Oral Oncology - Articles in Press

Socio-economic status and head and neck cancer incidence in Canada: A case-control study - Corrected Proof

Stephanie Johnson, James Ted McDonald, Martin Corsten, Ryan Rourke — 2010-02-08

Summary: In an earlier study we identified an increased incidence of head and neck cancer (HNC) in individuals with lower socio-economic status (SES) in the United States. The objective of this study was to determine if lower SES is associated with a similar increase in the incidence of HNC in Canadian patients.We obtained data on SES (income, education and immigration status), demographic characteristics, frequency of dental visits and smoking behavior for adult patients residing in the Eastern Ontario region who were referred to the Ottawa Regional Cancer Centre with HNC. We compared the SES and frequency of dental visits of these HNC patients with the SES and frequency of dental visits of a control sample in the same region from the 2004–2005 Statistics Canada Canadian Community Health Survey (CCHS 3.1). We then performed a logistic regression analysis on the combined sample of patients and controls using incidence of HNC as the dependent variable. This allowed us to eliminate confounding variables such as tobacco intake and to isolate the effect of SES, frequency of dental visits, and immigration status on HNC incidence.There was a statistically significant decrease in the incidence of HNC among adults with a higher median family income (OR=0.5429, CI=[.3352, .8795]). Also, adults with less than grade 8 education had significantly higher rates of HNC than adults who had completed high school (OR 3.65, CI=[1.88, 7.08]). As well, immigrants had a significantly lower incidence of HNC than Canadian born adults (OR=0.3825, CI=[.2063, .7090]). Lastly, we found that individuals who typically visited a dentist less than once per year had a significantly higher incidence of HNC than individuals who typically visited a dentist at least once per year (OR=1.69, CI=[1.01, 2.83]).Even when controlling for tobacco intake, the incidence of HNC in Eastern Ontario was higher in patients with lower median family income and less than grade 8 education. It was higher in individuals who visited a dentist less than once per year, and lower in immigrants to Canada. This was similar to what has been observed in the United States. Further study into the reason for this increased incidence of HNC in patients with lower SES is warranted.

miR-24 up-regulation in oral carcinoma: Positive association from clinical and in vitro analysis - Corrected Proof

2010-02-08

Summary: MicroRNAs (miRNAs) play important roles in neoplastic process. miR-24 is localized on chromosome 9q22 and 19p13, regions frequently altered in oral squamous cell carcinoma (OSCC). This study showed that miR-24 was up-regulated in OSCC tissues relative to control samples. In addition, the plasma levels of miR-24 in OSCC patients were significantly higher than in control individuals. miR-24 expression was also higher in OSCC cell lines relative to normal oral keratinocytes. Experiments blocking miR-24 and using exogenous miR-24 expression indicated that miR-24 contributes to the growth of OSCC cells and that miR-24 may target p57. This study suggests that miR-24 is involved in the regulation of OSCC growth and that the miR-24’s level in plasma may be validatable as a tumor marker for OSCC patients.

Kaposi’s sarcoma of the head and neck: A review - Corrected Proof

Velia Ramírez-Amador, Gabriela Anaya-Saavedra, Guillermo Martínez-Mata — 2010-02-08

Summary: Important advances in Kaposi’s sarcoma (KS) knowledge have been achieved, but KS is still a dilemma. It is an angioproliferative disorder classified as an intermediate neoplasm due to the absence of conventional clinical features of malignancy, but at the moment, it remains unclear if KS could be considered a reactive proliferation of endothelial cells and spindle cells, a true malignancy or both. In this review, the authors address the main epidemiological, clinical, and biological features, of the five types of KS, with emphasis on KS affecting the head and neck region. Also, a revision is done in relation with transmission, the role of saliva, and the pathogenic events associated with human herpesvirus type-8 (HHV-8). Treatment options are revised, highlighting the need for future approaches focused on targeting signaling pathways.

