The tumour microenvironment: a novel target for cancer therapy

Cancer therapy is in the midst of a major paradigm shift. Traditionally, cancer treatments have focused on tumour cells. However, studies over the past few decades have demonstrated that cancer is a vastly complex entity with multiple components affecting a tumour's growth, invasion and metastasis. These components, collectively termed the 'tumour microenvironment', include endothelial cells, pericytes, fibroblasts, inflammatory cells, leucocytes and elements of the extracellular matrix (ECM). Biological agents that target components of the tumour microenvironment may provide an interesting alternative to traditional tumour cell-directed therapy. Because of the complexity of the tumour milieu, the most beneficial therapy will likely involve the combination of one or more agents directed at this new target. This review highlights recent preclinical and clinical studies involving agents that target tumour vasculature, leucocytes, pericytes, cancer-associated fibroblasts and ECM components. We pay particular attention to combination therapies targeting multiple components of the tumour microenvironment, and aim to demonstrate that this strategy holds promise for the future of cancer treatment.

A phase II trial of ZD 1869 for advanced cutaneous squamous cell carcinoma of the head and neck

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Background: Advanced HN CSSC carries a 30–40% risk of death by 2 years with standard therapies. A number of patients (pts) with clinically aggressive CSCC tend to have a poor prognosis when treated with standard approaches using surgery and radiation (RT), thus novel therapies are needed. CSSC over expresses the epidermal growth factor receptor (EGFR) and these compounds have activity in head and neck cancers. We are studying the use of gefitinib as an induction therapy in a high-risk patient group prior to definitive therapy to determine the overall efficacy, toxicity and feasibility. Methods: Eligible pts must have HN CSSC >2cm, regional nodal metastases, peri-neural invasion, or deep invasion into cartilage, muscle or bone and must be candidates for definitive local-regional therapy with surgery and/or radiation. Two 30-day cycles of gefitinib 250mg administered orally are given daily prior to definitive therapy. Pts are assessed clinically after the first 30-day cycle. If a response is noted, gefitinib is continued. For patients with stable disease, the dose is escalated to 500mg daily. Pts with progressive disease go off study. Biomarker evaluations including EGFR and Akt expression prior to and after induction are planned. Results: To date, 14 pts have been enrolled. 10 are evaluable for response and 13 for toxicity. A complete clinical response (CR) was noted in 3 pts (30%, one pathological CR), partial response in 2 patients (20%), stable disease in 2 (20%) and progressive disease in 3 (30%). Therapy was well tolerated with 2 patients having grade 3 toxicity (rash, diarrhea, or elevated liver enzymes). Conclusions: Standard definitive surgery and RT are inadequate for patients with advanced HN CSSC. The emergence of targeted therapies has given new hope for many patients with high-risk cancers. The preliminary results from our study suggest that gefitinib is an active agent for HN CSCC, and is well tolerated. Correlative studies may help identify patients most likely to respond to anti- EGFR therapy.

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S0216: A Southwest Oncology Group (SWOG) phase II trial of docetaxel (T), cisplatin (P), and fluorouracil (F) induction followed by accelerated fractionation/concomitant boost (AF/CB) radiotherapy (RT) and concurrent cisplatin for advanced head and neck squamous cell cancer (HNSCC)

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Background: Randomized trials have suggested benefit from three-drug taxane-containing induction chemotherapy, and from AF/CB RT in patients (pts) with locoregionally advanced HNSCC. In an effort to optimize non-operative therapy, this SWOG phase II trial combined these two interventions with standard concurrent single-agent cisplatin. Methods: Eligibility required a diagnosis of untreated stage III or IV (M0) HNSCC deemed appropriate for RT with curative intent, a performance status of 0–1, and adequate hematologic, renal, and hepatic function. Two courses of induction TPF (T 75 mg/m2 day (d)1, P 100 mg/m2 d1, and F 1,000 mg/m2/d as a 24 hour continuous IV infusion d1–4) were given, 21 days apart. Stable or responding pts received definitive AF/CB RT; 54 Gy in 30 fractions (fx) to the total volume, with a concomitant boost of 18 Gy in 12 fx given on the last 12 treatment days. Concurrent cisplatin (100 mg/m2) was given on d1 and d22 of the RT. An accrual of 60 pts was planned using a one-stage study design. The primary endpoint was overall survival (OS). Secondary endpoints were toxicity and response. Results: Between 3/1/03 and 8/15/04, 76 pts were enrolled; 74 were eligible and evaluable. The median age was 54 years; 82% were male, and 77% white. 52 pts (70%) had stage IV disease. 40 pts (54%) experienced at least one grade (G)4 toxicity during induction, including neutropenia in 32, with fever in 13. 62 pts completed induction and began concurrent chemoradiotherapy (CCRT); 50 completed all planned treatment. 57 pts have been evaluated for toxicity from CCRT. At least one G4 toxicity was noted in 20 pts, including neutropenia in 6, with fever in 3. There were 2 treatment-related deaths during induction, and 2 during CCRT. With a median follow-up of 27 months, the 2-year projected OS is 72% (95% CI 62%-83%), with a projected progression-free survival (PFS) of 66% (95% CI 55%-77%). Conclusions: TPF induction followed by AF/CB RT and concurrent cisplatin is toxic but feasible within a cooperative group. In this cohort of pts with advanced HNSCC, OS and PFS are encouraging, and justify further study of this approach.

