Maize kernel oil is a valuable source of nutrition. Here we extensively examine the genetic architecture of maize oil biosynthesis in a genome-wide association study using 1.03 million SNPs characterized in 368 maize inbred lines, including 'high-oil' lines. We identified 74 loci significantly associated with kernel oil concentration and fatty acid composition (P < 1.8 × 10(-6)), which we subsequently examined using expression quantitative trait loci (QTL) mapping, linkage mapping and coexpression analysis. More than half of the identified loci localized in mapped QTL intervals, and one-third of the candidate genes were annotated as enzymes in the oil metabolic pathway. The 26 loci associated with oil concentration could explain up to 83% of the phenotypic variation using a simple additive model. Our results provide insights into the genetic basis of oil biosynthesis in maize kernels and may facilitate marker-based breeding for oil quantity and quality.

Both our previous study and other reports have suggested that CD133, originally classified as a hematopoietic stem cell marker, could be used for enrichment of cancer stem cells (CSCs) in human hepatocellular carcinoma (HCC). It was also noted that not all of CD133 1 cells were representative of CSCs. Further identification and characterization of CSCs or tumor-initiating cells in HCC are necessary to better understand hepatocarcinogenesis. In present study, we demonstrated that CSC phenotype could be precisely defined by co-expression of CD133 and CD44 cell surface markers. CD133 1 CD44 1 HCC cells showed stem cell properties, including extensive proliferation, self-renewal, and differentiation into the bulk of cancer cells. In vivo xenograft experiments revealed that, actually, the highly tumorigenic capacity of CD133 1 cells as previously described was primarily attributed to CD133 1 CD44 1 cell subpopulation, instead of their CD133 1 CD44 2 counterparts. Moreover, cells double-positive for CD133 and CD44 exhibited preferential expression of some stem cell-associated genes and were more resistant to chemotherapeutic agents due to the upregulation of ATP-binding cassette (ABC) superfamily transporters, including ABCB1, ABCC1, and ABCG2, further supporting these cells as HCC cell origin. Our findings suggest that CD133 1 CD44 1 cells might represent true cancer stem/progenitor cells in HCC, which could allow a better understanding of HCC initiation and progression, as well as establish a precise target for the development of more effective therapies.

Coronary artery disease (CAD) causes more than 700,000 deaths each year in China. Previous genome-wide association studies (GWAS) in populations of European ancestry identified several genetic loci for CAD, but no such study has yet been reported in the Chinese population. Here we report a three-stage GWAS in the Chinese Han population. We identified a new association between rs6903956 in a putative gene denoted as C6orf105 on chromosome 6p24.1 and CAD (P = 5.00 × 10⁻³, stage 2 validation; P = 3.00 × 10⁻³, P = 1.19 × 10⁻⁸ and P = 4.00 × 10⁻³ in three independent stage 3 replication populations; P = 4.87 × 10⁻¹², odds ratio = 1.51 in the combined population). The minor risk allele A of rs6903956 is associated with decreased C6orf105 mRNA expression. We report the first GWAS for CAD in the Chinese Han population and identify a SNP, rs6903956, in C6orf105 associated with susceptibility to CAD in this population.

Active drug efflux by the adenosine triphosphate-binding cassette (ABC) transporter ABCG2 is one of the common mechanisms causing multiple drug resistance in various human cancers. In the intrinsic drug resistance of hepatocellular carcinoma (HCC), the role of ABCG2 is closely associated with 'side population (SP)', a minor subset of cancer stem-like cells with unique capacity to extrude lipophilic dye Hoechst 33342 and many chemotherapeutic agents. In this study, we showed that ABCG2 was intrinsically expressed in a subgroup of HCC tissues and its expression pattern significantly influenced the levels of drug efflux from HCC cell lines. In MHCC-97L HCC cell line with intrinsic ABCG2 expression, we confirmed the importance of SP cells to the drug efflux-related chemotherapy resistance and found that the SP analysis provided an efficient method to evaluate the functional activity of ABCG2 transporter. In this cell line, we discovered that the SP proportion was modulated by the treatments of Akt signaling inhibitors and serum supplement, which led to the finding that Akt signaling was able to regulate the SP cells' efflux activity via altering the subcellular localization of ABCG2 transporter. We further demonstrated that the Akt signaling inhibition attenuated the doxorubicin efflux from MHCC-97L cells and increased the drug efficacy. Our results indicate the protective role of intrinsic ABCG2 expression in HCC cells and suggest that suppressing Akt signaling could help overcome the drug efflux by ABCG2 transporter.