A novel ex vivo high-throughput assay reveals antiproliferative effects of idelalisib and ibrutinib in chronic lymphocytic leukemia

PI3Kδ (idelalisib) and BTK (ibrutinib) inhibitors have demonstrated significant clinical activity in chronic lymphocytic leukemia (CLL) interfering with the cross-talk between CLL cells and the lymph node microenviroment, yet their mechanism of action remains to be fully elucidated. Here, we developed an ex vivo model with the aim of reproducing the effects of the microenvironment that would help shed light on the in vivo mechanism of action of idelalisib and ibrutinib and predict their clinical efficacy in individual patients. First we explored the effects of various cell-extrinsic elements on CLL apoptosis and proliferation and found that the combination of CpG+IL2+HS5 stromal cell line + human serum +CLL plasma and erythrocyte fractions represented the best co-culture conditions to test the effects of the novel inhibitors. Then, using this assay, we investigated the impact of idelalisib and ibrutinib on both survival and proliferation in 30 CLL patients. While both drugs had a limited direct pro-apoptotic activity, a potent inhibition of proliferation was achieved at clinically achievable concentrations. Notably, up to 10% of CLL cells still proliferated even at the highest concentrations, likely mirroring the known difficulty to achieve complete responses in vivo. Altogether, this novel assay represents an appropriate ex vivo drug testing system to potentially predict the clinical response to novel inhibitors in particular by quantifying the antiproliferative effect.

Increasing TIMP3 expression by hypomethylating agents diminishes soluble MICA, MICB and ULBP2 shedding in acute myeloid leukemia, facilitating NK cell-mediated immune recognition

Acute myeloid leukemia (AML) is a disease with great morphological and genetic heterogeneity, which complicates its prognosis and treatment. The hypomethylating agents azacitidine (Vidaza®, AZA) and decitabine (Dacogen®, DAC) have been approved for the treatment of AML patients, but their mechanisms of action are poorly understood. Natural killer (NK) cells play an important role in the recognition of AML blasts through the interaction of the activating NKG2D receptor with its ligands (NKG2DL: MICA/B and ULBPs1-3). However, soluble NKG2DL (sNKG2DL) can be released from the cell surface, impairing immune recognition. Here, we examined whether hypomethylating agents modulate the release of sNKG2DL from AML cells. Results demonstrated that AZA- and DAC-treated AML cells reduce the release of sNKG2DL, preventing downregulation of NKG2D receptor on the cell surface and promoting immune recognition mediated by NKG2D-NKG2DL engagement. We show that the shedding of MICA, MICB and ULBP2 is inhibited by the increased expression of TIMP3, an ADAM17 inhibitor, after DAC treatment. The TIMP3 gene is highly methylated in AML cells lines and in AML patients (25.5%), in which it is significantly associated with an adverse cytogenetic prognosis of the disease. Overall, TIMP3 could be a target of the demethylating treatments in AML patients, leading to a decrease in MICA, MICB and ULBP2 shedding and the enhancement of the lytic activity of NK cells through the immune recognition mediated by the NKG2D receptor.

[Atherothrombotic carotid disease: towards a consensus on its prevention]

This consensus document was one of the objectives of the I Meeting of the Spanish Society of Angiology and Vascular Surgery, the Spanish Interventional Neuroradiology Group of the Spanish Society of Neuroradiology, and the Cerebrovascular Disease Study Group of the Spanish Society of Neurology, which was held in October 2002 in Cordoba. Atherosclerosis is a chronic vascular disease of true epidemic proportions. It is the first cause of death in developed countries and responsible for one quarter of documented deaths worldwide. Atherothrombotic ischemic stroke, transient ischemic attack and atherothrombotic origin symptomatic or asymptomatic peripheral arterial disease are all associated with a high risk of vascular death, myocardial infarction and recurrent stroke. In this context, vascular disease represents a serious public health problem, particularly if we take into account current forecasts on population ageing. The prevention of atherosclerosis - and its consequences, if its clinical manifestations are already apparent - is therefore a priority. This multidisciplinary consensus document draws on the different medical specialties dealing with these patients and combines efforts to obtain the greatest possible benefit as regards this disease's management. The consensus document makes a global analysis of atherosclerosis prevention, basically in terms of therapeutic objectives, lifestyle change measures, high bloodpressure management, dyslipidemia, other vascular risk factors and platelet antiaggregation. Emphasis is placed on the frequent coexistence of cerebrovascular and peripheral arterial involvement, and the methods of detecting silent involvement. Lastly, consensus is reached on the diagnostic methods and specific management of atherothrombotic carotid disease, including the benefits and risks of and indications for carotid endarterectomy, and the current role of carotid angioplasty.

[Intra-arterial chemotherapy, using the hepatic artery, in metastases of colorectal carcinoma]

Hepatic metastasis is the major cause of death in advanced cancer of the colon and rectum. Various modes of therapy have been attempted with only partial success. Infusion of cytotoxic agents into the hepatic artery has allowed a higher concentration of drug into the tumor capillary bed than is achievable with intravenous administration. We review the data on therapeutic outcome, administration techniques and toxicity of hepatic arterial chemotherapy for colorectal cancer metastatic to the liver.