Exploiting the acquired vulnerability of cisplatin-resistant tumors with a hypoxia-amplifying DNA repair-inhibiting (HYDRI) nanomedicine

Introducing urea into tirapazamine derivatives to enhance anticancer therapy

Tirapazamine (TPZ) has been approved for multiple clinical trials relying on its excellent anticancer potential. However, as a typical hypoxia-activated prodrug (HAP), TPZ did not exhibit survival advantages in Phase III clinical trials when used in combination therapy due to the insufficient hypoxia levels in patients' tumors. In this study, to improve the therapeutic effects of TPZ, we first introduced urea to synthesize a series of urea-containing derivatives of TPZ. All urea-containing TPZ derivatives showed increased hypoxic cytotoxicity (9.51-30.85-fold) compared with TPZ, while maintaining hypoxic selectivity. TPZP, one of these derivatives, showed 20-fold higher cytotoxicity than TPZ while maintaining a similar hypoxic cytotoxicity ratio. To highly efficiently deliver TPZP to the tumors and reduce its side effects on healthy tissues, we further prepared TPZP into a nanodrug with fibrin-targeting ability: FT11-TPZP-NPs. CA4-NPs, a vascular disrupting agent, was used to increase the fibrin level within tumors and exacerbate tumor hypoxia. By being combined with CA4-NPs, FT11-TPZP-NPs can accumulate in the hypoxia-aggravated tumors and activate sufficiently to kill tumor cells. After a single-dose treatment, FT11-TPZP-NPs + CA4-NPs showed a high inhibition rate of 98.1% against CT26 tumor models with an initial volume of ∼480 mm3 and four out of six tumors were completely eliminated; it thereby exerted a significant antitumor effect. This study provides a new strategy for improving the therapeutic effect of TPZ and other HAPs in anticancer therapy.

Nanodelivery Systems as a Novel Strategy to Overcome Treatment Failure of Cancer

Despite the tremendous progress in cancer treatment in recent decades, cancers often become resistant due to multiple mechanisms, such as intrinsic or acquired multidrug resistance, which leads to unsatisfactory treatment effects or accompanying metastasis and recurrence, ultimately to treatment failure. With a deeper understanding of the molecular mechanisms of tumors, researchers have realized that treatment designs targeting tumor resistance mechanisms would be a promising strategy to break the therapeutic deadlock. Nanodelivery systems have excellent physicochemical properties, including highly efficient tissue-specific delivery, substantial specific surface area, and controllable surface chemistry, which endow nanodelivery systems with capabilities such as precise targeting, deep penetration, responsive drug release, multidrug codelivery, and multimodal synergy, which are currently widely used in biomedical researches and bring a new dawn for overcoming cancer resistance. Based on the mechanisms of tumor therapeutic resistance, this review summarizes the research progress of nanodelivery systems for overcoming tumor resistance to improve therapeutic efficacy in recent years and offers prospects and challenges of the application of nanodelivery systems for overcoming cancer resistance.

Deep Insight of Design, Mechanism, and Cancer Theranostic Strategy of Nanozymes

Since the discovery of enzyme-like activity of Fe3O4 nanoparticles in 2007, nanozymes are becoming the promising substitutes for natural enzymes due to their advantages of high catalytic activity, low cost, mild reaction conditions, good stability, and suitable for large-scale production. Recently, with the cross fusion of nanomedicine and nanocatalysis, nanozyme-based theranostic strategies attract great attention, since the enzymatic reactions can be triggered in the tumor microenvironment to achieve good curative effect with substrate specificity and low side effects. Thus, various nanozymes have been developed and used for tumor therapy. In this review, more than 270 research articles are discussed systematically to present progress in the past five years. First, the discovery and development of nanozymes are summarized. Second, classification and catalytic mechanism of nanozymes are discussed. Third, activity prediction and rational design of nanozymes are focused by highlighting the methods of density functional theory, machine learning, biomimetic and chemical design. Then, synergistic theranostic strategy of nanozymes are introduced. Finally, current challenges and future prospects of nanozymes used for tumor theranostic are outlined, including selectivity, biosafety, repeatability and stability, in-depth catalytic mechanism, predicting and evaluating activities.

