Relevance of cancer initiating/stem cells in carcinogenesis and therapy resistance in oral cancer

CSChighE-cadherinlow immunohistochemistry panel predicts poor prognosis in oral squamous cell carcinoma

Identifying marker combinations for robust prognostic validation in primary tumour compartments remains challenging. We aimed to assess the prognostic significance of CSC markers (ALDH1, CD44, p75NTR, BMI-1) and E-cadherin biomarkers in OSCC. We analysed 94 primary OSCC and 67 metastatic lymph node samples, including central and invasive tumour fronts (ITF), along with clinicopathological data. We observed an increase in ALDH1+/CD44+/BMI-1- tumour cells in metastatic lesions compared to primary tumours. Multivariate analysis highlighted that elevated p75NTR levels (at ITF) and reduced E-cadherin expression (at the tumour centre) independently predicted metastasis, whilst ALDH1high exhibited independent predictive lower survival at the ITF, surpassing the efficacy of traditional tumour staging. Then, specifically at the ITF, profiles characterized by CSChighE-cadherinlow (ALDH1highp75NTRhighE-cadherinlow) and CSCintermediateE-cadherinlow (ALDH1 or p75NTRhighE-cadherinlow) were significantly associated with worsened overall survival and increased likelihood of metastasis in OSCC patients. In summary, our study revealed diverse tumour cell profiles in OSCC tissues, with varying CSC and E-cadherin marker patterns across primary tumours and metastatic sites. Given the pivotal role of reduced survival rates as an indicator of unfavourable prognosis, the immunohistochemistry profile identified as CSChighE-cadherinlow at the ITF of primary tumours, emerges as a preferred prognostic marker closely linked to adverse outcomes in OSCC.

Cancer stem cells in head and neck squamous cell carcinoma and its associated markers: A review

ABSTRACT

Evidences of the current research say that cancer is multifactorial with varied mechanisms of origin. Most theories evolve either intrinsic (genetic) or extrinsic factors like tobacco and alcoholism as the major cause of oral cancer in India. There is growing evidence that human papilloma virus may act as a co-carcinogen, along with tobacco, in the causation of cancers. The cells being triggered by the agents may be somatic (differentiated functional cell) or a normal stem cell with multipotency or even the transient proliferative cells derived from the stem cells. These stem cells possess several features like slow cell cycle, ability to extrude chemotherapeutic drugs, exhibit epithelial mesenchymal transition, and inhibit apoptosis. Targeting these progenitor stem cells may aid in improving the overall prognosis of the patient. These cancer stem cells are targeted using various markers that are apparently more or less specific to various types of stem cells.

Assessment of vitamin D levels in patients with oral potentially malignant disorders and oral squamous cell carcinoma-A cross-sectional study

Objectives

The aim of this study was to assess and compare the serum and salivary levels of Vitamin D in patients with oral potentially malignant disorders (OPMD) and Oral squamous cell carcinoma (OSCC) with healthy controls.

Method

This cross-sectional study was carried out among 60 patients reporting to the department of Oral Medicine and Radiology, and included patients with OPMDs, OSCC and healthy controls. The Vitamin D levels were estimated using the chemiluminescence immunoassay. One-way ANOVA was used to compare mean and statistical difference between the groups. Tukey's post HOC test calculated for inter group difference. Serum and salivary Vitamin D levels were corelated with Pearson's coefficient. The values of p < 0.005 was considered as significant.

Results

The levels of Vitamin D were decreased in study group as compared to controls both in serum and saliva. (p < 0.001). Between serum and salivary Vitamin D levels, a strong association was discovered using the Pearson's coefficient value of 0.737 (p < 0.001).

Conclusion

In this study, patients with both OPMDs and OSCC had Vitamin D insufficiency & deficiency. Vitamin D level assessment should be included as a standard component of routine investigations for these individuals.

Evaluation of Paxillin Expression in Epithelial Dysplasia, Oral Squamous Cell Carcinoma, Lichen Planus with and without Dysplasia, and Hyperkeratosis: A Retrospective Cross-Sectional Study

BACKGROUND

Paxillin is a cytoskeletal protein involved in the pathogenesis of several types of cancers. However, the roles of paxillin in epithelial dysplasia (ED), oral squamous cell carcinoma (OSCC), oral lichen planus with dysplasia (OLPD), hyperkeratosis (HK), and oral lichen planus (OLP) have remained unnoticed in the literature. This study aimed to evaluate its attainable functions in the pathogenesis and malignant transformation of potentially malignant oral epithelium and benign lesions.

METHODS

In this retrospective cross-sectional study, paxillin expression was investigated in 99 tissue samples, including 18 cases of OSCC, 21 ED, 23 OLP, 21 OLPD, and 16 cases of HK. The tissue sections also underwent immunohistochemical paxillin staining using 3,3-diaminobenzidine (DAB) chromogen. The intensity, location, and percentage of staining were examined across all groups. Data were analyzed using the Shapiro-Wilk test, ANOVA, Pearson chi-square, Kruskal-Wallis, and Dunn's post hoc test.

RESULTS

The cytoplasmic percentage and intensity staining of Paxillin expression were evident in the central/suprabasal and basal/peripheral layers of all the obtained samples. The final staining score was significantly higher in OSCC and dysplasia compared to HK and OLP (p = 0.004). It was found that paxillin expression is associated with the grade of dysplastic samples (p < 0.001).

CONCLUSION

The present study provides evidence that paxillin may be involved in the pathogenesis of OSCC and the development and progression of dysplastic tissue, since the paxillin expression was higher than that of HK and OLP.

IL-1RA promotes oral squamous cell carcinoma malignancy through mitochondrial metabolism-mediated EGFR/JNK/SOX2 pathway

BACKGROUND

Interleukin-1 receptor antagonist (IL-1RA), a member of the IL-1 family, has diverse roles in cancer development. However, the role of IL-1RA in oral squamous cell carcinoma (OSCC), in particular the underlying mechanisms, remains to be elucidated.

METHODS

Tumor tissues from OSCC patients were assessed for protein expression by immunohistochemistry. Patient survival was evaluated by Kaplan-Meier curve analysis. Impact of differential IL-1RA expression on cultured OSCC cell lines was assessed in vitro by clonogenic survival, tumorsphere formation, soft agar colony formation, and transwell cell migration and invasion assays. Oxygen consumption rate was measured by Seahorse analyzer or multi-mode plate reader. PCR array was applied to screen human cancer stem cell-related genes, proteome array for phosphorylation status of kinases, and Western blot for protein expression in cultured cells. In vivo tumor growth was investigated by orthotopic xenograft in mice, and protein expression in xenograft tumors assessed by immunohistochemistry.

RESULTS

Clinical analysis revealed that elevated IL-1RA expression in OSCC tumor tissues was associated with increased tumor size and cancer stage, and reduced survival in the patient group receiving adjuvant radiotherapy compared to the patient group without adjuvant radiotherapy. In vitro data supported these observations, showing that overexpression of IL-1RA increased OSCC cell growth, migration/invasion abilities, and resistance to ionizing radiation, whereas knockdown of IL-1RA had largely the opposite effects. Additionally, we identified that EGFR/JNK activation and SOX2 expression were modulated by differential IL-1RA expression downstream of mitochondrial metabolism, with application of mitochondrial complex inhibitors suppressing these pathways. Furthermore, in vivo data revealed that treatment with cisplatin or metformin-a mitochondrial complex inhibitor and conventional therapy for type 2 diabetes-reduced IL-1RA-associated xenograft tumor growth as well as EGFR/JNK activation and SOX2 expression. This inhibitory effect was further augmented by combination treatment with cisplatin and metformin.

