Positive association of glucose-regulated protein 78 during oral cancer progression and the prognostic value in oral precancerous lesions

EIF3D promoted cervical carcinoma through Warburg effect by interacting with GRP78

The incidence of cervical cancer ranks third among all female tumours globally and second in developing countries. However, the role of eukaryotic translation initiation factor 3 subunit D (EIF3D) in cervical carcinoma is unknown. This study investigated the effects of EIF3D on cell progression of cervical carcinoma and its underlying mechanism in vivo and vitro models. There were increases of EIF3D expression mRNA and protein expression levels in patients with cervical carcinoma. Disease-free survival (DFS) and overall surviva (OS) of EIF3D lower expression in patients with cervical carcinoma was higher than those of EIF3D higher expression. EIF3D mRNA expression levels in cervical carcinoma cell lines (AV3, Hela229, CaSki and Hela cells) were up-regulated, compared with cervical normal cell line (UVECs). EIF3D promoted cell growth and Warburg effect in vitro model of cervical carcinoma. EIF3D interacting with GRP78 to reduce the activity of GRP78 in vitro model of cervical carcinoma. The inhibition of GRP78 reduced the effects of EIF3D on Warburg effect in vitro model of cervical carcinoma.Our work identifies EIF3D promoted cell growth and Warburg effect in vitro model of cervical carcinoma and the inhibition of EIF3D represents a potential therapeutic strategy for the treatment of cervical carcinoma.IMPACT STATEMENTWhat is already known on this subject? The incidence of cervical cancer ranks third among all female tumours globally and second in developing countries.What do the results of this study add? This study investigated the effects of EIF3D on cell progression of cervical carcinoma and its underlying mechanism in vivo and vitro models.What are the implications of these findings for clinical practice and/or further research? EIF3D promoted cell growth and Warburg effect in vitro model of cervical carcinoma and the inhibition of EIF3D represents a potential therapeutic strategy for the treatment of cervical carcinoma.

Expression of GRP78 and its copartners in HEK293 and pancreatic cancer cell lines (BxPC-3/PANC-1) exposed to MRI and CT contrast agents

Endoplasmic reticulum (ER) stress-associated chaperones trigger a defense mechanism called as unfolded protein response (UPR) which can manage apoptosis and be determinative in cell fate. Both anticancer drug effects and potential toxicity effects of magnetic resonance imaging (MRI) and computed tomography (CT) contrast agents were aimed to be evaluated. For this purpose, we investigated expression profiles of endoplasmic reticulum stress-associated chaperone molecules in human pancreatic tumor lines BxPC-3 and PANC-1 and control human embryonic kidney cells 293 (HEK293) induced with a variety of gadolinium and iohexol contrast agents. Protein expression levels of ER stress-associated chaperones (master regulator: GRP78/Bip and its copartners: Calnexin, Ero1, PDI, CHOP, IRE1α and PERK) were evaluated with Western blotting. Expression levels at mRNA level were also assessed for GRP78/Bip and CHOP with real-time PCR. Induction of cells was carried out with four different Gd-based contrast agents (GBCAs): (Dotarem, Optimark, Primovist and Gadovist) and two different iohexol agents (Omnipol, Omnipaque). CT contrast agents tested in the study did not result in significant ER stress in HEK293 cells. However, they do not seem to have theranostic potential in pancreas cancer through ER pathway. The potential efficiency of macrocyclic MRI contrast agents to provoke apoptosis via ER stress-associated chaperones in BxPC-3 cells lends credibility for their future theranostic use in pancreas cancer as long as undesired toxicity effects were carefully considered. ER stress markers and/or contrast agents seem to have promising potential to be translated into the clinical practice to manage pancreas cancer progression.

Unveiling the dark side of glucose-regulated protein 78 (GRP78) in cancers and other human pathology: a systematic review

Glucose-Regulated Protein 78 (GRP78) is a chaperone protein that is predominantly expressed in the lumen of the endoplasmic reticulum. GRP78 plays a crucial role in protein folding by assisting in the assembly of misfolded proteins. Under cellular stress conditions, GRP78 can translocate to the cell surface (csGRP78) were it interacts with different ligands to initiate various intracellular pathways. The expression of csGRP78 has been associated with tumor initiation and progression of multiple cancer types. This review provides a comprehensive analysis of the existing evidence on the roles of GRP78 in various types of cancer and other human pathology. Additionally, the review discusses the current understanding of the mechanisms underlying GRP78's involvement in tumorigenesis and cancer advancement. Furthermore, we highlight recent innovative approaches employed in downregulating GRP78 expression in cancers as a potential therapeutic target.

