Combination of cancer-specific prodrug nanoparticle with Bcl-2 inhibitor to overcome acquired drug resistance

Advances in 2,3-Dimethylmaleic Anhydride (DMMA)-Modified Nanocarriers in Drug Delivery Systems

Cancer represents a significant threat to human health. The cells and tissues within the microenvironment of solid tumors exhibit complex and abnormal properties in comparison to healthy tissues. The efficacy of nanomedicines is inhibited by the presence of substantial and complex physical barriers in the tumor tissue. The latest generation of intelligent drug delivery systems, particularly nanomedicines capable of charge reversal, have shown promise in addressing this issue. These systems can transform their charge from negative to positive upon reaching the tumor site, thereby enhancing tumor penetration via transcytosis and promoting cell internalization by interacting with the negatively charged cell membranes. The modification of nanocarriers with 2,3-dimethylmaleic anhydride (DMMA) and its derivatives, which are responsive to weak acid stimulation, represents a significant advance in the field of charge-reversal nanomedicines. This review provides a comprehensive examination of the recent insights into DMMA-modified nanocarriers in drug delivery systems, with a particular focus on their potential in targeted therapeutics. It also discusses the synthesis of DMMA derivatives and their role in charge reversal, shell detachment, size shift, and ligand reactivation mechanisms, offering the prospect of a tailored, next-generation therapeutic approach to overcome the diverse challenges associated with cancer therapy.

Topical statins as antifungals: a review

Cutaneous fungal infections affect millions around the world. However, severe, multi-resistant fungal infections are increasingly being reported over the past years. As a result of the high rate of resistance which urged for drug repurposing, statins were studied and found to have multiple pleiotropic effects, especially when combined with other already-existing drugs. An example of this is the synergism found between several typical antifungals and statins, such as antifungals Imidazole and Triazole with a wide range of statins shown in this review. The main mechanisms in which they exert an antifungal effect are ergosterol inhibition, protein prenylation, mitochondrial disruption, and morphogenesis/mating inhibition. This article discusses multiple in vitro studies that have proven the antifungal effect of systemic statins against many fungal species, whether used alone or in combination with other typical antifungals. However, as a result of the high rate of drug-drug interactions and the well-known side effects of systemic statins, topical statins have become of increasing interest. Furthermore, patients with dyslipidemia treated with systemic statins who have a new topical fungal infection could benefit from the antifungal effect of their statin. However, it is still not indicated to initiate systemic statins in patients with topical mycotic infections if they do not have another indication for statin use, which raises the interest in using topical statins for fungal infections. This article also tackles the different formulations that have been studied to enhance topical statins' efficacy, as well as the effect of different topical statins on distinct dermatologic fungal diseases.

Unlocking the Therapeutic Potential of BCL-2 Associated Protein Family: Exploring BCL-2 Inhibitors in Cancer Therapy

Apoptosis, programmed cell death pathway, is a vital physiological mechanism that ensures cellular homeostasis and overall cellular well-being. In the context of cancer, where evasion of apoptosis is a hallmark, the overexpression of anti-apoptotic proteins like Bcl2, Bcl-xL and Mcl-1 has been documented. Consequently, these proteins have emerged as promising targets for therapeutic interventions. The BCL-2 protein family is central to apoptosis and plays a significant importance in determining cellular fate serving as a critical determinant in this biological process. This review offers a comprehensive exploration of the BCL-2 protein family, emphasizing its dual nature. Specifically, certain members of this family promote cell survival (known as anti-apoptotic proteins), while others are involved in facilitating cell death (referred to as pro-apoptotic and BH3-only proteins). The potential of directly targeting these proteins is examined, particularly due to their involvement in conferring resistance to traditional cancer therapies. The effectiveness of such targeting strategies is also discussed, considering the tumor's propensity for anti-apoptotic pathways. Furthermore, the review highlights emerging research on combination therapies, where BCL-2 inhibitors are used synergistically with other treatments to enhance therapeutic outcomes. By understanding and manipulating the BCL-2 family and its associated pathways, we open doors to innovative and more effective cancer treatments, offering hope for resistant and aggressive cases.

Co-delivery of siBcl-2 and PTX with mitochondria-targeted functions to overcoming multidrug resistance

Multidrug resistance (MDR) poses a significant impediment to the efficacy of chemotherapy in clinical settings. Despite Paclitaxel (PTX) being designated as the primary pharmaceutical agent for treating recurrent and metastatic breast cancer, the emergence of PTX resistance frequently results in therapeutic shortcomings, representing a substantial obstacle in clinical breast cancer management. In response, we developed a delivery system exhibiting dual specificity for both tumors and mitochondria. This system facilitated the sequential administration of small interfering B-cell lymphoma-2 (siBcl-2) and PTX to the tumor cytoplasm and mitochondria, respectively, with the aim of surmounting PTX resistance in tumor cells through the activation of the mitochondrial apoptosis pathway. Notably, we employed genetic engineering techniques to fabricate a recombinant ferritin containing the H-subunit (HFn), known for its tumor-targeting capabilities, for loading siBcl-2. This HFn-siBcl-2 complex was then combined with positively charged Triphenylphosphine-Liposome@PTX (TL@PTX) nanoparticles (NPs) to formulate HFn/siBcl-2@TL/PTX. Guided by HFn, these nanoparticles efficiently entered cells and released siBcl-2 through the action of triphenylphosphine (TPP)-mediated "proton sponge," thereby precisely modulating the expression of Bcl-2 protein. Simultaneously, PTX was directed to the mitochondria through the accurate targeting of TL@PTX, synergistically initiating the mitochondrial apoptosis pathway and effectively suppressing PTX resistance both in vitro and in vivo. In conclusion, the development of this dual-targeting delivery system presents a promising therapeutic strategy for overcoming PTX resistance in the clinical treatment of breast cancer.

