Expression of endothelial nitric oxide synthase and vascular endothelial growth factor in oral squamous cell carcinoma: its correlation with angiogenesis and disease progression

PARP inhibitor Veliparib (ABT-888) enhances the anti-angiogenic potentiality of Curcumin through deregulation of NECTIN-4 in oral cancer: Role of nitric oxide (NO)

Concurrent use of DNA damaging agents with PARP inhibitors contribute to the effectiveness of the anticancer therapy. But there is a dearth of reports on the antiangiogenic effects of PARP inhibitors and the suppression of angiogenesis by this drug combination is not yet reported. For the successful development of cancer therapeutics, anti-cancer drugs ought to have anti-angiogenic potentiality along with their DNA damaging abilities. In this current piece of work, we investigated the in vitro and in ovo anti-angiogenic effect of Curcumin and Veliparib (a PARP inhibitor) in oral cancer. Recent evidences suggest an involvement of the NECTIN-4 in cancer angiogenesis and the exact molecular pathway of this involvement remains to be delineated. We observed that the soluble NECTIN-4 secreted from H357 oral cancer cells enhanced the angiogenesis of endothelial cells (HUVECs) and this was inhibited by Curcumin-Veliparib combination. NECTIN-4 enhanced vascularization, induced vasodilation and triggered the angiogenic sprouting via endothelial tip cell filopodia. Data indicated that NECTIN-4 mediated angiogenesis is associated with PI3K-AKT-mediated nitric oxide (NO) formation. A noticeable increase in the NO enhanced epithelial NO level through HIF-1α mediated iNOS activation. We observed that increased NO enhanced the NECTIN-4 mediated eNOS expression and thereby elicited further angiogenesis. Curcumin antagonised the NECTIN-4-induced angiogenesis through inhibition of PI3K-AKT mediated eNOS pathway and Veliparib synergized the effect of Curcumin. Our observations indicate that NO is cardinal in inducing NECTIN-4 mediated angiogenesis in H357 cells. Thus, Curcumin-Veliparib combination suppresses angiogenesis through deregulation of the PI3K-AKT-eNOS pathway downstream to the NECTIN-4.

Endothelial nitric oxide synthase polymorphisms/haplotypes are strong modulators of oral cancer risk in Serbian population

Oral carcinoma is the sixth most common malignancy worldwide, with survival rates of approximately 50%. The major type of oral cancer, present in 90% of the cases, is oral squamous cell carcinoma (OSCC). The genetic background predisposing an individual to OSCC is complex and largely unknown. Studies have suggested that endothelial nitric oxide synthase (eNOS) gene polymorphisms modulate the cancer risk, prompting us to assess the impact of three functional eNOS gene polymorphisms on OSCC risk. The present study included 50 patients with OSCC and 110 controls. Polymerase chain reaction and restriction fragment length polymorphism analysis were used for genotyping of single-nucleotide polymorphisms -786 T/C (rs2070744) and 894 G/T (rs1799983) and variable number of tandem repeats (VNTR) intron 4b/a polymorphism. Homozygous carriers of -786 T/C and intron 4b/a VNTR variant alleles paired with a significant increase of oral cancer risk [odds ratio (OR): 3.63, 95% confidence interval (CI): 1.08-12.21; P = 0.045 and OR: 11.29, 95% CI: 2.71-47.11; P < 0.001, respectively]. When combined, CC and 4b4a genotypes together led to a 21-fold OSCC risk increase (OR: 21, 95% CI: 2.07-213.29; P = 0.006). Haplotype analysis showed that the C-G-4b haplotype conferred an 11-fold increase in OSCC risk. In conclusion, eNOS polymorphisms considerably influence levels of OSCC risk in the Serbian population.

Variances in the Level of COX-2 and iNOS in Different Grades of Endometrial Cancer

BACKGROUND

Many experimental studies have demonstrated the importance of COX-2 in the tumor angiogenesis. Inducible iNOS is responsible for a high and stable level of nitric oxide and is expressed in response to pro-inflammatory factors.

OBJECTIVE

The aim of this study was to evaluate the expression of COX-2 and iNOS at the protein level and to assess their potential prognostic significance in patients with endometrial cancer.

METHODS

The study group consisted of 45 women with endometrial cancer divided according to the degree of histological differentiation i.e. G1, 17; G2, 15; G3, 13. The control group consisted of 15 women without neoplastic changes. The expression of studied proteins was determined immunohistochemically with specific polyclonal antibodies.

RESULTS

Analysis of the COX-2 expression showed that the optical density of the reaction product in G1 reached 186% in the control group, while the values in G2 and G3 reached 243% and 293%, respectively. In the case of iNOS, the optical density of the reaction product reached the following percentages in the control group: 147% in G1, 243% in G2, and 241% in G3.

CONCLUSION

Our findings suggest that changes in the expression of COX-2 and iNOS may be potentially useful in predicting the progression of endometrial cancer and treatment effectiveness.

Spotlight on ROS and β3-Adrenoreceptors Fighting in Cancer Cells

The role of ROS and RNS is a long-standing debate in cancer. Increasing the concentration of ROS reaching the toxic threshold can be an effective strategy for the reduction of tumor cell viability. On the other hand, cancer cells, by maintaining intracellular ROS concentration at an intermediate level called “mild oxidative stress,” promote the activation of signaling that favors tumor progression by increasing cell viability and dangerous tumor phenotype. Many chemotherapeutic treatments induce cell death by rising intracellular ROS concentration. The persistent drug stimulation leads tumor cells to simulate a process called hormesis by which cancer cells exhibit a biphasic response to exposure to drugs used. After a first strong response to a low dose of chemotherapeutic agent, cancer cells start to decrease the response even if high doses of drugs were used. In this framework, β3-adrenoreceptors (β3-ARs) fit with an emerging antioxidant role in cancer. β3-ARs are involved in tumor proliferation, angiogenesis, metastasis, and immune tolerance. Its inhibition, by the selective β3-ARs antagonist (SR59230A), leads cancer cells to increase ROS concentration thus inducing cell death and to decrease NO levels thus inhibiting angiogenesis. In this review, we report an overview on reactive oxygen biology in cancer cells focusing on β3-ARs as new players in the antioxidant pathway.

Regulation of Cell Survival, Apoptosis, and Epithelial-to-Mesenchymal Transition by Nitric Oxide-Dependent Post-Translational Modifications

SIGNIFICANCE

Nitric oxide (NO) is a physiopathological messenger generating different reactive nitrogen species (RNS) according to hypoxic, acidic and redox conditions. Recent Advances: RNS and reactive oxygen species (ROS) promote relevant post-translational modifications, such as nitrosation, nitration, and oxidation, in critical components of cell proliferation and death, epithelial-to-mesenchymal transition, and metastasis.