Biomarkers of malignant transformation in oral leukoplakia: from bench to bedside

Oral leukoplakia is a common precursor lesion of oral squamous cell carcinoma, which indicates a high potential of malignancy. The malignant transformation of oral leukoplakia seriously affects patient survival and quality of life; however, it is difficult to identify oral leukoplakia patients who will develop carcinoma because no biomarker exists to predict malignant transformation for effective clinical management. As a major problem in the field of head and neck pathologies, it is imperative to identify biomarkers of malignant transformation in oral leukoplakia. In this review, we discuss the potential biomarkers of malignant transformation reported in the literature and explore the translational probabilities from bench to bedside. Although no single biomarker has yet been applied in the clinical setting, profiling for genomic instability might be a promising adjunct.

Is GRP78 (Glucose-regulated protein 78) a prognostic biomarker in differents types of cancer? A systematic review and meta-analysis

GRP78 is a chaperone with anti-apoptotic function associated with aggressive tumors. This systematic review aimed to evaluate GRP78 expression in cancer and its relation to prognosis outcomes. This review was conducted in different databases searching for human cancer studies assessing GRP78 immunohistochemical levels on tissue samples. A total of 98 manuscripts were included. In 62% of the studies, GRP78 was associated with a worse prognosis. A meta-analysis included 29 studies that detected a significantly higher expression of GRP78 in cancer tissues (RR= 2.35, 95% CI 1.75-3.15) compared to control. A meta-analysis of 3 and 5-years Overall Survival revealed an increased risk of death for tumors with high expression of GRP78 (RR=1.36, 95%CI 1.16-1,59, I² = 57%) and (RR=1.65, 95%CI 1.22-2.21, I² =64%), respectively. GRP78 is an important prognostic biomarker for different types of cancer and a promising therapeutic target.

Potential to Eradicate Cancer Stemness by Targeting Cell Surface GRP78

Cancer stemness is proposed to be the main cause of metastasis and tumor relapse after conventional therapy due to the main properties of cancer stem cells. These include unlimited self-renewal, the low percentage in a cell population, asymmetric/symmetric cell division, and the hypothetical different nature for absorbing external substances. As the mechanism of how cancer stemness is maintained remains unknown, further investigation into the basic features of cancer stemness is required. Many articles demonstrated that glucose-regulated protein 78 (GRP78) plays a key role in cancer stemness, suggesting that this molecule is feasible for targeting cancer stem cells. This review summarizes the history of finding cancer stem cells, as well as the functions of GRP78 in cancer stemness, for discussing the possibility of targeting GRP78 to eradicate cancer stemness.

Endoplasmic Reticulum Stress of Oral Squamous Cell Carcinoma Induces Immunosuppression of Neutrophils

The endoplasmic reticulum (ER) stress of cancer cells not only determined cancer cell fate but also indirectly triggered proinflammatory or immunosuppressive responses of macrophages. In addition, ER stressed neutrophils were known to acquire immunosuppressive activity with surface expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). Since the importance of tumor ER stress and immunosuppressive neutrophils has been emphasized in head and neck cancers, we hypothesized that the ER stress of oral squamous cell carcinoma (OSCC) could transform neutrophils into LOX-1 expressing immunosuppressive phenotype. Two human OSCC cell lines, SCC25 and OML1, were treated with either vehicle or thapsigargin (THG), an ER stress inducer. These tumor conditioned media (TCM) were collected accordingly. Then human peripheral blood neutrophils from healthy donors were cultured in these TCM. The results showed that neutrophils cultured in THG-treated TCM had higher expression of LOX-1 compared with those cultured in vehicle-treated TCM. Moreover, by interleukin-2/anti-CD3/anti-CD28 activated autologous T cell proliferation assay, neutrophils conditioned by THG-treated TCM were shown to inhibit T cell proliferation more significantly than those conditioned by vehicle-treated TCM. These novel findings indicated that the ER stress of OSCC could be transmitted to neutrophils which in turn expressed LOX-1 and obtained immunosuppressive ability. Our findings further supported the existence of "transmissible" ER stress between tumor cells and neutrophils.