Canagliflozin reduces chemoresistance in hepatocellular carcinoma through PKM2-c-Myc complex-mediated glutamine starvation

Cisplatin (CPT) is one of the standard treatments for hepatocellular carcinoma (HCC). However, its use is limits as a monotherapy due to drug resistance, and the underlying mechanism remains unclear. To solve this problem, we tried using canagliflozin (CANA), a clinical drug for diabetes, to reduce chemoresistance to CPT, and the result showed that CANA could vigorously inhibit cell proliferation and migration independent of the original target SGLT2. Mechanistically, CANA reduced aerobic glycolysis in HCC by targeting PKM2. The downregulated PKM2 directly bound to the transcription factor c-Myc in the cytoplasm to form a complex, which upregulated the level of phosphorylated c-Myc Thr58 and promoted the ubiquitination and degradation of c-Myc. Decreased c-Myc reduced the expression of GLS1, a key enzyme in glutamine metabolism, leading to impaired glutamine utilization. Finally, intracellular glutamine starvation induced ferroptosis and sensitized HCC to CPT. In conclusion, our study showed that CANA re-sensitized HCC to CPT by inducing ferroptosis through dual effects on glycolysis and glutamine metabolism. This is a novel mechanism to increase chemosensitivity, which may provide compatible chemotherapy drugs for HCC.

Emerging platinum(IV) prodrug nanotherapeutics: A new epoch for platinum-based cancer therapy

Owing to the unique DNA damaging cytotoxicity, platinum (Pt)-based chemotherapy has long been the first-line choice for clinical oncology. Unfortunately, Pt drugs are restricted by the severe dose-dependent toxicity and drug resistance. Correspondingly, Pt(IV) prodrugs are developed with the aim to improve the antitumor performance of Pt drugs. However, as "free" molecules, Pt(IV) prodrugs are still subject to unsatisfactory in vivo destiny and antitumor efficacy. Recently, Pt(IV) prodrug nanotherapeutics, inheriting both the merits of Pt(IV) prodrugs and nanotherapeutics, have emerged and demonstrated the promise to address the underexploited dilemma of Pt-based cancer therapy. Herein, we summarize the latest fronts of emerging Pt(IV) prodrug nanotherapeutics. First, the basic outlines of Pt(IV) prodrug nanotherapeutics are overviewed. Afterwards, how versatile Pt(IV) prodrug nanotherapeutics overcome the multiple biological barriers of antitumor drug delivery is introduced in detail. Moreover, advanced combination therapies based on multimodal Pt(IV) prodrug nanotherapeutics are discussed with special emphasis on the synergistic mechanisms. Finally, prospects and challenges of Pt(IV) prodrug nanotherapeutics for future clinical translation are spotlighted.

Self-Assembled Carrier-Free Nanodrugs for Starvation Therapy-Amplified Photodynamic Therapy of Cancer

Traditional starvation treatment strategies, which involve glucose oxidase and drug-induced thrombi, often suffer from aggravated tumor hypoxia and have failed to improve antitumor efficacy in combination with oxygen-dependent photodynamic therapy (PDT). Herein, glucose transporter 1 inhibitor genistein (Gen) and photosensitizer chlorin e6 (Ce6) are integrated to construct carrier-free self-assembled nanoparticles defined as GC NPs, for starvation therapy-amplified PDT of tumor. GC NPs with regular morphology and stability are screened out by component adjustment, while the function of each component is preserved. On the one hand, Gen released from GC NPs can cut off tumor glucose uptake by inhibiting the glucose transporter 1 to restrict tumor growth, achieving starvation therapy. On the other hand, they are able to decrease the amount of oxygen consumed by tumor respiration and amplify the therapeutic effect of PDT. In vitro and in vivo experiments verify the excellent synergistic antitumor therapeutic efficacy of GC NPs without any apparent toxicity. Moreover, fluorescence and photoacoustic imaging provide guidance for in vivo PDT, demonstrating the excellent tumor enrichment efficiency of GC NPs. It is believed that this starvation therapy-amplified PDT strategy by carrier-free self-assembled GC NPs holds promising clinical prospects.

A Bioresponsive Diselenide-functionalized Hydrogel with Cascade Catalytic Activities for Enhanced Local Starvation- and Hypoxia-Activated Melanoma Therapy

Glutathione (GSH) consumption-enhanced cancer therapies represent important potential cancer treatment strategies. Herein, we developed a new multifunctional diselenide-crosslinked hydrogel with glutathione peroxidase (GPx)-like catalytic activity for GSH depletion-enhanced glucose oxidase (GOx)-mediated tumor starvation and hypoxia-activated chemotherapy. By increasing acid and H₂O₂ during GOx-induced tumor starvation, the degradation of the multiresponsive scaffold could be promoted, which led to accelerated release of the loaded drugs. Meanwhile, the overproduced H₂O₂ led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H₂O₂ and subsequent multimodal cancer treatment. Following the GOx-induced amplification of hypoxia, tirapazamine (TPZ) was transformed into the highly toxic benzotriazinyl radical (BTZ·), exhibiting enhanced antitumor activity. This GSH depletion-augmented cancer treatment strategy effectively boosted GOx-mediated tumor starvation and activated the hypoxia drug, leading to significantly enhanced local anticancer efficacy. STATEMENT OF SIGNIFICANCE: There has been a growing interest in depleting intracellular GSH as a potential strategy for improving ROS-based cancer therapy. Herein, a bioresponsive diselenide-functionalized dextran-based hydrogel with GPx-like catalytic activity was developed for GSH consumption-enhanced local starvation- and hypoxia-activated melanoma therapy. Results showed that the overproduced H₂O₂ led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H₂O₂ and subsequent multimodal cancer treatment.

