Short stature and dysmorphic features in Asian Indian siblings with DAAM2-associated steroid-resistant nephrotic syndrome: Expansion of the phenotypic spectrum or a blended phenotype?

Variants in more than 60 different genes, most of which code for podocyte-related proteins, have been found to be associated with monogenic forms of nephrotic syndrome (NS). Biallelic variants in DAAM2, a member of the formin family, were recently identified to cause autosomal recessive (AR) NS type 24 in four unrelated families with steroid-resistant nephrotic syndrome (SRNS). This case report represents only the fifth reported family of DAAM2-associated NS and the first from India, with two sibs who presented with a complex phenotype characterized by steroid-resistant nephrotic syndrome, short stature, dysmorphic facial features, deep-set toenails, myopia, increased thickness of the calvarium of the skull, and sloping ribs. Both sibs were found to have a homozygous likely pathogenic nonsense variant c.196C>T (p.Arg66Ter; NM_001201427.2) in exon 3 of the DAAM2 gene through whole exome sequencing. The dysmorphic features could possibly be part of the DAAM2-related phenotype which has hitherto not been reported or could represent a blended phenotype, with the extrarenal manifestations resulting from a yet to be identified coexisting genetic condition.

A novel guaiane sesquiterpene derivative, guai-2-en-10α-ol, from Ulva fasciata Delile inhibits EGFR/PI3K/Akt signaling and induces cytotoxicity in triple-negative breast cancer cells.

A novel guaiane sesquiterpene derivative, guai-2-en-10α-ol, from Ulva fasciata Delile exhibits antimicrobial property. U. fasciata extract was reported to exhibit cytotoxicity against cancer. In the present study, we have studied the anticancer potential of the compound, guai-2-en-10α-ol, from U. fasciata. The compound showed selective cytotoxicity toward triple-negative breast cancer (TNBC) cell line (MDA MB-231) in a dose-dependent manner. In treated cells, the apoptotic hallmarks such as formation of apoptotic bodies, cell shrinkage, and nuclear condensation were observed. Many small molecules affect the function of cellular signaling pathways. As EGFR/PI3K/Akt pathway proteins are frequently altered in TNBC, we have studied the gene expression of key proteins of this pathway. The semiquantitative PCR results demonstrated the down-regulated expression of PDPK1 (positive regulator) and Akt (key activator) as well as up-regulated expression of PTEN (negative regulator), which suggested the interaction of guai-2-en-10α-ol with upstream protein. Further investigation showed the down-regulation of both PI3K and EGFR. As EGFR is the most upstream protein of the pathway, its protein level expression was investigated. Western blotting analysis confirmed the down-regulation of p-EGFR expression and activation of apoptosis upon compound treatment. Cell cycle analysis also evidenced the G1 phase arrest, which can be due to the inhibition of cell survival pathway. Computational studies showed the interaction of guai-2-en-10α-ol with Asp855 residue of EGFR kinase domain in active conformation. All these results demonstrate the anticancer potential of guai-2-en-10α-ol through EGFR/PI3K/Akt pathway.

Identification of natural allosteric inhibitor for Akt1 protein through computational approaches and in vitro evaluation.

Akt, a serine/threonine protein kinase, is often hyper activated in breast and prostate cancers, but with poor prognosis. Allosteric inhibitors regulate aberrant kinase activity by stabilizing the protein in inactive conformation. Several natural compounds have been reported as inhibitors for kinases. In this study, to identify potential natural allosteric inhibitor for Akt1, we generated a seven-point pharmacophore model and screened it through natural compound library. Quercetin-7-O-ß-d-glucopyranoside or Q7G was found to be the best among selected molecules based on its hydrogen bond occupancy with key allosteric residues, persistent polar contacts and salt bridges that stabilize Akt1 in inactive conformation and minimum binding free energy during molecular dynamics simulation. Q7G induced dose-dependent inhibition of breast cancer cells (MDA MB-231) and arrested them in G1 and sub-G phase. This was associated with down-regulation of anti-apoptotic protein Bcl-2, up-regulation of cleaved caspase-3 and PARP. Expression of p-Akt (Ser473) was also down-regulated which might be due to Akt1 inhibition in inactive conformation. We further confirmed the Akt1 and Q7G interaction which was observed to have a dissociation constant (Kd) of 0.246µM. With these computational, biological and thermodynamic studies, we suggest Q7G as a lead molecule and propose for its further optimization.