Increased Active Tumor Targeting by An αvβ3-Targeting and Cell-Penetrating Bifunctional Peptide-Mediated Dendrimer-Based Conjugate

Gemcitabine-Phospholipid Complex Loaded Lipid Nanoparticles for Improving Drug Loading, Stability, and Efficacy against Pancreatic Cancer

This study aims to encapsulate gemcitabine (GEM) using a phospholipid complex (PLC) in lipid nanoparticles (NPs) to achieve several desirable outcomes, including high drug loading, uniform particle size, improved therapeutic efficacy, and reduced toxicities. The successful preparation of GEM-loaded lipid NPs (GEM-NPs) was accomplished using the emulsification-solidification method, following optimization through Box-Behnken design. The size of the GEM-NP was 138.5 ± 6.7 nm, with a low polydispersity index of 0.282 ± 0.078, as measured by a zetasizer and confirmed by transmission electron and atomic force microscopy. GEM-NPs demonstrated sustained release behavior, surpassing the performance of the free GEM and phospholipid complex. Moreover, GEM-NPs exhibited enhanced cytotoxicity, apoptosis, and cell uptake in Panc-2 and Mia PaCa cells compared to the free GEM. The in vivo pharmacokinetics revealed approximately 4-fold higher bioavailability of GEM-NPs in comparison with free GEM. Additionally, the pharmacodynamic evaluation conducted in a DMBA-induced pancreatic cancer model, involving histological examination, serum IL-6 level estimation, and expression of cleaved caspase-3, showed the potential of GEM-NPs in the management of pancreatic cancer. Consequently, the lipid NP-based approach developed in our investigation demonstrates high stability and uniformity and holds promise for enhancing the therapeutic outcomes of GEM.

Functional Materials for Subcellular Targeting Strategies in Cancer Therapy: Progress and Prospects

Neoadjuvant and adjuvant therapies have made significant progress in cancer treatment. However, tumor adjuvant therapy still faces challenges due to the intrinsic heterogeneity of cancer, genomic instability, and the formation of an immunosuppressive tumor microenvironment. Functional materials possess unique biological properties such as long circulation times, tumor-specific targeting, and immunomodulation. The combination of functional materials with natural substances and nanotechnology has led to the development of smart biomaterials with multiple functions, high biocompatibilities, and negligible immunogenicities, which can be used for precise cancer treatment. Recently, subcellular structure-targeting functional materials have received particular attention in various biomedical applications including the diagnosis, sensing, and imaging of tumors and drug delivery. Subcellular organelle-targeting materials can precisely accumulate therapeutic agents in organelles, considerably reduce the threshold dosages of therapeutic agents, and minimize drug-related side effects. This review provides a systematic and comprehensive overview of the research progress in subcellular organelle-targeted cancer therapy based on functional nanomaterials. Moreover, it explains the challenges and prospects of subcellular organelle-targeting functional materials in precision oncology. The review will serve as an excellent cutting-edge guide for researchers in the field of subcellular organelle-targeted cancer therapy.

An update on dual targeting strategy for cancer treatment

The key issue in the treatment of solid tumors is the lack of efficient strategies for the targeted delivery and accumulation of therapeutic cargoes in the tumor microenvironment (TME). Targeting approaches are designed for more efficient delivery of therapeutic agents to cancer cells while minimizing drug toxicity to normal cells and off-targeting effects, while maximizing the eradication of cancer cells. The highly complicated interrelationship between the physicochemical properties of nanoparticles, and the physiological and pathological barriers that are required to cross, dictates the need for the success of targeting strategies. Dual targeting is an approach that uses both purely biological strategies and physicochemical responsive smart delivery strategies to increase the accumulation of nanoparticles within the TME and improve targeting efficiency towards cancer cells. In both approaches, either one single ligand is used for targeting a single receptor on different cells, or two different ligands for targeting two different receptors on the same or different cells. Smart delivery strategies are able to respond to triggers that are typical of specific disease sites, such as pH, certain specific enzymes, or redox conditions. These strategies are expected to lead to more precise targeting and better accumulation of nano-therapeutics. This review describes the classification and principles of dual targeting approaches and critically reviews the efficiency of dual targeting strategies, and the rationale behind the choice of ligands. We focus on new approaches for smart drug delivery in which synthetic and/or biological moieties are attached to nanoparticles by TME-specific responsive linkers and advanced camouflaged nanoparticles.

