An evaluation of tumor oxygenation and gene expression in patients with early stage non-small cell lung cancers

Prognostic Significance of Carbonic Anhydrase IX Expression in Cancer Patients: A Meta-Analysis

Hypoxia is a characteristic of many solid tumors and an adverse prognostic factor for treatment outcome. Hypoxia increases the expression of carbonic anhydrase IX (CAIX), an enzyme that is predominantly found on tumor cells and is involved in maintaining the cellular pH balance. Many clinical studies investigated the prognostic value of CAIX expression, but most have been inconclusive, partly due to small numbers of patients included. The present meta-analysis was therefore performed utilizing the results of all clinical studies to determine the prognostic value of CAIX expression in solid tumors. Renal cell carcinoma was excluded from this meta-analysis due to an alternative mechanism of upregulation. 958 papers were identified from a literature search performed in PubMed and Embase. These papers were independently evaluated by two reviewers and 147 studies were included in the analysis. The meta-analysis revealed strong significant associations between CAIX expression and all endpoints: overall survival [hazard ratio (HR) = 1.76, 95% confidence interval (95%CI) 1.58–1.98], disease-free survival (HR = 1.87, 95%CI 1.62–2.16), locoregional control (HR = 1.54, 95%CI 1.22–1.93), disease-specific survival (HR = 1.78, 95%CI 1.41–2.25), metastasis-free survival (HR = 1.82, 95%CI 1.33–2.50), and progression-free survival (HR = 1.58, 95%CI 1.27–1.96). Subgroup analyses revealed similar associations in the majority of tumor sites and types. In conclusion, these results show that patients having tumors with high CAIX expression have higher risk of locoregional failure, disease progression, and higher risk to develop metastases, independent of tumor type or site. The results of this meta-analysis further support the development of a clinical test to determine patient prognosis based on CAIX expression and may have important implications for the development of new treatment strategies.

Human Cells Cultured under Physiological Oxygen Utilize Two Cap-binding Proteins to recruit Distinct mRNAs for Translation

Translation initiation is a focal point of translational control and requires the binding of eIF4E to the 5' cap of mRNA. Under conditions of extreme oxygen depletion (hypoxia), human cells repress eIF4E and switch to an alternative cap-dependent translation mediated by a homolog of eIF4E, eIF4E2. This homolog forms a complex with the oxygen-regulated hypoxia-inducible factor 2α and can escape translation repression. This complex mediates cap-dependent translation under cell culture conditions of 1% oxygen (to mimic tumor microenvironments), whereas eIF4E mediates cap-dependent translation at 21% oxygen (ambient air). However, emerging evidence suggests that culturing cells in ambient air, or "normoxia," is far from physiological or "normal." In fact, oxygen in human tissues ranges from 1-11% or "physioxia." Here we show that two distinct modes of cap-dependent translation initiation are active during physioxia and act on separate pools of mRNAs. The oxygen-dependent activities of eIF4E and eIF4E2 are elucidated by observing their polysome association and the status of mammalian target of rapamycin complex 1 (eIF4E-dependent) or hypoxia-inducible factor 2α expression (eIF4E2-dependent). We have identified oxygen conditions where eIF4E is the dominant cap-binding protein (21% normoxia or standard cell culture conditions), where eIF4E2 is the dominant cap-binding protein (1% hypoxia or ischemic diseases and cancerous tumors), and where both cap-binding proteins act simultaneously to initiate the translation of distinct mRNAs (1-11% physioxia or during development and stem cell differentiation). These data suggest that the physioxic proteome is generated by initiating translation of mRNAs via two distinct but complementary cap-binding proteins.

Oxidative stress under ambient and physiological oxygen tension in tissue culture

Oxygen (O₂) levels range from 2-9% in vivo. However, cell culture experiments are performed at atmospheric O₂ levels (21%). Oxidative stress due to generation of reactive oxygen species (ROS) in cells cultured at higher than physiological levels is implicated in multitude of deleterious effects including DNA damage, genomic instability and senescence. In addition, oxidative stress activates redox sensitive transcription factors related to inflammatory signaling and apoptotic signaling. Furthermore, several chromatin-modifying enzymes are affected by ROS, potentially impacting epigenetic regulation of gene expression. While primary cells are cultured at lower O₂ levels due to their inability to grow at higher O₂, the immortalized cells, which display no such apparent growth difficulties, are typically cultured at 21% O₂. This review will provide an overview of issues associated with increased oxygen levels in in vitro cell culture and point out the benefits of using lower levels of oxygen tension even for immortalized cells.

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.

FMISO as a Biomarker for Clinical Radiation Oncology

Tumour hypoxia is a well-known negative prognostic marker in almost all solid tumours. [18F]Fluoromisonidazole (FMISO)-positron emission tomography (PET) is a non-invasive method to detect tumour hypoxia. Compared to other methods of hypoxia assessment it possesses some considerable advantages: It is non-invasive, it delivers spatial information on the hypoxia distribution within the entire tumour volume, and it can be repeated during the course of radio(chemo)therapy. This chapter briefly describes different methods of hypoxia evaluation and focuses on hypoxia PET imaging, with the most commonly used tracer being FMISO. The preclinical rationale and clinical studies to use FMISO-PET for patient stratification in radiation therapy are discussed as well as possible agents or radiation-dose modifications to overcome hypoxia.

The role of hypoxia in cancer progression, angiogenesis, metastasis, and resistance to therapy

Hypoxia is a non-physiological level of oxygen tension, a phenomenon common in a majority of malignant tumors. Tumor-hypoxia leads to advanced but dysfunctional vascularization and acquisition of epithelial-to-mesenchymal transition phenotype resulting in cell mobility and metastasis. Hypoxia alters cancer cell metabolism and contributes to therapy resistance by inducing cell quiescence. Hypoxia stimulates a complex cell signaling network in cancer cells, including the HIF, PI3K, MAPK, and NFĸB pathways, which interact with each other causing positive and negative feedback loops and enhancing or diminishing hypoxic effects. This review provides background knowledge on the role of tumor hypoxia and the role of the HIF cell signaling involved in tumor blood vessel formation, metastasis, and development of the resistance to therapy. Better understanding of the role of hypoxia in cancer progression will open new windows for the discovery of new therapeutics targeting hypoxic tumor cells and hypoxic microenvironment.

Nuclear Factor κB1/RelA Mediates Inflammation in Human Lung Epithelial Cells at Atmospheric Oxygen Levels

Oxygen levels range from 2% to 9% in vivo. Atmospheric O2 levels (21%) are known to induce cell proliferation defects and cellular senescence in primary cell cultures. However, the mechanistic basis of the deleterious effects of higher O2 levels is not fully understood. On the other hand, immortalized cells including cancer cell lines, which evade cellular senescence are normally cultured at 21% O2 and the effects of higher O2 on these cells are understudied. Here, we addressed this problem by culturing immortalized human bronchial epithelial (BEAS-2B) cells at ambient atmospheric, 21% O2 and lower, 10% O2. Our results show increased inflammatory response at 21% O2 but not at 10% O2. We found higher RelA binding at the NF-κB1/RelA target gene promoters as well as upregulation of several pro-inflammatory cytokines in cells cultured at 21% O2. RelA knockdown prevented the upregulation of the pro-inflammatory cytokines at 21% O2, suggesting NF-κB1/RelA as a major mediator of inflammatory response in cells cultured at 21% O2. Interestingly, unlike the 21% O2 cultured cells, exposure of 10% O2 cultured cells to H2O2 did not elicit inflammatory response, suggesting increased ability to tolerate oxidative stress in cells cultured at lower O2 levels.

