Immunogenicity after two and three doses of mRNA vaccine in patients with cancer treated with exclusive radiotherapy.

BACKGROUND AND PURPOSE: Data on immunoresponse after SARS-CoV-2 vaccines for patients treated with exclusive radiotherapy (RT) are scarce. Since RT may affect the immune system, we conducted the MORA trial (Antibody response and cell-mediated immunity of MOderna mRNA-1273 vaccine in patients treated with RAdiotherapy). MATERIALS AND METHODS: Data regarding humoral and cellular immune response of patients treated with RT were prospectively collected after the second and third dose of mRNA vaccines. RESULTS: Ninety-two patients were enrolled. With a median of 147 days after the second dose, the median SARS-CoV-2 IgG titer was 300 BAU/mL: six patients were seronegative (Spike IgG titer ≤ 40 BAU/mL), whereas 24, 46 and 16 were poor responders (Spike IgG titer:41-200 BAU/mL), responders (Spike IgG titer:201-800 BAU/mL) and ultraresponders (Spike IgG titer > 800 BAU/mL), respectively. Among seronegative patients, two patients were negative also for cell mediated response, as tested with IFN-γ release Assay (IGRA) test. With a median of 85 days after the third dose, the median SARS-CoV-2 IgG titer was 1632 BAU/mL in 81 patients: only two patients were seronegative, whereas 16 and 63 patients were responders and ultraresponders, respectively. Among the 2 persistently seronegative patients, IGRA test was negative in one who had previously received anti-CD20 therapy. Documented paucisymptomatic (n = 3) or asymptomatic (n = 4) infection occurred after the third dose, during the Omicron wave. CONCLUSION: In patients treated with exclusive RT, even during the Omicron breakthrough, robust humoral response and clinical protection from severe SARS-CoV-2 disease were achievable with three doses of mRNA vaccine.

The Relationship Between Covid-19 Risk Perception and Vaccine Hesitancy in Cancer Patients: The Moderating Role of Externalizing Traits.

Objective: This mixed-methods study aimed to explore the role of externalizing traits in moderating the relationship between COVID-19 risk perception and vaccine hesitancy in patients diagnosed with cancer. A community-based participatory approach - comprising a preliminary qualitative inquiry and a subsequent cross-sectional research - was used to promote effective vaccination campaigns. Method: 12 people diagnosed with cancer and 7 cancer professionals were recruited for the qualitative inquiry, 356 people either under cancer treatment or in follow-up care for the cross-sectional research.A phenomenological analysis explored the transcripts of two focus groups. The cross-sectional research tested the hypothesis emerged during the previous qualitative inquiry through self-reported questionnaires and moderated regression. Results: Phenomenological analysis suggested a pivotal role of externalizing traits in vaccine hesitancy. Moderated regression revealed how the association between risk perception and vaccine hesitancy is moderated by externalizing traits, even when controlled for treatment adherence. Conclusions: In the present study we found a stronger relationship between risk perception and vaccine hesitancy for patients with higher levels of externalizing traits. We suggest that vaccination campaigns should be personality-informed to offer individualized and effective solutions. Patients with externalizing traits may cope dysfunctionally with vaccination campaigns.

Be-TeaM: An Italian real-world observational study on second-line therapy for EGFR-mutated NSCLC patients.