CRITICAL ISSUES

The pro- or antitumoral properties of NO are dependent on local concentration, redox state, cellular status, duration of exposure, and compartmentalization of NO generation. The increased expression of NO synthase has been associated with cancer progression. However, the experimental strategies leading to high intratumoral NO generation have been shown to exert antitumoral properties. The effect of NO and ROS on cell signaling is critically altered by factors modulating tumor progression such as oxygen content, metabolism, and inflammatory response. The review describes the alteration of key components involved in cell survival and death, metabolism, and metastasis induced by RNS- and ROS-related post-translational modifications.

FUTURE DIRECTIONS

The identification of the molecular targets affected by nitrosation, nitration, and oxidation, as well as their interactions with other post-translational modifications, will improve the understanding on the complex signaling and cell fate decision in cancer. The therapeutic NO-based strategies have to address the complex crosstalk among NO and ROS with regard to critical components affecting tumor cell survival, metabolism, and metastasis in the progression of cancer, as well as close interaction with ionizing radiation and chemotherapy.

Associations of genetic variations of the endothelial nitric oxide synthase gene and environmental carcinogens with oral cancer susceptibility and development

Oral cancer is a major head and neck cancer that is reported to be causally associated with genetic factors and environmental carcinogens. Endothelial nitric oxide synthase (eNOS) was reported to modulate carcinogenesis and progression through nitric oxide (NO) production. Genetic polymorphisms in the eNOS gene can regulate its transcription and further mediate NO production. The purpose of this study was to explore the influences of eNOS gene polymorphisms combined with environmental carcinogens on the predisposition for oral cancer. Two single-nucleotide polymorphisms (SNPs) of the eNOS gene, -786 T > C (rs2070744) and 894G > T (rs1799983), were genotyped in 1200 controls and 1044 patients with oral cancer using a TaqMan-based real-time polymerase chain reaction (PCR). We found that patients who carried the -786 T > C TC genotype were at higher risk for developing an advanced clinical stage (stage III/IV) compared to those with the -786 T > C TT genotype; however, there was no significant association of the two individual SNPs with oral cancer between patients and the control group. According to behavioral exposure to environmental carcinogens, the presence of these two eNOS SNPs combined with tobacco use and/or betel quid chewing profoundly enhanced the risk of oral cancer. Moreover, carriers with the betel quid-chewing habit who had haplotypes of the two eNOS SNPs more easily developed oral cancer. These results indicated an involvement of -786 T > C polymorphisms in the progression of oral cancer and support the interaction between eNOS gene polymorphisms and environmental carcinogens as a predisposing factor of oral carcinogenesis.

Current relevance of hypoxia in head and neck cancer

Head and Neck cancer (HNC) is a complex mix of cancers and one of the more common cancers with a relatively poor prognosis. One of the factors that may assist us in predicting survival and allow us to adjust our treatment strategies is the presence of tumor hypoxia. In this overview we aim to evaluate the current evidence and potential clinical relevance of tumor hypoxia in head and neck cancer according to an extensive search of current literature.An abundance of evidence and often contradictory evidence is found in the literature. Even the contradictory evidence and comparisons are difficult to judge as criteria and methodologies differ greatly, furthermore few prospective observational studies exist for verification of the pre-clinical studies. Despite these discrepancies there is clear evidence of associations between prognosis and poor tumor oxygenation biomarkers such as HIF-1α, GLUT-1 and lactate, though these associations are not exclusive. The use of genetic markers is expanding and will probably lead to significantly more and complex evidence. The lack of oxygenation in head and neck tumors is of paramount importance for the prediction of treatment outcomes and prognosis. Despite the wide array of conflicting evidence, the drive towards non-invasive prediction of tumor hypoxia should continue.

Application of Dynamic Contrast-Enhanced MRI Parameters for Differentiating Squamous Cell Carcinoma and Malignant Lymphoma of the Oropharynx

OBJECTIVE

The purpose of this study was to investigate the usefulness of histogram analysis of dynamic contrast-enhanced MRI (DCE-MRI) parameters for the differentiation of squamous cell carcinoma (SCC) and malignant lymphoma of the oropharynx.

MATERIALS AND METHODS

Pretreatment DCE-MRI was performed in 21 patients with pathologically confirmed oropharyngeal SCC and six patients with malignant lymphoma. DCE-MRI parameter maps including the volume transfer constant (K(trans)), flux rate constant (kep), and extravascular extracellular volume fraction (ve) based on the Tofts model were obtained. Enhancing tumors were manually segmented on each slice of the parameter maps, and the data were collected to obtain a histogram for the entire tumor volume. The Wilcoxon rank sum test was used to compare the histogram parameters of each DCE-MRI-derived variable of oropharyngeal SCC and lymphoma.

RESULTS

Histogram analysis of K(trans) and ve maps revealed that the median and mode of K(trans) were significantly higher in SCC than in lymphoma (p = 0.039 and 0.032, respectively), and the mode, skewness, and kurtosis of ve were significantly different in SCC than in lymphoma (p = 0.046, 0.039, and 0.032, respectively). On ROC analysis, the kurtosis of ve had the best discriminative value for distinguishing between oropharyngeal SCC and lymphoma (AUC, 0.865; cutoff value, 2.60; sensitivity, 83.3%; specificity, 90.5%).

CONCLUSION

Our preliminary evidence using histogram analysis of DCE-MRI parameters based on the whole tumor volume suggests that it might be useful for differentiating SCC from malignant lymphoma of the oropharynx.

The Potential Role of Nitric Oxide in Halting Cancer Progression Through Chemoprevention

Nitric oxide (NO) in general plays a beneficial physiological role as a vasorelaxant and the role of NO is decided by its concentration present in physiological environments. NO either facilitates cancer-promoting characters or act as an anti-cancer agent. The dilemma in this regard still remains unanswered. This review summarizes the recent information on NO and its role in carcinogenesis and tumor progression, as well as dietary chemopreventive agents which have NO-modulating properties with safe cytotoxic profile. Understanding the molecular mechanisms and cross-talk modulating NO effect by these chemopreventive agents can allow us to develop better therapeutic strategies for cancer treatment.

Antioxidant potential, in vitro cytotoxicity and apoptotic effect induced by crude organic extract of Anthracophyllum lateritium against RD sarcoma cells

BACKGROUND

Macrofungi have an established history of use in traditional oriental medicine. Anthracophyllum lateritium is a terrestrial macrofungus found in the dry zone forest reserves in Sri Lanka. Yet there are no scientific reports on bioactive properties of this species. Hence, the current study was aimed at determining the antioxidant potential, in vitro antiproliferative activity and apoptotic effect induced by crude methanolic extract of A. lateritium against RD sarcoma cell line.

