Project description:BackgroundSunitinib, a multitargeted tyrosine-kinase inhibitor, which is approved by both US and European Commission regulatory agencies for clinical use, extends survival of patients with metastatic renal-cell carcinoma and gastrointestinal stromal tumours, but concerns have arisen about its cardiac safety. We therefore assessed the cardiovascular risk associated with sunitinib in patients with metastatic gastrointestinal stromal tumours.MethodsWe retrospectively reviewed all cardiovascular events in 75 patients with imatinib-resistant, metastatic, gastrointestinal stromal tumours who had been enrolled in a phase I/II trial investigating the efficacy of sunitinib. The composite cardiovascular endpoint was cardiac death, myocardial infarction, and congestive heart failure. We also examined sunitinib's effects on left ventricular ejection fraction (LVEF) and blood pressure. We investigated potential mechanisms of sunitinib-associated cardiac effects by studies in isolated rat cardiomyocytes and in mice.FindingsEight of 75 (11%) patients given repeating cycles of sunitinib in the phase I/II trial had a cardiovascular event, with congestive heart failure recorded in six of 75 (8%). Ten of 36 (28%) patients treated at the approved sunitinib dose had absolute LVEF reductions in ejection fraction (EF) of at least 10%, and seven of 36 (19%) had LVEF reductions of 15 EF% or more. Sunitinib induced increases in mean systolic and diastolic blood pressure, and 35 of 75 (47%) individuals developed hypertension (>150/100 mm Hg). Congestive heart failure and left ventricular dysfunction generally responded to sunitinib being withheld and institution of medical management. Sunitinib caused mitochondrial injury and cardiomyocyte apoptosis in mice and in cultured rat cardiomyocytes.InterpretationLeft ventricular dysfunction might be due, in part, to direct cardiomyocyte toxicity, exacerbated by hypertension. Patients treated with sunitinib should be closely monitored for hypertension and LVEF reduction, especially those with a history of coronary artery disease or cardiac risk factors.
Project description:Recent clinical trials have investigated the benefit of combining tyrosine kinase inhibitors (TKIs) and cytoreductive nephrectomy (CN) in patients with metastatic renal cell carcinoma. Our goal is to determine whether the perioperative use of TKIs increases the postoperative morbidity following CN in renal cell carcinoma patients. We identified 627 patients with Stage IV renal cell carcinoma who underwent CN from 2007-2010 utilizing the SEER-Medicare database. Eighty-two patients treated with TKIs were matched (3:1) to 246 controls. We calculated 30- and 90-day incidence rates of postoperative complications and mortality. On unadjusted analysis, TKI use prior to CN was associated with higher overall complication rate within 30 days (HR?=?2.73, 95% CI: 1.09-6.8) after surgery. On multivariate analysis, perioperative TKI use was independently associated with higher risk for postoperative complications within 30 days (HR?=?2.93, 95% CI: 1.17-7.36), as well as 90 days (HR?=?1.84, 95% CI: 1.02-3.32) after nephrectomy. A higher Charlson comorbidity index also emerged to represent an independent risk factor for postoperative complications within 30 days (HR?=?2.41, 95% CI: 1.44-4.02) and 90 days (HR?=?2.23, 95% CI: 1.51-3.29) after nephrectomy. TKI treatment was not associated with an increased postoperative mortality at 30 and 90 days after surgery. Thus, TKI treatment was associated with an increased complication rate but not overall mortality following CN. Our results suggest that renal surgeons should be aware of possibly increased complications following CN in renal cell carcinoma patients, when TKI treatment is administered.
Project description:Epidermal growth factor receptor inhibition is a good target for the treatment of lung, colon, pancreatic and head and neck cancers. Epidermal growth factor receptor-tyrosine kinase inhibitor was first approved for the treatment of advanced lung cancer in 2002. Epidermal growth factor receptor-tyrosine kinase inhibitor plays an essential role in the treatment of cancer, especially for patients harbouring epidermal growth factor receptor activating mutation. Hence, skin toxicity is the most concerning issue for the epidermal growth factor receptor-tyrosine kinase inhibitor treatment. Skin toxicity is bothersome and sometimes affects the quality of life and treatment compliance. Thus, it is important for physicians to understand the background and how to manage epidermal growth factor receptor-tyrosine kinase inhibitor-associated skin toxicity. Here, the author reviewed the mechanism and upfront preventive and reactive treatments for epidermal growth factor receptor inhibitor-associated skin toxicities.
