Targeting Telomere Dynamics as an Effective Approach for the Development of Cancer Therapeutics.

Telomere is a protective structure located at the end of chromosomes of eukaryotes, involved in maintaining the integrity and stability of the genome. Telomeres play an essential role in cancer progression; accordingly, targeting telomere dynamics emerges as an effective approach for the development of cancer therapeutics. Targeting telomere dynamics may work through multifaceted molecular mechanisms; those include the activation of anti-telomerase immune responses, shortening of telomere lengths, induction of telomere dysfunction and constitution of telomerase-responsive drug release systems. In this review, we summarize a wide variety of telomere dynamics-targeted agents in preclinical studies and clinical trials, and reveal their promising therapeutic potential in cancer therapy. As shown, telomere dynamics-active agents are effective as anti-cancer chemotherapeutics and immunotherapeutics. Notably, these agents may display efficacy against cancer stem cells, reducing cancer stem levels. Furthermore, these agents can be integrated with the capability of tumor-specific drug delivery by the constitution of related nanoparticles, antibody drug conjugates and HSA-based drugs.

Antitumor efficacy of a recombinant EGFR-targeted fusion protein conjugate that induces telomere shortening and telomerase downregulation.

OBJECTIVE: To prepare a recombinant EGFR-targeted fusion protein drug conjugate acting on telomere and telomerase; and evaluate its antitumor efficacy. METHODS: We prepared a recombinant fusion protein Fv-LDP-D3 which consists of the Fv fragment of an anti-EGFR monoclonal antibody (MAb), the apoprotein of lidamycin (LDP), and the third domain (D3) of human serum albumin (HSA); then generated the conjugate Fv-LDP-D3∼AE by integrating the active enediyne chomophore (AE) of lidamycin. Accordingly, in vitro and in vivo experiments were performed. RESULTS: As shown, Fv-LDP-D3 specifically bound to EGFR highly-expressing cancer cells and intensely entered K-Ras mutant cells via enhanced macropinocytosis. By in vivo imaging, Fv-LDP-D3 displayed intense accumulation and persistent retention in tumor-site. Furthermore, the conjugate Fv-LDP-D3∼AE displayed highly potent cytotoxicity to cancer cells with IC50 at 0.1 nM level. The conjugate induced telomere shortening and downregulation of telomerase and EGFR pathway related proteins. Fv-LDP-D3∼AE exhibited prominent antitumor efficacy against human colorectal cancer xenograft accompanying with significant increase of serum IFN-ß in athymic mice. CONCLUSION: The recombinant fusion protein conjugate that exhibits the capability of tumor-targeting drug delivery can induce telomere shortening and telomerase downregulation. The investigation may lay the foundation for the development of MAb-HSA domain-based fusion protein drug conjugates.

The recombinant defensin/HSA fusion protein that inhibits NF-κb associated with intensive macropinocytosis shows potent efficacy against pancreatic cancer.

KRAS mutation and NF-κB both play crucial role in pancreatic cancer; in addition, defensin, the peptide mediator in innate immunity, can inhibit NF-κB. Assuming a strategy that targets both NF-κB and concomitantly the mutated KRAS indirectly via intensive macropinocytosis, we designed and generated a recombinant protein DF2-HSA which consists of two molecules of human beta-defensin 2 (HBD2) and a moiety of human serum albumin (HSA). As shown, the recombinant protein DF2-HSA markedly down-regulated NF-κB in both KRAS mutant MIA PaCa-2 cells and wild type BxPC-3 cells. Determined by confocal microscopy, the uptake of DF2-HSA in MIA PaCa-2 cells was more intense than that in BxPC-3 cells. The uptake was blocked by the specific inhibitor EIPA, indicating that DF2-HSA internalized via macropinocytosis. DF2-HSA displayed more potent cytotoxicity to cancer cells than HBD2. DF2-HSA induced apoptosis in cancer cells. Notably, DF2-HSA inhibited tumor cell spheroid formation, an effect comparable to that of salinomycin. DF2-HSA inhibited tumor cell migration and invasion. As detected with scanning electron microscopy, DF2-HSA strongly depleted filopodia on cell surface; and salinomycin induced similar changes. By in vivo imaging, DF2-HSA displayed intense tumor-site accumulation and lasting retention for over 14 days; however, HBD2 showed much less tumor-site accumulation and a shorter retention time for only 24 h. DF2-HSA suppressed the growth of pancreatic cancer MIA PaCa-2 xenograft in athymic mice; and its combination with gemcitabine achieved higher antitumor efficacy. In summary, the recombinant defensin/HSA fusion protein that inhibits NF-κb associated with intensive macropinocytosis is highly effective against pancreatic cancer.