Characterization of different tissue changes in normal, betel chewers, potentially malignant lesions, conditions and oral squamous cell carcinoma using reflectance confocal microscopy: Correlation with routine histopathology - Corrected Proof

2010-02-08

Summary: The goal of this study was to characterize the features of normal mucosa, mucosa in betel chewers and smokers, potentially malignant lesions and squamous cell carcinoma of oral mucosa using reflectance confocal microscopy.Oral cavity biopsies were acquired from 25 patients from College of Dental Surgery, Saveetha University who underwent screening for suspected lesions of Oral precancer and Oral cancer along with normal patients who underwent impaction. Biopsies were acquired from the clinically suspicious area and immediately placed in Dulbecco modified eagles growth medium (DMEM). Reflectance confocal images were obtained at multiple image plane depths from biopsies within 6h of excision. After imaging, biopsies were fixed in 10% formalin and submitted for routine histopathological examination by an experienced oral and maxillofacial pathologist. Reflectance confocal images were compared with histological images from the same sample to determine the tissue features which contribute to early cellular changes, image contrast and early diagnosis.The confocal images were obtained to a depth of up to 150microns on intact biopsy specimens and subsequent 3-dimensional images, keratin thickness measurements, cell measurements, cell density analysis and graphical representations were performed using Leica image analysis software. In normal mucosa keratin deposition were seen as alternating dark and bright stacks and in different cell layers the nuclei were seen as disks of varying intensities. In pre-cancerous lesions the keratin thickness and cell nuclear density were found to be increased when compared to normal controls. In OSMF cases confocal images of fibrosis show scattering from individual fibres as hyperdense areas. Oral squamous cell carcinoma cases demonstrated extensive variations in cell size, nuclear size and nuclear morphology. At cellular level, dysplastic features like increased nuclear density, increased nuclear cytoplasmic ratio, nuclear and cellular pleomorphism with loss of cohesiveness were identified in all five cases.Our results support the potential of reflectance confocal microscopy to play a significant role in clinical evaluations of oral lesions, early diagnosis of potentially malignant and malignant oral lesions and real time identification of tumour margins.

Plasmablastic lymphoma of the oral cavity: A review - Corrected Proof

Sachin C. Sarode, Gargi S. Sarode, Anuprita Patil — 2010-02-08

Summary: Plasmablastic lymphoma (PBL) is a rare AIDS associated non-Hodgkin’s lymphoma (NHL), with predilection for the mucosa of oral cavity. It usually has a plasmablastic morphology, expressing plasma cell-associated antigens with weak or no expression of B-cell associated markers. The tumor cells also show monoclonal rearrangement of the immunoglobulin heavy chain gene (IgH) and/or clonal restriction of Ig light chain (IgL) gene expression in most of the cases. An etiological role for EBV seems likely but the association with HHV8 is questionable. The treatment guidelines for PBL are not well defined and patients have been treated heterogeneously with chemo and/or radiotherapy, although the prognosis is poor. The present article discusses the 68 cases reported in English medical literature with comprehensive review on PBL involving the oral cavity.

Scintigraphic evaluation of mandibular bone turnover in patients with solid tumors receiving zoledronic acid - Corrected Proof

Tim Van den Wyngaert, Manon T. Huizing, Eric Fossion, Jan B. Vermorken — 2010-02-08

Summary: Bisphosphonates (BP) have been associated with the occurrence of osteonecrosis of the jaw (ONJ), possibly by causing an excessive bone turnover inhibition. However, little in vivo evidence exists to support this theory.The 99mTc-medronate scintigrams of patients with skeletal metastases and BP use (n=40) were individually matched with cancer patients without BP exposure (n=40) and controls with neither malignancy nor BP use (n=40). Patients with established ONJ or intense focal abnormalities in the studied regions were excluded. Mandibular (MBT) bone turnover was quantified relative to the femur by defining regions-of-interest with correction for background activity.The patients with BP exposure (34 female, 6 male) had a median age of 63years (range 25–81) and received a median number of 11 zoledronic acid administrations (range 1–44). Most patients suffered from breast cancer (n=30). The mean ratio of the MBT in cancer patients with BP use over non-users was 0.88 (95% CI 0.80–0.96; p=0.003), and 0.83 (95% CI 0.73–0.94; p=0.001) when BP using oncological patients were compared with controls without malignancy or BP use. The ratio of MBT’s between BP naive patients was 0.95 (95% CI 0.83–1.07; p=0.8). No dose–response effect between the number of BP administrations and MBT could be demonstrated (r=0.02; p=0.9).These findings suggest that, relative to the femur, BP exert a stronger effect on mandibular bone turnover, which strengthens the hypothesis that the inhibition of bone turnover may be important in the pathophysiology of ONJ.

