Asiatic acid as a leading structure for derivatives combining sub-nanomolar cytotoxicity, high selectivity, and the ability to overcome drug resistance in human preclinical tumor models

Combination of Betulinic Acid Fragments and Carbonic Anhydrase Inhibitors—A New Drug Targeting Approach

“…Tumor spheroids are useful in vitro models representing several important aspects of real tumor tissues, i.e., three-dimensional growth with structural organization and physiologically relevant cell–cell and cell–matrix interactions; establishment of tumor microenvironmental characteristics, such as nutrient gradients, hypoxia and acidosis; as well as elucidation of drug resistance mechanisms [ 33 , 34 ]. For this purpose, we used our model comprising two breast cancer cell line derived spheroid types, MDA-MB-231 and Hs578T, with the latter one showing 60-fold and 20-fold resistance to the clinically relevant drugs doxorubicin and paclitaxel, respectively [ 29 ]. Since the tumor cells stably express luciferase, analysis of spheroid growth and response to therapy is accomplished by measurement of bioluminescent signal intensity.…”

“…To determine cytotoxicity in the 3D tumor models, spheroid cytotoxicity assays were performed as previously described [ 29 ]. The luciferase-expressing, breast cancer cell lines MDA-MB-231 and Hs578T and derived spheroids were cultivated in RPMI medium (Sigma-Aldrich, Taufkirchen, Germany) containing 10% fetal bovine serum (BioWest, Nuaillé, France) and 10% penicillin/streptomycin (Sigma-Aldrich) at 37 °C/5% CO 2 in a humid atmosphere.…”

Mitochondria-Targeting 1,5-Diazacyclooctane-Spacered Triterpene Rhodamine Conjugates Exhibit Cytotoxicity at Sub-Nanomolar Concentration against Breast Cancer Cells

“…The starting materials for the preparation of the spacered rhodamine conjugates were the triterpene carboxylic acids oleanolic acid (OA, Figure 1), ursolic acid (UA), and the lupanes betulinic acid (BA) and platanic acid (PA); in previous works, asiatic acid (AA) had been shown to be particularly suitable with respect to cytotoxic activity and was, therefore, included in this study as a model featuring a tri-hydroxylated triterpene carboxylic acid [21]. The starting materials for the preparation of the spacered rhodamine conjugates were the triterpene carboxylic acids oleanolic acid (OA, Figure 1), ursolic acid (UA), and the lupanes betulinic acid (BA) and platanic acid (PA); in previous works, asiatic acid (AA) had been shown to be particularly suitable with respect to cytotoxic activity and was, therefore, included in this study as a model featuring a tri-hydroxylated triterpene carboxylic acid [21]. The triterpenoic acids were acetylated to yield the acetates 9-13 (Scheme 2).…”

“…(3ß)-3-Acetyloxy-28-(5-{2-[3,6-bis(diethylamino)xanthen-10-ium-9-yl]benzoyl}-1,5diazocan-1-yl)-28-oxolup-20(29)-ene Chloride(21) Following GP 3 from 16 (300 mg, 0.5 mmol) and rhodamine B (200 mg, 0.4 mmol), followed by chromatography (silica gel, CHCl 3 /MeOH, 9:1), 21 (3536 mg, 69%) was obtained as a pink solid; m.p. = 212-218 • C; R f = 0.49 (CHCl 3 /MeOH, 9:1); UV-Vis (CHCl 3 ): λ max (log ε) = 562 nm (4.43); IR (ATR): ν = 2936w, 1730w, 1587s, 1465m, 1411s, 1335s, 1244s, 1179s, 1132m, 1073m, 978w, 921w, 684m cm−1 ; 1 H NMR (400 MHz, CDCl 3 ): δ = 7.52-7.47 (m, 2H, 43-H, 44-H), 7.43-7.37 (m, 1H, 42-H), 7.22-6.99 (m, 3H, 45-H, 48-H), 6.97-6.71 (m, 2H, 49-H), 6.64-6.57 (m, 2H, 51-H), 4.58-4.50 (m, 1H, 29-H a ), 4.42-4.37 (m, 1H, 29-H b ), 4.30 (m, 1H, 3-H), 3.73-2.93 (m, 16H, 33-H, 35-H, 36-H, 38-H, 53-H), 2.83-2.68 (m, 2H, 19-H, 13-H), 2.00-1.94 (m, 1H, 16-H a ), 1.87 (s, 3H, 32-H), 1.83-1.54 (m, 4H, 22-H a , 15-H, 21-H a ), 1.53-1.51 (m, 2H, 12-H a , 1-H a ), 1.50 (s, 3H, 30-H), 1.47-1.42 (m, 2H, 2-H), 1.41-1.36 (m, 1H, 18-H), 1.35-1.29 (m, (C-6), 16.4 (C-26), 15.9 (C-25), 14.7 (C-24), 14.0 (C-27) ppm; MS (ESI, MeOH/CHCl 3 , 4:1): m/z = 1070 (100%, [M-Cl] + ); analysis calcd.…”

Machine Learning-Based Metabolic Pattern Recognition Predicts Mode of Action for Anti-Cancer Drug Candidates

“…Next, both ML approaches were applied to predict the MoAs of one semi-synthetic and three plant-derived drug candidates (Table S1). The novel compound AAHR, composed of triterpene asiatic acid and rhodamine B, has demonstrated robust cytotoxicity, and the capacity to conquer drug resistance in human preclinical tumor models 42,43 . In contrast to glycyrrhetinic acid (GLYA, a pure pentacyclic triterpenoid acid derived from licorice roots) AAHR has a higher toxicity towards PC-3 prostate cancer cells (Table S1).…”