Prospective technical validation and assessment of intra-tumour heterogeneity of a low density array hypoxia gene profile in head and neck squamous cell carcinoma.

BACKGROUND AND PURPOSE: Tumour hypoxia is associated with a poor prognosis in head and neck squamous cell carcinoma (HNSCC), however there is no accepted method for assessing hypoxia clinically. We aimed to conduct a technical validation of a hypoxia gene expression signature using the TaqMan Low Density Array (TLDA) platform to investigate if this approach reliably identified hypoxic tumours. MATERIALS AND METHODS: Tumour samples (n=201) from 80 HNSCC patients were collected prospectively from two centres. Fifty-three patients received pimonidazole prior to surgery. TaqMan Low Density Array-Hypoxia Scores (TLDA-HS) were obtained by quantitative real-time PCR (qPCR) using a 25-gene signature and customised TLDA cards. Assay performance was assessed as coefficient of variation (CoV). RESULTS: The assay was sensitive with linear reaction efficiencies across a 4 log(10) range of inputted cDNA (0.001-10 ng/µl). Intra- (CoV=6.9%) and inter- (CoV=2.0%) assay reproducibility were excellent. Intra-tumour heterogeneity was lower for TLDA-HS (23.2%) than for pimonidazole (67.2%) or single gene measurements of CA9 (62.2%), VEGFA (45.0%) or HIG2 (39.4%). TLDA-HS in HNSCC cell lines increased with decreasing pO(2). TLDA-HS correlated with Affymetrix U133 Plus 2.0 microarray HS (p<0.01) and positive pimonidazole scores (p=0.005). CONCLUSIONS: Gene expression measurements of hypoxia using a 25-gene signature and TLDA cards are sensitive, reproducible and associated with lower intra-tumour heterogeneity than assaying individual genes or pimonidazole binding. The approach is suitable for further assessment of prognostic and predictive capability in clinical trial material.

Importance of intracellular pH in determining the uptake and efficacy of the weakly basic chemotherapeutic drug, doxorubicin.

Low extracellular pH (pH(e)), that is characteristic of many tumours, tends to reduce the uptake of weakly basic drugs, such as doxorubicin, thereby conferring a degree of physiological resistance to chemotherapy. It has been assumed, from pH-partition theory, that the effect of intracellular pH (pH(i)) is symmetrically opposite, although this has not been tested experimentally. Doxorubicin uptake into colon HCT116 cells was measured using the drug's intrinsic fluorescence under conditions that alter pH(i) and pH(e) or pH(i) alone. Acutely, doxorubicin influx across the cell-membrane correlates with the trans-membrane pH-gradient (facilitated at alkaline pH(e) and acidic pH(i)). However, the protonated molecule is not completely membrane-impermeant and, therefore, overall drug uptake is less pH(e)-sensitive than expected from pH-partitioning. Once inside cells, doxorubicin associates with slowly-releasing nuclear binding sites. The occupancy of these sites increases with pH(i), such that steady-state drug uptake can be greater with alkaline cytoplasm, in contradiction to pH-partition theory. Measurements of cell proliferation demonstrate that doxorubicin efficacy is enhanced at alkaline pH(i) and that pH-partition theory is inadequate to account for this. The limitations in the predictive power of pH-partition theory arise because it only accounts for the pH(i)/pH(e)-sensitivity of drug entry into cells but not the drug's subsequent interactions that, independently, show pH(i)-dependence. In summary, doxorubicin uptake into cells is favoured by high pH(e) and high pH(i). This modified formalism should be taken into account when designing manoeuvres aimed at increasing doxorubicin efficacy.

Carbonic anhydrase IX promotes tumor growth and necrosis in vivo and inhibition enhances anti-VEGF therapy.