CONCLUSIONS

The current study suggests that IL-1RA promoted OSCC malignancy through mitochondrial metabolism-mediated EGFR/JNK activation and SOX2 expression. Inhibition of this mitochondrial metabolic pathway may present a potential therapeutic strategy in OSCC.

The Promise of Nanoparticles-Based Radiotherapy in Cancer Treatment

Radiation has been utilized for a long time for the treatment of cancer patients. However, radiotherapy (RT) has many constraints, among which non-selectivity is the primary one. The implementation of nanoparticles (NPs) with RT not only localizes radiation in targeted tissue but also provides significant tumoricidal effect(s) compared to radiation alone. NPs can be functionalized with both biomolecules and therapeutic agents, and their combination significantly reduces the side effects of RT. NP-based RT destroys cancer cells through multiple mechanisms, including ROS generation, which in turn damages DNA and other cellular organelles, inhibiting of the DNA double-strand damage-repair system, obstructing of the cell cycle, regulating of the tumor microenvironment, and killing of cancer stem cells. Furthermore, such combined treatments overcome radioresistance and drug resistance to chemotherapy. Additionally, NP-based RT in combined treatments have shown synergistic therapeutic benefit(s) and enhanced the therapeutic window. Furthermore, a combination of phototherapy, i.e., photodynamic therapy and photothermal therapy with NP-based RT, not only reduces phototoxicity but also offers excellent therapeutic benefits. Moreover, using NPs with RT has shown promise in cancer treatment and shown excellent therapeutic outcomes in clinical trials. Therefore, extensive research in this field will pave the way toward improved RT in cancer treatment.

CD44 Mediates Oral Squamous Cell Carcinoma-Promoting Activity of MRE11 via AKT Signaling

Oral cancer is one of the highest-incidence malignancies worldwide, with the occurrence of oral squamous cell carcinoma (OSCC) being the most frequently diagnosed form. A barrier for oral cancer management may arise from tumor cells that possess properties of cancer stemness, which has been recognized as a crucial factor in tumor recurrence and metastasis. As such, understanding the molecular mechanisms underlying these tumor cells may provide insights for improving cancer treatment. MRE11 is the core protein of the RAD50/MRE11/NBS1 complex with a primary role in DNA damage repair, and it has been diversely associated with tumor development including OSCC. In this study, we aimed to investigate the engagement of CD44, a cancer stemness marker functioning in the control of cell growth and motility, in OSCC malignancy under the influence of MRE11. We found that overexpression of MRE11 enhanced CD44 expression and tumorsphere formation in OSCC cells, whereas knockdown of MRE11 reduced these phenomena. In addition, the MRE11-promoted tumorsphere formation or cell migration ability was compromised in OSCC cells carrying siRNA that targets CD44, as was the MRE11-promoted AKT phosphorylation. These were further supported by analyzing clinical samples, where higher CD44 expression was associated with lymph node metastasis. Additionally, a positive correlation between the expression of MRE11 and CD44, or that of CD44 and phosphorylated AKT, was observed in OSCC tumor tissues. Finally, the expression of CD44 was found to be higher in the metastatic lung nodules from mice receiving tail vein-injection with MRE11-overexpressing OSCC cells compared with control mice, and a positive correlation between CD44 and phosphorylated AKT was also observed in these metastatic lung nodules. Altogether, our current study revealed a previously unidentified mechanism linking CD44 and AKT in MRE11-promoted OSCC malignancy, which may shed light to the development of novel therapeutic strategies in consideration of this new pathway in OSCC.

Oct4 facilitates chondrogenic differentiation of mesenchymal stem cells by mediating CIP2A expression

Bone development and cartilage formation require strict modulation of gene expression for mesenchymal stem cells (MSCs) to progress through their differentiation stages. Octamer-binding transcription factor 4 (Oct4) expression is generally restricted to developing embryonic pluripotent cells, but its role in chondrogenic differentiation (CD) of MSCs remains unclear. We therefore investigated the role of Oct4 in CD using a microarray, quantitative real-time polymerase chain reaction, and western blotting. The expression of Oct4 was elevated when the CD of cultured MSCs was induced. Silencing Oct4 damaged MSC growth and proliferation and decreased CD, indicated by decreased cartilage matrix formation and the expression of Col2a1, Col10a1, Acan, and Sox9. We found a positive correlation between the expression of CIP2A, a natural inhibitor of protein phosphatase 2A (PP2A) and that of Oct4. Cellular inhibitor of PP2A (CIP2A) expression gradually increased after CD. Overexpression of CIP2A in MSCs with Oct4 depletion promoted cartilage matrix deposition as well as Col2a1, Col10a1, Acan, and Sox9 expression. The chondrogenic induction triggered c-Myc, Akt, ERK, and MEK phosphorylation and upregulated c-Myc and mTOR expression, which was downregulated upon Oct4 knockdown and restored by CIP2A overexpression. These findings indicated that Oct4 functions as an essential chondrogenesis regulator, partly via the CIP2A/PP2A pathway.

Ganoderma lucidum polysaccharides inhibit in vitro tumorigenesis, cancer stem cell properties and epithelial-mesenchymal transition in oral squamous cell carcinoma

ETHNOPHARMACOLOGICAL RELEVANCE

The polysaccharides of the millenary mushroom Ganoderma lucidum (GL) have been shown for decades to present anti-tumor activities, but few studies evaluated its importance on cancer stem cells and EMT process. Cancer stem cells (CSC) drive the development of carcinoma and are also involved in cancer treatment failure, being a good target for treatment success. Also, the process of epithelial-mesenchymal transition (EMT) is involved in metastasis and cancer relapse. Besides that, the increasing incidence worldwide of oral squamous cell carcinoma (OSCC) became a public health issue with a high rate of metastasis and poor quality of life for patients during and after treatment.

AIM OF THE STUDY

to evaluate G. lucidum polysaccharides (GLPS) in vitro effects on OSCC, focusing on hallmarks associated with tumorigenesis using the SCC-9, a squamous cells carcinoma lineage from the tongue.

MATERIALS AND METHODS

SCC-9 cells were treated in vitro for 72h with different GLPS concentrations. The controls cells were maintained with culture media only and cisplatin was used as treatment control. After the treatment period, the cells were evaluated.

RESULTS

GLPS treatment changed cell morphology and granularity, delayed migration, decreased colony, and impaired sphere formation, thereby leading to a non-invasive and less proliferative behavior of tumoral cells. Additionally, GLPS downregulated CSC, EMT, and drug sensitivity (ABC) markers.

CONCLUSIONS

These results show that the natural product GLPS has the potential to be an important ally for tongue squamous cell carcinoma treatment, bringing the millenary compound to modern therapy, providing a basis for future studies and the improvement of life quality for OSCC patients.