OBJECTIVES: Molecular diagnostics and care of non-small cell lung cancer (NSCLC) are continuously evolving. Few data document the current strategies to manage advanced NSCLC patients beyond progression in clinical practice. PATIENTS AND METHODS: Be-TeaM is an Italian multi-center observational study conducted on consecutive EGFR-mutated stage IV NSCLC patients, progressed during/after a first-line EGFR-TKI. It consists of a retrospective phase, from first-line EGFR-TKI therapy start until study entry (i.e. beginning of the diagnostic process), and a prospective phase, until treatment choice or for 3 months if no therapy was prescribed. Primary objective was to describe the diagnostic and therapeutic approaches adopted after progression in a real-world setting. RESULTS: Of 308 patients enrolled in 63 centers from July 2017 to June 2018, 289 were included in the analysis. In first line, 53.3 % received gefitinib, 32.5 % afatinib and 14.2 % erlotinib. The testing rate (i.e. rate of all patients undergone any biopsy -liquid and/or tissue- for the T790 M detection) was 90.7 %, with liquid biopsy being the most frequently executed. Of 262 biopsied patients, 64.5 % underwent only 1 liquid biopsy, 10.7 % only 1 tissue biopsy and 18.3 % >1 biopsy, both liquid and solid in 85.4 %. The T790M positivity rate was 45.3 %; of 166 patients undergone only a liquid biopsy and tested for the mutation, 39.8 % were T790M+ and 60.2 % T790M-/undetermined. By the observation end, 87.9 % patients had a post-progression treatment chosen, osimertinib being the most frequent among the T790M+. CONCLUSION: Be-TeaM provides the first snapshot of current practices for the management of NSCLC patients beyond progression in Italy; in clinical practice, assessing the T790M status is not always feasible.

Class 1, 2, and 3 BRAF-Mutated Metastatic Colorectal Cancer: A Detailed Clinical, Pathologic, and Molecular Characterization.

PURPOSE: BRAF mutations are grouped in activating RAS-independent signaling as monomers (class 1-V600E) or as dimers (class 2-codons 597/601), and RAS-dependent with impaired kinase activity (class 3-codons 594/596). Although clinical, pathologic, and molecular features of V600EBRAF-mutated metastatic colorectal cancer (mCRC) are well known, limited data are available from the two other classes. EXPERIMENTAL DESIGN: Data from 117 patients with BRAF (92 class 1, 12 class 2, and 13 class 3)-mutated mCRC were collected. A total of 540 BRAF wt mCRCs were included as control. IHC profiling was performed to determine the consensus molecular subtypes (CMS), cytokeratin 7/20 profiles, tumor-infiltrating lymphocyte infiltration, and BM1/BM2 categorization. Overall survival (OS) and progression-free survival were evaluated by Kaplan-Meier and log-rank test. RESULTS: Class 3 BRAF-mutated mCRC was more frequently left sided (P = 0.0028), pN0 (P = 0.0159), and without peritoneal metastases (P = 0.0176) compared with class 1, whereas class 2 cases were similar to class 1. Hazard ratio for OS, as compared with BRAF wt, was 2.38 [95% confidence interval (CI), 1.61-3.54] for class 1, 1.90 (95% CI, 0.85-4.26) for class 2, and 0.93 (95% CI, 0.51-1.69) for class 3 (P < 0.0001). Class 2 and 3 tumors were all assigned to CMS2-3. A higher median CD3/CD8-positive lymphocyte infiltration was observed in BRAF-mutated class 2 (P = 0.033) compared with class 3 cases. CONCLUSIONS: For the first time, different clinical and pathologic features and outcome data were reported according to the three BRAF mutation classes in mCRC. Specific targeted treatment strategies should be identified in the near future for such patients.

Prevalence, characteristics, and treatment of fatigue in oncological cancer patients in Italy: a cross-sectional study of the Italian Network for Supportive Care in Cancer (NICSO).

BACKGROUND: Fatigue is one of the most distressing symptoms of cancer patients. Its characteristics and impact on quality of life have not been fully explored and treatment of cancer-related fatigue in Italian oncological centers has not been codified. METHODS: A cross-sectional study was carried out on all patients attending for any reason the 24 participating centers in two non-consecutive days. Patients with fatigue filled out the Brief Fatigue Inventory (BFI) questionnaire and reported any pharmacological or non-pharmacological treatment for fatigue. RESULTS: From October 2014 to May 2015, 1394 cancer patients agreed to participate in the study. Fatigue was referred by 866 (62.1%) of patients; its duration was > 4 months in 441 patients (50.9%). In the investigators' opinion, the most important (probable or almost sure) determinants of fatigue were reduced physical activity (271 patients), anxiety (149), pain (131), insomnia (125), anemia (123), and depression (123). Fatigue of moderate/severe intensity was reported by 43%/29.2% of patients, while usual fatigue in the last 24 h by 45%/33.1%, and the worst fatigue in the last 24 h by 33%/54.8%, respectively. Concerning the impact on quality of life, fatigue interfered moderately/severely with general activity in 30.8%/38.6% of patients, with mood in 26.1%/32.8%, with the ability to work in 27.9%/35.6%, with normal work in 26.7%/38.9%, with relationships with others in 21%/23.4% and with the ability to amuse themselves in 22.2%/33.1%. Only 117/866 patients (13.5%) received a pharmacological treatment represented by a corticosteroid in 101 patients (86.3%) while 188 patients (21.7%) received a non-pharmacological treatment such as physical exercise (120 patients, 63.8%) and various alimentary supplements (52 patients, 27.6%). CONCLUSIONS: Cancer-related fatigue is frequently reported by oncological patients; its intensity and impact on quality of life is relevant.