Acid-Responsive Macroporous Silica Nanoparticles for Bcl-2-Functional-Converting Peptide Release and Synergism with Celastrol for Enhanced Therapy against Resistant Cancer

Combination of chemotherapeutics with polypeptide/protein drugs has been demonstrated to be an effective approach for treatment against cancer multidrug resistance. However, due to the low biostability and weak cell penetrating ability of biomacromolecules, intracellular delivery and release of biomacromolecules in a spatiotemporally controllable manner in target sites in vivo face great challenges, and synergistic effects will not be achieved as expected just by simple drug combination. Here, we conceived an inspired strategy to combat the drug-resistant tumors by fabricating multiarm PEG-gated large pore-sized mesoporous silica nanoparticles for the Bcl-2-functional-converting peptide (denoted as N9@M-CA∼8P) payload and controlled release and realizing synergistic effects with celastrol integration at a low dosage as a curative sensitizer. Our results demonstrated that the N9 peptide could be pH-responsively released from the macropores of the M-CA∼8P nanosystem both in simulated physiological environments and in cancer cells and at tumor sites. Biosafe and enhanced therapeutic outcomes (90% tumor inhibition) were obtained by combination of the N9@M-CA∼8P nanosystem with celastrol coordinatively inducing mitochondrion-mediated cell apoptosis in resistant cancer cell lines and in the corresponding xenografted mice models. Overall, this study provides convincing evidence for effective and safe resistant cancer treatment through a stimulus-responsive biomacromolecule nanosystem combined with a low dosage of a natural compound.

In Situ STING-Activating Nanovaccination with TIGIT Blockade for Enhanced Immunotherapy of Anti-PD-1-Resistant Tumors

Immunotherapies comprising programmed cell death protein 1/PD ligand 1 (PD-1/PD-L1) immune checkpoint inhibitors are effective cancer treatments. However, the low response rate and immunoresistance resulting from alternative immune checkpoint upregulation and inefficient immune stimulation by T cells are problematic. The present report describes a biomimetic nanoplatform that simultaneously blocks the alternative T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) checkpoint and activates the stimulator of interferon genes (STING) signaling pathway in situ for enhanced antitumor immunity. The nanoplatform is engineered by fusing a red blood cell membrane with glutathione-responsive liposome-encapsulated cascade-activating chemoagents (β-lapachone and tirapazamine), and anchoring them with a detachable TIGIT block peptide (named as RTLT). In the tumor environment, the peptide is spatiotemporally released to reverse T-cell exhaustion and restore antitumor immunity. The cascade activation of chemotherapeutic agents causes DNA damage and inhibits the repair of double-stranded DNA, which induces robust in situ STING activation for an efficient immune response. The RTLT inhibits anti-PD-1-resistant tumor growth, and prevents tumor metastasis and recurrence in vivo by inducing antigen-specific immune memory. This biomimetic nanoplatform thus provides a promising strategy for in situ cancer vaccination.

Long noncoding RNA SNHG15: A promising target in human cancers

As oncogenes or tumor suppressor genes, lncRNAs played an important role in tumorigenesis and the progression of human cancers. The lncRNA SNHG15 has recently been revealed to be dysregulated in malignant tumors, suggesting the aberrant expression of which contributes to clinical features and regulates various oncogenic processes. We have selected extensive literature focused on SNHG15 from electronic databases, including studies relevant to its clinical significance and the critical events in cancer-related processes such as cell proliferation, apoptosis, autophagy, metastasis, and drug resistance. This review summarized the current understanding of SNHG15 in cancer, mainly focusing on the pathological features, known biological functions, and underlying molecular mechanisms. Furthermore, SNHG15 has been well-documented to be an effective diagnostic and prognostic marker for tumors, offering novel therapeutic interventions in specific subsets of cancer cells.

A Clinically Translatable Ternary Platinum(IV) Prodrug for Synergistically Reversing Drug Resistance

Scalable production of a clinically translatable formulation with enhanced therapeutic efficacy against cisplatin-resistant tumors without the use of any clinically unapproved reagents and additional manipulation remains a challenge. For this purpose, we report herein the construction of TPP-Pt-acetal-CA based on all commercially available, clinically approved reagents consisting of a cinnamaldehyde (CA) unit for reactive oxygen species generation, a mitochondrially targeted triphenylphosphonium (TPP)-modified Pt(IV) moiety for mitochondrial dysfunction, and an intracellular acidic pH-cleavable acetal link between these two moieties. The resulting self-assembled, stabilized TPP-Pt-acetal-CA nanoparticles mediated an IC₅₀ value approximately 6-fold lower than that of cisplatin in A549/DDP cells and a tumor weight reduction 3.6-fold greater than that of cisplatin in A549/DDP tumor-bearing BALB/c mice with insignificant systematic toxicity due to the synergistic mitochondrial dysfunction and markedly amplified oxidative stress. Therefore, this study presents the first example of a clinically translatable Pt(IV) prodrug with enhanced efficiency for synergistically reversing drug resistance.

