Nanobody-based retargeting of an oncolytic herpesvirus for eliminating CXCR4+ GBM cells: A proof of principle.

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults, which remains difficult to cure. The very high recurrence rate has been partly attributed to the presence of GBM stem-like cells (GSCs) within the tumors, which have been associated with elevated chemokine receptor 4 (CXCR4) expression. CXCR4 is frequently overexpressed in cancer tissues, including GBM, and usually correlates with a poor prognosis. We have created a CXCR4-retargeted oncolytic herpesvirus (oHSV) by insertion of an anti-human CXCR4 nanobody in glycoprotein D of an attenuated HSV-1 (ΔICP34.5, ΔICP6, and ΔICP47), thereby describing a proof of principle for the use of nanobodies to target oHSVs toward specific cellular entities. Moreover, this virus has been armed with a transgene expressing a soluble form of TRAIL to trigger apoptosis. In vitro, this oHSV infects U87MG CXCR4+ and patient-derived GSCs in a CXCR4-dependent manner and, when armed, triggers apoptosis. In a U87MG CXCR4+ orthotopic xenograft mouse model, this oHSV slows down tumor growth and significantly improves mice survival. Customizing oHSVs with diverse nanobodies for targeting multiple proteins appears as an interesting approach for tackling the heterogeneity of GBM, especially GSCs. Altogether, our study must be considered as a proof of principle and a first step toward personalized GBM virotherapies to complement current treatments.

PD-L1 Expression Fluctuates Concurrently with Cyclin D in Glioblastoma Cells.

Despite Glioblastoma (GBM) frequently expressing programmed cell death ligand-1 (PD-L1), treatment with anti-programmed cell death-1 (PD1) has not yielded brilliant results. Intratumor variability of PD-L1 can impact determination accuracy. A previous study on mouse embryonic fibroblasts (MEFs) reported a role for cyclin-D in control of PD-L1 expression. Because tumor-cell growth within a cancer is highly heterogeneous, we looked at whether PD-L1 and its cochaperone FKBP51s were influenced by cell proliferation, using U251 and SF767 GBM-cell-lines. PD-L1 was measured by Western blot, flow cytometry, confocal-microscopy, quantitative PCR (qPCR), CCND1 by qPCR, FKBP51s by Western blot and confocal-microscopy. Chromatin-Immunoprecipitation assay (xChIp) served to assess the DNA-binding of FKBP51 isoforms. In the course of cell culture, PD-L1 appeared to increase concomitantly to cyclin-D on G1/S transition, to decrease during exponential cell growth progressively. We calculated a correlation between CCND1 and PD-L1 gene expression levels. In the temporal window of PD-L1 and CCND1 peak, FKBP51s localized in ER. When cyclin-D declined, FKBP51s went nuclear. XChIp showed that FKBP51s binds CCND1 gene in a closed-chromatin configuration. Our finding suggests that the dynamism of PD-L1 expression in GBM follows cyclin-D fluctuation and raises the hypothesis that FKBP51s might participate in the events that govern cyclin-D oscillation.

Outcomes of three different new generation transcatheter aortic valve prostheses.

