Nanoenabled Intracellular Calcium Bursting for Safe and Efficient Reversal of Drug Resistance in Tumor Cells

Advance on combination therapy strategies based on biomedical nanotechnology induced ferroptosis for cancer therapeutics

Globally, cancer is a serious health problem. It is unfortunate that current anti-cancer strategies are insufficiently specific and damage the normal tissues. There's urgent need for development of new anti-cancer strategies. More recently, increasing attention has been paid to the new application of ferroptosis and nano materials in cancer research. Ferroptosis, a condition characterized by excessive reactive oxygen species-induced lipid peroxidation, as a new programmed cell death mode, exists in the process of a number of diseases, including cancers, neurodegenerative disease, cerebral hemorrhage, liver disease, and renal failure. There is growing evidence that inducing ferroptosis has proven to be an effective strategy against a variety of chemo-resistant cancer cells. Nano-drug delivery system based on nanotechnology provides a highly promising platform with the benefits of precise control of drug release and reduced toxicity and side effects. This paper reviews the latest advances of combination therapy strategies based on biomedical nanotechnology induced ferroptosis for cancer therapeutics. Given the new chances and challenges in this emerging area, we need more attention to the combination of nanotechnology and ferroptosis in the treatment of cancer in the future.

New Ca2+ based anticancer nanomaterials trigger multiple cell death targeting Ca2+ homeostasis for cancer therapy

Calcium ion (Ca2+) is a necessary element for human and Ca2+ homeostasis plays important roles in various cellular process and functions. Recent reaches have targeted on inducing Ca2+ overload (both intracellular and transcellular) for tumor therapy. With the development of nanotechnology, nanoplatform-mediated Ca2+ overload has been safe theranostic model for cancer therapy, and defined a special calcium overload-induced tumor cell death as "calcicoptosis". However, the underlying mechanism of calcicoptosis in cancer cells remains further identification. In this review, we summarized multiple cell death types due to Ca2+ overload that induced by novel anticancer nanomaterials in tumor cells, including apoptosis, autophagy, pyroptosis, and ferroptosis. We reviewed the roles of these anticancer nanomaterials on Ca2+ homeostasis, including transcellular Ca2+ influx and efflux, and intracellular Ca2+ change in the cytosolic and organelles, and connection of Ca2+ overload with other metal ions. This review provides the knowledge of these nano-anticancer materials-triggered calcicoptosis accompanied with multiple cell death by regulating Ca2+ homeostasis, which could not only enhance their efficiency and specificity, but also enlighten to design new cancer therapeutic strategies and biomedical applications.

Current advances in modulating tumor hypoxia for enhanced therapeutic efficacy

Hypoxia is a common feature of most solid tumors, which promotes the proliferation, invasion, metastasis, and therapeutic resistance of tumors. Researchers have been developing advanced strategies and nanoplatforms to modulate tumor hypoxia to enhance therapeutic effects. A timely review of this rapidly developing research topic is therefore highly desirable. For this purpose, this review first introduces the impact of hypoxia on tumor development and therapeutic resistance in detail. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are also systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We provide a detailed discussion of the rationale and research progress of these strategies. Through a review of current trends, it is hoped that this comprehensive overview can provide new prospects for clinical application in tumor treatment. STATEMENT OF SIGNIFICANCE: As a common feature of most solid tumors, hypoxia significantly promotes tumor progression. Advanced nanoplatforms have been developed to modulate tumor hypoxia to enhanced therapeutic effects. In this review, we first introduce the impact of hypoxia on tumor progression. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We discuss the rationale and research progress of the above strategies in detail, and finally introduce future challenges for treatment of hypoxic tumors. By reviewing the current trends, this comprehensive overview can provide new prospects for clinical translatable tumor therapy.

Photo-Controlled Calcium Overload from Endogenous Sources for Tumor Therapy

Designing reactive calcium-based nanogenerators to produce excess calcium ions (Ca2+ ) in tumor cells is an attractive tumor treatment method. However, nanogenerators that introduce exogenous Ca2+ are either overactive incapable of on-demand release, or excessively inert incapable of an overload of calcium rapidly. Herein, inspired by inherently diverse Ca2+ -regulating channels, a photo-controlled Ca2+ nanomodulator that fully utilizes endogenous Ca2+ from dual sources was designed to achieve Ca2+ overload in tumor cells. Specifically, mesoporous silica nanoparticles were used to co-load bifunctional indocyanine green as a photodynamic/photothermal agent and a thermal-sensitive nitric oxide (NO) donor (BNN-6). Thereafter, they were coated with hyaluronic acid, which served as a tumor cell-targeting unit and a gatekeeper. Under near-infrared light irradiation, the Ca2+ nanomodulator can generate reactive oxygen species that stimulate the transient receptor potential ankyrin subtype 1 channel to realize Ca2+ influx from extracellular environments. Simultaneously, the converted heat can induce BNN-6 decomposition to generate NO, which would open the ryanodine receptor channel in the endoplasmic reticulum and allow stored Ca2+ to leak. Both in vitro and in vivo experiments demonstrated that the combination of photo-controlled Ca2+ influx and release could enable Ca2+ overload in the cytoplasm and efficiently inhibit tumor growth.

Nanoenabled Intracellular Metal Ion Homeostasis Regulation for Tumor Therapy

Endogenous essential metal ions play an important role in many life processes, especially in tumor development and immune response. The approval of various metallodrugs for tumor therapy brings more attention to the antitumor effect of metal ions. With the deepening understanding of the regulation mechanisms of metal ion homeostasis in vivo, breaking intracellular metal ion homeostasis becomes a new means to inhibit the proliferation of tumor cells and activate antitumor immune response. Diverse nanomedicines with the loading of small molecular ion regulators or metal ions have been developed to disrupt metal ion homeostasis in tumor cells, with higher safety and efficiency than free small molecular ion regulators or metal compounds. This comprehensive review focuses on the latest progress of various intracellular metal ion homeostasis regulation-based nanomedicines in tumor therapy including calcium ion (Ca2+ ), ferrous ion (Fe2+ ), cuprous ion (Cu+ ), managanese ion (Mn2+ ), and zinc ion (Zn2+ ). The physiological functions and homeostasis regulation processes of ions are summarized to guide the design of metal ion regulation-based nanomedicines. Then the antitumor mechanisms of various ions-based nanomedicines and some efficient synergistic therapies are highlighted. Finally, the challenges and future developments of ion regulation-based antitumor therapy are also discussed, hoping to provide a reference for finding more effective metal ions and synergistic therapies.

Coexistence of a novel SRBD1-ALK, ALK-CACNA1D double-fusion in a lung adenocarcinoma patient and response to alectinib: A case report

A Chinese male patient with advanced lung adenocarcinoma experienced disease progression one and a half years after receiving first-line immunochemotherapy. The second biopsy was performed and tissue immunohistochemistry revealed Anaplastic lymphoma kinase (ALK) expression in the cytoplasm of tumor cells, so he began to receive Alectinib treatment. Then the next generation sequencing found double fusion variants of S1 RNA binding domain 1 (SRBD1)- ALK and ALK- Calcium voltage-gated channel subunit alpha1 D (CACNA1D). After continuous Alectinib treatment for 7 months, almost complete response (CR) was achieved. The patient is currently taking Alectinib for 13 months, the condition is stable, and is waiting for the next cycle of efficacy evaluation.

