Continuous intraperitoneal carboplatin delivery for the treatment of late-stage ovarian cancer

Prolonged activity of a recombinant manganese superoxide dismutase through a formulation of polymeric multi-layer nanoassemblies targeting cancer cells

A new isoform of human manganese superoxide dismutase (SOD) has been recently isolated and obtained in a synthetic recombinant form and termed rMnSOD. As compared to other SODs, this isoform exhibits a dramatically improved cellular uptake and an intense antioxidant and antitumoral activity. Unfortunately, its use is severely hampered as this active pharmaceutical ingredient (API) in solution suffers from remarkable instability, which realizes as an interplay of unfolding and aggregation phenomena. This leads the API to be ineffective after three weeks only when stored at 4°C. A formulation strategy was undertaken to mitigate this instability. This was based on the incorporation of the API in hyaluronic acid and its layer-by-layer deposition over a chitosan-n-acetyl cysteine- monolayer nanoemulsion (NE) and its subsequent coverage with a further external interface of a chitosan-n-acetyl cysteine. The obtained constructs were tested over a selected panel of healthy and cancerous cell lines. The undertaken formulation strategy enhanced the API's effect in vitro already at time zero, maintaining the efficacy of this anticancer agent until up to 30 weeks when stored at 4°C.

Pharmaceutical strategies in improving anti-tumour efficacy and safety of intraperitoneal therapy for peritoneal metastasis

Introduction: In selected patients with limited peritoneal metastasis (PM), favorable tumor biology, and a good clinical condition, there is an indication for combination of cytoreductive surgery (CRS) and subsequent intravenous (IV) or intraperitoneal (IP) chemotherapy. Compared with IV injection, IP therapy can achieve a high drug concentration within the peritoneal cavity with low systemic toxicity, however, the clinical application of IP chemotherapy is limited by the related abdominal pain, infection, and intolerance.Areas covered:To improve the anti-tumor efficacy and safety of IP therapy, various pharmaceutical strategies have been developed and show promising potential. This review discusses the specialized modification of traditional drug delivery systems and demonstrates the preparation of customized drug carriers for IP therapy, including chemotherapy and gene therapy. IP therapy has important clinical significance in the treatment of PM using novel anti-tumor agents as well as conventional drugs in new applications.Expert opinion: Although IP therapy exhibits good performance both in mouse models and in patients with PM in clinical trials, its clinical application remains limited due to the serious side effects and low acceptability. Further investigations, including pharmaceutical strategies, are needed to develop potential IP therapy, focusing on the efficacy and safety thereof.

Effects of sustained GABA releasing implants on pancreatic islets in mice

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that is strongly and selectively synthesized in and secreted from pancreatic beta cells. Exogenously delivered GABA has been proposed to induce beta cell regeneration in type 1 diabetes, but these results have been difficult to replicate and may depend on the specifics of the animal model and drug delivery method used. Here, we developed a GABA-releasing ethylene-vinyl acetate polymer implant for sustained GABA delivery to the intraperitoneal space as an alternative to injected or oral GABA. We explored the effect of the GABA-releasing polymer implants compared to implanted osmotic pumps loaded with GABA on islet size in non-diabetic, outbred mice. We also attempted to monitor in vivo GABA release using HPLC on blood samples, but these measurements were confounded by high variability within treatment groups and unexpectedly high serum GABA levels in mice receiving GABA-negative implants. The ethylene-vinyl acetate polymer implants became heavily fibrosed with abdominal adhesion tissue, while the osmotic pumps had no macroscopic fibrosis. Histological analysis showed no significant effect of the sustained GABA delivery polymer or osmotic pumps on islet size, alpha cell to beta cell ratio, or the number of Ki67-positive islet cells. The GABA treatment time course was limited to two weeks due to the drug-release window of the polymer, while others reported islet-trophic effects of GABA after 10 to 12 weeks of treatment. In summary, our study is consistent with the concept that exogenous GABA administration does not significantly alter islet cell mass in non-diabetic CD-1 mice in the short-term. However, more data are needed including higher GABA doses and more prolonged treatment regimens for a better comparison with contrasting reports.

Enhanced anti-tumor efficacy and safety with metronomic intraperitoneal chemotherapy for metastatic ovarian cancer using biodegradable nanotextile implants

The objective of this study was to evaluate intraperitoneal (IP) metronomic chemotherapy using sustained release paclitaxel (PTX) delivery from electrospun biodegradable polymeric yarns woven into suturable nanotextiles. Following confirmation of in vitro PTX efficacy in ID8-VEGF epithelial ovarian cancer cells, in vivo studies were performed upon surgical peritoneal implantation of nanotextile implants in orthotopic, syngeneic ID8-VEGF tumor-bearing C57BL/6 mice. In comparison to the clinical PTX-solution, there was a significant enhancement of anti-tumor efficacy and safety with PTX-nanotextiles. After 35-days, the peritoneum of tumor-bearing mice with PTX-nanotextiles was completely devoid of tumor nodules and ascitic fluid. Additionally, VEGF levels measured in peritoneal lavage fluid were 300-fold lower compared to PTX-solution and 600-fold lower as compared to untreated tumor-bearing animals. PTX-solution treated group also developed severe metastatic lesions and progressive ascitic fluid buildup. More importantly, no signs of systemic/ organ toxicity were observed in PTX-nanotextile implanted mice, unlike the systemic toxic effects induced by PTX-solution. Collectively, our results show the therapeutic and safety advantages offered by combining clinically translatable metronomic low-dose chemotherapy and IP pharmacokinetics using biodegradable nanotextile implants in addressing the challenges of late-stage ovarian cancer.