Systematic vs. on-demand early palliative care in gastric cancer patients: a randomized clinical trial assessing patient and healthcare service outcomes.

PURPOSE: Early palliative care (EPC) has shown a positive impact on quality of life (QoL), quality of care, and healthcare costs. We evaluated such effects in patients with advanced gastric cancer. METHODS: In this prospective, multicenter study, 186 advanced gastric cancer patients were randomized 1:1 to receive standard cancer care (SCC) plus on-demand EPC (standard arm) or SCC plus systematic EPC (interventional arm). Primary outcome was a change in QoL between randomization (T0) and T1 (12 weeks after T0) in the Trial Outcome Index (TOI) scores evaluated through the Functional Assessment of Cancer Therapy-Gastric questionnaire. Secondary outcomes were patient mood, overall survival, and family satisfaction with healthcare and care aggressiveness. RESULTS: The mean change in TOI scores from T0 to T1 was - 1.30 (standard deviation (SD) 20.01) for standard arm patients and 1.65 (SD 22.38) for the interventional group, with a difference of 2.95 (95% CI - 4.43 to 10.32) (p = 0.430). The change in mean Gastric Cancer Subscale values for the standard arm was 0.91 (SD 14.14) and 3.19 (SD 15.25) for the interventional group, with a difference of 2.29 (95% CI - 2.80 to 7.38) (p = 0.375). Forty-three percent of patients in the standard arm received EPC. CONCLUSIONS: Our results indicated a slight, albeit not significant, benefit from EPC. Findings on EPC studies may be underestimated in the event of suboptimally managed issues: type of intervention, shared decision-making process between oncologists and PC physicians, risk of standard arm contamination, study duration, timeliness of assessment of primary outcomes, timeliness of cohort inception, and recruitment of patients with a significant symptom burden. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT01996540).

Progression-free Survival as a Surrogate End-point in Advanced Colorectal Cancer Treated with Antiangiogenic Therapies.

BACKGROUND: It is not clear if progression-free survival (PFS) is a good surrogate end-point for overall survival (OS) for metastatic colorectal cancer if antiangiogenic therapies are used. MATERIALS AND METHODS: We investigated randomized controlled trials testing antiangiogenic agents against chemotherapy. Log hazard ratios (HR) for PFS and OS were used to construct linear regression models. The surrogate threshold effect (STE) was calculated. RESULTS: Thirteen studies and 24 comparison arms were available, including 7,179 patients. This model returned a significant correlation between PFS and OS (R(2)=0.68, p<0.001) with an STE of 0.83. Analysis restricted to first-line gave similar results (R(2)=0.68, p<0.001, STE=0.75). CONCLUSION: There is a significant correlation between the effect of treatment on PFS and OS. PFS remains a good surrogate end-point for OS even if anti-angiogenic agents are used.

Genetic mechanisms in interval colon cancers.

