Cell function profiling to assess clone stability

DirectedCHO: A new miniaturized directed evolution process for phenotype stability trial test of CHO cells before bioreactor scale-up

Most of the biopharmaceuticals that are currently on the market are expressed using the Chinese Hamster Ovary (CHO) cell lines. However, the production yield of these biopharmaceuticals is affected due to CHO cellular heterogeneity and challenges in adaptability during the bioreactor scale-up stage. In this communication, we report the protocol for the miniaturized directed evolution process for CHO cells. The results of the directed evolution process would guide adapting the CHO cell line before bioreactor scale-up. With our approach, we have established the protocol that can be used to streamline superior CHO cell lines for biopharmaceutical production which would be the first of its kind in Africa. Our directed evolution protocol includes a method for a low-cost multiplex directed evolution process that can be used on CHO cells using 20 stressors in 8 concentrations and provides stable trial results for the scale-up process. Using our process, we can provide a simple consumable kit that manufacturers can use for the CHO cell phenotype stability test before the scale-up process. With our approach, we would further develop a platform that can streamline superior CHO cell lines for biopharmaceutical production. This approach would be the first of its kind in South Africa/ Africa.

Promotion of colorectal cancer cell death by ezetimibe via mTOR signaling-dependent mitochondrial dysfunction

Introduction: Colorectal cancer (CRC) is the fourth most common cancer worldwide, with high morbidity and mortality rates. In recent years, high-fat diet has been shown to increase CRC morbidity, highlighting the possibility of the application of hypolipidemic drugs for CRC treatment. In this study, we preliminarily evaluated the effects and mechnisms of ezetimibe against CRC through the blockage of lipid absorption in small intesine. Methods: In this study, CRC cell proliferation, invasion, apoptosis, and autophagy were evaluated using cellular and molecular assays. Fluorescent microscopy, and a flow cytometric assay were used to assess mitochondrial activity in vitro. A subcutaneous xenograft mouse model was used to evaluate the effects of ezetimibe in vivo. Results: We found that ezetimibe inhibited CRC cell proliferation, and migration, and facilitated autophage-associated apoptosis in HCT116 and Caco2 cells. Ezetimibe-induced mitochondrial dysfunction in CRC cells was found to be correlated with mTOR signaling activity. Discussion: Ezetimibe exhibits effects against CRC through the promotion of cancer cell death via mTOR signaling-dependent mitochondrial dysfunction, highlighting its potential value in CRC therapy.

Downregulation of MACC1 facilitates the reversal effect of verapamil on the chemoresistance to active metabolite of irinotecan in human colon cancer cells

The aim of this study is to investigate the reversal effect of verapamil (VER) on chemoresistance to irinotecan (CPT-11) in human colon cancer cells and relevant mechanisms. Cell counting kit-8 (CCK-8) test and colony-forming unit (CFU) experiment results show that VER strengthens the sensitivity of human colon cancer cell line HT29 to CPT-11 but has a small effect on SW480 cells. High-throughput transcriptome sequencing, RT-PCR, and Western blot results show that the inhibition of metastasis-associated in colon cancer-1 (MACC1) expression by VER is the key factor for reversal effect on chemoresistance to CPT-11. Transfection experiments further show that VER can reverse the resistance of human colon cancer cells to SN-38, the active metabolite of CPT-11, when MACC1 is overexpressed. The nude mouse transplantation tumor experiment provides an in vivo proof that VER can strengthen sensitivity to CPT-11 in drug-resistant human colon cancer cells, and the effect might be related to the inhibited expression of MACC1. In summary, VER might strengthen the reversal effect of VER on chemoresistance to CPT-11 in human colon cancer cells and facilitate the apoptosis of human colon cancer cells by downregulating MACC1 expression.

Cell function profiling to assess clone stability

In cell line development the identification of stable Chinese hamster ovary cells for production is a critical but onerous task. The stability trial focus upon high‐level attributes can mask profound underlying cellular changes, leading to unstable clones mistakenly being chosen for production. The challenge is to assay underlying cell pathways and subsystems without pushing up cell line development costs. ChemStress® cell function profiling is a simple, multiwell plate‐based assay that uses a panel of active chemicals to mimic known bioprocess stresses and challenge key pathways. After 3 days of static culture on the plate, functional responses are assayed, for example, titer and growth. Here this approach is used to monitor 131 clones as they change over real stability trials. A novel stability metric is defined over the data to identify stable clones that remain unperturbed across many components of cell function. This allows stability trials to look beneath the titer to identify clones that are internally more stable.