Impact of second primary esophageal or lung cancer on survival of patients with head and neck cancer - Corrected Proof

2010-02-08

Summary: Second cancers following head and neck cancer (HNC) most often involve the esophagus and lung, yet the actual magnitude of impact of second primary esophageal or lung cancer on survival of HNC patients has not been well established, particularly by a large-scale epidemiological study. To provide a quantitative estimate of the survival impact, we conducted a population-based study including 63,720 cases of HNC subsets, of which 3658 developed at least one second primary malignancy, 253 had a second esophageal cancer and 388 had a second lung cancer. A Cox proportional hazards model which included age at initial cancer diagnosis and gender were employed to compare the survival rates between patients with different types of second cancers. Our results showed that the second esophageal or lung cancer contributed to a poorer outcome than the other types of second cancer, regardless of the index tumor site (all Ps⩽0.019). The overall median survival was 0.76±0.04 and 0.72±0.08years for second esophageal and lung cancers, respectively. Compared to those without second cancers, the patients with second esophageal or lung cancer were associated with a significant reduction in survival, with an estimated 31–105% excess risk of death according to the site of the primary index tumor. In conclusion, the second esophageal and lung cancers have a significantly negative impact on the survival of HNC patients, thereby calling for a more effective program for surveillance and chemoprevention for these two sites.

Arecoline arrests cells at prometaphase by deregulating mitotic spindle assembly and spindle assembly checkpoint: Implication for carcinogenesis - Corrected Proof

2010-02-08

Summary: One apparent feature of cancerous cells is genomic instability, which may include various types of chromosomal aberrations, such as translocation, aneuploidy, and the presence of micronuclei inside the cells. Mutagenic factors that promote the emergence of genomic instability are recognized as risk factors for the development of human malignancies. In Asia, betel quid (BQ) chewing is one of such risk factors for oral cancer. Areca nut is an essential constitute of BQ and is declared as a group I carcinogen by the International Agency for Research on Cancer. However, the molecular and cellular mechanisms regarding the carcinogenicity of areca nut are not fully explored. Here we reported that arecoline, a major alkaloid of areca nut, could arrest cells at prometaphase with large amounts of misaligned chromosomes. This prometaphase arrest was evidenced by condensed chromosome pattern, increased histone H3 phosphorylation, and accumulation of mitotic proteins, including aurora A and cyclin B1. To investigate the molecular mechanisms accounting for arecoline-induced prometaphase arrest, we found that arecoline could stabilize mitotic spindle assembly, which led to distorted organization of mitotic spindles, misalignment of chromosomes, and up-regulation of spindle assembly checkpoint (SAC) genes. The SAC proteins BubR1 and Mps1 were differentially modified between the cells treated with arecoline and nocodazole. This together with aurora A overexpression suggested that SAC might be partly suppressed by arecoline. As a result, the arecoline-exposed cells might produce progeny that contained various chromosomal aberrations and exhibited genomic instability.