Self-assembly of Peptide dendrimers and their bio-applications in theranostics

Nanotechnology has brought revolutionized advances in disease diagnosis and therapy. Self-assembled peptide dendrimers own novel physicochemical properties through the synergistic effects of the polypeptide chain, dendrimer and nano-structure, exhibiting great potential in theranostic. This review provides comprehensive insights into various peptide dendrimers for self-assembly. Their nanosize, morphology and composition are presented to understand self-assembly behaviors precisely. We further introduce the emerging theranostic applications based on specific imaging and efficient delivery recently.

Assessment of 177 Lu-labeled carboxyl-terminated polyamidoamine (PAMAM) dendrimer-RGD peptide conjugate

Structurally unique polyamidoamine (PAMAM) dendrimers implanted with targeting biological moiety along with complexed radiometal constitute a favorable nano-system for diagnosis and therapy of targeted tumor sites. In the present study, carboxyl functionalities of PAMAM- generation 4 dendrimer (PAMAM-G4-COOH) were conjugated with ε-amino group of lysine of cRGDfK peptide to impart integrin α_v β₃ targeting capability. Reaction of p-NH₂ -Bn-DOTA with PAMAM was accomplished via acid-amine coupling using EDC/NHS for ¹⁷⁷ Lu-complexation. ¹⁷⁷ Lu-labeled nano-system, ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK demonstrated receptor-mediated uptake in murine melanoma B16F10 cells during in vitro cell uptake studies. In vivo biodistribution studies demonstrated low tumor uptake and retention of ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK which may be attributed to rapid blood clearance. However, fast clearance from non-target organs resulted in higher target to background ratio. Tumor uptake of targeted nano-system, ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK was observed to be significantly (p < 0.05) higher in comparison to ¹⁷⁷ Lu-PAMAM-DOTA without the targeting peptide. Inhibition studies with unlabeled cRGDfK resulted in 60% reduction in tumor uptake of ¹⁷⁷ Lu-PAMAM-DOTA-cRGDfK, indicating specificity of the developed nano-system towards integrin α_v β₃ receptors.

Escaping the endosome: assessing cellular trafficking mechanisms of non-viral vehicles

Non-viral vehicles hold therapeutic promise in advancing the delivery of a variety of cargos in vitro and in vivo, including small molecule drugs, biologics, and especially nucleic acids. However, their efficacy at the cellular level is limited by several delivery barriers, with endolysosomal degradation being most significant. The entrapment of vehicles and their cargo in the acidified endosome prevents access to the cytosol, nucleus, and other subcellular compartments. Understanding the factors that contribute to uptake and intracellular trafficking, especially endosomal entrapment and release, is key to overcoming delivery obstacles within cells. In this review, we summarize and compare experimental techniques for assessing the extent of endosomal escape of a variety of non-viral vehicles and describe proposed escape mechanisms for different classes of lipid-, polymer-, and peptide-based delivery agents. Based on this evaluation, we present forward-looking strategies utilizing information gained from mechanistic studies to inform the rational design of efficient delivery vehicles.

