A monocyte-keratinocyte-derived co-culture assay accurately identifies efficacies of BET inhibitors as therapeutic candidates for psoriasiform dermatitis

BACKGROUND

Bromodomain and extra-terminal (BET) proteins perform key roles in epigenetic control of gene expression that is involved in inflammatory conditions, including psoriasiform dermatitis (PsD). Predicting which (of many potential available BET inhibitors) will be effective in vivo is challenging.

OBJECTIVE

We determine if a novel in vitro assay that includes two critical cell types involved in human psoriasis can predict the therapeutic potential of specific BET inhibitors in vivo.

METHODS

An in vitro model consisting of U-937 and HaCaT cell co-culture was created to screen small molecule BET antagonists for inhibition of cutaneous inflammatory genes. Efficacious BET inhibitors were tested in a mouse imiquimod (IMQ)-induced PsD model.

RESULTS

In the co-culture system, HaCaT cells exhibited a marked increase in the secretion of a characteristic set of proinflammatory and Th17-associated cytokines. Of the ten commercially-available small molecules targeting BET proteins assayed, most compounds exhibited inhibitory functions at 1 μM against inflammatory activation, but responded variably at lower concentrations. OTX015, a typical representative for most of the compounds, barely inhibited the inflammatory reactions at 0.1 μM. By contrast, ABBV075 was effective in concentrations as low as 0.01 μM. While oral administration OTX015 in IMQ-treated mice reduced disease severity, ABBV075 equally decreased the symptoms and molecular and cellular severity markers at one-tenth of the minimal dosing required for OTX015.

CONCLUSION

In vitro screening system combined with an in vivo animal model, can serve as a convenient pre-clinical screening tool for the selection of BET inhibitors (and possibly other drugs) that may have clinical potential in psoriasis therapy.

Therapeutic Potential of 47Sc in Comparison to 177Lu and 90Y: Preclinical Investigations

Targeted radionuclide therapy with ¹⁷⁷Lu- and ⁹⁰Y-labeled radioconjugates is a clinically-established treatment modality for metastasized cancer. ⁴⁷Sc is a therapeutic radionuclide that decays with a half-life of 3.35 days and emits medium-energy β⁻-particles. In this study, ⁴⁷Sc was investigated, in combination with a DOTA-folate conjugate, and compared to the therapeutic properties of ¹⁷⁷Lu-folate and ⁹⁰Y-folate, respectively. In vitro, ⁴⁷Sc-folate demonstrated effective reduction of folate receptor-positive ovarian tumor cell viability similar to ¹⁷⁷Lu-folate, but ⁹⁰Y-folate was more potent at equal activities due to the higher energy of emitted β⁻-particles. Comparable tumor growth inhibition was observed in mice that obtained the same estimated absorbed tumor dose (~21 Gy) when treated with ⁴⁷Sc-folate (12.5 MBq), ¹⁷⁷Lu-folate (10 MBq), and ⁹⁰Y-folate (5 MBq), respectively. The treatment resulted in increased median survival of 39, 43, and 41 days, respectively, as compared to 26 days in untreated controls. There were no statistically significant differences among the therapeutic effects observed in treated groups. Histological assessment revealed no severe side effects two weeks after application of the radiofolates, even at double the activity used for therapy. Based on the decay properties and our results, ⁴⁷Sc is likely to be comparable to ¹⁷⁷Lu when employed for targeted radionuclide therapy. It may, therefore, have potential for clinical translation and be of particular interest in tandem with ⁴⁴Sc or ⁴³Sc as a diagnostic match, enabling the realization of radiotheragnostics in future.

Docetaxel and gemcitabine activity in NSCLC cell lines and in primary cultures from human lung cancer

The activity of the following drugs was investigated in two established NSCLC cell lines: docetaxel, gemcitabine, vinorelbine, paclitaxel, doxorubicin (0.01, 0.1, 1 microg ml(-1)), cisplatin, ifosfamide (1, 2, 3 microg ml(-1)) and carboplatin (2, 4, 6 microg ml(-1)). The cytotoxic activity was evaluated by the sulphorhodamine B assay. The two most active drugs, docetaxel and gemcitabine, used singly and in association, were investigated as a function of treatment schedule. The sequence docetaxel-->gemcitabine produced only a weak synergistic interaction in RAL but a strong synergism in CAEP cells. The synergistic interaction increased in both cell lines after a 48-h washout between the drug administrations. Flow cytometric analysis showed that in docetaxel-->gemcitabine sequence, docetaxel produced a block in G2/M phase and, after 48 h, provided gemcitabine with a large fraction of recovered synchronized cells in the G1/S boundary, which is the specific target phase for gemcitabine. Conversely, simultaneous treatment induced an antagonistic effect in both cell lines, and the sequential scheme gemcitabine-->docetaxel produced a weak synergistic effect only in RAL cells. Moreover, the synergistic interaction disappeared when washout periods of 24 or 48 h between two drug administrations were adopted. The synergistic activity of docetaxel-->48-h washout-->gemcitabine was confirmed in 11 of 14 primary cultures, which represents an important means of validating experimental results before translating them into clinical practice.