A6 Peptide-Tagged Core-Disulfide-Cross-Linked Micelles for Targeted Delivery of Proteasome Inhibitor Carfilzomib to Multiple Myeloma In Vivo

Engineered IL-21-Expressing Nanovesicles for Co-Delivery of GOX and Ferrocene to Induce Synergistic Anti-Tumor Effects

Glucose oxidase (GOX)-induced starvation is a safe treatment for tumor. However, the non-specific targeting of GOX and the plasticity of tumor metabolism lead to toxic side effects and low tumor mortality. Thus, it is necessary to develop a synergistic strategy with high tumor targeting specificity to enhance the mortality of GOX. In this study, a genetically engineered CD44 targeting peptide (CP) and IL-21 fusion protein-displaying nanovesicles platform (mCP@IL21-Fc-GOX) are designed to efficiently encapsulate GOX and ferrocene (Fc). After reaching the tumor site, IL-21 can be precisely released and targeted to NK cells through the cleavage of MMP-2, thus achieving precise anti-tumor immunotherapy of IL-21. Second, the exposed CP enable mCP-Fc-GOX to be further targeted to tumor cells, completing the synergistic anti-cancer effects of starvation and chemodynamic therapy (CDT) triggered by GOX and Fc. In situ breast cancer models, the results show that mCP@IL21-Fc-GOX not only enhances NK and T cells aggregation in tumor tissue but also achieves precise nutrition deprivation and abundant reactive oxygen species production, thus significantly inhibits tumor growth based on the synergistic function of the immunotherapy, starvation and CDT. Therefore, this work provides a smart nanovesicle platform for achieving precise and safe synergistic anti-tumor therapy.

Breaking barriers: Smart vaccine platforms for cancer immunomodulation

Despite significant advancements in cancer treatment, current therapies often fail to completely eradicate malignant cells. This shortfall underscores the urgent need to explore alternative approaches such as cancer vaccines. Leveraging the immune system's natural ability to target and kill cancer cells holds great therapeutic potential. However, the development of cancer vaccines is hindered by several challenges, including low stability, inadequate immune response activation, and the immunosuppressive tumor microenvironment, which limit their efficacy. Recent progress in various fields, such as click chemistry, nanotechnology, exosome engineering, and neoantigen design, offer innovative solutions to these challenges. These achievements have led to the emergence of smart vaccine platforms (SVPs), which integrate protective carriers for messenger ribonucleic acid (mRNA) with functionalization strategies to optimize targeted delivery. Click chemistry further enhances SVP performance by improving the encapsulation of mRNA antigens and facilitating their precise delivery to target cells. This review highlights the latest developments in SVP technologies for cancer therapy, exploring both their opportunities and challenges in advancing these transformative approaches.

Bioresponsive Polymeric Nanoparticles: From Design, Targeted Therapy to Cancer Immunotherapy

Bioresponsive polymeric nanoparticles (NPs) that are capable of delivering and releasing therapeutics and biotherapeutics to target sites have attracted vivid interest in cancer therapy and immunotherapy. In contrast to enthusiastic evolution in the academic world, the clinical translation of these smart systems is scarce, partly due to concerns about safety, stability, complexity, and scalability. The moderate targetability, responsivity, and benefits are other concerns. In the past 17 years, we have devoted ourselves to exploring elegant strategies to address the above basic and translational problems by introducing diverse functional groups and/or targeting ligands to safe biomedical materials, such as biodegradable polymers and water-soluble polymers. This minimal modification is critical for further clinical translation. We have tailor-made various bioresponsive NPs including shell-sheddable and/or acid-sensitive biodegradable NPs, disulfide-cross-linked biodegradable micelles and polymersomes, and blood-brain barrier (BBB)-permeable NPs, to target different tumors. This perspective provides an overview of our work path toward targeted nanomedicines and personalized vaccines, which might inspire clinical translation and future research on cancer therapy.

