Identification of cisplatin-resistance related genes in head and neck squamous cell carcinoma

miR-135b-5p/PDE3B Axis Regulates Gemcitabine Resistance in Pancreatic Cancer Through Epithelial-Mesenchymal Transition

Gemcitabine-based chemotherapy is an effective treatment for pancreatic cancer (PC), but gemcitabine resistance frequently compromises the therapeutic efficacy, resulting in clinical chemotherapeutic failure and a poor prognosis for patients. In this study, we investigated the mechanisms of gemcitabine chemoresistance in PC by examining the roles of microRNAs linked to gemcitabine resistance and their downstream signaling pathways. In vitro experiments were performed to alter miR-135b-5p levels in PC parental and drug-resistant cells to probe its function. miR-135b-5p targets PDE3B was confirmed by using RNA-seq technology to screen for gemcitabine-resistance-associated mRNAs in PC. A series of rescue experiments were performed after cotransfection, demonstrating that PDE3B could reverse miR-135b-5p-mediated chemoresistance and epithelial-mesenchymal transition (EMT). These findings indicate that the miR-135b-5p/PDE3B axis generates resistance by stimulating the EMT signaling pathway, which provides new insights into gemcitabine chemoresistance in PC.

Chromatin remodeling-driven autophagy activation induces cisplatin resistance in oral squamous cell carcinoma

It is still challenging to predict the efficacy of cisplatin-based therapy, particularly in relation to the activation of macroautophagy/autophagy in oral squamous cell carcinoma (OSCC). We studied the effect of selected chromatin remodeling genes on the cisplatin resistance and their interplay with autophagy in 3-dimensional tumor model and xenografts. We analyzed gene expression patterns in the cisplatin-sensitive UMSCC1, and a paired cisplatin-resistant UM-Cis cells. Many histone protein gene clusters involved in nucleosome assembly showed significant difference of expression. Gain- and loss-of-function analyses revealed an inverse correlation between cisplatin resistance and HIST1H3D expression, while a positive correlation was observed with HIST3H2A or HIST3H2B expression. In UM-Cis, HIST3H2A- and HIST3H2B-mediated chromatin remodeling upregulates autophagy status, which results in cisplatin resistance. Additionally, knockdown of HIST3H2A or HIST3H2B downregulated autophagy-activating genes via chromatin compaction of their promoter regions. MiTF, one of the key autophagy regulators upregulated in UM-Cis, negatively regulated transcription of HIST1H3D, suggesting an interplay between chromatin remodeling-dependent cisplatin resistance and autophagy. On comparing the staining intensity between cisplatin-sensitive and -insensitive tissues from OSCC patients, protein expression pattern of the selected histone protein genes were matched with the in vitro data. By examining the relationship between autophagy and chromatin remodeling genes, we identified a set of candidate genes with potential use as markers predicting chemoresistance in OSCC biopsy samples.

3D stem-like spheroids-on-a-chip for personalized combinatorial drug testing in oral cancer

BACKGROUND

Functional drug testing (FDT) with patient-derived tumor cells in microfluidic devices is gaining popularity. However, the majority of previously reported microfluidic devices for FDT were limited by at least one of these factors: lengthy fabrication procedures, absence of tumor progenitor cells, lack of clinical correlation, and mono-drug therapy testing. Furthermore, personalized microfluidic models based on spheroids derived from oral cancer patients remain to be thoroughly validated. Overcoming the limitations, we develop 3D printed mold-based, dynamic, and personalized oral stem-like spheroids-on-a-chip, featuring unique serpentine loops and flat-bottom microwells arrangement.

RESULTS

This unique arrangement enables the screening of seven combinations of three drugs on chemoresistive cancer stem-like cells. Oral cancer patients-derived stem-like spheroids (CD 44+) remains highly viable (> 90%) for 5 days. Treatment with a well-known oral cancer chemotherapy regimen (paclitaxel, 5 fluorouracil, and cisplatin) at clinically relevant dosages results in heterogeneous drug responses in spheroids. These spheroids are derived from three oral cancer patients, each diagnosed with either well-differentiated or moderately-differentiated squamous cell carcinoma. Oral spheroids exhibit dissimilar morphology, size, and oral tumor-relevant oxygen levels (< 5% O2). These features correlate with the drug responses and clinical diagnosis from each patient's histopathological report.

CONCLUSIONS

Overall, we demonstrate the influence of tumor differentiation status on treatment responses, which has been rarely carried out in the previous reports. To the best of our knowledge, this is the first report demonstrating extensive work on development of microfluidic based oral cancer spheroid model for personalized combinatorial drug screening. Furthermore, the obtained clinical correlation of drug screening data represents a significant advancement over previously reported personalized spheroid-based microfluidic devices. Finally, the maintenance of patient-derived spheroids with high viability under oral cancer relevant oxygen levels of less than 5% O2 is a more realistic representation of solid tumor microenvironment in our developed device.

The response and resistance to drugs in ovarian cancer cell lines in 2D monolayers and 3D spheroids

Ovarian cancer is the most common type of gynecologic cancer. One of the leading causes of high mortality is chemoresistance, developed primarily or during treatment. Different mechanisms of drug resistance appear at the cellular and cancer tissue organization levels. We examined the differences in response to the cytotoxic drugs CIS, MTX, DOX, VIN, PAC, and TOP using 2D (two-dimensional) and 3D (three-dimensional) culture methods. We tested the drug-sensitive ovarian cancer cell line W1 and established resistant cell lines to appropriate cytotoxic drugs. The following qualitative and quantitative methods were used to assess: 1) morphology - inverted microscope and hematoxylin & eosin staining; 2) viability - MTT assay; 3) gene expression - a quantitative polymerase chain reaction; 4) identification of proteins - immunohistochemistry, and immunofluorescence. Our results indicate that the drug-sensitive and drug-resistant cells cultured in 3D conditions exhibit stronger resistance than the cells cultured in 2D conditions. A traditional 2D model shows that drug resistance of cancer cells is caused mainly by changes in the expression of genes encoding ATP-binding cassette transporter proteins, components of the extracellular matrix, "new" established genes related to drug resistance in ovarian cancer cell lines, and universal marker of cancer stem cells. Whereas in a 3D model, the drug resistance in spheroids can be related to other mechanisms such as the structure of the spheroid (dense or loose), the cell type (necrotic, quiescent, proliferating cells), drug concentrations or drug diffusion into the dense cellular/ECM structure.

Identification of transcriptional programs using dense vector representations defined by mutual information with GeneVector

Deciphering individual cell phenotypes from cell-specific transcriptional processes requires high dimensional single cell RNA sequencing. However, current dimensionality reduction methods aggregate sparse gene information across cells, without directly measuring the relationships that exist between genes. By performing dimensionality reduction with respect to gene co-expression, low-dimensional features can model these gene-specific relationships and leverage shared signal to overcome sparsity. We describe GeneVector, a scalable framework for dimensionality reduction implemented as a vector space model using mutual information between gene expression. Unlike other methods, including principal component analysis and variational autoencoders, GeneVector uses latent space arithmetic in a lower dimensional gene embedding to identify transcriptional programs and classify cell types. In this work, we show in four single cell RNA-seq datasets that GeneVector was able to capture phenotype-specific pathways, perform batch effect correction, interactively annotate cell types, and identify pathway variation with treatment over time.

Lumican is a potential predictor on the efficacy of concurrent chemoradiotherapy in cervical squamous cell carcinoma

Purpose

To identify new novel biomarkers for predicting the efficacy of concurrent chemoradiotherapy(CCRT) in cervical squamous cell carcinoma(CESC).

Methods

Gene expression datasets GSE56363, GSE5787, and GSE168009 were analyzed to identify candidate genes to predict the efficacy of CCRT in CESC. Single-cell RNA sequencing (scRNA-seq) data from GSE168652 and CESC patients in The Cancer Genome Atlas(TCGA) were systematically analyzed to explore possible molecular mechanisms. Kaplan-Meier evaluated the correlation between LUM (Lumican) and prognostic significance. The expression of LUM protein in biopsy tissues before CCRT was detected by immunohistochemistry in 15 CESC patients.

Results

LUM mRNA levels were significantly upregulated in nonresponders of CESC.patients receiving CCRT and positively correlated with poor therapeutic effect. Furthermore, high expression of LUM influenced the immune microenvironment in CESC patient-derived organoids treated with CCRT. LUM overexpression in CESC cells induced resistance to CCRT, potentially via immune landscape modulation. Gene Set Enrichment Analysis (GSEA) revealed that possible mechanisms underlying resistance to CCRT might involve the PARs and IL1 signaling pathway affecting the immune landscape.

Conclusions

High LUM expression is correlated with poor efficacy in CESC patients receiving CCRT, possibly through the PARs and IL1 signaling pathway affecting the immune landscape.

