Therapeutic Potential of Fosmanogepix (APX001) for Intra-abdominal Candidiasis: from Lesion Penetration to Efficacy in a Mouse Model.

Intra-abdominal candidiasis (IAC) is one of the most common yet underappreciated forms of invasive candidiasis. IAC is difficult to treat, and therapeutic failure and drug-resistant breakthrough infections are common in some institutions despite the use of echinocandins as first-line agents. Fosmanogepix (FMGX, formerly APX001) is a first-in-class antifungal prodrug that can be administered both intravenously and orally. FMGX is currently in phase 2 clinical development for the treatment of life-threatening invasive fungal infections. To explore the pharmacological properties and therapeutic potential of FMGX for IAC, we evaluated both drug penetration and efficacy of the active moiety manogepix (MGX, formerly APX001A) in liver tissues in a clinically relevant IAC mouse model infected with Candida albicans Matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) and laser capture microdissection (LCM)-directed absolute drug quantitation were employed to evaluate drug penetration into liver abscess lesions both spatially and quantitatively. The partitioning of MGX into lesions occurred slowly after a single dose; however, robust accumulation in the lesion was achieved after 3 days of repeated dosing. Associated with this drug penetration pattern, reduction in fungal burden and clearance in the liver were observed in mice receiving the multiday FMGX regimen. In comparison, administration of micafungin resulted in marginal reduction in fungal burden at the end of 4 days of treatment. These results suggest that FMGX is a promising candidate for the treatment of IAC.

A simple, reliable method for high-throughput screening for diabetes drugs using 3D ß-cell spheroids.

Early screens for new diabetes drugs rely on monolayers of ß-cells, which are known to be poor predictors of the in vivo response. Previously, we developed a method to create uniform islet spheroids from freshly-dispersed human donor tissue for drug screening. While the human engineered islets worked well to reduce donor-to-donor variability, it is difficult and expensive to obtain sufficient high-quality human islets for drug testing. Thus, this study utilized a genetically-modified ß-cell culture line (INS-1832/13) in 2D and as 3D spheroids and compared the results to human islet tissue formed into spheroids using a high-throughput 384-well format. In response to increasing concentrations of glucose, all 3 groups increased insulin release, but the cultured ß-cells (2D and 3D) were more sensitive to glucose (EC50 5.85mM for 2D ß-cells, 16.24mM for 3D ß-cell spheroids) than the human islet spheroids (EC50 53.69mM). The order of responses to glybenclamide was human spheroids >3D ß-cell culture >2D ß-cell culture. In response to caffeine, the ß-cells in 2D or 3D were more responsive compared to the human islet spheroids (EC50 0.39 and 0.31mM for 2D and 3D ß-cells respectively). When exposed to inhibitors of insulin secretion (nifedipine and diazoxide), the responses were more similar between groups. Z' calculations, indicative of assay quality, determined that the 3D ß-cell spheroids reached the criteria of an excellent to ideal drug screen assay more consistently than the other test models. In conclusion, 3D ß-cell spheroids from a cultured cell line can be used in HTS assays that, according to reference drugs tested here, are sensitive and predictive of the in vivo response.

Arum Palaestinum with isovanillin, linolenic acid and ß-sitosterol inhibits prostate cancer spheroids and reduces the growth rate of prostate tumors in mice.

BACKGROUND: Arum palaestinum is a plant commonly found in the Middle East that is ingested as an herbal remedy to fight cancer. However, no studies have examined the direct effect of the plant/plant extract on tumor growth in an animal model. METHODS: Verified prostate cancer cells were plated as 3D spheroids to determine the effect of extract from boiled Arum Palaestinum Boiss roots. In addition, male NU/NU mice (8 weeks old) with xenograft tumors derived from the prostate cancer cell line were treated daily with 1000 mg/kg body weight gavage of the suspension GZ17. The tumor growth was measured repeatedly with calipers and the excised tumors were weighed at the termination of the 3 week study. Control mice (10 mice in each group) received vehicle in the same manner and volume. RESULTS: The number of live prostate cancer cells declined in a dose/dependent manner with a 24 h exposure to the extract at doses of 0.015 to 6.25 mg/mL. A fortified version of the extract (referred to as GZ17) that contained higher levels of isovanillin, linolenic acid and ß-sitosterol had a stronger effect on the cell death rate, shifting the percentage of dead cells from 30 % to 55 % at the highest dose while the vehicle control had no effect on cell numbers. When GZ17 was applied to non-cancer tissue, in this case, human islets, there was no cell death at doses that were toxic to treated cancer cells. Preliminary toxicity studies were conducted on rats using an up-down design, with no signs of toxic effect at the highest dose. NU/NU mice with xenograft prostate tumors treated with GZ17 had a dramatic inhibition of tumor progression, while tumors in the control group grew steadily through the 3 weeks. The rate of tumor volume increase was 73 mm(3)/day for the vehicle group and 24 mm(3)/day for the GZ17 treated mice. While there was a trend towards lower excised tumor weight at study termination in the GZ17 treatment group, there was no statistical difference. CONCLUSIONS: Fortified Arum palaestinum Boiss caused a reduction in live cells within prostate cancer spheroids and blocked tumor growth in xenografted prostate tumors in mice without signs of toxicity.