Multi-functional nanomedicines for combinational cancer immunotherapy that transform cold tumors to hot tumors

INTRODUCTION

Currently, cancer immunotherapy is widely used as a groundbreaking method that can completely cure advanced cancers. However, this new immunotherapy has the challenge of low patient response, which is often due to many patients' tumors having an immunosuppressive environment, known as cold tumors.

AREAS COVERED

This review aims to introduce various nanomedicine-derived combinational cancer immunotherapy that can transform cold tumor into hot tumors. Initially, we discuss new technologies for combinational immunotherapy based on multifunctional nanomedicines that can deliver combinational immunogenic cell death (ICD) inducers, immune checkpoint blockades (ICBs) and immune modulators (IMs) to targeted tumor tissues at the same time. Ultimately, we highlight how multifunctional nanomedicines for combinational cancer immunotherapy can be used to transform cold tumor into hot tumors against advanced cancers.

EXPERT OPINION

Nanomedicine-derived combinational cancer immunotherapy for delivering multiple ICD inducers, ICBs, and IMs at the same time is recognized as a new potential technology that can activate tumor immunity and simultaneously increase the therapeutic efficacy of immune cells that can transform effectively the cold tumors into hot tumors. Finally, nanomedicine-derived combinational cancer immunotherapy can solve the serious problems of low therapeutic efficacy that occurs when treating single drug or simple combinational drugs in cancer immunotherapy.

Cancer cell-specific and pro-apoptotic SMAC peptide-doxorubicin conjugated prodrug encapsulated aposomes for synergistic cancer immunotherapy

BACKGROUND

Immunogenic cell death (ICD) is a crucial approach to turn immunosuppressive tumor microenvironment (ITM) into immune-responsive milieu and improve the response rate of immune checkpoint blockade (ICB) therapy. However, cancer cells show resistance to ICD-inducing chemotherapeutic drugs, and non-specific toxicity of those drugs against immune cells reduce the immunotherapy efficiency.

METHODS

Herein, we propose cancer cell-specific and pro-apoptotic liposomes (Aposomes) encapsulating second mitochondria-derived activator of caspases mimetic peptide (SMAC-P)-doxorubicin (DOX) conjugated prodrug to potentiate combinational ICB therapy with ICD. The SMAC-P (AVPIAQ) with cathepsin B-cleavable peptide (FRRG) was directly conjugated to DOX, and the resulting SMAC-P-FRRG-DOX prodrug was encapsulated into PEGylated liposomes.

RESULTS

The SMAC-P-FRRG-DOX encapsulated PEGylated liposomes (Aposomes) form a stable nanostructure with an average diameter of 109.1 ± 5.14 nm and promote the apoptotic cell death mainly in cathepsin B-overexpressed cancer cells. Therefore, Aposomes induce a potent ICD in targeted cancer cells in synergy of SMAC-P with DOX in cultured cells. In colon tumor models, Aposomes efficiently accumulate in targeted tumor tissues via enhanced permeability and retention (EPR) effect and release the encapsulated prodrug of SMAC-P-FRRG-DOX, which is subsequently cleaved to SMAC-P and DOX in cancer cells. Importantly, the synergistic activity of inhibitors of apoptosis proteins (IAPs)-inhibitory SMAC-P sensitizing the effects of DOX induces a potent ICD in the cancer cells to promote dendritic cell (DC) maturation and stimulate T cell proliferation and activation, turning ITM into immune-responsive milieu.

CONCLUSIONS

Eventually, the combination of Aposomes with anti-PD-L1 antibody results in a high rate of complete tumor regression (CR: 80%) and also prevent the tumor recurrence by immunological memory established during treatments.

Targeting Alpha7 Nicotinic Acetylcholine Receptors in Lung Cancer: Insights, Challenges, and Therapeutic Strategies

Alpha7 nicotinic acetylcholine receptor (α7 nAChR) is an ion-gated calcium channel that plays a significant role in various aspects of cancer pathogenesis, particularly in lung cancer. Preclinical studies have elucidated the molecular mechanism underlying α7 nAChR-associated lung cancer proliferation, chemotherapy resistance, and metastasis. Understanding and targeting this mechanism are crucial for developing therapeutic interventions aimed at disrupting α7 nAChR-mediated cancer progression and improving treatment outcomes. Drug research and discovery have determined natural compounds and synthesized chemical antagonists that specifically target α7 nAChR. However, approved α7 nAChR antagonists for clinical use are lacking, primarily due to challenges related to achieving the desired selectivity, efficacy, and safety profiles required for effective therapeutic intervention. This comprehensive review provided insights into the molecular mechanisms associated with α7 nAChR and its role in cancer progression, particularly in lung cancer. Furthermore, it presents an update on recent evidence about α7 nAChR antagonists and addresses the challenges encountered in drug research and discovery in this field.