Oral Cancer Stem Cells: Therapeutic Implications and Challenges

Head and neck squamous cell carcinoma (HNSCC) is currently one of the 10 most common malignancies worldwide, characterized by a biologically highly diverse group of tumors with non-specific biomarkers and poor prognosis. The incidence rate of HNSCC varies widely throughout the world, with an evident prevalence in developing countries such as those in Southeast Asia and Southern Africa. Tumor relapse and metastasis following traditional treatment remain major clinical problems in oral cancer management. Current evidence suggests that therapeutic resistance and metastasis of cancer are mainly driven by a unique subpopulation of tumor cells, termed cancer stem cells (CSCs), or cancer-initiating cells (CICs), which are characterized by their capacity for self-renewal, maintenance of stemness and increased tumorigenicity. Thus, more understanding of the molecular mechanisms of CSCs and their behavior may help in developing effective therapeutic interventions that inhibit tumor growth and progression. This review provides an overview of the main signaling cascades in CSCs that drive tumor repropagation and metastasis in oral cancer, with a focus on squamous cell carcinoma. Other oral non-SCC tumors, including melanoma and malignant salivary gland tumors, will also be considered. In addition, this review discusses some of the CSC-targeted therapeutic strategies that have been employed to combat disease progression, and the challenges of targeting CSCs, with the aim of improving the clinical outcomes for patients with oral malignancies. Targeting of CSCs in head and neck cancer (HNC) represents a promising approach to improve disease outcome. Some CSC-targeted therapies have already been proven to be successful in pre-clinical studies and they are now being tested in clinical trials, mainly in combination with conventional treatment regimens. However, some studies revealed that CSCs may not be the only players that control disease relapse and progression of HNC. Further, clinical research studying a combination of therapies targeted against head and neck CSCs may provide significant advances.

SUZ12 participates in the proliferation of PNH clones by regulating histone H3K27me3 levels

Paroxysmal nocturnal hemoglobinuria (PNH) is a disease involving hematopoietic stem cell membrane defects caused by acquired phosphatidylinositol glycan anchor biosynthesis class A (PIGA) mutations. In this study, 97 target genes were selected as a target gene panel and screened in 23 PNH patients via the sequencing of specific DNA target regions. Through functional analysis, we identified that suppressor-of-Zeste 12 (SUZ12) may be involved in the proliferation of PNH clones. mRNA and protein expression levels of SUZ12 and the trimethylation level of histone H3 at lysine 27 (H3K27) in CD59^- peripheral blood leukocytes from PNH patients were higher than those in CD59⁺ cells from PNH patients and peripheral blood leukocytes from healthy controls. In addition, the relative expression of SUZ12 in PNH patients was positively correlated with Ret% and the proportion of PNH clones. When we knocked down SUZ12 expression in a PIGA knockdown THP-1 cell line (THP-1 KD cells), the trimethylation of histone H3K27(H3K27me3) and cell proliferation decreased, apoptosis increased, and cell cycle arrest occurred in G0/G1 phase. In conclusion, SUZ12 participates in the proliferation of PNH clones by regulating histone H3K27me3 levels. Our results may provide new therapeutic targets and possibilities for PNH patients.

Targeting Cancer Stem Cell Markers or Pathways: A Potential Therapeutic Strategy for Oral Cancer Treatment

Cancer stem cells (CSCs) are a small subset of cancer cells with stem cell-like properties, self-renewal potential, and differentiation capacity into multiple cell types. Critical genetic alterations or aberrantly activated signaling pathways associated with drug resistance and recurrence have been observed in multiple types of CSCs. In this context, CSCs are considered to be responsible for tumor initiation, growth, progression, therapeutic resistance, and metastasis. Therefore, to effectively eradicate CSCs, tremendous efforts have been devoted to identify specific target molecules that play a critical role in regulating their distinct functions and to develop novel therapeutics, such as proteins, monoclonal antibodies, selective small molecule inhibitors, and small antisense RNA (asRNA) drugs. Similar to other CSC types, oral CSCs can be characterized by certain pluripotency-associated markers, and oral CSCs can also survive and form 3D tumor spheres in suspension culture conditions. These oral CSC-targeting therapeutics selectively suppress specific surface markers or key signaling components and subsequently inhibit the stem-like properties of oral CSCs. A large number of new therapeutic candidates have been tested, and some products are currently in the pre-clinical or clinical development phase. In the present study, we review new oral CSC-targeted therapeutic strategies and discuss the various specific CSC surface markers and key signaling components involved in the stem-like properties, growth, drug resistance, and tumorigenicity of oral CSCs.

SOD2 Enhancement by Long-Term Inhibition of the PI3K Pathway Confers Multi-Drug Resistance and Enhanced Tumor-Initiating Features in Head and Neck Cancer

The phosphoinositide-3-kinase (PI3K) pathway has widely been considered as a potential therapeutic target for head and neck cancer (HNC); however, the application of PI3K inhibitors is often overshadowed by the induction of drug resistance with unknown mechanisms. In this study, PII3K inhibitor resistant cancer cells were developed by prolonged culturing of cell lines with BEZ235, a dual PI3K and mammalian target of rapamycin (mTOR) inhibitor. The drug resistant HNC cells showed higher IC₅₀ of the proliferation to inhibitors specifically targeting PI3K and/or mTOR, as compared to their parental cells. These cells also showed profound resistance to drugs of other classes. Molecular analysis revealed persistent activation of phosphorylated AKT at threonine 308 in the drug resistant cells and increased expression of markers for tumor-initiating cells. Interestingly, increased intra-cellular ROS levels were observed in the drug resistant cells. Among anti-oxidant molecules, the expression of SOD2 was increased and was associated with the ALDH-positive tumor-initiating cell features. Co-incubation of SOD inhibitors and BEZ235 decreased the stemness feature of the cells in vitro, as shown by results of the spheroid formation assay. In conclusion, dysregulation of SOD2 might contribute to the profound resistance to PI3K inhibitors and the other drugs in HNC cells.

Metronomic Therapy in Oral Squamous Cell Carcinoma

Metronomic therapy is characterized by drug administration in a low-dose, repeated, and regular manner without prolonged drug-free interval. The two main anticancer mechanisms of metronomic therapy are antiangiogenesis and immunomodulation, which have been demonstrated in several delicate in vitro and in vivo experiments. In contrast to the traditional maximum tolerated dose (MTD) dosing of chemotherapy, metronomic therapy possesses comparative efficacy but greatlydecreases the incidence and severity of treatment side-effects. Clinical trials of metronomic anticancer treatment have revealed promising results in a variety cancer types and specific patient populations such as the elderly and pediatric malignancies. Oral cavity squamous cell carcinoma (OCSCC) is an important health issue in many areas around the world. Long-term survival is about 50% in locally advanced disease despite having high-intensity treatment combined surgery, radiotherapy, and chemotherapy. In this article, we review and summarize the essence of metronomic therapy and focus on its applications in OCSCC treatment.

Clinicopathological correlation of stem cell markers expression in oral squamous cell carcinoma; relation to patients` outcome

Background: Squamous cell carcinoma (OSCC) is the commonest oral malignancy.The overall 5 year survival of OSCC has remained at 50%, largely unchanged for 40 years. CSCs are important within the development, invasion, drug resistance, and prediction of carcinomas treatment outcome. ALDH1 and CD44 are commonly used epithelial tumors cancer stem-like cells surface markers. Materials: Our study aimed to judge CD44 and ALDH1 immunohistochemical expressions in 44 cases of OSCC and relates the expression to patients' survival. Results: High CD44 & ALDH1 expressions were significantly expressed in variable histologic grades of OSCCs, large sized carcinomas, presence lymph vascular invasion, presence of nodal and distant metastasis, advanced TNM clinical stage, recurrence and death during follow up period (P ≤ 0.05). Reduced DFS and three years overall survival were significantly recorded in cases with high CD44 expression, and high ALDH1 expression (p < 0.05). CD44 & ALDH1 expressions, histologic grade, tumor size were the independent predictors of DFS and three years OS. Conclusion: CD44 and ALDH1 expressions are valuable prognostic factors in OSCC and could be well considered predictors for patients' 3 years OS and DFS.

