Gene expression profiling of circulating tumor cells and peripheral blood mononuclear cells from breast cancer patients.

Circulating tumor cells (CTCs) are cancer cells that are released from a tumor into the bloodstream. The presence of CTCs in peripheral blood has been associated with metastasis formation in patients with breast cancer. Therefore, the molecular characterization of CTCs may improve diagnostics and support treatment decisions. We performed gene expression profiling to evaluate the enriched CTCs and peripheral blood mononuclear cells (PBMCs) of breast cancer patients using an expression panel of 55 breast cancer-associated genes. The study revealed several significantly differentially expressed genes in the CTC-positive samples, including a few that were exclusively expressed in these cells. However, the expression of these genes was barely detectable in the PBMC samples. Some genes were differentially expressed in PBMCs, and the expression of these genes was correlated with tumor grade and the formation of metastasis. In this study, we have shown that the enriched CTCs of breast cancer patients overexpress genes involved in proteolytic degradation of the extracellular matrix (ECM) as well as genes that play important roles in the epithelial-mesenchymal transition (EMT) process that may occur in these cells.

High hydrostatic pressure induces immunogenic cell death in human tumor cells.

Recent studies have identified molecular events characteristic of immunogenic cell death (ICD), including surface exposure of calreticulin (CRT), the heat shock proteins HSP70 and HSP90, the release of high-mobility group box protein 1 (HMGB1) and the release of ATP from dying cells. We investigated the potential of high hydrostatic pressure (HHP) to induce ICD in human tumor cells. HHP induced the rapid expression of HSP70, HSP90 and CRT on the cell surface. HHP also induced the release of HMGB1 and ATP. The interaction of dendritic cells (DCs) with HHP-treated tumor cells led to a more rapid rate of DC phagocytosis, upregulation of CD83, CD86 and HLA-DR and the release of interleukin IL-6, IL-12p70 and TNF-α. DCs pulsed with tumor cells killed by HHP induced high numbers of tumor-specific T cells. DCs pulsed with HHP-treated tumor cells also induced the lowest number of regulatory T cells. In addition, we found that the key features of the endoplasmic reticulum stress-mediated apoptotic pathway, such as reactive oxygen species production, phosphorylation of the translation initiation factor eIF2α and activation of caspase-8, were activated by HHP treatment. Therefore, HHP acts as a reliable and potent inducer of ICD in human tumor cells.

Novel human multiple myeloma cell line UHKT-893.

UNLABELLED: We established and characterized a new IL-6 dependent multiple myeloma (MM) cell line UHKT-893 from the bone marrow of a relapsed 57-year-old woman. RESULTS: Using nephelometry, cells with plasma cell phenotype and morphology were found to secrete IgG and free kappa (κ)-light chain of immunoglobulin. κ-Light chain was also recognized intracellularly by flow cytometry and by mass spectrometry. VH4-39 region of IgVH genes was rearranged and somatically hypermutated. Cytogenetic analysis of cells revealed new chromosome abnormalities in all breakpoints unique in both MM patients and cell lines - t(1;6), t(1;11), t(5;15), t(5;21), +der(11;15) and der(16). IL-6 independent subline UHKT-893a was established by adaptation to descending IL-6 concentration, while the original cell line keeps on maintaining its IL-6 dependency. CONCLUSION: The cell line provides a suitable material for cellular and molecular studies of tumor abnormalities, with potentially unique mutagenic features of myeloma disease. It may be utilized for human hybridoma construction and vaccine development. Both IL-6 dependent and independent cell clones represent an important model for studies of myeloma cell growth and resistance emerging during targeted therapy.