Caractérisation de l'activité cytotoxique naturelle des cellules Foà-Kurloff

Les cellules Kurloff sont des cellules mononuclées spécifiques du cobaye et caractérisées par la présence d'un grand corps d'inclusion cytoplasmique. Le présent travail traite principalement de l'étude de leurs mécanismes de cytotoxicité naturelle in vitro par essai de relâchement spécifique de 51Cr. En utilisant des populations purifiées (>95%) de cellules Kurloff et diverses lignées cellulaires cibles, nous avons observé que l'activité cytotoxique NK (Natural Killer) des cellules Kurloff était sélective, démontrant une forte activité contre la cellule cible murine NK-sensible YAC-1, une activité intermédiaire contre la cellule cible humaine NK-sensible K562 et une activité minimale contre la cellule cible NK-résistante P815. La cytotoxicité des cellules Kurloff était considérablement augmentée contre les deux cibles murines YAC-1 et P815 en présence de PHA mais n'était pas modifiée par le prétraitement des cellules effectrices avec la lectine. L'inhibition de l'activité NK des cellules Kurloff par chélation du Ca++ ou par prétraitement avec les bloqueurs calciques, vérapamil et diltiazem, indiquent que l'activité cytotoxique des cellules Kurloff est dépendante de la présence de Ca++ extracellulaire et de l'influx de Ca++ extracellulaire dans la cellule effectrice. De plus, l'activité cytotoxique des cellules Kurloff était considérablement augmentée en présence de l'ester de phorbol TPA et partiellement inhibée par l'inhibiteur de la PKC, H-7. Ceci suggère un rôle de la PKC dans l'activation du programme lytique des cellules Kurloff. L'inhibition de l'activité cytotoxique des cellules Kurloff par le monensin suggère que la lyse des cellules cibles est médiée via le relâchement de facteurs cytotoxiques par les cellules Kurloff, parmi lesquels les sérine estérases seraient possiblement impliquées. Les cellules Kurloff ont aussi démontré une forte activité cytotoxique contre les cellules cibles TNF-sensibles WEHI 164 dans les essais de 18 heures. Une cytotoxicité moindre, mais significative était également observée après seulement 4 heures. Toutefois, nos résultats suggèrent des mécanismes de lyse différents dans les essais de 18 heures et de 4 heures. La Iyse des cellules WEHI 164 par les cellules Kurloff dans l'essai de 4 heures était considérablement augmentée en présence de TPA seul ou de TPA + ionomycine tandis que l’ionomycine seule n'avait aucun effet. Au contraire, la stimulation des cellules Kurloff pendant 18 heures avec l’ionomycine seule était suffisante pour induire le relâchement de facteur(s) TNF-like tel que démontré par bioessai de TNF en utilisant les cellules cibles TNF-sensibles, L-929. Le relâchement de ces facteurs pouvait aussi être induit par stimulation avec les cellules WEHI 164. Les surnageants de cellules Kurloff stimulées 18 heures avec le TPA et l'ionomydne étaient très cytotoxiques contre les cellules cibles WEHI 164 mais étaient inactifs contre les cellules cibles TNF-résistantes, P815. La cytotoxicité de ces surnageants était presque totalement inhibée en présence d'anticorps anti-TNFa murins. Au contraire, les surnageants de cellules Kurloff stimulées pendant seulement 4 heures n'ont démontré aucune activté TNF-like contre les cellules L-929 et n'étaient pas non plus cytoxiques contre les cellules WEHI 164. L'activité cytolytique des cellules Kurloff contre les cellules WEHI 164 était partiellement bloquée par le monensin dans l'essai de 4 heures et de 18 heures, quoique l'effet inhibiteur observé était plus marqué dans l'essai de 4 heures. L'ensemble de ces résultats suggère que les cellules Kurloff jouent un rôle primordial dans la défense anti-tumorale du cobaye en utilisant différents mécanismes lytiques

EpCAM immunotherapy versus specific targeted delivery of drugs

The epithelial cell adhesion molecule (EpCAM), or CD326, was one of the first cancer associated biomarkers to be discovered. In the last forty years, this biomarker has been investigated for use in personalized cancer therapy, with the first monoclonal antibody, edrecolomab, being trialled in humans more than thirty years ago. Since then, several other monoclonal antibodies have been raised to EpCAM and tested in clinical trials. However, while monoclonal antibody therapy has been investigated against EpCAM for almost 40 years as primary or adjuvant therapy, it has not shown as much promise as initially heralded. In this review, we look at the reasons why and consider alternative targeting options, such as aptamers, to turn this almost ubiquitously expressed epithelial cancer biomarker into a viable target for future personalized therapy