No significant financial relationships to disclose.

Snowfall-Driven Growth in East Antarctic Ice Sheet Mitigates Recent Sea-Level Rise

Satellite radar altimetry measurements indicate that the East Antarctic ice-sheet interior north of 81.6 degrees S increased in mass by 45 +/- 7 billion metric tons per year from 1992 to 2003. Comparisons with contemporaneous meteorological model snowfall estimates suggest that the gain in mass was associated with increased precipitation. A gain of this magnitude is enough to slow sea-level rise by 0.12 +/- 0.02 millimeters per year.

Preferential expression of hPGFS in primary SCCHN and tumour cell lines derived from respiratory and digestive organs

Identifying overexpressed genes in tumours is a critical step for tumour diagnosis, prognosis, and treatment. Using differential display polymerase chain reaction, sequence analysis, and gene Blast searches, we discovered that human prostaglandin F synthase (hPGFS) was upregulated in squamous cell carcinoma of the head and neck (SCCHN). Northern blot analysis indicated that up to a 16-fold increase in the level of hPGFS expression was detected in 40.5% (15 out of 37) of SCCHN primary tumours. The increased expression of hPGFS in SCCHN was primarily detected in SCC of larynx and hypopharynx (59%, P<0.05). Using the same primary tissue samples, increased levels of epidermal growth factor receptor (EGFR) expression were detected in only 32% of tumour tissues, suggesting hPGFS may have the potential to become a drug target or molecular marker for SCCHN. To determine if the increased level of hPGFS expression came from tumour cells, we determined the level of hPGFS expression in SCCHN tumour cell lines. A high level of hPGFS expression was detected in four out of five tumour SCCHN cell lines. To determine if upregulation of hPGFS is SCCHN-specific, hPGFS expression was analysed in 59 tumour cell lines derived from different types of tumours. The expression of hPGFS was increased from two- to 500-fold in a large portion of cell lines derived from lung (five out of nine), colon (five out of seven) as well as head and neck cancer (four out of five). These data link hPGFS expression to tumours located in the respiratory and digestive organs.

Temperature effects on the allosteric transition of ATP sulfurylase from Penicillium chrysogenum

The effects of temperature on the initial velocity kinetics of allosteric ATP sulfurylase from Penicillium chrysogenum were measured. The experiments were prompted by the structural similarity between the C-terminal regulatory domain of fungal ATP sulfurylase and fungal APS kinase, a homodimer that undergoes a temperature-dependent, reversible dissociation of subunits over a narrow temperature range. Wild-type ATP sulfurylase yielded hyperbolic velocity curves between 18 and 30 degrees C. Increasing the assay temperature above 30 degrees C at a constant pH of 8.0 increased the cooperativity of the velocity curves. Hill coefficients (n(H)) up to 1.8 were observed at 42 degrees C. The bireactant kinetics at 42 degrees C were the same as those observed at 30 degrees C in the presence of PAPS, the allosteric inhibitor. In contrast, yeast ATP sulfurylase yielded hyperbolic plots at 42 degrees C. The P. chrysogenum mutant enzyme, C509S, which is intrinsically cooperative (n(H) = 1.8) at 30 degrees C, became more cooperative as the temperature was increased yielding n(H) values up to 2.9 at 42 degrees C. As the temperature was decreased, the cooperativity of C509S decreased; n(H) was 1.0 at 18 degrees C. The cumulative results indicate that increasing the temperature increases the allosteric constant, L, i.e., promotes a shift in the base-level distribution of enzyme molecules from the high MgATP affinity R state toward the low MgATP affinity T state. As a result, the enzyme displays a true "temperature optimum" at subsaturating MgATP. The reversible temperature-dependent transitions of fungal ATP sulfurylase and APS kinase may play a role in energy conservation at high temperatures where the organism can survive but not grow optimally.

