Plasma osteopontin is an independent prognostic marker for head and neck cancers

Osteopontin is a prognostic circulating biomarker in patients with neuroendocrine neoplasms

PURPOSE

Osteopontin (OPN), also called secreted phosphoprotein 1 (SPP1) is a matricellular glycoprotein whose expression is elevated in various types of cancer and which has been shown to be involved in tumorigenesis and metastasis in many malignancies. Its role in neuroendocrine neoplasms (NEN) remains to be established. The aim of the study was to analyze plasma concentrations of OPN in patients with NEN and to explore its diagnostic and prognostic value as a clinical biomarker.

METHODS

OPN plasma concentrations were measured in a total of 38 patients with histologically proven NEN at three different time points during the course of disease and therapy (at the start of the study, after 3 and 12 months, respectively) as well as in healthy controls. Clinical and imaging data as well as concentrations of Chromogranin A (CgA) and Neuron Specific Enolase (NSE) were assessed.

RESULTS

OPN levels were significantly higher in patients with NEN compared to healthy controls. High-grade tumors (grade 3) showed the highest OPN levels. OPN levels were neither different between male and female patients nor between different primary tumor sites. OPN correlated significantly with corresponding NSE levels, while there was no correlation with Chromogranin A. High OPN levels above a cutoff value of 200 ng/ml at initial analysis predicted a worsened prognosis with significantly shorter progression-free survival of patients with NEN, which also held true within the subgroup of well-differentiated G1/G2 tumors.

CONCLUSION

Our data indicate that high baseline OPN levels in patients with NEN are predictive of an adverse outcome with shorter progression-free survival, even within the group of well differentiated G1/G2 tumors. Therefore, OPN may be used as a surrogate prognostic biomarker in patients with NEN.

Increased Circulating Osteopontin Levels Promote Primary Tumour Growth, but Do Not Induce Metastasis in Melanoma

Osteopontin (OPN) is a phosphoprotein with diverse functions in various physiological and pathological processes. OPN expression is increased in multiple cancers, and OPN within tumour tissue has been shown to promote key stages of cancer development. OPN levels are also elevated in the circulation of cancer patients, which in some cases has been correlated with enhanced metastatic propensity and poor prognosis. However, the precise impact of circulating OPN (cOPN) on tumour growth and progression remains insufficiently understood. To examine the role of cOPN, we used a melanoma model, in which we stably increased the levels of cOPN through adeno-associated virus-mediated transduction. We found that increased cOPN promoted the growth of primary tumours, but did not significantly alter the spontaneous metastasis of melanoma cells to the lymph nodes or lungs, despite an increase in the expression of multiple factors linked to tumour progression. To assess whether cOPN has a role at later stages of metastasis formation, we employed an experimental metastasis model, but again could not detect any increase in pulmonary metastasis in animals with elevated levels of cOPN. These results demonstrate that increased levels of OPN in the circulation play distinct roles during different stages of melanoma progression.

Outcome of Patients With Head and Neck Squamous Cell Carcinoma Can be Predicted by Expression of eIF4E and Osteopontin in Free Surgical Margins

Squamous cell carcinoma of the head and neck (HNSCC) is recognized as the third most common cause of death. Incomplete resection of the primary tumor is the main cause of local recurrence and poor prognosis in HNSCC. Histologic assessment in order to determine "tumor-free" margins could be inadequate because of malignant transformation occurs at the molecular level earlier than the morphologic level. The present study aimed to evaluate the prognostic significance of eukaryotic initiation factor 4E (eIF4E) and Osteopontin in the tumor cells and histologically tumor free surgical margins of HNSCC. This cohort study was performed on 60 cases of HNSCC diagnosed at the Department of Pathology and treated at the Clinical Oncology Department, Faculty of Medicine, Zagazig University. Our enrolled formalin fixed paraffin embedded biopsy specimens with their matched tumor free surgical margins from resected head and neck squamous cell carcinoma were immunostaind for eIF4E and Osteopontin markers. 65% of our HNSCC patients had eIF4 E positive cytoplasmic immunostaining and 70% of them exhibited Osteopontin staining. Two-thirds of the dead patients exhibited high Osteopontin positive staining, whereas the surviving group did not exhibit this high expression. Concerning eIF4E, 85% and 5% of the dead patients showed high and low eIF4E expression, respectively. Disease-free survival (DFS) and overall survival were significantly (P=0.000) different between high and negative expression of Osteopontin, high and negative expression of eIF4E. 84% of patients with eIF4E positive margins and 75% with Osteopontin positive margins had local recurrence. In addition, negative expression of eIF4E is associated with highly significant better DFS and overall survival (P=0.000 and 0.001), respectively, in the margin negative expression status, while negative expression of Osteopontin was significantly associated with better DFS but of no significance in overall survival outcome. Our findings suggest that tumor-free surgical margins in HNSCC may be redefined as histologically Osteopontin and eIF4E negative resection margins. However, multicenter prospective studies are required to further evaluate their clinical utility in the surgical management of primary HNSCC.

Cancer-Associated Fibroblasts in Oral Cancer: A Current Perspective on Function and Potential for Therapeutic Targeting

The role of the tumour microenvironement (TME) in cancer progression and resistance to therapies is now widely recognized. The most prominent non-immune cell type in the microenvironment of oral cancer (OSCC) is cancer-associated fibroblasts (CAF). Although CAF are a poorly characterised and heterogenous cell population, those with an "activated" myofibroblastic phenotype have been shown to support OSCC progression, promoting growth, invasion and numerous other "hallmarks of malignancy." CAF also confer broad resistance to different types of therapy, including chemo/radiotherapy and EGFR inhibitors; consistent with this, CAF-rich OSCC are associated with poor prognosis. In recent years, much CAF research has focused on their immunological role in the tumour microenvironment, showing that CAF shield tumours from immune attack through multiple mechanisms, and particularly on their role in promoting resistance to anti-PD-1/PD-L1 checkpoint inhibitors, an exciting development for the treatment of recurrent/metastatic oral cancer, but which fails in most patients. This review summarises our current understanding of CAF subtypes and function in OSCC and discusses the potential for targeting these cells therapeutically.

Osteopontin Levels in Patients with Squamous Metastatic Head and Neck Cancer

Background and Objectives: Increased osteopontin (OPN) concentrations in the plasma of patients with head and neck squamous cancer (HNSCC) have diagnostic significance, and it can indicate more aggressive biological behavior of cancer. The aim of this study was to determine OPN levels in patients with HNSCC of different primary locations and to assess its prognostic significance in metastasis development. Materials and Methods: This cohort study included 45 patients (41 male and 4 female patients) with HNSCC with different primary localization of head and neck. All patients underwent surgery—neck dissection. All patients were categorized according to the histological findings of the resected material and tumor–node–metastasis (TNM) classification system. After surgery, N categories were determined on the basis of histological features of resected material. Results: The histological findings of our patients showed: N0 in 11 patients, N1 in 8 patients, N2a in 4 patients, N2b in 14 patients and N2c in 8 patients. Plasma OPN values in all study participants ranged from 2.24 to 109.10 ng/mL. OPN levels in plasma of patients with negative nodes compared to the group of patients with positive nodes in the neck differed significantly (16.89 ng/mL to 34.08 ng/mL, respectively; p = 0.03). There were significantly lower OPN plasma levels in the group of subjects with histologically positive one lymph node in the neck (N1) compared to the group of patients with N2b histologically positive findings of resected neck material (10.4 ng/mL to 43.9 ng/mL, respectively; p = 0.02). Conclusions: The results have shown that growing N degrees of positive neck nodes classification were accompanied by growing values of plasma osteopontin. Osteopontin might be important for the development of neck metastases.