YAP-Dependent BiP Induction Is Involved in Nicotine-Mediated Oral Cancer Malignancy

Cigarette smoking is a significant risk factor for the development and progression of oral cancer. Previous studies have reported an association between nicotine and malignancy in oral cancer. Recent studies have also demonstrated that nicotine can induce endoplasmic reticulum (ER) stress in tumor cells. Binding immunoglobulin protein (BiP) acts as a master regulator of ER stress and is frequently overexpressed in oral cancer cell lines and tissues. However, the effect of nicotine on BiP in oral cancer is unknown. Therefore, this study aimed to evaluate the role of BiP and its underlying regulatory mechanisms in nicotine-induced oral cancer progression. Our results showed that nicotine significantly induced the expression of BiP in time- and dose-dependent manners in oral squamous cell carcinoma (OSCC) cells. In addition, BiP was involved in nicotine-mediated OSCC malignancy, and depletion of BiP expression remarkably suppressed nicotine-induced malignant behaviors, including epithelial-mesenchymal transition (EMT) change, migration, and invasion. In vivo, BiP silencing abrogated nicotine-induced tumor growth and EMT switch in nude mice. Moreover, nicotine stimulated BiP expression through the activation of the YAP-TEAD transcriptional complex. Mechanistically, we observed that nicotine regulated YAP nuclear translocation and its interaction with TEAD through α7-nAChR-Akt signaling, subsequently resulting in increased TEAD occupancy on the HSPA5 promoter and elevated promoter activity. These observations suggest that BiP is involved in nicotine-induced oral cancer malignancy and may have therapeutic potential in tobacco-related oral cancer.

Oral potentially malignant disorders: A scoping review of prognostic biomarkers

This scoping review aimed to map evidence regarding biomarkers for malignant transformation of oral potentially malignant disorders (OPMD). Seventy-three longitudinal studies investigating prognostic biomarkers for OPMD malignant transformation were included, encompassing 5612 disorders and 108 biomarkers, of which 72 were investigated by immunohistochemistry. Most biomarkers were assessed in one or two studies, while five (p53, Ki-67, podoplanin, p16, and DNA ploidy) were analyzed in five or more studies. All studies investigating podoplanin (n = 8) reported a significant association between positive/high immunoexpression and malignant transformation. Similarly, all studies assessing DNA ploidy (n = 5) found that aneuploidy or gross genomic aberrations were significantly associated with malignant transformation. Included studies often presented mixed data from different OPMD subtypes, inadequate description of population characteristics, and lack of adjusted analysis for confounding factors. One hundred and eight biomarkers were identified and, from these, podoplanin immunoexpression and DNA ploidy were considered promising candidates for future long-term clinical research.

World Workshop on Oral Medicine VII: Prognostic biomarkers in oral leukoplakia: A systematic review of longitudinal studies

OBJECTIVE

To identify the prognostic biomarker candidates for stratification and long-term surveillance of oral leukoplakia progressing to cancer via a systematic literature review.

MATERIALS AND METHODS

Systematic searches with no date restrictions were conducted on March 29, 2018, targeting the databases PubMed (Ovid), EMBASE (Ovid), EBM (Ovid), and Web of Science (ISI). Bias was assessed using the Quality in Prognosis Studies tool. Biomarkers were stratified based on hallmarks of cancer.

RESULTS

Inclusion criteria were met by 25 of 3,415 studies. A range of biomarkers were evaluated experimentally for risk stratification, prognosis, and surveillance of oral leukoplakia in tissue, blood, and saliva. However, the studies were highly heterogeneous and require further validation. Biomarkers reported in these studies included inflammatory or oxidative markers, growth factors, ion channels, genetic and cellular regulatory factors, and epigenetic biomarkers. Studies tended to include small sample sizes, under-reported or variably reported histopathological data, did not address potential confounding, reported limited/variable follow-up data, or lacked a control group. Inclusion of subsets from chemoprevention trials may have introduced bias regarding reported malignant transformation rates and accuracy of prognostic biomarkers.

CONCLUSIONS

This review identified insufficient longitudinal evidence to support validated prognostic biomarkers for oral leukoplakia. Further studies are needed to identify molecular targets with the potential to mitigate risk of malignant transformation.

Multifaceted Mechanisms of Areca Nuts in Oral Carcinogenesis: the Molecular Pathology from Precancerous Condition to Malignant Transformation

Oral cancer is one of the most frequent malignant diseases worldwide, and areca nut is a primary carcinogen causing this cancer in Southeast Asia. It has been widely reported that areca nut induced several cytotoxic effects in oral cells, including ROS generation, inflammation, tissue hypoxia, DNA damage, and cell invasion. Recently, through chronic exposure model, more extensive pathological effects due to areca nut have been found. These include the induction of autophagy, promotion of epithelial- mesenchymal transition, and facilitation of cancer stemness conversion. Clinical findings support these adverse effects. Oral submucosal fibrosis, a premalignant condition, is prevalent in the area with habitual chewing of areca nuts. Consistently, oral cancer patients with habitual chewing areca nut exhibit more aggressive phenotypes, including resistance to chemo-radiotherapy. In this review, we comprehensively discuss and concisely summarize the up-to-date molecular and cellular mechanisms by which areca nuts contribute to malignant transformation. This review may provide critical information regarding clinical applications in risk assessment, disease prevention, diagnosis, and personalized therapeutics for areca nut-induced oral malignancy.

