Prodrug Nanomedicine Inhibits Chemotherapy-Induced Proliferative Burst by Altering the Deleterious Intercellular Communication

Nano-sensitizer with self-amplified drug release and hypoxia normalization properties potentiates efficient chemoradiotherapy of pancreatic cancer

The hypoxic nature of pancreatic cancer, one of the most lethal malignancies worldwide, significantly impedes the effectiveness of chemoradiotherapy. Although the development of oxygen carriers and hypoxic sensitizers has shown promise in overcoming tumor hypoxia. The heterogeneity of hypoxia-primarily caused by limited oxygen penetration-has posed challenges. In this study, we designed a hypoxia-responsive nano-sensitizer by co-loading tirapazamine (TPZ), KP372-1, and MK-2206 in a metronidazole-modified polymeric vesicle. This nano-sensitizer relies on efficient endogenous NAD(P)H quinone oxidoreductase 1-mediated redox cycling induced by KP372-1, continuously consuming periphery oxygen and achieving evenly distributed hypoxia. Consequently, the normalized tumor microenvironment facilitates the self-amplified release and activation of TPZ without requiring deep penetration. The activated TPZ and metronidazole further sensitize radiotherapy, significantly reducing the radiation dose needed for extensive cell damage. Additionally, the coloaded MK-2206 complements inhibition of therapeutic resistance caused by Akt activation, synergistically enhancing the hypoxic chemoradiotherapy. This successful hypoxia normalization strategy not only overcomes hypoxia resistance in pancreatic cancer but also provides a potential universal approach to sensitize hypoxic tumor chemoradiotherapy by reshaping the hypoxic distribution.

STING Membrane Prevents Post-Surgery Tissue Adhesion and Tumor Recurrence of Colorectal Cancer

Surgery is the standard treatment regimen for resectable colorectal cancer (CRC). However, it is very hard to completely remove all cancer cells in clinical practice, leading to the high recurrence rates of the disease. Moreover, the post-surgery tissue adhesion greatly prevents the possibility of reoperation, significantly limiting the long-term surviving of CRC patients. To overcome CRC recurrence and avoid the post-surgery tissue adhesion, this work develops a novel stimulator of interferon genes "STING" membrane based on the coaxial electrospinning technology and hyaluronic acid modification. A reactive oxygen species responsive prodrug of gambogic acid (GB) and a potent STING agonist (CDN) are coloaded in the core-shell structure of the membrane, which endows the loaded drug with sustained and sequential release patterns. The localized delivery of GB and CDN can selectively induce efficient immunogenic cell death of cancer cells and then evoke the systemic anticancer immunity by activating the Cyclic GMP-AMP (cGAMP) synthase/STING pathway. As-designed "STING" membrane not only safely prevents tumor recurrence through the synergistic chemoimmunotherapy but also efficiently avoids the post-surgery tissue adhesion, facilitating the clinical intervention of CRC.

Structural Modification Endows Small-Molecular SN38 Derivatives with Multifaceted Functions

As a camptothecin derivative, 7-ethyl-10-hydroxycamptothecin (SN38) combats cancer by inhibiting topoisomerase I. SN38 is one of the most active compounds among camptothecin derivatives. In addition, SN38 is also a theranostic reagent due to its intrinsic fluorescence. However, the poor water solubility, high systemic toxicity and limited action against drug resistance and metastasis of tumor cells of SN38 indicates that there is great space for the structural modification of SN38. From the perspective of chemical modification, this paper summarizes the progress of SN38 in improving solubility, increasing activity, reducing toxicity and possessing multifunction and analyzes the strategies of structure modification to provide a reference for drug development based on SN38.