Oral cancer management in the SARS-CoV-2 Pandemic-Indian scenario

The global burden of oral cancer rests on India's shoulders. Distant metastasis and extensive loco-regional spread result in a dismal 5-year prognosis. Tobacco chewing is the leading etiological factor. A lack of education among the masses combined with an inundated cancer care system account for high morbidity and mortality rates. The SARS-CoV-2 shows tropism for the oral mucosa. This viral tropism is thought to get augmented in oral cancer because of the upregulation of oral mucosal receptors and enzymes which enhance viral attachment and entry. The COVID-19 disease has caused a heavy blow to the cancer care sector in India because of paucity of COVID-19 centred health care regulations. This review highlights the need for the prompt creation of a national health policy which would prioritize and allow for the resumption of oral onco-surgical in light of COVID-19 pandemic.

Enteromorpha compressa extract induces anticancer activity through apoptosis and autophagy in oral cancer

Marine algae are an auspicious source of innovative bioactive compounds containing possible therapeutic agents against mammalian cancers. However, the mechanism by which bioactive algal compounds exhibit anticancer activity against oral squamous cell carcinoma (OSCC) is scant. The main objective of the current study was to explore the properties of the Enteromorpha compressa solvent extracts that induced autophagy and apoptosis with reference to their potent phytochemical and antioxidant properties. The presence of bioactive compounds were confirmed by UV and FT-IR spectroscopy. The free radical scavenging activity were analyzed by evaluating H₂O₂, DPPH, superoxide and hydroxyl activity. The anticancer activities of the extracts were investigated by employing clonogenic and scratch assay. The apoptosis potential was evaluated by DAPI and MMP by Rh123 fluorescence assay. Moreover, the CAT, SOD, GPX, APX, and GR activities were measured. The autophagy potential was evaluated by LC3 puncta formation, acridine orange in addition to LysoTracker staining. The present investigation revealed that the methanolic extract of E. compressa elicited robust free radical scavenging activity that discerns its antiproliferative potency. Moreover, the methanolic algal extract boosted intrinsic apoptosis against OSCC by downregulating protective antioxidant enzymes. Furthermore, it also revealed induction of autophagy to promote cell death in oral cancer cells. The presence of novel bioactive compounds in E. compressa has uncovered possible therapeutic value against OSCC by modulating antioxidant defense system, apoptosis and autophagy that could be used to explore very competent algal candidates for the development of potential alternative anticancer drugs.

Mitochondrial rewiring through mitophagy and mitochondrial biogenesis in cancer stem cells: A potential target for anti-CSC cancer therapy

Cancer stem cells (CSCs) are distinct subpopulations of cancer cells with stem cell-like abilities and are more resilient to chemotherapy, causing tumor relapse. Mitophagy, a selective form of autophagy, removes damaged unwanted mitochondria from cells through a lysosome-based degradation pathway to maintain cellular homeostasis. CSCs use mitophagy as a chief survival response mechanism for their growth, propagation, and tumorigenic ability. Mitochondrial biogenesis is a crucial cellular event replacing damaged mitochondria through the coordinated regulation of several transcription factors to achieve the bioenergetic demands of the cell. Because of the high mitochondrial content in CSCs, mitochondrial biogenesis is an interesting target to address the resistance mechanisms of anti-CSC therapy. However, to what extent both mitophagy and mitochondrial biogenesis are vital in promoting stemness, metabolic reprogramming, and drug resistance in CSCs has yet to be established. Therefore, in this review, we focus on understanding the interesting aspects of mitochondrial rewiring that involve mitophagy and mitochondrial biogenesis in CSCs. We also discuss their coordinated regulation in the elimination of CSCs, with respect to stemness and differentiation of the CSC phenotype, and the different aspects of tumorigenesis such as cancer initiation, progression, resistance, and tumor relapse. Finally, we address several other unanswered questions relating to targeted anti-CSC cancer therapy, which improves patient survival.

Loss of oral mucosal stem cell markers in oral submucous fibrosis and their reactivation in malignant transformation

The integrity of the basal stem cell layer is critical for epithelial homoeostasis. In this paper, we review the expression of oral mucosal stem cell markers (OM-SCMs) in oral submucous fibrosis (OSF), oral potentially malignant disorders (OPMDs) and oral squamous cell carcinoma (OSCC) to understand the role of basal cells in potentiating cancer stem cell behaviour in OSF. While the loss of basal cell clonogenicity triggers epithelial atrophy in OSF, the transition of the epithelium from atrophic to hyperplastic and eventually neoplastic involves the reactivation of basal stemness. The vacillating expression patterns of OM-SCMs confirm the role of keratins 5, 14, 19, CD44, β1-integrin, p63, sex-determining region Y box (SOX2), octamer-binding transcription factor 4 (Oct-4), c-MYC, B-cell-specific Moloney murine leukaemia virus integration site 1 (Bmi-1) and aldehyde dehydrogenase 1 (ALDH1) in OSF, OPMDs and OSCC. The downregulation of OM-SCMs in the atrophic epithelium of OSF and their upregulation during malignant transformation are illustrated with relevant literature in this review.

Serum levels of 25-hydroxy-vitamin D in patients with oral squamous cell carcinoma: Making a case for chemoprevention

Objectives

Serum level of vitamin D has been used as a predictor for cancer development. We intend to measure the baseline vitamin D level in patients with oral squamous cell carcinoma (OSCC) and to compare same with non‐cancer controls to determine any association.

Materials and methods

Patients with OSCC presenting to our clinics were included in this study. Their baseline serum vitamin D levels were measured prior to cancer treatment after obtaining their consents. These patients were then matched with at least 2 cancer‐free subjects to serve as controls and whose serum vitamin D levels were also measured. The serum vitamin D levels obtained for the two groups were then categorized into normal (>35 ng/ml), mild deficiency (25–35 ng/ml), moderate deficiency (12.5–25 ng/ml), and severe deficiency (<12.5 ng/ml). The data were analyzed statistically and the two groups compared.

Results

A total of 51 patients with OSCC (Male 22 [43%] and female 29 [57%]) and 113 cancer‐free controls (Male 36 [31.86%] and female 77 [68.14%]) were included in the study. The commonest site for OSCC was the tongue, accounting for 45% of the cancer cases. Mean age for cancer patients was 59.33 years ±12.54 and 49.24 years ±15.79 for the control. Among the OSCC patients, 74.51% had moderate to severe vitamin D deficiencies, whereas only 20.35% had a moderate deficiency in the control group with no severe deficiency.

Conclusion

Logistic regression analysis shows a positive association between vitamin D deficiency and OSCC risk especially in levels below 25 ng/ml. This further corroborates the assertion that vitamin D deficiency may be a useful indicator of OSCC. It may, therefore, be necessary to routinely prescribe vitamin D supplements to subjects with moderate to severe deficiencies in order to decrease the chances of OSCC development.