Recent advances in targeted drug delivery systems for multiple myeloma

Despite significant therapeutic advances, multiple myeloma (MM) remains a challenging, incurable, hematological malignancy. The efficacy of traditional chemotherapy and currently available anti-MM agents is in part limited by their adverse effects, which restrict their therapeutic potential. Nanotherapeutics is an emerging field of cancer therapy that can overcome the biological and chemical barriers of existing anticancer drugs. This review presents an overview of recent advancements in nanoparticle- and immunotherapy-based drug delivery systems for MM treatment. It further delves into the targeting strategies, mechanism of controlled drug release, and challenges associated with the development of drug delivery systems for the treatment of MM.

Recent advancements in nanomedicine as a revolutionary approach to treating multiple myeloma

Multiple myeloma, the second most common hematological malignancy, remains incurable with a 5-year survival rate of approximately 50 % and recurrence rates near 100 %, despite significant attempts to develop effective medicines. Therefore, there is a pressing demand in the medical field for innovative and more efficient treatments for MM. Currently, the standard approach for treating MM involves administering high-dose chemotherapy, which frequently correlates with improved results; however, one major limiting factor is the significant side effects of these medications. Furthermore, the strategies used to deliver medications to tumors limit their efficacy, whether by rapid clearance from circulation or an insufficient concentration in cancer cells. Cancer treatment has shifted from cytotoxic, nonspecific chemotherapy regimens to molecularly targeted, rationally developed drugs with improved efficacy and fewer side effects. Nanomedicines may provide an effective alternative way to avoid these limits by delivering drugs into the complicated bone marrow microenvironment and efficiently reaching myeloma cells. Putting drugs into nanoparticles can make their pharmacokinetic and pharmacodynamic profiles much better. This can increase the drug's effectiveness in tumors, extend its time in circulation in the blood, and lower its off-target toxicity. In this review, we introduce several criteria for the rational design of nanomedicine to achieve the best anti-tumoral therapeutic results. Next, we discuss recent advances in nanomedicine for MM therapy.

Targeted Delivery Strategies for Multiple Myeloma and Their Adverse Drug Reactions

Currently, multiple myeloma (MM) is a prevalent hematopoietic system malignancy, known for its insidious onset and unfavorable prognosis. Recently developed chemotherapy drugs for MM have exhibited promising therapeutic outcomes. Nevertheless, to overcome the shortcomings of traditional clinical drug treatment, such as off-target effects, multiple drug resistance, and systemic toxicity, targeted drug delivery systems are optimizing the conventional pharmaceuticals for precise delivery to designated sites at controlled rates, striving for maximal efficacy and safety, presenting a promising approach for MM treatment. This review will delve into the outstanding performance of antibody-drug conjugates, peptide-drug conjugates, aptamer-drug conjugates, and nanocarrier drug delivery systems in preclinical studies or clinical trials for MM and monitor their adverse reactions during treatment.

Rational peptide design for targeting cancer cell invasion

Cell invasion is an important process in cancer progression and recurrence. Invasion and implantation of cancer cells from their original place to other tissues, by disabling vital organs, challenges the treatment of cancer patients. Given the importance of the matter, many molecular treatments have been developed to inhibit cancer cell invasion. Because of their low production cost and ease of production, peptides are valuable therapeutic molecules for inhibiting cancer cell invasion. In recent years, advances in the field of computational biology have facilitated the design of anti-cancer peptides. In our investigation, using computational biology approaches such as evolutionary analysis, residue scanning, protein-peptide interaction analysis, molecular dynamics, and free energy analysis, our team designed a peptide library with about 100 000 candidates based on A6 (acetyl-KPSSPPEE-amino) sequence which is an anti-invasion peptide. During computational studies, two of the designed peptides that give the highest scores and showed the greatest sequence similarity to A6 were entered into the experimental analysis workflow for further analysis. In experimental analysis steps, the anti-metastatic potency and other therapeutic effects of designed peptides were evaluated using MTT assay, RT-qPCR, zymography analysis, and invasion assay. Our study disclosed that the IK1 (acetyl-RPSFPPEE-amino) peptide, like A6, has great potency to inhibit the invasion of cancer cells.

