Inducible caspase-9 suicide gene under control of endogenous oct4 to safeguard mouse and human pluripotent stem cell therapy

Pluripotent stem cells (PSCs) are promising in regenerative medicine. A major challenge of PSC therapy is the risk of teratoma formation because of the contamination of undifferentiated stem cells. Constitutive promoters or endogenous SOX2 promoters have been used to drive inducible caspase-9 (iCasp9) gene expression but cannot specifically eradicate undifferentiated PSCs. Here, we inserted iCasp9 gene into the endogenous OCT4 locus of human and mouse PSCs without affecting their pluripotency. A chemical inducer of dimerization (CID), AP1903, induced iCasp9 activation, which led to the apoptosis of specific undifferentiated PSCs in vitro and in vivo. Differentiated cell lineages survived because of the silence of the endogenous OCT4 gene. Human and mouse PSCs were controllable when CID was administrated within 2 weeks after PSC injection in immunodeficient mice. However, an interval longer than 2 weeks caused teratoma formation and mouse death because a mass of somatic cells already differentiated from the PSCs. In conclusion, we have developed a specific and efficient PSC suicide system that will be of value in the clinical applications of PSC-based therapy.

Hsa-miR-3658 down-regulates OCT4 gene expression followed by suppressing SW480 cell proliferation and migration

The pluripotency factor, OCT4 gene is a stemness marker that is involved in the tumorigenicity of different cancer types and knowing about molecular mechanisms of its regulation is crucially important. To date, a few microRNAs (miRNAs) are known to be regulators of OCT4 gene expression. Looking for the novel miRNAs which are capable of regulating OCT4 gene expression, our bioinformatics analysis introduced hsa-miR-3658 (miR-3658) as a bona fide candidate. Then, RT-qPCR results indicated that miR-3658 expression is decreased in colorectal cancer (CRC) tumor tissues, compared with normal pairs. Furthermore, RT-qPCR and western blot analysis showed that the OCT4 gene has been down-regulated following the miR-3658 overexpression. Consistently, dual-luciferase assay supported the direct interaction of miR-3658 with the 3'-UTR sequence of OCT4 gene. Unlike in HCT116 cells, overexpression of miR-3658 in SW480 cells brought about growth inhibition, cell cycle arrest and reduced cell migration, detected by flow cytometry, and scratch test assay. Overall, these findings demonstrated that miR-3658 as a tumor suppressor miRNA exerts its effect against OCT4 gene expression, and it has the potential of being used as a prognostic marker and therapeutic target against colorectal cancer.

Efficient One-Step Knockout by Electroporation of Ribonucleoproteins Into Zona-Intact Bovine Embryos

Somatic cell nuclear transfer or cytoplasm microinjection have been used to generate genome-edited farm animals; however, these methods have several drawbacks that reduce their efficiency. This study aimed to develop electroporation conditions that allow delivery of CRISPR/Cas9 system to bovine zygotes for efficient gene knock-out. We optimized electroporation conditions to deliver Cas9:sgRNA ribonucleoproteins to bovine zygotes without compromising embryo development. Higher electroporation pulse voltage resulted in increased membrane permeability; however, voltages above 15 V/mm decreased embryo developmental potential. The zona pellucida of bovine embryos was not a barrier to efficient RNP electroporation. Using parameters optimized for maximal membrane permeability while maintaining developmental competence we achieved high rates of gene editing when targeting bovine OCT4, which resulted in absence of OCT4 protein in 100% of the evaluated embryos and the expected arrest of embryonic development at the morula stage. In conclusion, Cas9:sgRNA ribonucleoproteins can be delivered efficiently by electroporation to zona-intact bovine zygotes, resulting in efficient gene knockouts.

Different Genotype of rs3130932 Single Nucleotide Polymorphism Between Gastric Cancer Patients and Normal Subjects

PURPOSE

Octamer binding transcription factor B gene (OCT4) is responsible for development and self-renewal maintenance of embryonic stem cells. The rs3130932 single nucleotide polymorphism (SNP) may play a role in tumor genesis. Because of high prevalence of gastric cancer in north of Iran, this study was investigated role of rs3130932 polymorphism and stomach cancer.

METHODS

Blood samples were collected from 100 informed gastric cancer patients and 100 age and sex-matched healthy individuals, and were genotyped for the presence of rs3130932G allele by ssp PCR.

RESULTS

The mean age of participant (n = 200) was 67.83 ± 10.878 years. In genotyping and allelic analysis, TG genotype increased 66.147 times more likely to develop stomach cancer than the TT genotype, and disease risk increases 140.496 times more in GG genotype in comparison with TT genotype.

CONCLUSION

This study clearly emphasis on different genetic profile in this population and show that the rs3130932G allele and odds of gastric cancer are related to each other in northern of Iran.