Evaluation of hypoxia with copper-labeled diacetyl-bis(N-methylthiosemicarbazone)

Imaging of hypoxia is important in many diseases states in oncology, cardiology, and neurology. The radiopharmaceutical, copper-labeled diacetyl-bis(N-methylthiosemicarbazone), has been used to assess hypoxia in many studies. In particular, copper-labeled diacetyl-bis(N-methylthiosemicarbazone) has been used in oncologic settings to investigate tumor hypoxia and the role of this parameter in response to therapy and outcome. Some groups have conducted imaging studies assessing the role of hypoxia in cardiovascular and neurologic disorders. Additionally, several groups have made significant progress into understanding the mechanism by which this compound accumulates in cells. Multiple preclinical and clinical studies have been conducted, shedding light on the importance of careful image analysis when using this tracer. This review article focuses on the recent preclinical and clinical studies with this tracer.

The immunological effect of hyaluronan in tumor angiogenesis

The relationship between the immune system and angiogenesis has been described in several contexts, both in physiological and pathological conditions, as pregnancy and cancer. In fact, different types of immune cells, such as myeloid, macrophages and denditric cells, are able to modulate tumor neovascularization. On the other hand, tumor microenvironment also includes extracellular matrix components like hyaluronan, which has a deregulated synthesis in different tumors. Hyaluronan is a glycosaminoglycan, normally present in the extracellular matrix of tissues in continuous remodeling (embryogenesis or wound healing processes) and acts as an important modulator of cell behavior by different mechanisms, including angiogenesis. In this review, we discuss hyaluronan as a modulator of tumor angiogenesis, focusing in intracellular signaling mediated by its receptors expressed on different immune cells. Recent observations suggest that the immune system is an important component in tumoural angiogenesis. Therefore, immune modulation could have an impact in anti-angiogenic therapy as a new therapeutic strategy, which in turn might improve effectiveness of treatment in cancer patients.

Prognostic significance of hypoxic PET using (18)F-FAZA and (62)Cu-ATSM in non-small-cell lung cancer

OBJECTIVES

Tumor hypoxia is believed to have a strong correlation with the resistance to chemoradiotherapy. Noninvasive evaluation of hypoxic status in tumors using molecular imaging has the potential to characterize the tumor aggressiveness. We evaluated the clinical usefulness of newly-developed tumor hypoxic positron emission tomography (PET) tracers in localized non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Forty-seven patients with localized NSCLC received either or both hypoxic PETs using the tracers: (18)F-fluoroazomycin arabinoside ((18)F-FAZA) (n=45) and/or (62)Cu-diacetyl-bis (N4)-methylsemithiocarbazone ((62)Cu-ATSM) (n=22). All received (18)F-fluorodeoxyglucose ((18)F-FDG) PET tracer (n=47). We examined the correlation between uptake of three PET tracers and clinicopathological factors, and evaluated their impacts on survival after treatment retrospectively.

RESULTS

A couple of commonly-identified unfavorable factors such as presence of vascular invasion and pleural invasion was significantly correlated with higher uptake of these hypoxic agents as well as that of (18)F-FDG. Larger tumor diameter, high neutrophil-to-lymphocyte ratio and advanced pathological stage were also associated with accumulation of hypoxic PETs ((18)F-FAZA, p<0.01; (62)Cu-ATSM, p<0.04), but not with that of (18)F-FDG. The patients with a higher accumulation had significantly poorer overall survival [(18)F-FAZA, HR (hazard ratio), 9.50, p<0.01; (62)Cu-ATSM, HR, 4.06, p<0.05] and progression free survival ((18)F-FAZA, HR, 5.28, p<0.01, (62)Cu-ATSM, HR, 2.72, p<0.05).

CONCLUSION

Both (18)F-FAZA and (62)Cu-ATSM PET provide useful information regarding tumor aggressiveness and prediction of survival among NSCLC patients. We believe these hypoxic PETs could contribute to the establishment of the optimally individualized treatment of NSCLC.

The association between osteopontin and survival in non-small-cell lung cancer patients: a meta-analysis of 13 cohorts

In the last decade, osteopontin (OPN) was identified as one of the important proteins that promote the metastasis of tumor. However, the association between OPN overexpression and clinical outcome of non-small-cell lung cancer (NSCLC) was unclear. The purpose of this study is to investigate the role of OPN in NSCLC patients. A total of 13 studies are included to explore the relationship between the OPN elevation and the overall survival (OS) and disease-free survival (DFS) in NSCLC patients. We searched for related articles in PubMed, Web of Science, Google Scholar, and Cochrane Library databases, which were published before January 31, 2015. Hazard ratio (HR), odds ratio (OR), and 95% confidence interval (CI) in the high OPN expression group compared with the low OPN expression group were calculated and analyzed. Primary results were summarized by using a fixed-effects model or a random-effects model. The stratified analyses in subgroups were also performed. Thirteen cohort studies, which involved 1,630 patients, were included. Subgroup analyses were performed by area and test method of OPN. We found that OPN was significantly associated with poor OS (HR =2.20, 95% CI 1.71–2.83, P<0.001) and DFS (HR =2.11, 95% CI 1.62–2.74, P<0.001) in NSCLC patients. OPN overexpression tended to be associated with the presence of advanced tumor TNM stage (III and IV) (OR =2.57, 95% CI 1.61–4.11, P<0.001). The Egger’s test suggested that there was no publication bias in OS studies (P=0.062) and DFS studies (P=0.740). These data indicate that OPN seems to have a significant predictive potential in estimating survival in NSCLC.

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.

Molecular imaging of hypoxia in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is the commonest cancer worldwide but survival remains poor with a high risk of relapse, particularly after nonsurgical treatment. Hypoxia is present in a variety of solid tumours, including NSCLC. It is associated with treatment resistance and a poor prognosis, although when recognised may be amenable to different treatment strategies. Thus, noninvasive assessment of intratumoral hypoxia could be used to stratify patients for modification of subsequent treatment to improve tumour control. Molecular imaging approaches targeting hypoxic cells have shown some early success in the clinical setting. This review evaluates the evidence for hypoxia imaging using PET in NSCLC and explores its potential clinical utility.

Nutrient stress revamps cancer cell metabolism

Efforts to identify new therapeutic targets in cancer primarily focused on oncogenes and tumor suppressor genes, and their mechanisms of action. However, there is an emerging alternative strategy that involves identification of target proteins that are not encoded by oncogenes, but are, nonetheless, required to accommodate cancer-specific stresses.