CEMIP upregulates BiP to promote breast cancer cell survival in hypoxia

Cell migration-inducing protein (CEMIP) and binding immunoglobulin protein (BiP) are upregulated in human cancers, where they drive cancer progression and metastasis. It has been shown that CEMIP resides in the endoplasmic reticulum (ER) where it interacts with BiP to induce cell migration, but the relationship between the two proteins was previously unknown. Here we show that CEMIP mediates activation of the BiP promoter and upregulates BiP transcript and protein levels in breast cancer cell lines. Moreover, CEMIP overexpression confers protective adaptations to cancer cells under hypoxic conditions, by decreasing apoptosis, activating autophagy, and increasing glucose uptake, to facilitate tumor growth. We demonstrate that BiP signals downstream of CEMIP, modulating cellular resistance to hypoxia. Reducing BiP in CEMIP-expressing cells sensitized cells to hypoxia treatment, decreased glucose uptake, and resulted in tumor regression in vivo. Our study provides insights into the link between CEMIP and BiP expression and the pro-survival role they play in hypoxia. Better understanding of the mechanisms behind cancer cell adaptations to harsh tumor environments could lead to development of improved cancer treatments.

Impact and Relevance of the Unfolded Protein Response in HNSCC

Head and neck squamous cell carcinomas (HNSCC) encompass a heterogeneous group of solid tumors that arise from the upper aerodigestive tract. The tumor cells face multiple challenges including an acute demand of protein synthesis often driven by oncogene activation, limited nutrient and oxygen supply and exposure to chemo/radiotherapy, which forces them to develop adaptive mechanisms such as the Unfolded Protein Response (UPR). It is now well documented that the UPR, a homeostatic mechanism, is induced at different stages of cancer progression in response to intrinsic (oncogenic activation) or extrinsic (microenvironment) perturbations. This review will discuss the role of the UPR in HNSCC as well as in the key processes that characterize the physiology of HNSCC. The role of the UPR in the clinical context of HNSCC will also be addressed.

Targeting the unfolded protein response in head and neck and oral cavity cancers

Many FDA-approved anti-cancer therapies, targeted toward a wide array of molecular targets and signaling networks, have been demonstrated to activate the unfolded protein response (UPR). Despite a critical role for UPR signaling in the apoptotic execution of cancer cells by many of these compounds, the authors are currently unaware of any instance whereby a cancer drug was developed with the UPR as the intended target. With the essential role of the UPR as a driving force in the genesis and maintenance of the malignant phenotype, a great number of pre-clinical studies have surged into the medical literature describing the ability of dozens of compounds to induce UPR signaling in a myriad of cancer models. The focus of the current work is to review the literature and explore the role of the UPR as a mediator of chemotherapy-induced cell death in squamous cell carcinomas of the head and neck (HNSCC) and oral cavity (OCSCC), with an emphasis on preclinical studies.

Prognostic role of BiP/GRP78 expression as ER stress in patients with gastric adenocarcinoma

PURPOSE

The glucose-regulated protein 78 (GRP78), also referred to as immunoglobulin heavy chain binding protein (BiP) (BiP/GRP78), is a major molecular chaperone in the endoplasmic reticulum (ER) and is extensively expressed in human neoplasms. Although the enhanced expression of BiP/GRP78 has been described to be associated with poor prognosis in gastric cancer (GC), details regarding its prognostic significance remain unclear. The aim of this study was to elucidate the prognostic role of BiP/GRP78 in patients with GC.

METHODS

Study subjects included 328 patients who underwent surgical resection. Tumor specimens of primary tumors underwent immunohistochemical staining for BiP/GRP78.

RESULTS

BiP/GRP78 was highly expressed in 57% (188/328) of patients. High expression of BiP/GRP78 was significantly associated with older age, male, disease staging, T factor, lymph node metastases, differentiation, lymphatic permeation, and vascular invasion. According to univariate analysis, age, disease staging, T factor, N factor, lymphatic permeation, vascular invasion, and BiP/GRP78 expression were significant prognostic factors for OS. In particular, high BiP/GRP78 expression was proven to be a significant predictor of prognosis in patients with older age, female sex, early disease stage, T1-2 factor, well or moderately differentiated tumors, and negative vascular invasion.