Peptide-modified bioresponsive chondroitin sulfate micelles for targeted doxorubicin delivery in triple-negative breast cancer

Triple-negative breast cancer is an offensive tumor that is highly challenging to cure. In this study, we developed novel polymeric nanoparticles that target dual receptors and respond to reducing conditions for chemotherapeutic drug release in the treatment of triple-negative breast cancer. Then we synthesized and characterized a targeted peptide-grafted chondroitin sulfate A-ss-deoxycholic acid (TCSSD) copolymer and prepare doxorubicin (DOX)-loaded TCSSD (TCSSD-D) micelles high-loading content. The bioresponsive drug release of TCSSD-D nanoparticles was demonstrated in a glutathione-containing phosphate buffer solution. We found that TCSSD-D effectively targeted CD44 and P-selectin receptors both in vitro and in vivo. TCSSD-D micelles were higher cytotoxicity and cellular uptake than unmodified DOX-containing micelles in MDA-MB-231 cells. Furthermore, TCSSD-D micelles showed the strongest suppression of tumor growth among three DOX-based formulations in triple-negative MDA-MB-231-bearing nude mice. These results suggest that amphiphilic TCSSD nanoparticles can serve as a targeted and intelligent delivery vehicle for triple-negative breast cancer therapy.

In vivo toxicity evaluation of tumor targeted glycol chitosan nanoparticles in healthy mice: repeated high-dose of glycol chitosan nanoparticles potentially induce cardiotoxicity

BACKGROUND

Glycol chitosan nanoparticles (CNPs) have emerged as an effective drug delivery system for cancer diagnosis and treatment. Although they have great biocompatibility owing to biodegradable chemical structure and low immunogenicity, sufficient information on in vivo toxicity to understand the potential risks depending on the repeated high-dose have not been adequately studied. Herein, we report the results of in vivo toxicity evaluation for CNPs focused on the number and dose of administration in healthy mice to provide a toxicological guideline for a better clinical application of CNPs.

RESULTS

The CNPs were prepared by conjugating hydrophilic glycol chitosan with hydrophobic 5β-cholanic acid and the amphiphilic glycol chitosan-5β-cholanic acid formed self-assembled nanoparticles with its concentration-dependent homogeneous size distributions (265.36-288.3 nm) in aqueous condition. In cell cultured system, they showed significantly high cellular uptake in breast cancer cells (4T1) and cardiomyocytes (H9C2) than in fibroblasts (L929) and macrophages (Raw264.7) in a dose- and time-dependent manners, resulting in severe necrotic cell death in H9C2 at a clinically relevant highly concentrated condition. In particular, when the high-dose (90 mg/kg) of CNPs were intravenously injected into the healthy mice, considerable amount was non-specifically accumulated in major organs (liver, lung, spleen, kidney and heart) after 6 h of injection and sustainably retained for 72 h. Finally, repeated high-dose of CNPs (90 mg/kg, three times) induced severe cardiotoxicity accompanying inflammatory responses, tissue damages, fibrotic changes and organ dysfunction.

CONCLUSIONS

This study demonstrates that repeated high-dose CNPs induce severe cardiotoxicity in vivo. Through the series of toxicological assessments in the healthy mice, this study provides a toxicological guideline that may expedite the application of CNPs in the clinical settings.

Beyond basic research: the contribution of cathepsin B to cancer development, diagnosis and therapy

INTRODUCTION

In view of other candidate proteins from the cathepsin family of proteases holding great potential in being targeted during cancer therapy, the importance of Cathepsin B (CtsB) stands out as being truly exceptional. Based on its contribution to oncogenesis, its intimate connection with regulating apoptosis and modulating extracellular and intracellular functions through its secretion or compartmentalized subcellular localization, collectively highlight its complex molecular involvement with a myriad of normal and pathological regulatory processes. Despite its complex functional nature, CtsB is emerging as one of the few cathepsin proteases that has been extensively researched to yield tangible outcomes for cancer therapy.

AREAS COVERED

In this article, we review the scientific literature that has justified or shaped the importance of CtsB expression in cancer progression, from the perspective of highlighting a paradigm that is rapidly changing from basic research toward a broader clinical and translational context.

EXPERT OPINION

In doing so, we detail its maturation as a diagnostic marker through describing the development of CtsB-specific Activity-Based Probes, the rapid evolution of these toward a new generation of Prodrugs, and the evaluation of these in model systems for their therapeutic potential as anti-cancer agents in the clinic.

Tumor-Specific Monomethyl Auristatin E (MMAE) Prodrug Nanoparticles for Safe and Effective Chemotherapy

A prodrug is bioreversible medication that is specifically converted to the active drugs by enzymes overexpressed in the tumor microenvironment, which can considerably reduce the chemotherapy-induced side effects. However, prodrug strategies usually have low antitumor efficacy compared to free drugs by delayed drug release. This is because they need time to be activated by enzymatic cleavage and they also cannot be fully recovered to the active drugs. Therefore, highly potent anticancer drug should be considered to expect a sufficient antitumor efficacy. Herein, we propose tumor-specific monomethyl auristatin E (MMAE) prodrug nanoparticles for safe and effective chemotherapy. The cathepsin B-specific cleavable FRRG peptide and MMAE are chemically conjugated via one-step simple synthetic chemistry. The resulting FRRG-MMAE molecules form stable nanoparticles without any additional carrier materials by hydrophobic interaction-derived aggregations. The FRRG-MMAE nanoparticles efficiently accumulate within the tumor tissues owing to the enhanced permeability and retention (EPR) effect and inhibit the tubulin polymerization by releasing free MMAE in the cathepsin B-overexpressed tumor cells. In contrast, FRRG-MMAE nanoparticles maintain a non-toxic inactive state in the normal tissues owing to innately low cathepsin B expression, thereby reducing MMAE-related severe toxicity. Collectively, this study provides a promising approach for safe and effective chemotherapy via MMAE-based prodrug nanoparticles, which may open new avenues for advanced drug design for translational nanomedicine.

