Tumor-Oriented Telomerase-Terminated Nanoplatform as Versatile Strategy for Multidrug Resistance Reversal in Cancer Treatment

Nanoscale octopus guiding telomere entanglement: An innovative strategy for inducing apoptosis in cancer cells

Telomere length plays a crucial role in cellular aging and the risk of diseases. Unlike normal cells, cancer cells can extend their own survival by maintaining telomere stability through telomere maintenance mechanism. Therefore, regulating the lengths of telomeres have emerged as a promising approach for anti-cancer treatment. In this study, we introduce a nanoscale octopus-like structure designed to induce physical entangling of telomere, thereby efficiently triggering telomere dysfunction. The nanoscale octopus, composed of eight-armed PEG (8-arm-PEG), are functionalized with cell penetrating peptide (TAT) to facilitate nuclear entry and are covalently bound to N-Methyl Mesoporphyrin IX (NMM) to target G-quadruplexes (G4s) present in telomeres. The multi-armed configuration of the nanoscale octopus enables targeted binding to multiple G4s, physically disrupting and entangling numerous telomeres, thereby triggering telomere dysfunction. Both in vitro and in vivo experiments indicate that the nanoscale octopus significantly inhibits cancer cell proliferation, induces apoptosis through telomere entanglement, and ultimately suppresses tumor growth. This research offers a novel perspective for the development of innovative anti-cancer interventions and provides potential therapeutic options for targeting telomeres.

Acid-Responsive Polymer Micelles for Targeted Delivery and Bioorthogonal Activation of Prodrug through Ru Catalyst in Tumor Cells

Bioorthogonal reactions present a promising strategy for minimizing off-target toxicity in cancer chemotherapy, yet a dependable nanoplatform is urgently required. Here, we have fabricated an acid-responsive polymer micelle for the specific delivery and activation of the prodrug within tumor cells through Ru catalyst-mediated bioorthogonal reactions. The decomposition of micelles, triggered by the cleavage of the hydrazone bond in the acidic lysosomal environment, facilitated the concurrent release of Alloc-DOX and the Ru catalyst within the cells. Subsequently, the uncaging process of Alloc-DOX was demonstrated to be induced by the high levels of glutathione within tumor cells. Notably, the limited glutathione inside normal cells prevented the conversion of Alloc-DOX into active DOX, thereby minimizing the toxicity toward normal cells. In tumor-bearing mice, this nanoplatform exhibited enhanced efficacy in tumor suppression while minimizing off-target toxicity. Our study provides an innovative approach for in situ drug activation that combines safety and effectiveness in cancer chemotherapy.

Zeolitic Imidazolate Framework-8 (ZIF-8) as a Drug Delivery Vehicle for the Transport and Release of Telomerase Inhibitor BIBR 1532

Telomerase is constitutively overexpressed in the majority of human cancers and telomerase inhibition provides a promising broad-spectrum anticancer therapeutic strategy. BIBR 1532 is a well-known synthetic telomerase inhibitor that blocks the enzymatic activity of hTERT, the catalytic subunit of telomerase. However, water insolubility of BIBR 1532 leads to low cellular uptake and inadequate delivery and thus, limits its anti-tumor effects. Zeolitic imidazolate framework-8 (ZIF-8) is considered as an attractive drug delivery vehicle for improved transport, release and anti-tumor effects of BIBR 1532. Herein, ZIF-8 and BIBR 1532@ZIF-8 were synthesized, respectively, and the physicochemical characterizations confirmed the successful encapsulation of BIBR 1532 in ZIF-8 coupled with an improved stability of BIBR 1532. ZIF-8 could alter the permeability of lysosomal membrane probably by the imidazole ring-dependent protonation. Moreover, ZIF-8 encapsulation facilitated the cellular uptake and release of BIBR 1532 with more accumulation in the nucleus. BIBR 1532 encapsulation with ZIF-8 triggered a more obvious growth inhibition of cancer cells as compared with free BIBR 1532. A more potent inhibition on hTERT mRNA expression, aggravated G0/G1 arrest accompanied with an increased cellular senescence were detected in BIBR 1532@ZIF-8-treated cancer cells. Our work has provided preliminary information on improving the transport, release and efficacy of water-insoluble small molecule drugs by using ZIF-8 as a delivery vehicle.

Telomere therapy for chronic kidney disease

Chronic kidney disease (CKD) is estimated to affect almost 10% of individuals worldwide and is one of the leading causes of morbidity and mortality. Renal fibrosis, a central pathway in CKD progression (irrespective of etiology), is associated with shortened or dysfunctional telomeres in animal studies. Telomeres are specialized nucleoprotein structures located at the chromosome end that maintain genomic integrity. The mechanisms of associations between telomere length and CKD have not yet been fully elucidated, however, CKD patients with shorter telomere length may have decreased renal function and a higher mortality rate. A plethora of ongoing research has focused on possible therapeutic applications of telomeres with the overall goal to preserve telomere length as a therapy to treat CKD.