Highly potent Platinum(IV) complexes with multiple-bond ligands targeting mitochondria to overcome cisplatin resistance

The efficacy and resistance of cisplatin-based compounds are very intractable problems at present. This study reports a series of platinum(IV) compounds containing multiple-bond ligands, which exhibited better tumor cell inhibitory activity and antiproliferative and anti-metastasis activities than cisplatin. The meta-substituted compounds 2 and 5 were particularly excellent. Further research showed that compounds 2 and 5 possessed appropriate reduction potential and performed significantly better than cisplatin in cellular uptake, reactive oxygen species response, the up-regulation of apoptosis and DNA lesion-related genes, and drug-resistant cell activity. The title compounds exhibited better antitumor potential and fewer side effects than cisplatin in vivo. Multiple-bond ligands were introduced into cisplatin to form the title compounds in this study, which not only enhanced their absorption and overcame drug resistance but also demonstrated the potential to target mitochondria and inhibit the detoxification of tumor cells.

Multistage O2-producing liposome for MRI-guided synergistic chemodynamic/chemotherapy to reverse cancer multidrug resistance

Reduced drug uptake and elevated drug efflux are two major mechanisms in cancer multidrug resistance (MDR). In the present study, a new multistage O₂-producing liposome with NAG/R8-dual-ligand and stimuli-responsive dePEGylation was developed to address the abovementioned issues simultaneously. The designed C-NAG-R8-PTXL/MnO₂-lip could also achieve magnetic resonance imaging (MRI)-guided synergistic chemodynamic/chemotherapy (CDT/CT). In vitro and in vivo studies showed that C-NAG-R8-PTXL/MnO₂-lip enhanced circulation time by PEG and targeted the tumor site. After tumor accumulation, endogenous l-cysteine was administered, and the PEG-attached disulfide bond was broken, resulting in the dissociation of PEG shells. The previously hidden positively charged R8 by different lengths of PEG chains was exposed and mediated efficient internalization. In addition, the oxygen (O₂) generated by C-NAG-R8-PTXL/MnO₂-lip relieved the hypoxic environment within the tumor, thus reducing the efflux of chemotherapeutic drug. O₂ was able to burst liposomes and triggered the release of PTXL. The toxic hydroxyl radical (·OH), which was produced by H₂O₂ and Mn²⁺, strengthened CDT/CT. C-NAG-R8-PTXL/MnO₂-lip was also used as MRI contrast agent, which blazed the trail to rationally design theranostic agents for tumor imaging.

Bone-Targeted Dual Functional Lipid-coated Drug Delivery System for Osteosarcoma Therapy

PURPOSE OR OBJECTIVE

Osteosarcoma is well-known for its high incidence in children and adolescents and long-term bone pain, which seriously reduces the life quality of patients. Cisplatin (CDDP), as the first-line anti-osteosarcoma drug, has been used in many anticancer treatments. At the same time, the serious side effects of platinum (Pt) drugs have also attracted widespread attention. To accurately deliver Pt drugs to the lesion site and realize controlled release of Pt drugs, certain modified delivery systems have been extensively studied.

METHODS

Among them, liposomes have been approved for clinical cancer treatment due to their highly biocompatibility and superior modifiability. Here, we developed a bone-targeted dual functional lipid-coated drug delivery system, lipid-coated CDDP alendronate nanoparticles (LCA NPs) to target the bone and precisely deliver the drugs to the tumor site. Cell toxicity, apoptosis and cellular uptake were detected to evaluate the anticancer effect for LCA NPs. Furthermore, transwell assay and wound healing assay were conducted to estimate the osteosarcoma cell migration and invasion. Hemolysis assay was utilized to assess the biocapitibility of the kind of NPs.

RESULTS

With the aim of bone-targeted unit alendronate (ALD), LCA NPs serve as a rich bone homing Pt delivery system to exert efficient anticancer effects and synergistically reduce bone resorption and bone loss potentially.

CONCLUSIONS

By providing a highly biocompatible platform for osteosarcoma therapy, LCA NPs may help to significantly enhance the anticancer effect of Pt and greatly reduce the systemic toxicity and side effects of Pt towards osteosarcoma.

