus prompted us to carry out a study in order to establish the frequency of carriers in the village and identify the mutations involved. Carrier detection was initially based on the measurement of beta-galactosidase activity in leucocytes. Among 85 random samples from the village, 10 were classified as carriers. Sequencing of the GLB1 gene in a Cypriot patient identified the missense mutation c.1445G>A (p.Arg482His) in the homozygous state. Seven of the 10 carriers identified using the enzyme assay were found to carry the same mutation by NspI restriction enzyme analysis. The three individuals who were negative for the c.1445G>A had borderline enzyme results and were probably wrongly classified as carriers. The frequency of GM1 gangliosidosis carriers in this village is approximately 8% (1:12). Western blot analysis showed a marked decrease of the 64-kDa mature form of the enzyme protein and a similar reduction of the 67-kDa EBP. Our results indicate that the c.1445G>A mutation, which appears to be responsible for all GM1 gangliosidosis alleles in this Cypriot village, affects protein conformation.     

Somatic and intramuscular distribution of muscle spindles and their relation to muscular angiotypes

The distribution pattern of muscle spindles in the skeletal musculature has been reviewed in a large number of muscles (using the literature data especially from cat and man), and the relation of spindle content to muscle mass was quantitatively examined in 36 cat and 140 human muscles. In both species, the number of spindles increases with increasing muscle mass in a power law fashion of the form y=bx+a, whereby y denotes the logarithm of spindle content within a muscle, and x is the logarithm of muscle mass. For the cat, slope b and intercept a were estimated as 0.39 and 1.53, and for man as 0.48 and 1.33, respectively. The results show that the spindle content of a muscle may be related to its mass, confirming a similar analysis made previously by Banks and Stacey (Mechano receptors, Plenum Press, New York, 1988, pp. 263-269) in a different data set. With regard to the histological profile of muscle fibers, (as it is already well documented by many groups) muscle spindles tend to be located in deeper muscle regions where oxidative fibers predominate, and are far scarcer in superficial and flat muscle regions where glycolytic fibers predominate. These discrete muscle regions differ also in the properties of the vessel tree supplying them, for which the term oxidative and glycolytic "angiotype" has been used. The results from these three aspects of analysis (relation to muscle mass, relation to muscle regions with high oxidative index and relation to muscle regions with dense vascular supply) were combined with histological findings showing that spindles may be in systematic anatomical contact to intramuscular vessels. Based on these data a hypothesis is proposed according to which, both the number and intramuscular placement of muscle spindles are related to the oxidative angiotype supplying the muscle territories rich in oxidative fibers. The hypothesis is discussed.     

Bcl-2 but not clusterin/apolipoprotein J protected human diploid fibroblasts and immortalized keratinocytes from ceramide-induced apoptosis: role of p53 in the ceramide response

The role of clusterin/apolipoprotein J (Clu/ApoJ) and Bcl-2 on C(2)-ceramide-induced apoptosis of embryonic human diploid fibroblasts, MRC-5 and immortalized adult skin keratinocytes, HaCaT was investigated. C(2)-ceramide-induced apoptosis of HaCaT in a time- and dose-dependent manner, while in MRC-5 only at higher concentrations. There was a dose-dependent accumulation of Clu/ApoJ and downregulation of Bcl-2 which correlated with C(2)-ceramide-induced apoptosis of MRC-5. While overexpression of Bcl-2 suppressed C(2)-ceramide-mediated apoptosis in both cell types, Clu/ApoJ failed to do so, accessed by morphological changes, DNA fragmentation and PARP cleavage. There was no change in the expression of endogenous p53 or p21(Waf1/Cip1) upon C(2)-ceramide treatment of MRC-5. However, mutant p53(143ala) increased the sensitivity of MRC-5 to C(2)-ceramide-induced apoptosis by markedly downregulating Bcl-2, pointing to a role for p53. These results suggested that whereas downregulation of Bcl-2 may be a crucial factor involved in C(2)-ceramide-induced apoptosis, accumulation of Clu/ApoJ may be a signal of stress response. Moreover, the ceramide-activated apoptotic pathway may be regulated by p53.     