New Genetic Bomb Trigger: Design, Synthesis, Molecular Dynamics Simulation, and Biological Evaluation of Novel BIBR1532-Related Analogs Targeting Telomerase against Non-Small Cell Lung Cancer

Telomeres serve a critical function in cell replication and proliferation at every stage of the cell cycle. Telomerase is a ribonucleoprotein, responsible for maintaining the telomere length and chromosomal integrity of frequently dividing cells. Although it is silenced in most human somatic cells, telomere restoration occurs in cancer cells because of telomerase activation or alternative telomere lengthening. The telomerase enzyme is a universal anticancer target that is expressed in 85–95% of cancers. BIBR1532 is a selective non-nucleoside potent telomerase inhibitor that acts by direct noncompetitive inhibition. Relying on its structural features, three different series were designed, and 30 novel compounds were synthesized and biologically evaluated as telomerase inhibitors using a telomeric repeat amplification protocol (TRAP) assay. Target compounds 29a, 36b, and 39b reported the greatest inhibitory effect on telomerase enzyme with IC₅₀ values of 1.7, 0.3, and 2.0 μM, respectively, while BIBR1532 displayed IC₅₀ = 0.2 μM. Compounds 29a, 36b, and 39b were subsequently tested using a living-cell TRAP assay and were able to penetrate the cell membrane and inhibit telomerase inside living cancer cells. Compound 36b was tested for cytotoxicity against 60 cancer cell lines using the NCI (USA) procedure, and the % growth was minimally impacted, indicating telomerase enzyme selectivity. To investigate the interaction of compound 36b with the telomerase allosteric binding site, molecular docking and molecular dynamics simulations were used.

Recent Progress of Novel Nanotechnology Challenging the Multidrug Resistance of Cancer

Multidrug resistance (MDR) of tumors is one of the clinical direct reasons for chemotherapy failure. MDR directly leads to tumor recurrence and metastasis, with extremely grievous mortality. Engineering a novel nano-delivery system for the treatment of MDR tumors has become an important part of nanotechnology. Herein, this review will take those different mechanisms of MDR as the classification standards and systematically summarize the advances in nanotechnology targeting different mechanisms of MDR in recent years. However, it still needs to be seriously considered that there are still some thorny problems in the application of the nano-delivery system against MDR tumors, including the excessive utilization of carrier materials, low drug-loading capacity, relatively narrow targeting mechanism, and so on. It is hoped that through the continuous development of nanotechnology, nano-delivery systems with more universal uses and a simpler preparation process can be obtained, for achieving the goal of defeating cancer MDR and accelerating clinical transformation.

A tumor-activatable peptide supramolecular nanoplatform for the delivery of dual-gene targeted siRNAs for drug-resistant cancer treatment

Combinatorial short interference RNA (siRNA) technology for the silencing of multiple genes is expected to provide an effective therapeutic approach for cancer with complex genetic mutation and dysregulation. Herein we present a tumor-activatable supramolecular nanoplatform for the delivery of siRNAs to target telomerase and telomeres for paclitaxel-resistant non-small-cell lung cancer (A549/PTX) treatment. Two different sequences of siRNA are incorporated in a single nanoparticle, which is obtained by self-assembly from a peptide dendrimer. The siRNA stability is improved by the nanoparticle in the presence of serum compared to free siRNA, and these siRNAs are protected from RNA enzyme degradation. In the tumor extracellular acid environment, the PEG corona of the nanoparticle is removed to promote the internalization of siRNAs into tumor cells. The disulfide linkages between the nanoparticle and siRNAs are cleared in the reductive environment of the tumor cells, and the siRNAs are released in the cytoplasm. In vitro experiments show that the gene expression of hTERT and TRF2 at the mRNA and protein levels of A549/PTX tumor cells is down-regulated, which results in cooperative restraining proliferation and invasion of A549/PTX tumor cells. For the tumor cell-targeting function of the MUC1 aptamer and the EPR effect, sufficient tumor accumulation of nanoparticles was observed. Meanwhile, a shift of negative surface charge of nanoparticles to positive charge in the tumor extracellular microenvironment enhances deep penetration of siRNA-incorporating nanoparticles into tumor tissues. In vivo animal studies support that successful down-regulation of hTERT and TRF2 gene expression achieves effective inhibition of the growth and neovascularization of drug-resistant tumor cells. This work has provided a new avenue for drug-resistant cancer treatment by designing and synthesizing a tumor-activatable nanoplatform to achieve the delivery of dual-gene targeted combinatorial siRNAs.

Schiff-Linked PEGylated Doxorubicin Prodrug Forming pH-Responsive Nanoparticles With High Drug Loading and Effective Anticancer Therapy

Developing efficacious drug delivery systems for targeted cancer chemotherapy remains a major challenge. Here we demonstrated a kind of pH-responsive PEGylated doxorubicin (DOX) prodrug via the effective esterification and Schiff base reactions, which could self-assemble into the biodegradable micelles in aqueous solutions. Owing to low pH values inside the tumor cells, these PEG-Schiff-DOX nanoparticles exhibited high drug loading ability and pH-responsive drug release behavior within the tumor cells or tissues upon changes in physical and chemical environments, but they displayed good stability at physiological conditions for a long period. CCK-8 assay showed that these PEGylated DOX prodrugs had a similar cytotoxicity to the MCF-7 tumor cells as the free DOX drug. Moreover, this kind of nanoparticle could also encapsulate small DOX drugs with high drug loading, sufficient drug release and enhanced therapeutic effects toward MCF-7 cells, which will be benefited for developing more drug carriers with desirable functions for clinical anticancer therapy.