Patterns of cancer cell sphere formation in primary cultures of human oral tongue squamous cell carcinoma and neck nodes

Mapping the lymph node metastasis landscape: A bibliometric Odyssey of papillary thyroid carcinoma publications (2012-2022)

Objective

Lymph node metastasis in papillary thyroid carcinoma (PTC) has become an area of great interest in the study of thyroid diseases. The aim of this study was to elucidate the research trends and impact of lymph node metastasis of PTC in the study of thyroid diseases through a comprehensive bibliometric analysis.

Methods

We conducted an extensive bibliometric review of the literature on lymph node metastasis in PTC using the Web of Science Core Database (WOSCC), which included approximately 3292 publications from 2012 to 2022. Data analysis and visualization were performed, using advanced bibliometric tools including VOSviewer, CiteSpace, and bibliometrix R software packages.

Results

A total of 3292 publications from 81 one countries were identified. The analysis showed a pattern of growth in the number of publications per year from 2012 to 2022, with China having the highest number of papers. Outstanding contributions were made by China, Korea, USA, Italy and Japan, with Thyroid being the most important journal. The author who published the most papers was Jingqiang Zhu. The institutions that published the most papers were Shanghai Jiao Tong University and Yonsei University. The analysis found that prognosis, recurrence, and ultrasound were the keywords with the highest frequency of occurrence in addition to those related to the title of this article.

Conclusion

Our bibliometric analysis outlines the current state of research on lymph node metastasis in PTC, highlighting significant contributions, trends, and future research directions.

Panoramic view of key cross-talks underpinning the oral squamous cell carcinoma stemness - unearthing the future opportunities

The clinical management of oral cancer is often frequented with challenges that arise from relapse, recurrence, invasion and resistance towards the cornerstone chemo and radiation therapies. The recent conceptual advancement in oncology has substantiated the role of cancer stem cells (CSC) as a predominant player of these intricacies. CSC are a sub-group of tumor population with inherent adroitness to self-renew with high plasticity. During tumor evolution, the structural and functional reprogramming persuades the cancer cells to acquire stem-cell like properties, thus presenting them with higher survival abilities and treatment resistance. An appraisal on key features that govern the stemness is of prime importance to confront the current challenges encountered in oral cancer. The nurturing niche of CSC for maintaining its stemness characteristics is thought to be modulated by complex multi-layered components encompassing neoplastic cells, extracellular matrix, acellular components, circulatory vessels, various cascading signaling molecules and stromal cells. This review focuses on recapitulating both intrinsic and extrinsic mechanisms that impart the stemness. There are contemplating evidences that demonstrate the role of transcription factors (TF) in sustaining the neoplastic stem cell's pluripotency and plasticity alongside the miRNA in regulation of crucial genes involved in the transformation of normal oral mucosa to malignancy. This review illustrates the interplay between miRNA and various known TF of oral cancer such as c-Myc, SOX, STAT, NANOG and OCT in orchestrating the stemness and resistance features. Further, the cross-talks involved in tumor micro-environment inclusive of cytokines, macrophages, extra cellular matrix, angiogenesis leading pathways and influential factors of hypoxia on tumorigenesis and CSC survival have been elucidated. Finally, external factorial influence of oral microbiome gained due to the dysbiosis is also emphasized. There are growing confirmations of the possible roles of microbiomes in the progression of oral cancer. Given this, an attempt has been made to explore the potential links including EMT and signaling pathways towards resistance and stemness. This review provides a spectrum of understanding on stemness and progression of oral cancers at various regulatory levels along with their current therapeutic knowledge. These mechanisms could be exploited for future research to expand potential treatment strategies.

Utility of CD44/CD24 in the Outcome and Prognosis of Oral Squamous Cell Carcinoma: A Systematic Review

