Brain metastases from renal cell carcinoma. Should we change the current standard?

Renal cell carcinoma (RCC) is one of the most common sources of brain metastases, with an incidence that varies widely from 4% to 48% according to different studies. In addition, asymptomatic metastases occur in up to 33% of patients with metastatic RCC, further complicating the decision-making process in this poor prognosis population. The purpose of this review is to cover in depth the present state of knowledge on the diagnosis and management of patients with brain metastases from RCC, in order to assess whether the current standard should be challenged. The existing systems to predict response and survival will be reviewed, as well as the available therapeutic options regarding local treatment and systemic therapy, all within the context of updated data from clinical trials. In this regard, the role of novel targeted agents for the treatment of brain metastases from RCC, such as the multi-targeted receptor tyrosine kinase inhibitors sunitinib and sorafenib, will be updated and discussed.     

舒尼替尼通过抑制 Akt／mTOR 信号通路诱导肾癌细胞自噬

目的：研究舒尼替尼引起的肾癌细胞出现细胞自噬的机制。方法：以肾癌细胞系ACHN细胞为细胞模型,利用3-(4,5-二甲基)-5-(3-羧甲基苯环)-2-(4-硫基苯)-2H 四唑盐复合物［3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium,innersalt,MTS］检测法观察舒尼替尼对ACHN 细胞活性的影响;应用RNA干扰技术敲降自噬相关蛋白Beclin1和微管相关蛋白1轻链3融合蛋白（microtubule associated protein 1 light chain 3 fusion protein, LC3）检测自噬与舒尼替尼引起的细胞凋亡。使用电子显微镜和荧光显微镜观察在舒尼替尼作用下自噬体的形成;蛋白质免疫印迹检测舒尼替尼对LC3-Ⅱ的积累,自噬相关信号通路蛋白激酶B(protein kinase B, PKB/Akt)、哺乳动物雷帕霉素受体( mammalian target of rapamycin, mTOR) 及聚腺苷二磷酸核糖聚合酶( poly ADP-ribose polymerase,PARP) 切割的变化和过量表达,以及敲降Akt检测诱导自噬的变化。结果: 舒尼替尼能显著抑制ACHN的细胞活性,这种作用具有时间和浓度依赖性;敲降自噬相关蛋白Beclin1和LC3减少自噬可改变舒尼替尼引起PARP的切割;透射和荧光显微镜观察结果表明,舒尼替尼引起细胞自噬体明显增加;蛋白质免疫印迹结果显示舒尼替尼增加自噬同时减少了Akt/mTOR的磷酸化。过量表达持续活化的Akt抑制了该化合物引起的自噬,而敲降Akt可促进自噬发生。mTOR抑制剂雷帕霉素能上调舒尼替尼引起的自噬并促进细胞活性的丢失。结论：舒尼替尼通过抑制Akt/mTOR信号通路促进肾癌细胞ACHN的自噬,其诱导的自噬与凋亡有关。     

Magnetic resonance imaging identifies early effects of sunitinib treatment in human melanoma xenografts

Background

Antiangiogenic treatment may change the tumor microenvironment and hence influence the effect of conventional therapies. The potential of diffusion weighted magnetic resonance imaging (DW-MRI) and dynamic contrast enhanced MRI (DCE-MRI) in assessing microenvironmental effects of sunitinib treatment was investigated in this preclinical study.

Methods

Sunitinib-treated and untreated A-07 tumors were subjected to DW-MRI and DCE-MRI, and parametric images of ADC and K^trans were produced. Microvascular density, hypoxic fraction, and necrotic fraction were assessed from immunohistochemical preparations, and tumor interstitial fluid pressure (IFP) was assessed with probe measurement.

Results

Sunitinib-treated tumors showed reduced microvascular density, increased hypoxic fraction, increased necrotic fraction, increased ADC, and reduced K^trans, but did not differ from untreated tumors in growth rate and IFP.

Conclusions

Sunitinib treatment affected the tumor microenvironment without affecting tumor size. DW-MRI and DCE-MRI were sensitive to the sunitinib-induced changes in the tumor microenvironment.