Antibody-Mediated Nanodrug of Proteasome Inhibitor Carfilzomib Boosts the Treatment of Multiple Myeloma

Multiple myeloma (MM) is the second most common hematological malignancy. For relapsed and refractory MM, a proteasome inhibitor, carfilzomib (CFZ), has become one of the few clinical options. CFZ suffers, nevertheless, metabolic instability and poor bioavailability and may induce severe cardiovascular and renal adverse events. Here, we report that daratumumab (Dar)-decorated polypeptide micelles (Dar-PMs) mediate the targeted delivery of CFZ to CD38-positive MM, effectively boosting its anti-MM efficacy. CFZ-loaded Dar-PMs (Dar-PMs-CFZ) exhibited an average diameter of ca. 80 nm and Dar density-dependent cell endocytosis and anti-MM activity, in which over 6-fold greater inhibitory effect to LP-1 and MM.1S MM cells than nontargeted PMs-CFZ control was achieved at a Dar density of 3.2 (Dar3.2-PMs-CFZ). Interestingly, Dar3.2-PMs-CFZ markedly enhanced the growth inhibition of orthotopic LP-1 MM in mice and significantly extended the median survival time compared with PMs-CFZ and free CFZ (95 days vs 60 and 54 days, respectively). In line with its high MM targetability and anti-MM efficacy, Dar3.2-PMs-CFZ revealed little toxic effects and effectively prevented osteolytic lesions. The antibody-targeted nanodelivery of a proteasome inhibitor appears to be an appealing strategy to treat multiple myeloma.

Ubiquitin-proteasome system as a target for anticancer treatment-an update

As the ubiquitin-proteasome system (UPS) regulates almost every biological process, the dysregulation or aberrant expression of the UPS components causes many pathological disorders, including cancers. To find a novel target for anticancer therapy, the UPS has been an active area of research since the FDA's first approval of a proteasome inhibitor bortezomib in 2003 for treating multiple myeloma (MM). Here, we summarize newly described UPS components, including E3 ubiquitin ligases, deubiquitinases (DUBs), and immunoproteasome, whose malfunction leads to tumorigenesis and whose inhibitors have been investigated in clinical trials as anticancer therapy since 2020. We explain the mechanism and effects of several inhibitors in depth to better comprehend the advantages of targeting UPS components for cancer treatment. In addition, we describe attempts to overcome resistance and limited efficacy of some launched proteasome inhibitors, as well as an emerging PROTAC-based tool targeting UPS components for anticancer therapy.

Anti-BCMA surface engineered biomimetic photothermal nanomissile enhances multiple myeloma cell apoptosis and overcomes the disturbance of NF-κB signaling in vivo

Conventional chemotherapy for multiple myeloma (MM) faces the challenges of a low complete remission rate and transformation to recurrence/refractory. The current MM first-line clinical drug Bortezomib (BTZ) faces the problem of enhanced tolerance and nonnegligible side effects. B cell maturation antigen (BCMA), for its important engagement in tumor signaling pathways and novel therapy technologies such as Chimeric antigen receptor T-Cell immunotherapy (CAR-T) and Antibody Drug Conjugate (ADC), has been identified as an ideal target and attracted attention in anti-MM therapy. Emerging nanotechnology provided feasible methods for drug delivery and new therapeutic strategies such as photothermal therapy (PTT). Herein, we developed a BCMA-Targeting biomimetic photothermal nanomissile BTZ@BPQDs@EM @anti-BCMA (BBE@anti-BCMA) by integration of BTZ, black phosphorus quantum dots (BPQDs), Erythrocyte membrane (EM) and BCMA antibody (anti-BCMA). We hypothesized that this engineered nanomissile could attack tumor cells in triple ways and achieve effective treatment of MM. Consequently, the intrinsic biomimetic nature of EM and the active targeting property of anti-BCMA enhanced the accumulation of therapeutic agents in the tumor site. Besides, owing to the decrease in BCMA abundance, the potential apoptosis-inducing ability was revealed. With the support of BPQDs' photothermal effect, Cleaved-Caspase-3 and Bax signal increased significantly, and the expression of Bcl-2 was inhibited. Furthermore, the synergistic photothermal/chemo therapy can effectively inhibit tumor growth and reverse the disorder of NF-κB in vivo. Importantly, this biomimetic nanodrug delivery system and antibody induced synergistic therapeutic strategy efficiently killed MM cells with ignorable systemic toxicity, which is a promising method for the future anticancer treatment of hematological malignancies in clinics.