Preclinical development of carrier-free prodrug nanoparticles for enhanced antitumor therapeutic potential with less toxicity

Background

Nanomedicine has emerged as a promising strategy for cancer treatment. The most representative nanomedicine used in clinic is PEGylated liposomal doxorubicin DOXIL^®, which is first FDA-approved nanomedicine. However, several shortcomings, such as low drug loading capacity, low tumor targeting, difficulty in mass production and potential toxicity of carrier materials, have hindered the successful clinical translation of nanomedicines. In this study, we report a preclinical development process of the carrier-free prodrug nanoparticles designed as an alternative formulation to overcome limitations of conventional nanomedicines in the terms of technical- and industrial-aspects.

Results

The carrier-free prodrug nanoparticles (F68-FDOX) are prepared by self-assembly of cathepsin B-specific cleavable peptide (FRRG) and doxorubicin (DOX) conjugates without any additional carrier materials, and further stabilized with Pluronic F68, resulting in high drug loading (> 50%). The precise and concise structure allow mass production with easily controllable quality control (QC), and its lyophilized powder form has a great long-term storage stability at different temperatures (− 4, 37 and 60 °C). With high cathepsin B-specificity, F68-FDOX induce a potent cytotoxicity preferentially in cancer cells, whereas their cytotoxicity is greatly minimized in normal cells with innately low cathepsin B expression. In tumor models, F68-FDOX efficiently accumulates within tumor tissues owing to enhanced permeability and retention (EPR) effect and subsequently release toxic DOX molecules by cathepsin B-specific cleavage mechanism, showing a broad therapeutic spectrum with significant antitumor activity in three types of colon, breast and pancreatic cancers. Finally, the safety of F68-FDOX treatment is investigated after single-/multi-dosage into mice, showing greatly minimized DOX-related toxicity, compared to free DOX in normal mice.

Conclusions

Collectively, these results provide potential preclinical development process of an alternative approach, new formulation of carrier-free prodrug nanoparticles, for clinical translation of nanomedicines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01644-x.

Comparative study of cathepsin B-cleavable linkers for the optimal design of cathepsin B-specific doxorubicin prodrug nanoparticles for targeted cancer therapy

A carrier-free prodrug nanoparticle has emerged as a potential approach to cancer therapy. It plays a vital role in enhancing the tumor targeting and therapeutic efficacy of the anticancer agent at sites of intention wherein the prodrug nanoparticle is potentially activated. Herein, five derivatives of cathepsin B-cleavable prodrugs are synthesized via chemically conjugating different cathepsin B-cleavable peptides (Phe-Arg-Arg-Gly, Phe-Arg-Arg-Leu, Phe-Arg-Arg-Leu-Gly, Phe-Leu-Arg-Arg-Gly) to doxorubicin (DOX). The peptide-DOX prodrugs can spontaneously assemble into nanoparticles via their intermolecular hydrophobic and π-π stacking interactions. The resulting cathepsin B-cleavable prodrugs nanoparticles formed different nanoparticle structures according to the amphiphilicity and flexibility of different peptides and their particle stability and cellular uptake mechanism are carefully evaluated in vitro. Among five prodrug nanoparticles, the Phe-Arg-Arg-Leu-DOX (FRRL-DOX) nanoparticle was formed to a size of 167.5 ± 12.4 nm and stably maintains its nanoparticle structure in saline media for 3 days. The FRRL-DOX nanoparticle is well taken up by tumoral nuclei and effectively induces cancer cell death with minimal toxicity to normal cells. In addition, the FRRL-DOX nanoparticle shows 2.3-16.3-fold greater tumor-specific accumulation in vivo than other prodrug nanoparticles and free DOX. The therapeutic effect of FRRL-DOX is finally examined, demonstrating 2.1-fold better anticancer efficacy compared to that of free DOX. Notably, the FRRL-DOX nanoparticle does not exert serious toxicity in its repeated intravenous administration at a high dose of up to 10 mg/kg (equiv. to DOX). In conclusion, the peptide sequence for cathepsin B-cleavable prodrug nanoparticle is determined to be successfully optimized in a way of increasing its tumor selectivity and lowering toxicity to normal tissues.

Nanoparticles as Physically- and Biochemically-Tuned Drug Formulations for Cancers Therapy

Simple Summary

Conventional antitumor drugs have limitations, including poor water solubility and lack of targeting capability, with consequent non-specific distribution, systemic toxicity, and low therapeutic index. Nanotechnology promises to overcome these drawbacks by exploiting the physical properties of diverse nanocarriers that can be linked to moieties with binding selectivity for cancer cells. The use of nanoparticles as therapeutic formulations allows a targeted delivery and a slow, controlled release of the drug(s), making them tunable modules for applications in precision medicine. In addition, nanoparticles are also being developed as cancer vaccines, offering an opportunity to increase both cellular and humoral immunity, thus providing a new weapon to beat cancer.

Abstract

Malignant tumors originate from a combination of genetic alterations, which induce activation of oncogenes and inactivation of oncosuppressor genes, ultimately resulting in uncontrolled growth and neoplastic transformation. Chemotherapy prevents the abnormal proliferation of cancer cells, but it also affects the entire cellular network in the human body with heavy side effects. For this reason, the ultimate aim of cancer therapy remains to selectively kill cancer cells while sparing their normal counterparts. Nanoparticle formulations have the potential to achieve this aim by providing optimized drug delivery to a pathological site with minimal accumulation in healthy tissues. In this review, we will first describe the characteristics of recently developed nanoparticles and how their physical properties and targeting functionalization are exploited depending on their therapeutic payload, route of delivery, and tumor type. Second, we will analyze how nanoparticles can overcome multidrug resistance based on their ability to combine different therapies and targeting moieties within a single formulation. Finally, we will discuss how the implementation of these strategies has led to the generation of nanoparticle-based cancer vaccines as cutting-edge instruments for cancer immunotherapy.

