STAT3 inhibitor enhances chemotherapy drug efficacy by modulating mucin 1 expression in non-small cell lung carcinoma

Purpose: To evaluate the role of signal transducer and activator of transcription 3 (STAT3) and mucin 1(MUC1) in non-small cell lung carcinoma (NSCLC) and the use of their inhibitors to reduce chemoresistance.Methods: Cisplatin or vinblastine was provided either with or without STAT3 inhibitor and evaluated for chemoresistance in NSCLC cells and a xenograft mice tumor model. Immunohistochemistry and Kaplan-Meier method of survival analysis were used to determine chemoresistance trends in patients. STAT3 inhibitor treatment, RNAi or ectopic overexpression of STAT3 or MUC1 in NSCLC cells were used to determine their inter-molecular relation and for modulating stemness-related genes.Results: A major subset of chemoresistance patients exhibited a combined aberration of both STAT3 and MUC1 and exhibited a significantly reduced median overall survival (p = 0.008). Subsequent in vitro experiments in NSCLC cells showed that STAT3 levels modulate MUC1 expression (p < 0.01) and increase stemness gene expressions such as AKT (3-fold), OCT4 (4-fold), SOX2 (2-fold) and CXCR4 levels (2 -fold). In addition, co-treatment of STAT3 inhibitor with cisplatin or vinblastine enhanced drug efficiency in viability and invasion assays (p < 0.01) and in a xenograft mouse model (p < 0.05).Conclusion: STAT3 inhibitor co-treatment with chemotherapy drugs increases drug efficacy and reduced tumor growth, and therefore, may improve outcomes in patients on NSCLC chemotherapies.Keywords: STAT3, Non-small cell lung carcinoma, Mucin 1, Chemoresistance, Chemotherap

Synonymous codon usage bias is correlative to intron number and shows disequilibrium among exons in plants

Background: Evidence has been assembled to suggest synonymous codon usage bias (SCUB) has close relationship with intron. However, the relationship (if any) between SCUB and intron number as well as exon position is at present rather unclear. Results: To explore this relationship, the sequences of a set of genes containing between zero and nine introns was extracted from the published genome sequences of three algal species, one moss, one fern and six angiosperms (three monocotyledonous species and three dicotyledonous species). In the algal genomes, the frequency of synonymous codons of the form NNG/NNC (codons with G and C at the third position) was positively related to intron number, but that of NNA/NNT was inversely correlated; the opposite was the case in the land plant genomes. The frequency of NNC/NNG was higher and that of NNA/NNT lower in two terminal exons than in the interstitial exons in the land plant genes, but the rule showed to be opposite in the algal genes. SCUB patterns in the interstitial and two terminal exons mirror the different evolutionary relationships between these plant species, while the first exon shows the highest level of conservation is therefore concluded to be the one which experiences the heaviest selection pressure. The phenomenon of SCUB may also be related to DNA methylation induced conversion of CG to AT. Conclusions: These data provide some evidence of linkage between SCUB, the evolution of introns and DNA methylation, which brings about a new perspective for understanding how genomic variation is created during plant evolution

Generation of novel high quality HMW-GS genes in two introgression lines of Triticum aestivum/Agropyron elongatum

