Fluence plays a critical role on the subsequent distribution of chemotherapy and tumor growth delay in murine mesothelioma xenografts pre-treated by photodynamic therapy.

BACKGROUND: The pre-conditioning of tumor vessels by low-dose photodynamic therapy (L-PDT) was shown to enhance the distribution of chemotherapy in different tumor types. However, how light dose affects drug distribution and tumor response is unknown. Here we determined the effect of L-PDT fluence on vascular transport in human mesothelioma xenografts. The best L-PDT conditions regarding drug transport were then combined with Lipoplatin(®) to determine tumor response. METHODS: Nude mice bearing dorsal skinfold chambers were implanted with H-Meso1 cells. Tumors were treated by Visudyne(®) -mediated photodynamic therapy with 100 mW/cm(2) fluence rate and a variable fluence (5, 10, 30, and 50 J/cm(2) ). FITC-Dextran (FITC-D) distribution was assessed in real time in tumor and normal tissues. Tumor response was then determined with best L-PDT conditions combined to Lipoplatin(®) and compared to controls in luciferase expressing H-Meso1 tumors by size and whole body bioluminescence assessment (n = 7/group). RESULTS: Tumor uptake of FITC-D following L-PDT was significantly enhanced by 10-fold in the 10 J/cm(2) but not in the 5, 30, and 50 J/cm(2) groups compared to controls. Normal surrounding tissue uptake of FITC-D following L-PDT was significantly enhanced in the 30 J/cm(2) and 50 J/cm(2) groups compared to controls. Altogether, the FITC-D tumor to normal tissue ratio was significantly higher in the 10 J/cm(2) group compared others. Tumor growth was significantly delayed in animals treated by 10 J/cm2-L-PDT combined to Lipoplatin(®) compared to controls. CONCLUSIONS: Fluence of L-PDT is critical for the optimal distribution and effect of subsequently administered chemotherapy. These findings have an importance for the clinical translation of the vascular L-PDT concept in the clinics.

Transportin regulates nuclear import of CD44.

CD44 is a facultative cell surface proteoglycan that serves as the principal cell surface receptor for hyaluronan (HA). Studies have shown that in addition to participating in numerous signaling pathways, CD44 becomes internalized upon engagement by ligand and that a portion of its intracellular domain can translocate to the nucleus where it is believed to play a functional role in cell proliferation and survival. However, the mechanisms whereby fragments of CD44 enter the nucleus have not been elucidated. Here we show that CD44 interacts with two import receptors of the importin ß superfamily, importin ß itself and transportin. Inhibition of importin ß-dependent transport failed to block CD44 accumulation in the nucleus. By contrast, inhibition of the transportin-dependent pathway abrogated CD44 import. Mutagenesis of the intracellular domain of CD44 revealed that the 20 membrane-proximal residues contain sequences required for transportin-mediated nuclear transport. Our observations provide evidence that CD44 interacts with importin family members and identify the transportin-dependent pathway as the mechanism whereby full-length CD44 enters the nucleus.

Clinical, biometric and structural evaluation of the long-term effects of a topical treatment with ascorbic acid and madecassoside in photoaged human skin.

Skin ageing is a complex process determined by the genetic endowment of individual and environmental factors, such as sun exposure. The effects of skin ageing are mostly encountered in the superficial dermis and in the epidermis. We have previously demonstrated in vivo the beneficial effect of a topically applied formula of 5% vitamin C in the treatment of skin ageing. Another active compound, madecassoside extracted from Centella asiatica, known to induce collagen expression and/or to modulate inflammatory mediators, might thus prevent and correct some signs of ageing. A randomized double-blind study was carried out on photoaged skin of 20 female volunteers to investigate the effects of topically applied 5% vitamin C and 0.1% madecassoside on the clinical, biophysical and structural skin properties. After 6 months of treatment, we observed a significant improvement of the clinical score for deep and superficial wrinkles, suppleness, firmness, roughness and skin hydration. These results were corroborated by measurements of skin elasticity and semi-quantitative histological assessment of the elastic fibre network in the papillary dermis. Two-thirds of the subjects showed an improvement. The re-appearance of a normally structured elastic fibre network was observed. Our results revealed a functional and structural remodelling of chronically sun-damaged skin.

Sensitive and frequent identification of high avidity neo-epitope specific CD8 + T cells in immunotherapy-naive ovarian cancer.