Prodrug Nanosensitizer Overcomes the Radiation Resistance of Hypoxic Tumor

Clinical radiation therapy (RT) is often hindered by the low radiation energy absorption coefficient and the hypoxic features of tumor tissues. Among the tremendous efforts devoted to overcoming the barriers to efficient RT, the application of hypoxic radiosensitizers and cell-cycle-specific chemotherapeutics has shown great potential. However, their effectiveness is often compromised by their limited bioavailability, especially in the hypoxic region, which plays a major role in radioresistance. Herein, to simultaneously improve the delivery efficacy of both hypoxic radiosensitizer and cell-cycle-specific drug, a gambogic acid (GA) metronidazole (MN) prodrug (GM) was designed and synthesized based on GA, a naturally occurring chemotherapeutic and multiple pathway inhibitor, and MN, a typical hypoxic radiosensitizer. In combination with MN-containing block copolymers, the prodrug nanosensitizer (NS) of GM was obtained. Owing to the bioreduction of MN, the as-designed prodrug could be efficiently delivered to hypoxic cells and act on mitochondria to cause the accumulation of reactive oxygen species. The strong G₂/M phase arrest caused by the prodrug NS could further sensitize treated cells to external radiation under hypoxic conditions by increasing DNA damage and delaying DNA repair. After coadministration of the NS with a well-established tissue-penetrating peptide, efficient tumor accumulation, deep tumor penetration, and highly potent chemoradiotherapy could be achieved.

Deep-Penetrating Triple-Responsive Prodrug Nanosensitizer Actuates Efficient Chemoradiotherapy in Pancreatic Ductal Adenocarcinoma Models

Chemoradiotherapy (CRT) is the most accepted treatment for locally advanced pancreatic ductal adenocarcinoma (PDAC) and can significantly improve the R0 resection rate. However, there are few long-term survivors after CRT. Although some polymer nanoparticles have shown potential in alleviating the dose-limiting toxicity and assisting the chemotherapy of PDAC, there are few efficient nanosensitizers (NS) available for CRT of this malignancy, especially in the context of its hypoxic nature. Herein, based on the biological features of PDAC, a γ-glutamyl transpeptidase (GGT)/glutathione (GSH)/hypoxia triple-responsive prodrug NS to overcome the biological barrier and microenvironmental limitations confronted by CRT in PDAC is developed. Due to triple-responsiveness, deep tumor penetration, GSH/hypoxia-responsive drug release/activation, and hypoxia-induced chemoradio-sensitization can be simultaneously achieved with this NS. As a result, tumor shrinkage after CRT with this NS can be observed in both subcutaneous and orthotopic PDAC models, foreshadowing its potential in clinical neoadjuvant CRT.

Iron(III) Coordinated Theranostic Polyprodrug with Sequential Receptor-Mitochondria Dual Targeting and T1-Weighted Magnetic Resonance Imaging Potency for Effective and Precise Chemotherapy

The sequential cancer cell receptor and mitochondria dual-targeting single delivery agent deliver chemotherapeutic drug effectively and precisely at the targeted site has become a promising strategy to enhance the drug efficacy and suppressions of cancer cell drug resistance prominence. Herein, required specialty molecules like a chemotherapeutic drug [camptothecin (CPT)], mitochondriotropic segment (triphenyl phosphonium cation) receptor targeting ligand (biotin), and magnetic resonance imaging (MRI)-contrast agent (iron-complex) were tethered to the polyprodrug, CP TP PG BN Fe, using the ring-opening metathesis polymerization technique for potential chemotherapy and simultaneous MRI-based diagnosis. This amphiphilic polyprodrug spontaneously aggregated into nanospheres and exhibited remarkable T₁-weighted MRI proficiency. Detail in vitro cellular studies revealed unambiguous mitochondrial delivery of CPT, which eventually enhanced the chemotherapeutic efficacy of CP TP PG BN Fe. Therefore, MRI-tracking, receptor-mitochondria dual targeting, theranostic polyprodrug, and CP TP PG BN Fe opened the way for effective and precise chemotherapy, which would have the attractive potential for diagnosis and decisive dose determination in clinical implications.