The development of human serum albumin-based drugs and relevant fusion proteins for cancer therapy.

Human serum albumin (HSA)-based therapeutics have attracted tremendous attention in the development of anticancer agents. The versatile properties of HSA make HSA-based therapeutics possess improved pharmacokinetics, extended circulation half-life, enhanced efficacy, reduced toxicity, etc. Generally, the HSA-based therapeutics systems can be divided into four categories, i.e. HSA-drug nanoparticles, HSA-drug conjugates, HSA-binding prodrugs, and HSA-based recombinant fusion proteins: the latter mainly include antibody (domain)- and cytokine- fusion proteins. Advances in this area revealed the advantages of HSA-based systems in the development of tumor site-oriented therapeutics, partly referring to the enhanced penetration and retention (EPR) effect and the intensive macropinocytosis. Accordingly, a variety of technical platforms for the design and preparation of HSA-based therapeutics have been reported. Major strategies and directions for the drug development were discussed; those include (1) Tumor-site oriented drug delivery and enhanced drug retention, (2) Tumor-site prodrug release and activation, (3) Cancer cell bound intensive drug internalization, and (4) Tumor microenvironment (TME) directed immunomodulation. Notably, the multimodal HSA-based approach is promising for the development of tumor-oriented therapeutics for cancer therapy.

The ionophore antibiotic gramicidin A inhibits pancreatic cancer stem cells associated with CD47 down-regulation.

BACKGROUND: Pancreatic cancer stem cells (CSCs), a special population of cells, renew themselves infinitely and resist to various treatment. Gramicidin A (GrA), an ionophore antibiotic derived from microorganism, can form channels across the cell membrane and disrupt cellular ionic homeostasis, leading to cell dysfunction and death. As reported, the ionophore antibiotic salinomycin (Sal) has been proved to kill CSCs effectively. Whether GrA owns the potential as a therapeutic drug for CSCs still remains unknown. This study investigated the effect of GrA on pancreatic CSCs and the mechanism. METHODS: Tumorsphere formation assay was performed to assess pancreatic CSCs self-renewal potential. In vitro hemolysis assay was determined to test the borderline concentration of GrA. CCK-8 assay was used to detect pancreatic cancer cell proliferation capability. Flow cytometry was performed to detect cell apoptosis and mitochondrial membrane potential. Scanning and transmission electron microscopy was used to observe ultrastructural morphological changes on cell membrane surface and mitochondria, respectively. Western blot analysis was used to determine relative protein expression levels. Immunofluorescence staining was performed to observe CD47 re-distribution. RESULTS: GrA at 0.05 µM caused tumorspheres disintegration and decrease in number of pancreatic cancer BxPC-3 and MIA PaCa-2 cells. GrA and Sal both inhibited cancer cell proliferation. The IC50 values of GrA and Sal for BxPC-3 cells were 0.025 µM and 0.363 µM; while for MIA PaCa-2 cells were 0.032 µM and 0.163 µM, respectively. Compared on equal concentrations, the efficacy of GrA was stronger than that of Sal. GrA at 0.1 µM or lower did not cause hemolysis. GrA induced ultrastructural changes, such as the decrease of microvilli-like protrusions on cell surface membrane and the swelling of mitochondria. GrA down-regulated the expression levels of CD133, CD44, and CD47; in addition, CD47 re-distribution was observed on cell surface. Moreover, GrA showed synergism with gemcitabine in suppressing cancer cell proliferation. CONCLUSIONS: The study found that GrA was highly active against pancreatic CSCs. It indicates that GrA exerts inhibitory effects against pancreatic CSCs associated with CD47 down-regulation, implying that GrA might play a positive role in modulating the interaction between macrophages and tumor cells.