Project description:Personalized cancer medicine aims to accurately predict the response of individual patients to targeted therapies, including tyrosine kinase inhibitors (TKIs). Clinical implementation of this concept requires a robust selection tool. Here, using both cancer cell lines and tumor tissue from patients, we evaluated a high-throughput tyrosine kinase peptide substrate array to determine its readiness as a selection tool for TKI therapy. We found linearly increasing phosphorylation signal intensities of peptides representing kinase activity along the kinetic curve of the assay with 7.5-10??g of lysate protein and up to 400??M adenosine triphosphate (ATP). Basal kinase activity profiles were reproducible with intra- and inter-experiment coefficients of variation of <15% and <20%, respectively. Evaluation of 14 tumor cell lines and tissues showed similar consistently high phosphorylated peptides in their basal profiles. Incubation of four patient-derived tumor lysates with the TKIs dasatinib, sunitinib, sorafenib and erlotinib primarily caused inhibition of substrates that were highly phosphorylated in the basal profile analyses. Using recombinant Src and Axl kinase, relative substrate specificity was demonstrated for a subset of peptides, as their phosphorylation was reverted by co-incubation with a specific inhibitor. In conclusion, we demonstrated robust technical specifications of this high-throughput tyrosine kinase peptide microarray. These features required as little as 5-7??g of protein per sample, facilitating clinical implementation as a TKI selection tool. However, currently available peptide substrates can benefit from an enhancement of the differential potential for complex samples such as tumor lysates. We propose that mass spectrometry-based phosphoproteomics may provide such an enhancement by identifying more discriminative peptides.
Project description:To elucidate whether tyrosine kinase inhibitor (TKI) resistance in CML is associated with characteristic genomic alterations, we analyzed DNA samples from 45 TKI resistant CML patients with 250K single nucleotide polymorphism (SNP) arrays. From 20 patients, matched serial samples of pre-treatment and TKI resistance time points were available. 11 of the 45 TKI resistant patients had mutations of BCR-ABL1, including two T315I mutations. Besides known TKI resistance associated genomic lesions such as duplication of the BCR-ABL1 gene (n=8) and trisomy 8 (n=3), recurrent submicroscopic alterations including acquired uniparental disomy were detectable on chromosomes 1, 8, 9, 17, 19 and 22. On chromosome 22, newly acquired and recurrent deletions of the IGLC1 locus were detected in three patients, who had previously presented with lymphoid or myeloid blast crisis. This may support a hypothesis of TKI induced selection of subclones differentiating into immature B-cell progenitors as a mechanism of disease progression and evasion of TKI sensitivity. Keywords: SNP-chip
Project description:Gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, increases brain parenchymal extracellular fluid (ECF) accumulation of topotecan, a substrate of the ATP-binding cassette (ABC) transporters P-glycoprotein (Pgp/MDR-1) and breast cancer resistance protein (BCRP/ABCG2). The effect of modulating these transporters on topotecan penetration in gliomas has not been thoroughly studied. Thus, we performed intracerebral microdialysis on mice bearing orthotopic human gliomas (U87 and MT330) and assessed topotecan tumor ECF (tECF) penetration and the effect of gefitinib on topotecan tECF penetration and intratumor topotecan distribution. We found that topotecan penetration (P(tumor)) of U87 was 0.96 +/- 0.25 (n = 7) compared with that of contralateral brain (P(contralateral), 0.42 +/- 0.11, n = 5; P = 0.001). In MT330 tumors, P(tumor) (0.78 +/- 0.26, n = 6) and P(contralateral) (0.42 +/- 0.11, n = 5) also differed significantly (P = 0.013). Because both tumor models had disrupted blood-brain barriers and similar P(tumor) values, we used U87 and a steady-state drug administration approach to characterize the effect of gefitinib on topotecan P(tumor). At equivalent plasma topotecan exposures, we found that P(tumor) after gefitinib administration was lower. In a separate cohort of animals, we determined the volume of distribution of unbound topotecan in tumor (V(u,tumor)) and found that it was significantly higher in groups receiving gefitinib, implying that gefitinib administration leads to a greater proportion of intracellular topotecan. Our results provide crucial insights into the role that transporters play in central nervous system drug penetration and provide a better understanding of the effect of coadministration of transporter modulators on anticancer drug distribution within a tumor.