Discovery of 4-anilino α-carbolines as novel Brk inhibitors.

Dysregulation of cell signalling processes caused by an enhanced activity of protein kinases mainly contributes to cancer progression. Protein kinase inhibitors have been established as promising drugs that inhibit such overactive protein kinases in cancer cells. The formation of metastases, which makes a therapy difficult, remains a great challenge for cancer treatment. Recently, breast tumor kinase (Brk) was discovered as novel and interesting target for a cancer therapy because Brk participates in both cell dysregulation and metastasis. We discovered 4-anilino substituted α-carboline compounds as a novel class of highly active Brk inhibitors. In the current work, structure-activity relationships are discussed including docking results obtained for 4-anilino α-carbolines. A first profiling of selective kinase inhibition and a proof of concept for the antiproliferative effects is demonstrated. These results qualify the compounds as a promising class of novel antitumor agents.

Development of small-molecule P-gp inhibitors of the N-benzyl 1,4-dihydropyridine type: novel aspects in SAR and bioanalytical evaluation of multidrug resistance (MDR) reversal properties.

Novel series of N-benzyl 1,4-dihydropyridines have been prepared by facile syntheses. All relevant substituents of the molecular scaffold have been varied. The resulting compounds were biologically evaluated as P-glycoprotein (P-gp) inhibitors. Substitutions of the N-benzyl residue favour biological activity beside respective 3-ester functions. Most active compounds were further evaluated as multidrug resistance (MDR) modulators to restore the cytotoxic properties of varying daunorubicin applications.

Melanoma-Derived Exosomal miR-125b-5p Educates Tumor Associated Macrophages (TAMs) by Targeting Lysosomal Acid Lipase A (LIPA).

Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment, promoting tumor initiation, growth, progression, metastasis, and immune evasion. Recently it was shown that cancer cell-derived exosomes induce a tumor-promoting phenotype in TAMs. Exosome-loaded proteins, DNA, and RNAs may contribute to the macrophage reprogramming. However, the exact mediators and mechanisms, particularly in melanoma, are not known. In this study we examined the effects of cutaneous melanoma-derived exosomes on macrophage function and the underlying mechanisms. First, we showed that exposure to melanoma exosomes induces a tumor-promoting TAM phenotype in macrophages. Sequencing revealed enrichment for several miRNAs including miR-125b-5p in cutaneous melanoma exosomes. We showed that miR-125b-5p is delivered to macrophages by melanoma exosomes and partially induces the observed tumor-promoting TAM phenotype. Finally, we showed that miR-125b-5p targets the lysosomal acid lipase A (LIPA) in macrophages, which in turn contributes to their phenotype switch and promotes macrophage survival. Thus, our data show for the first time that miR-125b-5p transferred by cutaneous melanoma-derived exosomes induces a tumor-promoting TAM phenotype in macrophages.