CONCLUSION

BiP/GRP78 is significantly associated with tumor aggressiveness and progression. The increased expression of BiP/GRP78 was identified as an independent factor for predicting poor OS in patients with early stage of disease, especially T1-2 factor.

Inhibition of GRP78 abrogates radioresistance in oropharyngeal carcinoma cells after EGFR inhibition by cetuximab

The EGFR-specific mAb cetuximab is one of the most effective treatments for oropharyngeal carcinoma, while patient responses to EGFR inhibitors given alone are modest. Combination treatment with radiation can improve the efficacy of treatment through increasing radiosensitivity, while resistance to radiation after administration of cetuximab limits its efficiency. Radiation and drugs can damage the endoplasmic reticulum (ER) homeostatic state and result in ER stress (ERS), subsequently causing resistance to radiation and drugs. Whether the ERS pathway is involved in radioresistance after administration of cetuximab has not been reported. Herein, we show that cetuximab could increase the radiosensitivity of FaDu cells but not Detroit562 cells. In addition, cetuximab inhibited the radiation-induced activation of the ERS signalling pathway IRE1α/ATF6-GRP78 in FaDu cells, while this effect was absent in Detroit562 cells. Silencing GRP78 increased the radiosensitivity of oropharyngeal carcinoma cells and inhibited radiation-induced DNA double-strand-break (DSB) repair and autophagy. More interestingly, silencing GRP78 abrogated resistance to cetuximab and radiation in Detroit562 cells and had a synergistic effect with cetuximab in increasing the radiosensitivity of FaDu cells. Immunohistochemistry showed that overexpression of both GRP78 and EGFR was associated with a poor prognosis in oropharyngeal carcinoma patients (P<0.05). Overall, the results of this study show that radioresistance after EGFR inhibition by cetuximab is mediated by the ERS signalling pathway IRE1α/ATF6-GRP78. This suppression was consequently unable to inhibit radiation-induced DSB repair and autophagy in oropharyngeal carcinoma cells, which conferred resistance to radiotherapy and cetuximab. These results suggest that the cooperative effects of radiotherapy and cetuximab could be further improved by inhibiting GRP78 in non-responsive oropharyngeal carcinoma patients.

GDF15 contributes to radioresistance and cancer stemness of head and neck cancer by regulating cellular reactive oxygen species via a SMAD-associated signaling pathway

Radiotherapy is an integral part for the treatment of head and neck cancer (HNC), while radioresistance is a major cause leads to treatment failure. GDF15, a member of the TGF-β superfamily, is hypothesized to participate in various types of homeostasis. However, the potential role of this molecule in regulation of radiosensitivity remains unclear. In this study, we demonstrated that GDF15 contributed to radioresistance of HNC, as determined by both gain- and lost-of-functional experiments. These results were achieved by the induction of mitochondrial membrane potential and suppression of intracellular reactive oxygen species (ROS). We further showed that GDF15 facilitated the conversion of cancer stemness, as assessed by the promotion of CD44+ and ALDH1+ cell populations and spheroid cell formation. At molecular level, GDF15 conferred to these cellular functions was through phosphorylated SMAD1 proteins to elite downstream signaling molecules. These cellular results were further confirmed in a tumor xenograft mouse study. Taken together, our results demonstrated that GDF15 contributed to radioresistance and cancer stemness by regulating cellular ROS levels via a SMAD-associated signaling pathway. GDF15 may serve as a prediction marker of radioresistance and a therapeutic target for the development of radio-sensitizing agents for the treatment of refractory HNC.

Borrelidin Induces the Unfolded Protein Response in Oral Cancer Cells and Chop-Dependent Apoptosis

Oral squamous cell carcinoma (OSCC) is the most common cancer affecting the oral cavity, and US clinics will register about 30,000 new patients in 2015. Current treatment modalities include chemotherapy, surgery, and radiotherapy, which often result in astonishing disfigurement. Cancers of the head and neck display enhanced levels of glucose-regulated proteins and translation initiation factors associated with endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). Previous work demonstrated that chemically enforced UPR could overwhelm these adaptive features and selectively kill malignant cells. The threonyl-tRNA synthetase (ThRS) inhibitor borrelidin and two congeners were discovered in a cell-based chemical genomic screen. Borrelidin increased XBP1 splicing and led to accumulation of phosphorylated eIF2α and UPR-associated genes, prior to death in panel of OSCC cells. Murine embryonic fibroblasts (MEFs) null for GCN2 and PERK were less able to accumulate UPR markers and were resistant to borrelidin. This study demonstrates that UPR induction is a feature of ThRS inhibition and adds to a growing body of literature suggesting ThRS inhibitors might selectively target cancer cells.

