Mauro Piantelli

FLAVONOIDS APIGENIN AND QUERCETIN INHIBIT MELANOMA GROWTH AND METASTATIC POTENTIAL

Flavonoids are a class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including chemoprevention and tumor growth inhibition. Our aim was to investigate the effects of several polyphenols on the growth and metastatic potential of B16‐BL6 melanoma cells in vivo. Intraperitoneal administration of quercetin, apigenin, (–)‐epigallocathechin‐3‐gallate (EGCG), resveratrol, and the anti‐estrogen tamoxifen, at the time of i.m. injection of B16‐BL6 cells into syngeneic mice, resulted in a significant, dose‐dependent delay of tumor growth, without toxicity. The relative descending order of potency was EGCG > apigenin = quercetin = tamoxifen > resveratrol > control. Furthermore, polyphenols significantly potentiated the inhibitory effect of a non‐toxic dose of cisplatin. When tested for the ability to inhibit lung colonization, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the number of B16‐BL6 colonies in the lungs in a dose‐dependent manner, with quercetin and apigenin being more effective than tamoxifen. Interestingly, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the invasion of B16‐BL6 cells in vitro, with quercetin and apigenin being more effective than tamoxifen. This suggests that anti‐invasive activity is one of the mechanisms underlying inhibition of lung colonization by quercetin and apigenin. In conclusion, quercetin and apigenin inhibit melanoma growth and invasive and metastatic potential; therefore, they may constitute a valuable tool in the combination therapy of metastatic melanoma. Int. J. Cancer 87:595–600, 2000.

90K (Mac-2 BP) and galectins in tumor progression and metastasis.

Galectins and their ligands have been implicated in cell transformation and cancer metastasis, and found to have prognostic value. Mac-2 BP, also known as 90K, is a highly glycosylated, secreted protein extensively studied in human cancer, which binds galectin-1, galectin-3 and galectin-7. High expression levels of 90K are associated with a shorter survival, the occurrence of metastasis or a reduced response to chemotherapy in patients with different types of malignancy. The mechanisms underlying the prognostic significance of 90K and galectins in cancer are far from being understood, although they may be related to the ability of these proteins to interact and, to some extent, modulate cell-cell and cell-matrix adhesion and apoptosis. The resulting scenario is even more complex, as data have been presented that all these proteins might be associated with either a positive or a negative outcome of the patients. It is hypothesised that different galectins and galectin ligands with overlapping or opposite functions, expressed in different tumors during the different steps of the metastatic cascade might play a crucial role in tumor progression. Published in 2004.

Dietary zinc supplementation of 3xTg-AD mice increases BDNF levels and prevents cognitive deficits as well as mitochondrial dysfunction

The overall effect of brain zinc (Zn2+) in the progression and development of Alzheimers disease (AD) is still not completely understood. Although an excess of Zn2+ can exacerbate the pathological features of AD, a deficit of Zn2+ intake has also been shown to increase the volume of amyloid plaques in AD transgenic mice. In this study, we investigated the effect of dietary Zn2+ supplementation (30 p.p.m.) in a transgenic mouse model of AD, the 3xTg-AD, that expresses both β amyloid (Aβ)- and tau-dependent pathology. We found that Zn2+ supplementation greatly delays hippocampal-dependent memory deficits and strongly reduces both Aβ and tau pathology in the hippocampus. We also evaluated signs of mitochondrial dysfunction and found that Zn2+ supplementation prevents the age-dependent respiratory deficits we observed in untreated 3xTg-AD mice. Finally, we found that Zn2+ supplementation greatly increases the levels of brain-derived neurotrophic factor (BDNF) of treated 3xTg-AD mice. In summary, our data support the idea that controlling the brain Zn2+ homeostasis may be beneficial in the treatment of AD.

Quercetin inhibits p21‐RAS expression in human colon cancer cell lines and in primary colorectal tumors

Immunocytochemical studies have revealed that 10 μM quercetin reduced the steady state levels of p21‐ras proteins in both colon cancer cell lines and primary colorectal tumors. These findings were confirmed by Western blot and flow cytometric analysis showing that the inhibition of p21‐ras expression by quercetin was time‐ and concentration‐dependent. Twenty‐four‐hour treatment with 10 μM quercetin reduced p21‐ras levels to about 50% of control values. Quercetin was similarly effective in inhibiting the expression of K‐, H‐, and N‐ras proteins. Moreover, the effect of quercetin on ras oncogene expression was not dependent on the cell cycle position of colon cancer cells and appeared to be specific and not merely a consequence of overall inhibition of protein synthesis. Northern blot analysis revealed that quercetin produced in colon cancer cells an early (30 min) reduction of the steady state levels of K‐, H‐, and N‐ras mRNAs. This reduction was also present after 6 hr of flavonoid treatment. These effects of quercetin suggest a possible chemopreventive role for this compound in colorectal carcinogenesis. Int. J. Cancer 85:438–445, 2000. ©2000 Wiley‐Liss, Inc.

