Michelina Festa

BAG3 protein is overexpressed in human glioblastoma and is a potential target for therapy.

Glioblastoma multiforme, which represents 80% of malignant gliomas, is characterized by aggressiveness and high recurrence rates. Despite therapeutic advances, patients with glioblastoma multiforme show a poor survival, and identification of novel markers and molecular targets for therapy is needed. A role for BAG3, a member of the BAG family of HSC/HSP70 co-chaperones, in promoting tumor cell growth in vivo has recently been described. We analyzed BAG3 levels by IHC in specimens from patients affected by brain tumors and we found that BAG3, although negative in normal brain tissues, was highly expressed in astrocytic tumors and increasingly expressed in more aggressive types of cancer; it was particularly high in glioblastomas. Down-regulating BAG3 both in vitro and in vivo in a rat glioblastoma model resulted in increased sensitivity to apoptosis, suggesting that BAG3 is a potential target for novel therapies. Finally, we determined that the underlying molecular mechanism requires the formation of a complex of BAG3, HSP70, and BAX that prevents BAX translocation to mitochondria, thus protecting tumor cells from apoptosis. Our data identify BAG3 as a potential marker of glial brain tumor sensitivity to therapy and thus also an attractive candidate for new molecular therapies.

BAG3 protein regulates cell survival in childhood acute lymphoblastic leukemia cells.

No abstract available.

The activity of hsp90|[alpha]| promoter is regulated by NF-|[kappa]|B transcription factors

Heat-shock proteins (HSP) 90 exert a relevant role in the survival and response to therapy of many neoplastic cell types. Here, we show that the promoter of hsp90α gene, that encodes the inducible form of HSP90, is regulated by nuclear factor-κB (NF-κB) activity. Indeed, we found that NF-κB factors bound to one of the two putative consensus sequences present in the hsp90α-flanking region; mutation of such motif hampered the phorbol-myristate-13-acetate-stimulated expression of a luciferase reporter gene under the control of the hsp90α promoter. Furthermore, the downmodulation of NF-κB (p65) levels by a specific small interfering (si) RNA resulted in reducing the levels of endogenous HSP90α protein. These findings disclose a previously unrecognized mechanism that contributes to connect NF-κB factors and HSPs in cell defence machinery.

BAG3 promotes pancreatic ductal adenocarcinoma growth by activating stromal macrophages

The incidence and death rate of pancreatic ductal adenocarcinoma (PDAC) have increased in recent years, therefore the identification of novel targets for treatment is extremely important. Interactions between cancer and stromal cells are critically involved in tumour formation and development of metastasis. Here we report that PDAC cells secrete BAG3, which binds and activates macrophages, inducing their activation and the secretion of PDAC supporting factors. We also identify IFITM-2 as a BAG3 receptor and show that it signals through PI3K and the p38 MAPK pathways. Finally, we show that the use of an anti-BAG3 antibody results in reduced tumour growth and prevents metastasis formation in three different mouse models. In conclusion, we identify a paracrine loop involved in PDAC growth and metastatic spreading, and show that an anti-BAG3 antibody has therapeutic potential.

BAG3 controls angiogenesis through regulation of ERK phosphorylation

BAG3 is a co-chaperone of the heat shock protein (Hsp) 70, is expressed in many cell types upon cell stress, however, its expression is constitutive in many tumours. We and others have previously shown that in neoplastic cells BAG3 exerts an anti-apoptotic function thus favoring tumour progression. As a consequence we have proposed BAG3 as a target of antineoplastic therapies. Here we identify a novel role for BAG3 in regulation of neo-angiogenesis and show that its downregulation results in reduced angiogenesis therefore expanding the role of BAG3 as a therapeutical target. In brief we show that BAG3 is expressed in endothelial cells and is essential for the interaction between ERK and its phosphatase DUSP6, as a consequence its removal results in reduced binding of DUSP6 to ERK and sustained ERK phosphorylation that in turn determines increased levels of p21 and p15 and cell-cycle arrest in the G1 phase.

Characterization of a designed vascular endothelial growth factor receptor antagonist helical peptide with antiangiogenic activity in vivo.

Angiogenesis is a fundamental process underlining physiological and pathological conditions. It is mainly regulated by the vascular endothelial growth factor (VEGF) and its receptors, which are the main targets of molecules able to modulate the angiogenic response. Pharmaceutical therapies based on antiangiogenic drugs represent a promising approach for the treatment of several socially important diseases. We report the biological and structural characterization of a VEGF receptor binder peptide designed on the N-terminal helix of VEGF. The reported experimental evidence shows that the peptide assumes in water a well-defined helical conformation and indicates that this peptide is a VEGF receptor antagonist and possesses antiangiogenic biological activity. In particular, it inhibits VEGF stimulated endothelial cell proliferation, activation, and survival, as well as angiogenesis and tumor progression in vivo. This peptide is a candidate for the development of novel peptide-based drugs for the treatment of diseases associated with excessive VEGF-dependent angiogenesis.

