Chemoproteomic Discovery of a Ritanserin-Targeted Kinase Network Mediating Apoptotic Cell Death of Lung Tumor Cells.

Ritanserin was tested in the clinic as a serotonin receptor inverse agonist but recently emerged as a novel kinase inhibitor with potential applications in cancer. Here, we discovered that ritanserin induced apoptotic cell death of non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) cells via a serotonin-independent mechanism. We used quantitative chemical proteomics to reveal a ritanserin-dependent kinase network that includes key mediators of lipid [diacylglycerol kinase α, phosphatidylinositol 4-kinase ß] and protein [feline encephalitis virus-related kinase, rapidly accelerated fibrosarcoma (RAF)] signaling, metabolism [eukaryotic elongation factor 2 kinase, eukaryotic translation initiation factor 2-α kinase 4], and DNA damage response [tousled-like kinase 2] to broadly kill lung tumor cell types. Whereas ritanserin exhibited polypharmacology in NSCLC proteomes, this compound showed unexpected specificity for c-RAF in the SCLC subtype, with negligible activity against other kinases mediating mitogen-activated protein kinase signaling. Here we show that ritanserin blocks c-RAF but not B-RAF activation of established oncogenic signaling pathways in live cells, providing evidence in support of c-RAF as a key target mediating its anticancer activity. Given the role of c-RAF activation in RAS-mutated cancers resistant to clinical B-RAF inhibitors, our findings may have implications in overcoming resistance mechanisms associated with c-RAF biology. The unique target landscape combined with acceptable safety profiles in humans provides new opportunities for repositioning ritanserin in cancer.

Ocular manifestations of Nabais Sa-de Vries Syndrome type 1.

Nabais Sa-de Vries syndrome (NSDVS) is a neurodevelopmental disorder first described in 2020. The syndrome is caused by de novo missense mutations in speckle-type pox virus and zinc finger protein (SPOP) on chromosome 17q21. The syndrome is divided into two forms (NSDVS Type 1 and NSDVS Type 2) based on the consequence of the mutation involved. In this report, we present the clinical features in a young male patient with suspected NSDVS1 and summarize the features of the reported affected individuals thus far, with a focus on the ophthalmic manifestations. Similar to other individuals with NSDVS1, he had features of congenital microcephaly, developmental delay, behavioral abnormalities, hearing loss, and facial dysmorphisms. Ocular and periorbital manifestations in this patient included thick high-arched eyebrows, mild synophrys, long eyelashes, ptosis, and downslanting palpebral fissures; comparable to features described in other individuals with NSDVS1. In addition, this patient had esotropia that required multiple strabismus surgeries and a refractive error that required the use of corrective lenses. Although the consequences of specific mutations may result in a portion of the phenotypic differences between NSDVS1 and NSDVS2, the ophthalmic abnormalities between the two types may have significant overlap not explained by these bidirectional mutational effects.