Roberto Bei

DNA Vaccination Against Rat Her-2/Neu p185 More Effectively Inhibits Carcinogenesis Than Transplantable Carcinomas in Transgenic BALB/c Mice

The ability of vaccination with plasmids coding for the extracellular and the transmembrane domain of the product of transforming rat Her-2/neu oncogene (r-p185) to protect against r-p185+ transplantable carcinoma (TUBO) cells and mammary carcinogenesis was evaluated. In normal BALB/c mice, DNA vaccination elicits anti-r-p185 Ab, but only a marginal CTL reactivity, and protects against a TUBO cell challenge. Massive reactive infiltration is associated with TUBO cell rejection. In BALB/c mice transgenic for the rat Her-2/neu gene (BALB-neuT), DNA vaccination elicits a lower anti-r-p185 Ab response, no CTL activity and only incompletely protects against TUBO cells, but markedly hampers the progression of carcinogenesis. At 33 wk of age, when control BALB-neuT mice display palpable tumors in all mammary glands, about 60% of immunized mice are tumor free, and tumor multiplicity is markedly reduced. Tumor-free mammary glands still display the atypical hyperplasia of the early stages of carcinogenesis, and a marked down-modulation of r-p185, along with a massive reactive infiltrate. However, BALB-neuT mice protected against mammary carcinogenesis fail to efficiently reject a TUBO cell challenge. This suggests that the mechanisms required for the rejection of transplantable tumors may not coincide with those that inhibit the slow progression of carcinogenesis.

Co-localization of multiple ErbB receptors in stratified epithelium of oral squamous cell carcinoma.

The expression of all four ErbB receptors was compared by immunohistochemistry, using receptor‐specific polyclonal antisera, in 32 invasive, 11 in situ carcinomas, six benign lesions, and 22 samples of histologically normal mucosa adjacent to specimens of carcinoma originating from oral cavity epithelium. Among invasive and in situ carcinoma, EGFR expression was the most prevalent (in 29/32 and 8/11 cases, respectively) followed by ErbB2 (17/32 and 2/11) and ErbB4 (9/32 and 1/10), while ErbB3 was only detected in invasive tumours (12/32). Specific patterns included invasive tumours with expression of EGFR (8/32) or ErbB4 (1/32) alone, as well as different receptor combinations (EGFR+ErbB2, EGFR+ErbB4, EGFR+ErbB2+ErbB3, EGFR+ErbB2+ErbB4, and all four receptors). Simultaneous expression of three or four ErbB receptors correlated with tumour invasion (p=2.2×10−4) and localized in the intermediate epithelial cell layer of well and moderately differentiated tumours. No other significant correlation with clinico‐pathological features was noticed. Some benign lesions and histologically normal mucosa adjacent to carcinomas showed weak immunostaining of EGFR (10/28), ErbB2 (4/28) or ErbB4 (3/28). By comparison, overexpression, as indicated by increased staining intensity, was observed in invasive tumours for EGFR (18/32), ErbB2 (8/32), ErbB4 (3/32), and ErbB3 (3/32). Statistical evaluation demonstrated a significant association of EGFR or ErbB2 overexpression with invasive carcinoma when compared with benign lesions and apparently normal epithelium (p=5.2×10−7 and p=5×10−3, respectively). Tumour‐specific overexpression of ErbB receptors and their co‐expression, most frequently involving EGFR and ErbB2, in the same cell layer of neoplastic epithelium, implicate receptor heterodimers in the pathogenesis of oral squamous carcinoma. Copyright

The effects of dietary flavonoids on the regulation of redox inflammatory networks.

Dietary flavonoids are a large family of polyphenols ubiquitously expressed in plants. Recent evidence show that flavonoids possess several anti-inflammatory activities due to their ability to scavenge reactive oxygen and nitrogen species (ROS and RNS), to inhibit the pro-inflammatory activity of ROS-generating enzymes including cyclooxygenase (COX), lipoxygenase (LOX) and inducible nitric oxide synthase (iNOS) and to modulate different intracellular signaling pathways from NF-kB to mitogen-activated protein kinases (MAPKs) through perturbation of redox-sensible networks in immune cells. This report will review current knowledge on the anti-inflammatory effects of flavonoids on immune cells focusing on their ability to modulate multiple redox-sensible pathways involved in inflammation.

Apigenin induces apoptosis and impairs head and neck carcinomas EGFR/ErbB2 signaling

The development of head and neck squamous cell carcinomas (HNSCCs) is a multistep process progressing from precancerous lesions to highly malignant tumors. A critical role in HNSCCs development and progression is played by EGFR family members including EGFR and ErbB2. The aim of this study was to investigate the effect of apigenin, a low molecular weight flavonoid contained in fruits and vegetables, on growth and survival and on EGFR/ErbB2 signaling in cell lines derived from HNSCCs of the tongue (CAL-27, SCC-15) or pharynx (FaDu). Using sulforhodamine B assay, FACS analysis and activated caspase-3 detection by immunofluorescence, we here demonstrate that apigenin dose-dependently inhibits survival and induces apoptosis of HNSCC cells. Further, by performing western blotting with antibodies specific for phosphorylated EGFR, ErbB2, Erk1/2 and Akt we demonstrate that apigenin reduces ligand-induced phosphorylation of EGFR and ErbB2 and impairs their downstream signaling. On the whole, our results suggest that apigenin properties might be exploited for chemoprevention and/or therapy of head and neck carcinomas.

