Therapeutic Fc fusion protein misfolding: A three-phasic cultivation experimental design.

Cell culture process optimization is a critical solution to most of the challenges faced by the pharmaceutical manufacturing. One of the major problems encountered in large-scale production of therapeutic proteins is misfolded protein production. The accumulation of misfolded therapeutic proteins is an immunogenic signal and a risk factor for immunogenicity of the final product. The aim of this study was the statistical optimization of three-phasic temperature shift and timing for enhanced production of correctly folded Fc-fusion protein. The effect of culture temperatures were investigated using the biphasic culture system. Box-Behnken design was then used to compute temperature and time of shifting optimum. Response surface methodology revealed that maximum production with low level of misfolded protein was achieved at two-step temperature shift from 37°C to 30°C during the late logarithmic phase and 30°C to 28°C in the mid-stationary phase. The optimized condition gave the best results of 1860 mg L-1 protein titer with 24.5% misfolding level. The validation experiments were carried out under optimal conditions with three replicates and the protein misfolding level was decreased by two times while productivity increased by ~ 1.3-fold. Large-scale production in 250 L bioreactor under the optimum conditions was also verified the effectiveness and the accuracy of the model. The results showed that by utilizing two-step temperature shift, productivity and the quality of target protein have been improved simultaneously. This model could be successfully applied to other products.

Cytotoxicity of ICD-85 NPs on Human Cervical Carcinoma HeLa Cells through Caspase-8 Mediated Pathway.

The biological application of nanoparticles (NPs) is a rapidly developing area of nanotechnology that raises new possibilities in the treatment of human cancers. The cytotoxicity was evaluated by MTT and LDH assays. The apoptotic effect of free ICD-85 and ICD-85 NPs on HeLa cells was assessed using caspase-8 colorimetric assay. The MTT assay showed that ICD-85 NPs could enhance the in-vitro cytotoxicity against HeLa cells compared to the free ICD-85. The IC50 value at 72 h was reduced from 25 ± 2.9 µg/mL for free ICD-85 to 15.5 ± 2.4 µg/mL for ICD-85 NPs. However, LDH assay demonstrated that ICD-85 has dose-dependent cytotoxicity on HeLa cells while ICD-85 NPs exhibited weaker cytotoxicity on same cells. The results also indicate that ICD-85-induced apoptosis on HeLa cells is associated with the activation of caspase-8. Moreover, caspase-8 assay analysis demonstrated that the ICD- 85 NPs induced a higher apoptotic rate in HeLa cells compared to free ICD-85. Our results demonstrated that the encapsulation of ICD-85 enhances its anti-proliferative effects. Taken together, these results suggest that the delivery of ICD-85 in nanoparticles may be a promising approach for the treatment of the cancer.

Comparative Cytotoxic Evaluation of Free and Sodium Alginate Nanoparticle-Encapsulated ICD-85 on Primary Lamb Kidney Cells.

BACKGROUND: Current anti-cancer drug therapy results in systemic side effects due to non-specific uptake by normal healthy noncancerous tissues. To alleviate this difficulty, many attempts have been devoted to the development of new delivery systems such as polymeric Nanoparticles (NPs). In this study, we prepared ICD-85 NPs based on sodium alginate and analyzed the cytotoxic activity of ICD-85 NPs relative to free ICD-85 on primary lamb kidney cells. METHODS: ICD-85 loaded sodium alginate nanoparticles were prepared by ionic gelation method and were characterized by the particle size, size distribution and Fourier Transform Infrared (FT-IR) spectroscopy. The in vitro cytotoxicity was evaluated by MTT assay and membrane integrity was evaluated by measuring Lactate Dehydrogenase (LDH) activity. The morphological alterations of untreated and treated cells were assessed by light inverted microscope. RESULTS: MTT assay showed that ICD-85 NPs could significantly decrease the in vitro cytotoxicity on primary lamb kidney cells compared to the free ICD-85. The IC10 value at 72 hours was increased from 9±2.7 µg/ml for free ICD-85 to 52±4.3 µg/ml for ICD-85 NPs. LDH assay demonstrated that free ICD-85 had dose-dependent cytotoxicity on primary lamb kidney cells while ICD-85 NPs exhibited significantly decreased cytotoxicity at equivalent concentrations. Moreover, morphological analysis showed no significant difference between control and treated cells with ICD-85 NPs. CONCLUSION: Based on the results obtained in the present study it can be concluded that encapsulation of ICD-85 with sodium alginate nanoparticles can reduce its necrotic effect on primary lamb kidney cells.