Mesoscopic Simulations of Diselenide-Containing Crosslinked Doxorubicin-Loaded Micelles and Their Tumor Microenvironment Responsive Release Behaviors

There is currently limited research on the structure-property relationship of reduction stimuli-responsive polymeric crosslinked micelles using mesoscopic simulations. Herein, dissipative particle dynamics (DPD) simulations were used to simulate the self-assembly process of the blank non-crosslinked micelle, the structure and doxorubicin (DOX) distribution of diselenide crosslinked micelle with different crosslinker contents (CCs) based on the nearest-neighbor bonding principle. The results revealed that the formation of a three-layer spherical micelle and the loaded DOX mainly distributed in the polycaprolactone (PCL) core and hydroxyethyl methacrylate (HEMA) mesosphere. The larger the dosage of DOX, the more DOX encapsulated, but the encapsulation of DOX in the hydrophobic domain would reach saturation when the dosage increased to 6.0 %. In micelles with lower CCs or crosslinking levels (CLs), DOX entered the middle layer and the inner core faster. Then, based on the nearest media-bead bond breaking principle and subsequently DPD simulation, the effects of different CCs on the micelle structure and DOX release properties were investigated. Low CC could cause fast drug release. With the increase of CCs, the micelle showed a slower DOX release trend. The multilayer crosslinked network system also affected the DOX release rate. Hence, this work can provide some mesoscale guidance for the structural design and structure-property relationship of stimuli-responsive reversible crosslinked micelles for drug delivery.

In vitro and ex vivo anti-myeloma effects of nanocomposite As4S4/ZnS/Fe3O4

Nanoparticles in medicine can integrate actively targeted imaging agents and drug delivery vehicles, and combining multiple types of therapeutics in a single particle has numerous advantages, especially in multiple myeloma. MM is an incurable hematological disorder characterized by clonal proliferation of plasma cells in the bone marrow. In this study, we evaluated the anti-myeloma activity of 3 nanocomposites (3NPs): As₄S₄/ZnS/Fe₃O₄ (1:4:1), As₄S₄/ZnS/Fe₃O₄ with folic acid (FA), and As₄S₄/ZnS/Fe₃O₄ with FA and albumin with reduced survival MM cell lines and primary MM samples by each of 3NP. Cytotoxic effects of 3NPs were associated with caspase- and mitochondria-dependent apoptosis induction and reduced c-Myc expression. Modulation of cell cycle regulators, such as p-ATM/ATM and p-ATR/ATR, and increases in p-Chk2, cyclin B1, and histones were accompanied by G₂/M arrest triggered by 3NPs. In addition, 3NPs activated several myeloma-related signaling, including JNK1/2/3, ERK1/2 and mTOR. To overcome BM microenvironment-mediated drug resistance, nanocomposites retained its anti-MM activity in the presence of stroma. 3NPs significantly decreased the stem cell-like side population in MM cells, even in the context of stroma. We observed strong synergistic effects of 3NPs combined with lenalidomide, pomalidomide, or melphalan, suggesting the potential of these combinations for future clinical studies.

Pathogenesis and treatment of multiple myeloma

Multiple myeloma (MM) is the second‐ranking malignancy in hematological tumors. The pathogenesis of MM is complex with high heterogeneity, and the development of the disease is a multistep process. Chromosomal translocations, aneuploidy, genetic mutations, and epigenetic aberrations are essential in disease initiation and progression. The correlation between MM cells and the bone marrow microenvironment is associated with the survival, progression, migration, and drug resistance of MM cells. In recent decades, there has been a significant change in the paradigm for the management of MM. With the development of proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, chimeric antigen receptor T‐cell therapies, and novel agents, the survival of MM patients has been significantly improved. In addition, nanotechnology acts as both a nanocarrier and a treatment tool for MM. The properties and responsive conditions of nanomedicine can be tailored to reach different goals. Nanomedicine with a precise targeting property has offered great potential for drug delivery and assisted in tumor immunotherapy. In this review, we summarize the pathogenesis and current treatment options of MM, then overview recent advances in nanomedicine‐based systems, aiming to provide more insights into the treatment of MM.