A dual-response drug delivery system with X-ray and ROS to boost the anti-tumor efficiency of TPZ via enhancement of tumor hypoxia levels

The selective anti-tumor activity and less toxic nature of hypoxia-activated prodrugs including tirapazamine (TPZ) are harbored by hypoxia levels in tumors, the inadequacy of which leads to failure in clinical trials. Thus, the development of effective clinical applications of TPZ requires advanced strategies to intensify hypoxia levels in tumors effectively and safely. In this study, we designed and fabricated a paclitaxel (PTX)-loaded dual-response delivery system with a low dose (e.g., 2 Gy) of X-ray and reactive oxygen species on the basis of diselenide block copolymers. Upon the external X-ray stimulus, the system accurately released encapsulated PTX at tumor sites and remarkably improved tumor hypoxia levels by causing severe damage to tumor blood vessels. Subsequently, these enhanced tumor hypoxia levels effectively activated the reduction of TPZ into benzotriazinyl free radicals, which significantly improved the antitumor efficacy of our system against 4T1 breast cancer cells with an initial tumor volume of 500 mm³. Moreover, the dual-stimulus coordinated and controlled release of PTX was found to largely avoid the off-target effects of PTX on normal cells while exhibiting very limited side effects in experimental mice. The current novel strategy for regulating tumor hypoxia levels offers an effective and safe way to activate TPZ for the treatment of large solid tumors.

A nuclease-mimetic platinum nanozyme induces concurrent DNA platination and oxidative cleavage to overcome cancer drug resistance

Platinum (Pt) resistance in cancer almost inevitably occurs during clinical Pt-based chemotherapy. The spontaneous nucleotide-excision repair of cancer cells is a representative process that leads to Pt resistance, which involves the local DNA bending to facilitate the recruitment of nucleotide-excision repair proteins and subsequent elimination of Pt-DNA adducts. By exploiting the structural vulnerability of this process, we herein report a nuclease-mimetic Pt nanozyme that can target cancer cell nuclei and induce concurrent DNA platination and oxidative cleavage to overcome Pt drug resistance. We show that the Pt nanozyme, unlike cisplatin and conventional Pt nanoparticles, specifically induces the nanozyme-catalyzed cleavage of the formed Pt-DNA adducts by generating in situ reactive oxygen species, which impairs the damage recognition factors-induced DNA bending prerequisite for nucleotide-excision repair. The recruitment of downstream effectors of nucleotide-excision repair to DNA lesion sites, including xeroderma pigmentosum groups A and F, is disrupted by the Pt nanozyme in cisplatin-resistant cancer cells, allowing excessive accumulation of the Pt-DNA adducts for highly efficient cancer therapy. Our study highlights the potential benefits of applying enzymatic activities to the use of the Pt nanomedicines, providing a paradigm shift in DNA damaging chemotherapy.

Perspectives of metal-organic framework nanosystem to overcome tumor drug resistance

Cancer is one of the most harmful diseases in the world, which causes huge numbers of deaths every year. Many drugs have been developed to treat tumors. However, drug resistance usually develops after a period of time, which greatly weakens the therapeutic effect. Tumor drug resistance is characterized by blocking the action of anticancer drugs, resisting apoptosis and DNA repair, and evading immune recognition. To tackle tumor drug resistance, many engineered drug delivery systems (DDS) have been developed. Metal-organic frameworks (MOFs) are one kind of emerging and promising nanocarriers for DDS with high surface area and abundant active sites that make the functionalization simpler and more efficient. These features enable MOFs to achieve advantages easily towards other materials. In this review, we highlight the main mechanisms of tumor drug resistance and the characteristics of MOFs. The applications and opportunities of MOF-based DDS to overcome tumor drug resistance are also discussed, shedding light on the future development of MOFs to address tumor drug resistance.

Development and validation of a pyradiomics signature to predict initial treatment response and prognosis during transarterial chemoembolization in hepatocellular carcinoma

We aimed to develop and validate a pyradiomics model for preoperative prediction of initial treatment response to transarterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC). To this end, computed tomography (CT) images were acquired from multi-centers. Numerous pyradiomics features were extracted and machine learning approach was used to build a model for predicting initial response of TACE treatment. The predictive accuracy, overall survival (OS), and progression-free survival (PFS) were analyzed. Gene Set Enrichment Analysis (GSEA) was further used to explore signaling pathways in The Cancer Genome Atlas (TCGA)-HCC cohort. Overall, 24 of the 1,209 pyradiomic features were selected using the least absolute shrinkage and selection operator (LASSO) algorithm. The pyradiomics signature showed high predictive accuracy across the discovery set (AUC: 0.917, 95% confidence interval [CI]: 86.93-96.39), validation set 1 (AUC: 0.902, 95% CI: 84.81-95.59), and validation set 2 (AUC: 0.911; 95% CI: 83.26-98.98). Based on the classification of pyradiomics model, we found that a group with high values base on pyramidomics score showed good PFS and OS (both P<0.001) and was negatively correlated with glycolysis pathway. The proposed pyradiomics signature could accurately predict initial treatment response and prognosis, which may be helpful for clinicians to better screen patients who are likely to benefit from TACE.