Prognostic significance of osteopontin expression in non-small-cell lung cancer: A meta-analysis

Osteopontin (OPN) plays an important role in the progression and metastasis of cancer. However, the role of OPN as a prognostic factor in non-small-cell lung cancer (NSCLC) remains controversial. The aim of this study was to investigate the association between OPN expression and prognosis in patients with NSCLC using a meta-analysis. Based on PubMed, Ovid Medline, Embase, ISI, ScienceDirect and SpringerLink databases, related articles published prior to January, 2013 were collected. A meta-analysis was conducted to investigate the association of OPN expression with overall survival (OS) and progression-free survival (PFS) in patients with NSCLC. Hazard ratio (HR) with 95% confidence interval (CI) was used to assess the strength of this association. A total of 6 studies, including 776 patients, were found to be eligible for the meta-analysis. No heterogeneity was observed in OS or PFS, whereas low OPN expression was found to be correlated with better OS (HR=0.57, 95% CI: 0.46-0.70) and PFS (HR=0.62, 95% CI: 0.49-0.77). This meta-analysis demonstrated an association of OPN with poor prognosis in NSCLC patients. However, prospective studies are required to confirm these findings.

Membrane carbonic anhydrase IX expression and relapse risk in resected stage I-II non-small-cell lung cancer

BACKGROUND

Adjuvant chemotherapy reduces recurrences of non-small-cell lung cancer (NSCLC). To determine which patients need adjuvant chemotherapy, we assessed factors associated with time to relapse (TTR).

METHODS

In 230 resected stage I-II NSCLCs, we correlated immunohistochemistry scores for factors associated with cell growth rate, growth regulation, hypoxia, cell survival, and cell death with TTR.

RESULTS

With a median follow-up of 82 months (1-158) for those alive and relapse free at last follow-up, median time to recurrence was not reached. The 2- and 5-year probabilities of maintaining freedom from recurrence were 80.7% (95% confidence interval, 75.3%, 86.4%) and 74.6% (95% confidence interval, 68.6%, 81.2%), respectively. TTR curves flattened at an apparent cure rate of 70%. In multicovariate Cox models, factors correlating with shorter TTR were membranous carbonic anhydrase IX (mCAIX) staining (any versus none, hazard ratio = 2.083, p = 0.023) and node stage (N1 versus N0, hazard ratio = 2.591, p = 0.002). mCAIX scores correlated positively with tumor size, grade, squamous histology, necrosis, mitoses, Ki67, p53, nuclear DNA methyltransferase 1, and cytoplasmic enhancer-of-split-and-hairy-related protein, and they correlated inversely with papillary histology, epidermal growth factor receptor mutation (trend), copper transporter-1, and cytoplasmic hypoxia-inducible factor-1α, vascular endothelial growth factor, DNA methyltransferase 1, and excision repair cross-complementing rodent repair deficiency, complementation group 1.

CONCLUSION

Nodal stage and mCAIX immunohistochemistry were the strongest independent predictors of shorter TTR in resected NSCLCs. mCAIX correlated with tumor size, markers of tumor proliferation and necrosis, and tumor genetic characteristics, and it paradoxically correlated inversely with the hypoxia markers, hypoxia-inducible factor-1α and vascular endothelial growth factor. Presence of mCAIX could help determine patients with high risk of recurrence who might require adjuvant chemotherapy.

Positron emission tomography to assess hypoxia and perfusion in lung cancer

In lung cancer, tumor hypoxia is a characteristic feature, which is associated with a poor prognosis and resistance to both radiation therapy and chemotherapy. As the development of tumor hypoxia is associated with decreased perfusion, perfusion measurements provide more insight into the relation between hypoxia and perfusion in malignant tumors. Positron emission tomography (PET) is a highly sensitive nuclear imaging technique that is suited for non-invasive in vivo monitoring of dynamic processes including hypoxia and its associated parameter perfusion. The PET technique enables quantitative assessment of hypoxia and perfusion in tumors. To this end, consecutive PET scans can be performed in one scan session. Using different hypoxia tracers, PET imaging may provide insight into the prognostic significance of hypoxia and perfusion in lung cancer. In addition, PET studies may play an important role in various stages of personalized medicine, as these may help to select patients for specific treatments including radiation therapy, hypoxia modifying therapies, and antiangiogenic strategies. In addition, specific PET tracers can be applied for monitoring therapy. The present review provides an overview of the clinical applications of PET to measure hypoxia and perfusion in lung cancer. Available PET tracers and their characteristics as well as the applications of combined hypoxia and perfusion PET imaging are discussed.

Hypoxia as a cause of treatment failure in non-small cell carcinoma of the lung

Hypoxia is an important factor in tumor biology and is both a predictive and a prognostic factor in non-small cell lung cancer. The negative effect of low oxygenation on radiation therapy effect has been known for decades, but more recent research has emphasized that hypoxia also has a profound effect on a tumor's aggression and metastatic propensity. In this review, current knowledge on both these aspects of treatment failure in NSCLC due to hypoxia has been discussed, along with a presentation of modern methods for hypoxia measurement and current therapeutical interventions to circumvent the negative effect of hypoxia on treatment results.

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.

The clinical importance of assessing tumor hypoxia: relationship of tumor hypoxia to prognosis and therapeutic opportunities

Tumor hypoxia is a well-established biological phenomenon that affects the curability of solid tumors, regardless of treatment modality. Especially for head and neck cancer patients, tumor hypoxia is linked to poor patient outcomes. Given the biological problems associated with tumor hypoxia, the goal for clinicians has been to identify moderately to severely hypoxic tumors for differential treatment strategies. The "gold standard" for detecting and characterizing of tumor hypoxia are the invasive polarographic electrodes. Several less invasive hypoxia assessment techniques have also shown promise for hypoxia assessment. The widespread incorporation of hypoxia information in clinical tumor assessment is severely impeded by several factors, including regulatory hurdles and unclear correlation with potential treatment decisions. There is now an acute need for approved diagnostic technologies for determining the hypoxia status of cancer lesions, as it would enable clinical development of personalized, hypoxia-based therapies, which will ultimately improve outcomes. A number of different techniques for assessing tumor hypoxia have evolved to replace polarographic pO2 measurements for assessing tumor hypoxia. Several of these modalities, either individually or in combination with other imaging techniques, provide functional and physiological information of tumor hypoxia that can significantly improve the course of treatment. The assessment of tumor hypoxia will be valuable to radiation oncologists, surgeons, and biotechnology and pharmaceutical companies who are engaged in developing hypoxia-based therapies or treatment strategies.