Osteopontin: A Key Regulator of Tumor Progression and Immunomodulation

Simple Summary

Anti-PD-1/PD-L1 and anti-CTLA-4-based immune checkpoint blockade (ICB) immunotherapy have recently emerged as a breakthrough in human cancer treatment. Durable efficacy has been achieved in many types of human cancers. However, not all human cancers respond to current ICB immunotherapy and only a fraction of the responsive cancers exhibit efficacy. Osteopontin (OPN) expression is highly elevated in human cancers and functions as a tumor promoter. Emerging data suggest that OPN may also regulate immune cell function in the tumor microenvironment. This review aims at OPN function in human cancer progression and new findings of OPN as a new immune checkpoint. We propose that OPN compensates PD-L1 function to promote tumor immune evasion, which may underlie human cancer non-response to current ICB immunotherapy.

Abstract

OPN is a multifunctional phosphoglycoprotein expressed in a wide range of cells, including osteoclasts, osteoblasts, neurons, epithelial cells, T, B, NK, NK T, myeloid, and innate lymphoid cells. OPN plays an important role in diverse biological processes and is implicated in multiple diseases such as cardiovascular, diabetes, kidney, proinflammatory, fibrosis, nephrolithiasis, wound healing, and cancer. In cancer patients, overexpressed OPN is often detected in the tumor microenvironment and elevated serum OPN level is correlated with poor prognosis. Initially identified in activated T cells and termed as early T cell activation gene, OPN links innate cells to adaptive cells in immune response to infection and cancer. Recent single cell RNA sequencing revealed that OPN is primarily expressed in tumor cells and tumor-infiltrating myeloid cells in human cancer patients. Emerging experimental data reveal a key role of OPN is tumor immune evasion through regulating macrophage polarization, recruitment, and inhibition of T cell activation in the tumor microenvironment. Therefore, in addition to its well-established direct tumor cell promotion function, OPN also acts as an immune checkpoint to negatively regulate T cell activation. The OPN protein level is highly elevated in peripheral blood of human cancer patients. OPN blockade immunotherapy with OPN neutralization monoclonal antibodies (mAbs) thus represents an attractive approach in human cancer immunotherapy.

Tumor Hypoxia: Impact on Radiation Therapy and Molecular Pathways

Tumor hypoxia is a common feature of the microenvironment in solid tumors, primarily due to an inadequate, and heterogeneous vascular network. It is associated with resistance to radiotherapy and results in a poorer clinical outcome. The presence of hypoxia in tumors can be identified by various invasive and non-invasive techniques, and there are a number of approaches by which hypoxia can be modified to improve outcome. However, despite these factors and the ongoing extensive pre-clinical studies, the clinical focus on hypoxia is still to a large extent lacking. Hypoxia is a major cellular stress factor and affects a wide range of molecular pathways, and further understanding of the molecular processes involved may lead to greater clinical applicability of hypoxic modifiers. This review is a discussion of the characteristics of tumor hypoxia, hypoxia-related molecular pathways, and the role of hypoxia in treatment resistance. Understanding the molecular aspects of hypoxia will improve our ability to clinically monitor hypoxia and to predict and modify the therapeutic response.

A comparative study of osteopontin expression, Ki67 index and prognosis in squamous cell carcinoma and cysts of the oral cavity

Background

Recent studies have shown a strong relationship between the expression of osteopontin and oral carcinogenesis. Osteopontin (OPN) has been shown to play a major role in regulating the aggressiveness of cancer cells and promote tumor growth. Odontogenic cysts are an essential aspect of oral and maxillofacial pathology. They are relatively frequent lesions with different clinical behavior. Some of them may have a proliferative pattern of growth and neoplastic nature. Evaluation of osteopontin expression with Ki-67 index may help examine clinical behavior and recurrence of oral squamous cell cancer and radicular cyst patients.

Methods

A total of 44 oral cavity cancer cases and 21 cysts samples were analyzed by immunohistochemical staining. Data used for analysis were derived from medical records. The following information was obtained from all patients’ medical records: survival, age, sex, lymph node status, tumor size, and location, as well as grade and histologic type of tumor. Expression status of OPN and Ki-67 was statistically assessed.

Results

Our data demonstrated that for summary immunoreactive scores of OPN and Ki-67 expressions in OSCC vs. RC patients statistical significance was found for both markers’ between OSCC and RC groups. Moreover, osteopontin is significantly higher expressed in larger OSCC tumors.

Conclusions

In conclusion, the role of OPN expression both in oral squamous cancer cells and radicular cyst and possible correlation with demographic and clinicopathological features remain undetermined in some aspects, further high-powered studies to develop a more standardized assessment of Ki-67 and osteopontin expression in OSCC and are needed.

Hypoxia-activated prodrugs and (lack of) clinical progress: The need for hypoxia-based biomarker patient selection in phase III clinical trials

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Hypoxia-activated prodrugs have yielded promising results up to phase II trials.

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Implementation of hypoxia-activated prodrugs in the clinic has not been successful.

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Phase III clinical trials lack patient stratification based on tumor hypoxia status.

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Stratification will decrease the number of patients needed and increase success.

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Improvements in hypoxia-activated prodrug design can also increase success rates.

Hypoxia-activated prodrugs (HAPs) are designed to specifically target the hypoxic cells of tumors, which are an important cause of treatment resistance to conventional therapies. Despite promising preclinical and clinical phase I and II results, the most important of which are described in this review, the implementation of hypoxia-activated prodrugs in the clinic has, so far, not been successful. The lack of stratification of patients based on tumor hypoxia status, which can vary widely, is sufficient to account for the failure of phase III trials. To fully exploit the potential of hypoxia-activated prodrugs, hypoxia stratification of patients is needed. Here, we propose a biomarker-stratified enriched Phase III study design in which only biomarker-positive (i.e. hypoxia-positive) patients are randomized between standard treatment and the combination of standard treatment with a hypoxia-activated prodrug. This implies the necessity of a Phase II study in which the biomarker or a combination of biomarkers will be evaluated. The total number of patients needed for both clinical studies will be far lower than in currently used randomize-all designs. In addition, we elaborate on the improvements in HAP design that are feasible to increase the treatment success rates.

Cancer-associated Fibroblast-derived IL-6 Promotes Head and Neck Cancer Progression via the Osteopontin-NF-kappa B Signaling Pathway

Osteopontin (OPN), a chemokine-like protein, plays a crucial role in the proliferation and metastasis of various cancers. However, how tumor stroma modulates the expression of neoplastic OPN and the multifaceted roles of OPN in head and neck cancer (HNC) are unclear. In this study, we tried to investigate the bridging role of OPN between tumor stroma and cancer cells.

Methods: Immunohistochemical staining and quantitative real-time PCR were used to detect OPN expression in HNC tissues, and the correlations between OPN expression and clinicopathologic features were then analyzed. We used a co-culture assay to study the modulatory role of IL-6 on OPN expression and immunoprecipitation analysis was used to determine the endogenous interaction between OPN and integrin αvβ3. Furthermore, a xenograft assay was carried out to confirm the tumor-promoting role and the potential therapeutic value of OPN in HNC.