Steroid 5α-Reductase Type I Induces Cell Viability and Migration via Nuclear Factor-κB/Vascular Endothelial Growth Factor Signaling Pathway in Colorectal Cancer

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Steroid 5α-reductase type I (SRD5A1), as an important part of the steroid metabolism, converts testosterone to dihydrotestosterone and regulates sex hormone levels, which accommodates tumor occurrence or development. However, the underlying molecular mechanism of SRD5A1 in CRC remains unclear. We compared SRD5A1 expression in CRC tissues with normal controls by immunohistochemistry and found that elevated SRD5A1 in CRC was relevant for poor patient prognosis. Furthermore, inducible downregulation of SRD5A1 by small hairpin RNA reduced cell viability, promoted cell cycle arrest, and induced cell apoptosis and cellular senescence of CRC cells, as well as attenuated cell migration ability. In the following experiments, we used dutasteride (an inhibitor of SRD5A1/2) to explore its inhibitory effect on the biological processes of CRC cells, as mentioned earlier. Further mechanism study demonstrated that the repression of SRD5A1 abolished the expression of p65 and vascular endothelial growth factor, suggesting that SRD5A1 might regulate cell viability and migration through nuclear factor-κB/vascular endothelial growth factor signaling pathway. Collectively, these findings implicate SRD5A1 acting as a novel biomarker for CRC diagnosis and prognosis and provide compelling evidence for the future evaluation of dutasteride as a promising candidate for CRC treatment.

Nanoparticles Modified with Cell-Penetrating Peptides: Conjugation Mechanisms, Physicochemical Properties, and Application in Cancer Diagnosis and Therapy

Based on their tunable physicochemical properties and the possibility of producing cell-specific platforms through surface modification with functional biomolecules, nanoparticles (NPs) represent highly promising tools for biomedical applications. To improve their potential under physiological conditions and to enhance their cellular uptake, combinations with cell-penetrating peptides (CPPs) represent a valuable strategy. CPPs are often cationic peptide sequences that are able to translocate across biological membranes and to carry attached cargos inside cells and have thus been recognized as versatile tools for drug delivery. Nevertheless, the conjugation of CPP to NP surfaces is dependent on many properties from both individual components, and further insight into this complex interplay is needed to allow for the fabrication of highly stable but functional vectors. Since CPPs per se are nonselective and enter nearly all cells likewise, additional decoration of NPs with homing devices, such as tumor-homing peptides, enables the design of multifunctional platforms for the targeted delivery of chemotherapeutic drugs. In this review, we have updated the recent advances in the field of CPP-NPs, focusing on synthesis strategies, elucidating the influence of different physicochemical properties, as well as their application in cancer research.

Designer Peptide and Protein Dendrimers: A Cross-Sectional Analysis

Dendrimers have attracted immense interest in science and technology due to their unique chemical structure that offers a myriad of opportunities for researchers. Dendritic design allows us to present peptides in a branched three-dimensional fashion that eventually leads to a globular shape, thus mimicking globular proteins. Peptide dendrimers, unlike other classes of dendrimers, have immense applications in biomedical research due to their biological origin. The diversity of potential building blocks and innumerable possibilities for design, along with the fact that the area is relatively underexplored, make peptide dendrimers sought-after candidates for various applications. This review summarizes the stepwise evolution of peptidic dendrimers along with their multifaceted applications in various fields. Further, the introduction of biomacromolecules such as proteins to a dendritic scaffold, resulting in complex macromolecules with discrete molecular weights, is an altogether new addition to the area of organic chemistry. The synthesis of highly complex and fully folded biomacromolecules on a dendritic scaffold requires expertise in synthetic organic chemistry and biology. Presently, there are only a handful of examples of protein dendrimers; we believe that these limited examples will fuel further research in this area.

Targeting Groups Employed in Selective Dendrons and Dendrimers

The design of compounds with directed action to a defined organ or tissue is a very promising approach, since it can decrease considerably the toxicity of the drug/bioactive compound. For this reason, this kind of strategy has been greatly important in the scientific community. Dendrimers, on the other hand, comprise extremely organized macromolecules with many peripheral functionalities, stepwise controlled synthesis, and defined size. These nanocomposites present several biological applications, demonstrating their efficiency to act in the pharmaceutical field. Considering that, the main purpose of this review was describing the potential of dendrons and dendrimers as drug targeting, applying different targeting groups. This application has been demonstrated through interesting examples from the literature considering the last ten years of publications.