Hypoxia-induced carbonic anhydrase IX as a target for cancer therapy: from biology to clinical use

The tumor microenvironment includes a complicated network of physiological gradients contributing to plasticity of tumor cells and heterogeneity of tumor tissue. Hypoxia is a key component generating intratumoral oxygen gradients, which affect the cellular expression program and lead to therapy resistance and increased metastatic propensity of weakly oxygenated cell subpopulations. One of the adaptive responses of tumor cells to hypoxia involves the increased expression and functional activation of carbonic anhydrase IX (CA IX), a cancer-related cell surface enzyme catalyzing the reversible conversion of carbon dioxide to bicarbonate ion and proton. Via its catalytic activity, CA IX participates in regulation of intracellular and extracellular pH perturbations that result from hypoxia-induced changes in cellular metabolism producing excess of acid. Through the ability to regulate pH, CA IX also facilitates cell migration and invasion. In addition, CA IX has non-catalytic function in cell adhesion and spreading. Thus, CA IX endows tumor cells with survival advantages in hypoxia/acidosis and confers an increased ability to migrate, invade and metastasize. Accordingly, CA IX is expressed in a broad range of tumors, where it is associated with prognosis and therapy outcome. Its expression pattern and functional implications in tumor biology make CA IX a promising therapeutic target, which can be hit either by immunotherapy with monoclonal antibodies or with compounds inhibiting its enzyme activity. The first strategy has already reached the clinical trials, whereas the second one is still in preclinical testing. Both strategies indicate that CA IX can become a clinically useful anticancer target, but urge further efforts toward better selection of patients for immunotherapy and deeper understanding of tumor types, clinical situations and synthetic lethality interactions with other treatment approaches.

Hypoxia-induced angiogenesis is increased by the controlled release of deferoxiamine from gelatin hydrogels

The objective of this study is to design biodegradable hydrogels for the controlled release of deferoxiamine (DFO) and evaluate their biological activity. When the DFO was added to human umbilical vein endothelial cells cultured in 5.0% O2, the level of hypoxia-inducible factor-1α and vascular endothelial growth factor significantly increased compared with that without DFO. The expression of angiogenesis-related genes was accordingly increased by the DFO addition. An aqueous solution of mixed gelatin and DFO was freeze-dried, and dehydrothermally treated at 140°C for 24h to prepare a gelatin hydrogel incorporating DFO. In the release test with phosphate-buffered saline solution (PBS) at 37°C, an initial DFO release of 60% was observed, followed by no release. When placed in PBS containing collagenase, the hydrogel was enzymatically degraded with time, and consequently released DFO in a degradation-dependent manner. After the hydrogel incorporating DFO was injected intramuscularly into a mouse model of hind limb ischemia, the number of new blood vessels formed was significantly higher than that with free DFO and DFO-free hydrogel. It is concluded that the DFO-containing hydrogel shows promising for inducing angiogenesis locally.

Carbonic anhydrase IX-directed immunoliposomes for targeted drug delivery to human lung cancer cells in vitro

Targeted drug delivery to cancer cells by use of antibody-conjugated liposomes (immunoliposomes) has attracted considerable interest in recent years. Despite increasing efforts in developing immunoliposomes as drug carriers, the investigation of useful tumor-associated antigen targets is far from complete. Carbonic anhydrase IX (CA IX) is a cell surface antigen characterized by hypoxia-induced expression in many solid tumors. This study investigated the feasibility of CA IX-directed immunoliposomes for targeted delivery of docetaxel to human lung cancer cells in vitro. Docetaxel-loaded immunoliposomes targeting CA IX were developed with an encapsulation efficiency of 84.4±3.9% and an average particle size of 143.9±11.1 nm. Using fluorescence-based flow cytometry, the in vitro binding activity of the immunoliposomes was found to be significantly higher (by 1.65-fold) than that of the nontargeted liposomes in CA IX-positive lung cancer cells, whereas no such difference was observed between the two groups when CA IX was not expressed. Furthermore, immunoliposomal docetaxel exhibited the strongest growth inhibitory effect against CA IX-positive lung cancer cells when compared with nontargeted liposomal docetaxel or free docetaxel solution. These data suggested that CA IX-directed immunoliposomes could serve as a promising drug delivery system for targeted killing of lung cancer cells.

Defining normoxia, physoxia and hypoxia in tumours-implications for treatment response

Tumour hypoxia is increasingly recognized as a major deleterious factor in cancer therapies, as it compromises treatment and drives malignant progression. This review seeks to clarify the oxygen levels that are pertinent to this issue. It is argued that normoxia (20% oxygen) is an extremely poor comparator for "physoxia", i.e. the much lower levels of oxygen universally found in normal tissues, which averages about 5% oxygen, and ranges from about 3% to 7.4%. Importantly, it should be recognized that the median oxygenation in untreated tumours is significantly much lower, falling between approximately 0.3% and 4.2% oxygen, with most tumours exhibiting median oxygen levels <2%. This is partially dependent on the tissue of origin, and it is notable that many prostate and pancreatic tumours are profoundly hypoxic. In addition, therapy can induce even further, often unrecognized, changes in tumour oxygenation that may vary longitudinally, increasing or decreasing during treatment in ways that are not always predictable. Studies that fail to take cognizance of the actual physiological levels of oxygen in tissues (approximately 5%) and tumours (approximately 1%) may fail to identify the real circumstances driving tumour response to treatment and/or malignant progression. This can be of particular importance in genetic studies in vitro when comparison to human tumours is required.

Prognostic value of CD44 and CD44v6 expression in patients with non-small cell lung cancer: meta-analysis

We sought to clarify the prognostic value of CD44 in survival of patients with non-small cell lung cancer (NSCLC). We performed a meta-analysis of relevant literature to aggregate the available survival results, using studies published in English until March 2014. Eligible studies dealt with CD44, CD44 standard form (CD44s) and CD44 variant 6 (CD44v6), assessment in NSCLC patients on primary lesions and reported survival data according to CD44 and CD44 isoforms expression. We aggregated 10 trials (5 trials for CD44v6, 3 trials for CD44, and 2 trials for CD44s) comprising 1,074 patients, in this meta-analysis. The combined hazard ratio (HR) with CD44v6 and CD44s was 2.39 (95 % confidence interval (CI) 1.69-3.37) and 1.64 (95 % CI 1.06-2.52), respectively. It associated high CD44v6 and CD44s expression with poor survival in NSCLC patients. However, CD44 overexpression did not significantly correlate with survival in patients with NSCLC (HR 1.44; 95 % CI 0.72-2.89). Our meta-analysis shows that CD44v6 and CD44s overexpression indicates poor prognosis for NSCLC patients. However, the high CD44 expression is not significantly correlated with survival for patients with NSCLC.

The meaning, measurement and modification of hypoxia in the laboratory and the clinic

Hypoxia was identified as a microenvironmental component of solid tumours over 60 years ago and was immediately recognised as a potential barrier to therapy through the reliance of radiotherapy on oxygen to elicit maximal cytotoxicity. Over the last two decades both clinical and experimental studies have markedly enhanced our understanding of how hypoxia influences cellular behaviour and therapy response. Furthermore, they have confirmed early assumptions that low oxygenation status in tumours is an exploitable target in cancer therapy. Generally such approaches will be more beneficial to patients with hypoxic tumours, necessitating the use of biomarkers that reflect oxygenation status. Tissue biomarkers have shown utility in many studies. Further significant advances have been made in the non-invasive measurement of tumour hypoxia with positron emission tomography, magnetic resonance imaging and other imaging modalities. Here, we describe the complexities of defining and measuring tumour hypoxia and highlight the therapeutic approaches to combat it.

