In vitro and in vivo antifungal activities of the eight steroid saponins from Tribulus terrestris L. with potent activity against fluconazole-resistant fungal pathogens

Antifungal activity of natural products is being studied widely. Saponins are known to be antifungal and antibacterial. We have isolated eight steroid saponins from Tribulus terrestris L. , namely TTS-8, TTS-9, TTS-10, TTS-11, TTS-12, TTS-13, TTS-14 and TTS-15. TTS-12 and TTS-15 were identified as tigogenin-3-O-β-D-xylopyranosyl（1→ 2）-[-β-D-xylopyranosyl（ 1 → 3 ） 3-β- D-glucopyranosyl （ 1 → 4 ）- 1- α-L-rhamnopyranosyl （ 1 → 2 ） 3-β-D-galactopyranoside and tigogenin-3-O-β-D-glucopyranpyranosyl（1→2）-[-β-D-xylopyranosyl（1→ 3）3-β-D-glucopyranosyl（1→4）-β-D-galactopyranoside, respectively. The in vitro antifungal activities of the eight saponins against six fluconazole-resistant yeasts, Candida albicans, Candida glabrata, Candida para psilosis , Candida tropicalis , Candida krusei , and Cryptococcus neo f ormans were studied using microbroth dilution assay. The results showed that TTS-12 and TTS-15 were very effective against several pathogenic candidal species and C. neoformans in vitro. It is noteworthy that TTS-12 and TTS-15 were very active against fluconazole-resistant C. albicans （MIC80 = 4.4, 9.4 mg/ml）, C. neoformans （MIC80 =10.7, 18.7 mg/ml） and inherently resistant C. krusei （MIC80 =8.8, 18.4 mg/ml）. So in vivo activity of TTS-12 in a vaginal infection model with fluconazole-resistant C. albicans was studied in particular. Our studies revealed TTS-12 also showed in vivo activities against fluconazole-resistant yeasts. In conclusion, steroid saponins TTS-12 and TTS-15 from Tribulus terrestris L. have significant in vitro antifungal activity against fluconazole-resistant fungi, especially TTS-12 also showed in vivo activity against fluconazole-resistant C. albicans.     

Clinical evaluation of ZD6474, an orally active inhibitor of VEGF and EGF receptor signaling, in patients with solid, malignant tumors.

BACKGROUND: ZD6474 selectively inhibits the tyrosine kinase activity of vascular endothelial growth factor receptor and epidermal growth factor receptor. The safety, tolerability and pharmacokinetics of ZD6474 were assessed in a phase I dose-escalation study of patients with advanced solid tumors. PATIENTS AND METHODS: Adult patients with tumors refractory to standard treatments received once-daily oral ZD6474 (50-600 mg) in 28-day cycles, until disease progression or unacceptable toxicity was observed. RESULTS: Seventy-seven patients were treated at doses of 50 mg (n=9), 100 mg (n=19), 200 mg (n=8), 300 mg (n=25), 500 mg (n=8), and 600 mg (n=8). Adverse events were generally mild, and the most common dose-limiting toxicities (DLT) were diarrhea (n=4), hypertension (n=4), and rash (n=3). The incidence of most adverse events appeared to be dose-dependant. In the 500 mg/day cohort, 3/8 patients experienced DLT and this dose was therefore considered to exceed the maximum tolerated dose. Pharmacokinetic analysis confirmed that ZD6474 was suitable for once-daily oral dosing. CONCLUSIONS: Once-daily oral dosing of ZD6474 at 300 mg/day is generally well tolerated in patients with advanced solid tumors, and this dose is being investigated in phase II trials.     

A NOTCH1 gene copy number gain is a prognostic indicator of worse survival and a predictive biomarker to a Notch1 targeting antibody in colorectal cancer

Dysregulation of the Notch1 receptor has been shown to facilitate the development and progression of colorectal cancer (CRC) and has been identified as an independent predictor of disease progression and worse survival. Although mutations in the NOTCH1 receptor have not been described in CRC, we have previously discovered a NOTCH1 gene copy number gain in a portion of CRC tumor samples. Here, we demonstrated that a NOTCH1 gene copy number gain is significantly associated with worse survival and a high percentage of gene duplication in a cohort of patients with advanced CRC. In our CRC patient‐derived tumor xenograft (PDTX) model, tumors harboring a NOTCH1 gain exhibited significant elevation of the Notch1 receptor, JAG1 ligand and cleaved Notch1 activity. In addition, a significant association was identified between a gain in NOTCH1 gene copy number and sensitivity to a Notch1‐targeting antibody. These findings suggest that patients with metastatic CRC that harbor a gain in NOTCH1 gene copy number have worse survival and that targeting this patient population with a Notch1 antibody may yield improved outcomes.