Expression of ER stress markers (GRP78/BiP and PERK) in adenoid cystic carcinoma

CONCLUSION

A high GRP78/BiP expression was proved to be a significant marker for predicting poor outcome after surgery. GRP78/BiP may be a promising molecular target for treatment of ACC.

BACKGROUND

The glucose-regulated protein GRP78/BiP plays a crucial role in the endoplasmic reticulum (ER) stress. The level of GRP78 is highly elevated in various human cancers, but the clinicopathological significance of GRP78/BiP remains controversial in patients with adenoid cystic carcinoma (ACC).

METHODS

A total of 26 ACC patients were analyzed, and tumor specimens were stained by immunohistochemistry for GRP78/BiP, PERK, Ki-67, and microvessel density (MVD) determined by CD34.

RESULTS

GRP78/BiP and PERK were highly expressed in 58% (15/26) and 35% (9/26), respectively. The high expression of GRP78/BiP was significantly associated with PERK, cell proliferation and angiogenesis.

Areca nut contributes to oral malignancy through facilitating the conversion of cancer stem cells

Oral cancer is one of the most frequent malignant diseases worldwide, and areca nut is a primary carcinogen causing this cancer in Southeast Asia. Previous studies to examine the effects of this carcinogen often used short-term and high-dose treatment of area nut extract as a research model, which do not recapitulate the conditions of patients with long-term and habitual use of this substance. To approach authentic mechanism of areca nut-induced oral carcinogenesis that occurs in human, we established four isogenic sublines of oral cells which were chronic exposed to areca nut extract. Without eliciting cytotoxicity or senescence, these four sublines cells exhibited significant increase in invasive ability, along with epithelial-mesenchymal transition. These cells also showed resistance to chemotherapeutic drug and irradiation, accompanying with the augmentation of ABCG2 protein efflux and increased ROS clearance. Moreover, these sublines possessed the characteristics of cancer stemness, as demonstrated by enriched CD24-/CD44+ and CD133+ sub-populations, enhanced spheroid cell formation, and induced expressions of pluripotent stemness regulators, including Gp96, Grp78, Slug, Sox9, Snail, and Foxc2. These stemness regulators were further shown up-regulations in oral cancer patients with areca nut-chewing habit, and were statistically correlated with CD44 expression, a stemness marker. In conclusion, our findings suggested that areca nut contributes to oral malignancy through facilitating the conversion of cancer stem cells. This study may further contribute to clinical applications in disease prevention, risk assessment or molecular therapeutics on areca nut- associated diseases.

Multivariate analyses of Ki-67, cytokeratin 13 and cytokeratin 17 in diagnosis and prognosis of oral precancerous lesions

BACKGROUND

Ki-67, cytokeratin 13, and/or cytokeratin 17 detection by immunohistochemistry has been reported to be useful for the diagnosis of oral precancerous lesions. However, the use of these markers remains controversial because of the lack of appropriately designed statistical studies. We assessed the hypothesis that Ki-67, cytokeratin 13, or cytokeratin 17 immunohistochemistry could facilitate the diagnosis of oral precancerous lesions and/or predict prognosis.

METHODS

Epithelial dysplasia was classified as low grade (none or mild dysplasia) or high grade (moderate dysplasia, severe dysplasia, or carcinoma in situ). This study included 58 low-grade and 36 high-grade dysplasia cases. We used logistic regression to assess the diagnostic values of Ki-67, cytokeratin 13, and cytokeratin 17 for high-grade dysplasia. Correlations between these markers and the prognosis of oral atypical epithelium were assessed using the Cox proportional hazards model.

RESULTS

Ki-67 overexpression and cytokeratin 13 loss were independent diagnostic markers for high-grade dysplasia (odds ratios, 1.92 and 2.53; 95% confidence intervals, 1.03-3.58, and 1.19-5.38, respectively). The area under the curve of Ki-67 was 0.73 and that of cytokeratin 13 was 0.72. However, the combination of Ki-67 and cytokeratin 13 yielded the area under the curve of 0.78. Ki-67 overexpression was significantly associated with recurrence and/or malignant transformation of oral atypical epithelium (hazard ratio, 7.25; 95% confidence interval, 1.07-48.92).