SOX2 Expression Is an Independent Predictor of Oral Cancer Progression

Potentially malignant oral lesions, mainly leukoplakia, are common. Malignant transformation varies widely, even in the absence of histological features such as dysplasia. Hence, there is a need for novel biomarker-based systems to more accurately predict the risk of cancer progression. The pluripotency transcription factor SOX2 is frequently overexpressed in cancers, including oral squamous cell carcinoma (OSCC), thereby providing a link between malignancy and stemness. This study investigates the clinical relevance of SOX2 protein expression in early stages of oral carcinogenesis as a cancer risk biomarker, and also its impact on prognosis and disease outcome at late stages of OSCC progression. SOX2 expression was evaluated by immunohistochemistry in 55 patients with oral epithelial dysplasia, and in 125 patients with OSCC, and correlated with clinicopathological data and outcomes. Nuclear SOX2 expression was detected in four (7%) cases of oral epithelial dysplasia, using a cut-off of 10% stained nuclei, and in 16 (29%) cases when any positive nuclei was evaluated. Univariate analysis showed that SOX2 expression and histopathological grading were significantly associated with oral cancer risk; and both were found to be significant independent predictors in the multivariate analysis. Nuclear SOX2 expression was also found in 49 (39%) OSCC cases, was more frequent in early tumor stages and N0 cases, and was associated with a better survival. In conclusion, SOX2 expression emerges as an independent predictor of oral cancer risk in patients with oral leukoplakia. These findings underscore the relevant role of SOX2 in early oral tumorigenesis rather than in tumor progression.

Targeting cancer stem cells in squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive tumor and the sixth most common cancer worldwide. Current treatment strategies for HNSCC are surgery, radiotherapy, chemotherapy, immunotherapy or combinatorial therapies. However, the overall 5-year survival rate of HNSCC patients remains at about 50%. Cancer stem cells (CSCs), a small population among tumor cells, are able to self-renew and differentiate into different tumor cell types in a hierarchical manner, similar to normal tissue. In HNSCC, CSCs are proposed to be responsible for tumor initiation, progression, metastasis, drug resistance, and recurrence. In this review, we discuss the molecular and cellular characteristics of CSCs in HNSCC. We summarize current approaches used in the literature for identification of HNSCC CSCs, and mechanisms required for CSC regulation. We also highlight the role of CSCs in treatment failure and therapeutic targeting options for eliminating CSCs in HNSCC.

Pantoprazole pretreatment elevates sensitivity to vincristine in drug-resistant oral epidermoid carcinoma in vitro and in vivo

Resistance to chemotherapeutic agents is a major cause of treatment failure in patients with oral cancer. Proton pump inhibitors (PPIs), essentially H⁺-K⁺-ATPase inhibitors which are currently used in the treatment of acid related diseases, have demonstrated promising antitumor and chemo-sensitizing efficacy. The main purpose of the present study was to investigate whether pantoprazole (PPZ, one of PPIs) could increase the sensitivity of chemoresistant oral epidermoid carcinoma cells (KB/V) to vincristine (VCR) and elucidate the underlying action mechanism. Results showed that combination treatment of PPZ and VCR synergistically inhibited the proliferation of KB/V cells in vitro and in vivo. Furthermore, administration of PPZ and VCR not only induce apoptosis and G2/M phase arrest in KB/V cells but also suppress the migration and invasion of KB/V cells. The mechanism underlying synergistic anti-tumor effect of PPZ and VCR was related to the inhibition of the function and expression of P-glycoprotein (P-gp) and the down-regulation of EGFR/MAPK and PI3K/Akt/mTOR signaling pathways in KB/V cells. Additionally, we observed that PPZ treatment induced an increase in lysosomal pH and inhibited the activity of lysosomal enzyme acid phosphatase in KB/V cells, which could functionally reduce the sequestration of VCR in lysosomes and sensitized KB/V cells to VCR. In conclusion, our study demonstrated that PPZ could be included in new combined therapy of human oral cancer (especially on VCR-resistant therapy) together with VCR.

The Emerging Role of NANOG as an Early Cancer Risk Biomarker in Patients with Oral Potentially Malignant Disorders

NANOG, a key regulator of pluripotency and self-renewal in embryonic and adult stem cells, is frequently overexpressed in multiple cancers, including oral squamous cell carcinoma (OSCC). It has been frequently associated with poor outcomes in epithelial cancers, and recently implicated in laryngeal tumorigenesis. On this basis, we investigated the role of NANOG protein expression as an early cancer risk biomarker in oral potentially malignant disorders (OPMD), and the impact on prognosis and disease outcomes in OSCC patients. NANOG expression was evaluated by immunohistochemistry in 55 patients with oral epithelial dysplasia, and 125 OSCC patients. Correlations with clinical and follow-up data were assessed. Nuclear NANOG expression was detected in 2 (3.6%) and cytoplasmic NANOG expression in 9 (16.4%) oral dysplasias. NANOG expression increased with the grade of dysplasia. Cytoplasmic NANOG expression and the histopathological grading were significantly correlated with oral cancer risk, although dysplasia grading was the only significant independent predictor of oral cancer development in multivariate analyses. Cytoplasmic NANOG expression was also detected in 39 (31%) OSCC samples. Positive NANOG expression was significantly associated with tobacco and alcohol consumption, and was more frequent in pN0 tumors, early I-II stages. These data unveil the clinical relevance of NANOG in early stages of OSCC tumorigenesis rather than in advanced neoplastic disease. NANOG expression emerges as an early predictor of oral cancer risk in patients with OPMD.

p73 induction by Abrus agglutinin facilitates Snail ubiquitination to inhibit epithelial to mesenchymal transition in oral cancer

BACKGROUND

Epithelial-to-mesenchymal transition (EMT), a key step in oral cancer progression, is associated with invasion, metastasis, and therapy resistance, thus targeting the EMT represents a critical therapeutic strategy for the treatment of oral cancer metastasis. Our previous study showed that Abrus agglutinin (AGG), a plant lectin, induces both intrinsic and extrinsic apoptosis to activate the tumor inhibitory mechanism.

OBJECTIVE

This study aimed to investigate the role of AGG in modulating invasiveness and stemness through EMT inhibition for the development of antineoplastic agents against oral cancer.

METHODS

The EMT- and stemness-related proteins were studied in oral cancer cells using Western blot analysis and fluorescence microscopy. The potential mechanisms of Snail downregulation through p73 activation in FaDu cells were evaluated using Western blot analysis, immunoprecipitation, confocal microscopy, and molecular docking analysis. Immunohistochemical staining of the tumor samples of AGG-treated FaDu-xenografted nude mice was performed.

RESULTS

At the molecular level, AGG-induced p73 suppressed Snail expression, leading to EMT inhibition in FaDu cells. Notably, AGG promoted the translocation of Snail from the nucleus to the cytoplasm in FaDu cells and triggered its degradation through ubiquitination. In this setting, AGG inhibited the interaction between Snail and p73 in FaDu cells, resulting in p73 activation and EMT inhibition. Moreover, in epidermal growth factor (EGF)-stimulated FaDu cells, AGG abolished the upregulation of extracellular signal-regulated kinase (ERK)1/2 that plays a pivotal role in the upregulation of Snail to regulate the EMT phenotypes. In immunohistochemistry analysis, FaDu xenografts from AGG-treated mice showed decreased expression of Snail, SOX2, and vimentin and increased expression of p73 and E-cadherin compared with the control group, confirming EMT inhibition as part of its anticancer efficacy against oral cancer.

CONCLUSION

In summary, AGG stimulates p73 in restricting EGF-induced EMT, invasiveness, and stemness by inhibiting the ERK/Snail pathway to facilitate the development of alternative therapeutics for oral cancer.