METHOD

The crude extract of A. lateritium was dissolved in methanol (MEFCA) and antioxidant activity was evaluated using in vitro assays: inhibition of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging, ferric ion reducing power and 2-deoxy-D-ribose degradation assay. Total phenol and flavonoid contents of MEFCA were assayed using folin Ciocalteu method and aluminium chloride colorimetric method. In vitro cytotoxicity was determined using MTT assay against RD cells after 24 h exposure to MEFCA. Ethidium bromide/ acridine orange staining, DNA fragmentation and protein synthesis experiments were used to study the apoptotic features and antiproliferative activities of the treated cells. Glutathione assay and griess nitrite assay were used to analyze the reduced glutathione content and liberation of nitric oxide from apoptotic cells.

RESULTS

MEFCA showed promising antioxidant activity with EC50 values of 8.00 ± 0.35 μg/mL for DPPH scavenging and 83.33 ± 0.45 μg/mL for 2-deoxy-D-ribose degradation assay. The phenolic content was 265.15 ± 0.46 of (w/w) % of Gallic acid equivalents and flavonoid content was 173.01 ± 0.35 of (w/w) % of Epigallocatechingallate. A. lateritium showed strong in vitro cytotoxic activity with an EC50 of 18.80 ± 4.83 μg/mL for MTT assay against RD cells. Ethidium bromide/acridine orange staining and DNA fragmentation indicated the apoptotic features of treated cells. Protein levels showed a dose dependent decrease supporting the fact that A. lateritium induces apoptosis of treated cells. Glutathione content and nitric oxide content of cells exhibited a dose dependent increase suggesting the apoptosis of RD cells was mediated by both nitrie ions and nitric oxide.

CONCLUSIONS

The crude extract of the A. lateritium exhibited potent antioxidant, antiproliferative activity and apoptotic effect against RD cells providing supportive evidence for the ethnopharmacological use of this fungus in control of oxidative damage and remedy of cancer.

Immunohistochemical expression of vascular endothelial growth factor in canine oral squamous cell carcinomas

Angiogenesis is crucial for the growth and metastasis of malignant tumours, and various proangiogenic factors promote this process. One of these factors is vascular endothelial growth factor (VEGF), which appears to play a key role in tumour angiogenesis. The aim of the present study was to assess whether VEGF expression is associated with angiogenesis, disease progression and neoplastic proliferation in canine oral squamous cell carcinoma (OSCC) tissue. VEGF immunoreactivity was quantified by immunohistochemistry in 30 specimens, including normal oral mucosa and OSCC tissues graded as well, moderately or poorly differentiated. VEGF expression was correlated with tumour cell proliferation, as assessed using the proliferating cell nuclear antigen (PCNA) marker and microvessel density (data already published). The present results revealed that VEGF and PCNA expression increased significantly between normal oral tissue and neoplastic tissue, and between well and moderately/poorly differentiated tumours. In addition, VEGF expression was strongly correlated with PCNA expression and microvessel density. It was concluded that VEGF may promote angiogenesis through a paracrine pathway, stimulating endothelial cell proliferation and, similarly, may induce tumour cell proliferation through an autocrine pathway. The present results suggest that the evaluation of VEGF may be a useful additional criterion for estimating malignancy and growth potential in canine OSCCs.

Production and physiological role of NO in the oral cavity

Nitric oxide (NO) is a free radical which is produced from a wide variety of cells and tissues in the human body. NO is involved in the regulation of many physiological processes, such as vascular relaxation, neurotransmission, immune regulation, and cell death. NO is generated by nitric oxide synthase (NOS), which has three identified isoforms: neuronal type NOS (nNOS), endothelial type NOS (eNOS), and inducible type NOS (iNOS). Different isoforms are expressed depending on the organs, tissues, and cells, and investigation of the types and functions of enzymes expressed in various tissues is underway. The oral cavity is a space in which marked changes have been detected in NO levels, and each tissue is constantly influenced by NO. NO is a component of saliva and is produced by oral bacteria in the oral cavity and released by NOS expressed in oral mucosa. NOS isoforms expressed under normal conditions differ among the oral organs. In addition, the overexpression of NOS was involved in carcinogenesis and tumor growth progression. This review summarized the expression of NOS and functions of NO in oral cavity organs, and their roles in diseases and the influences of treatments.

Different approaches for interpretation and reporting of immunohistochemistry analysis results in the bone tissue - a review

BACKGROUND

Immunohistochemistry (IHC) is a well-established, widely accepted method in both clinical and experimental parts of medical science. It allows receiving valuable information about any process in any tissue, and especially in bone. Each year the amount of data, received by IHC, grows in geometric progression. But the lack of standardization, especially on the post-analytical stage (interpreting and reporting of results), makes the comparison of the results of different studies impossible.

METHODS

Comprehensive PubMED literature search with a combination of search words "immunohistochemistry" and "scoring system" was performed and 773 articles describing IHC results were identified. After further manual analysis 120 articles were selected for detailed evaluation of used approaches.

RESULTS

Six major approaches to the interpretation and presentation of IHC analysis results were identified, analyzed and described.

CONCLUSIONS

The overview of the existing approaches in evaluation and interpretation of IHC data, which are provided in the article, can be used in bone tissue research and for either better understanding of existing scoring systems or developing a new one. Standard multiparametric, semiquantitative IHC scoring systems should simplify and clarify the process of interpretation and reporting of received data.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_221.

Histomorphometric analysis of vascularity in normal buccal mucosa, leukoplakia, and squamous cell carcinoma of buccal mucosa

Context:

Angiogenesis, the process that leads to the formation of new blood vessels, continues to be a topic of major scientific interest. There is an increasing hope that new discoveries will lead to newer therapies that target angiogenesis as a reliable option for disease therapy.

Aims:

The objective of this study was to assess the role of vascularity, correlation of morphometric aspects of vascularity, investigate its usefulness in the histopathological classification and prognosis in normal buccal mucosa (NBM), leukoplakia and squamous cell carcinoma (SCC) of buccal mucosa.

Materials and Methods:

The study sample consisted of 15 cases of NBM, 30 cases of leukoplakia, and 30 cases of SCC of buccal mucosa. The 75 archival samples were stained by hemotoxylin and eosin (H and E) and Masson's trichrome (MT). The stained sections were analyzed using image analysis software.

Statistical analysis used:

Statistical Package for Social Sciences (SPSS) 12.0 statistical software.

Results:

The combined mean vessel density (MVD) of all the cases in H and E was 0.1112 and for MT it was 0.2150. The difference of MVD between H and E and MT was statistically significant. The mean MVD in SCC (0.3455) for MT was higher than NBM (0.1314) and leukoplakia (0.1263). The mean MVD increased from stage III (0.3563) to IV (0.5312). It also increased from NBM (0.1314) to hyperkeratosis (0.1505) and decreased from grade I (0.3556) to II (0.2795) of oral SCC (OSCC).

Conclusions:

MVD can be used as an adjunct with other diagnostic modalities. Further studies are needed to standardize baseline levels for different sites and age groups.