Oncofetal reprogramming in tumor development and progression: novel insights into cancer therapy

Emerging evidence indicates that cancer cells can mimic characteristics of embryonic development, promoting their development and progression. Cancer cells share features with embryonic development, characterized by robust proliferation and differentiation regulated by signaling pathways such as Wnt, Notch, hedgehog, and Hippo signaling. In certain phase, these cells also mimic embryonic diapause and fertilized egg implantation to evade treatments or immune elimination and promote metastasis. Additionally, the upregulation of ATP-binding cassette (ABC) transporters, including multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 1 (MRP1), and breast cancer-resistant protein (BCRP), in drug-resistant cancer cells, analogous to their role in placental development, may facilitate chemotherapy efflux, further resulting in treatment resistance. In this review, we concentrate on the underlying mechanisms that contribute to tumor development and progression from the perspective of embryonic development, encompassing the dysregulation of developmental signaling pathways, the emergence of dormant cancer cells, immune microenvironment remodeling, and the hyperactivation of ABC transporters. Furthermore, we synthesize and emphasize the connections between cancer hallmarks and embryonic development, offering novel insights for the development of innovative cancer treatment strategies.

Multifunctional Oxygen-Generating Nanoflowers for Enhanced Tumor Therapy

Sonodynamic therapy (SDT) and chemotherapy have received great attention as effective methods for tumor treatment. However, the inherent hypoxia of the tumor greatly hinders its therapeutic efficacy. In this work, a tumor microenvironment-responsive biodegradable nanoplatform SiO2-MnO2-PEG-Ce6&DOX (designated as SMPC&D) is fabricated by encapsulating manganese oxide (MnO2) into silica nanoparticles and anchoring poly(ethylene glycol) (PEG) onto the surface for tumor hypoxia relief and delivery, then loaded with sonosensitizer Chlorin e6 (Ce6) and chemotherapeutic drug doxorubicin (DOX) for hypoxic tumor treatment. We evaluated the physicochemical properties of SMPC&D nanoparticles and the tumor therapeutic effects of chemotherapy and SDT under ultrasound stimulation in vitro and in vivo. After endocytosis by tumor cells, highly expressed glutathione (GSH) triggers biodegradation of the nanoplatform and MnO2 catalyzes hydrogen peroxide (H2O2) to generate oxygen (O2), thereby alleviating tumor hypoxia. Depleting GSH and self-supplying O2 effectively improve the SDT efficiency both in vitro and in vivo. Ultrasonic stimulation promoted the release and cellular uptake of chemotherapy drugs. In addition, the relieved hypoxia reduced the efflux of chemotherapy drugs by downregulating the expression of the P-gp protein, which jointly improved the effect of chemotherapy. This study demonstrates that the degradable SMPC&D as a therapeutic agent can achieve efficient chemotherapy and SDT synergistic therapy for hypoxic tumors.

An injectable, in situ forming and NIR-responsive hydrogel persistently reshaping tumor microenvironment for efficient melanoma therapy

BACKGROUND

Melanoma is a highly aggressive form of skin cancer with increasing incidence and mortality rates. Chemotherapy, the primary treatment for melanoma, is limited by hypoxia-induced drug resistance and suppressed immune response at the tumor site. Modulating the tumor microenvironment (TME) to alleviate hypoxia and enhance immune response has shown promise in improving chemotherapy outcomes.

METHODS

In this study, a novel injectable and in situ forming hydrogel named MD@SA was developed using manganese dioxide (MnO2) nanosheets pre-loaded with the chemotherapy drug doxorubicin (DOX) and mixed with sodium alginate (SA). The sustainable drug delivery, oxygen generation ability, and photothermal property of MD@SA hydrogel were characterized. The therapeutic efficacy of hydrogel was studied in B16F10 in vitro and B16F10 tumor-bearing mice in vivo. The immune effects on macrophages were analyzed by flow cytometry, real-time quantitative reverse transcription PCR, and immunofluorescence analyses.

RESULTS

The MD@SA hydrogel catalyzed the tumoral hydrogen peroxide (H2O2) into oxygen, reducing the hypoxic TME, down-regulating hypoxia-inducible factor-1 alpha (HIF-1α) and drug efflux pump P-glycoprotein (P-gp). The improved TME conditions enhanced the uptake of DOX by melanoma cells, enhancing its efficacy and facilitating the release of tumor antigens. Upon NIR irradiation, the photothermal effect of the hydrogel induced tumor apoptosis to expose more tumor antigens, thus re-educating the M2 type macrophage into the M1 phenotype. Consequently, the MD@SA hydrogel proposes an ability to constantly reverse the hypoxic and immune-inhibited TME, which eventually restrains cancer proliferation.

CONCLUSION

The injectable and in situ forming MD@SA hydrogel represents a promising strategy for reshaping the TME in melanoma treatment. By elevating oxygen levels and activating the immune response, this hydrogel offers a synergistic approach for TME regulation nanomedicine.

Application of hyaluronic acid-based nanoparticles for cancer combination therapy

Cancer is a significant public health problem in the world. The treatment methods include surgery, chemotherapy, phototherapy, and immunotherapy. Due to their respective limitations, the treatment effect is often unsatisfactory, laying hidden dangers for metastasis and recurrence. Since their exceptional biocompatibility and excellent targeting capabilities, hyaluronic acid-based biomaterials have generated great interest as drug delivery methods for tumor therapy. Moreover, modified HA can self-assemble into hydrogels or nanoparticles (NPs) for precise drug administration. This article summarizes the application of HA-based NPs in combination therapy. Ultimately, it is anticipated that this research will offer guidance for creating various HA-based NPs utilized in numerous cancer therapies.

Synergistic ROS generation and directional overloading of endogenous calcium induce mitochondrial dysfunction in living cells

Taking advantage of endogenous Ca2+ to upregulate intramitochondrial Ca2+ level has become a powerful mean for mitochondrial dysfunction-mediated tumor therapy. However, the Ca2+ entered into mitochondria is limited ascribing to the uncontrollability and non-selectivity of endogenous Ca2+ transport. It remains a great challenge to make the maximum use of endogenous Ca2+ to ensure sufficient Ca2+ overloading in mitochondria. Herein, we smartly fabricate an intracellular Ca2+ directional transport channel to selectively transport endogenous Ca2+ from endoplasmic reticulum (ER) to mitochondria based on cascade release nanoplatform ABT-199@liposomes/doxorubicin@FeIII-tannic acid (ABT@Lip/DOX@Fe-TA). In tumor acidic microenvironment, Fe3+ ions are firstly released and reduced by tannic acid (TA) to Fe2+ for ROS generation. Subsequently, under the NIR light irradiation, the released ABT-199 molecules combine with ROS contribute to the formation of IP3R-Grp75-VDAC1 channel between ER and mitochondria, thus Ca2+ ions are directionally delivered and intramitochondrial Ca2+ level is significantly upregulated. The synergetic ROS generation and mitochondrial Ca2+ overloading effectively intensifies mitochondrial dysfunction, thereby achieving efficient tumor inhibition. This work presents a new insight and promising avenue for endogenous Ca2+-involved tumor therapies.

Research progress of calcium carbonate nanomaterials in cancer therapy: challenge and opportunity

Cancer has keeping the main threat to the health of human being. Its overall survival rate has shown rare substantial progress in spite of the improving diagnostic and treatment techniques for cancer in recent years. Indeed, such classic strategies for malignant tumor as surgery, radiation and chemotherapy have been developed and bring more hope to the patients, but still been accompanied by certain limitations, which include the challenge of managing large wound sizes, systemic toxic side effects, and harmful to the healthy tissues caused by imprecise alignment with tumors in radiotherapy. Furthermore, immunotherapy exhibits a limited therapeutic effect in advanced tumors which is reported only up to 25%-30%. The combination of nanomaterials and cancer treatment offers new hope for cancer patients, demonstrating strong potential in the field of medical research. Among the extensively utilized nanomaterials, calcium carbonate nanomaterials (CCNM) exhibit a broad spectrum of biomedical applications due to their abundant availability, cost-effectiveness, and exceptional safety profile. CCNM have the potential to elevate intracellular Ca2+ levels in tumor cells, trigger the mitochondrial damage and ultimately lead to tumor cell death. Moreover, compared with other types of nanomaterials, CCNM exhibit remarkable advantages as delivery systems owing to their high loading capacity, biocompatibility and biodegradability. The purpose of this review is to provide an overview of CCNM synthesis, focusing on summarizing its diverse roles in cancer treatment and the benefits and challenges associated with CCNM in cancer therapy. Hoping to present the significance of CCNM as for the clinical application, and summarize information for the design of CCNM and other types of nanomaterials in the future.