Specialized Pro-resolving Mediators Regulate Alveolar Fluid Clearance during Acute Respiratory Distress Syndrome / 中华医学杂志(英文版)

<p><b>Objective</b>Acute respiratory distress syndrome (ARDS) is an acute and lethal clinical syndrome that is characterized by the injury of alveolar epithelium, which impairs active fluid transport in the lung, and impedes the reabsorption of edema fluid from the alveolar space. This review aimed to discuss the role of pro-resolving mediators on the regulation of alveolar fluid clearance (AFC) in ARDS.</p><p><b>Data Sources</b>Articles published up to September 2017 were selected from the PubMed, with the keywords of "alveolar fluid clearance" or "lung edema" or "acute lung injury" or "acute respiratory distress syndrome", and "specialized pro-resolving mediators" or "lipoxin" or "resolvin" or "protectin" or "maresin" or "alveolar epithelial cells" or "aspirin-triggered lipid mediators" or "carbon monoxide and heme oxygenase" or "annexin A1".</p><p><b>Study Selection</b>We included all relevant articles published up to September 2017, with no limitation of study design.</p><p><b>Results</b>Specialized pro-resolving mediators (SPMs), as the proinflammatory mediators, not only upregulated epithelial sodium channel, Na,K-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR), and aquaporins levels, but also improved Na,K-ATPase activity to promote AFC in ARDS. In addition to the direct effects on ion channels and pumps of the alveolar epithelium, the SPMs also inhibited the inflammatory cytokine expression and improved the alveolar epithelial cell repair to enhance the AFC in ARDS.</p><p><b>Conclusions</b>The present review discusses a novel mechanism for pulmonary edema fluid reabsorption. SPMs might provide new opportunities to design "reabsorption-targeted" therapies with high degrees of precision in controlling ALI/ARDS.</p>

Analysis of sedative effect of dexmedetomidine combined with remifentanil in patients with mechanical ventilation after ICU surgery / 中国生化药物杂志

Objective investigate the analgesic effect of dexmedetomidine combined with remifentanil in patients with mechanical ventilation after ICU surgery. Methods 120 patients with ICU underwent mechanical ventilation were divided into control group (propofol combined remifentanil) and observation group (dexmedetomidine remifentanil) according to the random number table method, 60 cases each group. Record the two groups of total sedation time, withdrawal time after the withdrawal, analgesic effect, adverse reactions. Results The scores of SAS score and CPOT were (3.98±0.52) and (2.23±1.04), respectively, which were significantly lower than those in the control group (4.36±0.96) and (3.46±2.23), respectively (P<0.05). (691.28±236.58) min and (1.22±0.05) min were significantly shorter than those in the control group (2642.33±341.58) min, (3.56±0.74) min, P<0.05, respectively. The adverse reaction rate was 3.33% (2/60) in the observation group, which was significantly lower than that in the control group (13.33%, 8/60),( χ2=3.92, P=0.04). Conclusion ICU postoperative mechanical ventilation patients with dexmedetomidine combined with remifentanil has a good analgesic effect, and is conducive to the patient wake up, less adverse reactions, with a certain safety.

Analysis of sedative effect of dexmedetomidine combined with remifentanil in patients with mechanical ventilation after ICU surgery / 中国生化药物杂志

Objective investigate the analgesic effect of dexmedetomidine combined with remifentanil in patients with mechanical ventilation after ICU surgery. Methods 120 patients with ICU underwent mechanical ventilation were divided into control group (propofol combined remifentanil) and observation group (dexmedetomidine remifentanil) according to the random number table method, 60 cases each group. Record the two groups of total sedation time, withdrawal time after the withdrawal, analgesic effect, adverse reactions. Results The scores of SAS score and CPOT were (3.98±0.52) and (2.23±1.04), respectively, which were significantly lower than those in the control group (4.36±0.96) and (3.46±2.23), respectively (P<0.05). (691.28±236.58) min and (1.22±0.05) min were significantly shorter than those in the control group (2642.33±341.58) min, (3.56±0.74) min, P<0.05, respectively. The adverse reaction rate was 3.33% (2/60) in the observation group, which was significantly lower than that in the control group (13.33%, 8/60),( χ2=3.92, P=0.04). Conclusion ICU postoperative mechanical ventilation patients with dexmedetomidine combined with remifentanil has a good analgesic effect, and is conducive to the patient wake up, less adverse reactions, with a certain safety.