LATS1/2 kinases trigger self-renewal of cancer stem cells in aggressive oral cancer

Cancer stem cells (CSCs), which play important roles in tumor initiation and progression, are resistant to many types of therapies. However, the regulatory mechanisms underlying CSC-specific properties, including self-renewal, are poorly understood. Here, we found that LATS1/2, the core Hippo pathway-kinases, were highly expressed in the oral squamous cell carcinoma line SAS, which exhibits high capacity of CSCs, and that depletion of these kinases prevented SAS cells from forming spheres under serum-free conditions. Detailed examination of the expression and activation of LATS kinases and related proteins over a time course of sphere formation revealed that LATS1/2 were more highly expressed and markedly activated before initiation of self-renewal. Moreover, TAZ, SNAIL, CHK1/2, and Aurora-A were expressed in hierarchical, oscillating patterns during sphere formation, suggesting that the process consists of four sequential steps. Our results indicate that LATS1/2 trigger self-renewal of CSCs by regulating the Hippo pathway, the EMT, and cell division.

Role of vitamin D and vitamin D receptor (VDR) in oral cancer

Oral cancer is known as one of the most common cancers, with a poor prognosis, related to delayed clinical diagnosis, either due to the lack of particular biomarkers related to the disease or costly therapeutic alternatives. Vitamin D executes its functions by interacting with the vitamin D receptor (VDR), both in healthy and diseased individuals, including oral cancer. This review discusses the role of vitamin D and VDR on tumorigenesis, emphasizing on oral cancer. Furthermore, regulation of VDR expression, mechanisms of anticancer effects of calcitriol, oral cancer chemoresistance and its relation with VDR and polymorphisms of VDR gene will be discussed. The manuscript is prepared mainly using the information collected from PubMed and MEDLINE.

MicroRNA‑495 targets Notch1 to prohibit cell proliferation and invasion in oral squamous cell carcinoma

MicroRNAs (miRNAs) are associated with the initiation and progression of oral squamous cell carcinoma (OSCC) by regulating a variety of cancer‑associated behaviors. Fully understanding the regulatory mechanism of miRNAs in the pathogenesis of OSCC may provide novel promising approaches for the identification of prognostic biomarkers and therapeutic targets for this particular malignancy. In the present study, reverse transcription‑quantitative polymerase chain reaction analysis was performed to detect miRNA (miR)‑495 expression in OSCC tissues and cell lines. The effects of miR‑495 on the proliferation and invasion of OSCC cells were determined using Cell Counting Kit‑8 and Matrigel invasion assays, respectively. The mechanisms underlying the action of miR‑495 in OSCC cells were also investigated. Results from the present study revealed that miR‑495 expression was downregulated in OSCC tissues and cell lines compare with in adjacent normal tissues and human oral keratinocytes, respectively. Exogenous expression of miR‑495 restricted cell proliferation and invasion of OSCC cells in vitro. Notch1 was identified as a direct functional target of miR‑495 in OSCC. Furthermore, Notch1 knockdown exhibited inhibitory effects, similar to those induced by miR‑495 overexpression in OSCC cells. Restoration of Notch1 expression rescued the suppressive effects of miR‑495 on OSCC cell proliferation and invasion. These findings suggested an important role for miR‑495 in the regulation of OSCC cell growth and metastasis, at least partly by directly targeting Notch1. In addition, the findings of the present study revealed the potential of miR‑495 as a novel therapeutic target for the treatment of patients with OSCC.

Anaplastic transition within the cancer microenvironment in early-stage oral tongue squamous cell carcinoma is associated with local recurrence

The cancer microenvironment (CME) promotes malignant progression of cancer cells by stimulating cell growth, migration and invasion. Cancer-associated fibroblasts (CAFs), prominent features of the CME, interact directly with cancer cells and facilitate epithelial-mesenchymal transition (EMT). The present study examined the spatial distribution of CAFs and EMT on cancer cells in patients with early-stage tongue squamous cell carcinoma (TSCC) and their association with local recurrence. The present study included 14 patients with early-stage TSCC who had undergone glossectomy between 2006 and 2015, of which 7 experienced local recurrence (LR group) and 7 did not (control group). Multiple immunofluorescent analysis (MIA) of PCNA, αSMA, vimentin, E-cadherin and cytokeratin 14 (CK14) was performed on slides obtained from surgical specimens to identify the expression of various cell-specific markers. The number of CAFs in the CME was significantly increased in the LR group (P=0.001). Furthermore, the neighbouring cancer cells were positive for vimentin expression, indicating EMT. However, the present study also identified concurrent expression of CK14 in all vimentin-positive cancer cells, whilst epithelial markers, including E-cadherin, were expressed in certain vimentin-positive cancer cells. Concurrent expression of CK14 and vimentin is not defined as EMT or partial EMT. Therefore, the present study proposed a novel mechanism of anaplastic transition (APT), in which epithelial cancer cells concurrently develop mesenchymal features, which is achieved by pathways other than EMT. APT is characterized such that epithelial cancer cells differentiate into more primitive states, which is different from EMT or partial EMT, and it may be associated with LR. The concept aids in improving knowledge regarding tumor recurrence in patients with early-stage TSCC.

Anti-Apoptotic Mechanisms of Acupuncture in Neurological Diseases: A Review

Apoptosis, known as programmed cell death, plays a significant role in the pathogenesis of neurological diseases. Most of these diseases can be obviously alleviated by means of acupuncture treatment. Current research studies have shown that the efficacy of acupuncture to these medical conditions is closely associated with the anti-apoptotic potentials. Mainly based on the acupuncture's anti-apoptotic efficacy in prevalent neurological disorders, including cerebral ischemia-reperfusion injury, Alzheimer's disease, depression or stress related-modes, spinal cord injuries, etc., this review comes to a conclusion that the anti-apoptotic effect of acupuncture treatment for neurological diseases, evidently reflected through Bcl-2, Bax or caspase expression change, results from regulating mitochondrial or autophagic dysfunction as well as reducing oxidative stress and inflammation. The possible mechanisms of acupuncture's anti-apoptotic effect are associated with a series of downstream signaling pathways and the up-regulated expression of neurotrophic factors. It is of great importance to illuminate the exact mechanisms of acupuncture treatment for neurological dysfunctions.

Cellular Plasticity-Targeted Therapy in Head and Neck Cancers

Head and neck cancer is one of the most frequent human malignancies worldwide, with a high rate of recurrence and metastasis. Head and neck squamous cell carcinoma (HNSCC) is cellularly and molecularly heterogeneous, with subsets of undifferentiated cancer cells exhibiting stem cell-like properties, called cancer stem cells (CSCs). Epithelial-mesenchymal transition, gene mutation, and epigenetic modification are associated with the formation of cellular plasticity of tumor cells in HNSCC, contributing to the acquisition of invasive, recurrent, and metastatic properties and therapeutic resistance. Tumor microenvironment (TME) plays a supportive role in the initiation, progression, and metastasis of head and neck cancer. Stromal fibroblasts, vasculature, immune cells, cytokines, and hypoxia constitute the main components of TME in HNSCC, which contributes not only to the acquisition of CSC properties but also to the recurrence and therapeutic resistance of the malignancies. In this review, we discuss the potential mechanisms underlying the development of cellular plasticity, especially the emergence of CSCs, in HNSCC. We also highlight recent studies implicating the complex interplays among TME components, plastic CSCs, tumorigenesis, recurrence, and therapeutic resistance of HNSCC. Finally, we summarize the treatment modalities of HNSCC and reinforce the novel concept of therapeutic targeting CSCs in HNSCC.