Effect of the intermediate velocity emissions on the quasi-projectile properties for the Ar+Ni system at 95 A.MeV

The quasi-projectile (QP) properties are investigated in the Ar+Ni collisions at 95 A.MeV taking into account the intermediate velocity emission. Indeed, in this reaction, between 52 and 95 A.MeV bombarding energies, the number of particles emitted in the intermediate velocity region is related to the overlap volume between projectile and target. Mean transverse energies of these particles are found particularly high. In this context, the mass of the QP decreases linearly with the impact parameter from peripheral to central collisions whereas its excitation energy increases up to 8 A.MeV. These results are compared to previous analyses assuming a pure binary scenario

Cancer cell CCL5 mediates bone marrow independent angiogenesis in breast cancer

It has recently been suggested that the chemokine receptor (CCR5) is required for bone marrow (BM) derived endothelial progenitor cell (EPC) mediated angiogenesis. Here we show that suppression of either cancer cell produced CCL5, or host CCR5 leads to distinctive vascular and tumor growth defects in breast cancer. Surprisingly, CCR5 restoration in the BM alone was not sufficient to rescue the wild type phenotype, suggesting that impaired tumor growth associated with inhibiting CCL5/CCR5 is not due to defects in EPC biology. Instead, to promote angiogenesis cancer cell CCL5 may signal directly to endothelium in the tumor-stroma. In support of this hypothesis, we have also shown: (i) that endothelial cell CCR5 levels increases in response to tumor-conditioned media; (ii) that the amount of CCR5+ tumor vasculature correlates with invasive grade; and (iii) that inhibition of CCL5/CCR5 signaling impairs endothelial cell migration, associated with a decrease in activation of mTOR/AKT pathway members. Finally, we show that treatment with CCR5 antagonist results in less vasculature, impaired tumor growth, reduced metastases and improved survival. Taken as a whole, this work demonstrates that directly inhibiting CCR5 expressing vasculature constitutes a novel strategy for inhibiting angiogenesis and blocking metastatic progression in breast cancer

Estrogen receptor alpha drives proliferation in PTEN-deficient prostate carcinoma by stimulating survival signaling, MYC expression and altering glucose sensitivity

While high doses of estrogen, in combination with androgens, can initiate prostate cancer (PCa) via activation of the estrogen receptor α (ERα), the role of ERα in PCa cells within established tumors is largely unknown. Here we show that expression of ERα is increased in high grade human PCa. Similarly, ERα is elevated in mouse models of aggressive PCa driven by MYC overexpression or deletion of PTEN. Within the prostate of PTEN-deficient mice, there is a progressive pattern of ERα expression: low in benign glands, moderate in tumors within the dorsal, lateral and ventral lobes, and high in tumors within the anterior prostate. This expression significantly correlates with the proliferation marker Ki67. Furthermore, in vitro knockdown of ERα in cells derived from PTEN-deficient tumors causes a significant and sustained decrease in proliferation. Depletion of ERα also reduces the activity of the PI3K and MAPK pathways, both downstream targets of non-genomic ERα action. Finally, ERα knockdown reduces the levels of the MYC protein and lowers the sensitivity of cellular proliferation to glucose withdrawal, which correlates with decreased expression of the glucose transporter GLUT1. Collectively, these results demonstrate that ERα orchestrates proliferation and metabolism to promote the neoplastic growth of PCa cells

Tumor-specific expression of αvβ3 integrin promotes spontaneous metastasis of breast cancer to bone