Physical Dissolution Combined with Photodynamic Depletion: A Two-Pronged Nanoapproach for Deoxygenation-Driven and Hypoxia-Activated Prodrug Therapy

Hypoxia may enhance the chemoresistance of cancer cells and can significantly compromise the effectiveness of chemotherapy. Many efforts have been made to relieve or reverse hypoxia by introducing more oxygen into the tumor microenvironment (TME). Acting in a diametrically opposite way, in the current study, a novel nanocarrier was designed to further exhaust the oxygen level of the hypoxic TME. By creating such an oxygen depleted TME, the hypoxia-selective cytotoxin can work effectively, and oxygen exhaustion triggered chemotherapy can be achieved. Herein, deoxygenation agent, FDA-approved perfluorocarbon (PFC) and photosensitizer indocyanine green (ICG) for oxygen depletion, along with the hypoxia-activating drug tirapazamine (TPZ), were coincorporated within the poly(lactic-co-glycolic acid) (PLGA) nanoemulsion (ICG/TPZ@PPs) for the treatment of hypoxic tumors. Following hypoxia amplifying through physical oxygen dissolution and photodynamic depletion in tumors, hypoxic chemotherapy could be effectively activated to improve multitreatment synergy. After achieving local tumor enrichment, PFC-mediated oxygen dissolution combined with further ICG-mediated photodynamic therapy (PDT) under near-infrared (NIR) laser irradiation could induce enhanced hypoxia, which would activate the antitumor activity of codelivered TPZ to synergize cytotoxicity. Remarkably, in vivo experimental results exhibited that deoxygenated ICG/TPZ@PPs-based photothermal therapy (PTT), PDT, and hypoxia activated chemotherapy have an excellent synergistic ablation of tumors without obvious side effects, and therefore, a broad prospect of application of this nanocarrier could be expected.

Hydroxyapatite nanoparticles induced calcium overload-initiated cancer cell-specific apoptosis through inhibition of PMCA and activation of calpain

Hydroxyapatite nanoparticles (HAPNs) have been reported to specifically induce apoptosis and sustained elevation of intracellular Ca2+ concentration ([Ca2+]i) in cancer cells. However, it remains unclear whether calcium overload, the abnormal intracellular accumulation of Ca2+, is the intrinsic cause of cell apoptosis, how HAPNs specifically evoke calcium overload in cancer cells, and which potential pathways were involved in apoptosis initiation in response to calcium overload. In this study, using various cancer and normal cells, we observed a positive correlation between the degree of increased [Ca2+]i and the specific toxicity of HAPNs. Moreover, chelating intracellular Ca2+ with BAPTA-AM inhibited HAPN-induced calcium overload and apoptosis, thus demonstrating that calcium overload was the main cause of HAPN-induced cytotoxicity in cancer cells. Notably, the dissolution of particles outside the cells did not affect cell viability or [Ca2+]i. In contrast, internalized HAPNs dissolved more readily in cancer cells than in normal cells and inhibited the activity of plasma membrane calcium-ATPase solely in cancer cells to prevent extrusion of excessive Ca2+, hence leading to calcium overload in tumor cells. Upon exposure to HAPNs, the Ca2+-sensitive cysteine protease calpain was activated and then cleaved the BH3-only protein Bid. Consequently, cytochrome c was released, and caspase-9 and -3 were activated, leading to mitochondrial apoptosis. However, these effects were alleviated by the calpain inhibitor calpeptin, confirming the involvement of calpain in HANP-induced apoptosis. Therefore, our results demonstrated that calcium overload induced by HAPNs caused cancer cell-specific apoptosis by inhibiting PMCA and activating calpain in tumor cells and thus may contribute to a more comprehensive understanding of biological effects of this nanomaterial and facilitate the development of calcium overload cancer therapy.

Escherichia coli-Based In Situ Triggerable Probe as an Amplifier for Sensitive Diagnosis and Penetrated Therapy of Cancer

Escherichia coli (E. coli) was used for cancer therapy due to the tumor-targeting, catalytic, and surface-reducing properties. Effective diagnosis combined with treatment of cancer based on E. coli, however, was rarely demonstrated. In this study, E. coli was used to surface reduce HAuCl4 and as a carrier to modify riboflavin (Rf) and luminol (E-Au@Rf@Lum). After targeted delivery to tumor, the E-Au@Rf@Lum probe could actively emit 425 nm blue-violet chemiluminescence (CL) to achieve cell imaging for cancer diagnosis. Furthermore, this light could in situ trigger the photosensitizer (Rf) through CL resonance energy transfer, which produces reactive oxygen species (ROS) for accurate photodynamic therapy. In return, the excessive ROS enhanced the blue-violet light which was further absorbed by Rf, and ROS production was cyclically amplified. Abundant ROS broke down the dense extracellular matrix network and penetrated deep into tumors. Besides, E. coli with excellent catalytic property could decompose H2O2 to O2 to relieve tumor hypoxia for a long time and enhance the photosensitized process of Rf. By self-illumination, effective penetration, and tumor hypoxia relief, this work opens a self-amplified therapy modality to tumor.

Non-interfacial self-assembly of synthetic protocells

BACKGROUND

Protocell refers to the basic unit of life and synthetic molecular assembly with cell structure and function. The protocells have great applications in the field of biomedical technology. Simulating the morphology and function of cells is the key to the preparation of protocells. However, some organic solvents used in the preparation process of protocells would damage the function of the bioactive substance. Perfluorocarbon, which has no toxic effect on bioactive substances, is an ideal solvent for protocell preparation. However, perfluorocarbon cannot be emulsified with water because of its inertia.

METHODS

Spheroids can be formed in nature even without emulsification, since liquid can reshape the morphology of the solid phase through the scouring action, even if there is no stable interface between the two phases. Inspired by the formation of natural spheroids such as pebbles, we developed non-interfacial self-assembly (NISA) of microdroplets as a step toward synthetic protocells, in which the inert perfluorocarbon was utilized to reshape the hydrogel through the scouring action.

RESULTS

The synthetic protocells were successfully obtained by using NISA-based protocell techniques, with the morphology very similar to native cells. Then we simulated the cell transcription process in the synthetic protocell and used the protocell as an mRNA carrier to transfect 293T cells. The results showed that protocells delivered mRNAs, and successfully expressed proteins in 293T cells. Further, we used the NISA method to fabricate an artificial cell by extracting and reassembling the membrane, proteins, and genomes of ovarian cancer cells. The results showed that the recombination of tumor cells was successfully achieved with similar morphology as tumor cells. In addition, the synthetic protocell prepared by the NISA method was used to reverse cancer chemoresistance by restoring cellular calcium homeostasis, which verified the application value of the synthetic protocell as a drug carrier.

CONCLUSION

This synthetic protocell fabricated by the NISA method simulates the occurrence and development process of primitive life, which has great potential application value in mRNA vaccine, cancer immunotherapy, and drug delivery.