BACKGROUND AND AIM: The factors underlying the development of interval colon cancers are not well defined and are likely heterogeneous. We sought to determine whether there are distinct molecular properties associated with interval colon cancers. METHODS: Colon cancers diagnosed within 5 years of a complete and well-prepped colonoscopic examination were identified over a 7-year period at a single institution. The clinical and pathological features of the tumors were defined. Analysis of DNA mismatch repair (MMR) and genotyping of a panel of oncogenes associated with colon cancer were performed. RESULTS: Forty-two interval colon cancers were diagnosed at an average age of 70 years. 69 % of tumors were located in the right colon. 41 % of tumors exhibited DNA microsatellite instability (MSI). Loss of staining of DNA MMR proteins by immunohistochemistry (IHC) was confirmed in 82 % of the MSI-positive tumors. Among tumors with abnormal MSI and IHC, 54 % exhibited somatic methylation of the MLH1 promoter, but the remaining 43 % exhibited molecular features indicative of underlying Lynch syndrome (LS). The frequency of somatic mutations in the KRAS, BRAF, NRAS, and PIK3CA oncogenes was similar between interval cancer cases and controls. CONCLUSIONS: Interval colon cancers are not distinguished by the activation of the KRAS, NRAS, BRAF, or PIK3CA oncogenic pathways. However, MSI pathway defects are present in a significant proportion of interval colon cancers. Underlying LS may explain nearly half of these MSI-positive cases, and the remaining cases appear to represent sporadic serrated pathway tumors.

Severe thrombocytopenia after trastuzumab retreatment: a case report.

BACKGROUND: Trastuzumab prolongs survival of human epidermal growth factor receptor 2-positive breast cancer patients in both the adjuvant and metastatic settings. Currently toxicity data are not available on retreatment of metastatic breast cancer patients who relapse after adjuvant trastuzumab. We report one patient with metastatic breast cancer who developed acute thrombocytopenia after trastuzumab infusion. This patient had trastuzumab treatment in the adjuvant setting. CASE PRESENTATION: A 70-year-old Caucasian woman received a diagnosis of metastatic breast cancer four years after her initial diagnosis of locally advanced, hormone receptors-positive, human epidermal growth factor receptor 2-positive breast cancer. Trastuzumab retreatment was planned. Less than 24 hours after trastuzumab infusion, the patient was admitted to the hospital for the appearance of diffuse petechial hemorrhages and ecchymosis. The patient was confirmed to have a severe trastuzumab-induced thrombocytopenia. A rapid and complete recovery was observed after high-dose intravenous corticosteroids and immunoglobulin. No trastuzumab retreatment was attempted. CONCLUSION: Among the reported cases of trastuzumab-induced thrombocytopenia, this is the first report in the literature occurring in a patient retreated with trastuzumab after adjuvant therapy.

Molecular and genetic bases of pancreatic cancer.

Pancreatic cancer remains a formidable challenge for oncologists and patients alike. Despite intensive efforts, attempts at improving survival in the past 15 years, particularly in advanced disease, have failed. This is true even with the introduction of molecularly targeted agents, chosen on the basis of their action on pathways that were supposedly important in pancreatic cancer development and progression: indeed, with the notable exception of the epidermal growth factor receptor (EGFR) inhibitor erlotinib, that has provided a minimal survival improvement when added to gemcitabine, other agents targeting EGFR, matrix metallo-proteases, farnesyl transferase, or vascular endothelial growth factor have not succeeded in improving outcomes over standard gemcitabine monotherapy for a variety of different reasons. However, recent developments in the molecular epidemiology of pancreatic cancer and an ever evolving understanding of the molecular mechanisms underlying pancreatic cancer initiation and progression raise renewed hope to find novel, relevant therapeutic targets that could be pursued in the clinical setting. In this review we focus on molecular epidemiology of pancreatic cancer, epithelial-to-mesenchymal transition and its influence on sensitivity to EGFR-targeted approaches, apoptotic pathways, hypoxia-related pathways, developmental pathways (such as the hedgehog and Notch pathways), and proteomic analysis as keys to a better understanding of pancreatic cancer biology and, most importantly, as a source of novel molecular targets to be exploited therapeutically.

Emerging pathways and future targets for the molecular therapy of pancreatic cancer.