Rethinking Alkylating(-Like) Agents for Solid Tumor Management

Although old molecules, alkylating agents and platinum derivatives are still widely used in the treatment of various solid tumors. However, systemic toxicity and cellular resistance mechanisms impede their efficacy. Innovative strategies, including local administration, optimization of treatment schedule/dosage, synergistic combinations, and the encapsulation of bioactive molecules in smart, multifunctional drug delivery systems, have shown promising results in potentiating anticancer activity while circumventing such hurdles. Furthermore, questioning of the old paradigm according to which nuclear DNA is the critical target of their anticancer activity has shed light on subcellular alternative and neglected targets that obviously participate in the mediation of cytotoxicity or resistance. Thus, rethinking of the use of these pivotal antineoplastic agents appears critical to improve clinical outcomes in the management of solid tumors.

Continuous Delivery of Neutralizing Antibodies Elevate CCL2 Levels in Mice Bearing MCF10CA1d Breast Tumor Xenografts

Chemokines are small soluble molecules that play critical roles in wound healing, infection, and cancer progression. In particular, overexpression of the C-C motif chemokine ligand 2 (CCL2) in multiple cancer types correlates with poor patient prognosis. Animal studies have shown that CCL2 signals to macrophages and breast cancer cells to promote tumor growth, invasion, and metastasis, indicating that CCL2 is a promising therapeutic target. However, the effectiveness of human-specific neutralizing antibodies has not been fully evaluated. Furthermore, controversies remain on the use of neutralizing antibodies to target CCL2 and could be due to mode of drug delivery. Here, we investigated the effects of continuous delivery of human CCL2-neutralizing antibodies on breast cancer progression. Nude mice bearing MCF10CA1d breast tumor xenografts were implanted with osmotic pumps containing control IgG or anti-CCL2 and analyzed for CCL2 levels and tumor progression over 4 weeks. Despite inhibiting CCL2-induced migration in vitro, CCL2-neutralizing antibodies did not significantly affect tumor growth, invasion, macrophage recruitment, or tumor angiogenesis. CCL2 antibodies did not affect murine CCL2 levels but significantly increased human CCL2 levels in circulating blood and tumor interstitial fluid. CCL2-neutralizing antibodies reduced CCL2 levels in cultured cells short term at high concentrations. Enzyme-linked immunosorbent assay analysis of CCL2 in cultured fibroblasts and breast cancer cells revealed that the neutralizing antibodies sequestered CCL2 in the media. CCL2 levels were restored once the antibodies were removed. These studies reveal limitations in CCL2-neutralizing antibodies as a therapeutic agent, with important implications for translating CCL2 targeting to the clinic.

New Role for FDA-Approved Drugs in Combating Antibiotic-Resistant Bacteria

Antibiotic resistance in medically relevant bacterial pathogens, coupled with a paucity of novel antimicrobial discoveries, represents a pressing global crisis. Traditional drug discovery is an inefficient and costly process; however, systematic screening of Food and Drug Administration (FDA)-approved therapeutics for other indications in humans offers a rapid alternative approach. In this study, we screened a library of 780 FDA-approved drugs to identify molecules that rendered RAW 264.7 murine macrophages resistant to cytotoxicity induced by the highly virulent Yersinia pestis CO92 strain. Of these compounds, we identified 94 not classified as antibiotics as being effective at preventing Y. pestis-induced cytotoxicity. A total of 17 prioritized drugs, based on efficacy in in vitro screens, were chosen for further evaluation in a murine model of pneumonic plague to delineate if in vitro efficacy could be translated in vivo Three drugs, doxapram (DXP), amoxapine (AXPN), and trifluoperazine (TFP), increased animal survivability despite not exhibiting any direct bacteriostatic or bactericidal effect on Y. pestis and having no modulating effect on crucial Y. pestis virulence factors. These findings suggested that DXP, AXPN, and TFP may modulate host cell pathways necessary for disease pathogenesis. Finally, to further assess the broad applicability of drugs identified from in vitro screens, the therapeutic potential of TFP, the most efficacious drug in vivo, was evaluated in murine models of Salmonella enterica serovar Typhimurium and Clostridium difficile infections. In both models, TFP treatment resulted in increased survivability of infected animals. Taken together, these results demonstrate the broad applicability and potential use of nonantibiotic FDA-approved drugs to combat respiratory and gastrointestinal bacterial pathogens.