Results: We found that OPN was significantly up-regulated in HNCs, and the elevated OPN was correlated with poor prognosis. Moreover, we identified IL-6 secreted by cancer-associated fibroblasts (CAFs) as the major upstream molecule that triggers the induction of neoplastic OPN. As such, during the interaction of fibroblasts and cancer cells, the increased neoplastic OPN induced by stromal IL-6 accelerated the growth, migration and invasion of cancer cells. More importantly, we also showed that soluble OPN could promote HNC progression via the integrin αvβ3-NF-kappa B pathway, and the combination of OPN and IL-6 had a better prognostic and diagnostic performance in HNC than either molecule alone.

Conclusion: Our study identified a novel modulatory role for OPN in HNC progression and further demonstrated that the combination of OPN and IL-6 might be a promising prognostic and diagnostic indicator as well as a potential cancer therapeutic target.

Serum, plasma and saliva biomarkers for head and neck cancer

INTRODUCTION

Head and neck squamous cell carcinoma (HNSCC) encompasses tumors arising from several locations (oral and nasal cavities, paranasal sinuses, salivary glands, pharynx, and larynx) and currently stands as the sixth most common cancer worldwide. The most important risk factors identified so far are tobacco and alcohol consumption, and, for a subgroup of HNSCCs, infection with high-risk types of human papillomavirus (HPV). Despite several improvements in the treatment of these tumors in the last decades, overall survival rates have only improved marginally, mainly due to the advanced clinical stage at diagnosis and the high rates of treatment failure associated with this late diagnosis. Areas covered: This review will focus on the feasibility of evaluating molecular-based biomarkers (mRNA, microRNA, lncRNA, DNA methylation and protein expression) in body fluids (serum, plasma, and saliva) as markers for diagnosis, prognosis, and surveillance. Expert commentary: The potential use of those markers in the clinical setting would allow for early diagnosis, prediction of treatment response, improvement in treatment selection and provide disease monitoring for early detection of tumor recurrence. It can ultimately be translated into better survival rates and improved quality of life for HNSCC patients.

Perioperative changes in osteopontin and TGFβ1 plasma levels and their prognostic impact for radiotherapy in head and neck cancer

Background

In head and neck cancer little is known about the kinetics of osteopontin (OPN) expression after tumor resection. In this study we evaluated the time course of OPN plasma levels before and after surgery.

Methods

Between 2011 and 2013 41 consecutive head and neck cancer patients were enrolled in a prospective study (group A). At different time points plasma samples were collected: T0) before, T1) 1 day, T2) 1 week and T3) 4 weeks after surgery. Osteopontin and TGFβ1 plasma concentrations were measured with a commercial ELISA system. Data were compared to 131 head and neck cancer patients treated with primary (n = 42) or postoperative radiotherapy (n = 89; group B1 and B2).

Results

A significant OPN increase was seen as early as 1 day after surgery (T0 to T1, p < 0.01). OPN levels decreased to base line 3-4 weeks after surgery. OPN values were correlated with postoperative TGFβ1 expression suggesting a relation to wound healing. Survival analysis showed a significant benefit for patients with lower OPN levels both in the primary and postoperative radiotherapy group (B1: 33 vs 11.5 months, p = 0.017, B2: median not reached vs 33.4, p = 0.031). TGFβ1 was also of prognostic significance in group B1 (33.0 vs 10.7 months, p = 0.003).

Conclusions

Patients with head and neck cancer showed an increase in osteopontin plasma levels directly after surgery. Four weeks later OPN concentration decreased to pre-surgery levels. This long lasting increase was presumably associated to wound healing. Both pretherapeutic osteopontin and TGFβ1 had prognostic impact.

Plasma Biomarker Enrichment of Clinical Prognostic Indices in Malignant Pleural Mesothelioma

OBJECTIVES

Prognostic models for malignant pleural mesothelioma (MPM) are needed to prevent potentially futile outcomes. We combined MPM plasma biomarkers with validated clinical prognostic indices to determine whether stratification of risk for death in 194 patients with MPM improved.

METHODS

Individuals were recruited from three different centers: a discovery cohort (83 patients with MPM) created by combining patients from two U.S. centers and a separate, independent cohort from Canada (111 patients with MPM). Univariable and multivariable analyses were performed on the initial discovery and independent cohorts separately. In the multivariable analyses, prognostic factors were adjusted for the European Organisation for Research and Treatment of Cancer (EORTC) prognostic index (PI) of mesothelioma. The prognostic significance of adding plasma biomarker data to the PI was determined by using the likelihood ratio test, comparing models with and without the addition of biomarker to the clinical PI. The predictive ability of the biomarker was then assessed formally using Harrell's C-index by applying the fitted model variables of the discovery cohort to the second, independent cohort, including and not including the biomarker with the PI.

RESULTS

Higher levels of osteopontin and mesothelin were individually associated with worse prognosis after adjusting for the PI. In the independent cohort, incorporating either plasma osteopontin or mesothelin into the baseline predictive PI model substantively and statistically significantly improved Harrell's C-statistic. In the final prognostic model, log-osteopontin, EORTC clinical prognostic index, and hemoglobin remained as independently significant predictors and the entire prognostic model improved the optimism-corrected Harrell's C-index significantly, from 0.718 (0.67-0.77) to 0.801 (0.77-0.84).

CONCLUSIONS

These data suggest a possible role for preoperative plasma biomarkers to improve the prognostic capability of the EORTC PI of MPM.

TGFβ3-mediated induction of Periostin facilitates head and neck cancer growth and is associated with metastasis

The matrix-specific protein periostin (POSTN) is up-regulated in human cancers and associated with cancer growth, metastasis and angiogenesis. Although the stroma of cancer tissues is the main source of POSTN, it is still unclear how POSTN plays a role to facilitate the interplay between cancer cells and cancer-associated fibroblasts (CAFs) in head and neck cancer (HNC), thereby promoting tumorigenesis via modifying the tumor microenvironment. Herein, we have performed studies to investigate POSTN and its role in HNC microenvironment. Our results indicated that POSTN was significantly up-regulated in HNCs, especially in the tissues with lymph node metastasis. Moreover, POSTN was highly enriched in the stroma of cancer tissues and produced mainly by CAFs. More importantly, we have pinpointed TGF-β3 as the major upstream molecular that triggers the induction of POSTN in CAFs. As such, during the interaction between fibroblasts and cancer cells, the increased stromal POSTN induced by TGF-β3 directly accelerated the growth, migration and invasion of cancer cells. Hence, our study has provided a novel modulative role for POSTN on HNC progression and further reveals POSTN as an effective biomarker to predict metastasis as well as a potential cancer therapeutic target.

Hypoxia as a Biomarker and for Personalized Radiation Oncology

Tumor hypoxia is a clinically relevant cause of radiation resistance. Direct measurements of tumor oxygenation have been performed predominantly with the Eppendorf histograph and these have defined the reduced prognosis after radiotherapy in poorly oxygenated tumors, especially head-and-neck cancer, cervix cancer and sarcoma. Exogenous markers have been used for immunohistochemical detection of hypoxic tumor areas (pimonidazole) or for positron-emission tomography (PET) imaging (misonidazole). Overexpression of hypoxia-related proteins such as hypoxia-inducible factor-1α (HIF-1α) has also been linked to poor prognosis after radiotherapy and such proteins are considered as potential endogenous hypoxia markers.

Expression of Osteopontin in Oral Squamous Cell Carcinoma and its Surgical Margins-An Immunohistochemical Study

INTRODUCTION

Despite the advances in the treatment modalities offered for oral squamous cell carcinoma. The recurrence rate of it still remains quite high. Early detection of recurrence will improve the outcome and the survival of the patient. Osteopontin, a transformation-related phosphorylated protein in epithelial cells has been closely related with tumourigenesis. This study was undertaken to explore the potential of OPN as a tumour marker of recurrence in OSCC.