AIMS: To evaluate outcomes of transfemoral transcatheter aortic valve implantation (TF-TAVI) using three different new-generation devices. BACKGROUND: Although new generation transcatheter aortic valves (TAVs) have demonstrated to improve procedural outcomes, to date few head-to-head comparisons are available among these devices. METHODS: This is a single center, retrospective study. From September 2014 to February 2018, 389 patients underwent elective TF-TAVI for native, severe aortic stenosis using a new-generation transcatheter aortic valve (TAV) with a preprocedural multi-detector computed tomography assessment. Among these, 346 patients received an Edwards SAPIEN 3 (n = 134), Medtronic Evolut R (n = 111), or Boston ACURATE neo (n = 101) prosthesis. Differences in baseline clinical characteristics between groups were accounted using the propensity score weighting method. RESULTS: The mean age for the entire study cohort was 81.4 ± 5.2 years while the Society of Thoracic Surgery predicted risk of mortality was 4.0 ± 2.5%. After propensity score weighting adjustment, TAVs did not differently impact on 30-day all-cause and cardiovascular mortality. Evolut R device showed an increased risk of permanent pacemaker implantation (PPI) after the procedure (8.3% for SAPIEN 3 vs. 16.7% for Evolut R vs. 2.1% for ACURATE neo, p < .05). At 30 days, patients treated with SAPIEN 3 valve showed a higher mean transvalvular gradient (9.7 ± 7.5 mmHg vs. 6.1 ± 2.4 mmHg vs. 8.4 ± 3.5 mmHg for SAPIEN 3, Evolut R, and ACURATE neo, respectively, p < .01) and a lower rate of more-than-trace paravalvular regurgitation (PVR) (18.8 vs. 47.9 vs. 45.8%, for SAPIEN 3, Evolut R, and ACURATE neo, respectively, p < .01). At 1 year, SAPIEN 3, Evolut R, and ACURATE neo TAVs showed excellent and comparable outcomes with no difference in terms of freedom from major adverse cardiovascular and cerebrovascular event (MACCE) (plog-rank = 0.534). CONCLUSIONS: TAVI using new-generation prostheses was associated with high device success (97.0% vs. 92.8% vs. 95.0% for SAPIEN 3, Evolut R and ACURATE neo, respectively) and low complications rates up to 1 year. Evolut R valve was associated with a higher rate of PPI whereas SAPIEN 3 valve was associated with a higher mean transvalvular gradient and lower rate of more-than-trace PVR. At 1-year, MACCE rates were similar among the three groups.

Manipulation of the Immune System for Cancer Defeat: A Focus on the T Cell Inhibitory Checkpoint Molecules.

The immune system actively counteracts the tumorigenesis process; a breakout of the immune system function, or its ability to recognize transformed cells, can favor cancer development. Cancer becomes able to escape from immune system control by using multiple mechanisms, which are only in part known at a cellular and molecular level. Among these mechanisms, in the last decade, the role played by the so-called "inhibitory immune checkpoints" is emerging as pivotal in preventing the tumor attack by the immune system. Physiologically, the inhibitory immune checkpoints work to maintain the self-tolerance and attenuate the tissue injury caused by pathogenic infections. Cancer cell exploits such immune-inhibitory molecules to contrast the immune intervention and induce tumor tolerance. Molecular agents that target these checkpoints represent the new frontier for cancer treatment. Despite the heterogeneity and multiplicity of molecular alterations among the tumors, the immune checkpoint targeted therapy has been shown to be helpful in selected and even histologically different types of cancer, and are currently being adopted against an increasing variety of tumors. The most frequently used is the moAb-based immunotherapy that targets the Programmed Cell Death 1 protein (PD-1), the PD-1 Ligand (PD-L1) or the cytotoxic T lymphocyte antigen-4 (CTLA4). However, new therapeutic approaches are currently in development, along with the discovery of new immune checkpoints exploited by the cancer cell. This article aims to review the inhibitory checkpoints, which are known up to now, along with the mechanisms of cancer immunoediting. An outline of the immune checkpoint targeting approaches, also including combined immunotherapies and the existing trials, is also provided. Notwithstanding the great efforts devoted by researchers in the field of biomarkers of response, to date, no validated FDA-approved immunological biomarkers exist for cancer patients. We highlight relevant studies on predictive biomarkers and attempt to discuss the challenges in this field, due to the complex and largely unknown dynamic mechanisms that drive the tumor immune tolerance.

Cell stemness, epithelial-to-mesenchymal transition, and immunoevasion: Intertwined aspects in cancer metastasis.

Recent advances in tumor immunology, fostered by dramatic outcomes with cancer immunotherapy, have opened new scenarios in cancer metastasis. The cancer stemness/mesenchymal phenotype and an excess of immune suppressive signals are emerging as Intertwined aspects of human tumors. This review examines recent studies that explored the mechanistic links between cancer cell stemness and immunoevasion, and the evidence points to these key events in cancer metastasis as two sides of the same coin. This review also covers the mechanisms involved in tumor expression of programmed cell death ligand 1 (PD-L1), a major factor exploited by human neoplasias to suppress immune control. We highlight the convergence of mesenchymal traits and PD-L1 expression and examine the functions of this immune inhibitory molecule, which confers cancer cell resistance and aggressiveness.

The splicing FK506-binding protein-51 isoform plays a role in glioblastoma resistance through programmed cell death ligand-1 expression regulation.