PURPOSE: Bevacizumab, an anti-VEGFA antibody, inhibits the developing vasculature of tumors, but resistance is common. Antiangiogenic therapy induces hypoxia and we observed increased expression of hypoxia-regulated genes, including carbonic anhydrase IX (CAIX), in response to bevacizumab treatment in xenografts. CAIX expression correlates with poor prognosis in most tumor types and with worse outcome in bevacizumab-treated patients with metastatic colorectal cancer, malignant astrocytoma, and recurrent malignant glioma. EXPERIMENTAL DESIGN: We knocked down CAIX expression by short hairpin RNA in a colon cancer (HT29) and a glioblastoma (U87) cell line which have high hypoxic induction of CAIX and overexpressed CAIX in HCT116 cells which has low CAIX. We investigated the effect on growth rate in three-dimensional (3D) culture and in vivo, and examined the effect of CAIX knockdown in combination with bevacizumab. RESULTS: CAIX expression was associated with increased growth rate in spheroids and in vivo. Surprisingly, CAIX expression was associated with increased necrosis and apoptosis in vivo and in vitro. We found that acidity inhibits CAIX activity over the pH range found in tumors (pK = 6.84), and this may be the mechanism whereby excess acid self-limits the build-up of extracellular acid. Expression of another hypoxia inducible CA isoform, CAXII, was upregulated in 3D but not two-dimensional culture in response to CAIX knockdown. CAIX knockdown enhanced the effect of bevacizumab treatment, reducing tumor growth rate in vivo. CONCLUSION: This work provides evidence that inhibition of the hypoxic adaptation to antiangiogenic therapy enhances bevacizumab treatment and highlights the value of developing small molecules or antibodies which inhibit CAIX for combination therapy.

Oral steroids for nasal polyps.

BACKGROUND: This is an update of a Cochrane Review first published in The Cochrane Library in Issue 1, 2007.Benign nasal polyps are lesions that arise from the mucosa of the nasal cavity or one or more of the nasal sinuses. The presenting symptoms are nasal obstruction, watery anterior rhinorrhoea (excessive nasal secretions) or mucopurulent postnasal drip (or both), hyposmia and anosmia (reduced or absent sense of smell) with a concomitant alteration in taste and infrequently pain over the dorsum of the nose, forehead and cheeks. The main aim of treatment is to relieve these symptoms. The aetiology of polyps is uncertain, therefore treatment options differ, consisting of a combination of medical and surgical management. Medical therapy is mainly in the form of steroids, administered topically or systemically via the oral route. OBJECTIVES: To assess the effects of oral steroids in patients with multiple nasal polyps. SEARCH STRATEGY: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ISRCTN and additional sources for published and unpublished trials. The date of the most recent search was 12 October 2010, following a previous search in April 2006. SELECTION CRITERIA: Randomised controlled trials and controlled clinical trials comparing oral steroids with no intervention, or placebo, or comparing doses or schedules of oral steroids in patients with multiple nasal polyps. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study quality. We contacted study authors for additional information. MAIN RESULTS: Three trials (166 patients) met our inclusion criteria and showed a short-term benefit of a short (two to four-week) course of oral steroids of variable doses and duration when compared to placebo. There was an objective reduction of polyp size and a subjective improvement of nasal symptoms and quality of life. However, due to the moderate to low quality of these trials it was not possible to quantify the overall size of this effect.There was no report of significant adverse effects of treatment with a short course of steroids. AUTHORS' CONCLUSIONS: The authors found three randomised controlled trials, albeit of moderate to poor quality, that suggest a short-term benefit of oral steroids in patients with multiple nasal polyps. To address the issue more thoroughly well-designed, prospective, randomised controlled trials are still needed.

Spectral clustering of microarray data elucidates the roles of microenvironment remodeling and immune responses in survival of head and neck squamous cell carcinoma.

PURPOSE: To identify functionally related prognostic gene sets for head and neck squamous cell carcinoma (HNSCC) by unsupervised statistical analysis of microarray data. PATIENTS AND METHODS: Microarray analysis was performed on 14 normal oral epithelium and 71 HNSCCs from patients with outcome data. Spectral clustering (SC) analysis of the data set identified multiple vectors representing distinct aspects of gene expression heterogeneity between samples. Gene ontology (GO) analysis of vector gene lists identified gene sets significantly enriched within defined biologic pathways. The prognostic significance of these was established by Cox survival analysis. RESULTS: The most influential SC vectors were V2 and V3. V2 separated normal from tumor samples. GO analysis of V2 gene lists identified pathways with heterogeneous expression between HNSCCs, notably focal adhesion (FA)/extracellular matrix remodeling and cytokine-cytokine receptor (CR) interactions. Similar analysis of V3 gene lists identified further heterogeneity in CR pathways. V2CR genes represent an innate immune response, whereas high expression of V3CR genes represented an adaptive immune response that was not dependent on human papillomavirus status. Survival analysis demonstrated that the FA gene set was prognostic of poor outcome, whereas classification for adaptive immune response by the CR gene set was prognostic of good outcome. A combined FA&CR model dramatically exceeded the performance of current clinical classifiers (P < .001 in our cohort and, importantly, P = .007 in an independent cohort of 60 HNSCCs). CONCLUSION: The application of SC and GO algorithms to HNSCC microarray data identified gene sets highly significant for predicting patient outcome. Further large-scale studies will establish the usefulness of these gene sets in the clinical management of HNSCC.