Cytotoxic effect of ICD-85 (venom-derived peptides) on HeLa cancer cell line and normal LK cells using MTT Assay.

BACKGROUND: Cancer is the fifth leading cause of death worldwide. There are considerable efforts to identify naturally occurring substances for use as new drugs in cancer therapy. Some components of animal venoms have been identified that possess substantial anticancer properties. In our previous studies, the cytotoxic effects of ICD-85 (venom-derived peptides) have been reported on HL-60 and MDA-MB231 cell lines. This has prompted us to investigate the comparative cytotoxic effects of ICD-85 on the HeLa cell line and normal lamb kidney (LK) cells. METHODS: Cells were exposed to various concentrations (8 × 10-4 to 5.6 × 10 µg/ml) of ICD-85 at various incubation times (24, 48 and 72 hours). Cell viability was measured by the MTT assay. A morphological study was also carried out using an inverted microscope. Caspase-8 activity was assayed by the Caspase-8 Colorimetric Assay Kit in HeLa cells that were exposed to ICD-85 for 48 hours. RESULTS: Data analysis showed that ICD-85 has a dose-dependent cytotoxic effect on HeLa cells with an inhibitory concentration 50% (IC50) of 26.62 ± 2.13 µg/ml at 24 hours, 27.33 ± 2.35 µg/ml at 48 hours, and 28.13 ± 2.52 µg/ml at 72 hours. Results also indicated that the cytotoxic effect of ICD-85, at 48 and 72 hours incubation times did not show significant alteration compared to 24 hours of exposure. Interestingly, the minimum concentration of ICD-85 which showed a cytotoxic effect on LK cells was found to be 3500-fold less than the minimum concentration that showed a cytotoxic effect on the HeLa cancer cells. While morphological analysis revealed a significant difference that included the characteristic rounding of dying cells by treatment with ICD-85 compared with untreated HeLa cells, this difference was not observed in normal cells. ICD-85 increased caspase-8 activity in HeLa cells after 48 hours of exposure. DISCUSSION: ICD-85 has a dose-dependent cytotoxic effect on HeLa cancer cells in contrast with its negligible effect on normal LK cells.

Necrotic Effect versus Apoptotic Nature of Camptothecin in Human Cervical Cancer Cells.

BACKGROUND: Functional defects in mitochondria are involved in the induction of cell death in cancer cells. The process of programmed cell death may occur through the mechanisms of apoptosis. Several potential lead molecules such as Camptothecin (CPT) and its analogues have been isolated from plants with anticancer effect. The aim of the present study was to understand the necrotic effect versus apoptotic nature of CPT in HeLa cancer cells. METHODS: The anti-proliferative activity of CPT was estimated through 3-(4, 5- Dimethyl Thiazol-2-yl)-2, 5-diphenyl Tetrazolium bromide (MTT) assay and DNA fragmentation analysis using gel electrophoresis. Lactate Dehydrogenase (LDH) activity and cell morphology were assessed under control and CPT exposed conditions to evaluate the necrotic effect of CPT. RESULTS: The results showed that CPT inhibited the proliferation of HeLa cells in a dose-dependent manner with an Inhibitory Concentration 50% (IC50) of 0.08±0.012 µg/ml. However the significant (p<0.05) increase happens in LDH activity at concentrations 1×10(-1)µg/ml and above. Morphological changes showed that CPT in low concentrations induced an apoptotic mechanism of cell death, such as cell shrinkage and characteristic rounding of dying cells, while at high concentrations showed necrosis changes. The characteristic DNA ladder formation of CPT-treated cells in agarose gel electrophoresis confirmed the results obtained by light microscopy and LDH assay. CONCLUSION: Camptothecin as an anticancer drug may have anti-proliferative effect on HeLa cancer cells in low concentrations, through its nature of induction of apoptosis. The border line between necrotic effect and apoptotic nature of CPT in HeLa cancer cells has been found to be at concentration of 1×10(-1) µg/ml.