Photodynamic therapy (PDT) is a promising treatment strategy where activation of photosensitizer drugs with specific wavelengths of light results in energy transfer cascades that ultimately yield cytotoxic reactive oxygen species which can render apoptotic and necrotic cell death. Without light the photosensitizer drugs are minimally toxic and the photoactivating light itself is non-ionizing. Therefore, harnessing this mechanism in tumors provides a safe and novel way to selectively eradicate tumor with reduced systemic toxicity and side effects on healthy tissues. For successful PDT of solid tumors, it is necessary to ensure tumor-selective delivery of the photosensitizers, as well as, the photoactivating light and to establish dosimetric correlation of light and drug parameters to PDT-induced tumor response. To this end, the nanomedicine approach provides a promising way towards enhanced control of photosensitizer biodistribution and tumor-selective delivery. In addition, refinement of nanoparticle designs can also allow incorporation of imaging agents, light delivery components and dosimetric components. This review aims at describing the current state-of-the-art regarding nanomedicine strategies in PDT, with a comprehensive narrative of the research that has been carried out in vitro and in vivo, with a discussion of the nanoformulation design aspects and a perspective on the promise and challenges of PDT regarding successful translation into clinical application.

The invasion of tumor cells into brain tissue is a pathologic hallmark of malignant gliomas and contributes to treatment failures. Diffuse glioblastomas contain numerous microglial cells, which enhance the progression of gliomas; however, factors responsible for invasionpromoting role of microglia are unknown. Transforming growth factor-b (TGF-b) can enhance tumor growth, invasion, angiogenesis and immunosuppression. Antagonizing TGF-b activity has been shown to inhibit tumor invasion in vitro and tumorigenicity, but a systemic inhibition or lack of TGF-b signaling results in acute inflammation and disruption of immune system homeostasis. We developed plasmid-transcribed small hairpin RNAs (shRNAs) to downregulate the TGF-b type II receptor (TbIIR) expression, which effectively inhibited cytokine-induced signaling pathways and transcriptional responses in transiently transfected human glioblastoma cells. Silencing of TbIIR abolished TGF-b-induced glioblastoma invasiveness and migratory responses in vitro. Moreover, tumorigenicity of glioblastoma cells stably expressing TbIIR shRNAs in nude mice was reduced by 50%. Microglia strongly enhanced glioma invasiveness in the co-culture system, but this invasion-promoting activity was lost in glioma cells stably expressing shTbRII, indicating a crucial role of microglia-derived TGF-b in tumor-host interactions. Our results demonstrate a successful targeting of TGF-b-dependent invasiveness and tumorigenicity of glioblastoma cells by RNAi-mediated gene silencing.

The paper describes the concept of magneto-mechanical actuation of single-domain magnetic nanoparticles (MNPs) in super-low and low frequency alternating magnetic fields (AMFs) and its possible use for remote control of nanomedicines and drug delivery systems. The applications of this approach for remote actuation of drug release as well as effects on biomacromolecules, biomembranes, subcellular structures and cells are discussed in comparison to conventional strategies employing magnetic hyperthermia in a radio frequency (RF) AMF. Several quantitative models describing interaction of functionalized MNPs with single macromolecules, lipid membranes, and proteins (e.g. cell membrane receptors, ion channels) are presented. The optimal characteristics of the MNPs and an AMF for effective magneto-mechanical actuation of single molecule responses in biological and bio-inspired systems are discussed. Altogether, the described studies and phenomena offer opportunities for the development of novel therapeutics both alone and in combination with magnetic hyperthermia.

Motion of micron and sub-micron size magnetic particles in alternating magnetic fields can activate mechanosensitive cellular functions or physically destruct cancer cells. However, such effects are usually observed with relatively large magnetic particles (>250 nm) that would be difficult if at all possible to deliver to remote sites in the body to treat disease. Here we show a completely new mechanism of selective toxicity of superparamagnetic nanoparticles (SMNP) of 7 to 8 nm in diameter to cancer cells. These particles are coated by block copolymers, which facilitates their entry into the cells and clustering in the lysosomes, where they are then magneto-mechanically actuated by remotely applied alternating current (AC) magnetic fields of very low frequency (50 Hz). Such fields and treatments are safe for surrounding tissues but produce cytoskeletal disruption and subsequent death of cancer cells while leaving healthy cells intact.