     

Evaluation of subchronic toxicity of SIM010603, a potent inhibitor of receptor tyrosine kinase,after 28-day repeated oral administration in SD rats and beagle dogs

SIM010603, a promising multi-targeted receptor tyrosine kinase (RTK) inhibitor, is now being considered for evaluation in phase clinical trial. In this work, the subchronic toxicity of SIM010603 in SD rats and beagle dogs have been characterized. Rats and dogs received SIM010603 orally (0–20 and 0–10 mg/kg/day, respectively) on a consecutive daily dosing schedule for 28 days following a 14 days recovery period. Sunitinib was used as a positive control. The No Observed Adverse Effect Level (NOAEL) of SIM010603 was 5 mg/kg/day for rats, and undefined for dogs. The treatment resulted in unscheduled mortality in dogs receiving 10 mg/kg of SIM010603 or Sunitinib. The adverse effects of SIM010603 on rats and dogs mainly included gastrointestinal toxicity, skeletal toxicity, myelosuppression, thymus atrophy, bronchopneumonia, cardiovascular dysfunction, and pancreatic toxicity. Similar observations have also been noted with this class of RTK signaling inhibitors and are consistent with pharmacologic perturbations of physiologic/angiogenic processes associated with the intended molecular targets. Most treatment-induced effects were reversible or showed ongoing recovery upon discontinuation of treatment. SIM010603 has shown comparable toxicity effect on beagle dogs, while better tolerability on SD rats when compared to Sunitinib.     

新型多聚体微泡携带舒尼替尼抑制人肾癌GRC-1细胞生长及促凋亡的实验研究

目的 观察新型多聚体微泡携带舒尼替尼对人肾癌GRC-1细胞生长及凋亡的影响.方法 将体外培养的人肾癌GRC-1细胞随机分为6组:空白对照组、单纯微泡组、单纯脂质体组、舒尼替尼组、新型多聚体微泡载舒尼替尼不联合超声组、新型多聚体微泡载舒尼替尼联合超声组.MTT法观察不同处理组细胞生存率,Sigma-FITC荧光染色及透射电镜检测细胞凋亡.结果 新型多聚体微泡载舒尼替尼联合超声组对人肾癌GRC-1细胞的生长抑制及促进凋亡作用强于其他处理组及对照组.结论 新型多聚体微泡携带舒尼替尼在超声作用下对人肾癌GRC-1细胞生长有明显抑制作用,并诱导细胞凋亡.     

Sensitization of ABCG2-overexpressing cells to conventional chemotherapeutic agent by sunitinib was associated with inhibiting the function of ABCG2

Sunitinib is an ATP-competitive multi-targeted tyrosine kinase inhibitor. In this study, we evaluated the possible interaction of sunitinib with P-glycoprotein (P-gp, ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), breast cancer resistance protein (BCRP, ABCG2) and lung-resistance protein (LRP) in vitro. Our results showed that sunitinib completely reverse drug resistance mediated by ABCG2 at a non-toxic concentration of 2.5 μM and has no significant reversal effect on ABCB1-, ABCC1- and LRP-mediated drug resistance, although a small synergetic effect was observed in combining sunitinib and conventional chemotherapeutic agents in ABCB1 overexpressing MCF-7/adr and parental sensitive MCF-7 cells, ABCC1 overexpressing C-A120 and parental sensitive KB-3-1 cells. Sunitinib significantly increased intracellular accumulation of rhodamine 123 and doxorubicin and remarkably inhibited the efflux of rhodamine 123 and methotrexate by ABCG2 in ABCG2-overexpressing cells, and also profoundly inhibited the transport of [³H]-methotrexate by ABCG2. However, sunitinib did not affect the expression of ABCG2 at mRNA or protein levels. In addition, sunitinib did not block the phosphorylation of Akt and Erk1/2 in ABCG2-overexpressing or parental sensitive cells. Overall, we conclude that sunitinib reverses ABCG2-mediated MDR through inhibiting the drug efflux function of ABCG2. These findings may be useful for cancer combinational therapy with sunitinib in the clinic.     