Effects of dietary supplementation of carnosine on mitochondrial dysfunction, amyloid pathology, and cognitive deficits in 3xTg-AD mice.

Background The pathogenic road map leading to Alzheimers disease (AD) is still not completely understood; however, a large body of studies in the last few years supports the idea that beside the classic hallmarks of the disease, namely the accumulation of amyloid-β (Aβ) and neurofibrillary tangles, other factors significantly contribute to the initiation and the progression of the disease. Among them, mitochondria failure, an unbalanced neuronal redox state, and the dyshomeostasis of endogenous metals like copper, iron, and zinc have all been reported to play an important role in exacerbating AD pathology. Given these factors, the endogenous peptide carnosine may be potentially beneficial in the treatment of AD because of its free-radical scavenger and metal chelating properties. Methodology In this study, we explored the effect of L-carnosine supplementation in the 3xTg-AD mouse, an animal model of AD that shows both Aβ- and tau-dependent pathology. Principal Findings We found that carnosine supplementation in 3xTg-AD mice promotes a strong reduction in the hippocampal intraneuronal accumulation of Aβ and completely rescues AD and aging-related mitochondrial dysfunctions. No effects were found on tau pathology and we only observed a trend toward the amelioration of cognitive deficits. Conclusions and Significance Our data indicate that carnosine can be part of a combined therapeutic approach for the treatment of AD.

Axillary Lymph Node Nanometastases Are Prognostic Factors for Disease-Free Survival and Metastatic Relapse in Breast Cancer Patients

Purpose: Early breast cancer presents with a remarkable heterogeneity of outcomes. Undetected, microscopic lymph node tumor deposits may account for a significant fraction of this prognostic diversity. Thus, we systematically evaluated the presence of lymph node tumor cell deposits ≤0.2 mm in diameter [pN0(i+), nanometastases] and analyzed their prognostic effect. Experimental Design: Single-institution, consecutive patients with 8 years of median follow-up (n = 702) were studied. To maximize chances of detecting micrometastases and nanometastases, whole-axilla dissections were analyzed. pN0 cases (n = 377) were systematically reevaluated by lymph node (n = 6676) step-sectioning and anticytokeratin immunohistochemical analysis. The risk of first adverse events and of distant relapse of bona fide pN0 patients was compared with that of pN0(i+), pN1mi, and pN1 cases. Results: Minimal lymph node deposits were revealed in 13% of pN0 patients. The hazard ratio for all adverse events of pN0(i+) versus pN0(i−) was 2.51 (P = 0.00019). Hazards of pN1mi and pN0(i+) cases were not significantly different. A multivariate Cox model showed a hazard ratio of 2.16 for grouped pN0(i+)/pN1mi versus pN0(i−) (P = 0.0005). Crude cumulative incidence curves for metastatic relapse were also significantly different (Grays test χ2 = 5.54, P = 0.019). Conclusion: Nanometastases are a strong risk factor for disease-free survival and for metastatic relapse. These findings support the inclusion of procedures for nanometastasis detection in tumor-node-metastasis staging.

A Bicistronic CYCLIN D1-TROP2 mRNA Chimera Demonstrates a Novel Oncogenic Mechanism in Human Cancer

A chimeric CYCLIN D1-TROP2 mRNA was isolated from human ovarian and mammary cancer cells. The CYCLIN D1-TROP2 mRNA was shown to be a potent oncogene as it transforms naïve, primary cells in vitro and induces aggressive tumor growth in vivo in cooperation with activated RAS. Silencing of the chimeric mRNA inhibits the growth of breast cancer cells. The CYCLIN D1-TROP2 mRNA was expressed by a large fraction of the human gastrointestinal, ovarian, and endometrial tumors analyzed. It is most frequently detected in intestinal cell aneuploid cancers and it is coexpressed with activated RAS oncogenes, consistent with a cooperative transforming activity in human cancers. The chimeric mRNA is a bicistronic transcript of post transcriptional origin that independently translates the Cyclin D1 and Trop-2 proteins. This is a novel mechanism of CYCLIN D1 activation that achieves the truncation of the CYCLIN D1 mRNA in the absence of chromosomal rearrangements. This leads to a higher CYCLIN D1 mRNA stability, with inappropriate expression during the cell cycle. The stabilized CYCLIN D1 mRNA cooperates with TROP2 in stimulating the growth of the expressing cells. These findings show a novel epigenetic, oncogenic mechanism, which seems to be widespread in human cancers.

nm23 in ovarian cancer: correlation with clinical outcome and other clinicopathologic and biochemical prognostic parameters