Multisubcellular organelle-targeting nanoparticle for synergistic chemotherapy and photodynamic/photothermal tumor therapy

Background: The subcellular organelle-targeting strategy has attracted wide attention for a variety of reasons, including strong specificity, high accuracy, low dose administration and few side effects. It is an important and challenging task to explore the multisubcellular organelle-targeting strategy to achieve effective tumor treatment. Materials & methods: Using bovine serum albumin as a nanoreactor, BSA/Cu/NQ/IR780/DOX nanoparticles (NPs) were constructed via drug-induced protein self-assembly. Folic acid was then coupled to the surface of NPs to prepare folate receptor-targeted FA-BSA/Cu/NQ/IR780/DOX NPs. Results & conclusion: The FA-BSA/Cu/NQ/IR780/DOX NPs exhibit multifunctional properties, including multisubcellular organelle-targeting, induction of response release in the tumor microenvironment, fluorescence imaging capabilities and potential for synergistic chemotherapy and photodynamic/photothermal tumor therapy.

Selective Delivery of Tofacitinib Citrate to Hair Follicles Using Lipid-Coated Calcium Carbonate Nanocarrier Controls Chemotherapy-Induced Alopecia Areata

Chemotherapy-induced alopecia (CIA) is one of the common side effects in cancer treatment. The psychological distress caused by hair loss may cause patients to discontinue chemotherapy, affecting the efficacy of the treatment. The JAK inhibitor, Tofacitinib citrate (TFC), showed huge potential in therapeutic applications for treating baldness, but the systemic adverse effects of oral administration and low absorption rate at the target site limited its widespread application in alopecia. To overcome these problems, we designed phospholipid-calcium carbonate hybrid nanoparticles (PL/ACC NPs) for a topical application to target deliver TFC. The results proved that PL/ACC-TFC NPs showed excellent pH sensitivity and transdermal penetration in vitro. PL/ACC NPs offered an efficient follicular targeting approach to deliver TFC in a Cyclophosphamide (CYP)-induced alopecia areata mouse model. Compared to the topical application of TFC solution, PL/ACC-TFC NPs significantly inhibited apoptosis of mouse hair follicles and accelerated hair growth. These findings support that PL/ACC-TFC NPs has the potential for topical application in preventing and mitigating CYP-induced Alopecia areata.

Zn2+-interference and H2S-mediated gas therapy based on ZnS-tannic acid nanoparticles synergistic enhancement of cell apoptosis for specific treatment of prostate cancer

Zn²⁺ and H₂S are essential to maintain normal prostate function, and sometimes can evolve into weapons to attack and destroy prostate cancer (PCa) cells. Nevertheless, how to achieve the targeted and effective release of Zn²⁺ and H₂S, and reverse the concentration distribution within PCa tumor cells still highly challenging. Herein, combined with these pathological characteristics of prostate, we proposed a tumor microenvironment (TME) responsive Zn²⁺-interference and H₂S-mediated gas synergistic therapy strategy based on a nanoplatform of tannic acid (TA) modified zinc sulfide nanoparticles (ZnS@TA) for the specific treatment of PCa. Once the constructed pH-responsive ZnS@TA internalized by cancer cells, it would instantaneously decomposed in acidic TME, and explosively release excess Zn²⁺ and H₂S exceeding the cell self-regulation threshold. Meanwhile, the in situ produced Zn²⁺ and H₂S synergistic enhancement of cell apoptosis, which is evidenced to increase levels of Bax and Bax/Bcl-2 ratio, release of Cytochrome c in cancer cells, contributing to inhibit the growth of tumor. Moreover, the TA in cooperation with Zn²⁺ specifically limits the migration and invasion of PCa cells. Both in vitro and in vivo results demonstrate that the Zn²⁺-interference in combination with H₂S-mediated gas therapy achieves an excellent anti-tumor performance. Overall, this nanotheranostic synergistic therapy provides a promising direction for exploring new strategies for cancer treatment based on specific tumor pathological characteristics, and provides a new vision for promoting practical cancer therapy.

Calcium Phosphate-Based Nanoformulation Selectively Abolishes Phenytoin Resistance in Epileptic Neurons for Ceasing Seizures

Phenytoin (PHT) is a first-line antiepileptic drug in clinics, which could decrease neuronal bioelectric activity by blocking the voltage-operated sodium channels. However, the intrinsically low blood-brain-barrier (BBB)-crossing capability of PHT and upregulated expression level of the efflux transporter p-glycoprotein (P-gp) coded by the gene Abcb1 in epileptic neurons limit its efficacy in vivo. Herein, a nanointegrated strategy to overcome PHT resistance mechanisms for enhanced antiepileptic efficacy is reported. Specifically, PHT is first incorporated into calcium phosphate (CaP) nanoparticles through biomineralization, followed by the surface modification of the PEGylated BBB-penetrating TAT peptide. The CaP@PHT-PEG-TAT nanoformulation could effectively cross the BBB to be taken in by epileptic neurons. Afterward, the acidic lysosomal environment would trigger their complete degradation to release Ca²⁺ and PHT into the cytosol. Ca²⁺ ions would inhibit mitochondrial oxidative phosphorylation to reverse cellular hypoxia to block hypoxia-inducible factor-1α (Hif1α)-Abcb1-axis, as well as disrupt adenosine triphosphate generation, leading to simultaneous suppression of the expression and drug efflux capacity of P-gp to enhance PHT retention. This study offers an approach for effective therapeutic intervention against drug-resistant epilepsy.

Effect of Cellular and Microenvironmental Multidrug Resistance on Tumor-Targeted Drug Delivery in Triple-Negative Breast cancer

Multidrug resistance (MDR) reduces the efficacy of chemotherapy. Besides inducing the expression of drug efflux pumps, chemotherapy treatment alters the composition of the tumor microenvironment (TME), thereby potentially limiting tumor-directed drug delivery. To study the impact of MDR signaling in cancer cells on TME remodeling and nanomedicine delivery, we generated multidrug-resistant 4T1 triple-negative breast cancer (TNBC) cells by exposing sensitive 4T1 cells to gradually increasing doxorubicin concentrations. In 2D and 3D cell cultures, resistant 4T1 cells are presented with a more mesenchymal phenotype and produced increased amounts of collagen. While sensitive and resistant 4T1 cells showed similar tumor growth kinetics in vivo, the TME of resistant tumors was enriched in collagen and fibronectin. Vascular perfusion was also significantly increased. Fluorophore-labeled polymeric (∼10 nm) and liposomal (∼100 nm) drug carriers were administered to mice with resistant and sensitive tumors. Their tumor accumulation and penetration were studied using multimodal and multiscale optical imaging. At the whole tumor level, polymers accumulate more efficiently in resistant than in sensitive tumors. For liposomes, the trend was similar, but the differences in tumor accumulation were insignificant. At the individual blood vessel level, both polymers and liposomes were less able to extravasate out of the vasculature and penetrate the interstitium in resistant tumors. In a final in vivo efficacy study, we observed a stronger inhibitory effect of cellular and microenvironmental MDR on liposomal doxorubicin performance than free doxorubicin. These results exemplify that besides classical cellular MDR, microenvironmental drug resistance features should be considered when aiming to target and treat multidrug-resistant tumors more efficiently.

A Self-Reinforcing Nanoplatform for Highly Effective Synergistic Targeted Combinatary Calcium-Overload and Photodynamic Therapy of Cancer

While calcium-overload-mediated therapy (COMT) is a promising but largely untapped therapeutic strategy, combinatory therapy greatly boosts treatment outcomes with integrated merits of different therapies. Herein, a BPQD@CaO₂ -PEG-GPC3Ab nanoplatform is formulated by integrating calcium peroxide (CaO₂ ) and black phosphorus quantum dot (BPQD, photosensitizer) with active-targeting glypican-3 antibody (GPC3Ab), for combinatory photodynamic therapy (PDT) and COMT in response to acidic pH and near-infrared (NIR) light, wherein CaO₂ serves as the reservoir of calcium ions (Ca²⁺ ) and hydrogen peroxide (H₂ O₂ ). Navigated by GPC3Ab to tumor cells at acidic pH, the nanoparticle disassembles to CaO₂ and BPQD; CaO₂ produces COMT Ca²⁺ and H₂ O₂ , while H₂ O₂ makes oxygen (O₂ ) to promote PDT; under NIR irradiation BPQD facilitates not only the conversion of O₂ to singlet oxygen (¹ O₂ ) for PDT, but also moderate hyperthermia to accelerate NP dissociation to CaO₂ and BPQD, and conversions of CaO₂ to Ca²⁺ and H₂ O₂ , and H₂ O₂ to O₂ , to enhance both COMT and PDT. After supplementary ionomycin treatment to induce intracellular Ca²⁺ bursts, the multimodal therapeutics strikingly induce hepatocellular carcinoma apoptosis, likely through the activation of the calpains and caspases 12, 9, and 3, up-regulation of Bax and down-regulation of Bcl-2 proteins. This nanoplatform enables a mutually-amplifying and self-reinforcing synergistic therapy.

