Stability, permeability and growth-inhibitory properties of gonadotropin-releasing hormone liposaccharides.

PURPOSE: In this study we aimed to address the poor drug-like properties of Gonadotropin-Releasing Hormone (GnRH) peptide through modification with lipids and carbohydrates. METHODS: GnRH peptide was conjugated to 2-amino-D,L-octanoic acid (C8) and 2-amino-D,L-dodecanoic acid (C12) in monomer and dimer, along with (6-9) or without (2-5 and 11) a glucose moiety. Peptides were tested for their biological activity using different tumour cell lines. The toxicity of the constructs was evaluated in peripheral blood mononuclear cells (PBMC). RESULTS: All (glyco)lipopeptides showed improved metabolic stability in Caco-2 cell homogenates. Those with single lipid moiety (2, 4 and 8) exhibited prodrug-like properties. Permeability across Caco-2 cell monolayers was enhanced in the dimer C8-modified (glyco)lipopeptide (3) and the lipopeptide with C12 inserted mid-sequence (11). Most of the constructs showed moderate-to-high antiproliferative activity against GnRH-receptor positive DU145 and OVCAR-3 cells (up to 60%). Compound 11 was the most effective with IC50 = 26.4 ± 1.07 µg.ml(-1), which was comparable to triptorelin (25.1 ± 1.14 µg.mL(-1)). The sensitivity of OVCAR-3 cells to the effect of all analogues except for 11 decreased significantly in estrogen-reconstituted media. Only compounds 2, 4, 5 and 8 showed a steroid-dependent effect in DU145 cells. No compounds exhibited significant toxicity on PBMCs. CONCLUSION: These results indicated lipidation and glycosylation improves the druggability of GnRH and could lead to an increased direct antitumour activity in some hormone dependent and independent reproductive cancers.

Active immunisation of mice with GnRH lipopeptide vaccine candidates: Importance of T helper or multi-dimer GnRH epitope.

Active immunisation against gonadotropin releasing hormone (GnRH) is a potential alternative to surgical castration. This study focused on the development of a GnRH subunit lipopeptide vaccine. A library of vaccine candidates that contained one or more (up to eight) copies of monomeric or dimeric GnRH peptide antigen, an adjuvanting lipidic moiety based on lipoamino acids, and an additional T helper epitope, was synthesised by solid phase peptide synthesis. The candidates were evaluated in vivo in order to determine the minimal components of this vaccine necessary to induce a systemic immune response. BALB/c mice were immunised with GnRH lipopeptide conjugates, co-administered with or without Complete Freund's Adjuvant, followed by two additional immunisations. Significant GnRH-specific IgG titres were detected in sera obtained from mice immunised with four of the seven lipopeptides tested, with an increase in titres observed after successive immunisations. This study highlights the importance of for epitope optimisation and delivery system design when producing anti-hapten antibodies in vivo. The results of this study also contribute to the development of future clinical and veterinary immunocontraceptives.

Genomic and Clinical Significance of Multiple Primary Lung Cancers as Determined by Next-Generation Sequencing.

INTRODUCTION: Marked variations in survival rates have brought into question whether standard clinicopathologic classification should be applied to patients presenting with multiple primary lung cancers (MPLCs). This study investigated the genetic profiles of MPLCs in a cohort of patients using next-generation sequencing and correlated results to clinicopathologic data and patient outcome. METHODS: Patients treated surgically with curative intent for two putative primaries of similar histopathology from January 2000 to December 2019 at St Vincent's Hospital Melbourne. DNA and RNA was extracted from formalin-fixed, paraffin-embedded tumor tissue and sequenced on an Ion Torrent Personal Genome Machine system. Patient outcome was determined by overall survival and disease-free survival. RESULTS: A total of 40 cases fulfilled the inclusion criteria. Mutational profiling was concordant with clinicopathologic diagnosis in most cases; however, seven cases (17.5%) revealed shared mutations suggesting metastatic disease and this was associated with a substantial reduction in overall survival (p < 0.05). CONCLUSIONS: Our results suggest that gene sequencing technologies are potentially a more accurate diagnostic and prognostic tool compared with traditional histopathologic evaluation in patients presenting with suspected MPLCs, which could better guide management and predict outcomes.

Design, synthesis and evaluation of a gonadotropin releasing hormone-based subunit vaccine in rams (Ovis aries).

Immunocastration using gonadotropin-releasing hormone (GnRH)-based vaccines has been investigated in rams to reduce aggressive and sexual behaviour and to control meat quality. Despite considerable efforts, a practical GnRH vaccine has yet to be developed for rams. In the present study, a A GnRH-lipopeptide vaccine (GnRH-LP) including two copies of GnRH, 2-amino-d,l-hexadecanoic acid (C16), and a unique T helper epitope, was examined in rams. Rams received a primary and secondary vaccination of GnRH-LP without additional adjuvant (Group 1) or with the adjuvant AdjuVac™ (Group 2). In both Group 1 and 2 anti-GnRH antibody titres increased after secondary vaccination, however, the antibody titres were higher (p<0.01) for rams in Group 2. The latter rams showed a marked decrease in testicular size. The marked and sustained reduction in testicular size in rams treated with GnRH-LP+AdjuVac™ provides the basis for an effective immunocastration vaccine in rams.

Design, synthesis and characterisation of mannosylated ovalbumin lipid core peptide self-adjuvanting vaccine delivery system.

Peptide-based vaccine delivery can be hampered by rapid peptidase activity and poor inherent immunogenicity. The self-adjuvanting lipid core peptide system (LCP) has been shown to confer improved stability and immunogenicity on peptide epitopes of group A Streptococcus, Chlamydia, hookworm, and malaria pathogens. However, various diseases, including cancer, still require targeted delivery of their vaccine candidates. For this reason, we have selected two model peptides (ovalbumin CD4(+) and/or CD8(+) T cell epitopes), and incorporated two or four copies of either epitope into our LCP vaccine. Optimised glycosylation of ovalbumin peptides yielded 46 % when microwave-assisted double coupling with 2 eq of carbohydrate derivative, activated by N,N-diisopropylethylamine and (O-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, was performed. All ovalbumin peptides were successfully synthesised and purified in 11-55 % yields by Fmoc- or Boc-chemistry using solid-phase peptide synthesis. The mannosylated ovalbumin peptides were nontoxic to human erythrocytes in haemolytic assay (<2 % haemolysis) and showed increased (up to 20-fold) stability in plasma.