Lentiviral vector-based therapy in head and neck cancer (Review)

Smokeless tobacco and oral cancer in the Middle East and North Africa: A systematic review and meta-analysis

INTRODUCTION

Cancer of the oral cavity is regarded lethal with a fairly low mean 5-year survival rate. The current systematic review and meta-analysis is the first of its kind to examine, if the evidence from the Middle East and North African region indicates an association between oral cancer and tobacco; and evaluates the quality of the evidence that portrays this relationship.

METHODS

A search for articles was carried out in October 2017 and then cross-checked at the end of June 2018 using Medline, Web of Science, CINAHL, and Cochrane databases. Retrieved articles were later subjected to eligibility criteria. The search was not limited to any particular research design adopted by the investigators. However, dissertations, theses and opinion-based reviews generated from the search were excluded during the screening of titles and abstracts. Quality of included studies was determined objectively (Newcastle Ottawa Scale) and subjectively. Revman (Version 5.3) was used for conducting the meta-analysis.

RESULTS

Six studies satisfied the selection criteria of the current review. The New Castle Ottawa evaluation scale suggested that the three cross-sectional studies and the three case-control studies included in the current review were of relatively low to moderate quality. All included studies explored the association of only one form of smokeless tobacco, i.e. shammah. Three case-control studies revealed a pooled estimate odds ratio of 38.74 (95% CI: 19.50–76.96), indicating that the odds for the occurrence of oral cancer among shammah users were nearly 39 times higher compared to the non-users.

CONCLUSIONS

Shammah is a potential risk factor for oral cancer; thus, it is necessary that public health practitioners design and implement effective strategies to prevent the abuse of shammah.

A simple and cost-saving phenotypic drug susceptibility testing of HIV-1

It is essential to monitor the occurrence of drug-resistant strains and to provide guidance for clinically adapted antiviral treatment of HIV/AIDS. In this study, an individual patient's HIV-1 pol gene encoding the full length of protease and part of the reverse transcriptase was packaged into a modified lentivirus carrying dual-reporters ZsGreen and luciferase. The optimal coefficient of correlation between drug concentration and luciferase activity was optimized. A clear-cut dose-dependent relationship between lentivirus production and luciferase activity was found in the phenotypic testing system. Fold changes (FC) to a wild-type control HIV-1 strain ratios were determined reflecting the phenotypic susceptibility of treatment-exposed patient's HIV-1 strains to 12 HIV-1 inhibitors including 6 nucleoside reverse-transcriptase inhibitors (NRTIs), 4 non-nucleoside reverse transcriptase inhibitors (NNRTIs) and 2 protease inhibitors (PIs). Phenotypic susceptibility calls from 8 HIV-1 infected patients were consistent with 80-90% genotypic evaluations, while phenotypic assessments rectified 10-20% genotypic resistance calls. By a half of replacement with ZsGreen reporter, the consumption of high cost Bright-Glo Luciferase Assay is reduced, making this assay cheaper when a large number of HIV-1 infected individuals are tested. The study provides a useful tool for interpreting meaningful genotypic mutations and guiding tailored antiviral treatment of HIV/AIDS in clinical practice.

Targeting Head and Neck Cancer Stem Cells: Current Advances and Future Challenges

Cancer stem cells (CSCs), or tumor-initiating cells, comprise a subset of tumor cells with demonstrated ability for tumor growth, invasion, metastasis, and resistance to chemotherapy and radiation. Targeting of CSCs remains an attractive yet elusive therapeutic option, with the goal of increasing specificity and effectiveness in tumor eradication, as well as decreasing off-target or systemic toxicity. Research into further characterization and targeted therapy toward head and neck CSCs is an active and rapidly evolving field. This review discusses the current state of research into therapy against head and neck CSCs and future directions for targeted therapy.

TCAB1: a potential target for diagnosis and therapy of head and neck carcinomas

Background

WRAP53, including α, β and γ isoforms, plays an important role not only in the stability of p53 mRNA, but also in the assembly and trafficking of the telomerase holoenzyme. It has been considered an oncogene and is thought to promote the survival of cancer cells. The aim of this study was to detect the role of TCAB1 (except WRAP53α) in the occurrence and development of head and neck carcinomas.

Methods

Immunohistochemistry was used to detect the TCAB1 expression in clinical specimen sections and performed western blotting to check the TCAB1 expression levels in cell lines. TCAB1 was depleted using shRNA lentivirus and the knockdown efficiency was assessed using q-PCR and Western blotting. We performed CCK-8 assays and flow cytometry to check the cell proliferation potential and used the trans-well assay to test the invasion ability in vitro. Xenografts were used to detect the tumor formation potential in vivo. Moreover, we performed cDNA microarray to investigate the candidate factors involved in this process.

Results

We observed a notable overexpression of TCAB1 in head and neck carcinoma clinical specimens as well as in carcinoma cell lines. Knockdown of TCAB1 decreased the cellular proliferation potential and invasion ability in vitro. cDNA microarray analysis suggested the possible involvement of several pathways and factors associated with tumorigenesis and carcinoma development in the TCAB1-mediated regulation of cancers. Furthermore, the xenograft assay confirmed that the depletion of TCAB1 would inhibit tumor formation in nude mice. The immunohistochemistry results of the mice tumor tissue sections revealed that the cells in shTCAB1 xenografts showed decreased proliferation potential and increased apoptotic trend, meanwhile, the angiogenesis was inhibited in the smaller tumors form shTCAB1 cells.

Conclusions

Our study demonstrated that depletion of TCAB1 decreased cellular proliferation and invasion potential both in vitro and in vivo. The data indicated that TCAB1 might facilitate the occurrence and development of head and neck carcinomas. In future, TCAB1 might be useful as a prognostic biomarker or a potential target for the diagnosis and therapy of head and neck carcinomas.

Smokeless tobacco and oral cancer in South Asia: a systematic review with meta-analysis

Introduction. Smokeless tobacco is considered one of the major risk factors for oral cancer. It is estimated that over 90% of the global smokeless tobacco use burden is in South Asia. This paper aims to systematically review publications reporting epidemiological observational studies published in South Asia from 1984 till 2013. Methods. An electronic search in "Medline" and "ISI Web of Knowledge" yielded 734 publications out of which 21 were included in this review. All publications were assessed for quality using a standard quality assessment tool. Effect estimates (odds ratios (OR)) were abstracted or calculated from the given data. A random effects meta-analysis was performed to assess the risk of oral cancer with the use of different forms of smokeless tobacco. Results and Conclusion. The pooled OR for chewing tobacco and risk of oral cancer was 4.7 [3.1-7.1] and for paan with tobacco and risk of oral cancer was 7.1 [4.5-11.1]. The findings of this study suggest a strong causal link between oral cancer and various forms of smokeless tobacco. Public health policies in affected countries should consider SLT specific cessation programs in addition to campaigns and activities incorporated into smoking cessation programs.