CD44-targeting hydrophobic phosphorylated gemcitabine prodrug nanotherapeutics augment lung cancer therapy

Gemcitabine (GEM) is among the most used chemotherapies for advanced malignancies including non-small cell lung cancer. The clinical efficacy of GEM is, however, downplayed by its poor bioavailability, short half-life, drug resistance, and dose-limiting toxicities (e.g. myelosuppression). In spite of many approaches exploited to improve the efficacy and safety of GEM, limited success was achieved. The short A6 peptide (sequence: Ac-KPSSPPEE-NH₂) is clinically validated for specific binding to CD44 on metastatic tumors. Here, we designed a robust and CD44-specific GEM nanotherapeutics by encapsulating hydrophobic phosphorylated gemcitabine prodrug (HPG) into the core of A6 peptide-functionalized disulfide-crosslinked micelles (A6-mHPG), which exhibited reduction-triggered HPG release and specific targetability to CD44 overexpressing tumor cells. Interestingly, A6 greatly enhanced the internalization and inhibitory activity of micellar HPG (mHPG) in CD44 positive A549 cells, and increased its accumulation in A549 cancerous lung, leading to potent repression of orthotopic tumor growth, depleted toxicity, and marked survival benefits compared to free HPG and mHPG (median survival time: 59 days versus 30 and 45 days, respectively). The targeted delivery of gemcitabine prodrug with disulfide-crosslinked biodegradable micelles appears to be a highly appealing strategy to boost gemcitabine therapy for advance tumors. STATEMENT OF SIGNIFICANCE: Gemcitabine (GEM) though widely used in clinics for treating advanced tumors is associated with poor bioavailability, short half-life and dose-limiting toxicities. Development of clinically translatable GEM formulations to improve its anti-tumor efficacy and safety is of great interest. Here, we report on CD44-targeting GEM nanotherapeutics obtained by encapsulating hydrophobic phosphorylated GEM prodrug (HPG), a single isomer of NUC-1031, into A6 peptide-functionalized disulfide-crosslinked micelles (A6-mHPG). A6-mHPG demonstrates stability against degradation, enhanced internalization and inhibition toward CD44⁺ cells, and increased accumulation in A549 lung tumor xenografts, leading to potent repression of orthotopic tumor growth, depleted toxicity and marked survival benefits. The targeted delivery of GEM prodrug using A6-mHPG is a highly appealing strategy to GEM cancer therapy.

A review of controlled release from cyclodextrins: release methods, release systems and application

The controlled release of guest molecules from cyclodextrin (CD) inclusion complexes is very important for specific industrial applications in foods, medicine, cosmetics, textiles, agriculture, environmental protection, and chemical materials. The term "controlled release" encompasses several related methods, including those referred to as immediate release, sustained release and targeted release. Many different CD-based controlled release systems are currently used in practical applications. CD inclusion complexes, CD coupling, supramolecular hydrogels, and supramolecular micelles are among the most common. This review systematically introduces the principles and applications of CD-based controlled release systems, providing a theoretical basis for improving the bioavailability of effective substances and broadening their range of application.

