Naveed Sarwar

Phosphorylation of human estrogen receptor α at serine 118 by two distinct signal transduction pathways revealed by phosphorylation-specific antisera

Estrogen receptor α (ERα) is a transcription factor that regulates expression of target genes in a ligand-dependent manner. Activation of gene expression is mediated by two transcription activation functions AF-1 and AF-2, which act in a promoter- and cell-specific manner. Whilst AF-2 activity is regulated by estrogen (E2) binding, the activity of AF-1 is additionally modulated by phosphorylation at several sites. One of these phosphorylation sites, serine 118 (S118) is of particular interest as its mutation significantly reduces ERα activity. Previous studies have shown that S118 can be phosphorylated by the ERK1/2 mitogen activated protein kinases (MAPK) and by the cyclin-dependent protein kinase Cdk7. In this study we use antisera that specifically recognize ERα phosphorylated at S118 to demonstrate that MAPK phosphorylates S118 in a ligand-independent manner, whereas Cdk7 mediates E2-induced phosphorylation of S118. E2 stimulation of S118 phosphorylation was observed within 10 min of its addition and was maximal at 10−7 M E2. S118 phosphorylation was maximal at 30 min but then declined, such that by 180 min following E2 addition little S118 phosphorylation was evident. S118 phosphorylation was also induced by the partial estrogen antagonist 4-hydroxytamoxifen, but not by the complete antagonist ICI 182, 780. S118 phosphorylation upon addition of the MAPK inducers EGF or PMA followed the expected time courses. Finally, we show that ERα is phosphorylated at S118 in vivo using immunoblotting of extracts prepared from a series of ERα-positive breast tumours.

The safety and efficacy of sunitinib before planned nephrectomy in metastatic clear cell renal cancer

Background: The safety and efficacy of upfront sunitinib, before nephrectomy in metastatic clear cell renal cancer (mCRC), has not been prospectively evaluated. Methods: Two prospective single-arm phase II studies investigated either two cycles (study A: n = 19) or three cycles (study B: n = 33) of sunitinib before nephrectomy in mCRC. Results: Overall, 38 of 52 (73%) of patients obtained clinical benefit (by RECIST) before surgery. The partial response rate of the primary tumour was 6% [median reduction in longest diameter of 12% (range 8%−35%)]. No patients became ineligible due to local progression of disease. A nephrectomy was carried out in 37 (71%) of patients. Necrosis (>50%) was a prominent feature at nephrectomy in 49%. Surgical complications (Clavien–Dindo classification) occurred in 10 (27%) patients, including one death (3%). The median blood loss and surgical time were 725 (90–4200) ml and 189 (70–420) min, respectively. The median progression-free survival was 8 months (95% confidence interval 6–15 months). A comparison of two versus three pre-surgery cycles showed no significant difference in terms of surgical complications or efficacy. Conclusions: Nephrectomy after upfront sunitinib can be carried out safely. It obtains control of disease. Randomised studies are required to address if this approach is beneficial.

The Outcome of Patients Treated with Sunitinib Prior to Planned Nephrectomy in Metastatic Clear Cell Renal Cancer

BACKGROUND The role of cytoreductive nephrectomy in metastatic clear cell renal cell carcinoma (ccRCC) is controversial. OBJECTIVE To determine the outcome of patients with metastatic ccRCC who receive sunitinib prior to planned nephrectomy. DESIGN, SETTING, AND PARTICIPANTS The study combined the data from two prospective phase 2 studies that assessed upfront sunitinib (12-16 wk) prior to nephrectomy in previously untreated patients with metastatic renal cell carcinoma (RCC). Sunitinib was discontinued during the perioperative period (median: 29 d). INTERVENTION Sunitinib 50mg in six weekly cycles (4 wk on, 2 wk off). MEASUREMENTS Progression-free (PFS) and overall survival (OS) using the Kaplan-Meier method. RESULTS AND LIMITATIONS Twenty-one patients (32%) had Memorial Sloan-Kettering Cancer Centre (MSKCC) poor-risk disease; 45 (68%) had intermediate-risk disease. Nephrectomy was not performed in 19 (29%), most commonly due to disease progression (n = 12). The PFS for the cohort was 6.3 mo (95% confidence interval [CI], 5.1-8.5). Seventeen (36%) patients progressed during the treatment break, 13 (76%) of whom stabilised upon reinitiating of sunitinib. The OS for the cohort was 15.2 mo (95% CI, 10.3-NA). The OS for the intermediate MSKCC risk group was significantly longer than that for the poor-risk group (26.0 mo [95% CI, 13.6-NA] and 9.0 mo [95% CI, 5.8-20.5], respectively; p < 0.01). In multivariate analysis, progression of disease prior to planned nephrectomy (hazard ratio [HR]: 5.34; 95% CI, 3.17-13.27), high Fuhrman grade (HR 3.27; 95% CI, 1.38-7.72), and MSKCC poor risk at diagnosis (HR 4.75; 95% CI, 2.05-11.02) were associated with short survival (p < 0.01). However, in the absence of randomised studies it is not possible to determine if this approach is beneficial. CONCLUSIONS Upfront sunitinib prior to planned nephrectomy in intermediate-risk disease is associated with a median survival of >2 yr despite frequent progression during treatment break. Progression in metastatic sites prior to planned surgery and MSKCC poor-risk disease was associated with a poor outcome.

