SIRT3 and cancer: Tumor promoter or suppressor?

AbstractSirtuins (SIRT1–7), the mammalian homologues of the Sir2 gene in yeast, have emerging roles in age-related diseases, such as cardiac hypertrophy, diabetes, obesity, and cancer. However, the role of several sirtuin family members, including SIRT1 and SIRT3, in cancer has been controversial. The aim of this review is to explore and discuss the seemingly dichotomous role of SIRT3 in cancer biology with particular emphasis on its potential role as a tumor promoter and tumor suppressor. This review will also discuss the potential role of SIRT3 as a novel therapeutic target to treat cancer

The anticariogenic effect of xylitol on seven Streptococcus mutans strains

Introduction: Xylitol can affect caries-inducing bacteria; however, different Streptococcus mutans strains might respond differently. Aim: To investigate the effect of xylitol on biofilm formation and metabolic activity of seven S. mutans strains. Methods: Seven S. mutans strains (UA159, A32-2, NG8, 10449, UA130, LM7, and OMZ175) were inoculated into 96-well microtiter plates and were tested with various xylitol concentrations (0.0, 0.0016, 0.0031, 0.0063, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 g/mL) for inhibition of biofilm formation and bacterial metabolic activity by recording absorbance values. Lactate dehydrogenase and extracellular polysaccharide assays were conducted at 0.0, 0.1, 0.2, 0.4, and 0.8 g xylitol/mL. Data were analyzed by one-way analysis of variance, Tukey’s, paired t, and LSD tests at 0.05 significance level. Results: Xylitol produced a significant decrease in bacterial biofilm formation compared to controls at 0.4 g/mL, with almost complete lack of biofilm formation at 0.8 g/mL. This was consistent with metabolic activity which demonstrated a significant activity reduction occurring for all strains at 0.4 g/mL, and a complete lack of activity at 0.8 g/mL for all seven strains. There was a trend for lower LDH and EPS production with the increase in xylitol concentration especially with UA159, UA130, and NG8. Conclusion: Xylitol has a clear anticariogenic effect on S. mutans which was slightly different depending on the tested strain confirming that the benefit of xylitol might vary from one patient to another. The effect is more apparent at concentrations of 0.4 g/mL and higher

Awareness and attitude toward using dental magnification among dental students and residents at King Abdulaziz University, Faculty of Dentistry

Abstract Background The authors conducted a study aimed to assess the awareness and attitude among dental students and residents at King Abdulaziz University, Faculty of Dentistry (KAUFD) toward using dental magnification. Methods An e-questionnaire was formulated then sent to dental students and residents (n = 651). The questionnaire included questions that assessed both the awareness and attitude toward using dental magnification. Data were analyzed using IBM SPSS version 22. The chi-square test was used to establish relationships between categorical variables. Results The response rate was 69.7 % (n = 454). Of those, 78.1 % did not use magnification during dental procedures. However, 81.8 % agreed that dental magnification could enhance the accuracy and quality of their dental work. Thus, 91.6 % thought it would be useful in endodontics and 46.3 % voted for surgery. Of the 21.9 % that used magnification, dental loupes were mostly used, 55.9 %. The majority (59.4 %) of the participants believed that using dental magnification should be introduced by faculty beginning in Year I of dental school. Conclusions Among our respondents, most of the undergraduate students did not use dental magnification nor attended courses in the use of dental magnifications. However, most of the students were aware of its significance in improving the accuracy and quality of their work.http://deepblue.lib.umich.edu/bitstream/2027.42/134609/1/12903_2016_Article_254.pd

Sirtuin-3 (SIRT3) and the Hallmarks of Cancer

Sirtuins (SIRT1-SIRT7), the mammalian homologs of the silent information regulator 2 (Sir2) in Saccharomyces cerevisiae, have been a major focus of study in the scientific community this past decade because of their emerging role in cancer biology and other age-related diseases. Emerging functions for this unique family of enzymes include roles in genomic stability, angiogenesis, metabolism, and anoikis. Here, we review recent developments on the role of sirtuins in cancer with a particular focus on SIRT3 and its role in the hallmarks of cancer and as a potential drug target for cancer treatment

Sirtuin-3 (SIRT3) and the Hallmarks of Cancer

Sirtuins (SIRT1-SIRT7), the mammalian homologs of the silent information regulator 2 (Sir2) in Saccharomyces cerevisiae, have been a major focus of study in the scientific community this past decade because of their emerging role in cancer biology and other age-related diseases. Emerging functions for this unique family of enzymes include roles in genomic stability, angiogenesis, metabolism, and anoikis. Here, we review recent developments on the role of sirtuins in cancer with a particular focus on SIRT3 and its role in the hallmarks of cancer and as a potential drug target for cancer treatment

A Novel Sirtuin-3 Inhibitor, LC-0296, Inhibits Cell Survival and Proliferation, and Promotes Apoptosis of Head and Neck Cancer Cells.