Cisplatin-induced increase in heregulin 1 and its attenuation by the monoclonal ErbB3 antibody seribantumab in bladder cancer

Cisplatin-based combination chemotherapy is the foundation for treatment of advanced bladder cancer (BlCa), but many patients develop chemoresistance mediated by increased Akt and ERK phosphorylation. However, the mechanism by which cisplatin induces this increase has not been elucidated. Among six patient-derived xenograft (PDX) models of BlCa, we observed that the cisplatin-resistant BL0269 express high epidermal growth factor receptor, ErbB2/HER2 and ErbB3/HER3. Cisplatin treatment transiently increased phospho-ErbB3 (Y1328), phospho-ERK (T202/Y204) and phospho-Akt (S473), and analysis of radical cystectomy tissues from patients with BlCa showed correlation between ErbB3 and ERK phosphorylation, likely due to the activation of ERK via the ErbB3 pathway. In vitro analysis revealed a role for the ErbB3 ligand heregulin1-β1 (HRG1/NRG1), which is higher in chemoresistant lines compared to cisplatin-sensitive cells. Additionally, cisplatin treatment, both in PDX and cell models, increased HRG1 levels. The monoclonal antibody seribantumab, that obstructs ErbB3 ligand-binding, suppressed HRG1-induced ErbB3, Akt and ERK phosphorylation. Seribantumab also prevented tumor growth in both the chemosensitive BL0440 and chemoresistant BL0269 models. Our data demonstrate that cisplatin-associated increases in Akt and ERK phosphorylation is mediated by an elevation in HRG1, suggesting that inhibition of ErbB3 phosphorylation may be a useful therapeutic strategy in BlCa with high phospho-ErbB3 and HRG1 levels.

SHMT2 Induces Stemness and Progression of Head and Neck Cancer

Various enzymes in the one-carbon metabolic pathway are closely related to the development of tumors, and they can all be potential targets for cancer therapy. Serine hydroxymethyltransferase2 (SHMT2), a key metabolic enzyme, is very important for the proliferation and growth of cancer cells. However, the function and mechanism of SHMT2 in head and neck cancer (HNC) are not clear. An analysis of The Cancer Genome Atlas (TCGA) data showed that the expression of SHMT2 was higher in tumor tissue than in normal tissue, and its expression was significantly associated with male sex, aggressive histological grade, lymph node metastasis, distant metastasis, advanced TNM stage, and lymphovascular invasion in HNC. SHMT2 knockdown in FADU and SNU1041 cell lines significantly inhibited cell proliferation, colony formation, migration, and invasion. Additionally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses using TCGA data revealed that SHMT2 was closely related to cancer stem cell regulation and maintenance. Furthermore, we found that silencing SHMT2 inhibited the expression of stemness markers and tumor spheroid formation compared with a control group. On the contrary, stemness markers were significantly increased after SHMT2 overexpression in HEP-2 cells. Interestingly, we found that knocking down SHMT2 reduced the expression of genes related to the Notch and Wnt pathways. Finally, silencing SHMT2 significantly reduced tumor growth and decreased stemness markers in a xenograft model. Taken together, our study suggests that targeting SHMT2 may play an important role in inhibiting HNC progression.

The Yin and Yang of ERBB4: Tumor Suppressor and Oncoprotein

ERBB4 (HER4) is a member of the ERBB family of receptor tyrosine kinases, a family that includes the epidermal growth factor receptor (EGFR/ERBB1/HER1), ERBB2 (Neu/HER2), and ERBB3 (HER3). EGFR and ERBB2 are oncoproteins and validated targets for therapeutic intervention in a variety of solid tumors. In contrast, the role that ERBB4 plays in human malignancies is ambiguous. Thus, here we review the literature regarding ERBB4 function in human malignancies. We review the mechanisms of ERBB4 signaling with an emphasis on mechanisms of signaling specificity. In the context of this signaling specificity, we discuss the hypothesis that ERBB4 appears to function as a tumor suppressor protein and as an oncoprotein. Next, we review the literature that describes the role of ERBB4 in tumors of the bladder, liver, prostate, brain, colon, stomach, lung, bone, ovary, thyroid, hematopoietic tissues, pancreas, breast, skin, head, and neck. Whenever possible, we discuss the possibility that ERBB4 mutants function as biomarkers in these tumors. Finally, we discuss the potential roles of ERBB4 mutants in the staging of human tumors and how ERBB4 function may dictate the treatment of human tumors. SIGNIFICANCE STATEMENT: This articles reviews ERBB4 function in the context of the mechanistic model that ERBB4 homodimers function as tumor suppressors, whereas ERBB4-EGFR or ERBB4-ERBB2 heterodimers act as oncogenes. Thus, this review serves as a mechanistic framework for clinicians and scientists to consider the role of ERBB4 and ERBB4 mutants in staging and treating human tumors.

Current Omics Trends in Personalised Head and Neck Cancer Chemoradiotherapy

Chemoradiotherapy remains the most common management of locally advanced head and neck cancer. While both treatment components have greatly developed over the years, the quality of life and long-term survival of patients undergoing treatment for head and neck malignancies are still poor. Research in head and neck oncology is equally focused on the improvement of tumour response to treatment and on the limitation of normal tissue toxicity. In this regard, personalised therapy through a multi-omics approach targeting patient management from diagnosis to treatment shows promising results. The aim of this paper is to discuss the latest results regarding the personalised approach to chemoradiotherapy of head and neck cancer by gathering the findings of the newest omics, involving radiotherapy (dosiomics), chemotherapy (pharmacomics), and medical imaging for treatment monitoring (radiomics). The incorporation of these omics into head and neck cancer management offers multiple viewpoints to treatment that represent the foundation of personalised therapy.

Clinical Significance and Prognostic Value of SOX2 Protein Expression in Patients With Oral Squamous Cell Carcinoma

OBJECTIVES

Cancer stem cells are a small group of highly tumorigenic cells with the trend of self-renewal, tumor progression, metastasis, recurrence, and therapeutic resistance. SOX2 is an important cancer stem cell marker that is involved in tumorigenesis and correlated with aggressive features in various types of malignancies. The present study was aimed to investigate the expression of this biomarker in neoplastic tissues of oral squamous cell carcinoma (OSCC) to determine whether it has the potential to predict the outcomes and survival of the affected patients.

MATERIALS AND METHODS

The medical records of 73 patients diagnosed with OSCC were retrospectively studied. Clinical and pathologic features included age, sex, tumor size, histologic grade, lymph node involvement, recurrence, metastasis, and follow up. Immunohistochemical analysis for SOX2 protein expression was performed, and its correlations with clinicopathologic features were evaluated.

RESULTS

SOX2 was significantly associated with tumor size, lymph node metastasis, and patients' survival. We found no apparent correlation between SOX2 and tumor recurrence, distant metastasis, or differentiation. The multivariate analysis identifies patients' age, sex, and SOX2 expression as independent prognostic factors for overall survival.

CONCLUSION

SOX2 may worsen the prognosis and be a progressive malignant factor, which can help clinicians investigate OSCC patients' survival and plan the appropriate treatment accordingly.

Systematic screening identifies a TEAD4-S100A13 axis modulating cisplatin sensitivity of oral squamous cell carcinoma cells

BACKGROUND

This study aimed to screen prognosis-related S100 protein family members in human paxpillomaviruses (HPV)-negative oral squamous cell carcinoma (OSCC) and their molecular regulations.

METHODS

Bioinformatic screening was conducted based on single-cell RNA-seq data from Puram 2017 dataset and bulk-seq data from the Cancer Genome Atlas (TCGA). HPV-negative OSCC cell lines CAL-27 and SCC-4 were used as in vitro cell models.

RESULTS

Among 21 S100 protein family member genes, S100A13 upregulation was associated with unfavorable progression-free survival and disease-specific survival of OSCC patients. Gene Set Enrichment Analysis showed that the higher S100A13 expression group had elevated genes enriched in DNA repair and oxidative phosphorylation. S100A13 knockdown increased cisplatin sensitivity, while its overexpression decreased the sensitivity of CAL-27 and SCC-4 cells. S100A13 gene had complex alternative transcription patterns. ENST00000440685 is one of the major protein-coding transcripts and was the only transcript elevated in the tumor group. TEAD4 could bind to the promoter of ENST00000440685 and increase its transcription. TEAD4 overexpression alleviated the tumor-suppressive effect of cisplatin in terms of colony formation, the expression of apoptotic proteins, and DNA damage. However, S100A13 knockdown partly abrogated the protective effects of TEAD4 overexpression.

CONCLUSION

This study revealed a novel TEAD4-S100A13 axis that might modulate cisplatin sensitivity of OSCC tumor cells.