Quality-of-life issues in head and neck cancer

Assessment of quality of life in patients with head and neck cancer presents many challenges to the clinician, especially because of the profound physical impact of disease on everyday functioning, including eating, breathing, and speech. Various assessment measures are reviewed here, and recommendations for their use under particular circumstances are outlined. General, disease-specific, site-specific, modular (both disease- and site-specific), and treatment-specific instruments are described. Other issues addressed in this review include frequency and duration of assessment, patient versus interviewer administration, and the effect of coping strategies on results.

Clinical experience with HLA-B7 plasmid DNA/lipid complex in advanced squamous cell carcinoma of the head and neck

OBJECTIVE

To investigate the safety and efficacy of alloantigen plasmid DNA therapy in patients with advanced head and neck squamous cell carcinoma using Allovectin-7 (Vical Inc, San Diego, Calif), a DNA/lipid complex designed to express the class I major histocompatibility complex antigen HLA-B7.

DESIGN

Multi-institutional prospective trial.

SETTING

Academic medical setting.

PATIENTS

A total of 69 patients were enrolled in 3 sequential clinical trials: a single-center phase 1 trial and 2 multicenter phase 2 trials. Eligibility criteria included unresectable squamous cell carcinoma that failed conventional therapy, Karnofsky performance status score of 70 or greater, and no concurrent anticancer or immunosuppressive therapies.

INTERVENTION

Patients received 2 biweekly intratumoral injections of 10 microg (phase 1 and first phase 2 trials) or 100 microg (second phase 2 trial) of Allovectin-7 followed by 4 weeks of observation. Patients with stable or responding disease after the observation period were given a second treatment cycle identical to the first.

MAIN OUTCOME MEASURES

Patients were assessed for toxic effects, and tumor size was measured after cycles 1 (at 6 weeks) and 2 (at 16 weeks).

RESULTS

Allovectin-7 treatment was well tolerated, with no grade 3 or 4 drug-related toxic effects. Of 69 patients treated, 23 (33%) had stable disease or a partial response after the first cycle of treatment and proceeded to the second cycle. After the second cycle, 6 patients had stable disease, 4 had a partial response, and 1 had a complete response. Responses persisted for 21 to 106 weeks.

CONCLUSIONS

Intratumoral plasmid DNA immunotherapy for head and neck cancer with Allovectin-7 is safe, and further investigations are planned in patients with less advanced disease, where it could potentially improve patient survival and reduce the need for radical high-morbidity treatments.

Is glutathione-S-transferase-pi expression a reliable predictor of chemoradiation response in cancer of the head and neck?

PURPOSE

Concurrent radiation and chemotherapy is being evaluated as an alternative treatment to surgery for patients with advanced squamous cell carcinoma of the head and neck, because organ preservation maybe possible without compromising survival. However, the response to concurrent chemoradiation treatment varies from patient to patient, and there is currently no available molecular predictor of response for this particular treatment modality. There is some evidence to indicate that glutathione S-transferase-pi (GST-pi), which is one of the drug detoxifying enzymes, may decrease the effectiveness of platinum-based chemotherapy in the treatment of a variety of tumor types. This study was performed to investigate whether GST-pi expression was correlated with response to concurrent chemotherapy and radiotherapy in patients with advanced squamous cell carcinoma of the head and neck.

MATERIALS AND METHODS

Diagnostic biopsy specimens of 36 patients who underwent concurrent chemoradiotherapy for the treatment of advanced squamous cell carcinoma of the head and neck were examined for GST-pi expression by using immunohistochemistry with polyclonal antihuman GST-pi antibodies. GST-pi expression scores were compared among responders and nonresponders.

RESULTS

Although the staining rate with antiGST-pi was slightly lower in the responder group in comparison with the nonresponders (82% vs 100%), the difference was not statistically significant.

CONCLUSION

GST-pi expression is unlikely to be a valuable predictor of response to concurrent chemotherapy and radiation treatment in patients with advanced squamous cell carcinoma of the head and neck.