Cancer stem cells (CSCs) are characterized by their capacity for self-renewal and differentiation. CD44 and CD24 are two commonly used markers to identify these CSCs. Despite the enormous amount of data available in the literature, their specificity and coexistence remain elusive in oral squamous cell carcinoma (OSCC). In the present review, we aimed to assess the diagnostic utility of the CD44/CD24 combination in tumor development and metastasis in OSCC. Two investigators independently performed a systematic search to identify all the relevant studies from various electronic databases. Out of 694 articles, 9 were found eligible for further evaluation. Details including the number of patients, gender, site, tobacco and alcohol consumption, histological stage, CD24 expression, CD44 expression, CD44/CD24 expression, nodal status, disease-free survival, and overall survival were extracted. CD44+CD24- expression was noted in 35/207 (16.9%) cases, CD44+CD24+ in 53/207 (25.6%) cases, CD44-CD24- in 49/207 subjects (23.67%), and CD44-/CD24+ in 70/207 (33.81%) cases. CD44 or CD24 or their co-expression did not correlate with the disease-free survival rate, and double negatives (CD44-/CD24-) demonstrated a higher overall survival than other immunotypes. CD44/CD24 profile may be used on small incisional biopsies to predict the outcome and treatment planning. This finding may help in developing new therapeutic targets to suppress cancer metastasis and provide a better long-term prognosis for patients diagnosed with OSCC.

Eliminating Cancer Stem-Like Cells in Oral Cancer by Targeting Elementary Signaling Pathways

Oral cancer is a heterogeneous, aggressive, and complex entity. Current major treatment options for the disease are surgery, chemo, and/or radiotherapy either alone or in combination with each other. Each treatment method has its own limitations such as a significant journey with deformities and a protracted rehabilitation process leading to loss of self-esteem, loss of tolerance, and therapeutic side effects. Conventional therapies are frequently experienced with regimen resistance and recurrence attributed to the cancer stem cells (CSCs). Given that CSCs exert their tumorigenesis by affecting several cellular and molecular targets and pathways an improved understanding of CSCs' actions is required. Hence, more research is recommended to fully understand the fundamental mechanisms driving CSC-mediated treatment resistance. Despite the difficulties and disagreements surrounding the removal of CSCs from solid tumors, a great amount of knowledge has been derived from the characterization of CSCs. Various efforts have been made to identify the CSCs using several cell surface markers. In the current review, we will discuss numerous cell surface markers such as CD44, ALDH1, EPCAM, CD24, CD133, CD271, CD90, and Cripto-1 for identifying and isolating CSCs from primary oral squamous cell carcinoma (OSCC). Further, a spectrum of embryonic signaling pathways has been thought to be the main culprit of CSCs' active state in cancers, resulting in conventional therapeutic resistance. Hence, we discuss the functional and molecular bases of several signaling pathways such as the Wnt/beta;-catenin, Notch, Hedgehog, and Hippo pathways and their associations with disease aggressiveness. Moreover, numerous inhibitors targeting the above mentioned signaling pathways have already been identified and some of them are already undergoing clinical trials. Hence, the present review encapsulates the characterization and effectiveness of the prospective potential targeted therapies for eradicating CSCs in oral cancers.

Inhibition of Bruton's tyrosine kinase as a therapeutic strategy for chemoresistant oral squamous cell carcinoma and potential suppression of cancer stemness

Locally advanced oral squamous cell carcinoma (OSCC) requires multimodal therapy, including surgery and concurrent chemoradiotherapy (CCRT). CCRT-resistant and recurrent cancer has a poor prognosis. We investigated the effects of Bruton's tyrosine kinase (BTK) on CCRT-resistant OSCC tissues. The effect of ibrutinib, a first-in-class BTK inhibitor, was tested on stem cell-like OSCC tumorspheres. A tissue array was constructed using tissue samples from 70 patients with OSCC. Human OSCC cell lines, SAS, TW2.6 and HSC-3, were examined. Wound healing, Matrigel invasion, and tumorsphere formation assays, as well as immunofluorescence analysis and flow cytometry, were used to investigate the effects of BTK knockdown (shBTK), ibrutinib, cisplatin, and ibrutinib/cisplatin combination on OSCC cells. We demonstrated that BTK was aberrantly highly expressed in the clinical CCRT-resistant OSCC tissue array, which resulted in poor overall survival in our local Tri-Service General Hospital and freely accessible TCGA OSCC cohorts. shBTK significantly downregulated the stemness markers Nanog, CD133, T cell immunoglobulin-3 (TIM-3), and Krüppel-like factor 4 (KLF4) in SAS tumorspheres and attenuated OSCC cell migration and colony formation. Ibrutinib reduced the number of aldehyde dehydrogenase (ALDH)-rich OSCC cells and reduced tumorsphere formation, migration, and invasion in a dose-dependent manner. Compared with ibrutinib or cisplatin monotherapy, the ibrutinib/cisplatin combination significantly reduced the formation of ALDH + OSCC tumorspheres and enhanced apoptosis. These results demonstrate that ibrutinib effectively inhibits the CSCs-like phenotype of OSCC cells through dysregulation of BTK/CD133 signaling. The ibrutinib/cisplatin combination may be considered for future clinical use.