Cisplatin and phenanthriplatin modulate long-noncoding RNA expression in A549 and IMR90 cells revealing regulation of microRNAs, Wnt/β-catenin and TGF-β signaling

The monofunctional platinum(II) complex, phenanthriplatin, acts by blocking transcription, but its regulatory effects on long-noncoding RNAs (lncRNAs) have not been elucidated relative to traditional platinum-based chemotherapeutics, e.g., cisplatin. Here, we treated A549 non-small cell lung cancer and IMR90 lung fibroblast cells for 24 h with either cisplatin, phenanthriplatin or a solvent control, and then performed microarray analysis to identify regulated lncRNAs. RNA22 v2 microRNA software was subsequently used to identify microRNAs (miRNAs) that might be suppressed by the most regulated lncRNAs. We found that miR-25-5p, -30a-3p, -138-5p, -149-3p, -185-5p, -378j, -608, -650, -708-5p, -1253, -1254, -4458, and -4516, were predicted to target the cisplatin upregulated lncRNAs, IMMP2L-1, CBR3-1 and ATAD2B-5, and the phenanthriplatin downregulated lncRNAs, AGO2-1, COX7A1-2 and SLC26A3-1. Then, we used qRT-PCR to measure the expression of miR-25-5p, -378j, -4516 (A549) and miR-149-3p, -608, and -4458 (IMR90) to identify distinct signaling effects associated with cisplatin and phenanthriplatin. The signaling pathways associated with these miRNAs suggests that phenanthriplatin may modulate Wnt/β-catenin and TGF-β signaling through the MAPK/ERK and PTEN/AKT pathways differently than cisplatin. Further, as some of these miRNAs may be subject to dissimilar lncRNA targeting in A549 and IMR90 cells, the monofunctional complex may not cause toxicity in normal lung compared to cancer cells by acting through distinct lncRNA and miRNA networks.

Neferine promotes the apoptosis of HNSCC through the accumulation of p62/SQSTM1 caused by autophagic flux inhibition

Head and neck squamous cell carcinoma (HNSCC), one of the most common malignancies worldwide, often has a poor prognosis due to the associated metastasis and chemoresistance. Hence, the development of more effective chemotherapeutics is critical. Neferine, a bisbenzylisoquinoline alkaloid isolated from the seed embryo of Nelumbo nucifera (common name: Lotus), exerts antitumor effects by regulating apoptosis and autophagy pathways, making it a potential therapeutic option for HNSCC. In our study, it was revealed that neferine inhibited the growth and induced the apoptosis of HNSCC cells both in vitro and in vivo. Furthermore, the results revealed that neferine activated the ASK1/JNK pathway by increasing reactive oxygen species production, resulting in the subsequent induction of apoptosis and the regulation of canonical autophagy in HNSCC cells. Moreover, a novel pro‑apoptotic mechanism was described for neferine via the activation of caspase‑8 following the accumulation of p62, which was caused by autophagic flux inhibition. These findings provided insights into the mechanisms responsible for the anticancer effect of neferine, specifically highlighting the crosstalk that occured between apoptosis and autophagy, which was mediated by p62 in HNSCC. Hence, the neferine‑induced inhibition of autophagic flux may serve as the basis for a potential adjuvant therapy for HNSCC.

Involvement of miR-619-5p in resistance to cisplatin by regulating ATXN3 in oral squamous cell carcinoma

MicroRNAs are major post-transcriptional regulators responsible for the development of human cancers, including OSCC. The specific role of miR-619-5p in OSCC, however, is rarely reported. Cisplatin is one of the mostly applied chemotherapy drugs of OSCC. Nevertheless, drug resistance of cisplatin following the initial chemotherapy largely restricts its clinical benefits, and the mechanism of cisplatin resistance is unclear. This study intends to explore the biological function of miR-619-5p in the development of cisplatin resistance in OSCC cell lines and a xenograft model, as well as the potential molecular mechanism. Our results showed that miR-619-5p was down-regulated in OSCC samples and cisplatin-resistant OSCC cells. Ectopically expressed miR-619-5p inhibited proliferative, migratory and invasive abilities of OSCC cisplatin-resistant cells. The putative target gene ATXN3 was predicted by bioinformatic analysis and confirmed by dual-luciferase reporter assay. Importantly, ATXN3 was responsible for the regulatory effects of miR-619-5p on biological behaviors of cisplatin-resistant OSCC cells. Moreover, miR-619-5p mimics and ATXN3-siRNA significantly enhanced ATXN3 knockdown in both HN6/CDDPR and CAL27/CDDPR cells and inhibited expression of PI3K and AKT. In vivo evidences demonstrated that intratumoral injection of miR-619-5p agomir remarkably slowed down the growth of OSCC in xenograft mice. Collectively, microRNA-619-5p was the vital regulator for regulating cisplatin resistance of OSCC, which may be served as a potential therapeutic target.

Current and Future Therapeutic Targets: A Review on Treating Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) continues to be a global public health burden even after a tremendous development in its treatment. It is a heterogeneous cancer of upper aero-digestive tract. The contemporary strategy to treat cancer is the use of anticancer drugs against proteins possessing abnormal expression. Targeted chemotherapy was found successful in HNSCC, but, there is still a stagnant improvement in the survival rates and high recurrence rates due to undesirable chemotherapy reactions, non-specificity of drugs, resistance against drugs and drug toxicity on non-cancerous tissues and cells. Various extensive studies lead to the identification of drug targets capable to treat HNSCC effectively. The current review article gives an insight into these promising anticancer targets along with knowledge of drugs under various phases of development. In addition, new potential targets that are not yet explored against HNSCC are also described. We believe that exploring and developing drugs against these targets might prove beneficial in treating HNSCC.

RNA-Seq Analysis of Cisplatin and the Monofunctional Platinum(II) Complex, Phenanthriplatin, in A549 Non-Small Cell Lung Cancer and IMR90 Lung Fibroblast Cell Lines

Phenanthriplatin is a new monofunctional platinum(II) complex that binds only one strand of DNA and acts by blocking gene transcription, but its effect on gene regulation has not been characterized relative to the traditional platinum-based complex, cisplatin. A549 non-small cell lung cancer and IMR90 lung fibroblast cells were treated with cisplatin, phenanthriplatin, or a control and then their RNA transcripts were subjected to next generation sequencing analysis. DESeq2 and CuffDiff2 were used to identify up- and downregulated genes and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were used to identify pathways and functions. We found that phenanthriplatin may regulate the genes GPRC5a, TFF1, and TNFRSF10D, which act through p53 to control apoptosis, differently or to a greater extent than cisplatin, and that it, unlike cisplatin, could upregulate ATP5MD, a gene which signals through the Wnt/β catenin pathway. Furthermore, phenanthriplatin caused unique or enhanced effects compared to cisplatin on genes regulating the cytoskeleton, cell migration, and proliferation, e.g., AGAP1, DIAPH2, GDF15, and THSD1 (p < 0.05; q < 0.05). Phenanthriplatin may modulate some oncogenes differently than cisplatin potentially leading to improved clinical outcome, but this monofunctional complex should be carefully matched with cancer gene data to be successfully applied in chemotherapy.

Prognostic Implication of SOX2 Expression Associated with p16 in Oropharyngeal Cancer: A Study of Consecutive Tissue Microarrays and TCGA

Simple Summary

The role of human papillomavirus (HPV) in oropharyngeal cancer (OPSCC) as a cause agent has been reported in much of the literature. As a surrogate marker, p16 immunohistochemical staining is used as the standard for classifying OPSCC, and the prognosis of p16+ OPSCC has been reported to be better than p16− OPSCC. However, it was necessary to study what is the next biomarker that could predict the prognosis after classification by p16. We assumed that SOX2 may be a potential biomarker. For each p16+ and p16− OPSCC, SOX2 was used to analyze whether the degree of expression level differed in survival and recurrence rates. The results showed that both immunohistochemical staining and mRNA expression level of SOX2 significantly affected the survival and recurrence rates of p16+ OPSCC patients in two different datasets which were constructed in differently ways. Our study presented the clinical applicability of SOX2 as a biomarker.

Abstract

For oropharyngeal squamous cell carcinoma (OPSCC), there are not enough additional robust biomarkers for subgrouping after the distinct classification using p16. As SOX2 is an emerging biomarker for cancer treatment, its clinical implication in OPSCC was evaluated using a consecutive tissue microarray (TMA) cohort consisting of 111 patients who underwent surgery as an initial treatment from May 2002 to December 2016 and 79 patients in The Cancer Genome Atlas (TCGA) dataset. In both datasets, p16+/SOX2^High (HPV+/SOX2^High in TCGA) showed the best prognosis among the four groups classified by SOX2 and p16 for 5-year overall survival (OS) and recurrence (all p < 0.05), but SOX2 did not make a significant difference in the prognosis of the p16− group. In the TMA cohort, SOX2^High was significantly correlated with response to radiotherapy and lower pathologic T classification in the p16+ group (p = 0.001). In TCGA, correlations between SOX2 and tumor stage classification or radiotherapy were not observed; however, HPV+/SOX2^High had a significantly low tumor mutation burden among the four groups (all p < 0.05). In summary, SOX2 was proven to be a potential marker to predict overall survival and recurrence in p16+ OPSCC. However, the role of SOX2 has not yet been confirmed in p16− OPSCC patients.