PURPOSE The aim of the study was to define the prognostic role of the metastasis suppressor gene, nm23, in 106 primary ovarian cancer patients. PATIENTS AND METHODS Northern and Western blotting analysis of nm23-H1 and nm23-H2 expression were performed in a subset of ovarian tumors. Immunohistochemical analysis was performed on formalin-fixed paraffin-embedded specimens from 106 primary ovarian carcinomas by the antihuman nm23 monoclonal antibody. RESULTS Northern and Western blotting analysis demonstrated a direct association between nm23-H1 and nm23-H2 levels. Moreover, an overall concordance of 86.7% between Northern blotting and immunohistochemical data was observed. Sixty-six specimens (68%) showed a positive nm23-H1 immunoreaction. The percentage of nm23-H1 positivity was higher in lymph node-negative (70%) than in lymph node-positive cases (44%) (P = .049). Moreover, the percentage of complete/partial responses to chemotherapy was higher in nm23-H1-positive (69%) than in nm23-H1-negative (44%) patients (P = .03). The percentage of epidermal growth factor receptor (EGFR) positive cases was lower in nm23-H1-positive (44%) than in nm23-H1-negative immunostained (72%) samples (P = .012). Lower ras/p21 levels (median, 1.77 absorbance units) were found in nm23-H1-positive than in nm23-H1-negative samples (median, 2.63 absorbance units) (P = .03). The 6-year progression-free survival (PFS) rate of nm23-H1-positive cases was 50% (95% confidence interval [CI], 33 to 67) versus 12% (95% CI, -2 to 26) for nm23-H1-negative patients (P = .0056). In multivariate analysis, only stage, ascites, and nm23-H1 content retained independent prognostic roles. CONCLUSION The assessment of nm23 content may provide useful information for prognostic characterization of ovarian cancer patients.

Flavonoids inhibit melanoma lung metastasis by impairing tumor cells endothelium interactions

Flavonoids comprise a class of low molecular weight compounds displaying a variety of biological activities including inhibition of tumor growth and metastasis. To gain insight into the mechanisms underlying metastasis inhibition, we have employed the B16‐BL6 murine melanoma metastasis model. B57BL/6N mice were injected i.v. with tumor cells and Apigenin, Quercetin, or Tamoxifen, each at 50 mg/kg given i.p., and lung tumor cell colonies counted 14–6 days thereafter. Three different injection schedules were used for each drug: (a) daily injection, starting 24 h before injection of the tumor cells; (b) single dose, 24 h preceding tumor challenge; (c) daily injection, starting 24 h after the injection of the tumor cells. All three compounds significantly reduced tumor lung deposits (Apigenin = Quercetin > Tamoxifen). However, when treatment was delayed by 24 h after tumor cells (schedule c), multiple daily doses of Apigenin or Quercetin were less effective that a single dose of the same compound given 24 h before tumor challenge (schedule b). Apigenin and Quercetin, but not Tamoxifen, were found to inhibit VCAM‐1 expression in a dose‐dependent manner in HUVEC and in murine pulmonary endothelial cells. In ex vivo experiments, the number of tumor cells adhering to lung vessels was significantly diminished in animals treated with a single dose of Apigenin and Quercetin. These findings indicate that the inhibition of tumor cell metastasis by Apigenin or Quercetin may significantly depend on the ability of these compounds to alter the hosts microenvironment, further substantiating the role of the intravascular processes in the metastatic cascade. J. Cell. Physiol. 207: 23–29, 2006.

GROWTH-INHIBITORY EFFECT OF TAMOXIFEN AND QUERCETIN AND PRESENCE OF TYPE II ESTROGEN BINDING SITES IN HUMAN LARYNGEAL CANCER CELL LINES AND PRIMARY LARYNGEAL TUMORS

Quercetin and tamoxifen, in a range of concentrations between 0.01 and 5 μM, exert a dose‐dependent inhibition on the anchorage‐dependent and anchorage‐independent cell growth of Hep2 and CO‐K3 laryngeal cancer cell lines. Cell cycle analysis revealed that the growth‐inhibitory effect was associated with a block of the cells at the G2/M checkpoint of the cell cycle followed by DNA fragmentation. This suggests that the failure of cells to proceed through the G2/M checkpoint can be a trigger for apoptosis. The induction of apoptosis by quercetin and tamoxifen was confirmed immunocytochemically by the in situ nick end labeling (TUNEL) reaction. These compounds also exerted a dose‐dependent growth‐inhibitory effect on primary tumor cells, as assessed by colony‐forming assay and bromodeoxyuridine labeling. Laryngeal cancer cell lines and primary tumor cells expressed Type II estrogen binding sites (Type II EBS) with binding characteristics similar to those of Type II EBS in other tumor cells. Since the affinities of quercetin and tamoxifen for Type II EBS were correlated with their growth‐inhibitory potential while ipriflavone neither interacted with these sites nor inhibited cell growth, the possibility exists that the action of these compounds is mediated, at least in part, by the interaction with Type II EBS. In conclusion, our data indicate that quercetin and tamoxifen could be potentially useful in laryngeal cancer treatment. Int. J. Cancer 77:747–754, 1998.