How Did Conventional Nanoparticle-Mediated Photothermal Therapy Become "Hot" in Combination with Cancer Immunotherapy?

Simple Summary

Photothermal therapy (PTT) has become effective through the development of nanoparticle-based photoabsorbers with various functions, such as targeting properties, high light-to-heat conversion, and photostability. Conventional nanoparticle-mediated PTT has attained localized efficiency in cancer treatment by heat-induced apoptosis or necrosis of cancer cells. Currently, such treatment methods evolve into cancer immunotherapy through the induction of immunogenic cell death (ICD). Damage-associated molecular patterns from dead cells by nanoparticle-mediated PTT activate immune cells for systemic anti-cancer effect. In this review, we investigate various nanoparticle-based PTT and compare its methodology to clarify how it undergoes a transition from thermotherapy to immunotherapy.

Abstract

One of the promising cancer treatment methods is photothermal therapy (PTT), which has achieved good therapeutic efficiency through nanoparticle-based photoabsorbers. Because of the various functions of nanoparticles, such as targeting properties, high light-to-heat conversion, and photostability, nanoparticle-mediated PTT successfully induces photothermal damage in tumor tissues with minimal side effects on surrounding healthy tissues. The therapeutic efficacy of PTT originates from cell membrane disruption, protein denaturation, and DNA damage by light-induced heat, but these biological impacts only influence localized tumor areas. This conventional nanoparticle-mediated PTT still attracts attention as a novel cancer immunotherapy, because PTT causes immune responses against cancer. PTT-induced immunogenic cell death activates immune cells for systemic anti-cancer effect. Additionally, the excellent compatibility of PTT with other treatment methods (e.g., chemotherapy and immune checkpoint blockade therapy) reinforces the therapeutic efficacy of PTT as combined immunotherapy. In this review, we investigate various PTT agents of nanoparticles and compare their applications to reveal how nanoparticle-mediated PTT undergoes a transition from thermotherapy to immunotherapy.

Tumor-activated carrier-free prodrug nanoparticles for targeted cancer Immunotherapy: Preclinical evidence for safe and effective drug delivery

As immunogenic cell death (ICD) inducers initiating antitumor immune responses, certain chemotherapeutic drugs have shown considerable potential to reverse the immunosuppressive tumor microenvironment (ITM) into immune-responsive tumors. The application of these drugs in nanomedicine provides a more enhanced therapeutic index by improving unfavorable pharmacokinetic (PK) profiles and inefficient tumor targeting. However, the clinical translation of conventional nanoparticles is restricted by fundamental problems, such as risks of immunogenicity and potential toxicity by carrier materials, premature drug leakage in off-target sites during circulation, low drug loading contents, and complex structure and synthetic processes that hinder quality control (QC) and scale-up industrial production. To address these limitations, tumor-activated carrier-free prodrug nanoparticles (PDNPs), constructed only by the self-assembly of prodrugs without any additional carrier materials, have been widely investigated with distinct advantages for safe and more effective drug delivery. In addition, combination immunotherapy based on PDNPs with other diverse modalities has efficiently reversed the ITM to immune-responsive tumors, potentiating the response to immune checkpoint blockade (ICB) therapy. In this review, the trends and advances in PDNPs are outlined, and each self-assembly mechanism is discussed. In addition, various combination immunotherapies based on PDNPs are reviewed. Finally, a physical tumor microenvironment remodeling strategy to maximize the potential of PDNPs, and key considerations for clinical translation are highlighted.

Emerging Albumin-Binding Anticancer Drugs for Tumor-Targeted Drug Delivery: Current Understandings and Clinical Translation

Albumin has shown remarkable promise as a natural drug carrier by improving pharmacokinetic (PK) profiles of anticancer drugs for tumor-targeted delivery. The exogenous or endogenous albumin enhances the circulatory half-lives of anticancer drugs and passively target the tumors by the enhanced permeability and retention (EPR) effect. Thus, the albumin-based drug delivery leads to a potent antitumor efficacy in various preclinical models, and several candidates have been evaluated clinically. The most successful example is Abraxane, an exogenous human serum albumin (HSA)-bound paclitaxel formulation approved by the FDA and used to treat locally advanced or metastatic tumors. However, additional clinical translation of exogenous albumin formulations has not been approved to date because of their unexpectedly low delivery efficiency, which can increase the risk of systemic toxicity. To overcome these limitations, several prodrugs binding endogenous albumin covalently have been investigated owing to distinct advantages for a safe and more effective drug delivery. In this review, we give account of the different albumin-based drug delivery systems, from laboratory investigations to clinical applications, and their potential challenges, and the outlook for clinical translation is discussed. In addition, recent advances and progress of albumin-binding drugs to move more closely to the clinical settings are outlined.

Hyaluronic Acid Stabilized Doxorubicin Nano-Precipitations for Osteosarcoma Treatment

Doxorubicin (Dox) is a wide-spectrum drug to treat different kinds of cancers. However, in clinical practice, Dox usually showed untargeted distributions to the other organs, which can cause serious side effects, such as cardiotoxity. Herein, the formulation of Dox into nanoparticles is critical to enhance its distribution to tumors. Herein, we used polysaccharide, hyaluronic acid, to stabilize the Dox to form nano-precipitations (PD NPs) for the therapy of osteosarcoma. The PD NPs showed enhanced drug accumulation to tumor cells and realized better anticancer effects than free drugs.