HPV+ve/-ve oral-tongue cancer stem cells: A potential target for relapse-free therapy

The tongue squamous cell carcinoma (TSCC) is a highly prevalent head and neck cancer often associated with tobacco and/or alcohol abuse or high-risk human papillomavirus (HR-HPV) infection. HPV positive TSCCs present a unique mechanism of tumorigenesis as compared to tobacco and alcohol-induced TSCCs and show a better prognosis when treated. The poor prognosis and/or recurrence of TSCC is due to presence of a small subpopulation of tumor-initiating tongue cancer stem cells (TCSCs) that are intrinsically resistant to conventional chemoradio-therapies enabling cancer to relapse. Therefore, targeting TCSCs may provide efficient therapeutic strategy for relapse-free survival of TSCC patients. Indeed, the development of new TCSC targeting therapeutic approaches for the successful elimination of HPV+ve/-ve TCSCs could be achieved either by targeting the self-renewal pathways, epithelial mesenchymal transition, vascular niche, nanoparticles-based therapy, induction of differentiation, chemoradio-sensitization of TCSCs or TCSC-derived exosome-based drug delivery and inhibition of HPV oncogenes or by regulating epigenetic pathways. In this review, we have discussed all these potential approaches and highlighted several important signaling pathways/networks involved in the formation and maintenance of TCSCs, which are targetable as novel therapeutic targets to sensitize/eliminate TCSCs and to improve survival of TSCC patients.

Evaluation of CD24 and CD44 as cancer stem cell markers in squamous cell carcinoma and epithelial dysplasia of the oral cavity by q- RT-PCR

BACKGROUND

Squamous cell carcinoma (SCC) is the most common cancer of the oral cavity and may be preceded by dysplastic epithelial lesion. Oral SCC (OSCC) contains a rare subset of cancer cells with self-renewal ability, termed as cancer stem cells (CSCs). CD24 and CD44 as CSC markers are cell surface glycoproteins. These markers contribute to the onset, maintenance, and extension of tumor growth, as well as angiogenesis. In the present study, these two markers were simultaneously evaluated to provide a specific phenotype for carcinogenesis process in oral cavity.

MATERIALS AND METHODS

In this analytical-cross-sectional study, the expression of CD24 and CD44 genes was evaluated in 45 OSCCs (20 low-grade and 25 high-grade) and 15 oral epithelial dysplasia specimens by real-time quantitative reverse transcription polymerase chain reaction. Kruskal-Wallis and Mann-Whitney U-test, Kendall, and Spearman tests were used for statistical analysis. The significance level was considered <0.05.

RESULTS

High expression of both markers genes was reported in two-thirds of samples. There was no significant difference between studied groups in gene expression of CD24 and CD44 whereas statistically significant association between CD24 and CD44 was observed in all three groups. This correlation was more significant in OSCC groups (P < 0.001).

CONCLUSION

High expression of CSC markers in OSCC and oral epithelial dysplasia revealed the importance of accurate examination of dysplastic lesions with high expression of these markers and the possibility of malignant transformation. Regarding a significant association of two markers, further studies are necessary to provide a specific phenotype (CD44 high CD24 high) for these lesions.

Cancer stem cells and oral cancer: insights into molecular mechanisms and therapeutic approaches

Cancer stem cells (CSCs) have been identified as a little population of cancer cells, which have features as the same as the cells normal stem cells. There is enough knowledge of the CSCs responsibility for metastasis, medicine resistance, and cancer outbreak. Therefore, CSCs control possibly provides an efficient treatment intervention inhibiting tumor growth and invasion. In spite of the significance of targeting CSCs in treating cancer, few study comprehensively explored the nature of oral CSCs. It has been showed that oral CSCs are able to contribute to oral cancer progression though activation/inhibition a sequences of cellular and molecular pathways (microRNA network, histone modifications and calcium regulation). Hence, more understanding about the properties of oral cancers and their behaviors will help us to develop new therapeutic platforms. Head and neck CSCs remain a viable and intriguing option for targeted therapy. Multiple investigations suggested the major contribution of the CSCs to the metastasis, tumorigenesis, and resistance to the new therapeutic regimes. Therefore, experts in the field are examining the encouraging targeted therapeutic choices. In spite of the advancements, there are not enough information in this area and thus a magic bullet for targeting and eliminating the CSCs deviated us. Hence, additional investigations on the combined therapies against the head and neck CSCs could offer considerable achievements. The present research is a review of the recent information on oral CSCs, and focused on current advancements in new signaling pathways contributed to their stemness regulation. Moreover, we highlighted various therapeutic approaches against oral CSCs.