Anti-tumor activity of grape juice concentrate in the rat tongue two-stage initiation-promotion protocol induced by 4-nitroquinoline 1-oxide

The aim of this study was to evaluate the anti-tumor activity of grape juice concentrate following medium-term oral carcinogenesis assay induced by 4-nitroquinoline 1-oxide (4NQO). A total of 30 male Wistar rats were distributed into five groups, as follows (n = 6 per group): Group 1 - negative control group (non-treated group); Group 2 - received grape juice concentrate at 1% dose by gavage for eight consecutive weeks; Group 3 - received 4NQO for 8 weeks at 20 ppm dose in drinking water daily; Group 4 - received 4NQO at 20 ppm dose during 8 weeks in drinking water and treated with grape juice concentrate at 1% dose orally by gavage for first 4 weeks after 4-NQO administration; Group 5 - received 4NQO at 20 ppm dose for 8 weeks in drinking water and treated with grape juice concentrate at 1% dose orally by gavage between the 5th and 8th weeks daily. Histopathological analysis revealed a decrease in hyperplasic and dysplastic lesions in Group 4. Groups 4 and 5 showed decreased COX-2 and TNF-alpha and eNOS gene expression. Grape juice concentrate also increased SOD Cu/Zn and catalase expression. However, Ki-67 immunoexpression was reduced at the promotion step of oral carcinogenesis (G5). Taken together, our results demonstrate that grape juice concentrate modulates rat tongue carcinogenesis as a result of anti-inflammatory activity, antioxidant activity and down-regulation of oral cells proliferation.

Quantitative physiology and immunohistochemistry of oral lesions

Angiogenesis and hypoxia are reported to correlate with tumor aggressiveness. In this study, we investigated the potential of optically measured total hemoglobin concentration (THC) and blood oxygen saturation (StO2) as a quantitative measure of angiogenesis and hypoxia in oral lesions with an immunohistochemical comparison. 12 normal subjects and 40 oral patients (22 oral squamous cell carcinoma (SCC), 18 benign/premalignant lesions including 11 verrucous hyperplasia (VH) and 7 hyperkeratosis/parakeratosis (HK)) were studied. The results showed that the THC measurement was consistent with vascular endothelial growth factor (VEGF) and microvessel staining in the stromal area, but StO2 was not associated with HIF-1α. We observed inflammation induced neovascular formation in the stromal area of VH and HK that were likely attributed to higher-than-control THC and StO2 and resulted in no difference in optical measurements between all lesions. However, we found that in majority of SCC, the ratio of THC and StO2 levels between lesions and the surrounding tissues provide potential distinguishing characteristics from VH, which are not visually differentiable from SCC, with a sensitivity, specificity, and accuracy of 91%, 68%, and 76%, respectively.

Toxicity of ochratoxin a and its modulation by antioxidants: a review

Ochratoxin A (OTA) is a mycotoxin involved in the development of different types of cancers in rats, mice and humans. A growing number of in vitro and in vivo studies has been collected and has described evidence compatible with a role for oxidative stress in OTA toxicity and carcinogenicity. Because the contribution of the oxidative stress response in the development of cancers is well established, a role in OTA carcinogenicity is plausible. Several studies have been performed to try to counteract the adverse effects of oxygen radicals generated under OTA-exposure. A number of molecules with various antioxidant properties were tested, using in vivo or in vitro models. Protection against OTA-induced DNA damage, lipid peroxidation, as well as cytotoxicity were observed, further confirming the link between OTA toxicity and oxidative damage. These studies demonstrated that antioxidants are able to counteract the deleterious effects of chronic consumption or exposure to OTA and confirmed the potential effectiveness of dietary strategies to counteract OTA toxicity.

Nitric oxide and cancer: a review

Nitric oxide (NO), is a ubiquitous, water soluble, free radical gas, which plays key role in various physiological as well as pathological processes. Over past decades, NO has emerged as a molecule of interest in carcinogenesis and tumor growth progression. However, there is considerable controversy and confusion in understanding its role in cancer biology. It is said to have both tumoricidal as well as tumor promoting effects which depend on its timing, location, and concentration. NO has been suggested to modulate different cancer-related events including angiogenesis, apoptosis, cell cycle, invasion, and metastasis. On the other hand, it is also emerging as a potential anti-oncogenic agent. Strategies for manipulating in vivo production and exogenous delivery of this molecule for therapeutic gain are being investigated. However, further validation and experimental/clinical trials are required for development of novel strategies based on NO for cancer treatment and prevention. This review discusses the range of actions of NO in cancer by performing an online MEDLINE search using relevant search terms and a review of the literature. Various mechanisms by which NO acts in different cancers such as breast, cervical, gastric,colorectal, and head and neck cancers are addressed. It also offers an insight into the dichotomous nature of NO and discusses its novel therapeutic applications for cancer prevention and treatment.

Immunohistochemical expression of MMP-9 and VEGF in squamous cell carcinoma of the tongue

Squamous cell carcinomas (SCCs) account for approximately 95% of all oral malignant neoplasms and for about 38% of all malignant head and neck tumors, especially affecting the tongue and lips. The aim of this study was to evaluate the immunohistochemical expression of MMP-9 and VEGF in oral SCC according to the occurrence of metastasis. Eighteen cases of tongue SCC without metastases and 17 cases of tongue SCC with metastases were subjected to immunohistochemical methods. High immunohistochemical expression of MMP-9 and VEGF by neoplastic cells and stroma was observed in tongue SCCs at the invasion front. Metastatic tumors tended to express higher levels of MMP-9 and VEGF than non-metastatic tumors, but the difference was not significant (P > 0.05). Spearman's correlation test showed no significant correlation between VEGF-immunopositive vessels and metastasis (P > 0.05). The present results demonstrate the importance of the expression of MMP-9 and VEGF for the development of SCC of the tongue. However, no significant association was observed between the overexpression of MMP-9 or VEGF and the presence of metastases.

Implications of morphologic patterns of intraepithelial microvasculature observed by narrow-band imaging system in cases of oral squamous cell carcinoma

PURPOSE

To investigate the intraepithelial microvascular morphology of oral squamous cell carcinoma (OSCC) by using narrow-band imaging (NBI) and analyze whether the intraepithelial papillary capillary loop (IPCL) patterns correlate with infiltration depth and disease severity in OSCC.

METHODS

The clinicopathologic data, morphology of vascular architecture as observed by NBI, and histopathology of patients with OSCC were retrospectively reviewed and analyzed.

RESULTS

A total of 80 patients, including 73 males and 7 females with an average age of 54.18±12.23 years, were enrolled. Three patterns of intraepithelial microvasculature were revealed by NBI and differences in these three patterns were significant with regard to pathologic T-classification (p<0.0001), N-classification (p=0.00022), TNM stage (p<0.0001), lymphovascular invasion (p<0.0001), perineural invasion (p=0.000299), depth of tumor infiltration (p<0.0001), and tumor differentiation (p<0.0001). A cut-off point of tumor infiltration of 10.012 mm was best predicted for the destructive pattern of IPCL (sensitivity=100%, specificity=90.0%).