AIM

To analyse the expression of Osteopontin (OPN) in Oral Squamous Cell Carcinoma (OSCC), patient matched tumour free surgical margins and normal oral mucosa and to correlate with local & loco regional recurrence.

MATERIALS AND METHODS

Twenty cases each of formalin fixed paraffin embedded blocks of histopathologically diagnosed cases of OSCC, patient matched tumour free surgical margins and normal oral mucosal tissues were obtained from the archives of the Oral Pathology & Microbiology Department, Faculty of Dental Sciences, SRU and Govt. Arignar Anna Memorial Cancer Hospital, Kancheepuram. Immunohistochemical analysis was performed with an antibody to Osteopontin protein. Patients with secondary tumours and those treated with chemotherapy and radiotherapy were excluded from this study.

RESULTS

The expression of OPN was elevated in 95% of tumours & 55% of histologically tumour free margin samples. There was negative OPN expression in normal mucosal samples. The result of the study was statistically analysed using Pearson chi-square test and was found to be statistically significant.

CONCLUSION

OPN can be used as a diagnostic marker in Oral Squamous Cell Carcinoma. In the tumour free surgical margins, elevated levels of OPN may predict a significantly increased risk of recurrence.

Influence of hypoxia and irradiation on osteopontin expression in head and neck cancer and glioblastoma cell lines

Background

Tumor hypoxia is a known risk factor for reduced response to radiotherapy. The evaluation of noninvasive methods for the detection of hypoxia is therefore of interest. Osteopontin (OPN) has been discussed as an endogenous hypoxia biomarker. It is overexpressed in many cancers and is involved in tumor progression and metastasis.

Methods

To examine the influence of hypoxia and irradiation on osteopontin expression we used different cell lines (head and neck cancer (Cal27 and FaDu) and glioblastoma multiforme (U251 and U87)). Cells were treated with hypoxia for 24 h and were then irradiated with doses of 2 and 8 Gy. Osteopontin expression was analyzed on mRNA level by quantitative real-time RT-PCR (qPCR) and on protein level by western blot. Cell culture supernatants were evaluated for secreted OPN by ELISA.

Results

Hypoxia caused an increase in osteopontin protein expression in all cell lines. In Cal27 a corresponding increase in OPN mRNA expression was observed. In contrast the other cell lines showed a reduced mRNA expression under hypoxic conditions. After irradiation OPN mRNA expression raised slightly in FaDu and U87 cells while it was reduced in U251 and stable in Cal27 cells under normoxia. The combined treatment (hypoxia and irradiation) led to a slight increase of OPN mRNA after 2 Gy in U251 (24 h) and in U87 (24 and 48 h) cell lines falling back to base line after 8 Gy. This effect was not seen in Cal27 or in FaDu cells. Secreted OPN was detected only in the two glioblastoma cell lines with reduced protein levels under hypoxic conditions. Again the combined treatment resulted in a minor increase in OPN secretion 48 hours after irradiation with 8 Gy.

Conclusion

Osteopontin expression is strongly modulated by hypoxia and only to a minor extent by irradiation. Intracellular OPN homeostasis seems to vary considerably between cell lines. This may explain the partly conflicting results concerning response prediction and prognosis in the clinical setting.

OPN -Revisited

Osteopontin (OPN), a matrix extracellular glyco-phosphoprotein is found in various tissues such as epithelium lined tissues, kidney, bone and teeth .It is also detected in all body fluids including blood and breast milk. OPN plays role in a number of physiological and pathologic events such as cell adhesion, migration and cell survival, angiogenesis, apoptosis, inflammation and wound healing. This review summarizes the current data of the biological activities of OPN in the development of tumour, its progression and metastasis.

Quantitative urinary proteomics using stable isotope labelling by peptide dimethylation in patients with prostate cancer

Prostate cancer (PCa) is the most commonly diagnosed malignancy in men. The current prevalent diagnosis method, prostate-specific antigen (PSA) screening test, has low sensitivity, specificity and is poor at predicting the grade of disease. Thus, new biomarkers are urgently needed to improve the PCa diagnosis and staging for the management of patients. The aim of this study is to investigate the first voided urinary sample after massage for biomarker discovery for PCa. In this work, untargeted metabolomic profiling of the first voided urinary sample after massage from 28 confirmed prostate cancer patients, 20 benign enlarged prostate patients and 6 healthy volunteers was performed using liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-MS/MS). Single and multiple peptide protein and cross-linking molecules were identified using PEAKS software. Analytical and diagnostic performance was tested using the Student's t test, Benjamini Hochberg correction and the receiver operating characteristic (ROC) curves. Using differential display analysis to compare peptides and cross-linking molecules of urinary samples between patients with benign, enlarged prostate and malignant cancer, we identified multiple peptides derived from osteopontin (SPP1) and prothrombin (F2) that are lower in PCa patients than in benign and enlarged prostate. The diagnosis accuracies of SPP1 and F2 peptides are 0.65-0.77 and 0.68-0.72, respectively. In addition to this, there are significant differences between PCa and benign/enlarged prostate patients in pyridinoline (PYD) and deoxypyridinoline (DPD) (p value = 0.001). Differences also, as shown in the excretion of these molecules for different stages of PCa (p value = 0.04) as the level of DPD and DPD/PYD ratio, were high in patients with locally advanced tumours. The study underscores the importance of proteomics analysis, and our results demonstrate that a urinary-based in depth proteomic approach allows the potential identification of dysregulated pathways and diagnostic biomarkers.

Osteopontin-integrin α(v)β(3) axis is crucial for 5-fluorouracil resistance in oral squamous cell carcinoma

Clinical applications of a chemotherapeutic agent, 5-fluorouracil (5-FU) in oral squamous cell carcinoma (OSCC) have been limited because of drug resistance. This study aimed to identify novel mechanisms of 5-FU resistance. Here we found increased osteopontin (OPN) gene expression in OSCC tissues with resistance to 5-FU-based chemoradiotherapy. OPN overexpression in OSCC cells led to 5-FU resistance and abrogated the prosurvival effect of the drug in a mouse xenograft model. OPN-induced 5-FU resistance required integrin αvβ3. Targeting integrin αvβ3 reversed the resistance in a 5-FU-resistant clone highly expressing OPN. Our data suggest that the OPN-integrin αvβ3 axis is crucial for 5-FU resistance in OSCC.

Prognostic information of serial plasma osteopontin measurement in radiotherapy of non-small-cell lung cancer

Background

Circulating baseline levels of the plasma-protein osteopontin (OPN) have been suggested as a prognostic indicator in chemotherapy and surgery for lung cancer. However, the role of this hypoxia-related protein in radiotherapy of lung cancer is unclear. We previously demonstrated the prognostic effect of baseline OPN plasma levels which was increased by co-detection with other hypoxia-related proteins in the radical radiotherapy of non-small-cell lung cancer (NSCLC). This prospective clinical study investigated whether serial OPN measurements during and after curative-intent radiotherapy for NSCLC provide additional or superior prognostic information.

Methods

Sixty-nine patients with inoperable NSCLC were prospectively enrolled (55 M0, 14 M1). OPN plasma levels were measured before (t0), at the end (t1) and four weeks after radiotherapy (t2) by ELISA, compared between M0 and M1 patients and correlated with clinicopathological parameters. OPN levels were monitored over time and correlated with prognosis in M0-stage patients treated by radical 66-Gy radiotherapy ± chemotherapy.

