Semi-Quantitative Targeted Gas Chromatography-Mass Spectrometry Profiling Supports a Late Side-Chain Reductase Cycloartenol-to-Cholesterol Biosynthesis Pathway in Brown Algae

Sterols are biologically important molecules that serve as membrane fluidity regulators and precursors of signaling molecules, either endogenous or involved in biotic interactions. There is currently no model of their biosynthesis pathways in brown algae. Here, we benefit from the availability of genome data and gas chromatography-mass spectrometry (GC-MS) sterol profiling using a database of internal standards to build such a model. We expand the set of identified sterols in 11 species of red, brown, and green macroalgae and integrate these new data with genomic data. Our analyses suggest that some metabolic reactions may be conserved despite the loss of canonical eukaryotic enzymes, like the sterol side-chain reductase (SSR). Our findings are consistent with the principle of metabolic pathway drift through enzymatic replacement and show that cholesterol synthesis from cycloartenol may be a widespread but variable pathway among chlorophyllian eukaryotes. Among the factors contributing to this variability, one could be the recruitment of cholesterol biosynthetic intermediates to make signaling molecules, such as the mozukulins. These compounds were found in some brown algae belonging to Ectocarpales, and we here provide a first mozukulin biosynthetic model. Our results demonstrate that integrative approaches can already be used to infer experimentally testable models, which will be useful to further investigate the biological roles of those newly identified algal pathways.

Phase II study of intravenous (IV) bevacizumab and paclitaxel, and intraperitoneal (IP) cisplatin, followed by bevacizumab consolidation for advanced ovarian (O) or peritoneal (P) cancers

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Background: Excessive toxicity and difficulty in completing prescribed cycles are cited as factors behind the lack of routine acceptance of IP therapy in O/P cancer. In an effort to increase the probability of completing 6 cycles of IP therapy, we evaluated a modified IP regimen with the addition of bevacizumab to determine the proportion of patients able to receive 6 cycles successfully. Methods: An open label phase II study was conducted in patients (pts) with stage II-III O/P cancers with residual disease < 1 cm. The primary outcome measure the feasibility of delivering 6 cycles of IP therapy with a completion rate of > 80% being clinically relevant. Pts received paclitaxel 135 mg/m2 IV on day 1 followed by cisplatin 75 mg/m2 IP day 2. Bevacizumab 15 mg/kg day 1 IV was started with the second cycle. Cycles were administered every 21 days for a total of 6 cycles. Following completion of primary therapy, bevacizumab @ 15mg/kg IV was given in consolidation every 21 days for 12 cycles. Pts were assessed for toxicity and disease status. This preliminary analysis reports data from experience with 6 cycles of IP therapy. Results: 22 patients have been enrolled (21-O, 1-P) with a median age of 58 yrs. Two pts discontinued therapy due to IP port problems (following cycle 1 and 4) and per protocol, were replaced. Two pts are on active treatment (completed cycle 5). Of 20 evaluable pts, 2 pts discontinued prematurely (1 after cycle 1 due to elevated liver function tests, 1 after cycle 4 due to grade 3 neuropathy), and 1 pt received cycle 6 by IV route secondary to abdominal pain with IP infusion. The proportion of patients successfully completing 5 cycles of IP therapy was 18/20 (90%), and to date 15/18 (83%) pts have completed 6 cycles. One patient developed a DVT, one had an intra-abdominal fistula requiring surgical intervention after cycle 6. Conclusions: The addition of bevacizumab to an IP regimen for O/P cancers did not add to enhanced acute toxicity. The present regimen using 75 mg/m2 CDDP IP and no day 8 paclitaxel appears to be tolerable, with >80% of pts able to receive 6 cycles of therapy.

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