Enhanced anti-hepatocarcinoma efficacy by GLUT1 targeting and cellular microenvironment-responsive PAMAM-camptothecin conjugate

The efficient targeting of drugs to tumor cell and subsequent rapid drug release remain primary challenges in the development of nanomedicines for cancer therapy. Here, we constructed a glucose transporter 1 (GLUT1)-targeting and tumor cell microenvironment-sensitive drug release Glucose–PEG–PAMAM-s-s–Camptothecin-Cy7 (GPCC) conjugate to tackle the dilemma. The conjugate was characterized by a small particle size, spherical shape, and glutathione (GSH)-sensitive drug release. In vitro tumor targeting was explored in monolayer (2D) and multilayer tumor spheroid (3D) HepG2 cancer cell models (GLUT1⁺). The cellular uptake of GPCC was higher than that in the control groups and that in normal L02 cells (GLUT1⁻), likely due to the conjugated glucose moiety. Moreover, the GPCC conjugate exhibited stronger cytotoxicity, higher S arrest and enhanced apoptosis and necrosis rate in HepG2 cells than control groups but not L02 cells. However, the cytotoxicity of GPCC was lower than that of free CPT, which could be explained by the slower release of CPT from the GPCC compared with free CPT. Additional in vivo tumor targeting experiments demonstrated the superior tumor-targeting ability of the GPCC conjugate, which significantly accumulated in tumor meanwhile minimize in normal tissues compared with control groups. The GPCC conjugate showed better pharmacokinetic properties, enabling a prolonged circulation time and increased camptothecin area under the curve (AUC). These features contributed to better therapeutic efficacy and lower toxicity in H22 hepatocarcinoma tumor-bearing mice. The GLUT1-targeting, GSH-sensitive GPCC conjugate provides an efficient, safe and economic approach for tumor cell targeted drug delivery.

cRGD functionalised nanocarriers for targeted delivery of bioactives

The integrins α_vβ₃ play a very imperative role in angiogenesis and are overexpressed in endothelial cells of the tumour. Recent years have witnessed huge exploration in the field of α_vβ₃ integrin-mediated bioactive targeting for treatment of cancer. In these studies, the cRGD peptide has been employed extensively owing to their binding capacity to the α_vβ₃ integrin. Principally, RGD-based approaches comprise of antagonist molecules of the RGD sequence, drug-RGD conjugates, and most importantly tethering of the nanocarrier surface with the RGD peptide as targeting ligand. Targeting tumour vasculature or cells via cRGD conjugated nanocarriers have emerged as a promising technique for delivering chemotherapeutic drugs and imaging agents for cancer theranostics. In this review, primary emphasis has been given on the application of cRGD-anchored nanocarriers for targeted delivery of drugs, imaging agents, etc. for tumour therapy.

A triple modality BSA-coated dendritic nanoplatform for NIR imaging, enhanced tumor penetration and anticancer therapy