Gliomas aberrantly express programmed cell death ligand-1 (PD-L1), which has a pivotal role in immunoevasion. The splicing isoform of FKBP5, termed FKBP51s, is a PD-L1 foldase, assisting the immune checkpoint molecule in maturation and expression on the plasma membrane. The concept that PD-L1 supports tumor-intrinsic properties is increasingly emerging. The aim of the present work was to confirm the pro-tumoral effect of PD-L1 on human glioma cell survival, stemness capacity and resistance, and to address the issue of whether, by targeting its foldase either chemically or by silencing, the aggressive tumor features could be attenuated. PD-L1-depleted glioma cells have a reduced threshold for apoptosis, while PD-L1 forced expression increases resistance. Similar results were obtained with FKBP51s modulation. The ability of PD-L1 to counteract cell death was hampered by FKBP51s silencing. PD-L1 expression was particularly high in glioma cells with a cancer-stem-cell profile. Moreover, PD-L1 sustained the spheroid formation capability of glioma cells. Targeting of FKBP51s by small-interfering RNA (siRNA) or the specific inhibitor SAFit2, reduced the number of formed spheroids, along with PD-L1 expression. Finally, in an orthotopic mouse model of glioblastoma, daily treatment with SAFit2 significantly reduced tumor PD-L1 expression, and tumor growth. In treated mice, caspase-3 activation and reduced vimentin expression were observed in excised tumors. In conclusion, targeting of FKBP51s hampers PD-L1 and its pro-tumoral properties, thereby affecting the self-renewal and growth capacities of glioblastoma cells in vitro and in vivo.

Transcatheter Aortic Valve Replacement in Oncology Patients With Severe Aortic Stenosis.

OBJECTIVES: The authors sought to collect data on contemporary practice and outcome of transcatheter aortic valve replacement (TAVR) in oncology patients with severe aortic stenosis (AS). BACKGROUND: Oncology patients with severe AS are often denied valve replacement. TAVR may be an emerging treatment option. METHODS: A worldwide registry was designed to collect data on patients who undergo TAVR while having active malignancy. Data from 222 cancer patients from 18 TAVR centers were compared versus 2,522 "no-cancer" patients from 5 participating centers. Propensity-score matching was performed to further adjust for bias. RESULTS: Cancer patients' age was 78.8 ± 7.5 years, STS score 4.9 ± 3.4%, 62% men. Most frequent cancers were gastrointestinal (22%), prostate (16%), breast (15%), hematologic (15%), and lung (11%). At the time of TAVR, 40% had stage 4 cancer. Periprocedural complications were comparable between the groups. Although 30-day mortality was similar, 1-year mortality was higher in cancer patients (15% vs. 9%; p < 0.001); one-half of the deaths were due to neoplasm. Among patients who survived 1 year after the TAVR, one-third were in remission/cured from cancer. Progressive malignancy (stage III to IV) was a strong mortality predictor (hazard ratio: 2.37; 95% confidence interval: 1.74 to 3.23; p < 0.001), whereas stage I to II cancer was not associated with higher mortality compared with no-cancer patients. CONCLUSIONS: TAVR in cancer patients is associated with similar short-term but worse long-term prognosis compared with patients without cancer. Among this cohort, mortality is largely driven by cancer, and progressive malignancy is a strong mortality predictor. Importantly, 85% of the patients were alive at 1 year, one-third were in remission/cured from cancer. (Outcomes of Transcatheter Aortic Valve Implantation in Oncology Patients With Severe Aortic Stenosis [TOP-AS]; NCT03181997).

TRAF2 and FKBP51 as possible markers for identification of suitable melanoma tumors for tumor necrosis factor-α inhibition.

Tumor necrosis factor-α (TNF-α) is a pleiotropic cytokine, whose role in melanoma is controversial. Although high-dose TNF-α is approved for the treatment of patients with in transit-metastatic melanoma confined to the limb, diverse preclinical models of melanoma have shown that TNF-α can induce cell invasion. Biomarkers that can differentiate between the dual role of TNF-α are needed. TRAF2 is critical to TNF receptor-induced activation of nuclear factor-κB (NF-κB), allowing shifting from death to survival-signaling cascades. The large immunophilin FKBP51 acts as a scaffold and catalyst in the IκB kinase complex assembly and activation. Here, using microscopy and an electrophoretic mobility-shift assay, we provide further evidence in support of the essential role of FKBP51 in sustaining the TNF-α NF-κB signaling in melanoma. Through the cross-linking reaction with the chemical linker disuccinimidyl glutarate, we show that a direct interaction occurs between FKBP51 and TRAF2 in melanoma cells. Immunohistochemistry of tumor samples from 24 patients with cutaneous melanomas showed a correlation between the expressions of the two proteins. Given the association of FKBP51 and TRAF2 with TNF-α-induced NF-κB signaling and their correlation in tumor samples, we propose that the two proteins can be exploited as useful markers for the identification of those melanoma tumors that can benefit from TNF-α inhibition. Future studies will address this hypothesis.