<p>Abstract</p> <p>Background</p> <p>High molecular weight glutenin subunits (HMW-GS) have been proved to be mostly correlated with the processing quality of common wheat (<it>Triticum aestivum</it>). But wheat cultivars have limited number of high quality HMW-GS. However, novel HMW-GS were found to be present in many wheat asymmetric somatic hybrid introgression lines of common wheat/<it>Agropyron elongatum</it>.</p> <p>Results</p> <p>To exploit how these new subunits were generated, we isolated HMW-GS genes from two sib hybrid lines (II-12 and 11-4-6) and compared them with those from their parents. The result shows that two genes of hybrid (<it>H11-3-3 </it>and <it>H11-4-3</it>) are directly introgressed from the donor parent <it>Agropyron elongatum</it>; one hybrid gene (<it>H1Dx5</it>) comes from point mutation of a parental wheat gene (<it>1Dx2.1</it>); two other hybrid genes (<it>H1By8 </it>and <it>H1By16</it>) are likely resulting from unequal crossover or slippage of a parental wheat gene (<it>1By9.1</it>); and the sixth novel hybrid gene (<it>H1Dy12</it>) may come from recombination between two parental genes.</p> <p>Conclusion</p> <p>Therefore, we demonstrate that novel HMW-GS genes can be rapidly created through asymmetric somatic hybridization in a manner similar with the evolution mechanism of these genes supposed before. We also described gene shuffling as a new mechanism of novel HMW-GS gene formation in hybrids. The results suggest that asymmetric somatic hybridization is an important approach for widening HMW-GS genebank of wheat quality improvement.</p

Asymmetric Somatic Hybridization Affects Synonymous Codon Usage Bias in Wheat

Asymmetric somatic hybridization is an efficient strategy for crop breeding by introducing exogenous chromatin fragments, which leads to whole genomic shock and local chromosomal shock that induces genome-wide genetic variation including indel (insertion and deletion) and nucleotide substitution. Nucleotide substitution causes synonymous codon usage bias (SCUB), an indicator of genomic mutation and natural selection. However, how asymmetric somatic hybridization affects SCUB has not been addressed. Here, we explored this issue by comparing expressed sequence tags of a common wheat cultivar and its asymmetric somatic hybrid line. Asymmetric somatic hybridization affected SCUB and promoted the bias to A- and T-ending synonymous codon (SCs). SCUB frequencies in chromosomes introgressed with exogenous fragments were comparable to those in chromosomes without exogenous fragments, showing that exogenous fragments had no local chromosomal effect. Asymmetric somatic hybridization affected SCUB frequencies in indel-flanking sequences more strongly than in non-flanking sequences, and this stronger effect was present in both chromosomes with and without exogenous fragments. DNA methylation-driven SCUB shift was more pronounced than other SC pairs. SCUB shift was similar among seven groups of allelic chromosomes as well as three sub-genomes. Our work demonstrates that the SCUB shift induced by asymmetric somatic hybridization is attributed to the whole genomic shock, and DNA methylation is a putative force of SCUB shift during asymmetric somatic hybridization. Asymmetric somatic hybridization provides an available method for deepening the nature of SCUB shift and genetic variation induced by genomic shock

Genome‑wide association analyses of leaf rust resistance in cultivated emmer wheat

Leaf rust, caused by Puccinia triticina (Pt), constantly threatens durum (Triticum turgidum ssp. durum) and bread wheat (Triticum aestivum) production worldwide. A Pt race BBBQD detected in California in 2009 poses a potential threat to durum production in North America because resistance source to this race is rare in durum germplasm. To find new resistance sources, we assessed a panel of 180 cultivated emmer wheat (Triticum turgidum ssp. dicoccum) accessions for seedling resistance to BBBQD and for adult resistance to a mixture of durum-specific races BBBQJ, CCMSS, and MCDSS in the field, and genotyped the panel using genotype-by-sequencing (GBS) and the 9 K SNP (Single Nucleotide Polymorphism) Infinium array. The results showed 24 and nine accessions consistently exhibited seedling and adult resistance, respectively, with two accessions providing resistance at both stages. We performed genome-wide association studies using 46,383 GBS and 4,331 9 K SNP markers and identified 15 quantitative trait loci (QTL) for seedling resistance located mostly on chromosomes 2B and 6B, and 11 QTL for adult resistance on 2B, 3B and 6A. Of these QTL, one might be associated with leaf rust resistance (Lr) gene Lr53, and two with the QTL previously reported in durum or hexaploid wheat. The remaining QTL are potentially associated with new Lr genes. Further linkage analysis and gene cloning are necessary to identify the causal genes underlying these QTL. The emmer accessions with high levels of resistance will be useful for developing mapping populations and adapted durum germplasm and varieties with resistance to the durum-specific races