Results

Pre-treatment OPN levels were associated with T stage (p = .03), lung function (p = .002), weight loss (p = .01), tumor volume (p = .02) and hemoglobin concentration (p = 04). M1 patients had significantly elevated OPN levels at all time points (p < .001). Patients with increasing OPN levels after radiotherapy had inferior freedom from relapse (p = .008), overall survival (p = .004) and disease-free survival (p = .001) compared to patients with stable or decreasing OPN levels. The risk of relapse in patients with increasing or stable OPN levels after radiotherapy was increased by a factor of 2.9 (p = .01). Patients with increasing post-treatment OPN levels had a 3.1-fold increased risk of death (p = .003). In an exploratory multivariate model, post-treatment OPN level changes but not absolute baseline OPN levels remained an independent prognostic factor for overall survival (p = .002) with a 3.6-fold increased risk of death, as well as N stage (p = .006).

Conclusions

Our results suggest that OPN level changes over time, particularly post-treatment, may yield additional prognostic information in curative-intent radiotherapy of NSCLC.

Evaluating the efficacy of osteopontin expression as a prognostic marker in oral squamous cell carcinoma in the Indian subpopulation

Aim:

This study aimed to correlate the prognostic value of osteopontin (OPN) expression using both tissue and plasma samples from patients with clinically and histologically confirmed oral squamous cell carcinoma (OSCC).

Methods and Materials:

The study group comprised of sixty patients (n = 60), which were clinically and histologically diagnosed for oral squamous cell carcinoma (OSCC). The Control group comprised of ten (n = 10) healthy volunteers. Plasma OPN levels were assayed using a quantitative enzyme-linked immunosorbent assay (OPN ELISA). Expression of OPN was also identified and evaluated by immunohistochemistry in tissue sections. These OPN expressions were then correlated with different parameters like age, sex, site, clinical presentation, tumor node metastasis (TNM) staging, histopathological grading and lymph node metastasis.

Statistical Analysis:

One-way analysis of variance (ANOVA) was used to evaluate the difference in tissue intensity and plasma OPN levels between the OSCC and the normal control groups.

Results:

The distribution of the plasma OPN levels and tissue OPN intensity in OSCC cohorts were compared to histopathological grades and analyzed. When evaluated OPN expression in tissue had higher intensity observed in OSCC (95% +ve) cases. And the mean plasma OPN concentration in OSCC cohort was more in comparison to the normal cohort. The results clearly showed that the plasma OPN levels and intensity grading in tissue correlated with tumor grades.

Conclusion:

The study highlights OPN as a biomarker for prognosis in OSCC in both plasma and tissue samples. We would like to emphasize on the evaluation of plasma OPN as a protocol of blood examination for all cancer patient, as it may serve as an indicator for tumor progression and potential risk of metastasis.

TGM3, a candidate tumor suppressor gene, contributes to human head and neck cancer

BACKGROUND

In our previous study using oligonucleotide microarrays, we revealed that transglutaminase 3 (TGM3) was remarkably down-regulated in head and neck cancer (HNC). However, the potential of TGM3 as a useful biomarker or molecular target for HNC is unclear.

METHODS

The transcriptional and post-translational status of TGM3 in HNC cell lines and specimens was detected using real-time PCR and western blot analysis. Bisulfate-treated DNA sequencing was used to analyze the molecular mechanism of TGM3 gene silencing. In addition, the effects of TGM3 on the proliferation, colony formation and induction of apoptosis in vitro and tumorigenicity in vivo were investigated through exogenous expression of TGM3 in HNC cells. Immunohistochemistry was used to evaluate TGM3 expression in large HNC samples.

RESULTS

TGM3 was down-regulated in HNC samples and cell lines (P < 0.0001). The hypermethylation of a promoter CpG island was one of the mechanisms of silencing the TGM3 gene in HNC. Exogenous expression of TGM3 in HNC cells could inhibit the proliferation and enhance the apoptosis of HNC cells in vitro and suppress tumor growth in vivo. In addition, TGM3 protein levels were strongly associated with the pathological differentiation of HNC tissues (P = 0.0037). Survival analysis revealed that low TGM3 expression was associated with worse overall survival (P = 0.0002), and TGM3 expression level was an independent predictor in patients with HNC.

CONCLUSIONS

The studies prove that TGM3, as a candidate tumor suppressor, contributes to the carcinogenesis and development of HNC and may serve as a useful biomarker for patients with HNC.

Osteopontin expression is an independent factor for poor survival in oral squamous cell carcinoma: a computer-assisted analysis on TMA sections

INTRODUCTION

Osteopontin (OPN) is non-collagenous extracellular matrix protein involved in various physiological and pathological events, including tumor progression. The aim of this study was to analyze the expression of OPN in normal oral mucosa and oral squamous cell carcinoma (OSCC) and to assess its prognostic significance.

METHODS

The expression of OPN was immunohistochemicaly analyzed in 86 OSCC and compared with clinicopathological variable such as tumor size, nodal stage, WHO clinical stage, Ki-67 proliferation index, and patients' outcome. OPN mRNA was analyzed using quantitative real-time PCR and compared with protein OPN expression and clinical outcome in 18 OSCC samples.

RESULTS

The expression of OPN protein was found in OSCC tumor cells (t-OPN) and various stromal cells (s-OPN). High level of t-OPN expression was associated with higher nodal stage (P = 0.045), higher WHO clinical stage (P = 0.033), and poor clinical outcome (P = 0.022). In multivariate analysis, t-OPN emerged as an adverse independent factor for survival (P = 0.049). Although correlated with t-OPN (P = 0.005), s-OPN was not significantly associated with clinical parameters, including patients' outcome. Also, there was no association between OPN and clinical parameters at the mRNA level.

CONCLUSION

OPN is upregulated in tumor and stromal OSCC cells. Tumor cell-derived OPN is involved in tumor progression and can independently predict the clinical outcome. Stromal-derived OPN probably has a different function compared with OPN secreted from tumor cells.

Postoperative serum osteopontin level is a novel monitor for treatment response and tumor recurrence after resection of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Presurgery serum osteopontin (OPN) level has been demonstrated to correlate to tumor recurrence and survival of hepatocellular carcinoma (HCC) patients. This study investigated the postoperative dynamic changes of serum OPN level and its clinical significance in HCC patients.

METHODS

Presurgery serum OPN levels were measured by enzyme-linked immunosorbent assay in cohort A of 179 HCC patients and were compared with the multiple controls including different kinds of liver diseases and healthy individuals. In cohort B of 110 patients with resectable HCCs, besides preoperative assays, serum OPN was monitored at 1 week, 1, and ≥2 months after operation.

RESULTS

The baseline presurgery serum OPN of HCC patients was significantly higher than that of the patients with the other kinds of liver diseases (p < 0.0001). The prognostic values of presurgery serum OPN level in HCC patients were further confirmed. The postsurgery OPN levels were significantly elevated within 1 week after HCC resection, then decreased at 1 month and reached the nadir later than 2 months after operations. It increased again at the time of tumor recurrence, then declined after the second removal of recurrent HCCs. Moreover, postoperative OPN in α-fetoprotein-negative and -positive HCC patients had the same changing pattern; it only correlated to liver function and C-reactive protein level.

CONCLUSIONS

After a transient fluctuation, serum OPN levels significantly decrease after curative resection of HCCs. Postoperative serum OPN could serve as a surrogate serologic biomarker for monitoring treatment response and tumor recurrence after HCC resection, including α-fetoprotein-negative ones.

