Targeting Insulin-Like Growth Factor 1 Receptor Inhibits Pancreatic Cancer Growth and Metastasis

Pancreatic cancer is one of the most lethal cancers. Increasing incidence and mortality indicates that there is still much lacking in detection and management of the disease. This is partly due to a lack of specific symptoms during early stages of the disease. Several growth factor receptors have been associated with pancreatic cancer. Here, we have investigated if an RNA interference approach targeted to IGF-IR could be effective and efficient against pancreatic cancer growth and metastasis. For that, we evaluated the effects of IGF-1R inhibition using small interfering RNA (siRNAs) on tumor growth and metastasis in HPAC and PANC-1 pancreatic cancer cell lines. We found that silencing IGF-1R inhibits pancreatic cancer growth and metastasis by blocking key signaling pathways such AKT/PI3K, MAPK, JAK/STAT and EMT. Silencing IGF-1R resulted in an anti-proliferative effect in PANC-1 and HPAC pancreatic cancer cell lines. Matrigel invasion, transwell migration and wound healing assays also revealed a role for IGF-1R in metastatic properties of pancreatic cancer. These results were further confirmed using Western blotting analysis of key intermediates involved in proliferation, epithelial mesenchymal transition, migration, and invasion. In addition, soft agar assays showed that silencing IGF-1R also blocks the colony forming capabilities of pancreatic cancer cells in vitro. Western blots, as well as, flow cytometric analysis revealed the induction of apoptosis in IGF-1R silenced cells. Interestingly, silencing IGF-1R also suppressed the expression of insulin receptor β. All these effects together significantly control pancreatic cancer cell growth and metastasis. To conclude, our results demonstrate the significance of IGF-1R in pancreatic cancer.     

Recombination networks as genetic markers in a human variation study of the Old World

We have analyzed human genetic diversity in 33 Old World populations including 23 populations obtained through Genographic Project studies. A set of 1,536 SNPs in five X chromosome regions were genotyped in 1,288 individuals (mostly males). We use a novel analysis employing subARG network construction with recombining chromosomal segments. Here, a subARG is constructed independently for each of five gene-free regions across the X chromosome, and the results are aggregated across them. For PCA, MDS and ancestry inference with STRUCTURE, the subARG is processed to obtain feature vectors of samples and pairwise distances between samples. The observed population structure, estimated from the five short X chromosomal segments, supports genome-wide frequency-based analyses: African populations show higher genetic diversity, and the general trend of shared variation is seen across the globe from Africa through Middle East, Europe, Central Asia, Southeast Asia, and East Asia in broad patterns. The recombinational analysis was also compared with established methods based on SNPs and haplotypes. For haplotypes, we also employed a fixed-length approach based on information-content optimization. Our recombinational analysis suggested a southern migration route out of Africa, and it also supports a single, rapid human expansion from Africa to East Asia through South Asia.     

The genetic architecture of tristyly and its breakdown to self‐fertilization

The floral polymorphism tristyly involves three style morphs with a reciprocal arrangement of stigma and anther heights governed by two diallelic loci (S and M). Tristyly functions to promote cross‐pollination, but modifications to stamen position commonly cause transitions to selfing. Here, we integrate whole‐genome sequencing and genetic mapping to investigate the genetic architecture of the M locus and the genetic basis of independent transitions to selfing in tristylous Eichhornia paniculata. We crossed independently derived semi‐homostylous selfing variants of the long‐ and mid‐styled morph fixed for alternate alleles at the M locus (ssmm and ssMM, respectively), and backcrossed the F₁ to the parental ssmm genotype. We phenotyped and genotyped 462 backcross progeny using 1450 genotyping‐by‐sequencing (GBS) markers and performed composite interval mapping to identify quantitative trait loci (QTL) governing style‐length and anther‐height variation. A QTL associated with the primary style‐morph differences (style length and anther height) mapped to linkage group 5 and spanned ~13–27.5 Mbp of assembled sequence. Bulk segregant analysis identified 334 genes containing SNPs potentially linked to the M locus. The stamen modifications characterizing each selfing variant were governed by loci on different linkage groups. Our results provide an important step towards identifying the M locus and demonstrate that transitions to selfing have originated by independent sets of mating‐system modifier genes unlinked to the M locus, a pattern inconsistent with a recombinational origin of selfing variants at a putative supergene.     