hsa-mir-210 is a marker of tumor hypoxia and a prognostic factor in head and neck cancer.

BACKGROUND: Hypoxia is an important mechanism of treatment resistance in head and neck squamous cell carcinoma (HNSCC). MicroRNAs are short noncoding RNAs that regulate multiple mRNAs and are frequently dysregulated in cancer. The authors have investigated the role of 3 microRNAs, including the hypoxia-induced hsa-miR-210, as potential markers of hypoxia or prognosis. METHODS: Three hypoxia-related microRNAs, hsa-miR-210, hsa-miR-21, and hsa-miR-10b, were measured in 46 samples from patients with HNSCC. Expression levels were correlated with clinicopathological variables and other markers of hypoxia: a published 99-gene hypoxia metagene, individual hypoxia-related genes such as TWIST1, and immunohistochemical expression of hypoxia-inducible factor 1 and its target gene carbonic anhydrase 9. We then performed survival analyses to investigate the prognostic significance of these microRNAs. RESULTS: Only the level of hsa-miR-210 was significantly correlated with other markers of hypoxia, including the 99-gene hypoxia metagene (rho = 0.67, P < .001). We found no association between hsa-miR-210, hsa-miR-21, or hsa-miR-10b and clinicopathological variables such as tumor size, differentiation, and stage. However, high levels of hsa-miR-210 were associated with locoregional disease recurrence (P = .001) and short overall survival (P = .008). hsa-miR-21 and hsa-miR-10b had no prognostic significance. CONCLUSIONS: Expression of hsa-miR-210 in head and neck cancer correlates with other approaches for assessing hypoxia and is associated with prognosis. This warrants further study as a classification marker of patients for therapies involving modulation of hypoxia.

The role of carbonic anhydrase 9 in regulating extracellular and intracellular ph in three-dimensional tumor cell growths.

We have studied the role of carbonic anhydrase 9 (CA9), a cancer-associated extracellular isoform of the enzyme carbonic anhydrase in multicellular spheroid growths (radius of approximately 300 microm) of human colon carcinoma HCT116 cells. Spheroids were transfected with CA9 (or empty vector) and imaged confocally (using fluorescent dyes) for both intracellular pH (pH(i)) and pH in the restricted extracellular spaces (pH(e)). With no CA9 expression, spheroids developed very low pH(i) (approximately 6.3) and reduced pH(e) (approximately 6.9) at their core, associated with a diminishing gradient of acidity extending out to the periphery. With CA9 expression, core intracellular acidity was less prominent (pH(i) = approximately 6.6), whereas extracellular acidity was enhanced (pH(e) = approximately 6.6), so that radial pH(i) gradients were smaller and radial pH(e) gradients were larger. These effects were reversed by eliminating CA9 activity with membrane-impermeant CA inhibitors. The observation that CA9 activity reversibly reduces pH(e) indicates the enzyme is facilitating CO(2) excretion from cells (by converting vented CO(2) to extracellular H(+)), rather than facilitating membrane H(+) transport (such as H(+) associated with metabolically generated lactic acid). This latter process requires titration of exported H(+) ions with extracellular HCO(3)(-), which would reduce rather than increase extracellular acidity. In a multicellular structure, the net effect of CA9 on pH(e) will depend on the cellular CO(2)/lactic acid emission ratio (set by local oxygenation and membrane HCO(3)(-) uptake). Our results suggest that CO(2)-producing tumors may express CA9 to facilitate CO(2) excretion, thus raising pH(i) and reducing pH(e), which promotes tumor proliferation and survival. The results suggest a possible basis for attenuating tumor development through inhibiting CA9 activity.