CONCLUSIONS

Three different patterns of IPCL, showing step-wise increased severity according to pathologic parameters, were observed by NBI in cases of OSCC. The pattern indicating IPCL destruction with angiogenesis was associated with more advanced disease stage.

Nitric oxide and oral cancer: a review

Nitric oxide (NO), a short-lived, endogenously produced gas, plays key role in various physiological as well as pathological processes. NO-inducing cell signaling events within the cell producing it and the diffusibility of it in other cells have led to the discovery of various physiological functions of NO including vasodilation, respiration, cell migration, immune response and apoptosis. On the other hand, excessive and unregulated NO synthesis has been implicated in many pathophysiological conditions including cancer. Research on NO, during the past few years is one of the growing areas in cancer biology. The high incidence of oral cancer and precancer has been linked with habits of tobacco chewing and smoking and NO has been said as the "messenger of death" in tobacco related diseases. NO seems to play a part in various stages of carcinogenesis from initiation to progression. However, there is considerable controversy and confusion in understanding its role in cancer biology. It is said to have both, tumoricidal as well as tumor promoting effects and these depend on its timing, location and concentration. Further, NO has also been shown to have antitumor, chemopreventive and therapeutic abilities. Here is an overview in which efforts are made to understand the role of this molecule in oral carcinogenesis.

Dimethylarginine dimethylaminohydrolase/nitric oxide synthase pathway in liver and kidney: protective effect of cyanidin 3-O-β-D-glucoside on ochratoxin-A toxicity

The aim of the present study was to evaluate the effect of long-term cyanidin 3-O-β-D-glucoside (C3G) and/or Ochratoxin A (OTA)-exposure on dimethylarginine dimethylamino hydrolase/nitric oxide synthase (DDAH/NOS) pathway in rats. The experiments were performed in rats supplemented with C3G (1 g/kg feed), OTA (200 ppb), and OTA + C3G. After 4 weeks of daily treatment, liver and kidneys were processed for eNOS, iNOS and DDAH-1 Western blotting, nitrite levels evaluation and DDAH activity determination. Results show that OTA is able to induce iNOS both in kidney and liver, whereas OTA is able to induce eNOS and DDAH-1 overexpression and DDAH activation only in kidney, resulting in increased nitrite levels. In kidney of OTA + C3G fed rats, iNOS, eNOS and DDAH-1 expression were less pronounced compared with those observed in the OTA-treated group. Coherent with the decreased iNOS, eNOS and DDAH-1 expression a decrease in nitrite levels and DDAH activity was observed in the OTA + C3G group. Results demonstrate that C3G is able to counteract the deleterious effects of chronic consumption of OTA and also suggest a possible involvement of iNOS-eNOS-DDAH impairment in OTA nephrocarcinogenity.

Novel inhibitors of nitric oxide synthase with antioxidant properties

We previously described a series of imidazole-based inhibitors substituted at N-1 with an arylethanone chain as interesting inhibitors of neuronal nitric oxide synthase (nNOS), endowed with good selectivity vs endothelial nitric oxide synthase (eNOS). As a follow up of these studies, several analogs characterized by the presence of substituted imidazoles or other mono or bicyclic nitrogen-containing heterocycles instead of simple imidazole were synthesized, and their biological evaluation as in vitro inhibitors of both nNOS and eNOS is described herein. Most of these compounds showed improved nNOS and eNOS inhibitory activity with respect to reference inhibitors. Selected compounds were also tested to analyze their antioxidant properties. Some of them displayed good capacity to scavenge free radicals and ability to reduce lipid peroxidation.

Effects of nitric oxide synthase-3 overexpression on post-translational modifications and cell survival in HepG2 cells

Hepatocarcinoma is the fifth most common neoplasm and the third cause of cancer-related death. The development of genetic- and/or molecular-based therapies is urgently required. The administration of high doses of nitric oxide (NO) promotes cell death in hepatocytes. NO contributes to cell signaling by inducing oxidative/nitrosative-dependent post-translational modifications. The aim of the present study was to investigate protein modifications and its relation with alteration of cell proliferation and death in hepatoma cells. Increased intracellular NO production was achieved by stable nitric oxide synthase-3 (NOS-3) overexpression in HepG2 cells. We assessed the pattern of nitration, nitrosylation and carbonylation of proteins by proteomic analysis. The results showed that NOS-3 cell overexpression increased oxidative stress, which affected proteins mainly involved in cell protein folding. Carbonylation also altered metabolism, as well as immune and antioxidant responses. The interaction of nitrosative and oxidative stress generated tyrosine nitration, which affected the tumor marker Serpin B3, ATP synthesis and cytoskeleton. All these effects were associated with a decrease in chaperone activity, a reduction in cell proliferation and an increased cell death. Our study showed that alteration of nitration, nitrosylation and carbonylation pattern of proteins by NO-dependent oxidative/nitrosative stress was related to a reduction of cell survival in a hepatoma cell line.

Inflammatory infiltrate, microvessel density, vascular endothelial growth factor, nitric oxide synthase, and proliferative activity in soft tissues below intraorally welded titanium bars

BACKGROUND

The aim of the present study is a comparative evaluation of inflammatory infiltrate, microvessel density, vascular endothelial growth factor, nitric oxide synthase, and proliferative activity in soft tissues below intraorally welded titanium bars.

METHODS

Twenty-two patients participated in this study. All patients carried immediately loaded one-stage titanium implants splinted with intraorally welded titanium bars. Each patient underwent two gingival biopsies, a control biopsy harvested from an area of mucosa 5 mm away from the titanium bar and a test biopsy from the mucosa below the titanium bar, which were histologically and immunohistochemically processed.

RESULTS

No fractures or radiographically detectable alterations of the welded frameworks were present. In all the cases examined, the average of the modified plaque index was 1, no suppuration or bleeding on probing was present, and probing depth was < or =3 mm. However, the immunohistochemical analysis revealed some differences. The inflammatory infiltrate was mostly present in test sites and its extension was much larger than in control sites. Statistically significant differences were found in microvessel density and Ki-67 expression among control and test groups (P <0.0001). The high intensity of vascular endothelial growth factor, nitric oxide synthase 1, and nitric oxide synthase 3 expression were mainly detected in the test group, whereas the low intensities were mostly expressed in controls, with statistically significant differences (P <0.0001).

CONCLUSIONS

In the present study, the immunohistochemical analysis shows that the tissues below the titanium bars underwent a higher rate of inflammatory and reparative processes. However, further long-term studies, where clinical and immunohistochemical data are collected in parallel, should be conducted for a better understanding of the expression pattern of inflammation markers.