A recombinantly tailored ß-defensin that displays intensive macropinocytosis-mediated uptake exerting potent efficacy against K-Ras mutant pancreatic cancer.

K-Ras mutant pancreatic cancer cells display intensive macropinocytosis, indicating that this process may be exploited in the design of anticancer targeted therapies. In this study, we constructed a macropinocytosis-oriented recombinantly tailored defensin (DF-HSA) which consists of human ß-defensin-2 (DF) and human serum albumin (HSA). The macropinocytosis intensity and cytotoxicity of DF-HSA were investigated in K-Ras mutant MIA PaCa-2 cells and wild-type BxPC-3 cells. As found, the DF-HSA uptake in MIA PaCa-2 cells was much higher than that in wild-type BxPC-3 cells. Correspondingly, the cytotoxicity of DF-HSA to MIA PaCa-2 cells was more potent than that to BxPC-3 cells. In addition, the cytotoxicity of DF-HSA was much stronger than that of ß-defensin HBD2. DF-HSA suppressed cancer cell proliferation and induced mitochondrial pathway apoptosis. Notably, DF-HSA significantly inhibited the growth of human pancreatic carcinoma MIA PaCa-2 xenograft in athymic mice at well tolerated dose. By in vivo imaging, DF-HSA displayed a prominent accumulation in the tumor. The study indicates that the recombinantly tailored ß-defensin can intensively enter into the K-Ras mutant pancreatic cancer cells through macropinocytosis-mediated process and exert potent therapeutic efficacy against the pancreatic carcinoma xenograft. The novel format of ß-defensin may play an active role in macropinocytosis-mediated targeting therapy.

Alterations of peripheral blood T cell subsets in patients with sepsis and the clinical implications / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the dynamic changes of CD3+, CD4+, and CD8+ T lymphocytes in the peripheral blood of patients with sepsis and discuss the clinical significance.</p><p><b>METHODS</b>Sixty-four patients admitted in the Emergency Center and Emergency Intensive Care Unit of the Second Hospital of Wenzhou Medical University between August, 2007 and July, 2009 were enrolled in this study. CD3+, CD4+, and CD8+ T lymphocytes in the peripheral blood were detected by flow cytometry on days 1, 7 and 14 after admission, and the results were compared between the patients with improvement of the condition and those without improvement, with 20 healthy subjects as the control group.</p><p><b>RESULTS</b>On day 1 after admission, CD3+ and CD4+ T lymphocytes and CD4+/CD8+ T cell ratio were obviously lower in the 2 groups of patients with sepsis than in the control group (P<0.05), but no significant difference was found in CD8+ T lymphocytes. The sepsis patients with clinical improvement showed significant higher CD3+ and CD4+ T lymphocyte percentages and CD4+/CD8+ T cell ratio than those without improvement on day 1. In the patients with clinical improvement, CD3+ and CD4+T lymphocytes and CD4+/CD8+ T cell ratio increased gradually with time and till day 14, they were comparable with the control levels; in the patients without improvement, CD3+ and CD4+ T lymphocytes and CD4+/CD8+ T cell ratio showed no obvious alterations in the course of observation.</p><p><b>CONCLUSION</b>Immune imbalance occurs in patients with sepsis represented by lowered CD3+ and CD4+T lymphocyte percentages and CD4+/CD8+ T cell ratio in relation to the severity of the condition. CD3+ and CD4+ T lymphocytes and CD4+/CD8+ T cell ratio can be used as the indicators for assessing the severity of sepsis.</p>

[Construction and screening of phage antibody libraries against epidermal growth factor receptor and soluble expression of single chain Fv].