Paclitaxel exposure downregulates miR-522 expression and its downregulation induces paclitaxel resistance in ovarian cancer cells

Paclitaxel resistance is a critical challenge in ovarian cancer treatment. This study aimed to identify microRNAs (miRNAs) that modulate paclitaxel resistance for use as potential therapeutic targets in such settings. Paclitaxel-resistant cell lines were established using two ovarian cancer cell lines: SKOV3ip1 and HeyA8. The evaluation of miRNA polymerase chain reaction (PCR) arrays indicated that the expression of miR-522-3p was downregulated in paclitaxel-resistant cells. The restoration of miR-522-3p sensitized the resistant cells to paclitaxel, and its downregulation desensitized the parental cells. Using PCR arrays, we focused on E2F2, with the luciferase reporter assay revealing that it was a direct target for miR-522-3p. The paclitaxel-resistant cells showed stronger E2F2 expression than the parental cells, while E2F2 inhibition sensitized the resistant cells to paclitaxel. Forced E2F2 expression in the parental cells led to the acquisition of paclitaxel resistance, while miR-522-3p inhibited E2F2 expression and was associated with retinoblastoma protein phosphorylation attenuation, which resulted in G0/G1 arrest. The effects of miR-522-3p and E2F2 in ovarian cancer were examined using public databases, revealing that low miR-522-3p expression and high E2F2 expression were associated with significantly poorer overall survival. In conclusion, miR-522-3p attenuated the degree of paclitaxel resistance in vitro through the downregulation of E2F2; miR-522-3p supplementation may be a therapeutic target for paclitaxel-resistant ovarian cancer.

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors' platinum resistance identifies novel approach to treating these tumors.

Transcriptomic Profiling Identifies Differentially Expressed Genes in Palbociclib-Resistant ER+ MCF7 Breast Cancer Cells

Acquired resistance to cyclin-dependent kinases 4 and 6 (CDK4/6) inhibition in estrogen receptor-positive (ER+) breast cancer remains a significant clinical challenge. Efforts to uncover the mechanisms underlying resistance are needed to establish clinically actionable targets effective against resistant tumors. In this study, we sought to identify differentially expressed genes (DEGs) associated with acquired resistance to palbociclib in ER+ breast cancer. We performed next-generation transcriptomic RNA sequencing (RNA-seq) and pathway analysis in ER+ MCF7 palbociclib-sensitive (MCF7/pS) and MCF7 palbociclib-resistant (MCF7/pR) cells. We identified 2183 up-regulated and 1548 down-regulated transcripts in MCF7/pR compared to MCF7/pS cells. Functional analysis of the DEGs using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database identified several pathways associated with breast cancer, including ‘cell cycle’, ‘DNA replication’, ‘DNA repair’ and ‘autophagy’. Additionally, Ingenuity Pathway Analysis (IPA) revealed that resistance to palbociclib is closely associated with deregulation of several key canonical and metabolic pathways. Further studies are needed to determine the utility of these DEGs and pathways as therapeutics targets against ER+ palbociclib-resistant breast cancer.

Periodic Oxaliplatin Administration in Synergy with PER2-Mediated PCNA Transcription Repression Promotes Chronochemotherapeutic Efficacy of OSCC

Developing chemotherapeutic resistance affects clinical outcomes of oxaliplatin treatment on various types of cancer. Thus, it is imperative to explore alternative therapeutic strategies to improve the efficacy of oxaliplatin. Here, it is shown that circadian regulator period 2 (PER2) can potentiate the cytotoxicity of oxaliplatin and boost cell apoptosis by inhibiting DNA adducts repair in human oral squamous cell carcinoma (OSCC) cells. The circadian timing system is closely involved in controling the activity of DNA adducts repair and gives it a 24 h rhythm. The mechanistic dissection clarifies that PER2 can periodically suppress proliferating cell nuclear antigen (PCNA) transcription by pulling down circadian locomotor output cycles kaput-brain and muscle arnt-like 1 heterodimer from PCNA promoter in a CRY1/2-dependent manner, which subsequently impedes oxaliplatin-induced DNA adducts repair. Similarly, PER2 is capable of improving the efficacy of classical DNA-damaging chemotherapeutic agents. The tumor-bearing mouse model displays PER2 can be deployed as an oxaliplatin administration timing biomarker. In summary, it is believed that the chronochemotherapeutic strategy matching PER2 expression rhythm can efficiently improve the oxaliplatin efficacy of OSCC.

Psorachromene Suppresses Oral Squamous Cell Carcinoma Progression by Inhibiting Long Non-coding RNA GAS5 Mediated Epithelial-Mesenchymal Transition

The extract of the seeds of Psoralea corylifolia Linn. (P. corylifolia) have been shown to display anti-tumor activity. However, the prospects of the active compounds from this plant in the treatment of oral squamous cell carcinoma (OSCC) remains unclear. In the present study, the antitumor effects of psorachromene, a flavonoid extracted from the seeds of P. corylifolia, were investigated using cells and animal models of OSCC; the downstream regulatory mechanisms were also elucidated. The results showed that psorachromene significantly repressed cell proliferation, migration, and invasiveness and increased the toxic effects of chemotherapeutic agents against OSCC cells. The repressive effects of psorachromene were attributable to the inhibition of EGFR-Slug signaling, and the induction of G2/M arrest and apoptosis in the OSCC cells. Additionally, we found that psorachromene induced the expression of tumor suppressor long non-coding ribonucleic acid (RNA) growth arrest-specific transcript 5 (GAS5) and the activation of its downstream anticancer mechanisms. Animal experiments also showed noticeable inhibition of tumor growth, without significant physiological toxicity. The findings indicate that psorachromene displays anti-tumor activity in OSCC, and warrants further investigation as a potential agent for clinical application.

Construction of Novel DNA Methylation-Based Prognostic Model to Predict Survival in Glioblastoma

Glioblastoma (GBM) is a most aggressive primary cancer in brain with poor prognosis. This study aimed to identify novel tumor biomarkers with independent prognostic values in GBMs. The DNA methylation profiles were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus database. Differential methylated genes (DMGs) were screened from recurrent GBM samples using limma package in R software. Functional enrichment analysis was performed to identify major biological processes and signaling pathways. Furthermore, critical DMGs associated with the prognosis of GBM were screened according to univariate and multivariate cox regression analysis. A risk score-based prognostic model was constructed for these DMGs and prediction ability of this model was validated in training and validation data set. In total, 495 DMGs were identified between recurrent samples and disease-free samples, including 356 significantly hypermethylated and 139 hypomethylated genes. Functional and pathway items for these DMGs were mainly related to sensory organ development, neuroactive ligand-receptor interaction, pathways in cancer, etc. Five genes with abnormal methylation level were significantly correlated with prognosis according to survival analysis, such as ALX1, KANK1, NUDT12, SNED1, and SVOP. Finally, the risk model provided an effective ability for prognosis prediction both in training and validation data set. We constructed a novel prognostic model for survival prediction of GBMs. In addition, we identified five DMGs as critical prognostic biomarkers in GBM progression.

An oncogenic activity of PDGF-C and its splice variant in human breast cancer

Despite strong evidence for the involvement of PDGF signaling in breast cancer, little is known about the PDGF ligand responsible for PDGFR activation during breast cancer progression. Here, we found PDGF-C to be highly expressed in breast carcinoma cell lines. Immunohistochemical analysis of invasive breast cancer revealed an association between increased PDGF-C expression and lymph node metastases, Ki-67 proliferation index, and poor disease-free survival. We also identified a PDGF-C splice variant encoding truncated PDGF-C (t-PDGF-C) isoform lacking the signal peptide and the N-terminal CUB domain. While t-PDGF C homodimer is retained intracellularly, it can be secreted as a heterodimer with full-length PDGF-C (FL-PDGF-C). PDGF-C downregulation reduced anchorage-independent growth and matrigel invasion of MDA-MB-231 cells. Conversely, ectopic expression of t-PDGF-C enhanced phenotypic transformation and invasion in BT-549 cells expressing endogenous FL-PDGF-C. The present study provides new insights into the functional significance of PDGF-C and its splice variant in human breast cancer.