Cathepsin B-Overexpressed Tumor Cell Activatable Albumin-Binding Doxorubicin Prodrug for Cancer-Targeted Therapy

Prodrugs are bioreversible medications that should undergo an enzymatic or chemical transformation in the tumor microenvironment to release active drugs, which improve cancer selectivity to reduce toxicities of anticancer drugs. However, such approaches have been challenged by poor therapeutic efficacy attributed to a short half-life and low tumor targeting. Herein, we propose cathepsin B-overexpressed tumor cell activatable albumin-binding doxorubicin prodrug, Al-ProD, that consists of a albumin-binding maleimide group, cathepsin B-cleavable peptide (FRRG), and doxorubicin. The Al-ProD binds to in situ albumin, and albumin-bound Al-ProD indicates high tumor accumulation with prolonged half-life, and selctively releases doxorubicin in cathepsin B-overexpressed tumor cells, inducing a potent antitumor efficacy. Concurrently, toxicity of Al-ProD toward normal tissues with innately low cathepsin B expression is significantly reduced by maintaining an inactive state, thereby increasing the safety of chemotherapy. This study offers a promising approach for effective and safe chemotherapy, which may open new avenues for drug design and translational medicine.

Intracellular Enzyme-Responsive Profluorophore and Prodrug Nanoparticles for Tumor-Specific Imaging and Precise Chemotherapy

Responsive drug delivery systems possess great potential in disease diagnosis and treatment. Herein, we develop an activatable prodrug and fluorescence imaging material by engineering the endogenous NAD(P)H:quinone oxidoreductase-1 (NQO1) responsive linker. The as-prepared nanomaterials possess the NQO1-switched drug release and fluorescence enablement, which realizes the tumor-specific chemotherapy and imaging in living mice. The enzyme-sensitive prodrug nanoparticles exhibit selectively potent anticancer performance to NQO1-positive cancer and ignorable off-target toxicity. This work provides an alternative strategy for constructing smart prodrug nanoplatforms with precision, selectivity, and practicability for advanced cancer imaging and therapy.

MUC14-Related ncRNA-mRNA Network in Breast Cancer

Abstract: Background Growing evidences have showed that mucins (MUCs) are linked to occurrence and progression of human cancers. However, a comprehensive study regarding the expression, diagnosis, prognosis and mechanism of MUCs in breast cancer remains absent. Methods: A series of in silico analyses were employed in this study. Results: After performing comprehensive analysis for MUCs, MUC14 was identified as the most potential regulator in breast cancer, with downregulated expression in both mRNA and protein levels and significant diagnostic and prognostic values in breast cancer. Mechanistic exploration revealed that a potential ncRNA-mRNA axis, involving LINC01128/LINC01140/SGMS1-AS1/LINC00667-miR-137/miR-429-BCL2, might be partially responsible for MUC14′s functions in breast cancer. Conclusions: Collectively, our study elucidated a key role of MUC14 in breast cancer and also provided some clues for explanation of the molecular action mechanism of MUC14 in breast cancer.

The safe and effective intraperitoneal chemotherapy with cathepsin B-specific doxorubicin prodrug nanoparticles in ovarian cancer with peritoneal carcinomatosis

Intraperitoneal (IP) chemotherapy has shown promising efficacy in ovarian cancer with peritoneal carcinomatosis (PC), but in vivo rapid clearance and severe toxicity of free anticancer drugs hinder the effective treatment. Herein, we propose the safe and effective IP chemotherapy with cathepsin B-specific doxorubicin prodrug nanoparticles (PNPs) in ovarian cancer with PC. The PNPs are prepared by self-assembling cathepsin B-specific cleavable peptide (FRRG) and doxorubicin (DOX) conjugates, which are further formulated with pluronic F68. The PNPs exhibit stable spherical structure and cytotoxic DOX is specifically released from PNPs via sequential enzymatic degradation by cathepsin B and intracellular proteases. The PNPs induce cytotoxicity in cathepsin B-overexpressing ovarian (SKOV-3 and HeyA8) and colon (MC38 and CT26) cancer cells, but not in cathepsin B-deficient normal cells in cultured condition. With enhanced cancer-specificity and in vivo residence time, IP injected PNPs efficiently accumulate within PC through two targeting mechanisms of direct penetration (circulation independent) and systemic blood vessel-associated accumulation (circulation dependent). As a result, IP chemotherapy with PNPs efficiently inhibit tumor progression with minimal side effects in peritoneal human ovarian tumor-bearing xenograft (POX) and patient derived xenograft (PDX) models. These results demonstrate that PNPs effectively inhibit progression of ovarian cancer with peritoneal carcinomatosis with minimal local and systemic toxicities by high cancer-specificity and favorable in vivo PK/PD profiles enhancing PC accumulation.

Engineering nanotheranostic strategies for liver cancer

The incidence and mortality of hepatocellular carcinoma have continued to increase over the last few years, and the medicine-based outlook of patients is poor. Given great ideas from the development of nanotechnology in medicine, especially the advantages in the treatments of liver cancer. Some engineering nanoparticles with active targeting, ligand modification, and passive targeting capacity achieve efficient drug delivery to tumor cells. In addition, the behavior of drug release is also applied to the drug loading nanosystem based on the tumor microenvironment. Considering clinical use of local treatment of liver cancer, in situ drug delivery of nanogels is also fully studied in orthotopic chemotherapy, radiotherapy, and ablation therapy. Furthermore, novel therapies including gene therapy, phototherapy, and immunotherapy are also applied as combined therapy for liver cancer. Engineering nonviral polymers to function as gene delivery vectors with increased efficiency and specificity, and strategies of co-delivery of therapeutic genes and drugs show great therapeutic effect against liver tumors, including drug-resistant tumors. Phototherapy is also applied in surgical procedures, chemotherapy, and immunotherapy. Combination strategies significantly enhance therapeutic effects and decrease side effects. Overall, the application of nanotechnology could bring a revolutionary change to the current treatment of liver cancer.

