Evaluation of a self-questionnaire to screen for neurological complications associated with immunological checkpoint inhibitors: Are we missing something?

INTRODUCTION: Immunological checkpoint inhibitors (ICI) have led to a therapeutic revolution in the management of many cancers and indications are increasing. Neurological complications seem to have a profile quite distinct from that of toxicities related to chemotherapy, although it is possible that some manifestations remain under-reported or misdiagnosed. OBJECTIVES: (i) To evaluate the value of a self-questionnaire in screening for neurological ICI-related complications. (ii) To investigate whether, apart from the subacute complications described in the literature, neurological complications of more insidious onset might occur. METHOD: Patients followed in dermatology department for skin cancers treated with ICI, completed every infusion a neurological screening auto-questionnaire. Patients were selected for a neurological expertise based on the questionnaire's data. RESULTS: In total, 149 patients completed≥1 questionnaire, with a median delay of 174 days from the start of treatment. A total of 229 questionnaires were completed between July 2019 and December 2019. 38 patients were identified for a neurological consultation. None of these patients had a neurological event attributable to ICI. During the follow-up, only one patient had a neurological event related to ICI, which was not revealed by the questionnaire. DISCUSSION: Neurological signs in ICI-treated-skin-cancer context are more often due to tumoral progression. Neurological complications of ICI remain rare and unpredictable. The systematic neurological questionnaire has not been shown to be useful in this context. These results highlight the need to educate patients about possible subacute signs that should lead to contact the treating physicians and the need for a close cooperation between dermatologists/oncologists and neurologists.

Inactivation of the glial fibrillary acidic protein gene, but not that of vimentin, improves neuronal survival and neurite growth by modifying adhesion molecule expression.

Intermediate filaments (IFs) are a major component of the cytoskeleton in astrocytes. Their role is far from being completely understood. Immature astrocytes play a major role in neuronal migration and neuritogenesis, and their IFs are mainly composed of vimentin. In mature differentiated astrocytes, vimentin is replaced by the IF protein glial fibrillary acidic protein (GFAP). In response to injury of the CNS in the adult, astrocytes become reactive, upregulate the expression of GFAP, and reexpress vimentin. These modifications contribute to the formation of a glial scar that is obstructive to axonal regeneration. Nevertheless, astrocytes in vitro are considered to be the ideal substratum for the growth of embryonic CNS axons. In the present study, we have examined the potential role of these two major IF proteins in both neuronal survival and neurite growth. For this purpose, we cocultured wild-type neurons on astrocytes from three types of knock-out (KO) mice for GFAP or/and vimentin in a neuron-astrocyte coculture model. We show that the double KO astrocytes present many features of immaturity and greatly improve survival and neurite growth of cocultured neurons by increasing cell-cell contact and secreting diffusible factors. Moreover, our data suggest that the absence of vimentin is not a key element in the permissivity of the mutant astrocytes. Finally, we show that only the absence of GFAP is associated with an increased expression of some extracellular matrix and adhesion molecules. To conclude, our results suggest that GFAP expression is able to modulate key biochemical properties of astrocytes that are implicated in their permissivity.

Identification of potent non-peptide somatostatin antagonists with sst(3) selectivity.

Using a solution-phase parallel synthesis strategy, a series of non-peptide somatostatin analogues were prepared, and their binding affinities to the five human somatostatin receptor subtypes (sst(1-5)) were determined. Imidazolyl derivatives 2 were found to bind with moderate affinity but with high selectivity to the sst(3) receptor subtype. Further modifications of these structures led to a more potent class of ligands, the tetrahydro-beta-carboline derivatives 4. Among these, compounds 4k (BN81644) and 4n (BN81674) bind selectively and with high affinity to the sst(3) receptor subtype (K(i) = 0.64 and 0.92 nM, respectively). Furthermore, 4k and 4n reverse the inhibition of cyclic AMP accumulation induced by 1 nM somatostatin via sst(3) receptors, with IC(50) = 2.7 and 0.84 nM, respectively. The most potent compound 4n was shown to be a competitive antagonist of human sst(3) receptors by increasing the EC(50) of SRIF-14-mediated inhibition of cAMP accumulation with a K(B) of 2.8 nM (where K(B) is the concentration of antagonist that shifts the agonist dose-response 2-fold). These new derivatives are, to our knowledge, the first potent and highly selective non-peptide human sst(3) antagonists known and, as such, are useful tools for investigating the physiological role of sst(3) receptors.