Viable mononuclear cell stability study for implementation in a proficiency testing program: impact of shipment conditions

Compartmentalized role of xCT in supporting pancreatic tumor growth, inflammation and mood disturbance in mice

xCT (Slc7a11), the specific subunit of the cystine/glutamate antiporter system xc-, is present in the brain and on immune cells, where it is known to modulate behavior and inflammatory responses. In a variety of cancers -including pancreatic ductal adenocarcinoma (PDAC)-, xCT is upregulated by tumor cells to support their growth and spread. Therefore, we studied the impact of xCT deletion in pancreatic tumor cells (Panc02) and/or the host (xCT-/- mice) on tumor burden, inflammation, cachexia and mood disturbances. Deletion of xCT in the tumor strongly reduced tumor growth. Targeting xCT in the host and not the tumor resulted only in a partial reduction of tumor burden, while it did attenuate tumor-related systemic inflammation and prevented an increase in immunosuppressive regulatory T cells. The latter effect could be replicated by specific xCT deletion in immune cells. xCT deletion in the host or the tumor differentially modulated neuroinflammation. When mice were grafted with xCT-deleted tumor cells, hypothalamic inflammation was reduced and, accordingly, food intake improved. Tumor bearing xCT-/- mice showed a trend of reduced hippocampal neuroinflammation with less anxiety- and depressive-like behavior. Taken together, targeting xCT may have beneficial effects on pancreatic cancer-related comorbidities, beyond reducing tumor burden. The search for novel and specific xCT inhibitors is warranted as they may represent a holistic therapy in pancreatic cancer.

Whole serum as cell protection reagent in cell shipment at low or room temperature

To maintain cell viability and characteristics physiological over long time or long-distance cell shipment is critical to promote the collaborative efforts in the research field of cell biology. Herein, we investigated the possibility of different concentration of fetal bovine serum as transport cell reagent. Cell suspension of three different mammalian cell lines were transported in 1.5 mL tube under different temperature conditions. Cell viability was closely related to environmental temperature and shipment time. No significant difference of cell survival rate was observed between 2-8 ℃ and 8-16 ℃ groups, under these two temperature conditions, reagent containing above 50 % FBS showed the best protection effect to maintain over 80 % cell survival rate. After 10 days of cell shipment under 2-16 ℃ environmental temperature, C3H10 cells exhibited the same multiple differentiation ability, 143B cells had the same capability of proliferation, migration and invasion, LX-2 cells showed the same activation state with TGF-β stimulation. Three cell lines maintained their primary characteristics after long time cell shipment. This entire shipment process does not require the maintenance of specific temperatures, humidity and container, providing a low-costing and convenient way for cell shipment between long distance laboratories.

OUP accepted manuscript

Advances in regenerative medicine manufacturing continue to be a priority for achieving the full commercial potential of important breakthrough therapies. Equally important will be the establishment of distribution chains that support the transport of live cells and engineered tissues and organs resulting from these advanced biomanufacturing processes. The importance of a well-managed distribution chain for products requiring specialized handling procedures was highlighted during the COVID-19 pandemic and serves as a reminder of the critical role of logistics and distribution in the success of breakthrough therapies. This perspective article will provide insight into current practices and future considerations for creating global distribution chains that facilitate the successful deployment of regenerative medicine therapies to the vast number of patients that would benefit from them worldwide.

Actual approaches to the transportation of biological samples at low temperatures

Taking into account the impact of shipment method of biosamples is necessary for obtaining high-quality biological samples in biobanking and laboratory research. The impact of liquid nitrogen, dry ice and cold accumulators on the quality of biological markers was considered, as well as recommendations to reduce the impact of these methods of shipment. The liquid nitrogen provides the best preservation of samples, however, dry ice is used much more often during their transportation. When transporting certain types of cells using dry ice, there is the way to use CryoStor CS1 and Cell Banker 1 cryoprotectors. The dry ice has a significant effect on both the pH of liquid biological samples and the coagulological parameters of plasma samples. The penetration of CO2 into the sample leads to changes in the parameters of PTT and APPT, as well as to decrease the protein C and fibrinogen level under certain conditions. Serum and plasma samples exposed to dry ice for more than 16 hours should be thawed open at room temperature, or instead of it should be kept at -80 °C for 24 hours to avoid changes in coagulation parameters, The use of cold accumulators is unacceptable for long-term shipment of serum and plasma containing unstable biomarkers because of insufficiently low temperature (increase over time to -25 °C and above). Besides, metal pellets can be used as cold storage batteries at low temperatures (up to -80 ° C), but they are not as effective as dry ice, since it is able to hold the required temperature for much longer.

Cryopreservation affected the levels of immune responses of PBMCs and antigen-presenting cells

The effect of cryopreservation on antigen-presenting cells (APCs) is understudied. It is important to understand the effects of cryopreservation on these cells as they play a major role in immune responses, and they could be utilized in different clinical applications. In this study, we compared fresh and cryopreserved PBMCs in regards of their general immune responsiveness and, furthermore, the effect of cryopreservation on the circulating APCs among PBMCs. We stimulated fresh and cryopreserved PBMCs (N = 6) with LPS or Poly(I:C).Cytokine production of PBMCs and expression of functional markers CD80 and ILT4 on major types of APCs, dendritic cells (DCs) and monocytes, were analysed. We also analysed whether cryopreservation affects different subtypes of DCs (plasmacytoid and myeloid DCs) differently. Cryopreserved PBMCs produced less cytokines than fresh cells in response to stimulation, but the response profiles were comparable. Cryopreservation had also an effect on the relative proportions of APCs. Stimuli-induced responses were somewhat parallel but weaker than those observed in fresh cells. This study suggests that the use of cryopreserved cells is more suitable in studies that assess general responses to stimuli instead of measuring exact levels of reactions. Thus, the interpretation and comparison of the results of different studies should not be done without considering the differences in cryopreservation techniques and their effects on PBMCs and, more specifically, on APCs.

