Polyethyleneimine-Based Drug Delivery Systems for Cancer Theranostics

Polymeric Nanoparticles for Drug Delivery

The recent emergence of nanomedicine has revolutionized the therapeutic landscape and necessitated the creation of more sophisticated drug delivery systems. Polymeric nanoparticles sit at the forefront of numerous promising drug delivery designs, due to their unmatched control over physiochemical properties such as size, shape, architecture, charge, and surface functionality. Furthermore, polymeric nanoparticles have the ability to navigate various biological barriers to precisely target specific sites within the body, encapsulate a diverse range of therapeutic cargo and efficiently release this cargo in response to internal and external stimuli. However, despite these remarkable advantages, the presence of polymeric nanoparticles in wider clinical application is minimal. This review will provide a comprehensive understanding of polymeric nanoparticles as drug delivery vehicles. The biological barriers affecting drug delivery will be outlined first, followed by a comprehensive description of the various nanoparticle designs and preparation methods, beginning with the polymers on which they are based. The review will meticulously explore the current performance of polymeric nanoparticles against a myriad of diseases including cancer, viral and bacterial infections, before finally evaluating the advantages and crucial challenges that will determine their wider clinical potential in the decades to come.

Cyclodextrin-conjugated low-molecular-weight polyethyleneimine as a macromolecular contrast agent for tumor-targeted magnetic resonance imaging

Macromolecular contrast agents (CAs) usually possess excellent contrast ability and tumor-targeting ability in comparison with small-molecule CAs, especially for early tumor detection. Herein, cyclodextrin-conjugated low-molecular-weight polyethyleneimine was synthesized as a macromolecular backbone. Afterward, a linear polymer with adamantane terminal and Gd chelates was synthesized, followed by conjugating with the backbone via host-guest interaction. Finally, folic acid was conjugated onto the as-prepared CAs through bioorthogonal chemistry, which endowed the CAs with the capability to accumulate into the tumor region. Compared to Magnevist (r1 = 4.25 mM-1 s-1) used in clinic, the PC/Ad-PEG2000-PLL(DTPA-Gd)-FA exhibited higher longitudinal relaxivity (r1 = 11.62 mM-1 s-1) with excellent biocompatibility. Furthermore, in vivo experiments demonstrated that PC/Ad-PEG2000-PLL(DTPA-Gd)-FA could effectively accumulate in the tumor region and produce a brighter image than that of Magnevist. The H&E staining and metabolic data further illustrated that this CA possessed excellent biocompatibility in vivo. Finally, these results above suggest that this macromolecular CA could be a potential candidate as a MRI CA for tumor-targeted diagnosis.

Understanding the mechanism of polyethyleneimine-mediated cell disintegration and protein extraction in E. coli: The role of floc network formation and PEI molecular weight

Cell disintegration and protein extraction are crucial steps in downstream process development for biopharmaceuticals produced in E. coli. In this study, we explored the extraction mechanism of polyethyleneimine (PEI) at the cellular level and characterized the floc network that is formed upon PEI addition by Focused Beam Reflectance Measurement and Dispersion Analyzer. PEI disintegrates the cells by detachment of the outer membrane allowing protein to diffuse into the interspace of the flocs. Protein release into the supernatant occurs by diffusion out of the floc network. We could show that the type and concentrations of PEIs with varying molecular weight determines the floc properties and thus the extraction efficiency. We could demonstrate why optimal conditions, using 70 kDa PEI at 0.25 g/g cell dry mass, lead to efficient extraction while at suboptimal conditions extraction is almost negligible. Our findings provide valuable insights into the relationship between floc properties and PEI-driven protein extraction, with potential applications in bioprocessing and biotechnology.

The crosstalk of CD8+ T cells and ferroptosis in cancer

Ferroptosis is an iron-dependent, novel form of programmed cell death characterized by lipid peroxidation and glutathione depletion and is widespread in a variety of diseases. CD8+ T cells are the most important effector cells of cytotoxic T cells, capable of specifically recognizing and killing cancer cells. Traditionally, CD8+ T cells are thought to induce cancer cell death mainly through perforin and granzyme, and Fas-L/Fas binding. In recent years, CD8+ T cell-derived IFN-γ was found to promote cancer cell ferroptosis by multiple mechanisms, including upregulation of IRF1 and IRF8, and downregulation of the system XC-, while cancer cells ferroptosis was shown to enhance the anti-tumor effects of CD8+ T cell by heating the tumor immune microenvironment through the exposure and release of tumor-associated specific antigens, which results in a positive feedback pathway. Unfortunately, the intra-tumoral CD8+ T cells are more sensitive to ferroptosis than cancer cells, which limits the application of ferroptosis inducers in cancer. In addition, CD8+ T cells are susceptible to being regulated by other immune cell ferroptosis in the TME, such as tumor-associated macrophages, dendritic cells, Treg, and bone marrow-derived immunosuppressive cells. Together, these factors build a complex network of CD8+ T cells and ferroptosis in cancer. Therefore, we aim to integrate relevant studies to reveal the potential mechanisms of crosstalk between CD8+ T cells and ferroptosis, and to summarize preclinical models in cancer therapy to find new therapeutic strategies in this review.

Multifunctional Fe3O4-PEI@HA nanoparticles in the ferroptosis treatment of hepatocellular carcinoma through modulating reactive oxygen species

Ferroptosis is a novel form of regulated cell death induced by iron-dependent lipid peroxidation imbalance. It has emerged as a promising antitumor therapeutic strategy in recent years. In this work, we successfully synthesized a complex magnetic nanocube Fe₃O₄ modified with PEI and HA by the thermal decomposition method. While loading a ferroptosis inducer RSL3 inhibited cancer cells through the ferroptosis signal transduction pathway. The drug delivery system could actively target tumor cells through an external magnetic field and HA-CD44 binding. Zeta potential analysis showed that Fe₃O₄-PEI@HA-RSL3 nanoparticles were more stable and uniformly dispersed in tumor acidic environment. Moreover, cellular experiments demonstrated that Fe₃O₄-PEI@HA-RSL3 nanoparticles could significantly inhibit the proliferation of hepatoma cells without a cytotoxic effect on normal hepatic cells. In addition, Fe₃O₄-PEI@HA-RSL3 played a vital role in ferroptosis by accelerating ROS production. The expression of ferroptosis-related genes Lactoferrin, FACL 4, GPX 4 and Ferritin was significantly suppressed with increasing treatment of Fe₃O₄-PEI@HA-RSL3 nanocubes. Therefore, this ferroptosis nanomaterial has great potential in Hepatocellular carcinoma (HCC) therapy.