Hypoxia imaging with 18F-fluoroerythronitroimidazole integrated PET/CT and immunohistochemical studies in non-small cell lung cancer

PURPOSE

(18)F-fluoroerythronitroimidazole ((18)F-FETNIM) PET/CT allows a noninvasive assessment of tumor hypoxia. The purpose of this study was to evaluate a noninvasive and simplicity parameter for quantization of (18)F-FETNIM uptake with expectations to predict survival in non-small cell lung cancer surgical patients and investigate the relationship between (18)F-FETNIM uptake and molecular markers related to hypoxia, glucose metabolism, and angiogenesis.

PATIENTS AND METHODS

Thirty-two patients with biopsy-proven non-small cell lung cancer for surgical treatment were enrolled from March 2007 to February 2011. All patients had PET/CT studies with (18)F-FETNIM and subsequently underwent surgery. Twenty-five patients had stage II disease of surgical staging only for statistical analysis. The tumor-to-mediastinum (T/Me) ratio was calculated and correlated with survival and immunohistochemical staining of hypoxia inducible factor 1α (HIF-1α), glucose transporter 1 (GLUT-1), and vascular endothelial growth factor (VEGF).

RESULTS

The actuarial survival was worse for patients showing a high T/Me ratio, the best discriminative cutoff value being 1.9. A statistically significant worse survival was noted in patients having a tumor with a T/Me ratio of 1.9 or greater, compared with patients showing a tumor with a T/Me ratio of less than 1.9, a 3-year survival of 43.8% and 88.9%, respectively (P = 0.034). There was a positive correlation between T/Me ratio and HIF-1α (P = 0.023), GLUT-1 (P = 0.035), and VEGF (P = 0.042).

CONCLUSIONS

T/Me ratio provides a noninvasive parameter for quantization of (18)F-FETNIM uptake on PET/CT. T/Me ratio is correlated with a worse outcome and with the expression of HIF-1α, GLUT-1, and VEGF, all up-regulated under hypoxic conditions.

Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model - role of tumor stroma cells

Background

Hypoxia-induced genes are potential targets in cancer therapy. Responses to hypoxia have been extensively studied in vitro, however, they may differ in vivo due to the specific tumor microenvironment. In this study gene expression profiles were obtained from fresh human lung cancer tissue fragments cultured ex vivo under different oxygen concentrations in order to study responses to hypoxia in a model that mimics human lung cancer in vivo.

Methods

Non-small cell lung cancer (NSCLC) fragments from altogether 70 patients were maintained ex vivo in normoxia or hypoxia in short-term culture. Viability, apoptosis rates and tissue hypoxia were assessed. Gene expression profiles were studied using Affymetrix GeneChip 1.0 ST microarrays.

Results

Apoptosis rates were comparable in normoxia and hypoxia despite different oxygenation levels, suggesting adaptation of tumor cells to hypoxia. Gene expression profiles in hypoxic compared to normoxic fragments largely overlapped with published hypoxia-signatures. While most of these genes were up-regulated by hypoxia also in NSCLC cell lines, membrane metallo-endopeptidase (MME, neprilysin, CD10) expression was not increased in hypoxia in NSCLC cell lines, but in carcinoma-associated fibroblasts isolated from non-small cell lung cancers. High MME expression was significantly associated with poor overall survival in 342 NSCLC patients in a meta-analysis of published microarray datasets.

Conclusions

The novel ex vivo model allowed for the first time to analyze hypoxia-regulated gene expression in preserved human lung cancer tissue. Gene expression profiles in human hypoxic lung cancer tissue overlapped with hypoxia-signatures from cancer cell lines, however, the elastase MME was identified as a novel hypoxia-induced gene in lung cancer. Due to the lack of hypoxia effects on MME expression in NSCLC cell lines in contrast to carcinoma-associated fibroblasts, a direct up-regulation of stroma fibroblast MME expression under hypoxia might contribute to enhanced aggressiveness of hypoxic cancers.

A pilot study on potential plasma hypoxia markers in the radiotherapy of non-small cell lung cancer. Osteopontin, carbonic anhydrase IX and vascular endothelial growth factor

BACKGROUND

Hypoxic radioresistance plays a critical role in the radiotherapy of cancer and adversely impacts prognosis and treatment response. This prospective study investigated the interrelationship and the prognostic significance of several hypoxia-related proteins in non-small cell lung cancer (NSCLC) patients treated by radiotherapy ± chemotherapy.

MATERIAL AND METHODS

Pretreatment osteopontin (OPN), vascular endothelial growth factor (VEGF) and carbonic anhydrase IX (CA IX) plasma levels were determined by ELISA in 55 NSCLC (M0) patients receiving 66 Gy curative-intent radiotherapy or chemoradiation. Marker correlation, association with clinicopathological parameters and the prognostic value of a biomarker combination was evaluated.

RESULTS

All biomarkers were linearly correlated and linked to different clinical parameters including lung function, weight loss (OPN), gross tumor volume (VEGF) and T stage (CA IX). High OPN (p = 0.03), VEGF (p = 0.02) and CA IX (p = 0.04) values were significantly associated with poor survival. Double marker combination additively increased the risk of death by a factor of 2 and high plasma levels of the triple combination OPN/VEGF/CA IX yielded a 5.9-fold risk of death (p = 0.009). The combined assessment of OPN/VEGF/CA IX correlated independently with prognosis (p = 0.03) in a multivariate Cox regression model including N stage, T stage and GTV.

CONCLUSION

This pilot study suggests that a co-detection augments the prognostic value of single markers and that the integration of OPN, VEGF and CA IX into a hypoxic biomarker profile for the identification of patients with largely hypoxic and radioresistant tumors should be further evaluated.

[Advances of hypoxia and lung cancer]

肺癌是我国发病率和死亡率增长最快, 对人群健康和生命威胁最大的恶性肿瘤, 其发生发展机制尚未完全清楚。肿瘤的低氧微环境发现于1955年, 而肺癌组织低氧直至2006年才被成功检测到。随着研究的深入, 低氧对肺癌的影响不仅限于对放疗的抵抗作用, 而且还会通过一个重要的促癌分子低氧诱导因子(hypoxia inducible factor, HIF)以及其调节蛋白脯氨酸羟化酶(prolyl hydroxylase domain, PHD)和希佩尔•林道病基因产物(product of von Hippel-Lindau gene, pVHL)对肺癌的发生发展、侵袭转移、化疗耐药以及预后等产生重要的调节作用。因此, 低氧、HIF、PHD和pVHL必将成为十分有潜力的肺癌治疗靶点。

Plasma osteopontin is a useful diagnostic biomarker for advanced non-small cell lung cancer

Background

Osteopontin (OPN) and carbonic anhydrase IX (CAIX), which are expressed on the surface of tumor cells, are associated with hypoxia during tumor development and progression. However, the roles of these proteins in the plasma of patients with non-small cell lung cancer (NSCLC) are poorly understood. Herein, we hypothesized that plasma OPN and CAIX levels could be used as diagnostic and prognostic tumor markers in patients with NSCLC.