Exposure to 50 Hz electromagnetic field raises the levels of the anti-apoptotic protein BAG3 in melanoma cells†

The expression of the anti‐apoptotic protein BAG3 is induced in several cell types by exposure to high temperature, oxidants, and other stressful agents. We investigated whether exposure to 50 Hz electromagnetic fields raised BAG3 levels in the human melanoma cell line M14, in vitro and in orthotopic xenografts. Exposure of cultured cells or xenografts for 6 h or 4 weeks, respectively, produced a significant (P < 0.01) increase in BAG3 protein amounts. Interestingly, at the same times, we could not detect any significant variation in the levels of HSP70/72 protein or cell apoptosis. These results confirm the stressful effect of exposure to ELF in human cells, by identifying BAG3 protein as a marker of ELF‐induced stress. Furthermore, they suggest that BAG3 induction by ELF may contribute to melanoma cell survival and/or resistance to therapy. J. Cell. Physiol. 226: 2901–2907, 2011.

BAG3 is a novel serum biomarker for pancreatic adenocarcinomas.

to the small number of patients (62.5 vs. 37.5 % , P = 0.11). However, when comparing median cumulative exposure to RBV between groups as measured by the area under the drug exposure curve from week 0 to 12 based on biweekly measurements of RBV plasma levels rather than RBV dosage per se , cumulative exposure to RBV above ≥ 224.3 μ g / dl / day was signifi cantly associated with SVR (odds ratio 8.8; confi dence interval 1.35 – 57.43, P = 0.02) ( Figure 1 ). Anemia in group A was more severe than in group B (mean hemoglobin 99.6 vs. 106.3 g / l; P < 0.001), but well manageable with erythropoietin beta at doses between 9,000 and 30,000 IU per week according to a recently proposed consensus ( 10 ) Except for anemia, adverse events were similar in both groups. In conclusion — and in accordance with the study by Jin et al. ( 7 ) — optimal exposure to RBV guided by therapeutic drug monitoring signifi cantly improves SVR in patients with CHC genotype 1. Th erefore, regular RBV plasma level measurements at least for the fi rst 12 weeks of therapy and RBV dose adjustment may be advocated.

BAG3 regulates formation of the SNARE complex and insulin secretion

Insulin release in response to glucose stimulation requires exocytosis of insulin-containing granules. Glucose stimulation of beta cells leads to focal adhesion kinase (FAK) phosphorylation, which acts on the Rho family proteins (Rho, Rac and Cdc42) that direct F-actin remodeling. This process requires docking and fusion of secretory vesicles to the release sites at the plasma membrane and is a complex mechanism that is mediated by SNAREs. This transiently disrupts the F-actin barrier and allows the redistribution of the insulin-containing granules to more peripheral regions of the β cell, hence facilitating insulin secretion. In this manuscript, we show for the first time that BAG3 plays an important role in this process. We show that BAG3 downregulation results in increased insulin secretion in response to glucose stimulation and in disruption of the F-actin network. Moreover, we show that BAG3 binds to SNAP-25 and syntaxin-1, two components of the t-SNARE complex preventing the interaction between SNAP-25 and syntaxin-1. Upon glucose stimulation BAG3 is phosphorylated by FAK and dissociates from SNAP-25 allowing the formation of the SNARE complex, destabilization of the F-actin network and insulin release.

BAG3 Protein Is Over-Expressed in Endometrioid Endometrial Adenocarcinomas

Endometrioid endometrial cancer is the most common gynaecological tumor in developed countries, and its incidence is increasing. The definition of subtypes, based on clinical and endocrine features or on histopathological characteristics, correlate to some extent with patients prognosis, but there is substantial heterogeneity within tumor types. The search for molecules and mechanisms implied in determining the progression and the response to therapy for this cancer is still ongoing. BAG3 protein, a member of BAG family of co‐chaperones, has a pro‐survival role in several tumor types. BAG3 anti‐apoptotic properties rely on its characteristic to bind several intracellular partners, thereby, modulating crucial events such as apoptosis, differentiation, cell motility, and autophagy. BAG3 expression in human endometrial cancer tissues was not investigated so far. Here, we show that BAG3 protein levels are elevated in tumoral and hyperplastic cells in respect to normal glands. Furthermore, BAG3 subcellular localization appears to be changed in tumoral compared to normal cells. Our results indicate a possible role for BAG3 protein in the maintenance of cell survival in endometrioid endometrial cancer and suggest that this field of studies is worthy of further investigations. J. Cell. Physiol. 232: 309–311, 2017.