Genetic analysis of OCT1 gene polymorphisms in an Indian population

BACKGROUND:

Genetic variants of the organic cation transporter (OCT1) gene could influence interindividual variation in clinical response to metformin therapy. The genetic basis for the single-nucleotide polymorphism (SNP) of OCT1 gene has been established in other populations, but it remains to be elucidated in the Indian population. This study is focused on OCT1 gene variants rs2282143 (P341L, 1022C>T), rs628031 (M408V, 1222A>G) and rs622342 (1386C>A) frequency distributions in the South Indian Tamilian population.

MATERIALS AND METHODS:

A total of 112 unrelated healthy subjects of South Indian Tamilian origin, aged 18–60 years, of either sex were recruited for the study. Genotyping was determined using the quantitative real time-polymerase chain reaction and polymerase chain reaction followed by restriction fragment length polymorphism methods.

RESULTS:

Allele frequencies of rs2282143, rs628031and rs622342 polymorphisms were 8.9%, 80.3% and 24.5%, respectively. Interethnic differences in the genotype and allele frequencies of OCT1 gene polymorphism were observed when compared with other major populations. The SNPs rs2282143, T allele and rs628031, G allele were more common in Asians (5.5–16.8% and 76.2–81%) and African Americans (8.2% and 73.5%) than in Caucasians (0–2% and 57.4–60%).

CONCLUSION:

This is the first time the frequency of OCT1 gene polymorphism was determined in the Indian population, and is similar to the frequencies observed in African-Americans and other Asian populations but different from those in Caucasians. The data observed in this study would justify further pharmacogenetic studies to potentially evaluate the role of OCT1 gene polymorphism in the therapeutic efficacy of metformin.     

The Evolution of Selfing Is Accompanied by Reduced Efficacy of Selection and Purging of Deleterious Mutations

The transition from outcrossing to selfing is predicted to reduce the genome-wide efficacy of selection because of the lower effective population size (N_e) that accompanies this change in mating system. However, strongly recessive deleterious mutations exposed in the homozygous backgrounds of selfers should be under strong purifying selection. Here, we examine estimates of the distribution of fitness effects (DFE) and changes in the magnitude of effective selection coefficients (N_es) acting on mutations during the transition from outcrossing to selfing. Using forward simulations, we investigated the ability of a DFE inference approach to detect the joint influence of mating system and the dominance of deleterious mutations on selection efficacy. We investigated predictions from our simulations in the annual plant Eichhornia paniculata, in which selfing has evolved from outcrossing on multiple occasions. We used range-wide sampling to generate population genomic datasets and identified nonsynonymous and synonymous polymorphisms segregating in outcrossing and selfing populations. We found that the transition to selfing was accompanied by a change in the DFE, with a larger fraction of effectively neutral sites (N_es < 1), a result consistent with the effects of reduced N_e in selfers. Moreover, an increased proportion of sites in selfers were under strong purifying selection (N_es > 100), and simulations suggest that this is due to the exposure of recessive deleterious mutations. We conclude that the transition to selfing has been accompanied by the genome-wide influences of reduced N_e and strong purifying selection against deleterious recessive mutations, an example of purging at the molecular level.     

Differential effect of chromium compounds on the immune response of the African mouth breeder Oreochromis mossambicus (Peters)

The objective of this study was to investigate the effect of trivalent (chromic chloride) and hexavalent (potassium dichromate) forms of chromium in the African mouth breeder Oreochromis mossambicus (Peters), with reference to the humoral immune response and lymphoid cells/organs. The 96 h LD50 for hexavalent and trivalent chromium was found to be 75 and 1,000microg fish(-1), respectively. Groups of fishes were injected intraperitoneally with 10, 1, 0.1 and 0.01% LD50 hexavalent and trivalent forms of chromium and subsequently immunised with bovine serum albumin (5 mg in 0.2 ml physiological saline). Both forms of chromium suppressed the antibody response, with hexavalent chromium being more suppressive than trivalent chromium. Reduction in spleen weight, splenocyte number and the percentage of blood lymphocytes was observed following administration of both forms of chromium. The possible immunological mechanisms behind the differential suppression of the antibody response and the reduction in spleen weight, splenocyte and lymphocyte counts are discussed.     

