Exogenous c-Myc Blocks Differentiation and Improves Expansion of Human Erythroblasts In vitro

Efficient synthesis of 2'-O-methoxyethyl oligonucleotide - cationic peptide conjugates

Single-stranded phosphorothioate (PS) oligonucleotide drugs have shown potential for the treatment of several rare diseases. However, a barrier to their widespread use is that they exhibit activity in only a narrow range of tissues. One way to circumvent this constraint is to conjugate them to cationic cell-penetrating peptides (CPPs). Although there are several examples of morpholino and peptide nucleic acids conjugated with CPPs, there are noticeably few examples of PS oligonucleotide-CPP conjugates. This is surprising given that PS oligonucleotides presently represent the largest class of approved RNA-based drugs, including Nusinersen, that bears the 2'- O -methoxyethyl (MOE) chemistry. In this work, we report a method for in-solution conjugation of cationic, hydrophobic peptides or human serum albumin to a 22-nucleotide MOE-PS oligonucleotide. Conjugates were obtained in high yields and purities. Our findings pave the way for their large-scale synthesis and testing in vivo .

Curcumin suppresses the proliferation of gastric cancer cells by downregulating H19

Curcumin, a major phytochemical in turmeric, inhibits the proliferation of many types of solid cancer cells by enhancing p53 expression. However, the long non-coding RNA H19 directly inhibits p53 activation and thus promotes gastric cancer progression. The aim of this study was to assess the role of H19 in curcumin-induced proliferative inhibition of gastric cancer. The gastric cancer cell line SGC-7901 was treated with curcumin at different concentrations and time points. The effect of curcumin on proliferation was assessed using cell counting kit-8 assays and flow cytometry with Ki67 staining. In addition, H19 expression was quantified by reverse transcription-quantitative polymerase chain reaction, and apoptosis was evaluated by flow cytometric detection of Annexin V and propidium iodide double staining. The protein expression of p53, B-cell lymphoma (Bcl)-2, Bcl-2-associated X protein (Bax) and c-Myc in curcumin-treated cells was detected by western blotting. The present study demonstrated that curcumin inhibited the proliferation of SGC7901 cells and suppressed H19 expression in a concentration-dependent manner, while p53 expression was enhanced. Ectopic expression of H19 in SGC7901 cells reversed curcumin-induced proliferative inhibition and downregulated p53 expression. Furthermore, while curcumin induced cell apoptosis and enhanced the expression ratio of Bax/Bcl-2, which are downstream molecules of p53, ectopic expression of H19 inhibited curcumin-induced cell apoptosis. In addition, curcumin decreased the expression of the c-Myc oncogene, and exogenous c-Myc protein reversed the curcumin-induced downregulation of H19 expression. These results suggested that curcumin inhibits the proliferation of gastric cancer cells by downregulating the c-Myc/H19 pathway. Therefore, curcumin may be considered a novel therapeutic strategy to inhibit gastric cancer cell growth.

Genetically Engineered In Vitro Erythropoiesis

Background

Engineered blood has the greatest potential to combat a predicted future shortfall in the US blood supply for transfusion treatments. Engineered blood produced from hematopoietic stem cell (HSC) derived red blood cells in a laboratory is possible, but critical barriers exist to the production of clinically relevant quantities of red blood cells required to create a unit of blood. Erythroblasts have a finite expansion capacity and there are many negative regulatory mechanisms that inhibit in vitro erythropoiesis. In order to overcome these barriers and enable mass production, the expansion capacity of erythroblasts in culture will need to be exponentially improved over the current state of art. This work focused on the hypothesis that genetic engineering of HSC derived erythroblasts can overcome these obstacles.

Objectives

The objective of this research effort was to improve in vitro erythropoiesis efficiency from human adult stem cell derived erythroblasts utilizing genetic engineering. The ultimate goal is to enable the mass production of engineered blood.

Methods

HSCs were isolated from blood samples and cultured in a liquid media containing growth factors. Cells were transfected using a Piggybac plasmid transposon.

Results

Cells transfected with SPI-1 continued to proliferate in a liquid culture media. Fluorescence-activated cell sorting (FACS) analysis on culture day 45 revealed a single population of CD71⁺CD117⁺ proerythroblast cells. The results of this study suggest that genetically modified erythroblasts could be immortalized in vitro by way of a system modeling murine erythroleukemia.

Conclusion

Genetic modification can increase erythroblast expansion capacity and potentially enable mass production of red blood cells.

Partial Loss of Rpl11 in Adult Mice Recapitulates Diamond-Blackfan Anemia and Promotes Lymphomagenesis

Diamond-Blackfan anemia (DBA) is characterized by anemia and cancer susceptibility and is caused by mutations in ribosomal genes, including RPL11. Here, we report that Rpl11-heterozygous mouse embryos are not viable and that Rpl11 homozygous deletion in adult mice results in death within a few weeks, accompanied by bone marrow aplasia and intestinal atrophy. Importantly, Rpl11 heterozygous deletion in adult mice results in anemia associated with decreased erythroid progenitors and defective erythroid maturation. These defects are also present in mice transplanted with inducible heterozygous Rpl11 bone marrow and, therefore, are intrinsic to the hematopoietic system. Additionally, heterozygous Rpl11 mice present increased susceptibility to radiation-induced lymphomagenesis. In this regard, total or partial deletion of Rpl11 compromises p53 activation upon ribosomal stress or DNA damage in fibroblasts. Moreover, fibroblasts and hematopoietic tissues from heterozygous Rpl11 mice present higher basal cMYC levels. We conclude that Rpl11-deficient mice recapitulate DBA disorder, including cancer predisposition.