EGF induces epithelial-mesenchymal transition and cancer stem-like cell properties in human oral cancer cells via promoting Warburg effect

"Warburg effect", the enhanced glycolysis or aerobic glycolysis, confers cancer cells the ability to survive and proliferate even under stressed conditions. In this study, we explored the role of epidermal growth factor (EGF) in orchestrating Warburg effect, the epithelial-mesenchymal transition (EMT) process, and the acquisition of cancer stem-like cell properties in human oral squamous cell carcinoma (OSCC) cells. Our results showed that EGF induces EMT process in OSCC cells, which correlates with the acquisition of cancer stem-like properties, including the enrichment of CD44+/CD24- population of cancer cells and an increased expression of CSC-related genes, aldehyde dehydrogenase-1 (ALDH1) and Bmi-1. We also showed that EGF concomitantly enhanced L-lactate production, while blocking glycolysis by 2-deoxy-D-glucose (2-DG) robustly reversed EGF-induced EMT process and CSC-like properties in OSCC cells. Mechanistically, we demonstrated that EGF promoted EMT process and CSC generation through EGFR/PI3K/HIF-1α axis-orchestrated glycolysis. Using an orthotopic tumor model of human OSCC (UM-SCC1) injected in the tongue of BALB/c nude mice, we showed that treatment with 2-DG in vivo significantly inhibited the metastasis of tumor cells to the regional cervical lymph nodes and reduced the expression of ALDH1 and vimentin in both in situ tumors and tumor cell-invaded regional lymph nodes. Taken together, these findings have unveiled a new mechanism that EGF drives OSCC metastasis through induction of EMT process and CSC generation, which is driven by an enhanced glycolytic metabolic program in OSCC cells.

Identification and Characterization of Stem Cells in Oral Cancer

Cancer stem cells (CSCs) are a subpopulation of cells within a heterogeneous tumor that have enhanced biologic properties such as increased capacity for self-renewal, increased tumorigenicity, enhanced differentiation capacity, and resistance to chemo- and radiotherapies. This unit describes protocols to isolate and characterize potential cancer stem cells from a solid tumor (oral cancer). This involves creating a single-cell suspension from tumor tissue, tagging the cell subpopulation of interest, and sorting cells into different populations. Finally, the sorted subpopulations can be evaluated for their ability to meet the functional requirements of a CSC, which primarily include increased tumorigenicity in an in vivo xenograft assay. Mastering the protocols in this unit will allow the researcher to study populations of cells that may have properties of CSCs.

Autophagy regulates cisplatin-induced stemness and chemoresistance via the upregulation of CD44, ABCB1 and ADAM17 in oral squamous cell carcinoma

OBJECTIVE

We inspected the relevance of CD44, ABCB1 and ADAM17 in OSCC stemness and deciphered the role of autophagy/mitophagy in regulating stemness and chemoresistance.

MATERIAL AND METHODS

A retrospective analysis of CD44, ABCB1 and ADAM17 with respect to the various clinico-pathological factors and their correlation was analysed in sixty OSCC samples. Furthermore, the stemness and chemoresistance were studied in resistant oral cancer cells using sphere formation assay, flow cytometry and florescence microscopy. The role of autophagy/mitophagy was investigated by transient transfection of siATG14, GFP-LC3, tF-LC3, mKeima-Red-Mito7 and Western blot analysis of autophagic and mitochondrial proteins.

RESULTS

In OSCC, high CD44, ABCB1 and ADAM17 expressions were correlated with higher tumour grades and poor differentiation and show significant correlation in their co-expression. In vitro and OSCC tissue double labelling confirmed that CD44⁺ cells co-expresses ABCB1 and ADAM17. Further, cisplatin (CDDP)-resistant FaDu cells displayed stem-like features and higher CD44, ABCB1 and ADAM17 expression. Higher autophagic flux and mitophagy were observed in resistant FaDu cells as compared to parental cells, and inhibition of autophagy led to the decrease in stemness, restoration of mitochondrial proteins and reduced expression of CD44, ABCB1 and ADAM17.

CONCLUSION

The CD44⁺ /ABCB1⁺ /ADAM17⁺ expression in OSCC is associated with stemness and chemoresistance. Further, this study highlights the involvement of mitophagy in chemoresistance and autophagic regulation of stemness in OSCC.

MiR-139-5p inhibits the tumorigenesis and progression of oral squamous carcinoma cells by targeting HOXA9

Our study sought to clarify the effects of microRNA-139-5p (miR-139-5p) in the tumorigenesis and progression of oral squamous cell carcinoma (OSCC) by regulating HOXA9. MiR-139-5p and HOXA9 expression in OSCC tissues, tumour adjacent tissues, OSCC cells and normal cells were tested by qRT-PCR. SAS and CAL-27 cell lines were selected in among four OSCC cell lines and then transfected with miR-139-5p mimics, pEGFP-HOXA9 and cotransfected with miR-139-5p mimics + pEGFP-HOXA9. We used MTT, colony formation, transwell and wound healing assays to analyse cell viability, proliferation, invasion and migration. The target relationship between miR-139-5p and HOXA9 was verified by luciferase reporter assay and Western blot, respectively. MiR-139-5p was down-regulated, whereas HOXA9 was up-regulated in OSCC tissues and cells. The proliferation, invasion and migration ability of SAS and CAL-27 cells in miR-139-5p mimics group were significantly weaker than those in the control group and the miR-NC group (P < 0.01). MiR-139-5p can negatively regulate HOXA9. The proliferation, invasion and migration of SAS and CAL-27 cells in the miR-139-5p mimics + pEGFP-HOXA9 group were not significantly different from those in the blank control and negative control groups (P > 0.05). Our results indicated that miR-139-5p could directly inhibit HOXA9, which might be a potential mechanism in inhibiting the proliferation, invasiveness and migration of OSCC cells.

Expression of vitamin D receptor and vitamin D status in patients with oral neoplasms and effect of vitamin D supplementation on quality of life in advanced cancer treatment

AIM OF THE STUDY

Vitamin D receptor (VDR) expression and serum vitamin D scores in oral premalignant lesions and oral cancer have not been widely analyzed. The role of vitamin D supplementation in advanced oral cancer for improving quality of life (QOL) is also a matter of research.

MATERIAL AND METHODS

Vitamin D receptor expression and vitamin D scores were analyzed in normal oral mucosa (n = 95), leukoplakia (n = 23) and oral cancer (n = 87). 45 patients with advanced oral cancer subjected to chemoradiation were evaluated for the effect of vitamin D supplementation on most observable QOL parameters such as oral mucositis, swallowing performance and overall QOL.

RESULTS

Vitamin D receptor expression was increased in oral neoplastic lesions. Vitamin D scores were significantly lower in cases compared to healthy controls (p = 0.002). Vitamin D supplementation significantly reduced the therapy-related toxicities in advanced cancer, thus reducing morbidity and improving QOL.

CONCLUSIONS

Vitamin D receptor expression is increased in premalignant lesions and oral cancer. Vitamin D insufficiency and deficiency are prevalent in patients with oral neoplastic lesions. Vitamin D supplementation has a role in reducing treatment-related toxicities, especially in advanced cancer.