Functional theranostic systems for drug delivery capable of concurrent near-infrared (NIR) fluorescence imaging, active tumor targeting and anticancer therapies are desired for concise cancer diagnosis and treatment. Dendrimers with controllable size and surface functionalities are good candidates for such platforms. However, integration of active targeting ligands and imaging agents separately on the surface or encapsulation of the imaging agents in the inner core of the dendrimers will result in a more complex composition or reduced drug loading efficiency. Herein, we reported a PAMAM-based theranostic system, with a simple integrin-specific imaging ligand prepared from two motifs. One motif is a NIR carbocyanine fluorescent dye (Cyp) for precise in vivo monitoring of the system and identification of tumor or cancer cells, and the other is a novel tumor-penetrating cyclic peptide (CRGDKGPDC, abbreviated iRGD). BSA was non-covalently bonded with Cyp to reduce NIR agent fluorescence-quenching aggregates and enhance imaging signals. The chemotherapy effect of these dendritic systems was achieved by encapsulating paclitaxel into the hydrophobic interior of the dendrimers. In vitro and in vivo targeting and penetrating studies revealed that a significantly high amount of the dendritic systems was endocytosed by HepG2 cells and enhanced accumulation and penetration at tumor sites. Our safety evaluation showed that masking of cationic-end groups of PAMAM to neutral or anionic groups has resulted in decreased or even zero-toxicity. The preliminary antitumor efficacy of the dendritic system was evaluated. In vitro and in vivo studies confirmed that paclitaxel-encapsulated functionalized PAMAM can efficiently kill HepG2 cancer cells. In conclusion, our functionalized theranostic dendritic system could be a promising nanocarrier to effectively deliver drugs to deep tumor regions for anticancer therapy.

Overcoming Multidrug Resistance through the GLUT1-Mediated and Enzyme-Triggered Mitochondrial Targeting Conjugate with Redox-Sensitive Paclitaxel Release

Multidrug resistance (MDR) is thought to be the major obstacle leading to the failure of paclitaxel (PTX) chemotherapy. To solve this problem, a glucose transporter-mediated and matrix metalloproteinase 2 (MMP2)-triggered mitochondrion-targeting conjugate [glucose-polyethylene glycol (PEG)-peptide-triphenylphosponium-polyamidoamine (PAMAM)-PTX] composed of a PAMAM dendrimer and enzymatic detachable glucose-PEG was constructed for mitochondrial delivery of PTX. The conjugate was characterized by a 30 nm sphere particle, MMP2-sensitive PEG outer layer detachment from PAMAM, and glutathione (GSH)-sensitive PTX release. It showed higher cellular uptake both in glucose transporter 1 (GLUT1) overexpressing MCF-7/MDR monolayer cell (2D) and multicellular tumor spheroids (3D). The subcellular location study showed that it could specifically accumulate in the mitochondria. Moreover, it exhibited higher cytotoxicity against MCF-7/MDR cells, which significantly reverse the MDR of MCF-7/MDR cells. The MDR reverse might be caused by reducing the ATP content through destroying the mitochondrial membrane as well as by down-regulating P-gp expression. In vivo imaging and tissue distribution indicated more conjugate accumulated in the tumor of the tumor-bearing mice model. Consequently, the conjugate showed better tumor inhibition rate and lower body weight loss, which demonstrated that it possessed high efficiency and low toxicity. This study provides glucose-mediated GLUT targeting, MMP2-responsive PEG detachment, triphenylphosponium-mediated mitochondria targeting, and a GSH-sensitive intracellular drug release conjugate that has the potential to be exploited for overcoming MDR of PTX.

Peptide dendrimers: drug/gene delivery and other approaches

Dendrimers are versatile hyperbranched molecules, which have deserved attention especially for their potential in many applications, including biological. Peptide dendrimers comprise interesting classes of dendrimers, and their use has been emphasized as a drug/bioactive compound delivery system, mostly in the antineoplastic area. The bioactive molecules can be covalently linked or entrapped inside the peptide derivative. Self-assembled nanocarriers are a recent trend in the design of potential delivery systems, and pH-sensitive carriers, one of their methods, have been designed to control their systems. In addition, the use of targeting peptides or other specific groups that direct the drug/bioactive compounds to specific organs is an important trend in the search for better drug delivery systems. Recent examples have been given in the literature, showing that gene delivery as another important peptide dendrimer application. It is worth emphasizing that some peptide dendrimers show activity per se, without bioactive compounds. Immune compounds and vaccines are presented herein, as well as uses of other peptide dendrimers are briefly discussed in this review, which encompasses around 10 years of work.

Multi-targeting peptides for gene carriers with high transfection efficiency

Non-viral gene carriers for gene therapy have been developed for many years.