Recent studies have shown that epidermal growth factor receptor (EGFR) is an important target for cancer therapy. The present study prepared single chain Fv (scFv) directed against EGFR. Balb/c mice were immunized by human carcinoma A431 cells, and total RNA of the splenic cells was extracted. VH and VL gene fragments were amplified by RT-PCR and further joined into scFv gene with a linker, then scFv gene fragments were ligated into the phagemid vector pCANTAB 5E. The phagemid containing scFv were transformed into electro-competent E. coli TG1 cells. The recombinant phage antibody library was constructed through rescuing the transformed cells with help phage M13K07. The specified recombinant phages were enriched through 5 rounds of affinity panning and the anti-EGFR phage scFv clones were screened and identified with ELISA. A total of 48 clones from the library were selected randomly and 45 clones were identified positive. After infecting E. coli HB2151 cells with one positive clone, soluble recombinant antibodies about 27 kD were produced and located in the periplasm and the supernatant. The result of sequencing showed that the scFv gene was 768 bp, which encoded 256 amino acid residues. VH and VL including 3 CDRs and 4 FRs, respectively, were all homologous to mouse Ig. The soluble scFv showed the specific binding activity to purified EGFR and EGFR located in carcinoma cell membrane. The successful preparation of anti-EGFR scFv will provide an EGFR targeted molecule for the development of antibody-based drugs and biological therapy of cancer.

Lipoxin A4 negatively regulates lipopolysaccharide-induced differentiation of RAW264.7 murine macrophages into dendritic-like cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Lipoxins (LXs), endogenous anti-inflammatory and pro-resolving eicosanoids generated during various inflammatory conditions, have novel immunomodulatory properties. Because dendritic cells (DCs) play crucial roles in the initiation and maintenance of immune response, we determined whether LXs could modulate the maturation process of DCs and investigated the effects of lipoxin A(4) (LXA(4)) on lipopolysaccharide (LPS)-induced differentiation of RAW264.7 cells into dendritic-like cells.</p><p><b>METHODS</b>RAW264.7 cells were cultured in vitro with 1 microg/ml LPS in the absence or presence of LXA(4) for 24 hours, and cellular surface markers (MHC-II, CD80 (B7-1), CD86 (B7-2)) were measured by flow cytometry (FCM). Mixed lymphocyte reaction was performed to evaluate the allostimulatory activity. Cytoplastic IkappaB degradation and nuclear factor kappa B (NF-kappaB) translocation were detected by Western blotting. Luciferase reporter plasmid was transiently transfected into RAW264.7 cells, and luciferase activity was determined to measure the transcriptional activity of NF-kappaB.</p><p><b>RESULTS</b>LXA(4) reduced the ratio of LPS-treated RAW264.7 cells to DCs with morphological characteristics and inhibited the expression of MHC II. LPS-induced up-regulation of CD86 was moderately suppressed by LXA(4) but no obvious change of CD80 was observed. Moreover, LXA(4) weakened the allostimulatory activity of LPS-treated RAW264.7 cells. These alterations of LPS+LXA(4)-treated cells were associated with a marked inhibition of IkappaB degradation, NF-kappaB translocation and then the transcriptional activity of NF-kappaB.</p><p><b>CONCLUSIONS</b>LXA(4) negatively regulates LPS-induced differentiation of RAW264.7 cells into dendritic-like cells. This activity reveals an undescribed mechanism of LXA(4) to prevent excessive and sustained immune reaction by regulating maturation of DCs.</p>

[Expression of hepatitis B surface antigen gene in ginseng cell].

The recombinant plasmid pBIBSa containing the HBsAg DNA fragment was transferred into Agrobacterium tumefaciens strain LBA4404 directly. Ginseng cells were co-cultivated with Agrobacterium tumefaciens carrying pBIBSa. The ginseng cell lines carrying HBsAg-S gene were obtained. Transgenic cells were checked for the presence of target gene using PCR and RT-PCR. Samples containing the target gene showed a clear band at the site of 700 bp by agarose electrophoresis analysis (Figs. 2, 3). Expression levels determined by ELISA showed maximum expression levels of 184 ng HBsAg/g FW and 0.009% of the total soluble protein. HBsAg in ginseng cells were located both on the membrane and in the nuclei (Fig. 4).