The chromosome content and genotype of two wheat cell lines and of their somatic fusion product with oat

Somatic hybridization seeks to genetically combine phylogenetically distant parents. An effective system has been established in bread wheat (Triticum aestivum L.) involving protoplasts from a non-totipotent cell line adapted to in vitro culture (T1) in combination with totipotent protoplasts harvested from embryogenic calli (T2). Here, we report the karyotype and genotype of T1 and T2. Line T1 carries nine A (A-genome of wheat), seven B (B-genome of wheat) and eight D (D-genome of wheat) genome chromosomes, while T2 cells have 12 A, 10 B and 12 D genome chromosomes. Rates of chromosome aberration in the B- and D-genomes were more than 25%, higher than in the A-genome. DNA deletion rates were 55.6% in T1 and 19.4% in T2, and DNA variation rates were 8.3% in T1 and 13.9% in T2. Rate of DNA elimination was B- > D- > A-genome in both T1 and T2. The same set of cytological and genetic assays was applied to a derivative of the somatic fusion between protoplasts of T1, T2 and oat (Avena sativa L.). The regenerant plants were near euploid with respect to their wheat complement. Six wheat chromosome arms—4AL, 3BS, 4BL, 3DS, 6DL and 7DL—carried small introgressed segments of oat chromatin. A genotypic analysis of the hybrid largely confirmed this cytologically-based diagnosis

Characterizing HMW-GS alleles of decaploid Agropyron elongatum in relation to evolution and wheat breeding

Bread wheat quality is mainly correlated with high molecular weight glutenin subunits (HMW-GS) of endosperm. The number of HMW-GS alleles with good processing quality is limited in bread wheat cultivars, while there are plenty of HMW-GS alleles in wheat-related grasses to exploit. We report here on the cloning and characterization of HMW-GS alleles from the decaploid Agropyron elongatum. Eleven novel HMW-GS alleles were cloned from the grass. Of them, five are x-type and six y-type glutenin subunit genes. Three alleles Aex4, Aey7, and Aey9 showed high similarity with another three alleles from the diploid Lophopyrum elongatum, which provided direct evidence for the Ee genome origination of A. elongatum. It was noted that C-terminal regions of three alleles of the y-type genes Aey8, Aey9, and Aey10 showed more similarity with x-type genes than with other y-type genes. This demonstrates that there is a kind of intermediate state that appeared in the divergence between x- and y-type genes in the HMW-GS evolution. One x-type subunit, Aex4, with an additional cysteine residue, was speculated to be correlated with the good processing quality of wheat introgression lines. Aey4 was deduced to be a chimeric gene from the recombination between another two genes. How the HMW-GS genes of A. elongatum may contribute to the improvement of wheat processing quality are discussed

The role of TaCHP in salt stress responsive pathways

In our previous study, we found wheat TaCHP confers salt tolerance through regulating salt responsive signaling pathways. TaCHP possesses three divergent C1 domains that can specifically bind to phospholipid signaling molecule diacylglycerol (DAG) in animal cells, and most of proteins with this domain have kinase activity. Here, we found that TaCHP localizes both at cytoplasmatic membrane and in nuclei; it has no kinase activity but transcriptional activation activity, and the latter owes to C-terminal two C1 domains. TaCHP transcription was reduced by H2O2 application, but its ectopic expression in Arabidopsis improved both ROS production and scavenging capacity, and enhanced tolerance to H2O2 application. We suggest that TaCHP serve as both a transcription factor and a putative DAG binding protein to confer salt tolerance in part through improving ROS scavenging capacity, and that it is a component of the cross-talk machinery in the phospholipids–ROS–salt responsive signaling pathways