The canonical NF-κB pathway differentially protects normal and human tumor cells from ROS-induced DNA damage

DNA damage responses (DDR) invoke senescence or apoptosis depending on stimulus intensity and the degree of activation of the p53-p21(Cip1/Waf1) axis; but the functional impact of NF-κB signaling on these different outcomes in normal vs. human cancer cells remains poorly understood. We investigated the NF-κB-dependent effects and mechanism underlying reactive oxygen species (ROS)-mediated DDR outcomes of normal human lung fibroblasts (HDFs) and A549 human lung cancer epithelial cells. To activate DDR, ROS accumulation was induced by different doses of H(2)O(2). The effect of ROS induction caused a G2 or G2-M phase cell cycle arrest of both human cell types. However, ROS-mediated DDR eventually culminated in different end points with HDFs undergoing premature senescence and A549 cancer cells succumbing to apoptosis. NF-κB p65/RelA nuclear translocation and Ser536 phosphorylation were induced in response to H(2)O(2)-mediated ROS accumulation. Importantly, blocking the activities of canonical NF-κB subunits with an IκBα super-repressor or suppressing canonical NF-κB signaling by IKKβ knock-down accelerated HDF premature senescence by up-regulating the p53-p21(Cip1/Waf1) axis; but inhibiting the canonical NF-κB pathway exacerbated H(2)O(2)-induced A549 cell apoptosis. HDF premature aging occurred in conjunction with γ-H2AX chromatin deposition, senescence-associated heterochromatic foci and beta-galactosidase staining. p53 knock-down abrogated H(2)O(2)-induced premature senescence of vector control- and IκBαSR-expressing HDFs functionally linking canonical NF-κB-dependent control of p53 levels to ROS-induced HDF senescence. We conclude that IKKβ-driven canonical NF-κB signaling has different functional roles for the outcome of ROS responses in the contexts of normal vs. human tumor cells by respectively protecting them against DDR-dependent premature senescence and apoptosis.     

Cytochrome P450 1A1 (CYP1A1) gene polymorphisms and ovarian cancer risk: a meta-analysis

This meta-analysis aims to examine whether the genotype status of MspI, Ile462Val, and Thr461Asn polymorphisms in Cytochrome P450 1A1 (CYP1A1) is associated with ovarian cancer risk. Eligible case-control studies were identified through search in MEDLINE (end of search: October 2010). Pooled odds ratios (ORs) were appropriately derived from fixed effects or random effects models. Concerning MspI polymorphism, seven studies were eligible (1,051 cases and 1,613 controls); 11 studies were eligible (1,680 cases and 3,345 controls) for Ile462Val and three studies were eligible (349 cases and 785 controls) for Thr461Asn. Ile462Val polymorphism seemed to confer elevated ovarian cancer risk concerning homozygous carriers (pooled OR?=?2.65, 95?% CI: 1.40-5.03, p?=?0.003, fixed effects), as well as at the recessive model (pooled OR?=?2.10, 95?% CI: 1.13-3.92, p?=?0.020, fixed effects); these findings were replicated upon Caucasian subjects. MspI polymorphism was not associated with ovarian cancer risk (for heterozygous TC vs TT carriers pooled OR?=?1.10, 95?% CI: 0.91-1.34, p?=?0.329, fixed effects; for homozygous CC vs. TT carriers pooled OR?=?1.11, 95?% CI: 0.65-1.90, p?=?0.693, fixed effects). With respect to Thr461Asn polymorphism a finding of borderline statistical significance emerged, pointing to marginally elevated ovarian cancer risk in heterozygous Thr/Asn carriers (pooled OR?=?1.62, 95?% CI: 0.97-2.70, p?=?0.066, fixed effects), but not in homozygous Asn/Asn carriers (pooled OR?=?1.40, 95?% CI: 0.18-10.89, p?=?0.749, fixed effects). Ile462Val status seems to represent a meaningful risk factor for ovarian cancer in Caucasians. Additional case-control studies of high methodological quality are needed in order to further substantiate and enrich the present findings. Special attention should be paid upon the design of future studies; Asian and African populations should represent points of focus.     

Endogenous growth hormone and insulin after interposition of a reversed jejunal segment in short bowel syndrome. An experimental study on pigs

ABSTRACT: BACKGROUND: Interposition of a reversed jejunal loop in short bowel sydrome has previously been investigated in human along with animal models and seemed able to facilitate intestinal adaptation. However, it is unclear if growth hormone and insulin, well known for their implication in short bowel pathophysiology, intervene on this effect. FINDINGS: Porcine models were randomly allocated to two cohorts: (1) short bowel (SB) group (n = 8) and (2) short bowel reverse jejunal segment (SB-RS) group (n = 8). Amongst other parameters serum growth hormone and insulin were measured at baseline, as well as on postoperative day 30 and 60. CONCLUSION: Both endogenous hormones failed to demonstrate significant difference in respect to potential direct effect to mechanisms of enhanced intestinal adaptation in reversed group.