The combination of in situ photodynamic promotion and ion-interference to improve the efficacy of cancer therapy

Photodynamic therapy (PDT) is proved to be a promising modality for clinical cancer treatment. However, it also suffers from a key obstacle in association with its oxygen-dependent nature which greatly limits its effective application against hypoxic tumors. Herein, on the basis of the unique property of calcium peroxide (CaO₂), we propose an O₂-self-supply strategy for the promotion of PDT by combining the in situ O₂-generation characteristic of calcium peroxide with the photosensitive nature of porphyrin. A shell of ZIF-8 was synthesized surround the CaO₂ core to prevent the CaO₂ from premature decomposition and increased the loading of THPP efficiently. Depending on the in situ self-supply of O₂, the photosensitizer was able to exhibit an enhanced PDT effect that significantly inhibit the growth of tumor. Moreover, the enrichment of free calcium ions derived from the decomposition of CaO₂ under acidic tumor microenvironment also shows the unique ion-interference effect and contributes to the obvious inhibition against tumor growth. This work presents a synergistic strategy for the construction of a photodynamic promotion/ion-interference combined nano-platform which can also serve as an inspiration for the future design of effective nanocomposites in tumor treatment.

Looking into Endoplasmic Reticulum Stress: The Key to Drug-Resistance of Multiple Myeloma?

Multiple myeloma (MM) is the second most common hematologic malignancy, resulting from the clonal proliferation of malignant plasma cells within the bone marrow. Despite significant advances that have been made with novel drugs over the past two decades, MM patients often develop therapy resistance, especially to bortezomib, the first-in-class proteasome inhibitor that was approved for treatment of MM. As highly secretory monoclonal protein-producing cells, MM cells are characterized by uploaded endoplasmic reticulum stress (ERS), and rely heavily on the ERS response for survival. Great efforts have been made to illustrate how MM cells adapt to therapeutic stresses through modulating the ERS response. In this review, we summarize current knowledge on the mechanisms by which ERS response pathways influence MM cell fate and response to treatment. Moreover, based on promising results obtained in preclinical studies, we discuss the prospect of applying ERS modulators to overcome drug resistance in MM.

Robust Dual Enzyme Cascade-Catalytic Cholesterol Depletion for Reverse Tumor Multidrug Resistance

Although combination drugs and P-glycoprotein inhibitors are the main methods to solve multidrug resistance, these methods ignore the pathological structure of drug-resistant cells and extremely limit curative effect. Herein, a new paradigm of reversing multidrug resistance with abnormal expression of cholesterol as the target is proposed, which uses the cascade catalysis of "natural enzyme" cholesterol oxidase (COD) and "nanoenzyme" Cu²⁺ -modified zirconium-based metal-organic framework (ZrMOF(Cu)) to convert cholesterol into the highly cytotoxic hydroxyl radicals. The doxorubicin (DOX)-loaded nanoparticles (DOX@COD-MOF) can significantly reduce the cholesterol content of cancer cells via COD, which decrease the rigidity of drug resistant cancer cell membranes and restore the sensitivity of multidrug-resistant cells to DOX. Afterward, DOX@COD-MOF is encapsulated by cancer cell membranes (CCM) to construct a bionic "dual enzyme catalytic cascade nanoreactor" (DOX@COD-MOF@CCM). Such a rational design presents a preferential accumulation tendency to tumor sites due to the homologous targeting mechanism of CCM, and affords 94.4% in tumor growth suppression without systemic toxicity in vivo. This work aims to achieve the therapeutic purpose of high efficiency and low toxicity. It has the characteristics of "converting enemy into friend, " and opens up a promising way for effectively reversing multidrug resistance of tumors.

Emerging nanotechnology-based therapeutics to combat multidrug-resistant cancer

Cancer often develops multidrug resistance (MDR) when cancer cells become resistant to numerous structurally and functionally different chemotherapeutic agents. MDR is considered one of the principal reasons for the failure of many forms of clinical chemotherapy. Several factors are involved in the development of MDR including increased expression of efflux transporters, the tumor microenvironment, changes in molecular targets and the activity of cancer stem cells. Recently, researchers have designed and developed a number of small molecule inhibitors and derivatives of natural compounds to overcome various mechanisms of clinical MDR. Unfortunately, most of the chemosensitizing approaches have failed in clinical trials due to non-specific interactions and adverse side effects at pharmacologically effective concentrations. Nanomedicine approaches provide an efficient drug delivery platform to overcome the limitations of conventional chemotherapy and improve therapeutic effectiveness. Multifunctional nanomaterials have been found to facilitate drug delivery by improving bioavailability and pharmacokinetics, enhancing the therapeutic efficacy of chemotherapeutic drugs to overcome MDR. In this review article, we discuss the major factors contributing to MDR and the limitations of existing chemotherapy- and nanocarrier-based drug delivery systems to overcome clinical MDR mechanisms. We critically review recent nanotechnology-based approaches to combat tumor heterogeneity, drug efflux mechanisms, DNA repair and apoptotic machineries to overcome clinical MDR. Recent successful therapies of this nature include liposomal nanoformulations, cRGDY-PEG-Cy5.5-Carbon dots and Cds/ZnS core–shell quantum dots that have been employed for the effective treatment of various cancer sub-types including small cell lung, head and neck and breast cancers.

Tumor Microenvironment-Responsive Cu/CaCO3 -Based Nanoregulator for Mitochondrial Homeostasis Disruption-Enhanced Chemodynamic/Sonodynamic Therapy

The efficiency of reactive oxygen species (ROS)-mediated cancer therapy is restrained by intrinsic characteristics in the tumor microenvironment (TME), such as overexpressed glutathione (GSH), hypoxia and limited efficiency of H₂ O₂ . In this work, intelligent copper-dropped calcium carbonate loading sonosensitizer Ce6 nanoparticles (Cu/CaCO₃ @Ce6, CCC NPs) are established to realize TME-responsive self-supply of oxygen and successively Ca²⁺ -overloading-strengthened chemodynamic therapy/sonodynamic therapy (CDT/SDT). CCC NPs release Ca²⁺ , Cu²⁺ , and Ce6 in weakly acid and GSH-excessive TME. Released Cu²⁺ can not only consume GSH and turn into Cu⁺ via a redox reaction, but also provide CDT-creating hydroxyl radicals through the Fenton-like reaction. Under ultrasound irradiation, the intracellular oxidative stress is amplified profoundly relying on singlet oxygen outburst from SDT. Moreover, Ca²⁺ influx aggravates the mitochondrial disruption, which further accelerates the oxidation level. The facile and feasible design of the Cu-dropped CaCO₃ -based nanoregulators will be further developed as a paradigm in ROS-contributed cancer therapy.