INTRODUCTION: Studies in xenograft models and experimental models of metastasis have implicated several β3 integrin-expressing cell populations, including endothelium, platelets and osteoclasts, in breast tumor progression. Since orthotopic human xenograft models of breast cancer are poorly metastatic to bone and experimental models bypass the formation of a primary tumor, however, the precise contribution of tumor-specific αvβ3 to the spontaneous metastasis of breast tumors from the mammary gland to bone remains unclear. METHODS: We used a syngeneic orthotopic model of spontaneous breast cancer metastasis to test whether exogenous expression of αvβ3 in a mammary carcinoma line (66cl4) that metastasizes to the lung, but not to bone, was sufficient to promote its spontaneous metastasis to bone from the mammary gland. The tumor burden in the spine and the lung following inoculation of αvβ3-expressing 66cl4 (66cl4beta3) tumor cells or control 66cl4pBabe into the mammary gland was analyzed by real-time quantitative PCR. The ability of these cells to grow and form osteolytic lesions in bone was determined by histology and tartrate-resistant acid phosphatase staining of bone sections following intratibial injection of tumor cells. The adhesive, migratory and invasive properties of 66cl4pBabe and 66cl4beta3 cells were evaluated in standard in vitro assays. RESULTS: The 66cl4beta3 tumors showed a 20-fold increase in metastatic burden in the spine compared with 66cl4pBabe. A similar trend in lung metastasis was observed. αvβ3 did not increase the proliferation of 66cl4 cells in vitro or in the mammary gland in vivo. Similarly, αvβ3 is not required for the proliferation of 66cl4 cells in bone as both 66cl4pBabe and 66cl4beta3 proliferated to the same extent when injected directly into the tibia. 66cl4beta3 tumor growth in the tibia, however, increased osteoclast recruitment and bone resorption compared with 66cl4 tumors. Moreover, αvβ3 increased 66cl4 tumor cell adhesion and αvβ3-dependent haptotactic migration towards bone matrix proteins, as well as their chemotactic response to bone-derived soluble factors in vitro. CONCLUSION: These results demonstrate for the first time that tumor-specific αvβ3 contributes to spontaneous metastasis of breast tumors to bone and suggest a critical role for this receptor in mediating chemotactic and haptotactic migration towards bone factors

[10]-gingerol induces apoptosis and inhibits metastatic dissemination of triple negative breast cancer in vivo

There is increasing interest in the use of non-toxic natural products for the treatment of various pathologies, including cancer. In particular, biologically active constituents of the ginger oleoresin (Zingiber officinale Roscoe) have been shown to mediate anti-tumour activity and to contribute to the anti-inflammatory, antioxidant, antimicrobial, and antiemetic properties of ginger. Here we report on the inhibitory properties of [10]-gingerol against metastatic triple negative breast cancer (TNBC) in vitro and in vivo. We show that [10]-gingerol concentration-dependently induces apoptotic death in mouse and human TNBC cell lines in vitro. In addition, [10]-gingerol is well tolerated in vivo, induces a marked increase in caspase-3 activation and inhibits orthotopic tumour growth in a syngeneic mouse model of spontaneous breast cancer metastasis. Importantly, using both spontaneous and experimental metastasis assays, we show for the first time that [10]-gingerol significantly inhibits metastasis to multiple organs including lung, bone and brain. Remarkably, inhibition of brain metastasis was observed even when treatment was initiated after surgical removal of the primary tumour. Taken together, these results indicate that [10]-gingerol may be a safe and useful complementary therapy for the treatment of metastatic breast cancer and warrant further investigation of its efficacy, either alone or in combination with standard systemic therapies, in pre-clinical models of metastatic breast cancer and in patients

Investigating metastasis using in vitro platforms

The complexity of the metastatic cascade has led to the development of a plethora of 2- and 3-dimensional in vitro assays to model the various steps of metastasis under a more controlled environment. These assays have been invaluable in cancer research not only as tools to delineate the molecular events that underpin metastasis but also to enable drug screens and validation of therapeutic targets. Here we review the advantages and limitations of current in vitro platforms used to investigate metastasis. In light of the overwhelming evidence showing that 3-dimentional culture systems better mimic the tumor microenvironment and therapeutic response in vivo, recent advances made toward the development of 3-dimensional culture systems and their applications are discussed in more detail. Relevant information on protocols and resources available to support scientists with an interest in metastasis research is also provided

Investigating metastasis using in vitro platforms

The complexity of the metastatic cascade has led to the development of a plethora of 2- and 3-dimensional in vitro assays to model the various steps of metastasis under a more controlled environment. These assays have been invaluable in cancer research not only as tools to delineate the molecular events that underpin metastasis but also to enable drug screens and validation of therapeutic targets. Here we review the advantages and limitations of current in vitro platforms used to investigate metastasis. In light of the overwhelming evidence showing that 3-dimentional culture systems better mimic the tumor microenvironment and therapeutic response in vivo, recent advances made toward the development of 3-dimensional culture systems and their applications are discussed in more detail. Relevant information on protocols and resources available to support scientists with an interest in metastasis research is also provided