CD44 Is Involved in Tumor Angiogenesis; an Activation Antigen on Human Endothelial Cells

Hyaluronan network: a driving force in cancer progression

Hyaluronan is one of the most abundant macromolecules of the extracellular matrix and regulates several physiological cell and tissue properties. However, hyaluronan has been shown to accumulate together with its receptors in various cancers. In tumors, accumulation of hyaluronan system components (hyaluronan synthesizing/degrading enzymes and interacting proteins) associates with poor outcomes of the patients. In this article, we review the main roles of hyaluronan in normal physiology and cancer, and further discuss the targeting of hyaluronan system as an applicable therapeutic strategy.

Genome-wide expression of the residual lung reacting to experimental Pneumonectomy

Background

Acute or chronic irreversible respiratory failure may occur in patients undergoing pneumonectomy. Aim of this study was to determine transcriptome expression changes after experimental pneumonectomy in swine model. Experimental left pneumonectomy was performed in five pigs under general anaesthesia. Both the resected and the remaining lung, after 60 post-operative completely uneventful days, underwent genome-wide bulk RNA-Sequencing (RNA-Seq).

Results

Histological analysis showed dilation of air spaces and rupture of interalveolar septa. In addition, mild inflammation, no fibrosis, radial stretch of the bronchus, strong enlargement of airspaces and thinning of the blood supply were observed. Bioinformatic analyses of bulk RNA-Seq data identified 553 Differentially Expressed Genes (DEGs) at adjusted P-value below 0.001, between pre- and post-pneumonectomy. The top 10 up-regulated DEGs were Edn1, Areg, Havcr2, Gadd45g, Depp1, Cldn4, Atf3, Myc, Gadd45b, Socs3; the top 10 down-regulated DEGs were Obscn, Cdkn2b, ENSSSCG00000015738, Prrt2, Amer1, Flrt3, Efnb2, Tox3, Znf793, Znf365. Leveraging digital cytometry tools, no difference in cellular abundance was found between the two experimental groups, while the analysis of cell type-specific gene expression patterns highlighted a striking predominance of macrophage-specific genes among the DEGs. DAVID-based gene ontology analysis showed a significant enrichment of “Extrinsic apoptotic signaling pathway” (FDR q = 7.60 × 10^− 3) and “Response to insulin” (FDR q = 7.60 × 10^− 3) genes, along with an enrichment of genes involved as “Negative regulators of DDX58/IFIH1 signaling” (FDR q = 7.50 × 10^− 4) found by querying the REACTOME pathway database. Gene network analyses indicated a general dysregulation of gene inter-connections.

Conclusion

This translational genomics study highlighted the existence both of individual genes, mostly dysregulated in certain cellular populations (e.g., macrophages), and gene-networks involved in pulmonary reaction after left pneumonectomy. Their involvement in lung homeostasis is largely supported by previous studies, carried out both in humans and in other animal models (under homeostatic or disease-related conditions), that adopted candidate-gene approaches. Overall, the present findings represent a preliminary assessment for future, more focused, studies on compensatory lung adaptation, pulmonary regeneration and functional reload.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08171-3.

CD44 in Ovarian Cancer Progression and Therapy Resistance-A Critical Role for STAT3

Despite significant progress in cancer therapy over the last decades, ovarian cancer remains the most lethal gynecologic malignancy worldwide with the five-year overall survival rate less than 30% due to frequent disease recurrence and chemoresistance. CD44 is a non-kinase transmembrane receptor that has been linked to cancer metastatic progression, cancer stem cell maintenance, and chemoresistance development via multiple mechanisms across many cancers, including ovarian, and represents a promising therapeutic target for ovarian cancer treatment. Moreover, CD44-mediated signaling interacts with other well-known pro-tumorigenic pathways and oncogenes during cancer development, such as signal transducer and activator of transcription 3 (STAT3). Given that both CD44 and STAT3 are strongly implicated in the metastatic progression and chemoresistance of ovarian tumors, this review summarizes currently available evidence about functional crosstalk between CD44 and STAT3 in human malignancies with an emphasis on ovarian cancer. In addition to the role of tumor cell-intrinsic CD44 and STAT3 interaction in driving cancer progression and metastasis, we discuss how CD44 and STAT3 support the pro-tumorigenic tumor microenvironment and promote tumor angiogenesis, immunosuppression, and cancer metabolic reprogramming in favor of cancer progression. Finally, we review the current state of therapeutic CD44 targeting and propose superior treatment possibilities for ovarian cancer.