Mitochondrial adaptation in cancer drug resistance: prevalence, mechanisms, and management

Drug resistance represents a major obstacle in cancer management, and the mechanisms underlying stress adaptation of cancer cells in response to therapy-induced hostile environment are largely unknown. As the central organelle for cellular energy supply, mitochondria can rapidly undergo dynamic changes and integrate cellular signaling pathways to provide bioenergetic and biosynthetic flexibility for cancer cells, which contributes to multiple aspects of tumor characteristics, including drug resistance. Therefore, targeting mitochondria for cancer therapy and overcoming drug resistance has attracted increasing attention for various types of cancer. Multiple mitochondrial adaptation processes, including mitochondrial dynamics, mitochondrial metabolism, and mitochondrial apoptotic regulatory machinery, have been demonstrated to be potential targets. However, recent increasing insights into mitochondria have revealed the complexity of mitochondrial structure and functions, the elusive functions of mitochondria in tumor biology, and the targeting inaccessibility of mitochondria, which have posed challenges for the clinical application of mitochondrial-based cancer therapeutic strategies. Therefore, discovery of both novel mitochondria-targeting agents and innovative mitochondria-targeting approaches is urgently required. Here, we review the most recent literature to summarize the molecular mechanisms underlying mitochondrial stress adaptation and their intricate connection with cancer drug resistance. In addition, an overview of the emerging strategies to target mitochondria for effectively overcoming chemoresistance is highlighted, with an emphasis on drug repositioning and mitochondrial drug delivery approaches, which may accelerate the application of mitochondria-targeting compounds for cancer therapy.

Copper-based metal-organic framework impedes triple-negative breast cancer metastasis via local estrogen deprivation and platelets blockade

Metastasis is one of the main causes of failure in the treatment of triple-negative breast cancer (TNBC). Abnormally estrogen level and activated platelets are the key driving forces for TNBC metastasis. Herein, an "ion/gas" bioactive nanogenerator (termed as IGBN), comprising a copper-based MOF and loaded cisplatin-arginine (Pt-Arg) prodrug is developed for metastasis-promoting tumor microenvironment reprogramming and TNBC therapy. The copper-based MOF not only serves as a drug carrier, but also specifically produces Cu2+ in tumors, which catalytic oxidizing estrogen to reduce estrogen levels in situ. Meanwhile, the rationally designed Pt-Arg prodrug reduced into cisplatin to significantly promote the generation of H2O2 in the tumor, then permitting self-augmented cascade NO gas generation by oxidizing Arg through a H2O2 self-supplied way, thus blocking platelet activation in tumor. We clarified that IGBN inhibited TNBC metastasis through local estrogen deprivation and platelets blockade, affording 88.4% inhibition of pulmonary metastasis in a 4T1 mammary adenocarcinoma model. Notably, the locally copper ion interference, NO gas therapy and cisplatin chemotherapy together resulted in an enhanced therapeutic efficacy in primary tumor ablation without significant toxicity. This "ion/gas" bioactive nanogenerator offers a robust and safe strategy for TNBC therapy.

Recent advances in anti-multidrug resistance for nano-drug delivery system

Chemotherapy for tumors occasionally results in drug resistance, which is the major reason for the treatment failure. Higher drug doses could improve the therapeutic effect, but higher toxicity limits the further treatment. For overcoming drug resistance, functional nano-drug delivery system (NDDS) has been explored to sensitize the anticancer drugs and decrease its side effects, which are applied in combating multidrug resistance (MDR) via a variety of mechanisms including bypassing drug efflux, controlling drug release, and disturbing metabolism. This review starts with a brief report on the major MDR causes. Furthermore, we searched the papers from NDDS and introduced the recent advances in sensitizing the chemotherapeutic drugs against MDR tumors. Finally, we concluded that the NDDS was based on several mechanisms, and we looked forward to the future in this field.

Engineering Chemotherapeutic-Augmented Calcium Phosphate Nanoparticles for Treatment of Intraperitoneal Disseminated Ovarian Cancer

Ovarian cancer is a common gynecologic malignancy with a high fatality rate. Intraperitoneal chemotherapy has been proved as an efficient clinical treatment for disseminated ovarian cancer. However, there are limitations for conventional small molecule drugs to achieve an ideal therapeutic effect. Herein, a synergistic treatment for intraperitoneally disseminated ovarian cancer was achieved by Arg-Gly-Asp (RGD)-modified amorphous calcium phosphate loading with doxorubicin (designated as RGD-CaPO/DOX). The engineered calcium-involved nanomedicine augmented the therapeutic effect of DOX by aggravating endoplasmic reticulum stress, calcium overload, and mitochondrial dysfunction, ultimately triggering mitochondrial apoptosis in the SKOV3 (human ovarian cancer) cell line. In an intraperitoneally disseminated tumor model, RGD modification and the weak negative surface potential of the NPs were beneficial for intraperitoneal retention and tumor targeting. Moreover, intraperitoneal injection of RGD-CaPO/DOX NPs resulted in a favorable antitumor effect. The mean survival time of SKOV3-bearing mice was significantly extended from 29 to 59 days with negligible toxicity. Therefore, this study has been designed to provide an effective chemotherapeutic-augmented treatment for intraperitoneally disseminated ovarian cancer.

Intelligent Nanoplatform with Multi Therapeutic Modalities for Synergistic Cancer Therapy

Chemodynamic therapy (CDT) has attracted increasing attention in tumor treatment but is limited by insufficient endogenous H₂O₂. Moreover, it is challenging for monotherapy to achieve a satisfactory outcome due to tumor complexity. Herein, we developed an intelligent nanoplatform that could respond to a tumor microenvironment to induce efficient CDT without complete dependence on H₂O₂ and concomitantly generate chemotherapy and oncosis therapy (OT). The nanoplatform was constructed by a calcium- and iron-doped mesoporous silica nanoparticle (CFMSN) loaded with dihydroartemisinin (DHA). After entering into cancer cells, the nanoplatform could directly convert the intracellular H₂O₂ into toxic •OH due to the Fenton-like activity of CFMSN. Meanwhile, the acidic microenvironment and endogenous chelating molecules triggered Ca²⁺ and Fe³⁺ release from the nanoplatform, causing particle collapse with accompanying DHA release for chemotherapy. Simultaneously, the released Ca²⁺ induced intracellular Ca²⁺-overloading for OT, which was further enhanced by DHA, while the released Fe³⁺ was reduced to reactive Fe²⁺ by intracellular glutathione, guaranteeing efficient Fenton reaction-mediated CDT. Moreover, Fe²⁺ cleaved the peroxy bonds of DHA to generate C-centered radicals to further amplify CDT. Both in vitro and in vivo results confirmed that the nanoplatform exhibited excellent anticancer efficacy via the synergistic effect of multi therapeutic modalities, which is extremely promising for high-efficient cancer therapy.

Ion Interference Therapy of Tumors Based on Inorganic Nanoparticles

As an essential substance for cell life activities, ions play an important role in controlling cell osmotic pressure balance, intracellular acid-base balance, signal transmission, biocatalysis and so on. The imbalance of ion homeostasis in cells will seriously affect the activities of cells, cause irreversible damage to cells or induce cell death. Therefore, artificially interfering with the ion homeostasis in tumor cells has become a new means to inhibit the proliferation of tumor cells. This treatment is called ion interference therapy (IIT). Although some molecular carriers of ions have been developed for intracellular ion delivery, inorganic nanoparticles are widely used in ion interference therapy because of their higher ion delivery ability and higher biocompatibility compared with molecular carriers. This article reviewed the recent development of IIT based on inorganic nanoparticles and summarized the advantages and disadvantages of this treatment and the challenges of future development, hoping to provide a reference for future research.