ErbB2 Immune Response in Breast Cancer Patients with Soluble Receptor Ectodomain

Investigation of ErbB2 immunity in human breast cancer employing recombinant expression sources in immunoblot analysis revealed ErbB2-specific antibodies of the IgG isotype in sera of 14 of 71 cancer patients and 1 of 31 normal donors. Reactivity was confirmed on ErbB2-specific immunoprecipitates. Independent evidence of existing ErbB2 immunity was obtained after in vitro transformation of peripheral blood leukocytes from six positive patients. Furthermore, in vitro immortalization of B-lymphocytes unmasked existent ErbB2 immunity in 1 of 8 patients negative for ErbB2 serum antibodies. Determining shed ErbB2 extracellular domain as an indirect measure of tumor burden in ErbB2-positive malignancy, elevated serum levels were observed in 16 of 71 breast cancer and 1 of 31 normal donor sera. Strikingly, existing ErbB2 immunity correlated significantly with elevated shed ErbB2 ectodomain among the patients analyzed. Incidence of both ErbB2 immunity and elevated ErbB2 extracellular domain increased with a progressed disease stage and was significantly associated with metastatic breast cancer. These observations implicate soluble ErbB2 amounts in vivo in the development of ErbB2 immunity in breast cancer. They further project serum analysis of ErbB2 immunity and soluble ectodomain as potential markers of disease progression in ErbB2-positive malignancy.

Resveratrol and diallyl disulfide enhance curcumin-induced sarcoma cell apoptosis.

Malignant tumors of mesenchimal origin such as rhabdomyosarcoma and osteosarcoma are highly aggressive pedriatic malignancies with a poor prognosis. Indeed, the initial response to chemotherapy is followed by chemoresistance. Diallyl disulfide (DADS), resveratrol (RES) and curcumin (CUR) are dietary chemopreventive phytochemicals which have been reported to have antineoplastic activity on rhabdomyosarcoma and osteosarcoma cells as single drugs. In this study we evaluated whether, as compared to the single compounds, the combination of DADS+RES, DADS+CUR and RES+CUR resulted in an enhancement of their antitumor potential on malignant rhabdoid (SJ-RH4, RD/18) or osteosarcoma (Saos-2) cell lines. Through FACS analysis and activated caspase-3 labeling we demonstrate that CUR induces apoptosis of rabdomyosarcoma and osteosarcoma cells and that this effect is potentiated when CUR is combined with RES or DADS. Further, we explored the effects of the compounds, alone or in combination, on signal transduction pathways involved in apoptosis and growth of cancer cells and show that in rhabdomyosarcoma cells the apoptotic effect of CUR, either alone or in combination, is independent of p53 activity. Our findings suggest that CUR and CUR-based combinations may have relevance for the treatment of p53-deficient cancers, which are often unaffected by conventional chemotherapies or radiotherapy.

Immunohistochemical evidence of immune responses to tumor-associated antigens in lymph nodes of colon carcinoma patients

The authors investigated by immunohistochemical study the drainage of three tumor‐associated antigens in unaffected regional lymph nodes of colon cancer patients. The study was conducted using monoclonal antibodies (MoAb) directed against different epitopes of the tumor‐associated glycoprotein, TAG‐72 (CC‐49, CC‐83, B72.3), of the carcinoembryonic antigen (CEA) (COL‐4, COL‐12), and of the colon‐associated antigen, CAA (anti‐CAA). The authors detected immunohistochemical reactions of MoAb CC‐49 and anti‐CAA with antigen‐presenting cells (APC), such as peritumoral and sinus macrophages and lymphatic endothelial cells and with specific areas of germinal centers in lymph nodes draining 11 of 24 colorectal carcinomas studied. The corresponding primary tumors expressed the TAG‐72 and CAA antigens. No immunostaining was detectable in lymph nodes using the anti‐CEA MoAb, even when the primary tumors strongly expressed the specific epitopes. In germinal centers of regional lymph nodes, the immunostaining was often distributed at the periphery with a characteristic crescentic or circular pattern, which strongly suggested the exposure of the specific epitopes defined by MoAb CC‐49 and anti‐CAA on follicular dendritic cells. This would indicate that these epitopes are selectively recognized and presented to germinal center B‐cells. This phenomenon may have clinical and diagnostic implications.

Inhibition of ErbB receptors, Hedgehog and NF-kappaB signaling by polyphenols in cancer

Carcinogenesis is a multi-step process triggered by cumulative genetic alterations, which drive the progressive transformation of a normal cell into a cancer cell. Among the signal transduction pathways whose cross-talk plays an important role in neoplastic transformation are those mediated by ErbB receptors, NF-kappaB and the Hedgehog (HH)/glioma-associated oncogene (GLI) cascade. Polyphenols can be employed to inhibit the growth of cancer cells due to their ability to modulate the activity of multiple targets involved in carcinogenesis through simultaneous direct interaction or modulation of gene expression. This review will describe the cross-talk between ErbB receptors, NF-kappaB and the Hedgehog (HH)/glioma-associated oncogene (GLI) signaling pathways and the potential role of polyphenols in inhibiting this dialogue and the growth of cancer cells.

Effects of omega-3 polyunsaturated fatty acids on cardiac myocyte protection

Many epidemiologic, observational and randomized human clinical trials have demonstrated beyond doubt the protective cardiovascular effects of omega-3 polyunsaturated fatty acids (PUFAs). Cardiac myocytes protection by omega-3 PUFAs involves several mechanisms which might have a synergistic effect. This review provides a summary of the in vitro and in vivo effects of omega-3 PUFAs on cardiac myocytes health and reports the outcome of a number of clinical trials in patients consuming omega-3 PUFAs.