Phosphorylation of Estrogen Receptor-α at Ser167 Is Indicative of Longer Disease-Free and Overall Survival in Breast Cancer Patients

Purpose: Ser167 was first identified as a major phosphorylation site of the estrogen receptor -α (ER) positive in the MCF7 breast cancer cell line. Subsequent studies have shown that Ser167 phosphorylation is important in the regulation of ER activity and have identified p90RSK and AKT as protein kinases that phosphorylate Ser167. The purpose of this study was to determine the importance of Ser167 phosphorylation in breast cancer progression. Experimental Design: Immunohistochemical staining of primary breast cancer biopsies (n = 290) was carried out using antibodies specific for ER phosphorylated at Ser167 and for phosphorylated p44/p42 mitogen-activated protein kinase (MAPK), phosphorylated p90RSK, and phosphorylated AKT. Results: In ER-positive breast cancer patients, Ser167 phosphorylation was associated with low tumor grade (P = 0.011), lymph node negativity (P = 0.034), and relapse-free (P = 0.006) and overall (P = 0.023) survival. Further, Ser167 phosphorylation was strongly associated with phosphorylated p90RSK (P < 0.001), previously shown to phosphorylate Ser167 in vitro, as well as being associated with phosphorylated MAPK (P < 0.0005). The activities of both kinases also seemed to be indicative of better prognosis. There was, however, no association between HER2 positivity and Ser167 phosphorylation nor were the activities of MAPK or p90RSK associated with HER2 status, suggesting that other cell surface receptors may be important in regulating these activities in breast cancer. Conclusions: These findings show that phosphorylation at Ser167 of ER predicts for likelihood of response of ER-positive breast cancer patients to endocrine therapies.

Safety and Efficacy of Pazopanib Therapy Prior to Planned Nephrectomy in Metastatic Clear Cell Renal Cancer

Importance The role of cytoreductive nephrectomy in patients with metastatic renal cancer in the era of targeted therapy is uncertain. Objective To establish the safety and efficacy of upfront pazopanib therapy prior to cytoreductive nephrectomy in previously untreated patients with metastatic clear cell renal cancer. Design, Setting, and Participants Single-arm phase 2 study of 104 previously untreated patients with metastatic clear cell renal cancer recruited between June 2008 and October 2012 at cancer treatment centers with access to nephrectomy services. The minimum follow-up was 30 months. Interventions Patients received 12 to 14 weeks of preoperative pazopanib therapy prior to planned cytoreductive nephrectomy and continued pazopanib therapy after surgery. Treatment was stopped at disease progression. Main Outcomes and Measures The primary end point was clinical benefit (using Response Evaluation Criteria in Solid Tumors, version 1.1) prior to surgery (at 12-14 weeks). Secondary end points included surgical complications, progression-free survival (PFS), overall survival (OS), and biomarker analysis. Results Of 104 patients recruited, 100 patients were assessable for clinical benefit prior to planned nephrectomy; 80 of 104 (76.9%) were men; median [interquartile range] age, 64 [56-71] years). Overall, 84 of 100 (84% [95% CI, 75%-91%]) gained clinical benefit before planned nephrectomy. The median reduction in the size of the primary tumor was 14.4% (interquartile range, 1.4%-21.1%). No patients were unable to undergo surgery as a result of local progression of disease. Nephrectomy was performed in 63 (61%) of patients; 14 (22%) reported surgical complications. The 2 most common reasons for not undergoing surgery were progression of disease (n = 13) and patient choice (n = 9). There was 1 postoperative surgical death. The median PFS and OS for the whole cohort were 7.1 (95% CI, 6.0-9.2) and 22.7 (95% CI, 14.3-not estimable) months, respectively. Patients with MSKCC poor-risk disease or progressive disease prior to surgery had a poor outcome (median OS, 5.7 [95% CI, 2.6-10.8] and 3.9 [95% CI, 0.5-9.1] months, respectively). Surgical complications were observed in 14 (22%) of the nephrectomies. Biomarker analysis from sequential tissue samples revealed a decrease in CD8 expression (20.00 vs 13.75; P = .05) and significant reduction in expression of von Hippel-Lindau tumor suppressor (100 vs 40; P < .001) and C-MET (300 vs 100; P < .001) and increased programmed cell death ligand 1 expression (0 vs 1.5; P < .001) in the immune component. No on-treatment biomarker correlated with response. Conclusions and Relevance Nephrectomy after upfront pazopanib therapy could be performed safely and was associated with good outcomes in patients with intermediate-risk metastatic clear cell renal cancer.