Thriving in a changing environment

Undeniably, working in an environment that challenges the status quo is not without its problems. Members of the service redesign teams who participated in the West Ottawa Valley Network experience confess that many times during the process they felt a threat to their own job security along with uncertainty about their future roles and responsibilities. June Merkley points out that "working outside one's "normal comfort level" in a non-traditional leadership role has it's own set of difficulties, and dealing with multiple network members adds a dimension of complexity not encountered at the single site level." But she believes that "the challenges encountered within the network are helping to broaden the scope of job knowledge and communication skills. This can only have a direct and positive impact on the day-to-day tasks, while providing value to both the employee and employer". As a career management strategy, healthcare managers should seek out opportunities beyond their normal range of accountability, participate in activities that encourage the growth of new skills or hone skills that are a bit rusty. Often these projects will cause some anxiety or discomfort but the rewards, both short and long term, far outweigh the short-term pain.

A novel alternative approach for prediction of radiation response of squamous cell carcinoma of head and neck

Accurate prediction of human tumor response to radiation therapy and concomitant chemoradiation would be an important tool to assist the physician in making recommendations for tumor treatment. Most of the studies that define the molecular markers for prediction of radiation response are based on the observation of gene expression using immunostaining, Northern blot, or Western blot analysis of a single or several genes. The results vary among different studies, and some results are contradictory. However, the studies agree that the change in expression of the tumor-related gene affects the radiation response. In this study, we explored a novel approach to predict the radiation response of human tumor using Atlas human cancer 1.2 cDNA array to analyze the expression profile of 1187 tumor-related genes in radiation-resistant and radiation-sensitive tissues. Sixty tumor-related genes were selected as predictors of radiation response of squamous cell carcinoma of the head and neck. Using the expression intensity of these 60 tumor-related genes, in combination with cluster analysis, we successfully predicted the radiation identity of two tumor samples.

Intramuscular electroporation delivery of IL-12 gene for treatment of squamous cell carcinoma located at distant site

Gene therapy with IL-12 has been shown to elicit potent systemic antitumor response in a variety of tumors. Although direct intratumoral injection is the most commonly used delivery route for gene therapy of solid tumors, the skeletal muscle has been shown to be an ideal tissue for gene delivery to produce systemic gene expression. We have previously demonstrated that electroporation delivery of a reporter gene to muscle enhances the transfection efficiency and the level of gene expression by two to three logs. We report here that intramuscular (i.m.) injection of as little as 10 microg of the IL-12 DNA plasmid followed by electroporation prevents squamous cell carcinoma (SCCVII) tumor establishment in up to 40% of experimental animals and reduces the volume of established tumors by 75% compared to controls (P<.05). By comparison, there was no difference in tumor growth observed between IL-12 injection alone and injection of empty vector with or without electroporation. The induction of antitumor activity by i.m. electroporation delivery of the IL-12 gene is associated with an increase in IL-12 expression in muscle and serum. The level of IL-12 expression in muscle and serum was 1500 pg/tibialias muscle and 170 pg/mL serum, respectively, at day 6, after the gene was delivered by electroporation. In contrast, the level of IL-12 when the gene was injected without electroporation was hardly detectable after subtracting the background level of IL-12 detected in naïve mice. The high level of IL-12 expression led to a 170-fold induction of IFN-gamma expression in serum at day 6 after i.m. electroporation delivery of IL-12 DNA plasmid, which was equal to 1450 pg/mL in the serum. The induction of antitumor activity by i.m. electroporation delivery of the IL-12 gene also correlates with increased CD8+ T-cell population in peripheral blood but not in spleen. Our findings suggest that i.m. delivery of IL-12 gene using electroporation is an effective method of inducing a systemic antitumor response against SCC.

Intramuscular electroporation delivery of IFN-alpha gene therapy for inhibition of tumor growth located at a distant site

Although electroporation has been shown in recent years to be a powerful method for delivering genes to muscle, no gene therapy via electro-injection has been studied for the treatment of tumors. In an immunocompetent tumor-bearing murine model, we have found that delivery of a low dose of reporter gene DNA (10 microg) to muscle via electroporation under specific pulse conditions (two 25-ms pulses of 375 V/cm) increased the level of gene expression by two logs of magnitude. Moreover, administration of 10 microg of interferon (IFN)-alpha DNA plasmid using these parameters once a week for 3 weeks increased the survival time and reduced squamous cell carcinoma (SCC) growth at a distant site in the C3H/HeJ-immunocompetent mouse. IFN-alpha gene therapy delivered to muscle using electroporation demonstrated statistically significant (P < 0.05) therapeutic efficacy for treating SCC located at a distant site, compared with interleukin (IL)-2 or endostatin gene, also delivered by electro-injection. The increased therapeutic efficacy was associated with a high level and extended duration of IFN-alpha expression in muscle and serum. We also discovered that the high level of IFN-alpha expression correlated with increased expression levels of the antiangiogenic genes IP-10 and Mig in local tumor tissue, which may have led to the reduction of blood vessels observed at the local tumor site. Delivery of increasing doses (10-100 microg) of IFN-alpha plasmid DNA by injection alone did not increase antitumor activity, whereas electroporation delivery of increasing doses (10-40 microg) of IFN-alpha plasmid DNA did increase the survival time. Our data clearly demonstrate the potential utility of electroporation for delivery of gene therapy to muscle for the treatment of residual or disseminated tumors.