Effects of osteopontin inhibition on radiosensitivity of MDA-MB-231 breast cancer cells

Background

Osteopontin (OPN) is a secreted glycophosphoprotein that is overexpressed in various tumors, and high levels of OPN have been associated with poor prognosis of cancer patients. In patients with head and neck cancer, high OPN plasma levels have been associated with poor prognosis following radiotherapy. Since little is known about the relationship between OPN expression and radiosensitivity, we investigated the cellular and radiation induced effects of OPN siRNA in human MDA-MB-231 breast cancer cells.

Methods

MDA-MB-231 cells were transfected with OPN-specific siRNAs and irradiated after 24 h. To verify the OPN knockdown, we measured the OPN mRNA and protein levels using qRT-PCR and Western blot analysis. Furthermore, the functional effects of OPN siRNAs were studied by assays to assess clonogenic survival, migration and induction of apoptosis.

Results

Treatment of MDA-MB-231 cells with OPN siRNAs resulted in an 80% decrease in the OPN mRNA level and in a decrease in extracellular OPN protein level. Transfection reduced clonogenic survival to 42% (p = 0.008), decreased the migration rate to 60% (p = 0.15) and increased apoptosis from 0.3% to 1.7% (p = 0.04). Combination of OPN siRNA and irradiation at 2 Gy resulted in a further reduction of clonogenic survival to 27% (p < 0.001), decreased the migration rate to 40% (p = 0.03) and increased apoptosis to 4% (p < 0.005). Furthermore, OPN knockdown caused a weak radiosensitization with an enhancement factor of 1.5 at 6 Gy (p = 0.09) and a dose modifying factor (DMF₁₀) of 1.1.

Conclusion

Our results suggest that an OPN knockdown improves radiobiological effects in MDA-MB-231 cells. Therefore, OPN seems to be an attractive target to improve the effectiveness of radiotherapy.

Identification of a biomarker panel using a multiplex proximity ligation assay improves accuracy of pancreatic cancer diagnosis

Background

Pancreatic cancer continues to prove difficult to clinically diagnose. Multiple simultaneous measurements of plasma biomarkers can increase sensitivity and selectivity of diagnosis. Proximity ligation assay (PLA) is a highly sensitive technique for multiplex detection of biomarkers in plasma with little or no interfering background signal.

Methods

We examined the plasma levels of 21 biomarkers in a clinically defined cohort of 52 locally advanced (Stage II/III) pancreatic ductal adenocarcinoma cases and 43 age-matched controls using a multiplex proximity ligation assay. The optimal biomarker panel for diagnosis was computed using a combination of the PAM algorithm and logistic regression modeling. Biomarkers that were significantly prognostic for survival in combination were determined using univariate and multivariate Cox survival models.

Results

Three markers, CA19-9, OPN and CHI3L1, measured in multiplex were found to have superior sensitivity for pancreatic cancer vs. CA19-9 alone (93% vs. 80%). In addition, we identified two markers, CEA and CA125, that when measured simultaneously have prognostic significance for survival for this clinical stage of pancreatic cancer (p < 0.003).

Conclusions

A multiplex panel assaying CA19-9, OPN and CHI3L1 in plasma improves accuracy of pancreatic cancer diagnosis. A panel assaying CEA and CA125 in plasma can predict survival for this clinical cohort of pancreatic cancer patients.

Small integrin-binding proteins as serum markers for prostate cancer detection

PURPOSE

The small integrin-binding ligand N-linked glycoprotein (SIBLING) gene family includes bone sialoprotein (BSP), dentin matrix protein 1 (DMP1), dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE), and osteopontin (OPN). Previous studies have separately reported elevated expression of BSP, OPN, or DSPP in prostate tumor paraffin sections. We hypothesized that SIBLINGs may be informative serum markers for subjects with prostate cancer.

METHODS

Expression levels of SIBLINGs in biopsies of normal tissue and tumors from prostate were determined by cDNA array and by immunohistochemical staining with monoclonal antibodies. Competitive ELISAs for measuring total BSP, DSPP, MEPE, and OPN were applied to a test group of 102 subjects with prostate cancer and 110 normal subjects and a validation group of 90 subjects.

RESULTS

BSP, DMP1, DSPP, and OPN exhibited elevated mRNA expression and protein levels in biopsies. BSP, DSPP, and OPN were elevated in serum from prostate cancer subjects, with serum DSPP exhibiting the greatest difference, yielding an area under the receiver operator characteristic curve value of 0.98. Serum BSP and OPN levels were significantly elevated only in late stages, whereas DSPP was significantly elevated at all stages. Optimal serum value cutoff points derived for BSP, OPN, and DSPP were applied as a validation test to a new group of 90 subjects and DSPP yielded a sensitivity of 90% and a specificity of 100%.

CONCLUSION

Of the SIBLING gene family members, DSPP appears to be a strong candidate for use in serum assays for prostate cancer detection.

Osteopontin is upregulated in malignant and inflammatory pleural effusions

BACKGROUND AND OBJECTIVE

Osteopontin (OPN) is an important mediator of inflammation and cancer progression. In the present study, we asked whether pleural fluid (PF) and serum OPN concentrations differed between patients with pleural effusions of different aetiologies, and whether assessment of OPN levels was useful for diagnostic purposes.

METHODS

One hundred and nine consecutive patients with pleural effusions of different aetiologies were recruited prospectively during daily clinics. OPN levels were measured by ELISA.

RESULTS

PF OPN levels were 10-fold higher in exudates than in transudates and were significantly correlated with markers of pleural inflammation and vascular hyper-permeability, such as PF/serum LDH or protein ratios, PF protein and PF vascular endothelial growth factor levels. Patients with malignant pleural effusions had higher PF and lower serum OPN concentrations than those with benign disease. The diagnostic accuracies of PF and PF/serum OPN for malignancy were 71.5% (95% CI: 64-80) and 70.6% (95% CI: 62-80), respectively.

CONCLUSIONS

OPN levels were elevated in exudative pleural effusions, as compared with the levels in blood or transudative pleural effusions. While PF and PF/serum OPN were higher in patients with malignancies, the diagnostic accuracy of the tests was not sufficient to permit routine use in clinical practice.

The relationship between human papillomavirus status and other molecular prognostic markers in head and neck squamous cell carcinomas

PURPOSE

To evaluate the relationship between human papillomavirus (HPV) status and known prognostic makers for head and neck cancers including tumor hypoxia, epidermal growth factor receptor (EGFR) expression and intratumoral T-cell levels and to determine the prognostic impact of these markers by HPV status.

METHODS AND MATERIALS

HPV status in 82 evaluable head and neck squamous cell carcinomas patients was determined by pyrosequencing and related to p16(INK4a) staining and treatment outcomes. It was correlated with tumor hypoxia (tumor pO(2) and carbonic anhydrase [CAIX] staining), EGFR status, and intratumoral lymphocyte expression (CD3 staining).

RESULTS

Forty-four percent of evaluable tumors had strong HPV signal by pyrosequencing. There was a significant relationship between strong HPV signal and p16(INK4a) staining as well as oropharynx location. The strong HPV signal group fared significantly better than others, both in time to progression (TTP, p = 0.008) and overall survival (OS, p = 0.004) for all patients and for the oropharyngeal subset. Positive p16(INK4a) staining was associated with better TTP (p = 0.014) and OS (p = 0.00002). There was no relationship between HPV status and tumor pO(2) or CAIX staining. However, HPV status correlated inversely with EGFR reactivity (p = 0.0006) and directly with CD3(+) T-lymphocyte level (p = 0.03). Whereas CAIX and EGFR overexpression were negative prognostic factors regardless of HPV status, CD3(+) T-cell levels was prognostic only in HPV(-) tumors.

