Triple-negative and triple-positive breast cancer cells reciprocally control their growth and migration via the S100A4 pathway.

The study's aim was to investigate the S100A4-mediated mechanisms of the regulation of tumor cell proliferation and migration in the human triple-positive breast carcinoma cell line MCF-7 (TPBC) and triple-negative breast carcinoma cell line MDA-MB-231 (TNBC). The proliferative activity of TNBC more than doubled during the incubation in the conditioned medium of TPBC. Extracellular S100A4 dose-dependently decreased the proliferative response of TPBC.

Thapsigargin, Inhibitor of Sarco-Endoplasmic Ca-ATPase, Effectively Suppresses the Expression of S100A4 Protein in Human Breast Cancer Cell Line.

Thapsigargin (SERCA ATPase inhibitor) inhibited the S100A4 metastatic marker expression in MDA-MB231 breast cancer cells. We found that S100A4 gene transcription is regulated by Ca signaling pathways. We found that the synthesis of S100A4 mRNA and S100A4 protein in MDA-MB231 cells was effectively suppressed by thapsigargin at a concentration of 0.

The Expression Level of S100A4 Protein Affects the Migration Activity of Breast Cancer Cells.

Reduced expression of metastatic marker protein S100A4 in triple-negative breast cancer cells MDA-MB-231 leads to a decrease in the migration ability of cells and increases the sensitivity of the modified cells to docetaxel therapy. Cells capable of migration differ from the immotile cells in the content of the S100A4 protein in the cell, and this difference persists after the treatment of cells with the agents that reduce the intracellular level of S100A4. The presence of exogenous S100A4 protein in culture medium reduces the content of this protein in breast cancer cells.

Studying of the Mechanisms of Combined Effect of Dexamethasone, Doxorubicin, and Docetaxel on Breast Cancer Cells.

The sensitivity of MDA-MB231 breast cancer cells to the effects of pharmacological agents was evaluated by their motility and viability. Dexamethasone, doxorubicin, or docetaxel administered separately in their effective concentration suppressed cell motility (in 16 h) and caused cell death (in 48 h). The strength of the effects increased in the following order: dexa methasone View Article and Find Full Text PDF

Combined Action of PGRPs-Hsp70 Cytotoxic Complex with Paclitaxel Improves Outcomes of Melanoma Treatment in Mice.

We studied the effect of PGRPs-Hsp70 cytotoxic complex that is analogous to natural complex secreted by cytotoxic lymphocytes and the antitumor drug paclitaxel on the development of M3 melanoma in DBA mice. Significant inhibition of tumor growth was observed in all experimental groups by days 20 and 35 of observation; paclitaxel monotherapy was less effective than administration of PGRPs-Hsp70 cytotoxic complex and its combination with paclitaxel. Pairwise comparison of Kaplan-Meier curves showed that survival was maximum in the group receiving combined therapy with PGRPs-Hsp70 cytotoxic complex and paclitaxel in comparison with groups receiving monotherapy.

The role of S100A4 protein in anticancer cytotoxicity: its presence is required on the surface of CDCDPGRPsS100A4 lymphocyte and undesirable on the surface of target cells.

S100A4 is a Ca-binding protein that performs an important role in metastasis. It is also known for its antitumor functions. S100A4 is expressed by a specialized subset of CDCD lymphocytes and is present on those cell's membranes along with peptidoglycan recognition proteins (PGRPs).

Lymphocytes incubated in the presence of IL-2 lose the capacity for chemotaxis but acquire antitumor activity.

Naïve non-activated lymphocytes are capable of releasing the chemoattractant complex Tag7-Mts1 and can migrate along the gradient of its concentration. After activation of these cells by IL-2, they acquire the abilities to kill tumor cells and to release the cytotoxic Tag7-Hsp70 complex, which is accompanied by a loss of both the Tag7-Mts1-mediated lymphocyte chemotaxis and the ability to release this chemoattractant into the conditioned medium.

Transcription factor Oct-1 stimulates the release of Mts1/S100A4 protein by the cancer cells.

The effect of the transcription factor Oct-1 (POU2F1) on the expression of the tumor cell marker metastasin (Mts1/S100A4) was studied. Comparative analysis of various tumor lines showed no clear correlation between the expression level of Mts1/S100A4 and the content of Oct-1. However, at stable transfection of tumor cells with Oct-1A, Oct-1L, and Oct-1X isoforms we detected an elevated level of Oct-1, which stimulated Mts1/S100A4 secretion.

Oct-1 modifies S100A4 exchange between intra- and extracellular compartments in Namalwa cells and increases their sensitivity to glucocorticoids.

S100A4, a small intra- and extracellular Ca(2+)-binding protein, is involved in tumor progression and metastasis with S100A4 level shown to be correlated with tumor cells metastatic potential. Simultaneously, Octamer transcription factor 1 (Oct-1) regulates a wide range of genes and participates in tumor cell progression with high Oct-1 level associated with a poor prognosis for different tumors. In this study, following the establishment of Oct-1 binding site, we used Burkit lymphoma B cells (Namalwa cells) which express different isoforms of Oct-1 (Oct-1A, Oct-1L and Oct-1X) to investigate the role of Oct-1 in S100A4 expression and sustaining intra- and extra-cellular S100A4 levels.

A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1.

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7-Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target.

Tag7 (PGLYRP1) in Complex with Hsp70 Induces Alternative Cytotoxic Processes in Tumor Cells via TNFR1 Receptor.