Genetic deletions of glutathione-S-transferase as a risk factor in squamous cell carcinoma of the larynx: a preliminary report

PURPOSE

To test whether genetic deletions of glutathione-S-transferase (GST) are associated with squamous cell carcinoma (SCC) of the larynx. GST are a group of detoxifying enzymes that may help reduce the risk of developing cancer in response to environmental carcinogens. Polycyclic aromatic hydrocarbons, found in high concentration in cigarette smoke, are known carcinogens especially for SCC of the larynx. Individuals with absolute or relative deficiency of the GST enzyme system may therefore be at a higher risk of developing laryngeal carcinoma.

MATERIALS AND METHODS

Genotyping for GST-M1 and GST-T1 was performed using polymerase chain reaction (PCR) assay on fresh frozen tissue specimens of 20 patients with SCC of the larynx and on 20 control subjects with a similar smoking history. Because this assay results in the absence of a PCR product in individuals expressing the GST-M1/GST-T1 null genotype, oligonucleotide primers that amplify a portion of the albumin gene were included in a multiplex PCR as a positive control for DNA quality and PCR conditions. The chi-square test was used for statistical analysis.

RESULTS

GST-M1 gene was deleted in 80% of patients with laryngeal SCC and in 50% of control subjects (P <.05). No statistically significant difference was observed in the incidence of GST-T1 gene deletion in patients with SCC of the larynx and control subjects.

CONCLUSION

GST-M1 gene deletion was significantly associated with SCC of the larynx and may produce a risk for this particular disease.

Coping with head and neck cancer during different phases of treatment

BACKGROUND

Little is known about how patients cope with head and neck cancer despite its devastating impact on basic functioning. This study examined coping patterns among patients at different phases of illness.

METHODS

Participants were 120 patients with advanced disease, who were grouped according to the following phases of illness: (1) pretreatment, (2) on treatment, (3) <6 months after treatment, and (4) >6 months after treatment. Coping was assessed with the COPE questionnaire, and outcome measures assessed general distress (Profile of Mood States) and illness-specific distress (Impact of Events Scale).

RESULTS

Use of specific coping responses differed among the groups. Denial (p <.05), behavioral disengagement (ie, giving up or withdrawing, p <.05), suppression of competing activities (ie, focusing exclusively on the illness, p <.01), and emotional ventilation (p <.10) were most characteristic of patients who were receiving or had recently completed treatment. There were no differences in flexibility of coping or overall effort expended, but patients who were on treatment or who had recently completed treatment used the greatest number of strategies. Generally, denial, behavioral disengagement, and emotional ventilation were associated with greater distress.

CONCLUSIONS

Results suggest that phase of illness may be important in shaping patients' responses to life-threatening illness.

Induction of positive cooperativity by amino acid replacements within the C-terminal domain of Penicillium chrysogenum ATP sulfurylase

ATP sulfurylase from Penicillium chrysogenum is an allosteric enzyme in which Cys-509 is critical for maintaining the R state. Cys-509 is located in a C-terminal domain that is 42% identical to the conserved core of adenosine 5'-phosphosulfate (adenylylsulfate) (APS) kinase. This domain is believed to provide the binding site for the allosteric effector, 3'-phosphoadenosine 5'-phosphosulfate (PAPS). Replacement of Cys-509 with either Tyr or Ser destabilizes the R state, resulting in an enzyme that is intrinsically cooperative at pH 8 in the absence of PAPS. The kinetics of C509Y resemble those of the wild type enzyme in which Cys-509 has been covalently modified. The kinetics of C509S resemble those of the wild type enzyme in the presence of PAPS. It is likely that the negative charge on the Cys-509 side chain helps to stabilize the R state. Treatment of the enzyme with a low level of trypsin results in cleavage at Lys-527, a residue that lies in a region analogous to a PAPS motif-containing mobile loop of true APS kinase. Both mutant enzymes were cleaved more rapidly than the wild type enzyme, suggesting that movement of the mobile loop occurs during the R to T transition.