CONCLUSION

HPV status was a prognostic factor for progression and survival. It correlated inversely with EGFR expression and directly with T-cell infiltration. The prognostic effect of CAIX and EGFR expression was not influenced by HPV status, whereas intratumoral T-cell levels was significant only for HPV(-) tumors.

Osteopontin promotes fibrosis in dystrophic mouse muscle by modulating immune cell subsets and intramuscular TGF-beta

Duchenne muscular dystrophy (DMD) is an X-linked, degenerative muscle disease that is exacerbated by secondary inflammation. Here, we characterized the immunological milieu of dystrophic muscle in mdx mice, a model of DMD, to identify potential therapeutic targets. We identified a specific subpopulation of cells expressing the Vbeta8.1/8.2 TCR that is predominant among TCR-beta+ T cells. These cells expressed high levels of osteopontin (OPN), a cytokine that promotes immune cell migration and survival. Elevated OPN levels correlated with the dystrophic process, since OPN was substantially elevated in the serum of mdx mice and muscle biopsies after disease onset. Muscle biopsies from individuals with DMD also had elevated OPN levels. To test the role of OPN in mdx muscle, mice lacking both OPN and dystrophin were generated and termed double-mutant mice (DMM mice). Reduced infiltration of NKT-like cells and neutrophils was observed in the muscle of DMM mice, supporting an immunomodulatory role for OPN in mdx muscle. Concomitantly, an increase in CD4+ and FoxP3+ Tregs was also observed in DMM muscle, which also showed reduced levels of TGF-beta, a known fibrosis mediator. These inflammatory changes correlated with increased strength and reduced diaphragm and cardiac fibrosis. These studies suggest that OPN may be a promising therapeutic target for reducing inflammation and fibrosis in individuals with DMD.

New Dual Monoclonal ELISA for Measuring Plasma Osteopontin as a Biomarker Associated with Survival in Prostate Cancer: Clinical Validation and Comparison of Multiple ELISAs

Background: A previously developed monoclonal/polyclonal ELISA (Mono/Poly) to detect plasma concentrations of osteopontin (OPN) was shown to provide prognostic information in breast, prostate, and other cancers. Here we describe the clinical validation of a new dual monoclonal (Dual Mono) assay. We compared both assays with 4 assays that recognize defined regions of OPN protein (dual polyclonal systems 5-1, 4-1, 4-3 and polyclonal-monoclonal system 1-3).

Methods: OPN sequences recognized by the monoclonal antibodies that make up the Dual Mono ELISA were identified by Pepscan CLIPS™ analysis. Using the 6 ELISAs, we measured OPN in plasma from 66 patients with castration-resistant prostate cancer, and we assessed the ability of each assay to predict patient survival.

Results: The assays varied in measured plasma OPN concentrations, with median values ranging from 112 to 1740 μg/L, and ability to predict patient survival. By Cox univariable regression of survival by tertiles of OPN, the Mono/Poly and Dual Mono ELISAs had the highest log-rank χ2 values. After adjustment for risk factors independently associated with survival in our samples, OPN remained associated with survival only for the Mono/Poly and Dual Mono systems.

Conclusions: OPN plasma values varied significantly depending on the assay used. Only the Mono/Poly and Dual Mono systems were independently associated with survival in a population of men with castration-resistant prostate cancer. The availability of a clinically validated, dual monoclonal–based ELISA will provide consistent reagents for studies of OPN plasma concentrations in cancer and other pathologies.

Comprehensive study on the prognostic role of osteopontin expression in oral squamous cell carcinoma

Osteopontin is a tumor-associated protein that promotes tumor development and metastasis. The preoperative blood samples of 94 oral squamous cell carcinoma (OSCC) patients and 28 healthy individuals were analyzed for plasma osteopontin levels, and another 256 paraffin-embedded OSCC specimens were analyzed by osteopontin immunostaining. The patients with advanced tumor (T) stage (T3/T4 vs. T1/T2) and positive nodal (N) status had significantly higher plasma levels of osteopontin (both p<0.001). Positive osteopontin immunostaining also correlated significantly with advanced T stage (p<0.001), positive N status (p<0.001), advanced TNM stage (p<0.001) and male gender (p=0.016). Unfavorable cumulative 5-year overall survival rates correlated significantly with positive osteopontin immunostaining (p<0.001), advanced T stage (p<0.001), positive N status (p<0.001) and advanced TNM stage (p<0.001). However, Cox regression analysis revealed that T stage and N status were independent prognostic factors for survival (both p<0.001) and osteopontin immunostaining was marginally significant for survival (p=0.056). The present study demonstrated that high expression level of osteopontin in either the plasma or the tumor of the patients with OSCC was associated with tumor progression, suggesting that osteopontin expression is an important prognostic factor for OSCC.

Hypoxia, angiogenesis, and lung cancer

Lung cancer is responsible for more deaths than any other cancer in America. As a result, novel ways to treat it are needed to improve patient outcomes. A tumor must form new blood vessels to grow and metastasize to distant sites; this angiogenesis is mediated by factors such as vascular endothelial growth factor (VEGF). Because it increases VEGF levels, hypoxia has been thought to be a primary trigger of angiogenesis. Tumor hypoxia and higher levels of serum markers of angiogenesis have been associated with poor prognosis in non-small cell lung cancer (NSCLC). In recent years, antiangiogenic compounds have been developed and tested in various solid malignancies, including NSCLC, for which bevacizumab, a monoclonal antibody against VEGF, was recently approved. Combinations of antiangiogenic drugs and conventional cytotoxic chemotherapy are currently under development.

Lower osteopontin plasma levels are associated with superior outcomes in advanced non-small-cell lung cancer patients receiving platinum-based chemotherapy: SWOG Study S0003

PURPOSE

S0003 was a phase III trial of carboplatin/paclitaxel with or without the hypoxic cytotoxin tirapazamine in patients with advanced or metastatic non-small-cell lung cancer (NSCLC). We investigated the relationship between clinical outcomes and plasma levels of the hypoxia-associated protein osteopontin (OPN) in patients on this protocol.

PATIENTS AND METHODS

Baseline plasma was obtained from 172 patients. In 56 patients, sequential plasma was obtained after one or two cycles. Concentrations of OPN, as well as plasminogen activator inhibitor-1 (PAI-1) and vascular endothelial growth factor (VEGF), were measured using enzyme-linked immunosorbent assay. Tumor expression of OPN was assessed by immunohistochemistry in 61 matched archival specimens.

RESULTS

Patients with lower OPN levels (below the median) had a significantly superior overall survival compared with patients with higher levels, regardless of treatment arm (hazard ratio [HR] = 0.60, P = .002). A similar correlation was observed for progression-free survival (HR = 0.69, P = .02). When examined as a continuous variable, OPN maintained its significant association with both progression-free (HR = 1.05, P = .01) and overall survival (HR = 1.09, P < .0001). Patients with lower plasma OPN levels were significantly more likely to have tumor response (P = .03). No differences were observed between treatment arms. Tumor OPN levels did not correlate with patient outcomes or with plasma levels. No associations were observed between patient outcomes and VEGF or PAI-1 levels; however, plasma concentrations of these markers were significantly interrelated (P < .0001) and significantly decreased after treatment (P = .0002 and P = .03, respectively).

CONCLUSION

Pretreatment plasma levels of OPN are significantly associated with patient response, progression-free survival, and overall survival in chemotherapy-treated patients with advanced NSCLC.

