In vivo studies of a peptidomimetic that targets EGFR dimerization in NSCLC

Biochemical Pathways Delivering Distinct Glycosphingolipid Patterns in MDA-MB-231 and MCF-7 Breast Cancer Cells

The complex structure of glycosphingolipids (GSLs) supports their important role in cell function as modulators of growth factor receptors and glutamine transporters in plasma membranes. The aberrant composition of clustered GSLs within signaling platforms, so-called lipid rafts, inevitably leads to tumorigenesis due to disturbed growth factor signal transduction and excessive uptake of glutamine and other molecules needed for increased energy and structural molecule cell supply. GSLs are also involved in plasma membrane processes such as cell adhesion, and their transition converts cells from epithelial to mesenchymal with features required for cell migration and metastasis. Glutamine activates the mechanistic target of rapamycin complex 1 (mTORC1), resulting in nucleotide synthesis and proliferation. In addition, glutamine contributes to the cancer stem cell GD2 ganglioside-positive phenotype in the triple-negative breast cancer cell line MDA-MB-231. Thieno[2,3-b]pyridine derivative possesses higher cytotoxicity against MDA-MB-231 than against MCF-7 cells and induces a shift to aerobic metabolism and a decrease in S(6)nLc4Cer GSL-positive cancer stem cells in the MDA-MB-231 cell line. In this review, we discuss findings in MDA-MB-231, MCF-7, and other breast cancer cell lines concerning their differences in growth factor receptors and recent knowledge of the main biochemical pathways delivering distinct glycosphingolipid patterns during tumorigenesis and therapy.

Peptides and peptidomimetics as therapeutic agents for Covid-19

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Covid-19 pandemic has caused high morbidity and mortality rates worldwide. Virus entry into cells can be blocked using several strategies, including inhibition of protein-protein interactions (PPIs) between the viral spike glycoprotein and cellular receptors, as well as blocking of spike protein conformational changes that are required for cleavage/activation and fusogenicity. The spike-mediated viral attachment and entry into cells via fusion of the viral envelope with cellular membranes involve PPIs mediated by short peptide fragments exhibiting particular secondary structures. Thus, peptides that can inhibit these PPIs may be used as potential antiviral agents preventing virus entry and spread. This review is focused on peptides and peptidomimetics as PPI modulators and protease inhibitors against SARS-CoV-2.

A grafted peptidomimetic for EGFR heterodimerization inhibition: Implications in NSCLC models

Among the lung cancers, approximately 85% are histologically classified as non-small-cell lung cancer (NSCLC), a leading cause of cancer deaths worldwide. Epidermal growth factor receptors (EGFRs) are known to play a crucial role in lung cancer. HER2 overexpression is detected by immunohistochemistry in 2.4%-38% of NSCLC samples. EGFRs have been targeted with three generations of tyrosine kinase inhibitors (TKIs), and drug resistance has become a major issue; HER2 dimerization with EGFR also plays a major role in the development of resistance to TKI therapy. We have designed grafted peptides to bind to the HER2 extracellular domain (ECD) and inhibit protein-protein interactions of EGFR:HER2 and HER2:HER3. A sunflower trypsin inhibitor (SFTI-1) template was used to graft a peptidomimetic compound. Among several grafted peptides, SFTI-G5 exhibited antiproliferative activity in HER2-positive NSCLC cell lines such as Calu-3 cells with an IC50 value of 0.073 μM. SFTI-G5 was shown to bind to ECD of HER2 and inhibit EGFR:HER2 and HER2:HER3 dimerization and inhibit the phosphorylation of HER2 and downstream signaling proteins. As a proof-of-concept, the in vivo activity of SFTI-G5 was evaluated in two NSCLC mouse models. SFTI-G5 was able to inhibit tumor growth in both models. Furthermore, SFTI-G5 was shown to inhibit EGFR dimerization in tissue samples obtained from in vivo models. These grafted peptides can be used as novel dual inhibitors of EGFR dimerization in NSCLC.

Mechanisms and Future of Non-Small Cell Lung Cancer Metastasis

Lung cancer, renowned for its fast progression and metastatic potency, is rising to become a leading cause of death globally. It has been long observed that lung cancer is particularly ept in spawning distant metastasis at its early stages, and it can readily colonize virtually any human organ. In recent years, cancer research has shed light on why lung cancer is endowed with its exceptional ability to metastasize. In this review, we will take a comprehensive look at the current research on lung cancer metastasis, including molecular pathways, anatomical features and genetic traits that make lung cancer intrinsically metastatic, as we go from lung cancer’s general metastatic potential to the particular metastasis mechanisms in multiple organs. We highly concerned about the advanced discovery and development of lung cancer metastasis, indicating the importance of lung cancer specific gene mutations, heterogeneity or biomarker discovery, and discussing potential opportunities and challenges. We will also introduce some current treatments that targets certain metastatic strategies of non-small cell lung cancer (NSCLC). Advances made in these regards could be critical to our current knowledge base of lung cancer metastasis.