INTRODUCTION: Pancreatic cancer treatment remains a challenge for clinicians and researchers. Despite undisputable advances in the comprehension of the molecular mechanisms underlying cancer development and progression, early disease detection and clinical management of patients has made little, if any, progress in the past 20 years. Clinical development of targeted agents directed against validated pathways, such as the EGF/EGF receptor axis, the mutant KRAS protein, MMPs, and VEGF-mediated angiogenesis, alone or in combination with gemcitabine-based standard chemotherapy, has been disappointing. AREAS COVERED: This review explores the preclinical rationale for clinical approaches aimed at targeting the TGF-ß, IGF, Hedgehog, Notch and NF-κB signaling pathways, to develop innovative therapeutic strategies for pancreatic cancer. EXPERT OPINION: Although some of the already clinically explored approaches (particularly EGFR and KRAS targeting) deserve further clinical consideration, by employing more innovative and creative clinical trial designs than the gemcitabine-targeted agent paradigm that has thus far invariably failed, the targeting of emerging and relatively unexplored signaling pathways holds great promise to increase our understanding of the complex molecular biology and to advance the clinical management of pancreatic cancer.

Fixed-dose-rate gemcitabine: a viable first-line treatment option for advanced pancreatic and biliary tract cancer.

BACKGROUND: We have already reported on fixed-dose-rate gemcitabine (FDR-Gem) in advanced, inoperable pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancer (BTC) in the context of a formal phase II study; building on that experience, we have now expanded the study to reach a cumulative accrual of 106 patients. METHODS: One hundred six patients (PDAC/BTC, 75/31) were treated with weekly FDR-Gem (1,000 mg/m(2) infused at 10 mg/m(2) per minute). Patient characteristics included: male-to-female ratio, 0.83; median age, 63 years (range, 28-82); metastatic disease in 66% of patients; and an Eastern Cooperative Oncology Group performance status (ECOG PS) score of 0-1 in 81% of patients. RESULTS: The median and total number of treatment weeks delivered were 8 (range, 2-22) and 1,154, respectively. Thirteen percent of patients achieved an objective response, 42% experienced a positive clinical benefit response, and 54% achieved a >50% reduction in serum cancer antigen (CA)19.9 levels. The median progression-free survival (PFS) and overall survival (OS) times for the entire population were 4.4 months (95% confidence interval [CI], 3.5-5.1 months) and 7.7 months (95% CI, 6.3-8.8 months), respectively, with 20% of patients alive at 1 year. On multivariate analysis, a CA19.9 reduction >50% and baseline ECOG PS score of 0 were the only independent predictors of PFS and OS, respectively. Treatment was well tolerated, with grade 3-4 neutropenia in 47 of 1,154 treatment weeks (4.1%), and grade 3 anemia and thrombocytopenia in 8 of 1,154 (0.7%) and 16 of 1,154 (1.4%) treatment weeks, respectively. CONCLUSIONS: Currently available evidence, including this updated analysis, supports the use of FDR-Gem as a first-line option in advanced PDAC, and possibly in BTC, patients and prompts the continued evaluation of this approach in combination regimens.

Deficient DNA mismatch repair is common in Lynch syndrome-associated colorectal adenomas.

Lynch syndrome is caused by germline mutations in DNA mismatch repair (MMR) genes. Both microsatellite instability (MSI) testing and immunohistochemical analyses (IHC) of colon cancers are valuable diagnostic strategies for Lynch syndrome. We sought to determine whether these markers of MMR deficiency were also detectable in pre-cancerous colorectal adenomas. Fifteen subjects with a germline MMR gene mutation who had 44 adenomas removed during surveillance colonoscopy were identified. MSI testing and IHC for MLH1, MSH2, and MSH6 were performed. MSI was detected in 23 adenomas. There was a significant association between MSI and high-grade dysplasia (P = 0.006) and distal location (P = 0.0008). Loss of MMR protein by IHC was detected in 31 adenomas. A significant association was observed between loss of staining by IHC and high-grade dysplasia (P = 0.04). Among the 40 adenomas in which both MSI tests and IHC were performed, the presence of a germline mutation correlated with an abnormal MSI result in 58% of cases, an abnormal IHC result in 70% of cases, and either an abnormal MSI or IHC result in 73% of cases. The combination of MSI and IHC testing in colorectal adenomas is a sensitive screen for the detection of Lynch syndrome and may be particularly useful when Lynch syndrome is suspected and adenomatous polyps are the only tissues available for analysis.