Incidence of Long-Term Structural Valve Dysfunction and Bioprosthetic Valve Failure After Transcatheter Aortic Valve Replacement.

Background Long-term data on durability of currently available transcatheter heart valves are sparse. We sought to assess the incidence of long-term (8-year) structural valve dysfunction and bioprosthetic valve failure in a cohort of patients with transcatheter aortic valve replacement ( TAVR ) who reached at least 5-year follow-up. Methods and Results Consecutive patients with at least 5-year follow-up available undergoing TAVR from June 4, 2007 to March 30, 2012 were included. Structural valve dysfunction and bioprosthetic valve failure were defined according to newly standardized European Association of Percutaneous Cardiovascular Interventions/ European Society of Cardiology/European Association for Cardio-Thoracic Surgery criteria and reported as cumulative incidence function to account for the competing risk of death. A total of 288 consecutive patients with a mean age of 80.7±5.3 years and with a mean Society of Thoracic Surgery mortality score of 8.1±5.1% were analyzed. Survival rate at 8 years was 29.8%. Mean pressure gradients decreased from 53.3±15.9 mm Hg (pre- TAVR ) to 10.5±4.5 mm Hg (in-hospital post- TAVR ) ( P<0.001). There was a small, not significant, increase in the transaortic gradient throughout follow-up. Bioprosthetic valve failure was observed in a total of 11 patients (8-year cumulative incidence function: 4.51%; 95% confidence interval , 1.95%-8.76%). Severe and moderate structural valve dysfunctions were reported in 7 patients (8-year cumulative incidence function: 2.39%; 95% confidence interval, 0.77%-5.71%) and 13 patients (8-year cumulative incidence function: 5.87%; 95% confidence interval , 3.06%-9.96%), respectively. Aortic valve reintervention (redo TAVR ) was successfully performed in 2 patients (0.7%) presenting with symptomatic severe restenosis and intraprosthetic regurgitation subsequent to endocarditis. Conclusions In an aged population of patients with symptomatic severe aortic stenosis treated with first-generation bioprostheses, TAVR was associated with a survival rate of 30% but low rates of bioprosthetic valve failure and structural valve dysfunction at 8 years.

A regulatory role for the co-chaperone FKBP51s in PD-L1 expression in glioma.

BACKGROUND: FKBP51 is a co-chaperone with isomerase activity, abundantly expressed in glioma. We previously identified a spliced isoform (FKBP51s) and highlighted a role for this protein in the upregulation of Programmed Death Ligand 1 (PD-L1) expression in melanoma. Because gliomas can express PD-L1 causing a defective host anti-tumoral immunity, we investigated whether FKBP51s was expressed in glioma and played a role in PD-L1 regulation in this tumour. METHODS: We used D54 and U251 glioblastoma cell lines that constitutively expressed PD-L1. FKBP51s was measured by immunoblot, flow cytometry and microscopy. In patient tumours, IHC and qPCR were used to measure protein and mRNA levels respectively. FKBP51s depletion was achieved by siRNAs, and its enzymatic function was inhibited using selective inhibitors (SAFit). We investigated protein maturation using N-glycosidase and cell fractionation approaches. RESULTS: FKBP51s was expressed at high levels in glioma cells. Glycosylated-PD-L1 was increased and reduced by FKBP51s overexpression or silencing, respectively. Naïve PD-L1 was found in the endoplasmic reticulum (ER) of glioma cells complexed with FKBP51s, whereas the glycosylated form was measured in the Golgi apparatus. SAFit reduced PD-L1 levels (constitutively expressed and ionizing radiation-induced). SAFit reduced cell death of PBMC co-cultured with glioma. CONCLUSIONS: Here we addressed the mechanism of post-translational regulation of PD-L1 protein in glioma. FKBP51s upregulated PD-L1 expression on the plasma membrane by catalysing the protein folding required for subsequent glycosylation. Inhibition of FKBP51s isomerase activity by SAFit decreased PD-L1 levels. These findings suggest that FKBP51s is a potential target of immunomodulatory strategies for glioblastoma treatment.