Nuclear Survivin expression is correlated with malignant behaviors of head and neck cancer together with Aurora-B - Corrected Proof

2010-02-08

Summary: Survivin belongs to the inhibitors of apoptosis (IAP) gene family and inhibits apoptosis. Besides its role as IAP, Survivin recently appears to function as a subunit of the chromosomal passenger complex (CPC) for regulating cell division with other CPC proteins including Aurora-B and INCENP. Nuclear Survivin is suspected to control cell division, whereas cytoplasmic Survivin is considered cytoprotective. Although there are several studies on Survivin expression and its function as inhibition of apoptosis, there is no study on Survivin function as a CPC and its correlation with other CPC proteins in head and neck squamous cell carcinoma (HNSCC). Here, therefore, we examined nuclear Survivin expression and its functional correlation with Aurora-B in HNSCC. High expression of Survivin was well correlated with Aurora-B expression in nuclear fraction of HNSCC cell lines and tissues. Moreover, nuclear Survivin expression was significantly correlated with Ki-67 and Aurora-B expression by immunohistochemistry. Notably, HNSCC cases with nuclear Survivin and Aurora-B expression exhibited marked malignant behaviors. Interestingly, both Survivin and Aurora-B knockdown inhibited cell growth and tumorsphere formation. Overall suggest that nuclear Survivin may be involved in tumor progression together with Aurora-B, and that Survivin and Aurora-B can be useful diagnostic markers and therapeutic targets.

Multivariate analyses to assess the effect of surgeon volume on survival rate in oral cancer: A nationwide population-based study in Taiwan - Corrected Proof

Ching-Chih Lee, Hsu-Chueh Ho, Pesus Chou — 2010-02-08

Summary: Patients with oral cancer utilize considerable health care resources, particularly when wide resection of the tumor and reconstruction with pedicle flap/free flap is performed. This study was conducted to explore the relationship between survival rates and surgeon volume. A total of 1256 patients who underwent resections for oral cancer in 2005 were identified from the Taiwan National Health Insurance Research Database. Survival analysis, the Cox proportional regression model, and propensity score were used to evaluate the association between 3-year survival rates and surgeon caseloads. Oral cancer patients treated by high-volume surgeons (caseload 22–117) had better survival rates (hazard ratio [HR]=0.656; 95% confidence interval [CI], 0.484–0.89; P=0.007) using the Cox proportional regression model after adjusting for patients’ comorbid conditions, hospital, and surgeon characteristics. When analyzed by propensity score, the adjusted 3-year survival rate was 74% for patients treated by high-volume surgeons compared to 58% in the low/medium-volume group (P=0.019). We concluded that for patients who underwent oral cancer resection and reconstruction, after adjusting for differences in the case mix, high-volume surgeons had better 3-year survival rates. Treatment strategies adopted by high-volume surgeons should be analyzed further and utilized more widely.

Potential biomarkers in saliva for oral squamous cell carcinoma - Corrected Proof

2010-02-08

Summary: Sensitive and reliable early diagnostic markers for oral squamous cell carcinoma (OSCC) remain unavailable. Early identification of recurrence for OSCC is also a challenge. Unlike the other deep cancers, OSCC is located in oral cavity. The DNA, RNA, and protein derived from the living cancer cells and inflammatory cells then can be conveniently obtained from saliva. High-throughput genomic and proteomic approaches have been carried out to identify the potential biomarkers in body fluids such as saliva and blood for diagnosis and prognosis of OSCC. This article reviewed the recently identified biomarkers from saliva for OSCC. In addition, the biomarkers which have been correlated with OSCC tumor malignancy by molecular pathology analysis are also described. Finally, the potential biomarkers that have been demonstrated to associate with the malignant OSCC may be used for salivary screening for high-risk patients are suggested. This article may help to identify the potential biomarkers for screening and the molecular pathology analysis for high-risk patients of OSCC. Effective screening to identify high-risk patients can allow the clinician to provide the appropriate treatment without delay and to reduce the recurrence of OSCC.

