cGMP production and analysis of BG505 SOSIP.664, an extensively glycosylated, trimeric HIV-1 envelope glycoprotein vaccine candidate.
Biotechnol Bioeng. 2017 Nov 18;:
Authors: Dey AK, Cupo A, Ozorowski G, Sharma VK, Behrens AJ, Go EP, Ketas TJ, Yasmeen A, Klasse PJ, Sayeed E, Desaire H, Crispin M, Wilson IA, Sanders RW, Hassell T, Ward A, Moore JP
We describe the properties of BG505 SOSIP.664 HIV-1 envelope glycoprotein trimers produced under current Good Manufacturing Practice (cGMP) conditions. These proteins are the first of a new generation of native-like trimers that are the basis for many structure-guided immunogen development programs aimed at devising how to induce broadly neutralizing antibodies (bNAbs) to HIV-1 by vaccination. The successful translation of this prototype demonstrates the feasibility of producing similar immunogens on an appropriate scale and of an acceptable quality for Phase I experimental medicine clinical trials. BG505 SOSIP.664 trimers are extensively glycosylated, contain numerous disulfide bonds and require proteolytic cleavage, all properties that pose a substantial challenge to cGMP production. Our strategy involved creating a stable CHO cell line that was adapted to serum-free culture conditions to produce envelope glycoproteins. The trimers were then purified by chromatographic methods using a 2G12 bNAb affinity column and size-exclusion chromatography. The chosen procedures allowed any adventitious viruses to be cleared from the final product to the required extent of >12 log10 . The final cGMP production run yielded 3.52 grams (peptidic mass) of fully purified trimers (Drug Substance) from a 200 L bioreactor, a notable yield for such a complex glycoprotein. The purified trimers were fully native-like as judged by negative-stain electron microscopy, and were stable over a multi-month period at room temperature or below and for at least one week at 50°C. Their antigenicity, disulfide bond patterns and glycan composition were consistent with trimers produced on a research laboratory scale. The methods reported here should pave the way for the cGMP production of other native-like Env glycoprotein trimers of various designs and genotypes. This article is protected by copyright. All rights reserved.
PMID: 29150937 [PubMed - as supplied by publisher]
Loss of HIF-1α in natural killer cells inhibits tumour growth by stimulating non-productive angiogenesis.
Nat Commun. 2017 Nov 17;8(1):1597
Authors: Krzywinska E, Kantari-Mimoun C, Kerdiles Y, Sobecki M, Isagawa T, Gotthardt D, Castells M, Haubold J, Millien C, Viel T, Tavitian B, Takeda N, Fandrey J, Vivier E, Sexl V, Stockmann C
Productive angiogenesis, a prerequisite for tumour growth, depends on the balanced release of angiogenic and angiostatic factors by different cell types within hypoxic tumours. Natural killer (NK) cells kill cancer cells and infiltrate hypoxic tumour areas. Cellular adaptation to low oxygen is mediated by Hypoxia-inducible factors (HIFs). We found that deletion of HIF-1α in NK cells inhibited tumour growth despite impaired tumour cell killing. Tumours developing in these conditions were characterised by a high-density network of immature vessels, severe haemorrhage, increased hypoxia, and facilitated metastasis due to non-productive angiogenesis. Loss of HIF-1α in NK cells increased the bioavailability of the major angiogenic cytokine vascular endothelial growth factor (VEGF) by decreasing the infiltration of NK cells that express angiostatic soluble VEGFR-1. In summary, this identifies the hypoxic response in NK cells as an inhibitor of VEGF-driven angiogenesis, yet, this promotes tumour growth by allowing the formation of functionally improved vessels.
PMID: 29150606 [PubMed - in process]
Glycyrrhiza glabra extract and quercetin reverses cisplatin resistance in triple-negative MDA-MB-468 breast cancer cells via inhibition of cytochrome P450 1B1 enzyme.
Bioorg Med Chem Lett. 2017 Nov 07;:
Authors: Sharma R, Gatchie L, Williams IS, Jain SK, Vishwakarma RA, Chaudhuri B, Bharate SB
The development of multi-drug resistance to existing anticancer drugs is one of the major challenges in cancer treatment. The over-expression of cytochrome P450 1B1 enzyme has been reported to cause resistance to cisplatin. With an objective to discover cisplatin-resistance reversal agents, herein, we report the evaluation of Glycyrrhiza glabra (licorice) extracts and its twelve chemical constituents for inhibition of CYP1B1 (and CYP1A1) enzyme in Sacchrosomes and live human cells. The hydroalcoholic extract showed potent inhibition of CYP1B1 in both Sacchrosomes as well as in live cells with IC50 values of 21 and 16 µg/mL, respectively. Amongst the total of 12 constituents tested, quercetin and glabrol showed inhibition of CYP1B1 in live cell assay with IC50 values of 2.2 and 15 µM, respectively. Both these natural products were found to be selective inhibitors of CYP1B1, and does not inhibit CYP2 and CYP3 family of enzymes (IC50 > 20 µM). The hydroalcoholic extract of G. glabra and quercetin (4) showed complete reversal of cisplatin resistance in CYP1B1 overexpressing triple negative MDA-MB-468 breast cancer cells. The selective inhibition of CYP1B1 by quercetin and glabrol over CYP2 and CYP3 family of enzymes was studied by molecular modeling studies.
PMID: 29150398 [PubMed - as supplied by publisher]