Drug conjugation to hyaluronan widens therapeutic indications for ovarian cancer

Management of ovarian cancer still requires improvements in therapeutic options. A drug delivery strategy was tested that allows specific targeting of tumor cells in combination with a controlled release of a cytotoxic molecule. To this aim, the efficacy of a loco-regional intraperitoneal treatment with a bioconjugate (ONCOFID-S) derived by chemical linking of SN-38, the active metabolite of irinotecan (CPT-11), to hyaluronan was assessed in a mouse model of ovarian carcinomatosis. In vitro, the bioconjugate selectively interacted with ovarian cancer cells through the CD44 receptor, disclosed a dose-dependent tumor growth inhibition efficacy comparable to that of free SN-38 drug, and inhibited Topoisomerase I function leading to apoptosis by a mechanism involving caspase-3 and -7 activation and PARP cleavage. In vivo, the intraperitoneal administration of ONCOFID-S in tumor-bearing mice did not induce inflammation, and evidenced an improved therapeutic efficacy compared with CPT-11. In conclusion, SN-38 conjugation to hyaluronan significantly improved the profile of in vivo tolerability and widened the field of application of irinotecan. Therefore, this approach can be envisaged as a promising therapeutic strategy for loco-regional treatment of ovarian cancer

A site-selective hyaluronan-interferonα2a conjugate for the treatment of ovarian cancer

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Conjugation of hyaluronan to proteins

Polymer conjugation has been widely exploited to prolong half-life and reduce immunogenicity of therapeutic proteins. Here, the potentials of hyaluronic acid (HA) have been investigated by studying the conjugates with two model enzymes, trypsin and RNase A, and with insulin. As the direct coupling of proteins to the HA\u2019s carboxylic groups can cause cross-linking problems, a hyaluronan-aldehyde derivative has been synthesized for N-terminal site-selective conjugation. HA conjugation, termed HAylation, preserved the activities of enzymes and their thermal stabilities. Insulin HAylation was studied by preparing two conjugates with different peptide loadings (32% and 17%, w/w). Noticeably, the conjugate with the lower loading showed the greater effect on blood glucose level. The 17% HA-insulin conjugate showed a lowering effect on blood glucose level for up to 6 h, while free insulin exhausted its action after 1 h. This study highlights the potentials of hyaluronan-aldehyde for protein delivery

Hyaluronan as carrier of carboranes for tumor targeting in boron neutron capture therapy

Boron neutron capture therapy (BNCT) represents a promising approach for tumor therapy. A critical requirement for BNCT is tumor targeting, a goal that is currently addressed with the development of low and high molecular weight agents capable of interacting with receptors expressed by cancer cells. Here, we describe a new bioconjugate (HApCB) composed by n-propyl carborane linked to hyaluronan (HA) via an ester linkage for a degree of substitution of approximately 30%, leading to a water-soluble derivative. The structure and main physicochemical characteristics of the new HA derivative were determined by means of Fourier transform infrared, fluorescence, and 1H, 13C, and 10B NMR analysis and are herein reported in detail. As HA is recognized by the CD44 antigen, densely populating the surface of many tumor cells, HApCB is expected to deliver boron atoms from the locally released carborane cages directly to target cells for antitumor application in BNCT. In vitro biological experiments showed that HApCB was not toxic for a variety of human tumor cells of different histotypes, specifically interacted with CD44 as the native unconjugated HA, and underwent uptake by tumor cells, leading to accumulation of amounts of boron atoms largely exceeding those required for a successful BNCT approach. Thus, HApCB may be regarded as a promising new BNCT agent for specific targeting of cancer cells overexpressing the CD44 receptor

Drug conjugation to hyaluronan widens therapeutic indications for ovarian cancer

ABSTRACT Management of ovarian cancer still requires improvements in therapeutic In vitro, the bioconjugate selectively interacted with ovarian cancer cells through the CD44 receptor, disclosed a dose-dependent tumor growth inhibition efficacy comparable to that of free SN-38 drug, and inhibited Topoisomerase I function leading to apoptosis by a mechanism involving caspase-3 and -7 activation and PARP cleavage. In vivo, the intraperitoneal administration of ONCOFID-S in tumor-bearing mice did not induce inflammation, and evidenced an improved therapeutic efficacy compared with CPT-11. In conclusion, SN-38 conjugation to hyaluronan significantly improved the profile of in vivo tolerability and widened the field of application of irinotecan. Therefore, this approach can be envisaged as a promising therapeutic strategy for loco-regional treatment of ovarian cancer

A new and simply available class of hydrosoluble bioconjugates by coupling paclitaxel to hyaluronic acid through a 4-hydroxybutanoic acid derived linker

A simple preparation of a new hydrosoluble paclitaxel bioconjugate 8, representing a new class of paclitaxel derivatives, is described. Bioconjugate 8 was obtained by coupling hyaluronic acid (2) to paclitaxel (1) by means of a 4-hydroxybutanoic acid derived linker (Scheme 2)

The in vitro rabbit whole bladder as a model to investigate the urothelial transport of anticancer agents The ONCOFID-P paradigm.

Intravesical instillation of BCG or anticancer agents after transurethral resection is currently considered a standard of therapy. However, this approach is basically empirical; none of the anticancer agents used in this setting was specifically formulated for intravesical therapy. Moreover, concern is raised by the kinetic features of water soluble drugs, because of poor transport across the mucosal barrier, or of liphophylic compounds, for the increased risks of systemic toxicity. A need exists to improve the pre-clinical and clinical approaches used at present to test anticancer agents undergoing specific development for intravesical use. We used in vitro rabbit whole bladders as a new pre-clinical model to investigate the kinetics of locally administered anticancer agents. In this study, we investigated the rate of urothelial transport of a novel paclitaxel derivative, Oncofid-P. Male New Zealand albino rabbits were used. Bladders were rapidly explanted, filled with vehicle alone or vehicle containing graded concentrations of Oncofid-P, and kept for various times under standardized incubation conditions. At the end of experiments, drug concentrations were assessed by high-pressure-liquid-chromatography technique in the intravesical and external bath solutions, as well as in bladder wall homogenates. We found that less than 1% of the drug additioned to the intravesical solution is recovered within the bladder wall in the form of paclitaxel; experiments carried out collecting different areas from the same bladders showed that Oncofid-P is uniformly distributed over the internal surface of bladder mucosa. Isolated rabbit bladders may be a useful pre-clinical model to investigate the rate of transport of chemotherapeutic agents administered by intravesical route. In this paradigm, Oncofid-P displays a kinetic profile that is predictive of local activity over the whole urothelial surface, and low or absent systemic absorption

Confocal microscopy analysis and co-localization studies.

<p>A, accumulation of bioconjugates in HT-29, MKN-45 and KYSE-30. Cells were incubated with BODIPY-labeled ONCOFID-P (50 µg/mL in paclitaxel equivalents) or ONCOFID-S (50 µg/mL in SN-38 equivalents) for 1 hour, washed and fixed before analysis. B, co-localization analysis of bioconjugates in lysosomes. HT-29, MKN-45 and OE-33 cells were treated with LysoTracker green, incubated with BODIPY-labeled compounds and finally analyzed by confocal microscopy. Left pictures show the fluorescence of the labeled bioconjugates (red) in single cells, while central pictures illustrate signals (green) from lysosomes. The merging of the 2 components is visible in right pictures. Lysosomes were occupied by bioconjugates by ∼90% to 100%, as assessed by the Zeiss’profile software tool. Experiments were repeated at least twice with consistent results.</p