Surgical outcomes and prognostic factors of oral cancer associated with betel quid chewing and tobacco smoking in Taiwan - Corrected Proof

2010-02-08

Summary: Oral squamous cell carcinoma (OSCC) is one of the most common cancers in geographic regions where betel quid (BQ) chewing is prevalent; OSCC is an extremely malignant neoplasm whose prognostic factors are multiple and complex. The purpose of this study was to assess clinicopathological prognostic factors and treatment outcomes in 698 consecutive OSCC patients who had undergone surgery as the primary treatment in an area with a high prevalence of both betel quid chewing and tobacco smoking. The prognostic factors were predicted using Cox’s proportional-hazards regression model, and the survival rate was calculated using Kaplan–Meier analysis. The median followup for all patients was 44months. The 5-year cumulative overall, disease-specific, and locoregional control survival rates were 61%, 62%, and 46%, respectively. Multivariate analysis showed that the lower level of nodal metastasis, advanced stage, tumor thickness >7mm, and treatment failures were independent risk factors of overall survival. Furthermore, history of alcohol drinking, lower level of nodal metastasis, advanced stage, poor cell differentiation, and treatment failures were independent predictors of poor disease-specific survival. However, we did not find any significant factor that affected locoregional recurrence. Due to the high frequencies of locoregional recurrence and second primary cancer, our findings emphasize that aggressive surgical excision, adjuvant treatments according to clinicopathological prognostic factors and close surveillance are important to the survival of OSCC patients in an area with a high prevalence of betel quid chewing and tobacco smoking.

Downregulation of CD9 protein expression is associated with aggressive behavior of oral squamous cell carcinoma - Corrected Proof

2010-01-11

Summary: Squamous cell carcinoma of the oral cavity (OSCC) is a malignancy characterized by a high degree of local aggression and metastasis to cervical lymph nodes. Tetraspanins are proteins with functional roles in a wide array of cellular processes and are reported to be associated with tumor progression. The present study investigated the expression of the CD9, CD37, CD63, CD81 and CD82 tetraspanins in OSCC using immunohistochemistry (IHC) and quantitative Real Time-PCR (qRT-PCR). Tissue microarray (TMA) analysis of samples from 179 cases of OSCC and 10 normal samples oral mucosa were evaluated immunomorphologically. We analyzed CD9 and CD82 expression by qRT-PCR in 66 OSCC cases and 4 normal samples of oral mucosa. Expression of CD63, CD37 and CD81 was not detected in the samples studied. CD82 was downregulated or negative in 127 of 179 (80%) specimens; no correlation was observed between CD82 expression, clinicopathological parameters, disease-free survival and 5-year overall survival. CD9 expression was downregulated or negative in 75 of 129 (42%) OSCC samples. Loss of CD9 expression in OSCC samples correlated with the incidence of lymph node metastasis (p=0.017). Disease-free survival and the 5-year overall survival of patients with downregulated or negative CD9 expression were significantly lower than in patients with positive CD9 expression (p=0.010 and p=0.071, respectively). No correlation was found between CD9 or CD82 expression and clinicopathological parameters by qRT-PCR. Our results suggest that the downregulation or lack of expression of the CD9 protein might indicate a more aggressive of OSCC.

The clinicopathological significance of the expression of Granzyme B in oral squamous cell carcinoma - Corrected Proof

2010-01-11

Summary: Granzyme B (GB) is a serine protease synthesized by activated cytotoxic T-lymphocytes and natural killer cells that induces neoplastic cells apoptosis. The expression of GB in the tumor microenvironment has been considered a favorable prognostic factor in several types of human cancers. Thus, the aim of this study was to evaluate the density of GB+ cells in samples of oral cavity squamous cell carcinoma (OCSCC), as well as their relationship with clinical and microscopic parameters. GB expression was analyzed in 55 cases of OCSCC and metastatic and non-metastatic lymph nodes by means of immunohistochemistry. The high density of GB+ cells demonstrated an association with the high percentage of Bax+ and annexin V+ neoplastic cells. In addition, the number of peritumoral GB+ cells was significantly higher in the OCSCC group without lymph node metastasis, when compared with the metastatic OCSCC group. Moreover, patients with OCSCC with a high density of peritumoral GB+ cells showed a longer survival time when compared with patients with a lower density of these cells. In lymph node tissues, the density of GB+ cells was significantly higher in non-metastatic lymph nodes than in metastatic lymph nodes. Our findings suggest that the increased of expression of GB in the tumor microenvironment of OCSCC and in lymph nodes may have beneficial effect against neoplastic cells, contributing to apoptosis of these cells and increased survival of patients.