Enhancing Tumor Therapy of Fe(III)-Shikonin Supramolecular Nanomedicine via Triple Ferroptosis Amplification

Ferroptosis has been considered as a promising pathway to overcome apoptosis-induced tumor chemoresistance. However, the antitumor efficacy of ferroptosis-inducing agents is still limited because of the complexity and diversity of tumor microenvironments. Herein, we demonstrate a triple ferroptosis amplification strategy for tumor therapy by associating iron-based nanocarriers, ferroptosis molecular drugs, and H₂O₂-producing enzymes. Fe(III)-Shikonin (FeShik) metal-polyphenol-coordinated networks are employed to load a ferroptosis inducer of sorafenib (SRF) inside and glucose oxidase (GOx) outside, thus producing SRF@FeShik-GOx supramolecular nanomedicines (SNs). After delivering into glutathione (GSH)-overexpressed tumor cells, FeShik will disassemble and release Fe²⁺ to induce cell death via ferroptosis. At the same time, GOx executes its catalytic activity to produce an acid environment and plenty of H₂O₂ for stimulating ^•OH generation via the Fenton reaction. Moreover, SRF will suppress the biosynthesis of GSH by inhibiting system Xc^-, further deactivating the enzymatic activity of glutathione peroxidase 4 (GPX4). Up-regulation of the oxidative stress level and down-regulation of GPX4 expression can dramatically accelerate the accumulation of lethal lipid peroxides, leading to ferroptosis amplification of tumor cells. The current strategy that utilizes ferroptosis-inducing agents as both nanocarriers and cargoes provides a pathway to enhance the efficacy of ferroptosis-based tumor therapy.

Brain Co-Delivery of Temozolomide and Cisplatin for Combinatorial Glioblastoma Chemotherapy

Glioblastoma (GBM) is an intractable malignancy with high recurrence and mortality. Combinatorial therapy based on temozolomide (TMZ) and cisplatin (CDDP) shows promising potential for GBM therapy in clinical trials. However, significant challenges include limited blood-brain-barrier (BBB) penetration, poor targeting of GBM tissue/cells, and systemic side effects, which hinder its efficacy in GBM therapy. To surmount these challenges, new GBM-cell membrane camouflaged and pH-sensitive biomimetic nanoparticles (MNPs) inspired by the fact that cancer cells readily pass the BBB and localize with homologous cells, are developed. This study's results show that MNPs can efficiently co-load TMZ and CDDP, transport these across the BBB to specifically target GBM. Incorporation of pH-sensitive polymer then allows for controlled release of drug cargos at GBM sites for combination drug therapy. Mice bearing orthotopic U87MG or drug-resistant U251^R GBM tumor and treated with MNPs@TMZ+CDDP show a potent anti-GBM effect, greatly extending the survival time relative to mice receiving single-drug loaded nanoparticles. No obvious side effects are apparent in histological analyses or blood routine studies. Considering these results, the study's new nanoparticle formulation overcomes multiple challenges currently limiting the efficacy of combined TMZ and CDDP GBM drug therapy and appears to be a promising strategy for future GBM combinatorial chemotherapy.

Thermo- and Light-Responsive Polymer-Coated Magnetic Nanoparticles as Potential Drug Carriers

A series of thermo- and light-responsive copolymers of poly (N-isopropylacrylamide) (PNIPAM) and 6-[4-(4-methoxy phenyl azo)-phenoxyl-hexyl methacrylate) (AzoMA) (PNIPAM-b-PAzoMA) were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization. The resulting copolymers had a narrow molecular weight distribution range of 1.06–1.24, in which Mn changed regularly with the monomer concentration. Subsequently, the diblock copolymers were successfully modified on the surface of iron oxide nanoparticles through the interaction between the chemical bonds to prepare Fe3O4@(PNIPAM-b-PAzoMA) nanoparticles. The size of fabricated nanoparticles with excellent thermo-sensitivity and photo-sensitivity was controlled at about 40–50 nm. Cell viability assays suggested that the nanoparticles showed no significant cytotoxicity and potential drug delivery in the tumor microenvironment.

DNA damage and metabolic mechanisms of cancer drug resistance

Cancer drug resistance is one of the main barriers to overcome to ensure durable treatment responses. While many pivotal advances have been made in first combination therapies, then targeted therapies, and now broadening out to immunomodulatory drugs or metabolic targeting compounds, drug resistance is still ultimately universally fatal. In this brief review, we will discuss different strategies that have been used to fight drug resistance from synthetic lethality to tumor microenvironment modulation, focusing on the DNA damage response and tumor metabolism both within tumor cells and their surrounding microenvironment. In this way, with a better understanding of both targetable mutations in combination with the metabolism, smarter drugs may be designed to combat cancer drug resistance.

