Thrombospondin-1 counteracts the p97 inhibitor CB-5083 in colon carcinoma cells

Discovery and Development of a Selective Inhibitor of the ER Resident Chaperone Grp78

A recent study illustrated that a fluorescence polarization assay can be used to identify substrate-competitive Hsp70 inhibitors that can be isoform-selective. Herein, we use that assay in a moderate-throughput screen and report the discovery of a druglike amino-acid-based inhibitor with reasonable specificity for the endoplasmic reticular Hsp70, Grp78. Using traditional medicinal chemistry approaches, the potency and selectivity were further optimized through structure-activity relationship (SAR) studies in parallel assays for six of the human Hsp70 isoforms. The top compounds were all tested against a panel of cancer cell lines and disappointingly showed little effect. The top-performing compound, 8, was retested using a series of endoplasmic reticulum (ER) stress-inducing agents and found to synergize with these agents. Finally, 8 was tested in a spheroid tumor model and found to be more potent than in two-dimensional models. The optimized Grp78 inhibitors are the first reported isoform-selective small-molecule-competitive inhibitors of an Hsp70-substrate interaction.

A Comparative Analysis of Mucus Immunomodulatory Properties from Seven Marine Gastropods from the Mediterranean Sea

The treatment of inflammatory and immune-related diseases due to dysfunctioning of the immune system necessitates modulation of the immune response through immunomodulatory compounds. Marine environments are considered as a new frontier for health benefit product implementations. Marine biodiversity is still a low explored resource, despite it is expected to represent an important platform for chemical bioactive compounds. Within the phylum Mollusca, gastropods are known to synthetize mucus, the latter presenting relevant bioactive properties, e.g., related to immunomodulant molecules able to activate the innate and acquired immune system. This study proposes a bioprospecting of the immunomodulant activity of mucus isolated from seven common gastropod species from the Gulf of Naples (Mediterranean Sea). Results showed that not all mucus displayed a significant cytotoxic activity on the two human cancer cell lines A549 and A2058. On the other hand, the mucus from Bolinus brandaris was strongly bioactive and was therefore thoroughly investigated at cellular, molecular, and protein levels on the human monocytes U937 line. It can conclusively induce monocyte differentiation in vitro and significantly stimulate natural immunity response.

The multifaceted role of Matricellular Proteins in health and cancer, as biomarkers and therapeutic targets

The extracellular matrix (ECM) is composed of a mesh of proteins, proteoglycans, growth factors, and other secretory components. It constitutes the tumor microenvironment along with the endothelial cells, cancer-associated fibroblasts, adipocytes, and immune cells. The proteins of ECM can be functionally classified as adhesive proteins and matricellular proteins (MCP). In the tumor milieu, the ECM plays a major role in tumorigenesis and therapeutic resistance. The current review encompasses thrombospondins, osteonectin, osteopontin, tenascin C, periostin, the CCN family, laminin, biglycan, decorin, mimecan, and galectins. The matrix metalloproteinases (MMPs) are also discussed as they are an integral part of the ECM with versatile functions in the tumor stroma. In this review, the role of these proteins in tumor initiation, growth, invasion and metastasis have been highlighted, with emphasis on their contribution to tumor therapeutic resistance. Further, their potential as biomarkers and therapeutic targets based on existing evidence are discussed. Owing to the recent advancements in protein targeting, the possibility of agents to modulate MCPs in cancer as therapeutic options are discussed.

Valosin-Containing Protein (VCP)/p97: A Prognostic Biomarker and Therapeutic Target in Cancer

Valosin-containing protein (VCP)/p97, a member of the AAA+ ATPase family, is a molecular chaperone recruited to the endoplasmic reticulum (ER) membrane by binding to membrane adapters (nuclear protein localization protein 4 (NPL4), p47 and ubiquitin regulatory X (UBX) domain-containing protein 1 (UBXD1)), where it is involved in ER-associated protein degradation (ERAD). However, VCP/p97 interacts with many cofactors to participate in different cellular processes that are critical for cancer cell survival and aggressiveness. Indeed, VCP/p97 is reported to be overexpressed in many cancer types and is considered a potential cancer biomarker and therapeutic target. This review summarizes the role of VCP/p97 in different cancers and the advances in the discovery of small-molecule inhibitors with therapeutic potential, focusing on the challenges associated with cancer-related VCP mutations in the mechanisms of resistance to inhibitors.

Down-regulating circular RNA_0004674 delays the progression of oral squamous cell carcinoma through microRNA-377-3p/THBS1 axis

OBJECTIVE

Circular RNAs (CircRNAs) are of great significance in oral squamous cell carcinoma (OSCC) cell progression. Insufficiently, the performance of Circ_0004674 has not been specified in the disease, which alighted our desire to unmask its actions in OSCC cell progression with microRNA (miR)-377-3p and thrombospondin-1 (THBS1).

METHODS

OSCC expression chip were collected through GEO database and analyzed. The upstream mechanism of THBS1 was predicted through databases. OSCC cancer tissues and normal tissues were resected, in which Circ_0004674, miR-377-3p and THBS1 expression were examined. The relationship of Circ_0004674, miR-377-3p and THBS1 was identified. Circ_0004674- and/or miR-377-3p-related oligonucleotides were transfected into CAL27 cells for detecting cell biological behaviors. Tumors in mice were implanted to monitor the tumor-forming ability of cells.

RESULTS

THBS1 showed high expression in the three OSCC chips, and it was enriched in PI3K-AKT signaling pathway. The upstream mechanism of THBS1 predicted that Circ_0004674 regulated THBS1 through miR-377-3p. Circ_0004674 and THBS1 levels were enhanced while miR-377-3p level was reduced in OSCC. Down-regulating Circ_0004674 restricted the growth of CAL27 cells in vivo and in vitro. Restoring miR-377-3p, the target gene of Circ_0004674, destroyed CAL27 cell progression and tumor growth. miR-377-3p suppression rescued the effects of down-regulated Circ_0004674 on OSCC. THBS1 was negatively mediated by miR-377-3p.

CONCLUSION

It is clarified that depleting Circ_0004674 mediates miR-377-3p to restrain THBS1, after which OSCC cell progression can be suppressed. It widens the way to control OSCC from a novel perspective.