Upregulation of MDR- and EMT-Related Molecules in Cisplatin-Resistant Human Oral Squamous Cell Carcinoma Cell Lines

Cisplatin is one of the major drugs used in oral cancer treatments, but its usage can be limited by acquired drug resistance. In this study, we established three cisplatin-resistant oral squamous cell carcinoma (OSCC) cell lines and characterized them using cell viability assays, qPCR, Western blotting, FACS, immunofluorescence, and wound healing assays. Three OSCC cell lines (YD-8, YD-9, and YD-38) underwent long-term exposure to cisplatin, eventually acquiring resistance to the drug, which was confirmed by an MTT assay. In these three newly established cell lines (YD-8/CIS, YD-9/CIS, and YD-38/CIS), overexpression of multidrug resistance (MDR)-related genes was detected by qPCR and Western blotting. The cell lines displayed an increase in the functional activities of breast cancer resistance protein (BCRP) and multidrug resistance protein1 (MDR1) by rhodamine 123 and bodipy FL prazosin accumulation assays. Moreover, the cisplatin-resistant cells underwent morphological changes, from round to spindle-shaped, increased expression of epithelial-to-mesenchymal transition (EMT)-related molecules such as N-cadherin, and showed increased cell migration when compared with the parental cell lines. These results suggest that these newly established cell lines have acquired drug resistance and EMT induction.

Melatonin Enhances Cisplatin and Radiation Cytotoxicity in Head and Neck Squamous Cell Carcinoma by Stimulating Mitochondrial ROS Generation, Apoptosis, and Autophagy

Head and neck cancer is the sixth leading cancer by incidence worldwide. Unfortunately, drug resistance and relapse are the principal limitations of clinical oncology for many patients, and the failure of conventional treatments is an extremely demoralizing experience. It is therefore crucial to find new therapeutic targets and drugs to enhance the cytotoxic effects of conventional treatments without potentiating or offsetting the adverse effects. Melatonin has oncostatic effects, although the mechanisms involved and doses required remain unclear. The purpose of this study is to determine the precise underlying mitochondrial mechanisms of melatonin, which increase the cytotoxicity of oncological treatments, and also to propose new melatonin treatments in order to alleviate and reverse radio- and chemoresistant processes. We analyzed the effects of melatonin on head and neck squamous cell carcinoma (HNSCC) cell lines (Cal-27 and SCC-9), which were treated with 0.1, 0.5, 1, and 1.5 mM melatonin combined with 8 Gy irradiation or 10 μM cisplatin. Clonogenic and MTT assays, as well as autophagy and apoptosis, involving flow cytometry and western blot, were performed in order to determine the cytotoxic effects of the treatments. Mitochondrial function was evaluated by measuring mitochondrial respiration, mtDNA content (RT-PCR), and mitochondrial mass (NAO). ROS production, antioxidant enzyme activity, and GSH/GSSG levels were analyzed using a fluorometric method. We show that high concentrations of melatonin potentiate the cytotoxic effects of radiotherapy and CDDP in HNSCC, which are associated with increased mitochondrial function in these cells. In HNSCC, melatonin induces intracellular ROS, whose accumulation plays an upstream role in mitochondria-mediated apoptosis and autophagy. Our findings indicate that melatonin, at high concentrations, combined with cisplatin and radiotherapy to improve its effectiveness, is a potential adjuvant agent.

Predicting Tumor Sensitivity to Chemotherapeutic Drugs in Oral Squamous Cell Carcinoma Patients

Oral Squamous Cell Carcinoma (OSCC) patients respond poorly to chemotherapy. We analyzed the expression of 11 drug response-related genes in 31 OSCC biopsies, collected prior to any treatment, using custom-designed PCR array. Further, we investigated the drug response pattern of selected anticancer drugs by BH3 (Bcl2 Homology-3) profiling in the primary cells isolated from OSCC tissues. Then, we correlated the results of drug-response gene expression pattern with apoptotic priming to predict tumor response to chemotherapy. The best performing drug (BPD) and response differences (RD) between the drugs were identified using statistical methods to select the best choice of drug in a personalized manner. Based on the correlation, we classified OSCC tumors as sensitive (13 tumors), moderately responsive (16 tumors) or resistant (2 tumors) to chemotherapy. We found that up-regulation of genes linked with drug resistance facilitates survival of tumor samples, which was revealed by the percentage of apoptotic priming. Moreover, we found that paclitaxel-induced 40–45% apoptotic priming compared to other drugs. Average response difference (RD) analysis showed that 80% of tumors responded well to paclitaxel as compared to other drugs studied. Therefore, gene expression analysis with BH3 profiling reveals drug sensitivity that could be translated for drug selection before treatment.

Patritumab with Cetuximab plus Platinum-Containing Therapy in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck: An Open-Label, Phase Ib Study

PURPOSE

Patritumab plus cetuximab with platinum as first-line therapy for patients with recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) was evaluated for safety and to determine the recommended phase II combination dose.

PATIENTS AND METHODS

Patients aged ≥18 years with confirmed R/M SCCHN received intravenous patritumab (18 mg/kg loading dose; 9 mg/kg maintenance dose every 3 weeks) + cetuximab (400 mg/m² loading dose; 250 mg/m² maintenance dose weekly) + cisplatin (100 mg/m² every 3 weeks) or carboplatin (AUC of 5) for six cycles or until toxicity, disease progression, or withdrawal. Primary endpoints were dose-limiting toxicities [DLT; grade ≥3 (21-day observation period)] and treatment-emergent adverse events (TEAE). Pharmacokinetics, human antihuman antibodies (HAHA), tumor response, progression-free survival (PFS), and overall survival (OS) were assessed.

RESULTS

Fifteen patients completed a median (range) of 8.7 (2.0-20.7) patritumab cycles. No DLTs were reported. Serious adverse events were reported in 9 patients (patritumab-related n = 4). TEAEs (N = 15 patients) led to patritumab interruption in 7 patients. Patritumab-related dose reductions were reported in 1 patient. Patritumab (18 mg/kg) pharmacokinetics (N = 15) showed mean (SD) AUC_0-21d of 2,619 (560) μg/day/mL and maximum concentration of 499.9 (90.4) μg/mL. All patients were HAHA-negative at study end (single, transient low titer in 1 patient). Tumor response rate (complete plus partial response; N = 15) was 47%. Median (95% confidence interval) PFS and OS (N = 15) were 7.9 (3.7-9.7) and 13.5 (6.6-17.5) months, respectively.

CONCLUSIONS

Patritumab (18 mg/kg loading dose, 9 mg/kg maintenance dose) plus cetuximab/platinum was tolerable, active in SCCHN, and selected as the phase II dose regimen.

Development of monoclonal anti-PDGF-CC antibodies as tools for investigating human tissue expression and for blocking PDGF-CC induced PDGFRα signalling in vivo

PDGF-CC is a member of the platelet-derived growth factor (PDGF) family that stimulates PDGFRα phosphorylation and thereby activates intracellular signalling events essential for development but also in cancer, fibrosis and neuropathologies involving blood-brain barrier (BBB) disruption. In order to elucidate the biological and pathological role(s) of PDGF-CC signalling, we have generated high affinity neutralizing monoclonal antibodies (mAbs) recognizing human PDGF-CC. We determined the complementarity determining regions (CDRs) of the selected clones, and mapped the binding epitope for clone 6B3. Using the monoclonal 6B3, we determined the expression pattern for PDGF-CC in different human primary tumours and control tissues, and explored its ability to neutralize PDGF-CC-induced phosphorylation of PDGFRα. In addition, we showed that PDGF-CC induced disruption of the blood-retinal barrier (BRB) was significantly reduced upon intraperitoneal administration of a chimeric anti-PDGF-CC antibody. In summary, we report on high affinity monoclonal antibodies against PDGF-CC that have therapeutic efficacy in vivo.

Preclinical toxicological assessment of a novel monoclonal antibody targeting human platelet-derived growth factor CC (PDGF-CC) in PDGF-CChum mice

Platelet-derived growth factor CC (PDGF-CC) is important during foetal development but also in pathogenesis of neurologic diseases, cancer and fibrosis. We have previously demonstrated that blocking the PDGF-CC/PDGF receptor alpha (PDGFRα) axis resulted in reduction of stroke volume and cerebrovascular permeability after experimentally induced stroke. Recently, we could translate these findings into the clinic showing that imatinib, a small tyrosine kinase inhibitor targeting PDGF receptors, can significantly improve neurological outcome after ischemic stroke in human. Herein we report preclinical toxicological analyses of our newly generated monoclonal anti-human PDGF-CC antibody 6B3 (mAb 6B3) in PDGF-CC humanized mice. Beside histological organ assessment, we also analysed serum, urine, haematological parameters and the general health status of the treated mice. We could not find any indications that mAb 6B3 is toxic or has other significant side effects neither in short, nor in long treatment regimens. Our results indicate that mAb 6B3 can be further developed for clinical use. This opens up the possibility to assess the therapeutic potential of blocking PDGF-CC in diverse pathological conditions such as neurologic diseases, cancer and fibrosis.