Bone mineral: A trojan horse for bone cancers efficient mitochondria targeted delivery and tumor eradication with nano hydroxyapatite containing doxorubicin

Efficient systemic pharmacological treatment of solid tumors is hampered by inadequate tumor concentration of cytostatics necessitating development of smart local drug delivery systems. To overcome this, we demonstrate that doxorubicin (DOX), a cornerstone drug used for osteosarcoma treatment, shows reversible accretion to hydroxyapatite (HA) of both nano (nHA) and micro (mHA) size. nHA particles functionalized with DOX get engulfed in the lysosome of osteosarcoma cells where the acidic microenvironment causes a disruption of the binding between DOX and HA. The released DOX then accumulates in the mitochondria causing cell starvation, reduced migration and apoptosis. The HA+DOX delivery system was also tested in-vivo on osteosarcoma bearing mice. Locally delivered DOX via the HA particles had a stronger tumor eradication effect compared to the controls as seen by PET-CT and immunohistochemical staining of proliferation and apoptosis markers. These results indicate that in addition to systemic chemotherapy, an adjuvant nHA could be used as a carrier for intracellular delivery of DOX for prevention of tumor recurrence after surgical resection in an osteosarcoma. Furthermore, we demonstrate that nHA particles are pivotal in this approach but a combination of nHA with mHA could increase the safety associated with particulate nanomaterials while maintaining similar therapeutic potential.

Phytic acid-modified CeO2 as Ca2+ inhibitor for a security reversal of tumor drug resistance

Ca²⁺ plays critical roles in the development of diseases, whereas existing various Ca regulation methods have been greatly restricted in their clinical applications due to their high toxicity and inefficiency. To solve this issue, with the help of Ca overexpressed tumor drug resistance model, the phytic acid (PA)-modified CeO₂ nano-inhibitors have been rationally designed as an unprecedentedly safe and efficient Ca²⁺ inhibitor to successfully reverse tumor drug resistance through Ca²⁺ negative regulation strategy. Using doxorubicin (Dox) as a model chemotherapeutic drug, the Ca²⁺ nano-inhibitors efficiently deprived intracellular excessive free Ca²⁺, suppressed P-glycoprotein (P-gp) expression and significantly enhanced intracellular drug accumulation in Dox-resistant tumor cells. This Ca²⁺ negative regulation strategy improved the intratumoral Dox concentration by a factor of 12.4 and nearly eradicated tumors without obvious adverse effects. Besides, nanocerias as pH-regulated nanozyme greatly alleviated the adverse effects of chemotherapeutic drug on normal cells/organs and substantially improved survivals of mice. We anticipate that this safe and effective Ca²⁺ negative regulation strategy has potentials to conquer the pitfalls of traditional Ca inhibitors, improve therapeutic efficacy of common chemotherapeutic drugs and serves as a facile and effective treatment platform of other Ca²⁺ associated diseases.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (further details of the XRD pattern of CeO₂, TEM images, XPS spectra, cellular uptake study, cytotoxicity data, apoptosis study, biodistribution, and biosecurity of nanocerias in vivo, etc.) is available in the online version of this article at 10.1007/s12274-022-4069-0.

Nanoplatform-mediated calcium overload for cancer therapy

Mitochondria, as the "the plant of power" of cells, have been extensively highlighted with biological functions of offering energy and participating in signaling pathways. In parallel, calcium (Ca2+) plays a...

Activatable Biomineralized Nanoplatform Remodels the Intracellular Environment of Multidrug-Resistant Tumors for Enhanced Ferroptosis/Apoptosis Therapy

Ferroptosis is a new form of regulated cell death with significant therapeutic prospect, but its application against drug-resistant tumor cells is challenging due to their ability to effuse antitumor agents via p-glycoprotein (P-gp) and anti-lipid peroxidation alkaline intracellular environment. Herein, an amorphous calcium phosphate (ACP)-based nanoplatform is reported for the targeted combinational ferroptosis/apoptosis therapy of drug resistant tumor cells by blocking the MCT4-mediated efflux of lactic acid (LA). The nanoplatform is fabricated through the biomineralization of doxorubicin-Fe²⁺ (DOX-Fe²⁺ ) complex and MCT4-inhibiting siRNAs (siMCT4) and can release them to the tumor cytoplasm after the hydrolysis of ACP and dissociation of DOX-Fe²⁺ in the acidic lysosomes. siMCT4 can inhibit MCT4 expression and force the glycolysis-generated lactic acid (LA) to remain in cytoplasm for rapid acidification. The nanoplatform-induced remodeling of the tumor intracellular environment can not only interrupt the ATP supply required for P-gp-dependent DOX effusion to enhance H₂ O₂ production, but also increase the overall catalytic efficiency of Fe²⁺ for the initiation and propagation of lipid peroxidation. These features could act in concert to enhance the efficacy of the combinational ferroptosis/chemotherapy and prolong the survival of tumor-bearing mice. This study may provide new avenues for the treatment of multidrug-resistant tumors.

Cetuximab-Modified Human Serum Albumin Nanoparticles Co-Loaded with Doxorubicin and MDR1 siRNA for the Treatment of Drug-Resistant Breast Tumors

Background

Breast cancer is the most prevalent cancer among women. Doxorubicin (DOX) is a common chemotherapeutic drug used to treat many different cancers. However, multidrug resistance limits the treatment of breast cancer. MDR1 siRNA (siMDR1) combinatorial therapy has attracted significant attention as a breakthrough therapy for multidrug resistance in tumors. However, naked siRNA is easily degraded by enzymatic hydrolysis requiring an siRNA carrier for its protection. Human serum albumin (HSA) was selected as the carrier due to its excellent biocompatibility, non-toxicity, and non-immunogenicity. Cetuximab was used to modify the HSA nanoparticles in order to target the tumor tissues.

Methods

This study used a central composite design response surface methodology (CCD-RSM) to investigate the optimal formula for HSA NPs preparation. Cex-HSA/DOX/MDR1 siRNA (C-H/D/M) was characterized by dynamic light scattering and transmission electron microscopy. The efficacy of C-H/D/M tumor growth inhibitory activity was investigated in vitro and in vivo using confocal imaging, MTT assay, and an MCF-7/ADR tumor-bearing mice model. RT–qPCR, ELISA analysis, and flow cytometry were used to investigate the in vitro antitumor mechanisms of C-H/D/M.

Results

The diameter and PDI of the C-H/D/M were 173.57 ± 1.30 nm and 0.027 ± 0.004, respectively. C-H/D/M promoted and maintained the sustained release and the uptake of DOX significantly. After transfection, the MDR1 mRNA and P-gp expression levels were down-regulated by 44.31 ± 3.6% (P < 0.01) and 38.08 ± 2.4% (P < 0.01) in an MCF-7/ADR cell line. The fluorescent images of the treated BALB/c nude mice revealed that C-H/D/M achieved targeted delivery of siMDR1 and DOX into the tumor tissue. The in vivo tumor inhibition results demonstrated that the tumor inhibition rate of the C-H/D/M treated group was 54.05% ± 1.25%. The biosafety results indicated that C-H/D/M did not induce significant damages to the main organs in vivo.

Conclusion

C-H/D/M can be used as an ideal non-viral tumor-targeting vector to overcome MDR and enhance the antitumor effect.

Targeted delivery and stimulus-responsive release of anticancer drugs for efficient chemotherapy

Chemotherapy is currently an irreplaceable strategy for cancer treatment. Doxorubicin hydrochloride (DOX) is a clinical first-line drug for cancer chemotherapy. While its efficacy for cancer treatment is greatly compromised due to invalid enrichment or serious side effects. To increase the content of intracellular targets and boost the antitumor effect of DOX, a novel biotinylated hyaluronic acid-guided dual-functionalized CaCO₃-based drug delivery system (DOX@BHNP) with target specificity and acid-triggered drug-releasing capability was synthesized. The ability of the drug delivery system on enriching DOX in mitochondria and nucleus, which further cause significant tumor inhibition, were investigated to provide a more comprehensive understanding of this CaCO₃-based drug delivery system. After targeted endocytosis by tumor cells, DOX could release faster in the weakly acidic lysosome, and further enrich in mitochondria and nucleus, which cause mitochondrial destruction and nuclear DNA leakage, and result in cell cycle arrest and cell apoptosis. Virtually, an effective tumor inhibition was observed in vitro and in vivo. More importantly, the batch-to-batch variation of DOX loading level in the DOX@BHNP system is negligible, and no obvious histological changes in the main organs were observed, indicating the promising application of this functionalized drug delivery system in cancer treatment.