Tag7 (also known as peptidoglycan recognition protein PGRP-S, PGLYRP1), an innate immunity protein, interacts with Hsp70 to form a stable Tag7-Hsp70 complex with cytotoxic activity against some tumor cell lines. In this study, we have analyzed the programmed cell death mechanisms that are induced when cells interact with the Tag7-Hsp70 complex, which was previously shown to be released by human lymphocytes and is cytotoxic to cancer cells. We show that this complex induces both apoptotic and necroptotic processes in the cells.

Extracellular HspBP1 inhibits formation of a cytotoxic Tag7-Hsp70 complex in vitro and in human serum.

Tag7 (PGRP-S) was described as an innate immunity protein. Earlier we have shown that Tag7 forms with Hsp70 a stable complex with cytotoxic and antitumor activity. The same complex is formed in and secreted by cytotoxic T-lymphocytes.

The heat shock-binding protein (HspBP1) protects cells against the cytotoxic action of the Tag7-Hsp70 complex.

Heat shock-binding protein HspBP1 is a member of the Hsp70 co-chaperone family. The interaction between HspBP1 and the ATPase domain of the major heat shock protein Hsp70 up-regulates nucleotide exchange and reduces the affinity between Hsp70 and the peptide in its peptide-binding site. Previously we have shown that Tag7 (also known as peptidoglycan recognition protein PGRP-S), an innate immunity protein, interacts with Hsp70 to form a stable Tag7-Hsp70 complex with cytotoxic activity against some tumor cell lines.

Unexpected deeds of familiar proteins: Interplay of Hsp70, PGRP-S/Tag7 and S100A4/Mts1 in host vs. cancer combat.

We consider the novel means of attack and defense in the host versus cancer combat that involve interactions between widespread multifunctional proteins, focusing on the aspects that may seem paradoxical in the framework of established notions. Particularly, we show that a protein broadly known for its protective functions such as Hsp70 can make a tumoricidal "binary weapon" with another nontoxic protein Tag7 (PGRP-S); that the same Hsp70, a ubiquitous intracellular chaperone, when expressed on the MHC-negative tumor cell surface, can itself be the hallmark of immune evasion rather than a primordial MHC substitute; that a device functionally equivalent to the T-cell receptor (Tag7-Centered Recognizer) can be assembled of components in no way related to the classical pathways of T-cell-mediated immunity, and operate where the orthodox immunosurveillance fails; and that one and the same protein Mts1 (S100A4) under different circumstances may work as "reactive armor" of a tumor cell against humoral agents and as a vital part of the T-cell machinery aimed against immunoevasive cells, i.e.

Opposite roles of metastasin (S100A4) in two potentially tumoricidal mechanisms involving human lymphocyte protein Tag7 and Hsp70.

We compare the physical and functional interactions between three widespread multifunctional proteins [metastasin (Mts1/S100A4), innate immunity-related Tag7/PGRP-S, and Hsp70] in two experimental models relevant to host-tumor relationships on humoral and cellular levels. (i) Tag7 and Hsp70 in solution or in a lymphocyte make a stable binary complex that is highly cytotoxic for some tumor cells. Here, we show that Mts1 prevents Tag7.

Comparative analysis of secretion of S100A4 metastatic marker by immune and tumor cells.

S100A4 protein is present in low concentrations (2.1-15.7 ng/10(6) cells) in lymphocyte and neutrophil culture medium.

Interactions and possible functional characteristics of Tag7-S100A4 protein complex.

Peptidoglycane-recognizing protein Tag7 formed a complex with S100A4 (a representative of S100 protein family), the apparent dissociation constants in the absence and presence of Ca2+ were 2 x l0(-8) M and 10(-9) M, respectively. Analysis of fluorescence spectra of hydrophobic fluorescent probe 2-toluidinyl naphthalene-6-sulfonate in the presence of S100A4 and Tag7 proteins showed that extensive area or several sites are involved into the complex formation between these proteins. The formation of Tag7-S100A4 complex had virtually no effect on the role of S100A4 in the regulation of intracellular Ca2+ metabolism.

Cytotoxic T lymphocytes carrying a pattern recognition protein Tag7 can detect evasive, HLA-negative but Hsp70-exposing tumor cells, thereby ensuring FasL/Fas-mediated contact killing.

Within the broad problem of host immune surveillance versus tumor immune evasion, a most intriguing question is how the cellular immunity can cope with cancerous cells that have gotten rid of the classical antigen-presenting machinery. One such option stems from (1) the fact that HLA loss is often attended with expression of Hsp70 on the tumor cell surface, and (2) our findings that human lymphocytes express a protein Tag7 (also known as PGRP-S) capable of tight and specific interaction with cognate Hsp70. Here we show that a subpopulation of human CD4(+)CD25(+) lymphocytes, obtained either in culture as lymphokine-activated killers or directly from healthy donors, carry Tag7 and FasL on their surface and can indeed kill the HLA-negative tumor-derived cells K562 and MOLT-4 that expose Hsp70 and Fas.

Peptidoglycan recognition protein tag7 forms a cytotoxic complex with heat shock protein 70 in solution and in lymphocytes.

The peptidoglycan recognition protein Tag7 is shown to form a stable 1:1 complex with the major stress protein Hsp70. Neither protein is cytotoxic by itself, but their complex induces apoptotic death in several tumor-derived cell lines even at subnanomolar concentrations. The minimal part of Hsp70 needed to evoke cytotoxicity is residues 450-463 of its peptide-binding domain, but full cytotoxicity requires its ATPase activity; remarkably, Tag7 liberated from the complex at high ATP is not cytotoxic.