Immunoexpression of angiogenesis, nitric oxide synthase, and proliferation markers in gingival samples of patients with aggressive and chronic periodontitis

BACKGROUND

In periodontal tissues, angiogenesis seems to be important for the maintenance of healthy tissues and in periodontal diseases. Angiogenesis is regulated through a complex interplay of molecular signals mediated by growth factors involving extracellular matrix remodeling, endothelial cell migration and proliferation, capillary differentiation and anastomosis. However, the influence of angiogenesis in the development, progression, and healing of periodontal lesions is currently under investigation. This immunohistochemical study evaluates the expression of vascular endothelial growth factor (VEGF), microvessel density (MVD), nitric oxide synthase (NOS) 1 and 3, and Ki-67 in gingival tissues of patients with aggressive and chronic periodontitis.

METHODS

Twenty-seven human gingival biopsies were taken from patients with chronic periodontitis (n = 14 patients), generalized aggressive periodontitis (n = 6 patients), and healthy periodontia (n = 7 patients). The specimens were immunohistochemically stained for VEGF, MVD, NOS 1 and 3, and Ki-67.

RESULTS

The levels of VEGF, MVD, NOS 1 and 3, and Ki-67 were found to be significantly different among groups (P >0.001). Patients with aggressive periodontitis had higher levels of these markers compared to those in patients with chronic periodontitis and healthy patients.

CONCLUSIONS

The analysis demonstrates a higher expression of all immunologic markers particularly in subjects with aggressive periodontitis. In summary, the data from this pilot investigation suggests that VEGF is an important factor in the pathogenesis of the aggressive and chronic forms of periodontitis.

Immunohistochemical expression of epidermal growth factor receptor (EGFR) in oral squamous cell carcinoma in relation to proliferation, apoptosis, angiogenesis and lymphangiogenesis

OBJECTIVES

Squamous cell carcinoma (SCC) is by far the most common malignant neoplasm of the oral cavity. A number of etiologic factors have been implicated in its development. During the past few decades, a particular focus has been placed on the investigation of valid biomarkers predictive of cancer behavior and cervical lymph node metastasis in head and neck Squamous cell carcinoma (HNSCC).The present study was designed to investigate the expression of epidermal growth factor in these tumors in relation to proliferation, apoptosis, angiogenesis and lymphangiogenesis.

MATERIALS AND METHODS

Immunohistochemical (IHC) evaluation of epidermal growth factor receptor (EGFR) expression in 40 retrospective OSCC specimens and its correlation with proliferating cell nuclear antigen (PCNA), antiapoptotic antibody (P53), vascular endothelial growth factor (VEGF), and D2-40 monoclonal antibodies (Mab), in relation to the clinicopathological parameters.

RESULTS

Data revealed positive EGFR immunoreactivity in 35(87.5%) cases. There was a statistically significant correlation regarding EGFR extent score with respect to intratumoral lymphatic vessel density (ILVD) (r = 0.35) as well as EGFR intensity score with respect to ILVD and peritumoral lymphatic vessel density (PLVD) (r = 0.33, r = 0.36 respectively). EGFR expression was not correlated with the clinicopathological parameters.

CONCLUSIONS

EGFR is expressed by most of the cases. EGFR correlation with D2- 40 positive lymphatic vessels suggests a higher tendency of OSCC for lymphatic dissemination. Lack of correlation among the studied markers suggests their independent effect on tumor behavior.

Immunohistochemical expression of vascular endothelial growth factor (VEGF) in different types of odontogenic cysts

The objective of the present study was to evaluate vascular endothelial growth factor (VEGF) expression in different types of odontogenic cysts. A total of 25 parakeratotic odontogenic keratocysts (POKCs), 16 orthokeratotic odontogenic keratocysts (OOKCs), and 28 follicular cysts (FCs) were evaluated semiquantitatively for immunohistochemical analysis of VEGF in epithelial cells, endothelial cells of blood vessels, inflammatory cells and focally stromal cells. A significant different expression of VEGF in all cell components was found in keratocysts compared to FCs. The POKCs (80%) and OOKCs (68%) showed more than 50% VEGF positive epithelial cells, whereas the majority of FCs (71%) were either negative in the epithelium or showed less than 10% positive cells. Similarly, the POKCs (88%) and OOKCs (68%) showed more than 50% positive endothelial cells, whereas the FCs (75%) were either negative or showed less than 10% VEGF positive endothelial cells. The highest percentage of cases with score 2 positivity in the stromal cells was observed in POKCs (68%); OOKCs showed a score 2 positivity in 44%, score 1 in 31% and score 0 in 25%, whereas 68% of FCs showed a score 0, 25% a score 1 and only 7% of cases showed a score 2. No statistically significant differences were observed between POKCs and OOKCs in VEGF expression in the epithelial and endothelial cells, whereas the positivity score in stromal cells was significantly higher in POKCs compared to OOKCs. The present results can support the hypothesis that angiogenesis is an active mechanism in the invasive growth of the OKC.

VEGF expression and angiogenesis in oral squamous cell carcinoma: an immunohistochemical and morphometric study

Angiogenesis is involved in tumor progression of oral squamous cell carcinoma (OSCC). In this study, we have investigated by immunohistochemistry vascular endothelial growth factor (VEGF) expression in tumor cells and we have correlated VEGF expression to microvessel area, evaluated by using CD105 as a marker of endothelial cells, in bioptic specimens of 54 human OSCC. Results demonstrated that VEGF is highly expressed in OSCC tumor specimens when compared to pre-neoplastic and normal tissues, without differences between the edge and inside the tumor. Moreover, VEGF expression is reduced in poor differentiated OSCC tumors when compared to moderate and good differentiated forms, and tumor microvessel area is higher in tumors when compared to pre-neoplastic lesions and normal tissues. Finally, VEGF and CD105 may be considered as reliable markers of tumor angiogenesis and progression in OSCC, even if we did not demonstrate any correlation between VEGF expression, tumor microvascular area, clinical stage, and lymph node status.

HIF-1α and VEGF are associated with disease progression in esophageal carcinoma

BACKGROUND

Hypoxia inducible factor-1alpha (HIF-1α) is a transcription factor that regulates the transcription of genes associated with cell proliferation and angiogenesis. The purpose of this study is to clarify the correlation of HIF-1α protein expression with vascular endothelial growth factor (VEGF) and inducible (iNOS), endothelial (eNOS), and neuronal nitric oxide synthase (nNOS) expression in esophageal tumors. Additionally, vascular density in tumor tissue was assessed.

MATERIALS AND METHODS

Eighty-eight esophageal carcinomas were analyzed by immunohistochemistry in paraffin embedded sections.