Targeted nanomedicine in cisplatin-based cancer therapeutics

Since its license in 1978, cisplatin has proved to be one of the most successful chemotherapeutic agents in the world. However, two acute challenges facing cisplatin, resistance and toxicity, have resulted in a bottleneck of clinical application. Targeted nanomedicine shows great promise in delivering cisplatin for maximizing efficacy while minimizing off-target toxicity. This article surveyed the recent progress and challenges of targeted nanomedicine in managing resistance and toxicity of cisplatin in both fundamental and clinical aspects. Particularly, we focused on three major mechanisms counteracting cisplatin sensitivity (decreased intracellular accumulation, increased cisplatin deactivation, and enhanced DNA repair/translesion synthesis) and correspondingly highlighted a few representative approaches to increase cisplatin sensitivity through improving the intracellular concentration of cisplatin and implementing combination therapy. Moreover, the requirements for future advancements in cisplatin delivery systems are rendered with emphasis on (i) understanding of nano-bio interaction and post-accumulation biological effects instead of overwhelmingly improving tumor accumulation, (ii) development of stimuli-responsive and/or actively-targeted nanomedicines, (iii) optimization of combination therapy, (iv) novel combinations targeting tumor microenvironment and immunotherapy. We postulate that cisplatin-based nanomedicines will continuously advance and potentially revolutionize oncological treatment.

Synergistic Disruption of Metabolic Homeostasis through Hyperbranched Poly(ethylene glycol) Conjugates as Nanotherapeutics to Constrain Cancer Growth

Combination therapy is a promising approach for effective treatment of tumors through synergistically regulating pathways. However, the synergistic effect is limited, likely by uncontrolled co-delivery of different therapeutic payloads in a single nanoparticle. Herein, a combination nanotherapeutic is developed by using two amphiphilic conjugates, hyperbranched poly(ethylene glycol)-pyropheophorbide-a (Ppa) (HP-P) and hyperbranched poly(ethylene glycol)-doxorubicin (DOX) (HP-D) to construct co-assembly nanoparticles (HP-PD NPs) for controllably co-loading and co-delivering Ppa and DOX. In vitro and in vivo antitumor studies confirm the synergistic effect of photodynamic therapy and chemotherapy from HP-PD NPs. Metabolic variations reveal that tumor suppression is associated with disruption of metabolic homeostasis, leading to reduced protein translation. This study uncovers the manipulation of metabolic changes in tumor cells through disruption of cellular homeostasis using HP-PD NPs and provides a new insight into the rational design of synergistic nanotherapeutics for combination therapy.

Engineering Supramolecular Nanomedicine for Targeted Near Infrared-triggered Mitochondrial Dysfunction to Potentiate Cisplatin for Efficient Chemophototherapy

Combinatorial cancer therapies based on nanomedicine have emerged as a promising strategy to achieve potentiated treatment efficiency. Herein, cisplatin (CDDP) prodrug (Pt-CD) and a mitochondria-targeted near-infrared (NIR) photosensitizer IR780 were combined to construct a multifunctional nanomedicine IR780@Pt NPs through a supramolecular self-assembly strategy. Targeted mitochondrial dysfunction of cancer cells was sufficiently induced under NIR laser irradiation through both photothermal and photodynamic effects, inhibiting the overactive mitochondrial energy pathways of cancer cells. The mitochondrial dysfunction significantly attenuated the crosstalk between mitochondria and nucleus via the cellular ATP energy chain, leading to obvious down-regulation of the key proteins of the nucleotide excision repair (NER) pathway. Thereby, the chemotherapeutic effect of CDDP could be significantly potentiated because of reduced DNA lesion repair capacity by ERCC1-XPF nuclease system. Moreover, IR780@Pt NPs exhibited excellent NIR fluorescence and photoacoustic (PA) imaging capacity for in vivo imaging-guided NIR laser treatment. Ultimately, the IR780@Pt NPs mediated combinatorial chemophototherapy achieved potentiated anticancer efficacy against cancer cells in vitro and tumor inhibition performance in vivo. Overall, this study highlighted the significance of nanomedicine mediated targeted induction of mitochondrial dysfunction to potentiate chemotherapy for efficient combinatorial cancer therapy.

8DEstablishment and validation of a hypoxia-related signature predicting prognosis in hepatocellular carcinoma

Background

Hypoxia plays a crucial role in immunotherapy of hepatocellular carcinoma (HCC) by changing the tumor microenvironment. Until now the association between hypoxia genes and prognosis of HCC remains obscure. We attempt to construct a hypoxia model to predict the prognosis in HCC.