Optimized Screening of Coronary Artery Disease With Invasive Coronary Angiography and Ad Hoc Percutaneous Coronary Intervention During Transcatheter Aortic Valve Replacement.

BACKGROUND: We sought to describe an optimized approach to coronary artery disease (CAD) screening and management in patients undergoing transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS: When invasive coronary angiography showed CAD, the treatment strategy and completeness of revascularization was determined based on coronary anatomy. TAVR was performed in the same setting if percutaneous coronary intervention (PCI) was uncomplicated; otherwise TAVR was postponed. A total of 604 patients undergoing CAD screening at the time of TAVR procedure were prospectively included in this study. Severe CAD was found in 136 patients (22.5%). Among patients with severe CAD, 53 patients (8.8%) underwent uncomplicated PCI. After PCI, TAVR was postponed in 2 patients (0.3%). In 83 patients (13.8%), coronary angiography showed severe CAD that was left untreated. After TAVR, all-cause and cardiovascular 30-day mortality rates were 2.4% and 1.4%, respectively. Disabling stroke, myocardial infarction, and life-threatening bleeding occurred in 0.5%, 0.8%, and 4.0% of patients, respectively. Acute kidney injury II or III rate was 3.3%. At 2 years, all-cause mortality rate was 14.1%. Disabling stroke and myocardial infarction occurred in 2.5% and 1.8% of patients, respectively. Patients undergoing TAVR and PCI in the same session had similar rate of the composite of death, disabling stroke, and myocardial infarction when compared with patients without CAD, and patients with severe CAD left untreated (TAVR+PCI: 10.4%; severe CAD left untreated: 15.4%; no-CAD: 14.8%; P=0.765). CONCLUSIONS: In patients undergoing TAVR, screening of CAD with invasive coronary angiography and ad hoc PCI during TAVR is feasible and was not associated with increased periprocedural risks. PCI followed by TAVR in the same session had similar outcomes than TAVR in which PCI was not performed.

FKBP51s signature in peripheral blood mononuclear cells of melanoma patients as a possible predictive factor for immunotherapy.

The inhibitory immune checkpoint PD-L1/PD1 promotes the alternative splicing of the FKBP5 gene, resulting in increased expression of its variant 4 in the peripheral blood mononuclear cells of melanoma patients. The variant 4 transcript is translated into the truncated FKBP51s protein. Given the importance of co-inhibitory signalling in tumour immune escape, here we tested the potential for using FKBP51s expression to predict immunotherapy outcomes. To do this, we immunophenotyped PBMCs from 118 melanoma patients and 77 age- and sex-matched healthy controls. Blood samples were collected before patients underwent ipilimumab treatment. In 64 of the 118 patients, FKBP51s expression was also assessed in regulatory T cells (Tregs). We found that each PBMC subset analysed contained an FKBP51spos fraction, and that this fraction was greater in the melanoma patients than healthy controls. In CD4 T lymphocytes, the FKBP51sneg fraction was significantly impaired. Tregs count was increased in melanoma patients, which is in line with previous studies. Also, by analyses of FKBP51s in Tregs, we identified a subgroup of ipilimumab nonresponder patients (p = 0.002). In conclusion, FKBP51s-based immunophenotyping of melanoma patients revealed several profiles related to a negative immune regulatory control and identified an unknown Treg subset. These findings are likely to be useful in the selection of the patients that are candidate for immunotherapy.

Immunomodulatory pathways regulate expression of a spliced FKBP51 isoform in lymphocytes of melanoma patients.