Methods

Fifty-three patients with NSCLC and 50 healthy control subjects were enrolled. We selected controls without malignancy and matched them with NSCLC patient cases according to age and gender. Blood samples were collected at the time of diagnosis; the plasma levels of OPN and CAIX were measured by enzyme-linked immunosorbent assays.

Results

The plasma levels of OPN in the patients with NSCLC were significantly elevated as compared to those in the controls (p=0.016). However, there was no difference in the plasma level of CAIX between the NSCLC patients and controls. NSCLC patients with a distant metastasis had a remarkable increase in plasma OPN compared with patients without metastasis (p=0.026), but no such correlation was found for CAIX. There was no difference in overall survival rates according to the plasma level of OPN between the two groups (by Kaplan-Meier survival analysis).

Conclusion

Plasma OPN levels were elevated in patients with NSCLC as compared with the controls, with greater elevation of OPN levels in the advanced stages of disease. Therefore, plasma OPN may have utility as a diagnostic, but not prognostic, biomarker of advanced NSCLC.

Plasma osteopontin velocity differentiates lung cancers from controls in a CT screening population

INTRODUCTION

As CT screening is integrated into non-small cell lung cancer (NSCLC) care, additional parameters are needed to help distinguish cancers from benign nodules. Osteopontin (OPN), a secreted phosphoprotein, has elevated plasma levels in NSCLC. We hypothesize that changes in plasma OPN over time (i.e., OPN velocity [OPNV]) can differentiate NSCLC patients from those without cancer in a CT screening population.

METHODS

A nested case-control study was conducted within a NSCLC CT screening trial. Incident cancers with serial plasma were matched to controls. OPN was measured by ELISA. Demographic, OPN, and OPNV were compared between cancers and controls using Wilcoxon Signed Rank tests.

RESULTS

Ten incident cancers were identified. The pack years distributions were similar, but cancers were older (median of the paired difference: 5.35 years; p=0.002) and their surveillance intervals were shorter (median of the paired difference: -2 months; p=0. 03) than matched controls. Baseline OPN was similar (median of the paired difference: -5.15 ng/ml, p=0.50), but OPNV in the cancers was significantly greater than that of matched controls, (median of the paired difference: 1.06 ng/ml/month, p=0.01). Accuracy rate for prediction of disease status based on OPNV (adjusted for age and surveillance) was 83%.

CONCLUSIONS

These are early evidence for utility of monitoring plasma OPN during CT screening to assist in identification of NSCLCs.

Imaging of hypoxia with 18F-FAZA PET in patients with locally advanced non-small cell lung cancer treated with definitive chemoradiotherapy

INTRODUCTION

For many cancers, tumour hypoxia is an adverse prognostic factor, and increases chemoradiation resistance; its importance in non-small cell lung cancer (NSCLC) is unproven. This study evaluated tumoural hypoxia using fluoroazomycin arabinoside ((18) F-FAZA) positron emission tomography (PET) scans among patients with locoregionally advanced NSCLC treated with definitive chemoradiation.

METHODS

Patients with stage IIIA-IIIB NSCLC underwent (18) F-FAZA PET scans and (18) F-2-deoxyglucose (FDG)-PET scans within 4 weeks of commencing and 8 weeks following conventionally-fractionated concurrent platinum-based chemoradiation (60 Gy). Intra-lesional hypoxic volumes of the primary and nodal masses were compared with FDG-PET metabolic volumes. Baseline tumoural hypoxia was correlated with disease free survival (DFS).

RESULTS

Seventeen patients underwent pre-treatment (18) F-FAZA PET and FDG-PET scans. Intra-lesional hypoxia was identified on 11 scans (65%). Baseline lesional hypoxic volumes were consistently smaller than FDG-PET volumes (P = 0.012). There was no statistical difference between the mean FDG-PET volumes in patients with or without baseline hypoxia (P = 0.38). Eight patients with baseline hypoxia had post treatment (18) F-FAZA scans and 6 of these (75%) had resolution of imageable hypoxia following chemoradiation. The DFS was not significantly different between the hypoxic or non-hypoxic groups (median 0.8 years and 1.3 years respectively, P = 0.42).

CONCLUSIONS

Intra-lesional hypoxia, as detected by (18) F-FAZA PET, was present in 65% of patients with locally-advanced NSCLC and resolved in the majority of patients following chemoradiation. Larger studies are required to evaluate the prognostic significance of the presence and resolution of hypoxia assessed by PET in NSCLC.

Control of nutrient stress-induced metabolic reprogramming by PKCζ in tumorigenesis

Tumor cells have high-energetic and anabolic needs and are known to adapt their metabolism to be able to survive and keep proliferating under conditions of nutrient stress. We show that PKCζ deficiency promotes the plasticity necessary for cancer cells to reprogram their metabolism to utilize glutamine through the serine biosynthetic pathway in the absence of glucose. PKCζ represses the expression of two key enzymes of the pathway, PHGDH and PSAT1, and phosphorylates PHGDH at key residues to inhibit its enzymatic activity. Interestingly, the loss of PKCζ in mice results in enhanced intestinal tumorigenesis and increased levels of these two metabolic enzymes, whereas patients with low levels of PKCζ have a poor prognosis. Furthermore, PKCζ and caspase-3 activities are correlated with PHGDH levels in human intestinal tumors. Taken together, this demonstrates that PKCζ is a critical metabolic tumor suppressor in mouse and human cancer.

Elevated circulating levels of osteopontin are associated with metastasis in advanced non-small cell lung cancer

OBJECTIVE

To investigate the relationship between postoperative metastasis and circulating levels of osteopontin in non-small cell lung cancer (NSCLC).

METHODS

The expression of osteopontin mRNA were detected with RT-PCR technique. The circulating levels of osteopontin were measured through ELASA in 46 NSCLC cases that had not been received any anti-cancer treatment at the time of sampling. The tissues from fifteen patients with benign pulmonary diseases were studied as control group.

RESULTS

The overall median mRNA expression level of osteopontin was approximately 70-fold higher in tumor tissues than in matched normal lung tissues (P<0.001). Over-expression of osteopontin mRNA was significantly associated with clinical stage (P=0.009). Advanced disease states had higher circulating level of osteopontin (stage I+II versus stage III+VI). In multivariate analysis, stage was the only independent factor influencing circulating levels of osteopontin. All patients were followed up for 12 months, 2 of the 46 patients with both osteopontin mRNA expression and elevated plasma osteopontin levels had local recurrence and 10 had distant metastasis. There was a significant difference in the osteopontin levels between metastasis group and non-metastasis group.