A phase II study of biweekly paclitaxel (P) and gemcitabine (G), followed by maintenance weekly paclitaxel in elderly patients with advanced non-small cell lung cancer (NSCLC).

BACKGROUND: This phase II study was conducted to evaluate the efficacy and safety of a novel combination of paclitaxel (P) and gemcitabine (G) in an every 2 weeks schedule followed by weekly paclitaxel (P) as first-line treatment in elderly patients with locally advanced or metastatic NSCLC. METHODS: Elderly patients (> or =65 years of age) with 1997 TNM stage IIIB (pleural effusion)/stage IV NSCLC, performance status (PS) of 0-2 and normal organ function were eligible. Therapy consisted of P at 150 mg/m(2) and G at 2000 mg/m(2) administered every 2 weeks for 3 cycles followed, in progression-free patients, by P at 80 mg/m(2) every week for 6 consecutive weeks every 8 weeks for 2 cycles. RESULTS: Fifty-three eligible patients were enrolled: M/F 51/2; stage IIIB/IV 8/45; PS 0, 40%, PS 1 51%, PS 2 9%; median age, 73 years (range 67-82). The overall response rate was 32% (95% confidence interval [CI]: 19-45). The median overall survival was 7 months (95% CI: 5-9); the median progression-free survival was 5 months (95% CI: 3-6); and the 1- and 2-year survivals were 28.3% and 10.1%, respectively. Both phases of the treatment protocol were well tolerated. CONCLUSIONS: Biweekly P/G followed by weekly P is well tolerated and active as first-line therapy for elderly NSCLC patients.

Aromatase inhibitors in post-menopausal metastatic breast carcinoma.

To summarise the advances in the hormonal treatment of post-menopausal metastatic breast cancer, this paper reviews the published literature regarding the randomised trials comparing aromatase inhibitors (AIs) versus tamoxifen as a first-line therapeutic choice, or AIs versus megestrole acetate (MEG) as a second-line option. The pooled analysis of these authors on AI versus MEG as a second-line option for post-menopausal metastatic breast cancer suggested that AIs do not add any significant benefit over MEG in terms of overall response rate (ORR) and time to progression. According to the Cochrane Database, use of an AI as a second-line therapy versus any other endocrine therapy (mostly MEG) has shown a significant benefit in terms of overall survival, but not for progression-free survival, clinical benefit (CB) or ORR. Concerning the authors' comparisons between AIs versus tamoxifen as a first-line endocrine option in post-menopausal women with metastatic breast carcinoma, AIs seem to be superior to tamoxifen, with a significant benefit in terms of ORR, CB and time to progression being observed in favour of AIs over tamoxifen with fixed effects estimates. According to the Cochrane Database, there was an advantage to the use of AIs over tamoxifen in terms of progression-free survival and CB, but not for overall survival or ORR. With regards to toxicity, AIs show similar levels of hot flushes and arthralgia, increased risks of nausea, diarrhoea and vomiting, but a decreased risk of vaginal bleeding and thromboembolic events compared with other endocrine therapies. Weight gain, dyspnoea and peripheral oedema seem to be more frequent with MEG. At present, there is no proved overall survival difference in patients who are treated first with an AI and then with tamoxifen compared with the opposite sequence. In the metastatic setting, results are limited and are based on retrospective analyses.

Gemcitabine-based combinations for inoperable pancreatic cancer: have we made real progress? A meta-analysis of 20 phase 3 trials.