Targeted Delivery of Drugs and Genes Using Polymer Nanocarriers for Cancer Therapy

Cancer is one of the primary causes of worldwide human deaths. Most cancer patients receive chemotherapy and radiotherapy, but these treatments are usually only partially efficacious and lead to a variety of serious side effects. Therefore, it is necessary to develop new therapeutic strategies. The emergence of nanotechnology has had a profound impact on general clinical treatment. The application of nanotechnology has facilitated the development of nano-drug delivery systems (NDDSs) that are highly tumor selective and allow for the slow release of active anticancer drugs. In recent years, vehicles such as liposomes, dendrimers and polymer nanomaterials have been considered promising carriers for tumor-specific drug delivery, reducing toxicity and improving biocompatibility. Among them, polymer nanoparticles (NPs) are one of the most innovative methods of non-invasive drug delivery. Here, we review the application of polymer NPs in drug delivery, gene therapy, and early diagnostics for cancer therapy.

Rediscovery of nanoparticle-based therapeutics: boosting immunogenic cell death for potential application in cancer immunotherapy

Immunogenic cell death (ICD) occurring by chemical and physical stimuli has shown the potential to activate an adaptive immune response in the immune-competent living body through the release of danger-associated molecular patterns (DAMPs) into the tumor microenvironment (TME). However, limitations to the long-term immune responses and systemic toxicity of conventional ICD inducers have led to unsatisfactory therapeutic efficacy in ICD-based cancer immunotherapy. Until now, various nanoparticle-based ICD-inducers have been developed to induce an antitumor immune response without severe toxicity, and to efficiently elicit an anticancer immune response against target cancer cells. In this review, we introduce a recent advance in the designs and applications of nanoparticle-based therapeutics to elicit ICD for effective cancer immunotherapy. In particular, combination strategies of nanoparticle-based ICD inducers with typical theranostic modalities are introduced intensively. Subsequently, we discuss the expected challenges and future direction of nanoparticle-based ICD inducers to provide strategies for boosting ICD in cancer immunotherapy. These versatile designs and applications of nanoparticle-based therapeutics for ICD can provide advantages to improve the therapeutic efficacy of cancer immunotherapy.

Glutathione-responsive prodrug conjugates for image-guided combination in cancer therapy

Theranostic prodrug was highly desirable for precise diagnosis and anti-cancer therapy to decrease side effects. However, it is difficult to conjugate chemo-drug and molecular probe for combined therapy due to the complex pharmacokinetics of different molecules. Here, a novel anticancer theranostic prodrug (BTMP-SS-PTX) had been designed and synthesized by conjugating paclitaxel (PTX) with 2-(benzo[d]thiazol-2-yl)-4-methoxyphenol (BTMP) through a disulphide (-S-S-) linkage, which was redox-sensitive to the high concentration of glutathione in tumors. Upon activation with glutathione in weakly acid media, the BTMP-SS-PTX can be dissociated to release free PTX and visible BTMP, which realized the visual tracking of free drug. The cytotoxicity study demonstrated that soluble prodrug BTMP-SS-PTX displayed more outstanding anticancer activity in HepG2, MCF-7 and HeLa cells, lower toxicity to non-cancer cells (293 T) than free drugs. Furthermore, BTMP-SS-PTX was still able to induce apoptosis of HeLa cells and significantly inhibited tumor growth in HeLa-xenograft mouse model. On the basis of these findings, BTMP-SS-PTX could play a potential role in cancer diagnosis and therapy.

Oxidative stress in obesity-associated hepatocellular carcinoma: sources, signaling and therapeutic challenges

Obesity affects more than 650 million individuals worldwide and is a well-established risk factor for the development of hepatocellular carcinoma (HCC). Oxidative stress can be considered as a bona fide tumor promoter, contributing to the initiation and progression of liver cancer. Indeed, one of the key events involved in HCC progression is excessive levels of reactive oxygen species (ROS) resulting from the fatty acid influx and chronic inflammation. This review provides insights into the different intracellular sources of obesity-induced ROS and molecular mechanisms responsible for hepatic tumorigenesis. In addition, we highlight recent findings pointing to the role of the dysregulated activity of BCL-2 proteins and protein tyrosine phosphatases (PTPs) in the generation of hepatic oxidative stress and ROS-mediated dysfunctional signaling, respectively. Finally, we discuss the potential and challenges of novel nanotechnology strategies to prevent ROS formation in obesity-associated HCC.

Hierarchical drug release designed Au @PDA-PEG-MTX NPs for targeted delivery to breast cancer with combined photothermal-chemotherapy

Breast cancer (BC) is the most frequently diagnosed cancer with a low survival rate and one of the major causes of cancer-related death. Methotrexate (MTX) is an anti-tumor drug used in the treatment of BC. Poor dispersion in water and toxic side effects limit its clinical application. Gold nanoparticles (AuNPs), owing to their specific structures and unique biological and physiochemical properties, have emerged as potential vehicles for tumor targeting, bioimaging and cancer therapy. An innovative nano drug-loading system (Au @PDA-PEG-MTX NPs) was prepared for targeted treatment of BC. Au @PDA-PEG-MTX NPs under near infra-red region (NIR) irradiation showed effective photothermal therapy against MDA-MB-231 human BC cells growth in vitro by inducing apoptosis through triggering reactive oxygen species (ROS) overproduction and generating excessive heat. In vivo studies revealed deep penetration ability of Au @PDA-PEG-MTX NPs under NIR irradiation to find application in cancer-targeted fluorescence imaging, and exhibited effective photothermal therapy against BC xenograft growth by inducing apoptosis. Histopathological analysis, cellular uptake, cytotoxicity assay, and apoptosis experiments indicated that Au @PDA-PEG-MTX NPs possessed a good therapeutic effect with high biocompatibility and fewer side effects. This Au NPs drug-loading system achieved specific targeting of MTX to BC cells by surface functionalisation, fluorescence imaging under laser irradiation, combined photothermal-chemotherapy, and pH- and NIR- triggered hierarchical drug release.

