Construction, expression and purification of a mammalian secretory recombinant fusion protein rPC / 生物工程学报

Drugs targeting immune checkpoint are used for cancer treatment, but resistance to single drug may occur. Combination therapy blocking multiple checkpoints simultaneously can improve clinical outcome. Therefore, we designed a recombinant protein rPC to block multiple targets, which consists of extracellular domains of programmed cell death protein 1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4). The coding sequence was inserted into expression vector and stably transfected into HEK293 cells. The culture supernatant was collected and rPC was affinity-purified. Real-time quantitative PCR was used to evaluate the expression levels of ligands for PD-1 and CTLA-4 in several human cancer cell lines. The binding of rPC with cancer cells was examined by immunofluorescence cell staining, the influence of rPC on cancer cell growth was assayed by CCK-8. The results showed that rPC could be expressed and secreted by stably transfected HEK293 cells, the purified rPC could bind to lung cancer NCI-H226 cells which have high levels of ligands for PD-1 and CTLA-4, no direct impact on cancer cell growth could be observed by rPC treatment. The recombinant protein rPC can be functionally assayed further for developing novel immunotherapeutic drugs for cancer.

Advances in nucleotide reductase inhibitors for antiviral therapy / 中华临床感染病杂志

Ribonucleotide reductase ( RR ) is a rate-limiting enzyme, and it is responsible for reducing ribonucleotides to their corresponding deoxyribonucleotides , which are the building blocks required for DNA replication and repair .Recent studies have revealed that RR activity is associated with DNA replication in virus , and RR inhibitors have been used for clinical antiviral treatment .This paper reviews research progress on RR and its inhibitors , including the classification , structure and function of RR; the classification, mechanism and clinical application of RR inhibitors in antiviral therapy and the future prospects of RR inhibitors .