Study of the length of hospital stay for free flap reconstruction of oral and pharyngeal cancer in the context of the new French casemix-based funding - Corrected Proof

2010-01-11

Summary: The French national health insurance reimbursement system has recently changed from a global hospital funding system to casemix-based funding. The authors studied the factors likely to influence the length of hospital stay for free flap reconstructions after surgery for cancers of the oral cavity or pharynx.Data concerning 207 oral cavity or pharynx free flap reconstructions were extracted from a prospective registration. Lengths of hospital stay were compared by an analysis of variance F test or a nonparametric Kruskal–Wallis test, and transfusion rates were compared by Chi-square test or Fisher’s exact test, as appropriate.The median length of hospital stay was 24days (range: 7–145days). Length of hospital stay was significantly longer according to the type of flap (p<0.005), in N2–N3 patients (p<0.02), a PINI score more than 10, a 3–4 American Society of Anesthesiologists (ASA) score, the presence of a tracheotomy and in patients requiring transfusion (p<0.0001).As the nodal status, the American Society of Anesthesiologists (ASA) score of the patient, the need of tracheotomy and the type of flap cannot be corrected, the management of preoperative haemoglobin and nutritional status are the sole factors which can improve the length of hospital stay. In the context of the new casemix-based funding, this study raises the problem of harvesting of the fibula flap, management of preoperative haemoglobin and nutritional status.

Study of FHIT and WWOX expression in mucoepidermoid carcinoma and adenoid cystic carcinoma of salivary gland - Corrected Proof

2010-01-11

Abstract: Mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC) are salivary gland neoplasms with divergent morphological features and clinical behavior. ACC is a basaloid tumor whereas MEC is a glandular epithelial neoplasm. FHIT and WWOX are tumor suppressor genes that encompass the FRA3B and FRA16D fragile sites at chromosomes 3p14.2 and 16q23.3, respectively. In previous studies, we have shown concordant loss of Fhit and Wwox expression in breast cancer, with significantly more frequent loss in cancers of basal-like phenotype. To determine if there is a similar association in salivary gland neoplasms, we designed a study of MEC and ACC of salivary gland on tissue microarrays (TMA). TMAs were constructed from 25 MEC and 19 ACC of salivary gland. Fhit and Wwox protein expression was assessed by immunohistochemical staining of cores on TMAs. Correlations among immunohistochemical markers and histological type were determined by statistical analyses. Significantly reduced Fhit and Wwox expression was observed in ACC (p=0.002 and p<0.001, respectively). The results suggest that, as for breast cancer, loss of Fhit and Wwox expression might have a role in the pathogenesis of basaloid differentiation in salivary gland neoplasms; alternatively, differences in chromatin structure at chromosome fragile regions might make fragile genes more accessible to DNA damage and rearrangement early during preneoplastic stages of basaloid cancers. Studies of basaloid tumors of other organ systems may show similar results and these findings may have implications for treatment modalities designed for basal-like tumors.

Overexpression of Id-1 is associated with tumor angiogenesis and poor clinical outcome in oral squamous cell carcinoma - Corrected Proof

2010-01-07

Summary: We analyzed the expression of Id-1 in oral squamous cell carcinoma (OSCC) immunohistochemically, and investigated the association of Id-1 expression with tumor angiogenesis and clinical prognosis. Overexpression of Id-1 protein was found in 83 out of 128 cases (64.8%). The expression of Id-1 was significantly associated with tumor size (p=0.013), lymph node metastasis (p=0.001), tumor stage (p=0.031) and tumor recurrence (p=0.003). Moreover, Id-1 expression was significantly correlated with intratumoral microvessel density (MVD) (r=0.223, p=0.011). The results suggest that overexpression of Id-1 was correlated with tumor angiogenesis and poor clinical outcome.