BackgroundThe survival rate of patients with head and neck squamous cell carcinoma (HNSCC) stands at approximately 50% and this has not improved in decades. This study developed a novel sirtuin-3 (SIRT3) inhibitor (LC-0296) and examined its role in altering HNSCC tumorigenesis.Materials and methodsThe effect of the SIRT3 inhibitor, LC-0296, on cell survival, proliferation, and apoptosis, and reactive oxygen species levels in HNSCC cells were studied.ResultsLC-0296 reduces cell proliferation and promotes apoptosis of HNSCC cells but not of normal human oral keratinocytes. This inhibitory effect is mediated, in part, via modulation of reactive oxygen species levels. Additionally, LC-0296 works synergistically to increase the sensitivity of HNSCC cells to radiation and cisplatin treatment.ConclusionDevelopment of novel SIRT3 inhibitors, such as LC-0296, might enable the development of new targeted therapies to treat and improve the survival rate of patients with head and neck cancer

Assessment of prevalence of anatomical variations and pathosis of the maxillary sinuses using cone-beam computed tomography in a sample of the population of Saudi Arabia

Background: Cone-beam computed tomography (CBCT) technology has been a useful tool for decreasing dental treatment complications and ensuring more predictable treatment outcomes. Objectives: This study aimed to assess the prevalence of maxillary sinuses status in regard to anatomical variations and pathosis using CBCT as a diagnostic tool, in asymptomatic patients who are willing to receive dental implants at King Abdulaziz University Dental Hospital in Jeddah, Saudi Arabia. Materials and Methods: Both sinuses in 263 patients (140 females and 96 males) were evaluated using iCAT Classic scanner to acquire the total of 526 CBCT images. Two calibrated dental radiology consultants evaluated the CBCT of the maxillary sinuses images using the Vision software (Imaging Sciences International, Hatfield, PA, USA) for the following finding: number of teeth in intimate relation with the maxillary sinus and the presence of septa (as anatomical variations) and the presence, extent, and configuration of mucosal thickening (MT) as sign of pathosis (mucositis). Results: The highest prevalence of dental proximity to the sinus wall was between the first left premolars and the anterior sinus wall (57.14%) followed by the second right premolars (56.14%). The presence of septa in both right and left maxillary sinuses was 54.37% and 57.41%, respectively. The prevalence of sinus pathosis was 52.7%. Interestingly, 87.07% of the MT cases were due to nonodontogenic origin compared to 12.93% of odontogenic-related pathosis. Conclusions: Preoperative radiographic assessment using CBCT is highly recommended before dental implant placement in our population due to the high anatomical variations and pathosis rates, to allow proper assessment and diagnosis of maxillary sinus disease, if present. The assessment of maxillary sinus disease before surgical intervention will provide a higher standard of care and decrease the risk of complications and failures of dental implants

Sirtuin-3 (SIRT3), a novel potential therapeutic target for oral cancer

BACKGROUND: Several sirtuin family members (SIRT1-7), which are evolutionarily conserved NAD-dependent deacetylases, play an important role in carcinogenesis. However, their role in oral cancer has not yet been investigated. Therefore, the objective of this study was to investigate whether sirtuins play a role in oral cancer carcinogenesis. METHODS: The expression levels of all sirtuins in several oral squamous cell carcinoma (OSCC) cell lines were compared with normal human oral keratinocytes and observed that SIRT3 was highly expressed. Therefore, tissue microarrays were used to evaluate the clinical relevance of this overexpression. SIRT3 down-regulation in OSCC cell proliferation and survival was investigated and analyzed by using cell-proliferation and cell-viability assays. Ionizing radiation and cisplatin were used to investigate whether SIRT3 down-regulation could increase the sensitivity of OSCC to both treatments. To further assess the in vivo role of SIRT3 in OSCC carcinogenesis, a floor-of-mouth oral cancer murine model was used to study the effect of SIRT3 down-regulation on OSCC tumor growth in immunodeficient mice. RESULTS: The current results demonstrated for the first time that SIRT3 is overexpressed in OSCC in vitro and in vivo compared with other sirtuins. Down-regulation of SIRT3 inhibited OSCC cell growth and proliferation and increased OSCC cell sensitivity to radiation and cisplatin treatments in vitro. SIRT3 down-regulation also reduced tumor burden in vivo. CONCLUSIONS: The current investigation revealed a novel role for SIRT3 in oral cancer carcinogenesis as a promoter of cell proliferation and survival, thus implicating SIRT3 as a new potential therapeutic target to treat oral cancer. Cancer 2011. © 2010 American Cancer Society.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84409/1/25676_ftp.pd

The knowledge and attitude of general dental practitioners toward the proper standards of care while managing endodontic patients in Saudi Arabia

Aim: The aim of this study was to assess the knowledge and attitude of general dental practitioners (GDPs) toward performing the proper standards of care while managing patients undergoing endodontic treatment in Saudi Arabia. Materials and Methods: An e-questionnaire was distributed among GDPs in Saudi Arabia (n = 650). The e-questionnaire questions covered the assessment of knowledge, attitude, and performance of GDPs toward practicing the proper standards of endodontic treatment in their clinic. Data were analyzed using SPSS version 22, and the relationships between categorical variables were established using Chi-square test. Results: Most of the participants reported obtaining full medical history before root canal treatment (RCT, 82.3%; P < 0.05). However, only 12.2% of the participants regularly measure the blood pressure for their patients before starting RCT. Only 56.3% of the participated dentists are applying rubber dam isolation during RCT, while 24.2% believe that partial isolation is sufficient for such a procedure (P < 0.05). Furthermore, 42.8% of the surveyed GDPs use cold test to confirm the endodontic diagnosis, while 55.5% think that percussion is a reliable method for diagnosis (P < 0.05). Surprisingly, 37.3% of the dentists still prefer leaving the tooth open for pain relief and drainage in abscess cases. Finally, only 28.7% of the participants mentioned performing regular follow-up after RCT. Conclusions: Our data show a clear deficiency in the standards of care provided by GDPs when performing RCT in Saudi Arabia. We hope that this publication will help highlight key areas where lack of knowledge and poor attitude exist while performing RCT by the GDPs in Saudi, thereby helping to raise treatment standards and improve treatment outcomes