Annexin II-mediated plasmin generation activates TGF-beta3 during epithelial-mesenchymal transformation in the developing avian heart

Epithelial-mesenchymal transformation (EMT), the process by which epithelial cells are converted into motile, invasive mesenchymal cells, is critical to valvulogenesis. Transforming growth factor-beta3 (TGF-beta3), an established mediator of avian atrioventricular (AV) canal EMT, is secreted as a latent complex. In vitro, plasmin-mediated proteolysis has been shown to release active TGF-betas from the latent complex. Annexin II, a co-receptor for tissue plasminogen activator (tPA) and plasminogen, promotes cell-surface generation of the serine protease plasmin. Here, we show that annexin II-mediated plasmin activity regulates release of active TGF-beta3 during chick AV canal EMT. Primary embryonic endocardial-derived cells express annexin II which promotes plasminogen activation in vitro. Incubation of heart explant cultures with either alpha(2)antiplasmin (alpha(2)AP), a major physiological plasmin inhibitor, or anti-annexin II IgG, blocked EMT by approximately 80%, and 50%, respectively. Anti-annexin II IgG-mediated inhibition of EMT was overcome by the addition of recombinant TGF-beta3. Upon treatment with anti-annexin II IgG or alpha(2)AP, conditioned medium from heart explant cultures showed absence of the active fragment of TGF-beta3 by Western blot analysis and a approximately 50% decrease in TGF-beta specific bioactivity. Our results suggest that annexin II-mediated plasmin activity regulates the release of active TGF-beta during cardiac valve development in the avian heart.     

Fast Charge-Transfer Rates in Li-CO2 Batteries with a Coupled Cation-Electron Transfer Process

Li-CO₂ batteries with a high theoretical energy density (1876 Wh kg⁻¹) have unique benefits for reversible carbon fixation for energy storage systems. However, due to lack of stable and highly active catalysts, the long-term operation of Li-CO₂ batteries is limited to low current densities (mainly <0.2 mA cm⁻²) that are far from practical conditions. In this work, it is discovered that, with an ionic liquid-based electrolyte, highly active and stable transition metal trichalcogenide alloy catalysts of Sb_0.67Bi_1.33X₃ (X = S, Te) enable operation of the Li-CO₂ battery at a very high current rate of 1 mA cm⁻² for up to 220 cycles. It is revealed that: i) the type of chalcogenide (Te vs S) significantly affects the electronic and catalytic properties of the catalysts, ii) a coupled cation-electron charge transfer process facilitates the carbon dioxide reduction reaction (CO₂RR) occurring during discharge, and iii) the concentration of ionic liquid in the electrolyte controls the number of participating CO₂ molecules in reactions. A combination of these key factors is found to be crucial for a successful operation of the Li-CO₂ chemistry at high current rates. This work introduces a new class of catalysts with potential to fundamentally solve challenges of this type of batteries.     

Oligomerization of acidic fibroblast growth factor is not a prerequisite for its cell proliferation activity

Oligomerization of fibroblast growth factors (FGFs) induced on binding to heparin or heparan sulfate proteoglycan is considered to be crucial for receptor activation and initiation of biological responses. To gain insight into the mechanism of activation of the receptor by FGFs, in the present study we investigate the effect(s) of interaction of a heparin analog, sucrose octasulfate (SOS), on the structure, stability, and biological activities of a recombinant acidic FGF from Notophthalmus viridescens (nFGF-1). SOS is found to bind to nFGF-1 and significantly increase the thermodynamic stability of the protein. Using a variety of techniques such as size-exclusion chromatography, sedimentation velocity, and multidimensional nuclear magnetic resonance (NMR) spectroscopy, it is shown that binding of SOS to nFGF-1 retains the protein in its monomeric state. In its monomeric state (complexed to SOS), n-FGF-1 shows significant cell proliferation activity. (15)N and (1)H chemical shift perturbation and the intermolecular nuclear Overhauser effects (NOEs) between SOS and nFGF-1 reveal that the ligand binds to the dense, positively charged cluster located in the groove enclosed by beta-strands 10 and 11. In addition, molecular modeling based on the NOEs observed for the SOS-nFGF-1 complex, indicates that SOS and heparin share a common binding site on the protein. In conclusion, the results of the present study clearly show that heparin-induced oligomerization of nFGF-1 is not mandatory for its cell proliferation activity.