RESULTS

HIF-1α immunoreactivity was seen in 71.2 % of the tumors. Squamous cell carcinomas expressed more often HIF-1α than adenocarcinomas (P = 0.009). HIF-1α immunoreactivity was associated with iNOS (P = 0.049), and iNOS positivity was also more commonly seen in squamous cell carcinomas than adenocarcinomas (P = 0.016). VEGF immunoreaction tended to associate with HIF-1α (P = 0.073) and iNOS (P = 0.08). ENOS did not associate with HIF-1α, but tended to associate with VEGF (P = 0.072). T1-T2 tumors were more often VEGF negative than T3-T4 tumors (P = 0.063). In the subgroup of 78 operatively treated ECs patients with HIF-1α positivity (> +) had more often distant metastases (P = 0.036). There was no association between iNOS, eNOS, nNOS, or VEGF, and microvessel density in tumor tissue, tumor marginal zone, or in peripheral tissue.

CONCLUSIONS

These results show that there is a link in expression between HIF-1α, iNOS, (eNOS), and VEGF in esophageal cancer. This is in line with the fact of HIF-1α's function as a transcriptional factor for these angiogenic factors. Results also show that squamous cell and adenocarcinomas differ in their expression of HIF-1α and iNOS. VEGF appear to have association with depth of invasion in esophageal carcinomas. In our material HIF-1α positivity was associated with distant metastases, but not with patient survival.

Inhibition of VEGF expression in tongue squamous cancer cells via RNA interference silencing of iNOS gene

The purpose of this study was to investigate the regulatory role of the inducible nitric oxide synthase (iNOS) gene on vascular endothelial growth factor (VEGF) expression in oral squamous cancer cells. The RNA interference (RNAi) technique was used to silence iNOS gene expression by transfecting an expression vector containing short hairpin RNA (shRNA) for iNOS into Tca8113 tongue squamous cancer cells using cationic liposomes. Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting were used to monitor iNOS and VEGF mRNA, as well as protein expression. iNOS mRNA expression was significantly downregulated 24 and 36 h after transfection, and iNOS protein expression was significantly downregulated at 36 and 48 h (P<0.05 versus control), showing that effective silencing was achieved. VEGF mRNA was significantly decreased 24 and 36 h post-transfection, and VEGF protein expression was significantly decreased at 36 and 48 h (P<0.05). RNAi can decrease iNOS gene expression and achieve a gene silencing effect. iNOS gene silencing reduces VEGF expression levels in Tca8113 cells. Thus, there is a relationship between iNOS and VEGF expression in tongue squamous cancer cells.

Clinical significance of vascular endothelial growth factor expression in patients with carcinoma of the mouth floor and tongue

BACKGROUND/AIM

Although there are several types of malignant oral cancers, more than 90% of all diagnosed oral cancers are squamous cell carcinoma (OSCC). Angiogenesis is a cascade-like mechanism which is essential for tumor growth and metastasis. Therefore, vascular endothelial growth factor (VEGF) expression in OSCC and its effect on clinicopathological characteristics and prognosis is of major interest. So far researches have shown that increased expression of this gene, in other words enhanced sinthesis of this protein (VEGF), independently on other factors, increases a chance for local relapse, and distant metastasis. Consequently, patients with OSCC have poor disease-free survival, as well as poor overall survival. The aim of the study was to determine clinical significance of VEGF expression in patients with stage II and III OSCC.

METHODS

This retrospective study analysed 40 patients who had been operated for OSCC of their tongue and the mouth floor. Of these patients, some had stage II and III OSCC with histological grade, G1-G3 and nuclear grade Ng1-Ng3. Two high quality tissue samples were obtained and immunohistochemical expression of VEGF was quantitatively determined by using high microscope amplification. The value of VEGF expression of 20% was rated as significant expression, whereas tumor cells reactivation less than 20% was considered very low or no expression at all. The patients were followed up for a 3-year period.

RESULTS

The obtained results showed that 11 (17.5%) patients had VEGF expression less than 20% and 29 (82.5%) above 20%. A statistical significance was immanent with positive nodal status (p < 0.05) and disease stage (p < 0.05). No statistical correlation was found between the level of VEGF expression and histological and nuclear grade, tumor size, disease relapse or patients overall survival.

CONCLUSION

Inspite the controversy about the prognostic relevance of VEGF our results as well as the results of previous studies, suggest that the expression of VEGF is not reliable as a clinical parameter for the prognosis and disease outcome but it is one of the important factors for the disease progression.

Nitric oxide synthase variants and disease-free survival among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial

PURPOSE

Numerous chemotherapeutic agents are cytotoxic through generation of reactive species, and variability in genes related to oxidative stress may influence disease-free survival (DFS). We examined relationships between DFS and variants in NOS3, as well as NQO1, NQO2, and CBR3, among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial (S8897).

EXPERIMENTAL DESIGN

In the parent trial, women were assigned according to prognostic features; the high-risk group was randomized to cyclophosphamide, i.v. methotrexate, and 5-fluorouracil or to cyclophosphamide, i.v. doxorubicin, and 5-fluorouracil +/- tamoxifen, and the low-risk group did not receive adjuvant therapy. We extracted DNA from normal lymph node tissue and examined functional polymorphisms in NOS3, NQO1, NQO2, and CBR3, in relation to DFS, using Cox proportional hazard model.

RESULTS

There were significant interactions between DFS, adjuvant therapy, and NOS3 Glu298Asp and -786 polymorphisms, alone and in combination (P for interaction = 0.008). When NOS3 genotypes were combined, women with genotypes encoding for lower nitric oxide who received chemotherapy had a >2-fold increase in hazard of progression (hazard ratio, 2.32; 95% confidence interval, 1.26-4.25), whereas there was reduced risk for those who did not receive adjuvant therapy (hazard ratio, 0.42; 95% confidence interval, 0.19-0.95). There were no associations between the other genotypes and DFS in either group.

CONCLUSION

Variants encoding lower activity of NOS3 may affect outcomes in breast cancer patients, with the direction of risk differing depending on chemotherapy status. These results may mirror the known dual functions of nitric oxide and nitric oxide synthase, depending on oxidative environment.

Mast cells and angiogenesis in oral malignant and premalignant lesions

Mast cell contribution to neoangiogenesis during tumorigenesis in oral squamous cell carcinoma is not determined yet. Objectives: To associate numerical mast cell density (MCD) to numerical microvessel density (MVD) during the progression of oral leukoplakia without dysplasia and leukoplakia with dysplasia to squamous cell carcinoma (OSCC). Materials and methods: MVD was analysed immunohistochemically (mouse monoclonal anti-human CD34) in 49 paraffin-embedded specimens, 35 OSCCs, 9 leukoplakias and 5 normal oral tissues. Toluidine blue counterstaining revealed mast cells. MCD and MVD were assessed at the same optical field. Results: MVD increased between: normal oral mucosa, dysplasia (p=0.004), OSCC (p=0.001), leukoplakia and OSCC (p=0.041). MCD increased between: normal oral mucosa, dysplasia (p=0.003), OSCC (p=0.000), leukoplakia and OSCC (p=0.007). MVD was found to depend on MCD (p=0.000) in a percent 28.3% (power curve fit model). Conclusions: Mast cells are attracted at the lesion site and may turn on an angiogenic switch during tumorigenesis in OSCC.