An Updated Review of Oral Cancer Stem Cells and Their Stemness Regulation

Cancer stem cells (CSCs; also known as tumor-initiating cells) are a small population of cancer cells that retain characteristics similar to those of normal stem cells. CSCs are known to be responsible for metastasis, drug resistance, and cancer recurrence. Thus, controlling CSCs may provide an effective therapeutic intervention that inhibits tumor growth and aggressiveness. Despite the importance of targeting CSCs in cancer therapy, the detailed nature of oral CSCs remains underexplored. This article reviews the current understanding of oral CSCs, with emphasis on recent advances in novel signaling pathways involved in their stemness regulation.

CD24 blunts oral squamous cancer development and dampens the functional expansion of myeloid-derived suppressor cells

CD24 expression has been implicated in the oncogenesis of multiple types of cancer and high tumor expression is considered a poor prognosis factor; however, the role of CD24 in oral cancer progression is unknown. Unlike other cancer types, we found that higher CD24 levels in human oral cancers are correlated to lower clinical stage and better overall survival. We then dissected the role of CD24 and mechanisms in oral cancer pathogenesis in mice using a genetic strategy and demonstrated that CD24 deficiency increased the oral cavity tumor burden in response to the carcinogen 4-nitroquioline 1-oxide (4-NQO). Immune profile analysis showed a significant expansion as well as increased suppressive function of myeloid-derived suppressor cells (MDSCs) in CD24^-/- mice, but no apparent impairment in T cells, B cells, or dendritic cells. Further, studies with an orthotopically transplanted syngeneic squamous carcinoma model in the tongue of CD24^-/- and CD24^+/- mice confirmed the protective roles of CD24 against cancer. Moreover, the difference in tumor growth between CD24^-/- and CD24^+/- mice was blunted by immunodepletion of MDSCs. We conclude that CD24 expression impedes MDSC expansion and function, and thus slows oral cancer oncogenesis. This study is the first to examine the role of CD24 in a de novo oral cancer model, and it highlights the need to consider the immune regulatory roles of CD24 in the development of CD24-targeted therapy for cancer.

Human lung-derived mesenchymal stem cell-conditioned medium exerts in vitro antitumor effects in malignant pleural mesothelioma cell lines

Background

The soluble factors secreted by mesenchymal stem cells are thought to either support or inhibit tumor growth. Herein, we investigated whether the human lung-derived mesenchymal stem cell-conditioned medium (hlMSC-CM) exerts antitumor activity in malignant pleural mesothelioma cell lines H28, H2052 and Meso4.

Methods

hlMSC-CM was collected from the human lung-derived mesenchymal stem cells. Inhibition of tumor cell growth was based on the reduction of cell viability and inhibition of cell proliferation using the XTT and BrdU assays, respectively. Elimination of tumor spheroids was assessed by the anchorage-independent sphere formation assay. The cytokine profile of hlMSC-CM was determined by a chemiluminescence-based cytokine array.

Results

Our data showed that hlMSC-CM contains a broad range of soluble factors which include: cytokines, chemokines, hormones, growth and angiogenic factors, matrix metalloproteinases, metalloproteinase inhibitors and cell–cell mediator proteins. The 48- and 72-hour hlMSC-CM treatments of H28, H2052 and Meso4 cell lines elicited significant decreases in cell viability and inhibited cell proliferation. The 72-hour hlMSC-CM incubation of H28 cells completely eliminated the drug-resistant sphere-forming cells, which is more potent than twice the half maximal inhibitory concentration of cisplatin.

Conclusions

Our findings indicate that the cell-free hlMSC-CM confers in vitro antitumor activities via soluble factors in the tested mesothelioma cells and, hence, may serve as a therapeutic tool to augment the current treatment strategies in malignant pleural mesothelioma.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0282-7) contains supplementary material, which is available to authorized users.