Patient satisfaction with NHS elective tonsillectomy outsourced to the private sector under the Patient Choice Programme.

RATIONALE, AIMS AND OBJECTIVES: An interim goal of the NHS 'Extending choice for patients' initiative was that, by 2004, patients who had been on the NHS waiting list for elective surgery for 6 months were provided with a choice of staying on the waiting list or being treated faster by opting to have their operation with an alternative provider. The aim of this study was to examine patient satisfaction in a cohort of patients who travelled out-of-region to undergo routine tonsillectomy performed by an NHS consultant at a private hospital. METHOD: A questionnaire survey was conducted of adult patients undergoing elective tonsillectomy in 2002 and 2003 at The Hampshire Clinic, Basingstoke, UK. RESULTS: Our results showed that 95% (n = 123) of patients were happy to travel considerable distances from their local hospital to have their operation. Overall 71% (n = 92) of patients rated the overall experience of having the operation performed at the private hospital as excellent and 25% (n = 32) rated it as satisfactory. CONCLUSION: We conclude that tonsillectomy performed by a consultant in an out-of-region private hospital is associated with a high level of patient satisfaction and is an acceptable way to reduce waiting times for tonsillectomy provided clear guidelines and safeguards are in place.

Partial middle turbinectomy by nasotracheal intubation.

Partial middle turbinate avulsion is a rare complication of nasotracheal intubation. Patients usually experience a brisk hemorrhage at the time of injury. Postoperatively, some patients develop a unilateral nasal obstruction, while others are asymptomatic. We present an unusual case in which a patient became symptomatic many years after the incident. We hope to raise awareness that a traumatic disruption of the turbinates secondary to nasotracheal intubation might lead to the development of an abnormal nasopharyngeal mass.

Role of hypoxia-inducible factor-1alpha as a cancer therapy target.

Hypoxia occurs in solid tumours due to a mismatch between tumour growth and angiogenesis. Hypoxia in solid tumours is associated with an aggressive phenotype and resistance to radiation therapy and chemotherapy leading to poor patient prognosis. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor, which is activated in response to intratumoural hypoxia and as a result of genetic alterations that activate oncogenes and inactivate tumour suppressor genes. It plays a key role in the adaptation of tumour cells to hypoxia by activating the transcription of genes, which regulate several biological processes including angiogenesis, cell proliferation and survival, glucose metabolism, pH regulation and migration. This makes HIF-1 an attractive target for the development of anticancer agents. The success of these agents depends on reliable methods to identify those patients most likely to benefit from HIF-1-targeted therapy. Several novel small molecule inhibitors of HIF-1 have been identified and are moving towards clinical trials, but none of these are specific for HIF-1. Further work is ongoing to identify more selective HIF-1 inhibitors.

Smoking causes a dose-dependent increase in granulocyte-bound L-selectin.

The mechanism by which cigarette smoking promotes atherosclerosis remains unclear but may involve the endothelium and leukocytes. We postulated a direct acute effect of cigarette smoking on the endothelium and granulocytes by measuring granulocyte expression of L-selectin (flow cytometry) and serum L- and E-selectin (ELISA) before and after smoking in 12 smokers with peripheral vascular disease (claudicants) and 12 otherwise healthy controls. Mean (S.D.) granulocyte L-selectin, expressed as mean fluorescence intensity (MFI), increased in a dose-dependent fashion from 3.58+/-0.67 and 3.27+/-0.67 in controls and claudicants, respectively, to 3.77+/-0.75 and 3.49+/-0.79 10 min after smoking two cigarettes (p<0.002), and to 4.11+/-0.95 and 3.67+/-0.88 30 min after four cigarettes (p<0.001). Serum L-selectin was lower in claudicants at all time points throughout the study period compared with controls (p<0.005) but neither serum E- nor L-selectin levels changed following smoking. Smoking led to an increase in granulocyte expression of L-selectin, which may be important in granulocyte/endothelial adhesion and thus related to atherosclerosis. The lower serum L-selectin levels in claudicants, and the absence of a rise in serum adhesion molecules on smoking, suggests consumption by activated endothelial receptors that may be part of a negative feedback mechanism.