Discovering and Characterizing of Survivin Dominant Negative Mutants With Stronger Pro-apoptotic Activity on Cancer Cells and CSCs.

Survivin as a member of the inhibitor of apoptosis proteins (IAPs) family is undetectable in normal cells, but highly expressed in cancer cells and cancer stem cells (CSCs) which makes it an attractive target in cancer therapy. Survivin dominant negative mutants have been reported as competitive inhibitors of endogenous survivin protein in cancer cells. However, there is a lack of systematic comparative studies on which mutants have stronger effect on promoting apoptosis in cancer cells, which will hinder the development of novel anti-cancer drugs. Here, based on the previous study of survivin and its analysis of the relationship between structure and function, we designed and constructed a series of different amino acid mutants from survivin (TmSm34, TmSm48, TmSm84, TmSm34/48, TmSm34/84, and TmSm34/48/84) fused cell-permeable peptide TATm at the N-terminus, and a dominant negative mutant TmSm34/84 with stronger pro-apoptotic activity was selected and evaluated systematically in vitro. The double-site mutant of survivin (TmSm34/84) showed more robust pro-apoptotic activity against A549 cells than others, and could reverse the resistance of A549 CSCs to adriamycin (ADM) (reversal index up to 7.01) by decreasing the expression levels of survivin, P-gp, and Bcl-2 while increasing cleaved caspase-3 in CSCs. This study indicated the selected survivin dominant negative mutant TmSm34/84 is promising to be an excellent candidate for recombinant anti-cancer protein by promoting apoptosis of cancer cells and their stem cells and sensitizing chemotherapeutic drugs.

Designing and constructing a phage display synthesized single domain antibodies library based on camel VHHs frame for screening and identifying humanized TNF-α-specific nanobody.

Tumor necrosis factor (TNF-α) is an important clinically tested cytokine that could induce autoimmune diseases and inflammation. Therefore, the anti-TNF-α therapy strategy was developed and used therapeutically in various diseases, especially in the cytokine storm associated chimeric antigen receptor (CAR) T-cell therapy and antiviral therapy. Compare with other anti-TNF-α inhibitors, anti-TNF-α Nb (nanobody) has many unique advantages. Herein, we reported a novel humanized scaffold for library construction, which could be soluble and expressed in Escherichia coli (E.coli), and the efficiency capacity could reach as high as 2.01 × 109. Meanwhile, an anti-TNF-α Nb was selected for further study after 4 rounds of screening, NT-3, as the optimal Nb could effectively inhibit TNF-mediated cytotoxicity. The IC50 of NT-3 was determined as 0.804 µM, and its apoptosis inhibition rate was 62.47 % in L929 cells. Furthermore, the molecular docking results showed that complementarity-determining regions (CDRs) of NT-3 could connect to TNF for blocking function through strong hydrogen bonds and salt bridges. In general, our study not only provided a good Nb screening platform in vitro without animal immunization, but also generated a series of novel humanized anti-TNF-α Nb candidates with potential applications.

A novel liposome-polymer hybrid nanoparticles delivering a multi-epitope self-replication DNA vaccine and its preliminary immune evaluation in experimental animals.

DNA vaccine is an attractive immune platform for the prevention and treatment of infectious diseases, but existing disadvantages limit its use in preclinical and clinical assays, such as weak immunogenicity and short half-life. Here, we reported a novel liposome-polymer hybrid nanoparticles (pSFV-MEG/LNPs) consisting of a biodegradable core (mPEG-PLGA) and a hydrophilic shell (lecithin/PEG-DSPE-Mal 2000) for delivering a multi-epitope self-replication DNA vaccine (pSFV-MEG). The pSFV-MEG/LNPs with optimal particle size (161.61 ±â€¯15.63 nm) and high encapsulation efficiency (87.60 ±â€¯8.73%) induced a strong humoral (3.22-fold) and cellular immune responses (1.60-fold) compared to PBS. Besides, the humoral and cellular immune responses of pSFV-MEG/LNPs were 1.58- and 1.05-fold than that of pSFV-MEG. All results confirmed that LNPs was a very promising tool to enhance the humoral and cellular immune responses of pSFV-MEG. In addition, the rational design and delivery platform can be used for the development of DNA vaccines for other infectious diseases.

Multiple targeting strategies achieve novel protein drug delivery into proapoptosis lung cancer cells by precisely inhibiting survivin.

Therapeutic recombinant proteins have numerous advantages and benefits over chemical drugs, particularly high specificity and good biocompatibility. However, the therapeutic potential and clinical application of current anticancer protein drugs are limited as most biomarkers are located within cells, and multiple physiological barriers exist between the point of administration and the intracellular biomarker. Herein, we report a novel strategy to accurately deliver a cell-permeable dominant-negative TATm-Survivin (TmSm) protein (T34A) to intracellular survivin in cancer cells by overcoming multiple barriers in vivo. A poly(d,l-lactide-co-glycolide) (PLGA) inner core, a polyethylene glycol (PEG) modification, and a TATm peptide were simultaneously introduced to mediate tumor tissue targeting and response to pH-triggered TmSm release. Compared to free TmSm, the PEGylated-PLGA nanoparticle platform achieved a significantly higher cellular uptake efficiency (1.79-fold for A549 and 1.77-fold for Capan-2), effectively decreased IC50 (1.22-fold for A549 and 1.17-fold for Capan-2), and largely elevated apoptosis in different cancer cells (1.17-fold for A549 and 1.15-fold for Capan-2). Besides, this newly developed nanoplatform showed increased protein drug accumulation in the tumor site in A549-bearing nude mice and reached a tumor inhibition rate of 55.81% (1.35-fold versus free TmSm) by reducing the expression of intracellular survivin. All these results confirmed that our newly developed delivery strategy is a very promising tool, which helps protein drugs to cross multiple barriers in vivo and achieves precise targeting to intracellular biomarkers. This strategy could also be applied to other types of protein drugs to further improve their clinical anticancer therapeutic efficacy.