The safety and efficacy of sunitinib prior to planned nephrectomy in metastatic clear cell renal cancer.

427 Background: The safety and efficacy of upfront pazopanib, prior to nephrectomy in metastatic clear cell renal cancer (mCRC), has not been prospectively evaluated. The toxicity profile of pazopanib potentially makes it an attractive agent in this setting. METHODS A single arm phase II study (PANTHER 2009-016675-29) evaluated 12-14 weeks of pazopanib prior to planned nephrectomy in untreated patients with metastatic clear cell renal cancer. Patients had MSKCC intermediate and poor risk disease. Pazopanibwas stopped for a minimum of 16 days during nephrectomy. FDG-PET and DCEMRI were performed on a subgroup of patients. The study follows a Simon 2 stage design and we present the results of the initial stage(n=34). RESULTS Overall 30 (88%) of patients obtained clinical benefit (by RECIST) prior to surgery. The partial response rate of the primary tumor was 21% by RECIST. No patients became inoperable due to local progression of disease. A nephrectomy was performed in 25 (74%) of patients. The reasons for not having surgery were patient choice (n=5) and progression of disease (n=4). Delayed wound healing, a post operative bleed and a post operative death occurred in 1patient each (4%). The median blood loss, hospital stay and surgical time were 350mls, 7 days and 180mins respectively. FDG-PET and DCE MRI responses were reported. CONCLUSIONS This interim analysis suggest nephrectomy after upfront pazopanib can be performed safely in mRCC and obtains control of disease in the majority of patients.

An indirect comparison of the toxicity of sunitinib and pazopanib in metastatic clear cell renal cancer

BACKGROUND Both sunitinib and pazopanib are widely used as first line therapy in metastatic renal cancer (mRCC). The efficacy of these agents appears similar but they may have distinct toxicity profiles. In this study we compare the severity of symptomatic and asymptomatic toxicity associated with sunitinib and pazopanib. METHODS Two sequential prospective single arm phase II studies investigated either 12 weeks of sunitinib (n=43) or pazopanib (n=34) prior to nephrectomy in untreated mRCC. Toxicity was defined as either symptomatic (hand and foot syndrome, mucositis, nausea, fatigue, diarrhoea, oedema, headache, pain, anorexia and change in taste) or asymptomatic (liver toxicity or haematological toxicity). Pazopanib (800 mg once daily (OD)) and sunitinib (50 mg 4/2) were given. Regular Common Toxicity Criteria (CTC) toxicity assessment was performed during the first 12 weeks of therapy. RESULTS There was no significant difference in the overall number of toxic events (grade 1-4) for sunitinib and pazopanib (mean number of toxic events/patients: 1.97 versus 1.96: p>0.05). Increased grade 2-4 symptomatic toxicity events occurred with sunitinib (hazard ratio (HR) 1.67 [95% confidence interval (CI): 1.11-2.56] p<0.03). Sunitinib was associated with an increased grade 2-4 mucositis (16% versus 0% p=0.02) and fatigue (42% versus 15% p=0.01). Pazopanib was associated with more frequent grade 1 diarrhoea (39% versus 12%: p=0.03). Dose reductions for symptomatic toxicity occurred more frequently with sunitinib (26% versus 6% p<0.05). There was no difference in the occurrence of asymptomatic toxicity. CONCLUSION This indirect analysis suggests sunitinib and pazopanib have distinct toxicity profiles which may help guide patients choice. Further comparative data from randomised trials are awaited.