CONCLUSION

Preoperative plasma levels of osteopontin are significantly associated with post-operative metastasis in advanced NSCLC.

All-thermoplastic nanoplasmonic microfluidic device for transmission SPR biosensing

Early and accurate disease diagnosis still remains a major challenge in clinical settings. Biomarkers could potentially provide useful tools for the detection and monitoring of disease progression, treatment safety and efficacy. Recent years have witnessed prodigious advancement in biosensor development with research directed towards rapid, real-time, label-free and sensitive biomarker detection. Among emerging techniques, nanoplasmonic biosensors pose tremendous potential to accelerate clinical diagnosis with real-time multiplexed analysis, rapid and miniaturized assays, low sample consumption and high sensitivity. In order to translate these technologies from the proof-of-principle concept level to point of care clinical diagnosis, integrated, portable devices having small footprint cartridges that house low-cost disposable consumables are sought. Towards this goal, we developed an all-polymeric nanoplasmonic microfluidic (NMF) transmission surface plasmon resonance (SPR) biosensor. The device was fabricated in thermoplastics using a simple, single step and cost-effective hot embossing technique amenable to mass production. The novel 3D hierarchical mold fabrication process enabled monolithic integration of blazed nanogratings within the detection chambers of a multichannel microfluidic system. Consequently, a single hard thermoplastic bottom substrate comprising plasmonic and fluidic features allowed integration of active fluidic elements, such as pneumatic valves, in the top soft thermoplastic cover, increasing device functionality. A simple and compact transmission-based optical setup was employed with multiplexed end-point or dual-channel kinetic detection capability which did not require stringent angular accuracy. The sensitivity, specificity and reproducibility of the transmission SPR biosensor was demonstrated through label-free immunodetection of soluble cell-surface glycoprotein sCD44 at clinically relevant picomolar to nanomolar concentrations.

18F-fluoromisonidazole PET/CT: a potential tool for predicting primary endocrine therapy resistance in breast cancer

Although endocrine therapy is an effective method to treat estrogen receptor (ER)-positive breast cancer, approximately 30%-40% of all hormone receptor-positive tumors display de novo resistance. The aim of our current study was to analyze whether (18)F-labeled fluoromisonidazole (1-(2-nitro-1-imidazolyl)-2-hydroxy-3-fluoropropane [(18)F-FMISO]) PET/CT could predict primary resistance to hormonal therapy in ER-positive breast cancer.

METHODS

Postmenopausal women who had ER-α-positive breast cancer, stages II-IV, and had never received prior endocrine therapy were prospectively enrolled in this study. Patients underwent both (18)F-FDG and (18)F-FMISO PET/CT scans before and after treatment. The hottest (18)F-FDG standardized uptake value (SUV) in the tumor foci, the SUVs at 2 and 4 h, and the TBR2 h and TBR4 h for the target lesions were calculated (TBR2 h = SUV2 hT/SUV2 hB and TBR4 h = SUV4 hT/SUV4 hB [TBR is the tumor-to-background ratio]). Clinical outcomes of primary endocrine therapy with letrozole were evaluated according to the criteria of the World Health Organization after at least 3 mo of treatment. Immunohistochemistry for markers of proliferation (Ki67) and hypoxia-induced factor 1α was performed on a subset of tumors that had undergone biopsy or surgery. Pearson and Spearman analysis was used to determine the correlation between the parameters of (18)F-FDG and (18)F-FMISO uptake and clinical or immunohistochemistry outcomes with a 0.01 threshold for statistical significance.

RESULTS

A total of 45 lesions (13 primary, 32 metastatic) from 20 patients met the inclusion criteria in this study. Baseline (18)F-FDG and (18)F-FMISO PET/CT scans were obtained for 33 lesions from 16 patients. The correlation between baseline (18)F-FDG uptake and clinical outcome was weak and did not reach statistical significance (r = 0.37, P = 0.031). However, there was a significantly positive correlation between baseline (18)F-FMISO uptake (SUV2 hT, TBR2 h, SUV4 hT, and TBR4 h) and clinical outcomes after ≥3 mo of primary endocrine therapy with letrozole (r = 0.77, 0.76, 0.71, and 0.78, respectively; P < 0.0001). The application of a TBR4 h cutoff of ≥1.2 allowed the prediction of 88% of the cases of progressive disease (15/17). Despite poor correlation between (18)F-FMISO uptake and hypoxia-induced factor 1α expression, a marginal positive correlation between TBR4 h and Ki67 expression was measured (r = 0.51, P = 0.011) in a subset of malignant lesions acquired by biopsy or surgery.

CONCLUSION

(18)F-FMISO PET/CT can be used to predict primary endocrine resistance in ER-positive breast cancer.

Reduction of CAII Expression in Gastric Cancer: Correlation with Invasion and Metastasis

OBJECTIVE

Human carbonic anhydrases II (CAII) gene plays an important role in different cancer. However, its relevance to gastric cancer (GC) remains unclear. In the present study, we aimed to investigate the expression of CAII in GC and explore its correlation with some clinicopathologic characteristics of GC.

METHODS

The expression of CAII in 20 specimens of normal gastric mucosa, 38 specimens of intraepithelial neoplasia and 112 specimens of gastric carcinoma were detected by immunohistochemical techniques. Survival in GC with CAII expression was studied.

RESULTS

The positive rate of CAII protein in normal gastric mucosa was significantly higher than that in intraepithelial neoplasia and gastric carcinoma (100% vs. 63.16% and 28.57%, P<0.001). The positive rate of CAII protein was significantly higher in gastric carcinoma at early stages than that at advanced stages (70.0% vs. 19.57%, P<0.001). The positive rate of CAII protein was significantly lower in gastric carcinoma with lymph node metastases than that without lymph node metastases (10.81% vs. 37.33%, P<0.05). Furthermore, the positive rate of CAII protein was significantly lower in poorly-differentiated gastric carcinoma than in moderately- or well-differentiated gastric carcinoma (15.94% vs. 31.03% or 60.00%, P<0.05). Moreover, CAII expression was not related with sex, age and tumor size. The patients with CAII-positive tumors showed a better survival rate than those with CAII-negative tumors (P=0.024, log-rank test).

CONCLUSION

CAII expression was related with stages and lymph node metastases in gastric carcinoma. The reduction of CAII expression in GC might promote tumor cell motility and contribute to tumor growth and metastasis.

