Spontaneously-forming spheroids as anin vitrocancer cell model for anticancer drug screening

Abstract

The limited translational value in clinic of analyses performed on 2-D cell cultures has prompted a shift toward the generation of 3-dimensional (3-D) multicellular systems. Here we present a spontaneously-forming in vitro cancer spheroid model, referred to as spheroidsMARY-X, that precisely reflects the pathophysiological features commonly found in tumor tissues and the lymphovascular embolus. In addition, we have developed a rapid, inexpensive means to evaluate response following drug treatment where spheroid dissolution indices from brightfield image analyses are used to construct dose-response curves resulting in relevant IC50 values. Using the spheroidsMARY-X model, we demonstrate the unique ability of a new class of molecules, containing the caged Garcinia xanthone (CGX) motif, to induce spheroidal dissolution and apoptosis at IC50 values of 0.42 +/−0.02 μM for gambogic acid and 0.66 +/−0.02 μM for MAD28. On the other hand, treatment of spheroidsMARY-X with various currently approved chemotherapeutics of solid and blood-borne cancer types failed to induce any response as indicated by high dissolution indices and subsequent poor IC50 values, such as 7.8 +/−3.1 μM for paclitaxel. Our studies highlight the significance of the spheroidsMARY-X model in drug screening and underscore the potential of the CGX motif as a promising anticancer pharmacophore.

Caged Garcinia Xanthones, a Novel Chemical Scaffold with Potent Antimalarial Activity

“…2, GBA and CLV exhibited moderate antimalarial activities with EC 50 s of 0.28 Ϯ 0.03 and 0.75 Ϯ 0.03 M, respectively. Similar antimalarial activity was observed with MAD28, the C 6 -hydroxylated CLV, which exhibited an EC 50 of 0.26 Ϯ 0.02 M. However, MAD44, the C 18 -hydroxylated CLV, was less effective, with an EC 50 of 4.1 Ϯ 0.3 M. CR135 and CR142 were synthesized from MAD28 and MAD44, respectively, by conjugating a triphenylphosphonium group at C 6 of MAD28 and C 18 of MAD44 (38). Importantly, CR135 and CR142 exhibited remarkable antimalarial activities, with EC 50 s as low as 7.9 and 11.1 nM, respectively.…”

“…4), indicating that the parasite mitochondrion contains at least one target of CR135 and CR142. Interestingly, in cancer cells, both CR135 and CR142 showed lower toxicity than their parent compounds, MAD28 and MAD44 (38), suggesting that structural modifications of the CGX motif could improve both potency and selectivity against malaria parasites. Besides the triphenylphosphonium group, the caged xanthone moiety of CR135 and CR142 is also critical for function, since SQ129, a synthetic derivative that contains a triphenylphosphonium group but lacks the caged xanthone, showed only moderate antimalarial activity.…”

“…The synthesis of the triphenylphosphonium salt conjugates is described in the supplemental material. CR135 and CR142 were synthesized from MAD28 and MAD44, respectively, by treating them with 1,4-dibromobutane (5 eq) and potassium carbonate (2 eq) in dimethylformamide (38). The resulting bromide was then converted to the triphenylphosphonium salt upon treatment with triphenylphosphine (Ph 3 P; 5 eq) in acetonitrile at 150°C under microwave irradiation.…”

Gambogic acid identifies an isoform-specific druggable pocket in the middle domain of Hsp90β

“…GBA (43), Bio-GBA (58), and MAD28 (52)(53)(54)59) were synthesized as previously described. Cell Lines and Transfection.…”

Cell spheroids: the new frontiers in in vitro models for cancer drug validation

“…The nanoimprinting 3D culture technology provides an easy-handling highthroughput drug screening system, which enables efficient drug development by mimicking the tumor environment [48]; and imaging-based 3D models in the early stages of drug development generate biologically relevant data, increasing their successful application in human studies [49]. Finally, using a spontaneously forming spheroid model, spheroids(MARY-X), a new class of molecules containing the caged Garcinia xanthone (CGX) motif is able to induce spheroidal dissolution and apoptosis, relevant in drug screening and depicting the potential of the CGX motif as a promising anticancer pharmacophore [50]. These spheroids are shown to mimic the in vivo M a n u s c r i p t 9 metastatic efficiency and progress, and the intratumoral biological and biochemical complexities.…”