The Effect of Sunitinib on Immune Subsets in Metastatic Clear Cell Renal Cancer

Background: Sunitinib is standard first-line therapy for metastatic clear cell renal cancer (MCRC). It is associated with leucopenia; however, its effects on specific immune cell subsets are unclear. Alterations in immune cell subsets may contribute to tumour progression. Methods: Lymphocyte subsets (CD3, 4, 8, 19 and 56) were measured in 43 untreated MCRC patients who received sunitinib. The protocol included a structured treatment interruption of 5 weeks. Cell populations were measured at specific time points during sunitinib treatment and the treatment break. Results: Sunitinib was associated with significant declines in total leucocyte (–48%), neutrophil (–62%), CD3 total T cell (–31%) and CD4 counts (32%; p < 0.05). There was no significant change in CD19 B lymphocyte, CD8 or CD56 natural killer cells. During the sunitinib-free interval, all parameters recovered to baseline. No patients developed opportunistic infections or neutropenic sepsis. The level of specific immune subsets at presentation or occurrence of a fall in specific counts had an effect on progression-free survival (p > 0.05). Conclusions: Sunitinib is associated with reversible inhibition of specific lymphocyte subsets which has implications for the immunological control of MCRC and its use in combination with other agents. Despite suppressive effects, there was no evidence of predisposition to immune suppressive-related infection.

Circulating cell free DNA in the diagnosis of trophoblastic tumors

Gestational trophoblastic neoplasia (GTN) represents a group of diseases characterized by production of human chorionic gonadotropin (hCG). Since non-gestational tumors may occasionally secrete hCG, histopathological diagnosis is important for appropriate clinical management. However, a histopathological diagnosis is not always available. We therefore investigated the feasibility of extracting cell free DNA (cfDNA) from the plasma of women with GTN for use as a “liquid biopsy” in patients without histopathological diagnosis. cfDNA was prepared from the plasma of 20 women with a diagnosis of GTN and five with hCG-secreting tumors of unknown origin. Genotyping of cfDNA from the patient, genomic DNA from her and her partner and DNA from the tumor tissue identified circulating tumor DNA (ctDNA) (from 9% to 53% of total cfDNA) in 12 of 20 patients with GTN. In one case without a tissue diagnosis, ctDNA enabled a diagnosis of GTN originating in a non-molar conception and in another a diagnosis of non-gestational tumor, based on the high degree of allelic instability and loss of heterozygosity in the ctDNA. In summary ctDNA can be detected in the plasma of women with GTN and can facilitate the diagnosis of both gestational and non-gestational trophoblastic tumors in cases without histopathological diagnosis.

A phase Ib study investigating the combination of everolimus and dovitinib in vascular endothelial growth factor refractory clear cell renal cancer

BACKGROUND Everolimus (mammalian target of rapmaycin (mTOR) inhibitor) and dovitinib (vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) inhibitor) demonstrate activity in metastatic clear cell renal cancer. The combination of these agents has a broad spectrum of relevant activity. The combination is explored in this phase Ib study. METHODS Patients with metastatic clear cell renal cancer who have failed VEGF targeted therapy were eligible. Up to four cohorts of three to six patients (3+3 design) were treated with escalating doses of everolimus and dovitinib. Dose-limiting toxicities (DLTs) were assessed to determine the maximum tolerated dose (MTD). An expansion cohort (n=15) was investigated to obtain additional efficacy information. Sequential fluorodeoxyglucose positron emission tomography (FDG-PET) was used as a surrogate marker of response. RESULTS Overall 18 patients were recruited into the study. Fifteen patients received the MTD, which was everolimus 5mg orally (PO) once daily (OD) and dovitinib 200mg PO day 1-5/7. The MTD was associated with toxicity, which included fatigue, mucositis and diarrhoea in 73%, 53% and 53% (Common Toxicity Criteria (CTC) grade 1-4) of patients, respectively. Frequent biochemical abnormalities occurred (such as hypertriglyceridaemia in 67%). Higher doses of the combination were not tolerable due to grade 3 fatigue in 2/3 patients and grade 3 nausea in 1/3 patients within 1 month of therapy. The response rate at the MDT was 1/15 (7%) while the progression free survival for the MTD was 7 months (95% confidence interval (CI) 2.2-11 months). Pharmacokinetic data at the MTD showed stable kinetics with time. CONCLUSION Dovitinib and everolimus had modest activity, but did not meet all of the planned efficacy end-points. Fatigue was the dose limiting toxicity.