Clinical biomarkers for hypoxia targeting

Tumor hypoxia or a reduction of the tissue oxygen tension is a key microenvironmental factor for tumor progression and treatment resistance in solid tumors. Because hypoxic tumor cells have been demonstrated to be more resistant to ionizing radiation, hypoxia has been a focus of laboratory and clinical research in radiation therapy for many decades. It is believed that proper detection of hypoxic regions would guide treatment options and ultimately improve tumor response. To date, most clinical efforts in targeting tumor hypoxia have yielded equivocal results due to the lack of appropriate patient selection. However, with improved understanding of the molecular pathways regulated by hypoxia and the discovery of novel hypoxia markers, the prospect of targeting hypoxia has become more tangible. This chapter will focus on the development of clinical biomarkers for hypoxia targeting.

New developments in radiation therapy for head and neck cancer: intensity-modulated radiation therapy and hypoxia targeting

Intensity-modulated radiation therapy (IMRT) has revolutionized radiation treatment for head and neck cancers (HNCs). When compared to the traditional techniques, IMRT has the unique ability to minimize the dose delivered to normal tissues without compromising tumor coverage. As a result, side effects from high-dose radiation have decreased and patient quality of life has improved. In addition to toxicity reduction, excellent clinical outcomes have been reported for IMRT. The first part of this review will focus on clinical results of IMRT for HNC. Tumor hypoxia, or the condition of low oxygen, is a key factor for tumor progression and treatment resistance. Hypoxia develops in solid tumors due to aberrant blood vessel formation, fluctuation in blood flow, and increasing oxygen demands for tumor growth. Because hypoxic tumor cells are more resistant to ionizing radiation, hypoxia has been a focus of clinical research in radiation therapy for half a decade. Interest for targeting tumor hypoxia has waxed and waned as promising treatments emerged from the laboratory, only to fail in the clinics. However, with the development of new technologies, the prospect of targeting tumor hypoxia is more tangible. The second half of the review will focus on approaches for assessing tumor hypoxia and on the strategies for targeting this important microenvironmental factor in HNC.

New developments in radiation therapy for head and neck cancer: intensity-modulated radiation therapy and hypoxia targeting

Intensity-modulated radiation therapy (IMRT) has revolutionized radiation treatment for head and neck cancers (HNCs). When compared to the traditional techniques, IMRT has the unique ability to minimize the dose delivered to normal tissues without compromising tumor coverage. As a result, side effects from high-dose radiation have decreased and patient quality of life has improved. In addition to toxicity reduction, excellent clinical outcomes have been reported for IMRT. The first part of this review will focus on clinical results of IMRT for HNC. Tumor hypoxia, or the condition of low oxygen, is a key factor for tumor progression and treatment resistance. Hypoxia develops in solid tumors due to aberrant blood vessel formation, fluctuation in blood flow, and increasing oxygen demands for tumor growth. Because hypoxic tumor cells are more resistant to ionizing radiation, hypoxia has been a focus of clinical research in radiation therapy for half a decade. Interest for targeting tumor hypoxia has waxed and waned as promising treatments emerged from the laboratory, only to fail in the clinics. However, with the development of new technologies, the prospect of targeting tumor hypoxia is more tangible. The second half of the review will focus on approaches for assessing tumor hypoxia and on the strategies for targeting this important microenvironmental factor in HNC.

Small integrin-binding ligand N-linked glycoproteins (SIBLINGs): multifunctional proteins in cancer

Numerous components and pathways are involved in the complex interplay between cancer cells and their environment. The family of glycophosphoproteins comprising osteopontin, bone sialoprotein, dentin matrix protein 1, dentin sialophosphoprotein and matrix extracellular phosphoglycoprotein - small integrin-binding ligand N-linked glycoproteins (SIBLINGs) - are emerging as important players in many stages of cancer progression. From their detection in various human cancers to the demonstration of their key functional roles during malignant transformation, invasion and metastasis, the SIBLINGs are proteins with potential as diagnostic and prognostic tools, as well as new therapeutic targets.

Differential risk assessments from five hypoxia specific assays: The basis for biologically adapted individualized radiotherapy in advanced head and neck cancer patients

PURPOSE

Hypoxia adversely relates with prognosis in human tumours. Five hypoxia specific predictive marker assays were compared and correlated with definitive radiotherapy.

PATIENTS AND METHODS

Sixty-seven patients with advanced head and neck carcinomas were studied for pre-treatment plasma osteopontin measured by ELISA, tumour oxygenation status using pO(2) needle electrodes and tumour osteopontin, hypoxia inducible factor 1alpha (HIF-1alpha) and carboxyanhydrase 9 (CA9) by immunohistochemistry. The primary treatment was radiotherapy and the hypoxic radiosensitizer nimorazole. Loco-regional tumour control was evaluated at 5 years.

RESULTS

All five markers showed inter-tumour variability. Inter-marker correlations were inconsistent. Only plasma osteopontin inversely correlated with median tumour pO(2), (p=0.02, r=0.28) and CA9 correlated with HIF-1alpha (p<0.01, r=0.45). In Kaplan-Meier analysis high plasma osteopontin, high HIF-1alpha and high proportion of tumour pO(2)2.5mmHg (HP(2.5)) related significantly with poorer loco-regional control, whereas CA9 and tumour osteopontin failed to predict loco-regional control in this set dataset. When analyzing Hb, stage, and the five markers by competing risks HP(2.5) was the strongest variable to predict for loco-regional tumour control.

CONCLUSION

There was diversity and lack of correlation among five different hypoxia assays within individual tumours. High plasma osteopontin, high HIF-1alpha and high proportion of tumour pO(2)2.5mmHg (HP(2.5)) related significantly with poorer loco-regional control, whereas CA9 and tumour OPN failed to predict local control.

Hypoxia induced expression of endogenous markers in vitro is highly influenced by pH

BACKGROUND

Genes such as carbonic anhydrase IX (Ca9), glucose transporter 1 (Glut1), lactate dehydrogenase A (LDH-A), osteopontin (OPN) and lysyl oxidase (LOX) have been suggested as hypoxic markers, but inconsistent results suggest that factors other than oxygen influence their expression. The current study is a detailed investigation using a range of pH values from 6.3 to 7.5 in two human cell lines to establish the pH dependency of hypoxia induced gene expression.

METHODS

Human tumour cell lines (uterine cervix squamous cell carcinoma (SiHa) and pharyngeal squamous cell carcinoma [FaDu(DD)]) were used. Hypoxia was induced by gassing cells in airtight chambers with various oxygen concentrations (21%, 1%, 0.1%, 0.01% and 0%) for up to 24h. The media were titrated to a range of pH values (7.5, 7.0, 6.7, 6.5 and 6.3). Gene expression was determined by real-time PCR.

RESULTS

In both SiHa and FaDu(DD) cells Ca9 and LOX reached the highest level of expression at 1% oxygen. In FaDu(DD) cells, a pH of 6.5 had a medium suppression effect on the hypoxia induced expression of Ca9. pH 6.3 resulted in severe suppression of expression for Ca9 and LOX in both SiHa and FaDu(DD). Glut1 and LDH-A had a similar expression pattern to each other, with a maximum expression at 0.01% oxygen, in both cell lines. For these genes pH 6.5 and 6.3 changed the expression pattern in SiHa cells. OPN was up regulated at low oxygen in SiHa cells, but was not induced by hypoxia in FaDu(DD) cells.

CONCLUSION

As tumour hypoxia occurs in a deprived microenvironment, other environmental factors, for example low pH, might interact with the effect of low oxygen concentration on gene expression. This study shows that pH in two cell lines has a profound influence on the oxygen dependent induction of certain endogenous hypoxic markers.