Recombinant CD44-HABD is a novel and potent direct angiogenesis inhibitor enforcing endothelial cell-specific growth inhibition independently of hyaluronic acid binding

CD44 is the main cellular receptor for hyaluronic acid (HA). We previously found that overexpression of CD44 inhibited tumor growth of mouse fibrosarcoma cells in mice. Here, we show that soluble recombinant CD44 HA-binding domain (CD44-HABD) acts directly onto endothelial cells by inhibiting endothelial cell proliferation in a cell-specific manner. Consequently, soluble recombinant CD44-HABD also blocked angiogenesis in vivo in chick and mouse, and thereby inhibited tumor growth of various origins at very low doses (0.25 mg/kg x day). The antiangiogenic effect of CD44 is independent of its HA-binding capacity, since mutants deficient in HA binding still maintain their antiangiogenic and antiproliferative properties. Recombinant CD44-HABD represents a novel class of angiogenesis inhibitors based on a cell-surface receptor.

Identification of an active site on the laminin alpha5 chain globular domain that binds to CD44 and inhibits malignancy

The laminin alpha5 chain is a component of laminin-10 (alpha5beta1gamma1) and -11 (alpha5beta2gamma1). In this study, we have screened 113 overlapping synthetic peptides from the laminin alpha5 globular domain (G-domain) for cell attachment activity with B16-F10 cells using peptide-coated dishes. Eleven attachment-active peptides were identified. In vivo experimental B16-F10 pulmonary metastasis and primary tumor growth assays found that 4 of the 11 peptides inhibited tumor metastasis and growth and increased apoptosis. These four peptides also blocked tumor cell migration, invasion, and angiogenesis. Two of the peptides were highly homologous and showed significant similarity to sequences in collagens. We sought to identify the B16-F10 cell surface receptors for each of the four active peptides using peptide affinity chromatography. Only one peptide recognized a cell surface protein. Peptide A5G27 (RLVSYNGIIFFLK, residues 2892-2904) bound a diffuse M(r) approximately 120,000-180,000 band that eluted with 2 m NaCl. Glycosidase digestion of the 2 m eluate yielded protein bands of M(r) 90,000 and 60,000 that reacted in Western blot analysis with antibodies to CD44. Immunoprecipitation of the A5G27-bound membrane proteins with various cell surface proteoglycan antibodies confirmed CD44 as the surface receptor for A5G27. Finally, attachment assays to A5G27 in the presence of soluble glycosaminoglycans (GAGs) identified the GAGs of CD44 as the binding sites for A5G27. Our results suggest that A5G27 binds to the CD44 receptor of B16-F10 melanoma cells via the GAGs on CD44 and, thus, inhibits tumor cell migration, invasion, and angiogenesis in a dominant-negative manner.

Redirected infection of directly biotinylated recombinant adenovirus vectors through cell surface receptors and antigens

The inability of adenovirus to infect primitive hematopoietic cells presents an obstacle to the use of adenovirus vectors for gene transfer to these cell types. Therefore, expanding the tropism of adenovirus vectors to unique cell surface antigens would be an important development for gene therapy protocols. In this study, we sought to redirect infection of adenovirus vectors to primitive human hematopoietic cells that universally express the c-Kit receptor on their cell surface. To accomplish this, a vector was constructed by covalently linking biotin molecules to recombinant adenovirus, followed by addition of the biotinylated ligand for the c-Kit receptor, stem cell factor (SCF), through an avidin bridge. Gene transfer was directed specifically to c-Kit-positive hematopoietic cell lines, resulting in up to a 2,440-fold increase in luciferase expression with frequencies equivalent to recombinant virus infection of permissive cells. Substitution of biotinylated antibodies directed against c-Kit, CD34 (binds L-selectin), and CD44 (hyaluronate receptor) receptors for biotinylated SCF resulted in 50-, 8-, and 260-fold increases in reporter gene expression, respectively, demonstrating that infection also could be redirected through antibody-antigen interactions and through antigens other than growth factor receptors. The versatility of this vector was demonstrated further by infection of primary T cells with vectors targeted with antibodies to CD44 (resting and activated T cells) and biotinylated IL-2 (activated T cells only). Taken together, directly biotinylated adenovirus vectors represent a versatile and efficient method for redirection of virus infection to specific cells.