Investigation of ovatodiolide, a macrocyclic diterpenoid, as a potential inhibitor of oral cancer stem-like cells properties via the inhibition of the JAK2/STAT3/JARID1B signal circuit

BACKGROUND

The cancer stem cells (CSCs) have been shown to play key roles in the oral cancer initiation, distant metastasis, the development of chemoresistance and recurrence after treatment. Therefore, the inhibition of oral CSCs has been the target for therapeutic development.

PURPOSE

In this study, we investigated the anti-CSCs potential of Ovatodiolide (Ova), a diterpenoid isolate of Anisomeles indica, in vitro and in vivo.

METHODS

Oral CSCs were treated with Ova, and the expression of pluripotency factors Oct4, Sox-2, and Nanog were evaluated by western blot. Effect of Ova on self-renewal capacity and clonogenicity were assessed with the sphere formation and clonogenic assay in CSCs model derived from oral cancer cell. The effect of Ova was also investigated in a mouse xenograft model obtained by injecting nude mice with oral CSCs cells.

RESULTS

We demonstrated that Ova significantly and dose-dependently suppressed oral cancer cell viability and colony formation; Ova markedly inhibited the ALDH1 activities and reduced the CD44^high/ALDH^rich cell sub-population. Additionally, Ova suppressed orosphere formation by down-regulating CD133, Klf4, Oct4A, Nanog and JARID1B expression. Furthermore, Ova-mediated anti-cancer effects were associated with the dose-dependent reduction in the expression levels of STAT3, p-STAT3, pJAK2, pAKT and pERK1/2 protein. Moreover, Ova synergistically enhanced the anticancer effect of cisplatin against the SAS, FaDu, HSC-3 and TW2.6 orospheres. Ova significantly attenuated the tumor-initiating potential of orosphere in mouse xegnograft model.

CONCLUSION

These results demonstrate that Ova effectively suppressed oral tumorigenesis and stemness properties via JAK2/STAT3 signaling. Ova may be considered for future clinical usage.

Knockdown of Yin Yang 1 enhances anticancer effects of cisplatin through protein phosphatase 2A-mediated T308 dephosphorylation of AKT

Cisplatin is still one of the first-line drugs for chemotherapy of head and neck squamous cell carcinoma (HNSCC) and shows a survival advantage for HNSCC. However, a substantial proportion of HNSCC eventually becomes resistance to cisplatin and the underlying mechanisms remain to be fully understood. Yin Yang 1 (YY1) is a multifunctional protein regulating both gene transcription and protein modifications and also plays a role in chemotherapy resistance. Here, we reported that knockdown of YY1 by lentivirus-mediated short hairpin RNA or tetracycline-inducible short hairpin RNA enhanced cisplatin-induced apoptosis and inhibition of cell proliferation, migration and invasion in the HNSCC cell lines, and inhibition of the xenograft tumor growth. The underlying mechanisms were revealed that knockdown of YY1 downregulated both S473 and T308 phosphorylation of AKT (protein kinase B), which was mainly responsible for cisplatin resistance, whereas overexpression of YY1 upregulated both S473 and T308 phosphorylation. Cisplatin upregulated YY1 mRNA and protein expression and both S473 and T308 phosphorylation of AKT. In the presence of cisplatin, knockdown of YY1 not only blocked cisplatin-induced increase in S473 and T308 phosphorylation of AKT, but still downregulated T308 phosphorylation. Moreover, protein phosphatase 2A (PP2A) antagonist, okadaic acid, upregulated T308, but not S473, phosphorylation, and simultaneously abolished YY1 knockdown-mediated enhancement of cisplatin-induced inhibition of cell proliferation. In addition, knockdown of YY1 promoted PP2A activity through upregulating mRNA and protein expressions of PP2A catalytic subunit alpha (PPP2CA) through the binding of YY1 in the promoter of PPP2CA. Conversely, activating PP2A by forskolin also promoted YY1 degradation and subsequently inhibited T308 phosphorylation. These results suggested that knockdown of YY1 enhanced anticancer effects of cisplatin through PP2A mediating T308 dephosphorylation of AKT, and that targeting YY1 or PP2A would enhance the efficiency of cisplatin chemotherapy in treatment of HNSCC.

Diacylglycerol lipase alpha promotes tumorigenesis in oral cancer by cell-cycle progression

Diacylglycerol lipase alpha (DAGLA), which catalyzes the hydrolysis of diacylglycerol to 2-arachidonoylglycerol and free fatty acid, is required for axonal growth during the brain development and for retrograde synaptic signaling at mature synapses. So far, no information was found regarding the possible role of DAGLA in human tumorigenesis. Thus, the current study sought to clarify the contribution of DAGLA in oral squamous cell carcinomas (OSCCs) and assess the clinical possibilities for OSCC treatment. Using real-time quantitative reverse transcription-polymerase chain reaction, immunoblotting, and immunohistochemistry, we found a significant up-regulation of DAGLA in OSCCs compared with normal cells and tissues both at mRNA and protein expression levels. Knockdown models in OSCC-derived cell lines for DAGLA (siDAGLA) and treatment with a lipase inhibitor (orlistat) showed several depressed cellular functions, including cellular proliferation and migratory activities through cell-cycle arrest at G1 phase. Furthermore, we found that DAGLA-positive OSCC samples were correlated highly with the primary tumoral size. We concluded that DAGLA may be a key determinant in tumoral progression and might be a therapeutic target for OSCCs.

Autoregulation of RANK ligand in oral squamous cell carcinoma tumor cells

Oral squamous cell carcinoma (OSCC) is the most common malignancy among oral cancers and shows potent activity for local bone invasion. Receptor activator of nuclear factor κB (RANK) ligand (RANKL) is critical for bone-resorbing osteoclast formation. We previously demonstrated that OSCC tumor cells express high levels of RANKL. In this study, confocal microscopy demonstrated RANKL specific receptor, RANK expression in OSCC tumor cell lines (SCC1, SCC12, and SCC14a). We also confirmed the expression of RANK and RANKL in primary human OSCC tumor specimens. However, regulatory mechanisms of RANKL expression and a functional role in OSCC tumor progression are unclear. Interestingly, we identified that RANKL expression is autoregulated in OSCC tumor cells. The RANKL specific inhibitor osteoprotegerin (OPG) treatment to OSCC cells inhibits autoregulation of RANKL expression. Further, we showed conditioned media from RANKL CRISPR-Cas9 knockout OSCC cells significantly decreased osteoclast formation and bone resorption activity. In addition, RANKL increases OSCC tumor cell proliferation. RANKL treatment to OSCC cells demonstrated a dose-dependent increase in RANK intracellular adaptor protein, TRAF6 expression, and activation of IKK and IκB signaling molecules. We further identified that transcription factor NFATc2 mediates autoregulation of RANKL expression in OSCC cells. Thus, our results implicate RANKL autoregulation as a novel mechanism that facilitates OSCC tumor cell growth and osteoclast differentiation/bone destruction.

Genomic profiling is predictive of response to cisplatin treatment but not to PI3K inhibition in bladder cancer patient-derived xenografts

Purpose

Effective systemic therapeutic options are limited for bladder cancer. In this preclinical study we tested whether bladder cancer gene alterations may be predictive of treatment response.

Experimental design

We performed genomic profiling of two bladder cancer patient derived tumor xenografts (PDX). We optimized the exome sequence analysis method to overcome the mouse genome interference.

Results

We identified a number of somatic mutations, mostly shared by the primary tumors and PDX. In particular, BLCAb001, which is less responsive to cisplatin than BLCAb002, carried non-sense mutations in several genes associated with cisplatin resistance, including MLH1, BRCA2, and CASP8. Furthermore, RNA-Seq analysis revealed the overexpression of cisplatin resistance associated genes such as SLC7A11, TLE4, and IL1A in BLCAb001. Two different PIK3CA mutations, E542K and E545K, were identified in BLCAb001 and BLCAb002, respectively. Thus, we tested whether the genomic profiling was predictive of response to a dual PI3K/mTOR targeting agent, LY3023414. Despite harboring similar PIK3CA mutations, BLCAb001 and BLCAb002 exhibited differential response, both in vitro and in vivo. Sustained target modulation was observed in the sensitive model BLCAb002 but not in BLCAb001, as well as decreased autophagy. Interestingly, computational modelling of mutant structures and affinity binding to PI3K revealed that E542K mutation was associated with weaker drug binding than E545K.

Conclusions

Our results suggest that the presence of activating PIK3CA mutations may not necessarily predict in vivo treatment response to PI3K targeted therapies, while specific gene alterations may be predictive for cisplatin response in bladder cancer models and, potentially, in patients as well.