CONCLUSIONS

Ki-67 overexpression and cytokeratin 13 loss may be useful for distinguishing oral precancerous lesions from reactive atypical epithelium. Moreover, Ki-67 overexpression may be a risk factor for recurrence and/or malignant transformation of oral atypical epithelium.

Secretome profiling of primary cells reveals that THBS2 is a salivary biomarker of oral cavity squamous cell carcinoma

Oral cavity squamous cell carcinoma (OSCC), which is a leading cause of cancer-related death worldwide, is frequently associated with poor prognosis and mortality. The discovery of body fluid-accessible biomarkers may help improve the detection of OSCC. In the present work, we established primary cell cultures derived from OSCC and adjacent noncancerous epithelium and performed comparative profiling of their secretomes. Using spectral counting-based label-free quantification, we found that 64 proteins were significantly higher in primary OSCC cells compared with primary adjacent noncancerous cells. We then retrieved the mRNA expression levels of these 64 proteins in oral cavity tumor and noncancerous tissues from public domain array-based transcriptome data sets and used this information to prioritize the biomarker candidates. We identified 19 candidates; among them, the protein levels of THBS2, UFD1L, and DNAJB11 were found to be elevated in OSCC tissues compared with adjacent noncancerous epithelia. Importantly, higher levels of THBS2 in OSCC tissues were associated with a higher overall pathological stage, positive perineural invasion, and a poorer prognosis. Moreover, the salivary levels of THBS2 in OSCC patients were elevated compared to those of noncancer controls. Our results collectively indicate that analysis of the primary cell secretome is a feasible strategy for biomarker identification, and that THBS2 is a potentially useful salivary marker for the detection of OSCC.

Grp78 as a therapeutic target for refractory head-neck cancer with CD24(-)CD44(+) stemness phenotype

Cancer stem cells are refractory to conventional therapy, which result to cancer metastasis and chemo-radioresistance. Grp78 is known to have important roles in cytoprotection and tumorigenesis in several cancers. We therefore examined whether Grp78 can serve as a therapeutic target for refractory stemness phenotype of head and neck cancer (HNC). Six HNC cell lines were used. Fluorescence-activated cell sorting (FACS) analysis was used to sort CD24(-)CD44(+) and Grp78(+) cells. The small interfering RNA (siRNA) knockdown and cDNA transfection were applied to examine the effects of Grp78 on cellular function. Western blot and confocol microscopy were used to determine the effects of downstream protein expressions. Xenografted mouse tumors and immunohistochemistry were used to validate the results. We found that Grp78 regulated the conversion of CD24(-)CD44(+) cells, a characteristic of HNC stem cells. The CD24(-)CD44(+)Grp78(+) cells showed superior chemo-radioresistance and invasion ability compared with CD24(-)CD44(+), Grp78(+) or the parental cells. Silencing Grp78 increased chemo-radiosensitivity, inhibited cell invasion, reverse epithelial-mesenchymal transition, suppressed cancer stemness, withdrew CD24(-)CD44(+) cell conversion and induced differentiated phenotype. Study in xenografted mice further showed that CD24(-)CD44(+)Grp78(+) cells exhibited highest tumorigenesis, compared with CD24(-)CD44(+) CD24(+)CD44(+) or the parental cells. Grp78 knockdown dramatically restrained tumor growth along with the inhibition of stem cell regulatory proteins Oct-4 and Slug. Grp78 may serve as a molecular target that can be further developed for eradication of refractory HNC with stemness phenotype.

The endoplasmic reticulum stress marker, glucose-regulated protein-78 (GRP78) in visceral adipocytes predicts endometrial cancer progression and patient survival

OBJECTIVE

Currently, accurately identifying endometrial cancer patients at high risk for recurrence remains poor. To ascertain if changes in the endoplasmic reticulum (ER) stress marker, glucose-regulated-protein-78 (GRP78) can serve as a prognosticator in endometrial cancer, we examined GRP78 expression in patient samples to determine its association with clinical outcome.

METHODS

A retrospective cohort study was conducted in endometrial cancer patients. Archived specimens of visceral adipocytes and paired endometrial tumors were analyzed by immunohistochemistry for GRP78 and another ER stress marker, C/EBP homologous protein (CHOP). Expression of these markers was correlated with clinico-pathological information and outcomes.