Synthesis and SAR of novel Re/99mTc-labeled benzenesulfonamide carbonic anhydrase IX inhibitors for molecular imaging of tumor hypoxia

Carbonic anhydrase IX (CA-IX) is upregulated in cancer in response to the hypoxic tumor microenvironment, making it an attractive molecular target for the detection of hypoxic solid tumors. A series of small molecule benzenesulfonamide based CA-IX inhibitors containing novel tridentate chelates complexed with the M(CO)(3) core (M = Re or (99m)Tc) were designed and synthesized. The in vitro binding affinity of the benzenesulfonamide rhenium complexes yielded IC(50) values ranging from 3 to 116 nM in hypoxic CA-IX expressing HeLa cells. One of the most potent compounds, 3d (IC(50) = 9 nM), was radiolabeled with technetium tricarbonyl ({(99m)Tc(CO)(3)}(+)) to afford the {(99m)Tc(CO)(3)}(+) complex in excellent yield and high purity. (99m)Tc(CO)(3)-3d bound specifically to CA-IX expressing hypoxic HeLa cells. This effort led to the identification of a diverse series of promising high affinity {(99m)Tc(CO)(3)}(+) radiolabeled CA-IX inhibitors with the potential to significantly impact diagnosis, staging, and treatment selection of hypoxic solid tumors.

Dynamics of tumor hypoxia in response to patupilone and ionizing radiation

Tumor hypoxia is one of the most important parameters that determines treatment sensitivity and is mainly due to insufficient tumor angiogenesis. However, the local oxygen concentration in a tumor can also be shifted in response to different treatment modalities such as cytotoxic agents or ionizing radiation. Thus, combined treatment modalities including microtubule stabilizing agents could create an additional challenge for an effective treatment response due to treatment-induced shifts in tumor oxygenation. Tumor hypoxia was probed over a prolonged observation period in response to treatment with different cytotoxic agents, using a non-invasive bioluminescent ODD-Luc reporter system, in which part of the oxygen-dependent degradation (ODD) domain of HIF-1α is fused to luciferase. As demonstrated in vitro, this system not only detects hypoxia at an ambient oxygen concentration of 1% O₂, but also discriminates low oxygen concentrations in the range from 0.2 to 1% O₂. Treatment of A549 lung adenocarcinoma-derived tumor xenografts with the microtubule stabilizing agent patupilone resulted in a prolonged increase in tumor hypoxia, which could be used as marker for its antitumoral treatment response, while irradiation did not induce detectable changes in tumor hypoxia. Furthermore, despite patupilone-induced hypoxia, the potency of ionizing radiation (IR) was not reduced as part of a concomitant or adjuvant combined treatment modality.

Oxygenation in cervical cancer and normal uterine cervix assessed using blood oxygenation level-dependent (BOLD) MRI at 3T

Hypoxia is reported to be a biomarker for poor prognosis in cervical cancer. However, a practical noninvasive method is needed for the routine clinical evaluation of tumor hypoxia. This study examined the potential use of blood oxygenation level-dependent (BOLD) contrast MRI as a noninvasive technique to assess tumor vascular oxygenation at 3T. Following Institutional Review Board-approved informed consent and in compliance with the Health Insurance Portability and Accountability Act, successful results were achieved in nine patients with locally advanced cervical cancer [International Federation of Gynecology and Obstetrics (FIGO) stage IIA to IVA] and three normal volunteers. In the first four patients, dynamic T₂*-weighted MRI was performed in the transaxial plane using a multi-shot echo planar imaging sequence whilst patients breathed room air followed by oxygen (15 dm³/min). Later, a multi-echo gradient echo examination was added to provide quantitative R₂* measurements. The baseline T₂*-weighted signal intensity was quite stable, but increased to various extents in tumors on initiation of oxygen breathing. The signal in normal uterus increased significantly, whereas that in the iliacus muscle did not change. R₂* responded significantly in healthy uterus, cervix and eight cervical tumors. This preliminary study demonstrates that BOLD MRI of cervical cancer at 3T is feasible. However, more patients must be evaluated and followed clinically before any prognostic value can be determined.

Operable non-small cell lung cancer: correlation of volumetric helical dynamic contrast-enhanced CT parameters with immunohistochemical markers of tumor hypoxia

PURPOSE

To assess the relationship between helical dynamic contrast material-enhanced (DCE) computed tomographic (CT) parameters and immunohistochemical markers of hypoxia in patients with operable non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

After institutional review board approval was obtained, 20 prospective patients who were suspected of having NSCLC underwent whole-tumor DCE CT with kinetic modeling (Patlak analysis) 24 hours before scheduled surgery. Flow-extraction product (in milliliters per 100 milliliters per minute) and blood volume (in milliliters per 100 milliliters) were derived. After surgery, matched whole-tumor sections were stained for exogenous and endogenous markers of hypoxia (pimonidazole infused intravenously 24 hours before surgery, immediately after DCE CT; glucose transporter protein). Correlation between DCE CT parameters and immunohistochemical markers was assessed by using the Spearman rank correlation. DCE CT parameters and immunohistochemical markers were also compared according to pathologic subtype, grade, stage, and nodal status by using the Mann-Whitney test. P values less than .05 indicated a statistically significant difference.

RESULT

Fourteen patients with confirmed primary NSCLC underwent resection. There were negative correlations between blood volume and pimonidazole staining (r = -0.48, P = .004), and between flow-extraction product and glucose transporter protein expression (r = -0.50, P = .002). Flow-extraction product was significantly higher in adenocarcinomas than in squamous cell tumors (17.73 vs 11.46; P = .043). Glucose transporter protein expression was significantly lower for adenocarcinomas than for squamous tumors (14.07 vs 33.03; P < .001) and in node negative than in node positive tumors (15.63 vs 23.85; P = .005).

CONCLUSION

Blood volume and flow-extraction product derived at DCE CT correlated negatively with pimonidazole and glucose transporter protein expression, indicating the potential of these CT parameters as imaging biomarkers of hypoxia.

SOX2 gene regulates the transcriptional network of oncogenes and affects tumorigenesis of human lung cancer cells

Recent studies demonstrated that cancer stem cells (CSCs) have higher tumorigenesis properties than those of differentiated cancer cells and that transcriptional factor-SOX2 plays a vital role in maintaining the unique properties of CSCs; however, the function and underlying mechanism of SOX2 in carcinogenesis of lung cancer are still elusive. This study applied immunohistochemistry to analyze the expression of SOX2 in human lung tissues of normal individuals as well as patients with adenocarcinoma, squamous cell carcinoma, and large cell and small cell carcinoma and demonstrated specific overexpression of SOX2 in all types of lung cancer tissues. This finding supports the notion that SOX2 contributes to the tumorigenesis of lung cancer cells and can be used as a diagnostic probe. In addition, obviously higher expression of oncogenes c-MYC, WNT1, WNT2, and NOTCH1 was detected in side population (SP) cells than in non-side population (NSP) cells of human lung adenocarcinoma cell line-A549, revealing a possible mechanism for the tenacious tumorigenic potential of CSCs. To further elucidate the function of SOX2 in tumorigenesis of cancer cells, A549 cells were established with expression of luciferase and doxycycline-inducible shRNA targeting SOX2. We found silencing of SOX2 gene reduces the tumorigenic property of A549 cells with attenuated expression of c-MYC, WNT1, WNT2, and NOTCH1 in xenografted NOD/SCID mice. By using the RNA-Seq method, an additional 246 target cancer genes of SOX2 were revealed. These results present evidence that SOX2 may regulate the expression of oncogenes in CSCs to promote the development of human lung cancer.