Co-Delivery of Precisely Prescribed Multi-Prodrug Combination by an Engineered Nanocarrier enables Efficient Individualized Cancer Chemotherapy

The limited anticancer drug library and the frequent occurrence of drug resistance have driven monotherapy-based cancer therapy into a difficult situation. Considering the formidable process of new drug discovery, combination therapy using currently available drugs is a potential alternative. Nevertheless, the barrier between in vitro combination screening and precise in vivo delivery remains insurmountable in the current free-drug- or nanoparticle (NP)-based combination therapy, which substantially hinders the application of combination therapy. Herein, a novel, precise drug delivery strategy to realize efficient and individualized combination therapy is proposed. Nanomedicine (NM) is engineered using a microfluidics-based mixer by combining rationally designed polymeric prodrugs of three commercial chemotherapeutics and a cascade-responsive block copolymer; the NM possesses ratiometric drug loading and synchronized drug release. In addition to quantitative drug loading and precisely controlled drug combination, consistent nanoproperties of these NPs make their in vivo fate predictable. Consequently, tumor growth and metastasis can be effectively inhibited by precisely prescribed NPs derived from in vitro combination screening. This proof-of-concept study clearly reveals the feasibility of overcoming the current drug-library limitations through precise delivery of any predetermined drug combination, facilitating translational research of individualized combination therapy.

p53-Induced Autophagy Regulates Chemotherapy and Radiotherapy Resistance in Multidrug Resistance Cancer Cells

Background

Multidrug resistance (MDR), a major problem in oncology therapy, limits the effectiveness of anticancer drugs. Although p53 functions as a tumor suppressor, the associations between p53 status, autophagy, and MDR are complicated and conditional.

Method

 In this report, p53-null human ovarian cancer cell line SKOV3 and its MDR phenotype SKVCR and human leukemia cell line CEM and its MDR phenotype CEM-VLB) (p53 mutant cell line) were used.

Results

 Compared to parental SKOV3, the mRNA and protein levels of MAPLC3-II and Beclin1 were higher in SKVCR cells. The inhibition of autophagy by 3-MA significantly sensitized SKVCR to VCR. Conversely, in drug-resistant leukemic cells CEM-VLB, the expressions of Beclin1 and MAPLC3-II were lower than CEM. CEM and CEM-VLB cells were treated with VLB .01 or 0.5 μg/mL, respectively, and the expression of p53 and autophagy up-regulated after VLB (.01 μg/mL) treatment in CEM cells. The percentage of S-phase and G2/M phase cells up-regulated significantly by .01 μg/mL VLB in CEM, which may relate to the status of p53 of CEM cells. A combination of radiation with 3-MA significantly increased apoptosis in CEM-VLB cells.

Conclusion

 Our discovery found that p53 is an important regulator controlling the balance between autophagy and MDR, as a potential drug target for ovarian cancer and leukemia.

Multifunctional Plasmonic Core-Satellites Nanoprobe for Cancer Diagnosis and Therapy Based on a Cascade Reaction Induced by MicroRNA

Constructing multifunctional plasmonic core-satellites (CS) nanoassembly for clinical cancer diagnosis and therapy has gained vast attention. Herein, we reported a doxorubicin (Dox)-loaded CS nanoprobe for microRNA (miRNA) detection, targeting drug release, and therapy evaluation. The plasmonic CS nanoprobe was constructed with uniformly distributional 50 nm (core) and 13 nm (satellites) gold nanoparticles (AuNPs), which were functionally assembled with a specific sequence of DNA and peptides. Anticancer drug Dox was loaded by intercalating into the GC-rich double strands. In the presence of target miRNA (miRNA-21 used as model), the constructed CS nanostructure was disassembled, producing characteristic localized surface plasmon resonance (LSPR) signals and releasing Dox. With the increase of the miRNA-21 concentration ranging from 0.01 to 1000 fM, a distinct blue shift of scattering spectra peak occurred, along with obvious color change from orange to green under a dark-field microscope (DFM), which can be used to detect miRNA at single-particle level. Meanwhile, it released Dox-induced apoptosis. Caspase-3 involved in apoptosis was then activated to cleave the specific peptide substrate, releasing fluorophore FAM from AuNPs. As a result, caspase-3 was detected based on restored fluorescence intensity, which was used to evaluate the therapy effectiveness. In a word, the multifunctional plasmonic CS nanoprobe can be used not only to image cellular miRNA-21 to distinguish tumor cells from normal cells, but also to release drugs and monitor the apoptotic process in situ by confocal imaging.