FKBP51 (gene FKBP5) is an immunophilin capable of immunosuppression expressed in melanoma and lymphocytes. We found increased levels of a spliced FKBP5 variant in the PBMCs of 124 patients with melanoma. This variant encodes for an unknown isoform (FKBP51s). We hypothesized that FKBP51s resulted from tumour interaction with immune cells, through PDL-1/PD-1. To address this issue, we performed melanoma/PBMC cocultures. Furthermore, the immunohistochemistry of 76 melanoma specimens served to investigate whether FKBP51s stained tumour infiltrating lymphocytes. Our results showed that PBMCs expressed FKBP51s when cocultured with melanoma. Tumour PDL-1 knockdown or anti-PD-1 reduced FKBP51s expression in cocultured PBMCs. IHC showed a strong FKBP51s signal in tumour infiltrating lymphocytes, and lymphocytes of the invasion front of the tumour, along with melanoma PDL-1 expression. When overexpressed in melanoma, FKBP51s facilitated PDL-1 expression on the cell surface. In conclusion, our study shows that FKBP51s marks the PBMCs of patients with melanoma and is exploited by the tumour to immunomodulate through PDL-1.

Tirofiban induces VEGF production and stimulates migration and proliferation of endothelial cells.

Tirofiban is a fibrinogen receptor antagonist, generated using the tripeptide Arg-Gly-Asp (RGD) as a template. RGD activates integrin receptors and integrin-mediated signals are necessary for normal cells to promote survival and stimulate cell cycle progression. We investigated whether tirofiban activated growth-stimulatory signals in endothelium. For this study human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC) were used. Analysis of cell proliferation, by cell counts, showed that the number of endothelial cells doubled after 72 h of culture in the absence of tirofiban, while they were tripled and even quadrupled, in the presence of increasing doses of the drug. Moreover, tirofiban-stimulated cells had a greater ability to migrate through the transwell filters of Boyden chamber, compared to unstimulated cells. The scratch assay, which mimics cell migration during wound healing, showed that tirofiban stimulated HUVECs to migrate into the leading hedge of the scratch. Western blot showed that tirofiban increased the expression levels of VEGF and the downstream effectors Erk and cyclin D. An inhibitor of VEGFR2 counteracted tirofiban-induced-proliferation, suggesting a role for VEGF in such effect. Our study shows that tirofiban stimulates the migration and proliferation of endothelial cells suggesting that it can promote endothelial repair. Ex vivo cultures of arterial rings confirmed the growth stimulatory effect of tirofiban on endothelium. Thus, the benefits of tirofiban in those with acute coronary syndromes undergoing PTCA may be due to rapid endothelization of damaged vessel, besides antiplatelet effects.

FKBP51 increases the tumour-promoter potential of TGF-beta.

BACKGROUND: FKBP51 (FKBP5 Official Symbol) is a large molecular weight component of the family of FK506 binding proteins (FKBP). In recent years, research studies from our laboratory highlighted functions for FKBP51 in the control of apoptosis and melanoma progression. FKBP51 expression correlated with the invasiveness and aggressiveness of melanoma. Since a role for TGF-ß in the enhanced tumorigenic potential of melanoma cells is widely described, we hypothesized a cooperative effect between FKBP51 and TGF-ß in melanoma progression. METHODS: SAN and A375 melanoma cell lines were utilized for this study. Balb/c IL2γ NOD SCID served to assess the ability to colonize organs and metastasize of different cell lines, which was evaluated by in vivo imaging. Realtime PCR and western blot served for measurement of mRNA and protein expression, respectively. RESULTS: By comparing the metastatic potential of two melanoma cell lines, namely A375 and SAN, we confirmed that an increased capability to colonize murine organs was associated with increased levels of FKBP51. A375 melanoma cell line expressed FKBP51 mRNA levels 30-fold higher in comparison to the SAN mRNA level and appeared more aggressive than SAN melanoma cell line in an experimental metastasis model. In addition, A375 expressed, more abundantly than SAN, the TGF-ß and the pro angiogenic TGF-ß receptor type III (TßRIII) factors. FKBP51 silencing produced a reduction of TGF-ß and TßRIII gene expression in A375 cell line, in accordance with previous studies. We found that the inducing effect of TGF-ß on Sparc and Vimentin expression was impaired in condition of FKBP51 depletion, suggesting that FKBP51 is an important cofactor in the TGF-ß signal. Such a hypothesis was supported by co immunoprecipitation assays, showing that FKBP51 interacted with either Smad2,3 and p300. In normal melanocytes, FKBP51 potentiated the effect of TGF-ß on N-cadherin expression and conferred a mesenchymal-like morphology to such round-shaped cells. CONCLUSIONS: Overall, our findings show that FKBP51 enhances some pro oncogenic functions of TGF-ß, suggesting that FKBP51-overexpression may help melanoma to take advantage of the tumor promoting activities of the cytokine.