Therapeutic Silencing of BCL-2 Using NK Cell-Derived Exosomes as a Novel Therapeutic Approach in Breast Cancer

Simple Summary

Overexpression of the antiapoptotic protein BCL-2 is correlated with estrogen receptor (ER) expression in breast cancer and plays an important role for disease pathophysiology. Here, we conceptualized a novel treatment strategy by targeting ER⁺ breast cancer with NK cell-derived exosomes used as a carrier for BCL-2 targeted siRNAs. With this new approach, we successfully enhanced killing ability of NK cell derived exosomes by silencing of BCL-2 overexpression.

Abstract

Overexpression of the anti-apoptotic protein BCL-2 is frequently observed in multiple malignancies, including about 85% of patients with estrogen receptor positive (ER⁺) breast cancer. Besides being studied as a prognostic marker, BCL-2 is investigated as a therapeutic target in ER⁺ breast cancer. Here, we introduce a new exosome-based strategy to target BCL-2 using genetically modified natural killer (NK) cells. The NK cell line NK92MI was lentivirally transduced to express and load BCL-2 siRNAs (siBCL-2) into exosomes (NKExos) and then evaluated for its potential to treat ER⁺ breast cancer. Transfected NK92MI cells produced substantial levels of BCL-2 siRNAs, without substantially affecting NK cell viability or effector function and led to loading of siBCL-2 in NKExos. Remarkably, targeting BCL-2 via siBCL-2 NKExos led to enhanced intrinsic apoptosis in breast cancer cells, without affecting non-malignant cells. Together, our prototypical results for BCL-2 in breast cancer provide proof of concept for a novel strategy to utilize NKExos as a natural delivery vector for siRNA targeting of oncogenes.

Cancer-activated doxorubicin prodrug nanoparticles induce preferential immune response with minimal doxorubicin-related toxicity

The effective chemotherapeutic drug, doxorubicin (DOX), elicits immunogenic cell death (ICD) and additional anticancer immune responses during chemotherapy. However, it also induces severe side effects and systemic immunosuppression, hampering its wide clinical application. Herein, we constructed cancer-activated DOX prodrug by conjugating the cathepsin B-cleavable peptide (Phe-Arg-Arg-Gly, FRRG) to a doxorubicin (DOX), resulting in FRRG-DOX that self-assembled into cancer-activated DOX prodrug nanoparticles (CAP-NPs). The resulting CAP-NPs were further stabilized with the FDA-approved compound, Pluronic F68. CAP-NPs formed stable prodrug nanoparticles and they were specifically cleaved to cytotoxic DOX molecules only in cathepsin B-overexpressing cancer cells, inducing a cancer cell-specific cytotoxicity. In particular, the CAP-NPs induced ICD through cathepsin B-cleavage mechanism only in targeted cancer cells in vitro. In colon tumor-bearing mice, selectively accumulated CAP-NPs at tumors enhanced antitumor immunity without DOX-related severe toxicity, inflammatory response and systemic immunosuppression. Moreover, cytotoxicity against immune cells infiltrated into tumor microenvironment was significantly reduced compared to free DOX, leading to increased response to checkpoint inhibitor immunotherapy. The combinatorial treatment of CAP-NPs with anti-PD-L1 exhibited high rate of complete tumor regression (50%) compared to free DOX with anti-PD-L1. Concurrently, DOX-related side effects were greatly reduced during chemoimmunotherapy. Collectively, our results suggest that cancer-activated DOX prodrug nanoparticles provide a promising approach to increase clinical benefit by inducing an immune response preferentially only to targeted cancer cells, not to normal cells and immune cells, and potentiates checkpoint inhibitor immunotherapy.

Emodin Interferes With AKT1-Mediated DNA Damage and Decreases Resistance of Breast Cancer Cells to Doxorubicin

Doxorubicin (DOX) is a cytotoxic drug used for the treatment of breast cancer (BC). However, the rapid emergence of resistance toward doxorubicin threatens its clinical application, thus the need for combination therapy. Here, we interrogate the role of Emodin, a chemical compound with tumor inhibitory properties, in the resistance of BC to Doxorubicin. We first evaluated the efficacy of Emodin in the treatment of BC cells. We then used γH2A to examine doxorubicin-induced DNA damage in BC cells, with or without Emodin. Data from CCK-8, flow cytometry, and tumor xenograft assays showed that Emodin suppresses the growth of BC cells. Further, we demonstrated that Emodin enhances γH2A levels in BC cells. Moreover, bioinformatics analysis and western blot assays indicated that Emodin down-regulates the AKT1 expression, and marginally decreases the levels of DNA damage proteins (XRCC1, PARP1, and RAD51) as well as increased p53 expression in BC cells. Taken together, our data demonstrates that Emodin affects cell proliferation, and DNA damage pathways in BC cells, thus increasing the sensitivity of BC cells to doxorubicin. Besides, we confirmed that Emodin confers sensitization of BC to doxorubicin through AKT1-mediated DNA.