Response of imatinib-resistant extra-abdominal aggressive fibromatosis to sunitinib: case report and review of the literature on response to tyrosine kinase inhibitors

Purpose  Aggressive fibromatosis (AF) is usually a slowly growing locally invasive tumor, but may exhibit a much more aggressive phenotype. The role of chemotherapy in AF is not well defined, but can be useful in some cases. We examined the response of a case to both imatinib and sunitinib. Methods  We report a case of an aggressive multicentric extra-abdominal AF that was responsive to sunitinib, but resistant to imatinib. Results  A 23-year-old woman developed painful multifocal AF of both legs and gluteal muscles that progressed after surgery and treatment with methotrexate/vinblastine and pegylated-liposomal doxorubicin. She received six cycles of ifosfamide/etoposide (IMV), and obtained a good response with elimination of pain. After 5 months, she developed progression and again received six cycles of IMV, with cessation of symptoms. After 13 months, tumors recurred. Although the AF was symptomatic and progressing, she was hesitant to receive chemotherapy and began treatment with sunitinib 50 mg/day for 28 days of a 42-day cycle. At 4 months, she could walk on her heels without pain. After 13 months of sunitinib, therapy was changed to imatinib 400 mg/day; after 7 days she noticed increasing pain in the AF lesions and decreased knee flexibility. Imatinib was continued, but after 2 months of imatinib, she could only walk a few steps due to pain. Sunitinib was reinstituted at 37.5 mg/day and symptoms improved within 1.5 weeks, with a marked reduction of symptoms at 1 month. She was doing well with a normal activity level, 32 months after initially beginning sunitinib. Conclusions  We conclude that sunitinib may be useful in some cases of AF.     

Model-based assessment of pharmacokinetic changes of sunitinib,tacrolimus, and everolimus in a patient with metastatic renal cell carcinoma after renal transplantation

The safety of the coadministration of sunitinib with tacrolimus and everolimus with regard to therapeutic drug monitoring has not been demonstrated. Here, we report a patient who showed high sunitinib concentrations, in addition to pharmacokinetic changes in tacrolimus and everolimus after sunitinib therapy. A living-donor renal transplant patient treated with tacrolimus and everolimus was diagnosed with pulmonary and pleural metastases of renal cell carcinoma. The patient received sunitinib therapy (37.5 mg/day, 2 weeks on and 1 week off). This patient exhibited a high total sunitinib concentration (sunitinib, 105.8 ng/mL; N-desethyl sunitinib, 27.9 ng/mL) on day 10 postinitiation and experienced grade 3 diarrhea. The observed sunitinib concentrations were a little higher than those reported in the 421C>A polymorphism of the ATP-binding cassette subfamily G member 2 gene carrier. The observed concentrations of both tacrolimus and everolimus gradually decreased compared with the Bayesian-predicted values after the onset of sunitinib therapy, and the doses of tacrolimus and everolimus were increased. Careful therapeutic drug monitoring of sunitinib, tacrolimus, and everolimus concentrations is necessary during combination therapy, especially after episodes of diarrhea.     

Sunitinib Rechallenge in Patients With Metastatic Renal Cell Carcinoma

BackgroundSunitinib has been the standard of care for patients with metastatic renal cell carcinoma (mRCC). However, nearly all patients will eventually develop resistance. Before the introduction of novel agents, few treatment options remained after sunitinib failure. Sunitinib rechallenge is a strategy based on the presumption that resistance might be only temporary. The aim of this analysis was to evaluate the efficacy and safety of sunitinib rechallenge in patients with mRCC.Patients and MethodsPatients who had undergone sunitinib rechallenge (SU2) at the Medical University of Vienna from 2010 to 2017 were identified for the present retrospective study. The primary endpoint was the treatment duration with rechallenge (TD^SU2). The secondary endpoints included the treatment duration with upfront sunitinib (TD^SU1), progression-free survival (PFS^SU1 and PFS^SU2), overall survival (OS^SU1 and OS^SU2), the objective response rate in both settings (ORR^SU1 and ORR^SU2), and toxicity.ResultsA total of 31 patients were eligible. The median TD^SU2 was 7.2 months, and the median TD^SU1 was 17.8 months. The median OS^SU1 and OS^SU2 was 57.9 months and 14.7 months, respectively. The median PFS^SU1 and PFS^SU2 was 14.2 months and 5.6 months, respectively. The ORR^SU1 and ORR^SU2 was 34% and 16%, and another 48% and 42% achieved stable disease (SD), respectively. Fatigue and hypertension were the most common adverse events.ConclusionsSunitinib rechallenge appears to benefit patients in later treatment lines. With the abundance of novel treatment options available, this approach might appear less relevant. However, novel agents are not yet available everywhere. Thus, sunitinib rechallenge could be an additional strategy to improve the outcomes of patients with mRCC.