Metastatic model of HPV+ oropharyngeal squamous cell carcinoma demonstrates heterogeneity in tumor metastasis

Human papillomavirus induced (HPV+) cancer incidence is rapidly rising, comprising 60–80% of oropharyngeal squamous cell carcinomas (OPSCCs); while rare, recurrent/metastatic disease accounts for nearly all related deaths. An in vivo pre-clinical model for these invasive cancers is necessary for testing new therapies. We characterize an immune competent recurrent/metastatic HPV+ murine model of OPSSC which consists of four lung metastatic (MLM) cell lines isolated from an animal with HPV+ OPSCC that failed cisplatin/radiation treatment. These individual metastatic clonal cell lines were tested to verify their origin (parental transgene expression and define their physiological properties: proliferation, metastatic potential, heterogeneity and sensitivity/resistance to cisplatin and radiation. All MLMs retain expression of parental HPV16 E6 and E7 and degrade P53 yet are heterogeneous from one another and from the parental cell line as defined by Illumina expression microarray. Consistent with this, reverse phase protein array defines differences in protein expression/activation between MLMs as well as the parental line. While in vitro growth rates of MLMs are slower than the parental line, in vivo growth of MLM clones is greatly enhanced. Moreover, in vivo resistance to standard therapies is dramatically increased in 3 of the 4 MLMs. Lymphatic and/or lung metastasis occurs 100% of the time in one MLM line. This recurrent/metastatic model of HPV+ OPSCC retains the characteristics evident in refractory human disease (heterogeneity, resistance to therapy, metastasis in lymph nodes/lungs) thus serving as an ideal translational system to test novel therapeutics. Moreover, this system may provide insights into the molecular mechanisms of metastasis.

Role of β-catenin in cisplatin resistance, relapse and prognosis of head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is one of the most common types of cancer in India with high incidence and rapid recurrence rates. Here, we aimed to investigate the role of β-catenin, a developmental pathway gene, in HNSCC therapy resistance, DNA damage response, recurrence and prognosis.

METHODS

In total 80 HNSCC samples were included. Western blot, immunohistochemistry and qRT-PCR analyses were performed to assess β-catenin expression in the cut margin and tumor areas of each sample. Kaplan-Meier analyses were performed to correlate β-catenin expression with the survival and prognosis of HNSCC patients. In addition, chemo-resistance, DNA damage response and DNA repair capacities were evaluated in HNSCC-derived cell lines through LiCl-mediated up-regulation and siRNA-mediated silencing of β-catenin expression.

RESULTS

We observed β-catenin up-regulation in cut margin areas of recurrent patients compared to their corresponding tumor regions, which subsequently could be associated with poor prognosis. In addition, we found that LiCl-mediated up-regulation of β-catenin in HNSCC-derived cells led to cisplatin resistance, evasion of apoptosis, enhanced DNA repair and enhanced migration. The effects of β-catenin silencing correlated with its putative role in chemo-resistance and DNA damage response.

CONCLUSION

From our results we conclude that β-catenin may contribute to HNSCC therapy resistance and disease relapse. As such, β-catenin may be explored as a therapeutic target along with conventional therapeutics.

A comprehensive review of heregulins, HER3, and HER4 as potential therapeutic targets in cancer

Heregulins (HRGs) bind to the receptors HER3 or HER4, induce receptor dimerization, and trigger downstream signaling that leads to tumor progression and resistance to targeted therapies. Increased expression of HRGs has been associated with worse clinical prognosis; therefore, attempts to block HRG-dependent tumor growth have been pursued. This manuscript summarizes the function and signaling of HRGs and review the preclinical evidence of its involvement in carcinogenesis, prognosis, and treatment resistance in several malignancies such as colorectal cancer, non-small cell lung cancer, ovarian cancer, and breast cancer. Agents in preclinical development and clinical trials of novel therapeutics targeting HRG-dependent signaling are also discussed, including anti-HER3 and -HER4 antibodies, anti-metalloproteinase agents, and HRG fusion proteins. Although several trials have indicated an acceptable safety profile, translating preclinical findings into clinical practice remains a challenge in this field, possibly due to the complexity of downstream signaling and patterns of HRG, HER3 and HER4 expression in different cancer subtypes. Improving patient selection through biomarkers and understanding the resistance mechanisms may translate into significant clinical benefits in the near future.

The significance of lumican expression in ovarian cancer drug-resistant cell lines

PURPOSE

The aim of the present study is to determine the expression of LUM in drug-resistant ovarian cancer cell lines.

METHODS

Doxorubicin- (DOX), topotecan- (TOP) and vincristine- (VIN) resistant variants of the W1 ovarian cancer cell line were used in this study. We used quantitative real-time polymerase chain reactions to determine LUM mRNA levels. Protein expression was detected using Western blot and immunocytochemistry assays. Protein glycosylation was investigated using PGNase F digestion. Immunohistochemistry assays were used to determine protein expression in ovarian cancer patients.

RESULTS

We observed increased expression of LUM in drug-resistant cell lines at both the mRNA and the protein level. The most abundant LUM expression was observed in TOP-resistant cell line. We observed LUM bands that corresponded to different molecular masses, and the most abundant LUM form was the secreted form, which had a mass of 50 kDa. Double immunofluorescence analysis showed co-expression of LUM and COL3A1 as well as the presence of extracellular COL3A1 in the TOP-resistant cell line. Finally, we detected the LUM protein in ovarian cancer tissue.

CONCLUSION

The expression of LUM in cytostatic-resistant cell lines suggests its role in drug resistance. The co-expression of LUM and COL3A1 indicates the significance of LUM in collagen fibre assembly. Expression in ovarian cancer tissue suggests that LUM can play a role in ovarian cancer pathogenesis in ways similar to other cancers.

Expression of small leucine-rich extracellular matrix proteoglycans biglycan and lumican reveals oral lichen planus malignant potential

OBJECTIVES

The aim of this study was to examine molecular alterations on the protein level in lesions of oral lichen planus (OLP), oral squamous cell carcinoma (OSCC) and healthy mucosa.

MATERIALS AND METHODS

Global protein profiling methods based on liquid chromatography coupled to mass spectrometry (LC-MS) were used, with a special emphasis on evaluation of deregulated extracellular matrix molecules expression, as well as on analyses of IG2F and IGFR2 expression in healthy mucosa, OLP and OSCC tissues by comparative semi-quantitative immunohistochemistry.

RESULTS

Mass spectrometry-based proteomics profiling of healthy mucosa, OLP and OSCC tissues (and accompanied histologically unaltered tissues, respectively) identified 55 extracellular matrix proteins. Twenty among identified proteins were common to all groups of samples. Expression of small leucine-rich extracellular matrix proteoglycans lumican and biglycan was found both in OSCC and OLP and they were validated by Western blot analysis as putative biomarkers. A significant increase (p < 0.05) of biglycan expression in OLP-AT group was determined in comparison with OLP-T group, while lumican showed significant up-regulation (p < 0.05) in OLP-T and OSCC-T groups vs. adjacent and control tissue groups. Biglycan expression was only determined in OSCC-AT group. Immunohistochemical analysis of IGF2 and IG2FR expression revealed no significant difference among groups of samples.

CONCLUSION/CLINICAL RELEVANCE

Biglycan and lumican were identified as important pathogenesis biomarkers of OLP that point to its malignant potential.

Epigallocatechin gallate sensitizes cisplatin-resistant oral cancer CAR cell apoptosis and autophagy through stimulating AKT/STAT3 pathway and suppressing multidrug resistance 1 signaling

Epigallocatechin gallate (EGCG) is a green tea polyphenol that presents anticancer activities in multiple cancer cells, but no available report was addressed for the underling molecular mechanism of cytotoxic impacts on drug-resistant oral squamous cell carcinoma cells. In the present study, the inhibitory effects of EGCG were experienced on cisplatin-resistant oral cancer CAR cells. EGCG inhibited cell viability in a time- and concentration-dependent manner by a sulforhodamine B (SRB) assay. EGCG induced CAR cell apoptosis and autophagy by 4',6-diamidino-2-phenylindole (DAPI) dye, acridine orange (AO) staining and green fluorescent protein (GFP)-tagged LC3B assay, respectively. EGCG also significantly enhanced caspase-9 and caspase-3 activities by caspase activity assay. EGCG markedly increased the protein levels of Bax, cleaved caspase-9, cleaved caspase-3, Atg5, Atg7, Atg12, Beclin-1, and LC3B-II, as well as significantly decreased the expression of Bcl-2, phosphorylated AKT (Ser473) and phosphorylation of STAT3 on Tyr705 by western blotting in CAR cells. Importantly, the protein and gene expression of multidrug resistance 1 (MDR1) were dose-dependently inhibited by EGCG. Overall, downregulation of MDR1 levels and alterations of AKT/STAT3 signaling contributed to EGCG-induced apoptosis and autophagy in CAR cells. Based on these results, EGCG has the potential for therapeutic effect on oral cancer and may be useful for long-term oral cancer prevention in the future. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 845-855, 2017.