RESULTS

GRP78 expression in visceral adipocytes was detected in 95% of the 179 endometrial cancer patients with analyzable visceral adipocytes. Within individual samples, 24% of adipocytes (range, 0-90%, interquartile range 18%-38%) exhibited GRP78 expression. High visceral adipocyte GRP78 expression positively correlated with advanced-stage disease (p=0.007) and deep myometrial invasion (p=0.004). High visceral adipocyte GRP78 expression was significantly associated with decreased disease-free survival (DFS) in multivariate analyses (hazard ratio 2.88, 95% CI 1.37-6.04, p=0.005). CHOP expression paralleled the GRP78 expression in adipocytes (r=0.55, p<0.001) and in the tumor (p=0.018).

CONCLUSIONS

Our study demonstrates that the ER stress markers, GRP78 and CHOP, are elevated in endometrial cancer patients. Furthermore, GRP78 expression levels in visceral adipocytes from these patients were significantly correlated to disease stage and patient survival. Our results demonstrate, for the first time, that the GRP78 levels in endometrial cancer patients may be a prognosticator and aid with clinical risk stratification and focused surveillance.

Molecular chaperones as a common set of proteins that regulate the invasion phenotype of head and neck cancer

PURPOSE

The goal of this study was to establish a common set of molecules that regulate cell invasion in head and neck cancer (HNC).

EXPERIMENTAL DESIGN

Five invasive sublines derived from HNC cell lines were established using the Matrigel selection method. Proteomic technology, MetaCore algorithm, and reverse transcriptase-PCR methods were used to search for molecules that contribute to the invasion phenotype. Cellular functional analyses and clinical association studies were applied to examine the significance of the molecules.

RESULTS

Fifty-two proteins were identified in more than two of the four independent proteomic experiments, including 10 (19%) molecular chaperones. Seven chaperones were confirmed to be differentially expressed in five sublines, Hsp90α, Hsp90β, Hsp90-B1/Gp96, Hsp70-A5/Grp78, and HYOU1, that upregulate, whereas Hsp60 and glucosidase-α neutral AB (GANAB) downregulate. Four molecules were further investigated. In all cell lines, knockdown of Hsp60 or GANAB and silencing of Gp96 or Grp78 considerably enhanced or reduced cell migration and invasion, respectively. Clinical association studies consistently revealed that low levels of Hsp60 or GANAB and high levels of Gp96 or Grp78 are significantly associated with advanced cancer (P < 0.001 to P = 0.047, respectively, for the four molecules) and poor survival (P < 0.001 to P = 0.025, respectively, for the four molecules).

CONCLUSION

Our study defined molecular chaperones as a common set of proteins that regulate the invasion phenotype of HNC. Loss of the tumor suppression function of Hsp60 or GANAB and acquisition of the oncogenic function of Gp96 or Grp78 contribute to aggressive cancers. These molecules may serve as prognostic markers and targets for cancer drug development.

Elimination of head and neck cancer initiating cells through targeting glucose regulated protein78 signaling

Background

Head and neck squamous cell carcinoma (HNSCC) is a highly lethal cancer that contains cellular and functional heterogeneity. Previously, we enriched a subpopulation of highly tumorigenic head and neck cancer initiating cells (HN-CICs) from HNSCC. However, the molecular mechanisms by which to govern the characteristics of HN-CICs remain unclear. GRP78, a stress-inducible endoplasmic reticulum chaperone, has been reported to play a crucial role in the maintenance of embryonic stem cells, but the role of GRP78 in CICs has not been elucidated.

Results

Initially, we recognized GRP78 as a putative candidate on mediating the stemness and tumorigenic properties of HN-CICs by differential systemic analyses. Subsequently, cells with GRP78 anchored at the plasma membrane (^memGRP78⁺) exerted cancer stemness properties of self-renewal, differentiation and radioresistance. Of note, xenotransplantation assay indicated merely 100 ^memGRP78⁺ HNSCCs resulted in tumor growth. Moreover, knockdown of GRP78 significantly reduced the self-renewal ability, side population cells and expression of stemness genes, but inversely promoted cell differentiation and apoptosis in HN-CICs. Targeting GRP78 also lessened tumorigenicity of HN-CICs both in vitro and in vivo. Clinically, co-expression of GRP78 and Nanog predicted the worse survival prognosis of HNSCC patients by immunohistochemical analyses. Finally, depletion of GRP78 in HN-CICs induced the expression of Bax, Caspase 3, and PTEN.

Conclusions

In summary, ^memGRP78 should be a novel surface marker for isolation of HN-CICs, and targeting GRP78 signaling might be a potential therapeutic strategy for HNSCC through eliminating HN-CICs.