Inhibition of tumorigenicity and enhancement of radiochemosensitivity in head and neck squamous cell cancer-derived ALDH1-positive cells by knockdown of Bmi-1 - Corrected Proof

2009-12-28

Summary: Bmi-1, a member of the Polycomb family of transcriptional repressors, is essential for maintaining the self-renewal abilities of adult stem cells. Bmi-1 has been demonstrated to play a role in tumorigenesis in head and neck squamous cell carcinomas (HNSCCs). A recent study has further suggested that ALDH1 may be considered to be a putative marker for HNSCC-derived cancer stem cells. However, the role that Bmi-1 plays in HNSCC-derived ALDH1-positive cells (HNSCC-ALDH1+) has yet to be determined. In this study, we demonstrated that HNSCC-ALDH1+ cells possess tumor initiating properties, are capable of self-renewal, and express higher levels of Bmi-1 as compared to HNSCC-ALDH1− cells. To further explore the functional role of Bmi-1 in HNSCC-ALDH1+ cells, we used a lentiviral vector expressing shRNA to knock down Bmi-1 expression (sh-Bmi-1) in HNSCC-ALDH1+ cells. Silencing of Bmi-1 significantly enhanced the sensitivity of HNSCC-ALDH1+ cells to chemoradiation and increased the degree of chemoradiation-mediated apoptosis that occurred. Importantly, knockdown of Bmi-1 increased the effectiveness of radiotherapy and led to the inhibition of tumor growth in nude mice transplanted with HNSCC-ALDH1+ cells. Kaplan–Meier survival analysis indicated that the mean survival rate of HNSCC-ALDH1+ tumor-bearing immunocompromised mice treated with radiotherapy was significantly improved by treatment with sh-Bmi-1 as well. In summary, these results suggest that Bmi-1 is a potential target for increasing the sensitivity of HNSCC cancer stem cells to chemoradiotherapy.

Anti-invasion and anti-tumor growth effect of doxycycline treatment for human oral squamous-cell carcinoma – In vitro and in vivo studies - Corrected Proof

Ling-Chang Shen, Yuk-Kwan Chen, Li-Min Lin, Shyh-Yu Shaw — 2009-12-28

Summary: Regional lymph node and distant organ metastasis of oral squamous-cell carcinoma (OSCC) has been associated with increased production of matrix metalloproteases (MMPs), and scientific data showed that doxycycline (Dox) could down-regulate the expression of MMPs. The objective of this study was to evaluate the effect of Dox on the expression of MMPs in vitro using the SCC-15 cell line and in vivo SCC-15 xenografted nude mice. SCC-15 cells maintained under distinct culture conditions expressed high levels of pro-MMP-2 and pro-MMP-9; however, as determined by zymography and Western blot analysis, Dox significantly reduced the production of pro-MMP-2 and pro-MMP-9 after 24h of treatment in a dose-dependent manner (2.5–40μg/ml). Dox (10μg/ml) decreased the expression of MMP-9 mRNA but did not alter the level of MMP-2 mRNA after 24h of treatment. In addition, this drug significantly inhibited the invasive and migration activities of SCC-15 cells in vitro (>75% inhibition at 10μg/ml). On the other hand, daily administration of Dox (3mg/mice) restrained tumor growth in SCC-15 xenografted nude mice, with an inhibition rate of 85.6%. Compared with the control group (treated with normal saline), MMP-9 mRNA levels in the fresh tumor tissue decreased upon Dox treatment (P<0.01) while MMP-2 mRNA levels were unchanged. In conclusion, reduced expression of MMP-9 at the transcriptional level and MMP-2 at the post-transcriptional level caused by Dox was found to be associated with decreased invasion of oral SCC in vitro. Moreover, Dox exerted a significant suppressive effect on tumor growth in an in vivo nude mice model. Taken together, these results, to our knowledge, may first imply that Doxycycline has an adjuvant therapeutic effect on OSCC that is associated with inhibition of MMPs expression.