TCRP1 expression is associated with platinum sensitivity in human lung and ovarian cancer cells

Platinum-based drugs, including cisplatin (DDP) and oxaliplatin (L-OHP), are among the most potent chemotherapy drugs, and are widely utilized for the treatment of human lung and ovarian cancer. However, certain patients do not respond to platinum-based agents, and even those who initially benefit from the treatment will eventually exhibit resistance to these drugs. Although certain factors have been investigated for their potential to predict platinum resistance, more effective predictors for the improved management of patients with lung and ovarian cancer are required. Tongue cancer resistance-associated protein 1 (TCRP1) is a newly identified gene, which was cloned from a multi-drug resistant cell line of tongue cancer. Previous data has shown that TCRP1 is able to mediate DDP resistance in human oral squamous cell carcinoma cells. However, the contribution of TCRP1 to the resistance of platinum agents in human lung and ovarian cancer cells remains to be elucidated. Our previous study showed that TCRP1 expression levels in samples of lung and ovarian cancer were significantly increased compared with normal controls. In the present study, it was demonstrated that TCRP1 contributed to the resistance to DDP and L-OHP in human lung and ovarian cancer cells. Knockdown of TCRP1 resensitized the cells to the platinum-based agents. The present study identified a positive correlation between TCRP1 expression and primary resistance to DDP and L-OHP in lung cancer cells. In addition, it was observed that cells treated with nuclear factor (NF)-κB inhibitor BAY 11-7082 displayed increased sensitivity to DDP and L-OHP. The results of the present study suggested that TCRP1 may be associated with resistance to DDP and L-OHP in lung and ovarian cancer cells, and the Akt/NF-κB signaling pathway may be involved in the functioning of TCRP1. These findings identify TCRP1 as a potential predictor of platinum resistance in the treatment of lung and ovarian cancer.

Transforming growth factor β1 enhances stemness of head and neck squamous cell carcinoma cells through activation of Wnt signaling

Transforming growth factor β (TGFβ) ligands, including TGFβ1, are multifunctional cytokines known as key regulators of cell growth, differentiation and inflammation. Dysregulated TGFβ signaling is common in numerous solid tumors, including head and neck squamous cell carcinoma (HNSCC). Previously, TGFβ ligands were also reported to be associated with an enhancement of stemness in glioma stem-like cells. However, their role in HNSCC cancer stem cells (CSCs) has not been explored. The present study demonstrated that TGFβ1 enriches the properties of HNSCC CSCs. TGFβ1 promoted sphere formation and increased stemness-associated gene expression (Oct4 and Sox2) of primary HNSCC CSCs. Additionally, the population of aldehyde dehydrogenase (ALDH)-positive cells was increased subsequent to exogenous treatment of cells with TGFβ1. In addition, following stimulation with TGFβ1, the cells exhibited more resistance to cisplatin and elevated expression of Twist, Snail and Slug. Mechanistically, TGFβ1 acts as an upstream stimulator of Wnt/β-catenin signaling. Collectively, the present findings provide insights toward the development of TGFβ1 signaling inhibition strategies for treating HNSCC CSCs.

Inhibition of HDAC6 Protein Enhances Bortezomib-induced Apoptosis in Head and Neck Squamous Cell Carcinoma (HNSCC) by Reducing Autophagy

Chemoresistance is a major barrier to effective chemotherapy of solid tumors, including head and neck squamous cell carcinoma (HNSCC). Recently, autophagy, a highly conservative intracellular recycling system, has shown to be associated with chemoresistance in cancer cells. However, little is known about how autophagy plays a role in the development of chemoresistance in HNSCC and how autophagy is initiated when HNSCC cells undergo cytotoxic stress. Here, we report that autophagy was activated when HNSCC cells are treated with the proteasome inhibitor bortezomib, proposed as an alternative chemotherapeutic agent for both primary and cisplatin-resistant HNSCC cells. Ablation of histone deacetylase 6 (HDAC6) expression and its activity in HNSCC cells significantly inhibited autophagy induction by altering the phosphorylation status of mammalian target of rapamycin and enhanced the bortezomib cytotoxicity. Similarly, a combination regimen of bortezomib and the histone deacetylase inhibitor trichostatin A abolished HDAC6 activity and decreased autophagy induction while significantly enhancing bortezomib-induced apoptosis in HNSCC cells. These data uncover a novel molecular mechanism indicating that HDAC6 may serve as a critical causal link between autophagy, apoptosis, and the cell survival response in HNSCC. A combination regimen resulting in regression of autophagy improves chemotherapeutic efficacy, thereby providing a new strategy to overcome chemoresistance and to improve the treatment and survival of HNSCC patients.

Carboxyl-Terminal Modulator Protein Positively Acts as an Oncogenic Driver in Head and Neck Squamous Cell Carcinoma via Regulating Akt phosphorylation

The exact regulatory mechanisms of carboxyl-terminal modulator protein (CTMP) and its downstream pathways in cancer have been controversial and are not completely understood. Here, we report a new mechanism of regulation of Akt serine/threonine kinase, one of the most important dysregulated signals in head and neck squamous cell carcinoma (HNSCC) by the CTMP pathway and its clinical implications. We find that HNSCC tumor tissues and cell lines had relatively high levels of CTMP expression. Clinical data indicate that CTMP expression was significantly associated with positive lymph node metastasis (OR = 3.8, P = 0.033) and correlated with poor prognosis in patients with HNSCC. CTMP was also positively correlated with Akt/GSK-3β phosphorylation, Snail up-regulation and E-cadherin down-regulation, which lead to increased proliferation and epithelial-to-mesenchymal transition, suggesting that CTMP expression results in enhanced tumorigenic and metastatic properties of HNSCC cells. Moreover, CTMP suppression restores sensitivity to cisplatin chemotherapy. Intriguingly, all the molecular responses to CTMP regulation are identical regardless of p53 status in HNSCC cells. We conclude that CTMP promotes Akt phosphorylation and functions as an oncogenic driver and prognostic marker in HNSCC irrespective of p53.

Moving towards personalised therapy in head and neck squamous cell carcinoma through analysis of next generation sequencing data

Personalised medicine tumour boards, which leverage genomic data to improve clinical management, are becoming standard for the treatment of many cancers. This paper is designed as a primer to assist clinicians treating head and neck squamous cell carcinoma (HNSCC) patients with an understanding of the discovery and functional impact of recurrent genetic lesions that are likely to influence the management of this disease in the near future. This manuscript integrates genetic data from publicly available array comparative genome hybridization (aCGH) and next-generation sequencing genetics databases to identify the most common molecular alterations in HNSCC. The importance of these genetic discoveries is reviewed and how they may be incorporated into clinical care decisions is discussed. Considerations for the role of genetic stratification in the clinical management of head and neck cancer are maturing rapidly and can be improved by integrating data sets. This article is meant to summarise the discoveries made using multiple genomic platforms so that the head and neck cancer care provider can apply these discoveries to improve clinical care.

Growth inhibition and chemo-radiosensitization of head and neck squamous cell carcinoma (HNSCC) by survivin-siRNA lentivirus

BACKGROUND

Survivin expression is often associated with aggressive tumor behavior and therapy resistance. In this study, we investigated the effect of survivin knockdown by survivin-siRNA lentiviral vector (Svv-Lent) on the response of HNSCC to chemo-radiotherapy, tumor growth and metastasis.

METHODS

Four human HNSCC (OSC19, Cal27, Cal33 and FaDu) and one normal HOK cell lines were included in the study, and survivin knockdown was achieved with Svv-Lent treatment. Cell proliferation and apoptosis were measured by MTT and TUNEL assay, respectively. Transwell assays were performed to measure in vitro cell migration and matrigel invasion. Xenograft tumors were developed in nude mice by injecting Cal27 cells subcutaneously and following tail-vein injection of lung and liver metastasis.

RESULTS

Knockdown of survivin significantly suppressed HNSCC cell proliferation and induced apoptosis in vitro. Survivin inhibition could also significantly reduce in vitro cell migration and matrigel invasion that might be due to inactivation of matrix metalloproteinases. In vivo studies showed significant repression of Cal27 xenograft tumor growth and tissue metastasis leading to improvement in mice survival in the Svv-Lent treated group compared to controls. Our data indicated that survivin expression in HNSCC cells contributed to chemo-radioresistance, and its down-regulation increased anti-cancer effects of paclitaxel, cisplatin and radiation.

CONCLUSIONS

Our findings suggest that sustained survivin expression facilitates HNSCC tumor growth and confers resistance to chemo-radiotherapy. Svv-Lent therapy may be able to enhance the cytotoxic effect of commonly used anticancer drugs such as cisplatin and paclitaxel, and radiotherapy that could provide a promising strategy for the effective control of resistant head and neck cancer.