Results

We screened out 3 hypoxia genes (ENO1, UGP2, TPI1) to make the model, which can predict prognosis in HCC. And this model emerges as an independent prognostic factor for HCC. A Nomogram was drawn to evaluate the overall survival in a more accurate way. Furthermore, immune infiltration state and immunosuppressive microenvironment of the tumor were detected in high-risk patients.

Conclusion

We establish and validate a risk prognostic model developed by 3 hypoxia genes, which could effectively evaluate the prognosis of HCC patients. This prognostic model can be used as a guidance for hypoxia modification in HCC patients undergoing immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02057-0.

Emerging Nano-Based Strategies Against Drug Resistance in Tumor Chemotherapy

Drug resistance is the most significant causes of cancer chemotherapy failure. Various mechanisms of drug resistance include tumor heterogeneity, tumor microenvironment, changes at cellular levels, genetic factors, and other mechanisms. In recent years, more attention has been paid to tumor resistance mechanisms and countermeasures. Nanomedicine is an emerging treatment platform, focusing on alternative drug delivery and improved therapeutic effectiveness while reducing side effects on normal tissues. Here, we reviewed the principal forms of drug resistance and the new possibilities that nanomaterials offer for overcoming these therapeutic barriers. Novel nanomaterials based on tumor types are an excellent modality to equalize drug resistance that enables gain more rational and flexible drug selectivity for individual patient treatment. With the emergence of advanced designs and alternative drug delivery strategies with different nanomaterials, overcome of multidrug resistance shows promising and opens new horizons for cancer therapy. This review discussed different mechanisms of drug resistance and recent advances in nanotechnology-based therapeutic strategies to improve the sensitivity and effectiveness of chemotherapeutic drugs, aiming to show the advantages of nanomaterials in overcoming of drug resistance for tumor chemotherapy, which could accelerate the development of personalized medicine.

Innovative nanochemotherapy for overcoming cancer multidrug resistance

Tumor multidrug resistance (MDR) is a phenomenon in which drug-resistant tumor cells are resistant to multiple other unexposed antitumor drugs with different structures and targets. MDR of cancer is a primary cause of clinical chemotherapy failure. With the progress of nanotechnology in the medical field, more and more research works have developed many nanotechnology-based strategies to challenge drug resistance. This review details the recent studies at the National Center for Nanoscience and Technology utilizing various nanochemotherapy strategies for overcoming chemotherapy resistance of tumor. We discuss the benefits and limitations of the diverse strategies, as well as possible ways to overcome these limitations. Importantly, in order to combat cancer chemotherapy resistance with nanomedicine, the mechanisms of drug endocytosis and subsequent fate need to be explored and focused on. In the meanwhile, due to the complexity and diversity of chemotherapy resistance mechanisms, the development of more intelligent and controllable nanodrugs may have greater scope for clinical application.

Multifunctional biomaterials that modulate oxygen levels in the tumor microenvironment

A characteristic feature of solid tumors is their low oxygen tension, which confers resistance to radiotherapy, photodynamic therapy, and chemotherapy. Therefore, to improve treatment outcomes, it is critical to develop biomaterials capable of targeted modulation of oxygen levels in tumors. In this review, we summarize four types of oxygen-modulating biomaterials, namely, oxygen-carrying biomaterials to deliver oxygen into tumors (e.g., perfluorocarbon and hemoglobin), oxygen-generating biomaterials to promote in situ oxygen generation (e.g., MnO2, catalase, and CuO), oxygen-consuming biomaterials to starve tumors (e.g., photosensitizer, glucose oxidase, and magnesium silicide), and oxygen-circulating biomaterials capable of both providing and consuming oxygen (e.g., ENBS-B). The current literature suggests that these biomaterials are useful for anticancer therapeutics. We present the key molecular mechanisms involved in modulating oxygen levels and the potential applications of these biomaterials in the context of hypoxic tumor treatment.

Early phago-/endosomal escape of platinum drugs via ROS-responsive micelles for dual cancer chemo/immunotherapy

Recent studies have indicated that cancer treatment based on immunotherapy alone is not viable. Combined treatment with other strategies is required to achieve the expected therapeutic effect. Reactive oxygen species (ROS) play an important role in regulating cancer cells and the tumor microenvironment, even in immune cells. However, rigorous regulation of the ROS level within the entire tumor tissue is difficult, limiting the application of ROS in cancer therapy. Therefore, we design an early phago-/endosome-escaping micelle that can release platinum-based drugs into the cytoplasm of macrophages and cancer cells, thereby enhancing the ROS levels of the entire tumor tissue; inducing apoptosis of cancer cells, down-regulation of CD47 expression of cancer cells, polarization of M1 macrophages, and phagocytosis of cancer cells by M1 macrophages; and achieving the dual effect of chemotherapy and macrophage-mediated immunotherapy.