2'-Deoxycytidine decreases the anti-tumor effects of 5-fluorouracil on mouse myeloma cells

Mathematical reconstruction of the metabolic network in an in-vitro multiple myeloma model

It is increasingly apparent that cancer cells, in addition to remodelling their metabolism to survive and proliferate, adapt and manipulate the metabolism of other cells. This property may be a telling sign that pre-clinical tumour metabolism studies exclusively utilising in-vitro mono-culture models could prove to be limited for uncovering novel metabolic targets able to translate into clinical therapies. Although this is increasingly recognised, and work towards addressing the issue is becoming routinary much remains poorly understood. For instance, knowledge regarding the biochemical mechanisms through which cancer cells manipulate non-cancerous cell metabolism, and the subsequent impact on their survival and proliferation remains limited. Additionally, the variations in these processes across different cancer types and progression stages, and their implications for therapy, also remain largely unexplored. This study employs an interdisciplinary approach that leverages the predictive power of mathematical modelling to enrich experimental findings. We develop a functional multicellular in-silico model that facilitates the qualitative and quantitative analysis of the metabolic network spawned by an in-vitro co-culture model of bone marrow mesenchymal stem- and myeloma cell lines. To procure this model, we devised a bespoke human genome constraint-based reconstruction workflow that combines aspects from the legacy mCADRE & Metabotools algorithms, the novel redHuman algorithm, along with 13C-metabolic flux analysis. Our workflow transforms the latest human metabolic network matrix (Recon3D) into two cell-specific models coupled with a metabolic network spanning a shared growth medium. When cross-validating our in-silico model against the in-vitro model, we found that the in-silico model successfully reproduces vital metabolic behaviours of its in-vitro counterpart; results include cell growth predictions, respiration rates, as well as support for observations which suggest cross-shuttling of redox-active metabolites between cells.

Immunophenotyping of classic murine myeloma cell lines used for monoclonal antibody production

Murine myeloma cell lines play an important role in different areas of scientific research and are essential tools for monoclonal antibody production technology. Thus, it is important to understand the biology of these cell lines in order to provide useful information to various research fronts. The present study aims to perform detailed analyses of surface antigens expressed on three major murine myeloma cell lines extensively used for MAb production. The P3X63Ag8.653 cell line expresses molecules associated with T cell interaction (CD40(low), CD80(low)), as well as antigens related to plasma cell phenotype (CD138(high), CD184(low)). The Sp2/0-Ag14 cell line presents molecules associated with BCR activation and regulation (CD79b(low), CD22(low), CD72(med)), molecules related to T cell interaction (CD40(low), CD80(low)), and markers of plasma cell phenotype (CD138(high), CD184(low)). The NS1 cell line presents all molecules of plasma cell phenotype evaluated in this study (CD184(low), CD138(high), CD38(med)) with low expression of CD72 (CD72(low)), a molecule related to BCR activation. Molecules associated with immune response modulation such as CD23 and CD25, as well as CD117, a marker related to undifferentiated cell phenotype, were not observed in any of the three murine myeloma cell lines evaluated. These data show that in spite of their common origin and function, the immunological profiles differ between P3X63Ag8.653, Sp2/0-Ag14, and NS1 cell lines.

Changes in 2'-deoxycytidine levels in various tissues of tumor-bearing mice

The nucleoside 2'-deoxycytidine (dCyd) increases in the plasma of cancer patients with poor prognoses. 5-fluorouracil (5FU) is one of the anti-cancer agents used in chemotherapy for patients whose plasma dCyd is elevated. We examined the free dCyd level in various tissues of mice, with and without tumors, and in mice with and without the administration of 5FU or of dCyd, and investigated the effects of dCyd in tumor-bearing animals. SP2/0-Ag14 mouse myeloma cells were transplanted subcutaneously into mice and 5FU or dCyd was administered intraperitoneally. Free dCyd was measured in blood and tissues by HPLC at two time points, once when mouse body weight was maximally decreased (1 day after the last administration of 5FU, day 16) and again when it returned to control level at 1 week after the last 5FU treatment (day 22). Results showed that in tumor-bearing mice, the level of dCyd (per g wet weight) increased in the spleen. The change in liver weight caused by the administration of 5FU correlated with the level of dCyd in the liver. Notably, the relative tumor volume and tumor weight was decreased in dCyd-treated animals in comparison with controls. In conclusion, the levels of dCyd were markedly altered in the tissues of the reticuloendothelial and lymphatic systems, such as liver and spleen, and dCyd apparently had the ability to inhibit tumor growth in the body.