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The ‘nanomedicine’ approach has revolutionized cancer therapy by enabling the packaging of therapeutic agents within engineered nanovehicles that can specifically accumulate within the tumor stroma and then be internalized within cancer cells, to render site-selective action while minimizing nonspecific uptake and harmful side effects. While the specific accumulation within the tumor stroma is rendered by the ability of the nanovehicles to passively permeate through the tumor’s leaky vasculature, the cellular internalization is often achieved by exploiting receptor-mediated active endocytotic mechanisms using receptor-specific ligand decoration on the vehicle surface. To this end, a highly important receptor found in several cancers is the EGF receptor, which has been implicated in tumor aggression and proliferation. In this context, we provide a comprehensive review of the various approaches of ligand decorations on nanovehicles for active targeting to EGF receptors, and discuss their pros and cons towards optimizing the design of EGF receptor-targeted nanomedicine systems.

In photodynamic therapy (PDT), the light-activation of a photosensitizer leads to the generation of reactive oxygen species that can trigger various mechanisms of cell death. Harnessing this process within cancer cells enables minimally invasive yet targeted cancer treatment. With this rationale, here we demonstrate tumor-targeted delivery of a highly hydrophobic photosensitizer Pc 4 loaded within biocompatible PEG-PCL block-copolymer micelles. The micelles were surface-modified with EGFR-targeting GE11-peptides for active targeting of EGFR-overexpressing cancer cells, in vitro. Pc 4-loaded EGFR-targeted micelles were incubated with EGFR-overexpressing A431 epidermoid carcinoma cells for various time periods, to determine Pc 4 uptake by epifluorescence microscopy. The cells were subsequently photoirradiated and PDT-induced cell death for various incubation periods was determined by MTT assay and fluorescence Live/Dead assay. Our results indicate that active EGFR-targeting of the Pc 4-loaded micelles accelerates intracellular uptake of the drug. Consequently this enhances the PDT-induced cytotoxicity within shorter time periods.

Effective chimeric antigen receptor (CAR)-T cell therapy is dependent on optimal cell culture methods conducive to the activation and expansion of T cells ex vivo , as well as infection with CAR. Media formulations used in CAR-T cell manufacturing have not been optimized for gene delivery, cell expansion, and overall potency. Bioactive components and derivatives that support the generation of functionally-competent T cell progeny with long-lasting persistence are largely undefined. Current media formulations rely on fetal bovine serum (FBS) or human serum (HS), which suffer from a lack of consistency or supply issues. We recognize that components of blood cellular fractions that are absent in serum may have therapeutic value. Here we investigate whether a concentrated growth factor extract, purified from human transfusion grade whole blood fractions, and marketed as PhysiologixTM xeno-free (XF) hGFC (Phx), supports CAR-T cell expansion and function. We show that Phx supports T cell proliferation in clinical and research-grade media. We also show that Phx treatment enhances lentiviral-mediated gene expression across a wide range of multiplicity of infections (MOIs). We compared the ability of anti-GD-2 CAR-T cells expanded ex vivo in medium conditioned with either Phx or HS to clear tumor burden in a human xenograft model of neuroblastoma. We show that T cells expanded in Phx have superior engraftment and potency in vivo , as well as CAR-induced cytolytic activity in vitro . Metabolomic profiling revealed several factors unique to Phx that may have relevance for CAR-T cell preclinical discovery, process development, and manufacturing. In particular, we show that carnosine, a biogenic amine modestly enriched in Phx relative to HS, enhances lentiviral gene delivery in activated T cells. By limiting extracellular acidification, carnosine enhances the metabolic fitness of T cells, shifting their metabolic profile from an acidic, stressed state toward an oxidative, energetic state. These findings are very informative regarding potential derivatives to include in medium customized for gene delivery and overall potency for T cell adoptive immunotherapies.