Cancer Stem Cells in Oral Cavity Squamous Cell Carcinoma: A Review

Cancer stem cells (CSCs) have been identified in oral cavity squamous cell carcinoma (OCSCC). CSCs possess the ability for perpetual self-renewal and proliferation, producing downstream progenitor cells and cancer cells that drive tumor growth. Studies of many cancer types including OCSCC have identified CSCs using specific markers, but it is still unclear as to where in the stem cell hierarchy these markers fall. This is compounded further by the presence of multiple CSC subtypes within OCSCC, making investigation reliant on the use of multiple markers. This review examines the current knowledge in CSC markers OCT4, SOX2, NANOG, ALDH1, phosphorylated STAT3, CD44, CD24, CD133, and Musashi-1, specifically focusing on their use and validity in OCSCC CSC research and how they may be organized into the CSC hierarchy. OCSCC CSCs also express components of the renin–angiotensin system (RAS), which suggests CSCs may be novel therapeutic targets by modulation of the RAS using existing medications.

The optimal dose of arsenic trioxide induced opposite efficacy in autophagy between K562 cells and their initiating cells to eradicate human myelogenous leukemia

ETHNOPHARMACOLOGICAL RELEVANCE

Arsenic trioxide (As2O3), a main component of arsenolite which is a common traditional Chinese medicine (TCM) wildly used as a therapeutic agent for more than 2400 years in china, has been accepted as a standard treatment for the patients with acute promyelocytic leukemia (APL) based on the principle in TCM of "using a poison to fight against other poisons or malignancy illnesses". However, it remains unknown that which mechanism is actually responsible for the therapeutic effects against these blood malignancies.

AIM OF THE STUDY

The purpose of this study was to explore the actual mechanism that ATO exerts its effects in K562 cells and their initiating cells (K562s).

MATERIALS AND METHODS

K562s cells were separated and enriched for CD34+/CD38- cells using magnetic microbeads. Cell proliferation was determined by incorporation of BrdU. Cell apoptosis was evaluated by Annexin-V binding and PI uptake. Autophagy was estimated by acridine orange and immunofluorescence staining of LC3-B and p62. MC colonic formation was used to examine cell self-renew. ROS generation inside living cells was measured by DCFH-DA. Cell differentiation was assessed by the benzidine staining. The SA-β-gal assay was used to detect cell senescence. Protein expression was examined by western blotting and immunohistochemical staining.

RESULTS

K562s cells were stronger in self-renew and resistance to ATO cytotoxicity and starvation-induced apoptosis than K562 cells. Unexpectedly, we found that ATO at a dose of 0.5μM which had no effect on cell proliferation resulted in maximum suppression on self-renew in both cells and maximum starvation-induced apoptosis in K562s cells but minimum starvation-induced apoptosis in K562 cells. Next, we found that ATO no more than 0.5μM selectively induced K562s cell differentiation indicated by benzidine staining, γ-globin and CD235a expression. More importantly, we found that ATO no more than 0.5μM led to opposite efficacy in autophagy between K562 and K562s cells, and the opposite autophagy could induced late-phase senescence in both cells. Finally, we used the optimal dose of ATO to eradicate leukemia cells and obtained a satisfied therapeutic outcomes in vivo.

CONCLUSIONS

Our results suggest that the used dose of ATO may determine the fate of cell differentiation senescence or malignant transformation, and the optimal dose of ATO induced opposite efficacy in autophagy between K562 cells and their initiating cells and ultimately leads both cells to late-phase senescence.

Polycomb complex protein BMI-1 promotes invasion and metastasis of pancreatic cancer stem cells by activating PI3K/AKT signaling, an ex vivo, in vitro, and in vivo study

Cancer stem cell theory indicates cancer stem cells are the key to promote tumor invasion and metastasis. Studies showed that BMI-1 could promote self-renew, differentiation and tumor formation of CSCs and invasion/metastasis of human cancer. However, whether BMI-1 could regulate invasion and metastasis ability of CSCs is still unclear. In our study, we found that up-regulated expression of BMI-1 was associated with tumor invasion, metastasis and poor survival of pancreatic cancer patients. CD133+ cells were obtained by using magnetic cell sorting and identified of CSCs properties such as self-renew, multi-differentiation and tumor formation ability. Then, we found that BMI-1 expression was up-regulated in pancreatic cancer stem cells. Knockdown of BMI-1 expression attenuated invasion ability of pancreatic cancer stem cells in Transwell system and liver metastasis capacity in nude mice which were injected CSCs through the caudal vein. We are the first to reveal that BMI-1 could promote invasion and metastasis ability of pancreatic cancer stem cells. Finally, we identified that BMI-1 expression activating PI3K/AKT singing pathway by negative regulating PTEN was the main mechanism of promoting invasion and metastasis ability of pancreatic CSCs. In summary, our findings indicate that BMI-1 could be used as the therapeutic target to inhibiting CSCs-mediated pancreatic cancer metastasis.

Implications of cancer stem cells in developing therapeutic resistance in oral cancer

Conventional therapeutics are often frequented with recurrences, refraction and regimen resistance in oral cavity cancers which are predominantly manifested by cancer stem cells (CSCs). During oncoevolution, cancer cells may undergo structural and functional reprogramming wherein they evolve as highly tolerant CSC phenotypes with greater survival advantages. The CSCs possess inherent and exclusive properties including self-renewal, hierarchical differentiation, and tumorigenicity that serve as the basis of chemo-radio-resistance in oral cancer. However, the key mechanisms underlying the CSC-mediated therapy resistance need to be further elucidated. A spectrum of dysfunctional cellular pathways including the developmental signaling, apoptosis, autophagy, cell cycle regulation, DNA damage responses and epigenetic regulations protect the CSCs from conventional therapies. Moreover, tumor niche shelters CSCs and creates an immunosuppressive environment favoring the survival of CSCs. Maintenance of lower redox status, epithelial-to-mesenchymal transition (EMT), metabolic reprogramming and altered drug responses are the accessory features that aid in the process of chemo-radio-resistance in oral CSCs. This review deals with the functional and molecular basis of cancer cell pluripotency-associated resistance highlighting the abrupt fundamental cellular processes; targeting these events may hold a great promise in the successful treatment of oral cancer.

[Perioperative risk and mortality after major surgery]

Although anesthesia-associated mortality has been significantly reduced down to 0.00068-0.00082% over the last decades, recent studies have revealed a high perioperative mortality of 0.8- 4%. Apart from anesthesia and surgery-induced major complications, perioperative mortality is primarily negatively influenced by individual patient comorbidities. These risk factors predispose for acute critical incidents (e.g., myocardial infarction); however, the majority of fatal complications are a result of slowly progressing conditions, particularly infections or the sequelae of systemic inflammation. This implicates a broad window of opportunity for the detection and treatment of slow-onset complications to improve the perioperative outcome. The term "failure to rescue" (FTR), i.e., the proportion of patients who die from major complications compared to the number of all patients with complications, has been introduced as a valid indicator for the quality of perioperative care. Growing evidence has already shown that FTR is an underestimated factor in perioperative medicine accounting for or at least being involved in the development of postoperative mortality. While the incidence of severe postoperative complications amazingly does not show much variation between hospitals, FTR shows significant differences implying a major potential for improvement. With 14 million surgical procedures per year in Germany, a postoperative mortality of approximately 1% and an avoidable FTR rate of 40% mean that there are an estimated 60,000 preventable deaths per year. Hence, in the future it will be imperative to (1) identify patients at risk, (2) to prevent the development of postoperative complications with the use of adequate adjunctive therapeutic strategies, (3) to establish surveillance and monitoring systems for the early detection of postoperative complications and (4) to treat postoperative complications efficiently and in time when they arise.