Tumor-activatable biomineralized nanotherapeutics for integrative glucose starvation and sensitized metformin therapy

Metformin is a clinically-approved anti-diabetic drug with emerging antitumor potential, but its antitumor activity is highly susceptible to local glucose abundance. Herein, we construct a nanotherapeutic platform based on biocompatible constituents to sensitize tumor cells for metformin therapy via cooperative glucose starvation. The nanoplatform was synthesized through the spontaneous biomineralization of glucose oxidase (GOx) and metformin in amorphous calcium phosphate nanosubstrate, which was further modified with polyethylene glycol and cRGD ligands. This biomineralized nanosystem could efficiently deliver the therapeutic payloads to tumor cells in a targeted and bioresponsive manner. Here GOx could catalyze the oxidation of glucose into gluconic acid and H₂O₂, thus depleting the glucose in tumor intracellular compartment while accelerating the release of the entrapped therapeutic payloads. The selective glucose deprivation would not only disrupt tumor energy metabolism, but also upregulate the PP2A regulatory subunit B56δ and sensitize tumor cells to the metformin-induced CIP2A inhibition, leading to efficient apoptosis induction via PP2A-GSK3β-MCL-1 axis with negligible side effects. This study may offer new avenues for targeted tumor therapy in the clinical context.

Image-Guided TME-Improving Nano-Platform for Ca2+ Signal Disturbance and Enhanced Tumor PDT

Dysfunction of the calcium balancing system and disruption of calcium distribution can induce abnormal intracellular calcium overload, further causing serious damage and even cell death, which provides a potential therapeutic approach for tumor treatment. Herein, a nano-platform, which includes UCNPs-Ce6@RuR@mSiO₂ @PL-HA NPs (UCRSPH) and SA-CaO₂ nanoparticles, is prepared for improving the tumor micro-environment (TME), Ca²⁺ signal disturbance as well as enhanced photodynamic tumor therapy (PDT). UCRSPH combined with SA-CaO₂ can alter TME and relieve hypoxia of the tumor to realize self-reinforcing PDT under near-IR irradiation (980 nm). The ruthenium red (RuR) in the UCRSPH NPs can be released to the cytoplasm after endocytosis of the nanoparticles, target Ca²⁺ channel proteins on the endoplasmic reticulum and mitochondria, sarcoplasmic reticulum Ca²⁺ -ATPase (SERCA), and mitochondrial calcium uniporter (MCU). The combined participation of nanoparticles and RuR promotes Ca²⁺ imbalance and cytoplasmic calcium overload with the assistance of CaO₂ , and provides tumor cells higher sensitivity to PDT. Furthermore, the nano-platform also provides fluorescence imaging and calcification computed tomography imaging for in vivo treatment guidance. In conclusion, this image-guided nano-platform show potential for highly specific, efficient combined therapy against tumor cells with minimal side-effects to normal cells by integrating TME improvement, self-reinforcing PDT, and Ca²⁺ signal disturbance.

Calcium Peroxide-Based Nanosystem with Cancer Microenvironment-Activated Capabilities for Imaging Guided Combination Therapy via Mitochondrial Ca2+ Overload and Chemotherapy

Mitochondria are the "power plant" of the cell, providing a constant source of energy, and are involved in a variety of intracellular signaling pathways. Among these pathways, Ca²⁺ homeostasis is closely related to the normal function of mitochondria. By destroying the Ca²⁺ steady state of mitochondria and disrupting their multiple cellular activities, tumor cell killing can be achieved. In addition, the presence of an intracellular oxidative stress state triggers the closure of cellular calcium channels, which leads to intracellular Ca²⁺ retention and enrichment. We designed a targeted and tumor microenvironment (TME)-responsive CaO₂-based nanosystem that can selectively target cancer cells for pH-controlled degradation and drug release, alter cellular physiological mechanisms by disrupting Ca²⁺ homeostasis in an artificial manner, and introduce mitochondrial Ca²⁺ excess-mediated apoptosis. Meanwhile, the production of Ca(OH)₂ will raise the pH of the microenvironment and subsequently promote the oxidation process of glutathione by H₂O₂ released from CaO₂ degradation, achieving the goal of remodeling TME. Moreover, calcium overload of tumor cells and calcification of tissues can both inhibit tumor growth and act as a contrast agent for computed tomography imaging.

Cell death as a result of calcium signaling modulation: A cancer-centric prospective

Calcium ions (Ca²⁺) and the complex regulatory system governed by Ca²⁺ signaling have been described to be of crucial importance in numerous aspects related to cell life and death decisions, especially in recent years. The growing attention given to this second messenger is justified by the pleiotropic nature of Ca²⁺-binding proteins and transporters and their consequent involvement in cell fate decisions. A growing number of works highlight that deregulation of Ca²⁺ signaling and homoeostasis is often deleterious and drives pathological conditions; in particular, a disruption of the main Ca²⁺-mediated death mechanisms may lead to uncontrolled cell growth that results in cancer. In this work, we review the latest useful evidence to better understand the complex network of pathways by which Ca²⁺ regulates cell life and death decisions.

Recent progress in nanomedicine for enhanced cancer chemotherapy

As one of the most important cancer treatment strategies, conventional chemotherapy has substantial side effects and leads easily to cancer treatment failure. Therefore, exploring and developing more efficient methods to enhance cancer chemotherapy is an urgently important problem that must be solved. With the development of nanotechnology, nanomedicine has showed a good application prospect in improving cancer chemotherapy. In this review, we aim to present a discussion on the significant research progress in nanomedicine for enhanced cancer chemotherapy. First, increased enrichment of drugs in tumor tissues relying on different targeting ligands and promoting tissue penetration are summarized. Second, specific subcellular organelle-targeted chemotherapy is discussed. Next, different combinational strategies to reverse multidrug resistance (MDR) and improve the effective intracellular concentration of therapeutics are discussed. Furthermore, the advantages of combination therapy for cancer treatment are emphasized. Finally, we discuss the major problems facing therapeutic nanomedicine for cancer chemotherapy, and propose possible future directions in this field.

Nanomedicines for combating multidrug resistance of cancer

Chemotherapy typically involves the use of specific chemodrugs to inhibit the proliferation of cancer cells, but the frequent emergence of a variety of multidrug-resistant cancer cells poses a tremendous threat to our combat against cancer. The fundamental causes of multidrug resistance (MDR) have been studied for decades, and can be generally classified into two types: one is associated with the activation of diverse drug efflux pumps, which are responsible for translocating intracellular drug molecules out of the cells; the other is linked with some non-efflux pump-related mechanisms, such as antiapoptotic defense, enhanced DNA repair ability, and powerful antioxidant systems. To overcome MDR, intense efforts have been made to develop synergistic therapeutic strategies by introducing MDR inhibitors or combining chemotherapy with other therapeutic modalities, such as phototherapy, gene therapy, and gas therapy, in the hope that the drug-resistant cells can be sensitized toward chemotherapeutics. In particular, nanotechnology-based drug delivery platforms have shown the potential to integrate multiple therapeutic agents into one system. In this review, the focus was on the recent development of nanostrategies aiming to enhance the efficiency of chemotherapy and overcome the MDR of cancer in a synergistic manner. Different combinatorial strategies are introduced in detail and the advantages as well as underlying mechanisms of why these strategies can counteract MDR are discussed. This review is expected to shed new light on the design of advanced nanomedicines from the angle of materials and to deepen our understanding of MDR for the development of more effective anticancer strategies. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.