Tumor lymphangiogenesis correlates with lymph node metastasis and clinicopathologic parameters in oral squamous cell carcinoma

BACKGROUND

Lymphatic vessel density (LVD) and microvessel density (MVD) are important parameters for assessing the malignant potential of tumors and patient survival. In this report, the authors defined LVD as the density of D2-40-positive lymphatic vessels and MVD as the density of CD105-positive microvessels per unit area of tissue. It was reported previously that vascular endothelial growth factor C (VEGF-C) is a major modulator of LVD and MVD. The objectives of this study were to clarify the clinical and prognostic significance of both LVD and MVD in oral squamous cell carcinoma (OSCC) and to elucidate the lymphangiogenic and angiogenic activities of VEGF-C in cancer tissues.

METHODS

In total, 110 OSCC tissue samples were evaluated for LVD, MVD, and expression of VEGF-C using immunohistochemistry. Correlations among these parameters and clinicopathologic factors were examined.

RESULTS

LVD was significantly higher in tumors that had very high expression of VEGF-C compared with tumors that had no/weak expression of VEGF-C. LVD correlated well with lymph node metastasis (P < .001). MVD was correlated significantly with positive lymph node metastasis (P < .001) but not with VEGF-C expression. In contrast, high expression of VEGF-C was correlated significantly with advanced tumor status (P = .041). Survival rates were lower in patients who had higher LVD (P < .001), higher MVD (P = .0028), and strong VEGF-C expression (P = .048).

CONCLUSIONS

Lymphangiogenesis predominantly influenced metastasis-free survival. The current results suggested that LVD is a more useful tool than MVD and VEGF-C for deciding on therapeutic strategies in patients with OSCC.

Expression of vascular endothelial growth factor (VEGF) in normal oral mucosa, oral dysplasia and oral squamous cell carcinoma

Vascular endothelial growth factor (VEGF) is a potent angiogenic cytokine implicated in tumour vasculogenesis. A significant increase in vascularity occurs during the transition from normal oral mucosa (NOM), through dysplasia, to squamous cell carcinoma (SCC). This study investigated the presence of VEGF in NOM, oral dysplasia and SCC. The correlation between VEGF expression and the grade of dysplasia or differentiation of SCC was also examined. Specimens consisting of NOM, oral dysplastic lesions and oral SCC were stained using standard immunohistochemistry methods to determine VEGF expression. Statistical analysis indicated an up-regulation of VEGF during the transition from NOM, through dysplasia to SCC. There was also a significant difference in expression according to differentiation of SCC, but not grade of dysplasia. As VEGF is a potent mediator of vascular development, these results suggest that VEGF may play an important role in the maintenance of a blood supply for developing pre-cancerous and invasive oral lesions.

Microvessel density and vascular endothelial growth factor expression in sinus augmentation using Bio-Oss

AIM

The aim of this study was to evaluate microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression in sinus augmentation with Bio-Oss.

METHODS

Twenty patients participated in this study. The sinuses were filled with 100% Bio-Oss. Implants were inserted after 3 months in group A, and 6 months in group B. A trephine was used to harvest bone cores. As control, the pre-existing subantral bone was used.

RESULTS

The mean MVD in control bone was 23.6 +/- 1.8. In the sites augmented with Bio-Oss, at 3 months, the MVD was 23.3 +/- 2.1, while in the sites retrieved at 6 months the MVD was 29.5 +/- 2.4. The difference in MVD between the control bone and group A was not statistically significant. The difference between the control bone and group B was statistically significant (P < 0.05). The statistical analysis showed that the difference in MVD between group A and group B was statistically significant (P < 0.05).

CONCLUSIONS

Bio-Oss seemed to induce an increase in MVD that reached a higher value after 6 months. The percentage of vessels positive to VEGF was higher in group A than in group B. Our data also showed a higher percentage of vessel and stromal cells positive to VEGF and higher MVD values in areas where there was newly formed bone compared with areas where maturation processes were occuring, and this fact could point to a close spatial relationship between angiogenesis and osteogenesis.

Evaluation of expression of midkine in oral squamous cell carcinoma and its correlation with tumour angiogenesis

Midkine, a new member of the heparin-binding growth factor family, was found recently to have a high expression level in many carcinoma specimens, including oesophagus, gall, bladder, pancreas, colorectum, breast and lung carcinomas, but few relevant studies have been performed. The aim of this study was to investigate the expression of midkine in oral squamous cell carcinoma (OSCC) and its correlation with tumour angiogenesis. Surgical specimens from 62 cases of OSCC and 10 cases of normal oral mucosa were examined by immunohistochemistry. The relationship between expression of midkine and the clinicopathological data and tumour angiogenesis was analysed. Midkine proteins were overexpressed in OSCC. The level of midkine expression was found to be significantly correlated with tumour size (P = 0.01), clinical stage (P = 0.002) and prognosis (P = 0.038). High midkine expression was associated with higher tumour angiogenesis as reflected by increased vascular endothelial growth factor expression (P = 0.005) and higher microvessel density (P = 0.004). These results indicate that midkine may be of great value in assessing the development and prognosis of OSCC, and could be taken as a new target for OSCC therapy.

A VEGF165-induced phenotypic switch from increased vessel density to increased vessel diameter and increased endothelial NOS activity

Although vascular endothelial growth factor-165 (VEGF(165)) regulates numerous angiogenic cellular activities, its complex effects on vascular morphology are not highly quantified. By fractal-based, multiparametric branching analysis of 2D vascular pattern in the quail chorioallantoic membrane (CAM), we report that vessel density increased maximally at lower VEGF concentrations, but that vessel diameter and activity of endothelial nitric oxide synthase (eNOS) increased maximally at higher VEGF concentrations. Following exogenous application of human VEGF(165) to the CAM at embryonic day 7, vessel density and diameter were measured after 24 h at arterial end points by the fractal dimension (D(f)) and generational branching parameters for vessel area density (A(v)), vessel length density (L(v)) and vessel diameter (D(v)) using the computer code VESGEN. The VEGF-dependent phenotypic switch from normal vessels displaying increased vessel density to abnormal, dilated vessels typical of tumor vasculature and other pathologies resulted from an approximate threefold increase in VEGF concentration (1.25 to 5 microg/CAM) and correlated positively with increased eNOS activity. Relative to control specimens, eNOS activity increased maximally to 60% following VEGF treatment at 5 microg/CAM, compared to 10% at 1.25 microg/CAM, and was accompanied by no significant change in activity of inducible NOS. In summary, VEGF(165) induced a phenotypic switch from increased vessel density associated with low VEGF concentration, to increased vessel diameter and increased eNOS activity at high VEGF concentration.