Poly-l-glutamic acid modification modulates the bio-nano interface of a therapeutic anti-IGF-1R antibody in prostate cancer.

Modifying biological agents with polymers such as polyethylene glycol (PEG) has demonstrated clinical benefits; however, post-market surveillance of PEGylated derivatives has revealed PEG-associated toxicity issues, prompting the search for alternatives. We explore how conjugating a poly-l-glutamic acid (PGA) to an anti-insulin growth factor 1 receptor antibody (AVE1642) modulates the bio-nano interface and anti-tumor activity in preclinical prostate cancer models. Native and PGA-modified AVE1642 display similar anti-tumor activity in vitro; however, AVE1642 prompts IGF-1R internalization while PGA conjugation prompts higher affinity IGF-1R binding, thereby inhibiting IGF-1R internalization and altering cell trafficking. AVE1642 attenuates phosphoinositide 3-kinase signaling, while PGA-AVE1642 inhibits phosphoinositide 3-kinase and mitogen-activated protein kinase signaling. PGA conjugation also enhances AVE1642's anti-tumor activity in an orthotopic prostate cancer mouse model, while PGA-AVE1642 induces more significant suppression of cancer cell proliferation/angiogenesis than AVE1642. These findings demonstrate that PGA conjugation modulates an antibody's bio-nano interface, mechanism of action, and therapeutic activity.

Profiling target engagement and cellular uptake of cRGD-decorated clinical-stage core-crosslinked polymeric micelles.

Polymeric micelles are increasingly explored for tumor-targeted drug delivery. CriPec® technology enables the generation of core-crosslinked polymeric micelles (CCPMs) based on thermosensitive (mPEG-b-pHPMAmLacn) block copolymers, with high drug loading capacity, tailorable size, and controlled drug release kinetics. In this study, we decorated clinical-stage CCPM with the αvß3 integrin-targeted cyclic arginine-glycine-aspartic acid (cRGD) peptide, which is one of the most well-known active targeting ligands evaluated preclinically and clinically. Using a panel of cell lines with different expression levels of the αvß3 integrin receptor and exploring both static and dynamic incubation conditions, we studied the benefit of decorating CCPM with different densities of cRGD. We show that incubation time and temperature, as well as the expression levels of αvß3 integrin by target cells, positively influence cRGD-CCPM uptake, as demonstated by immunofluorescence staining and fluorescence microscopy. We demonstrate that even very low decoration densities (i.e., 1 mol % cRGD) result in increased engagement and uptake by target cells as compared to peptide-free control CCPM, and that high cRGD decoration densities do not result in a proportional increase in internalization. In this context, it should be kept in mind that a more extensive presence of targeting ligands on the surface of nanomedicines may affect their pharmacokinetic and biodistribution profile. Thus, we suggest a relatively low cRGD decoration density as most suitable for in vivo application.

Design, development and clinical translation of CriPec®-based core-crosslinked polymeric micelles.

Nanomedicines are used to improve the efficacy and safety of pharmacotherapeutic interventions. Unraveling the biological behavior of nanomedicines, including their biodistribution and target site accumulation, is essential to establish design criteria that contribute to superior performance. CriPec® technology is based on amphiphilic methoxy-poly(ethylene glycol)-b-poly[N-(2-hydroxypropyl) methacrylamide lactate] (mPEG-b-pHPMAmLacn) block copolymers, which are designed to upon self-assembly covalently entrap active pharmaceutical ingredients (API) in core-crosslinked polymeric micelles (CCPM). Key features of CCPM are a prolonged circulation time, high concentrations at pathological sites, and low levels of accumulation in the majority of healthy tissues. Proprietary hydrolysable linkers allow for tunable and sustained release of entrapped API, including hydrophobic and hydrophilic small molecules, as well as peptides and oligonucleotides. Preclinical imaging experiments provided valuable information on their tumor and tissue accumulation and distribution, as well as on uptake by cancer, healthy and immune cells. The frontrunner formulation CPC634, which refers to 65 nm-sized CCPM entrapping the chemotherapeutic drug docetaxel, showed excellent pharmacokinetic properties, safety, tumor accumulation and antitumor efficacy in multiple animal models. In the clinic, CPC634 also demonstrated favorable pharmacokinetics, good tolerability, signs of efficacy, and enhanced localization in tumor tissue as compared to conventional docetaxel. PET imaging of radiolabeled CPC634 showed quantifiable accumulation in âˆ¼50 % of tumors and metastases in advanced-stage cancer patients, and demonstrated potential for use in a theranostic setting even when applied at a companion diagnostic dose. Altogether, the preclinical and clinical results obtained to date demonstrate that mPEG-b-pHPMAmLacn CCPM based on CriPec® technology are a potent, tunable, broadly applicable and well-tolerable platform for targeted drug delivery and improved anticancer therapy.