Immunotherapy directed against private tumor neo-antigens derived from non-synonymous somatic mutations is a promising strategy of personalized cancer immunotherapy. However, feasibility in low mutational load tumor types remains unknown. Comprehensive and deep analysis of circulating and tumor-infiltrating lymphocytes (TILs) for neo-epitope specific CD8+ T cells has allowed prompt identification of oligoclonal and polyfunctional such cells from most immunotherapy-naive patients with advanced epithelial ovarian cancer studied. Neo-epitope recognition is discordant between circulating T cells and TILs, and is more likely to be found among TILs, which display higher functional avidity and unique TCRs with higher predicted affinity than their blood counterparts. Our results imply that identification of neo-epitope specific CD8+ T cells is achievable even in tumors with relatively low number of somatic mutations, and neo-epitope validation in TILs extends opportunities for mutanome-based personalized immunotherapies to such tumors.

Desmosome-binding antibody KM48 recognises an extracellular antigen different from desmosomal cadherins Dsg 1-3 and Dsc 1-3.

Desmosomes are the most prominent and mechanically important epidermal intercellular junctions. Transmembrane proteins of desmosomes, desmogleins and desmocollins, are responsible for extracellular binding and, thus, are important for interkeratinocyte cohesion. We show here, using three different approaches, that the extracellular "cores" of epidermal desmosomes contain a highly glycosylated antigen, different from desmosomal cadherins. This protein, recognised by KM48 monoclonal antibody, is likely to be involved in the processes of keratinocyte differentiation, desmosome turnover and epidermal cohesion.

Myeloid-derived suppressor cells are implicated in regulating permissiveness for tumor metastasis during mouse gestation.

Metastasis depends on the ability of tumor cells to establish a relationship with the newly seeded tissue that is conducive to their survival and proliferation. However, the factors that render tissues permissive for metastatic tumor growth have yet to be fully elucidated. Breast tumors arising during pregnancy display early metastatic proclivity, raising the possibility that pregnancy may constitute a physiological condition of permissiveness for tumor dissemination. Here we have shown that during murine gestation, metastasis is enhanced regardless of tumor type, and that decreased NK cell activity is responsible for the observed increase in experimental metastasis. Gene expression changes in pregnant mouse lung and liver were shown to be similar to those detected in premetastatic sites and indicative of myeloid cell infiltration. Indeed, myeloid-derived suppressor cells (MDSCs) accumulated in pregnant mice and exerted an inhibitory effect on NK cell activity, providing a candidate mechanism for the enhanced metastatic tumor growth observed in gestant mice. Although the functions of MDSCs are not yet understood in the context of pregnancy, our observations suggest that they may represent a shared mechanism of immune suppression occurring during gestation and tumor growth.

EZH2 is essential for glioblastoma cancer stem cell maintenance.

Overexpression of the polycomb group protein enhancer of zeste homologue 2 (EZH2) occurs in diverse malignancies, including prostate cancer, breast cancer, and glioblastoma multiforme (GBM). Based on its ability to modulate transcription of key genes implicated in cell cycle control, DNA repair, and cell differentiation, EZH2 is believed to play a crucial role in tissue-specific stem cell maintenance and tumor development. Here, we show that targeted pharmacologic disruption of EZH2 by the S-adenosylhomocysteine hydrolase inhibitor 3-deazaneplanocin A (DZNep), or its specific downregulation by short hairpin RNA (shRNA), strongly impairs GBM cancer stem cell (CSC) self-renewal in vitro and tumor-initiating capacity in vivo. Using genome-wide expression analysis of DZNep-treated GBM CSCs, we found the expression of c-myc, recently reported to be essential for GBM CSCs, to be strongly repressed upon EZH2 depletion. Specific shRNA-mediated downregulation of EZH2 in combination with chromatin immunoprecipitation experiments revealed that c-myc is a direct target of EZH2 in GBM CSCs. Taken together, our observations provide evidence that direct transcriptional regulation of c-myc by EZH2 may constitute a novel mechanism underlying GBM CSC maintenance and suggest that EZH2 may be a valuable new therapeutic target for GBM management.

Tumor-host interactions: the role of inflammation.

It is well established that interactions between tumor cells and the host tissue stroma play a key role in determining whether and how any given solid malignancy will develop. In most cases, tumor cells hijack stromal cell functions for their own benefit and ultimately dictate the rules of engagement to the host tissue microenvironment. However, the contribution of the different stromal cell components to tumor growth remains to be clarified. Because most solid tumors are accompanied by a local inflammatory response, it has long been thought that inflammation and carcinogenesis are related. If formal proof that cancer can be initiated by inflammation in the absence of exogenous carcinogens is still lacking, there is abundant evidence that the inflammatory response can play a central role in modulating tumor growth and progression. This review will discuss some of the mechanisms whereby inflammation can both enhance and inhibit tumor growth.