Observation and quantification of the morphological effect of trypan blue rupturing dead or dying cells

Trypan blue has long been the gold standard for staining dead cell to determine cell viability. The dye is excluded from membrane-intact live cells, but can enter and concentrate in membrane-compromised dead cells, rendering the cells dark blue. Over the years, there has been an understanding that trypan blue is inaccurate for cell viability under 80% without scientific support. We previously showed that trypan blue can alter the morphology of dead cells to a diffuse shape, which can lead to over-estimation of viability. Here, we investigate the origin of the dim and diffuse objects after trypan blue staining. Utilizing image and video acquisition, we show real-time transformation of cells into diffuse objects when stained with trypan blue. The same phenomenon was not observed when staining cells with propidium iodide. We also demonstrate the co-localization of trypan blue and propidium iodide, confirming these diffuse objects as cells that contain nuclei. The videos clearly show immediate cell rupturing after trypan blue contact. The formation of these diffuse objects was monitored and counted over time as cells die outside of the incubator. We hypothesize and demonstrate that rapid water influx may have caused the cells to rupture and disappear. Since some dead cells disappear after trypan blue staining, the total can be under-counted, leading to over-estimation of cell viability. This inaccuracy could affect the outcomes of cellular therapies, which require accurate measurements of immune cells that will be infused back into patients.

Testosterone induced downregulation of migration and proliferation in human Umbilical Vein Endothelial Cells by Androgen Receptor dependent and independent mechanisms

Recent research has emphasized the potential unfavorable effects of declining testosterone (T) levels in men and the putative beneficial effect of androgen therapy in select women. Some controversy surrounding the mechanism of action and the effects of T on endothelium remains. In this study, we evaluated the mechanism of T action on pooled primary Human Umbilical Vein Endothelial Cells (HUVEC) of mixed gender by focusing on two important processes, proliferation and migration. In our in vitro model system, we found that only the supra-physiological dose of T affected these two processes irrespective of the ratio of male to female cells in the pools. At a concentration of 1 μM, T downregulated the proliferation of HUVEC by inducing arrest in the G1 cell cycle phase in an Androgen Receptor (AR)-independent manner. We show that treatment with 1 μM T also induced downregulation of HUVEC migration. This process was AR-dependent and was associated with persistent phosphorylation of ezrin, radixin and moesin. Regardless of the mechanism of action, the treatment of HUVEC with both supra- and physiological doses of T was associated with posttranscriptional stabilization of the AR upon ligand binding.

Impact of Specimen Heterogeneity on Biomarkers in Repository Samples from Patients with Acute Myeloid Leukemia: A SWOG Report

INTRODUCTION

Current prognostic models for acute myeloid leukemia (AML) are inconsistent at predicting clinical outcomes for individual patients. Variability in the quality of specimens utilized for biomarker discovery and validation may contribute to this prognostic inconsistency.

METHODS

We evaluated the impact of sample heterogeneity on prognostic biomarkers and methods to mitigate any adverse effects of this heterogeneity in 240 cryopreserved bone marrow and peripheral blood specimens from AML patients enrolled on SWOG (Southwest Oncology Group) trials.

RESULTS

Cryopreserved samples displayed a broad range in viability (37% with viabilities ≤60%) and nonleukemic cell contamination (13% with lymphocyte percentages >20%). Specimen viability was impacted by transport time, AML immunophenotype, and, potentially, patients' age. The viability and cellular heterogeneity in unsorted samples significantly altered biomarker results. Enriching for viable AML blasts improved the RNA quality from specimens with poor viability and refined results for both DNA and RNA biomarkers. For example, FLT3-ITD allelic ratio, which is currently utilized to risk-stratify AML patients, was on average 1.49-fold higher in the viable AML blasts than in the unsorted specimens.

CONCLUSION

To our knowledge, this is the first study to provide evidence that using cryopreserved specimens can introduce uncontrollable variables that may impact biomarker results and enrichment for viable AML blasts may mitigate this impact.

Easy and low-cost stable positioning of suspension cells during live-cell imaging

Dynamic processes of cells can be best monitored when living cells are analyzed by imaging. While it is easy to observe adherent living cells it has been extremely challenging to analyze suspension cells. This cell type floats freely in the culture dish, and it is only a question of time when the focus or the observation field is lost. In order to keep the cells in focus, an easy and inexpensive method allowing the observation of living suspension cells during confocal laser scanning microscope imaging was developed.

A Biospecimen Proficiency Testing Program for Biobank Accreditation: Four Years of Experience

Biobanks produce and distribute biospecimens, ensuring their fitness for purpose and accurately qualifying them before distribution. In their efforts toward professionalization, biobanks can nowadays seek certification or accreditation. One of the requirements of these standards is regular participation in Proficiency Testing (PT) programs. An international PT program has been developed and provided to biobanks and other laboratories that perform specific tests to qualify different types of biospecimens. This PT program includes biospecimen testing schemes, as well as biospecimen processing interlaboratory exercises. This PT program supports the development of biobank quality assurance by providing the possibility to assess biobank laboratory performance and useful insights into biobank laboratory method performance characteristics and thus fulfill the demands from accreditation authorities.