BACKGROUND: Several attempts have been made at improving the efficacy of gemcitabine in advanced pancreatic cancer by combining it with other chemotherapeutic or molecularly targeted agents. However, randomized trials have produced conflicting results. METHODS: All prospective, randomized, phase 3 trials that compared single-agent gemcitabine with gemcitabine-based combinations were considered eligible for the current analysis. A literature-based meta-analysis was performed, event-based relative risk ratios with 95% confidence intervals were derived through both a fixed-effect model approach and a random-effect model approach, and overall survival (OS) was explored as the primary endpoint. To estimate the magnitude of the eventual benefit, absolute differences and the number of patients needed to treat (NNT) for 1 patient to benefit were calculated. A sensitivity analysis for OS was performed according to the type of agent used in combination with gemcitabine. RESULTS: Twenty trials that involved 6,296 patients were identified. No significant differences in the primary endpoint were observed in the overall population or in the sensitivity analysis. Conversely, a significant advantage was evident with regard to both progression-free survival (PFS) and the overall response rate (ORR) in the overall population, with an absolute benefit of 2.6% (NTT = 39 patients) and 3.0% (NNT = 33 patients). Platinum combinations led to the greatest absolute benefits for PFS and ORR compared with single-agent gemcitabine (10% and 6.5%, respectively), but this did not result in an OS benefit. Improvement in PFS, but not in the ORR, was correlated with an improvement in OS. CONCLUSIONS: Single-agent gemcitabine remains the standard of care for patients with advanced pancreatic cancer. However, platinum/gemcitabine combinations appeared to improve PFS and the ORR and, thus, may be considered in selected patients.

Gefitinib reverses TRAIL resistance in human bladder cancer cell lines via inhibition of AKT-mediated X-linked inhibitor of apoptosis protein expression.

In a previous study, we found that the small-molecule epidermal growth factor receptor (EGFR) inhibitor gefitinib (ZD1839, Iressa) blocked cell proliferation at biologically relevant concentrations in approximately one third (6 of 17) of human bladder cancer cell lines examined. Here, we studied the effects of gefitinib on apoptosis in a representative subset of the same panel of cells. The drug had modest effects on DNA fragmentation as a single agent at concentrations that produced strong growth inhibition (< or =1 micromol/L) and also failed to promote apoptosis induced by conventional chemotherapeutic agents (gemcitabine and paclitaxel). However, gefitinib did interact with recombinant human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to induce high levels of apoptosis in gefitinib-responsive but not gefitinib-unresponsive lines. The molecular mechanisms involved down-regulation of active AKT and X-linked inhibitor of apoptosis protein (XIAP) expression and were mimicked by chemical inhibitors of the phosphatidylinositol 3-kinase/AKT pathway but not of the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase/ERK pathway. Furthermore, direct small interfering RNA-mediated knockdown of AKT resulted in down-regulation of XIAP and TRAIL sensitization, and knockdown of XIAP itself was sufficient to reverse TRAIL resistance. Together, our results show that EGFR pathway activation limits TRAIL-induced apoptosis via an AKT- and XIAP-dependent mechanism in EGFR-dependent human bladder cancer cells, providing the conceptual framework for a further evaluation of the combination in relevant preclinical in vivo models.

Molecular correlates of gefitinib responsiveness in human bladder cancer cells.

We characterized the effects of the small molecule epidermal growth factor receptor (EGFR) inhibitor gefitinib (ZD1839, Iressa) on cell proliferation in a panel of 17 human bladder cancer cell lines. Gefitinib inhibited DNA synthesis in a concentration-dependent fashion in 6 of 17 lines. Growth inhibition was associated with p27(Kip1) accumulation and decreased cyclin-dependent kinase 2 activity. Gefitinib also inhibited baseline EGFR, AKT, and extracellular signal-regulated kinase (ERK) phosphorylation in the EGFR-dependent cells maintained in serum-free medium, whereas it had no effect on baseline EGFR or ERK phosphorylation in the EGFR-independent cells. Analyses of candidate markers of EGFR dependency revealed that the gefitinib-sensitive cells expressed higher surface EGFR levels than the gefitinib-resistant lines. Gefitinib-sensitive cells generally expressed higher levels of E-cadherin and lower levels of vimentin than the gefitinib-resistant cells, but these correlations were not perfect, suggesting that these markers of epithelial-mesenchymal transition cannot be used by themselves to prospectively predict EGFR-dependent growth. Together, our results show that bladder cancer cells are markedly heterogeneous with respect to their sensitivity to EGFR antagonists. Although surface EGFR levels and epithelial-mesenchymal transition status seem to roughly correlate with responsiveness, they cannot be used by themselves to identify bladder tumors that will be sensitive to EGFR-directed therapy. However, comparing levels of p27(Kip1) or DNA synthesis before and after gefitinib exposure does identify the drug-sensitive cells.