Small, Smart, and LDLR-Specific Micelles Augment Sorafenib Therapy of Glioblastoma

Targeted molecular therapy, for example, with sorafenib (SF) is considered as a new and potent strategy for glioblastoma (GBM) that remains hard to treat today. Several clinical trials with SF, as monotherapy or combination therapy with current treatments, have not met the clinical endpoints, likely as a result of the blood-brain barrier (BBB) and inferior GBM delivery. Here, we designed and explored small, smart, and LDLR-specific micelles to load SF (LDLR-mSF) and to improve SF therapy of GBM by enhancing BBB penetration, GBM accumulation, and cell uptake. LDLR-mSF with 2.5% ApoE peptide functionality based on poly(ethylene glycol)-poly(ε-caprolactone-co-dithiolane trimethylene carbonate)-mefenamate exhibited nearly quantitative SF loading, small size (24 nm), high colloidal stability, and glutathione-activated SF release. The in vitro and in vivo studies certified that LDLR-mSF greatly enhanced BBB permeability and U-87 MG cell uptake and caused 10.6- and 12.9-fold stronger anti-GBM activity and 6.0- and 2.5-fold higher GBM accumulation compared with free SF and non-LDLR mSF controls, respectively. The treatment of an orthotopic human GBM tumor model revealed that LDLR-mSF at a safe dosage of 15 mg of SF/kg significantly retarded tumor progression and improved the survival rate by inducing tumor cell apoptosis and inhibiting tumor angiogenesis. These small, smart, and LDLR-specific micelles provide a potential solution to enhance targeted molecular therapy of GBM.

Polymeric nanomedicines targeting hematological malignancies

Hematological malignancies (HMs) typically persisting in the blood, lymphoma, and/or bone marrow invalidate surgery and local treatments clinically used for solid tumors. The presence and drug resistance nature of cancer stem cells (CSCs) further lends HMs hard to cure. The development of new treatments like molecular targeted drugs and antibodies has improved the clinical outcomes for HMs but only to a certain extent, due to issues of low bioavailability, moderate response, occurrence of drug resistance, and/or dose-limiting toxicities. In the past years, polymeric nanomedicines targeting HMs including refractory and relapsed lymphoma, leukemia and multiple myeloma have emerged as a promising chemotherapeutic approach that is shown capable of overcoming drug resistance, delivering drugs not only to cancer cells but also CSCs, and increasing therapeutic index by lessening drug-associated adverse effects. In addition, polymeric nanomedicines have shown to potentiate next-generation anticancer modalities such as therapeutic proteins and nucleic acids in effectively treating HMs. In this review, we highlight recent advance in targeted polymeric nanoformulations that are coated with varying ligands (e.g. cancer cell membrane proteins, antibodies, transferrin, hyaluronic acid, aptamer, peptide, and folate) and loaded with different therapeutic agents (e.g. chemotherapeutics, molecular targeted drugs, therapeutic antibodies, nucleic acid drugs, and apoptotic proteins) for directing to distinct targets (e.g. CD19, CD20, CD22, CD30, CD38, CD44, CD64, CXCR, FLT3, VLA-4, and bone marrow microenvironment) in HMs. The advantages and potential challenges of different designs are discussed.

Reduction-Responsive Anticancer Nanodrug Using a Full Poly(ethylene glycol) Carrier

Poly(ethylene glycol) (PEG) is applied extensively in biomedical fields because of its nontoxic, nonimmunogenic, and protein resistance properties. However, the strong hydrophilicity of PEG prevents it from self-assembling into an amphiphilic micelle in water, making it a challenge to fabricate a full-PEG carrier to deliver hydrophobic anticancer drugs. Herein, a paclitaxel (PTX)-loaded nanodrug was readily prepared through self-assembly of PTX and an amphiphilic PEG derivative, which was synthesized via melt polycondensation of two PEG diols (i.e., PEG₂₀₀ and PEG_10k) and mercaptosuccinic acid. The full PEG component endows the nanocarrier with good biocompatibility. Furthermore, because of the core cross-linked structure via the oxidation of mercapto groups, the nanodrug can be selectively disassociated under an intratumor reductive microenvironment through the reduction of disulfide bonds to release the loaded PTX and kill the cancer cells while maintaining high stability under the extratumor physiological condition. Additionally, it was confirmed that the nanodrug not only prolongs the biocirculation time of PTX but also possesses excellent in vivo antitumor efficacy while avoiding side effects of free PTX, for example, liver damage, which is promising for delivering clinical hydrophobic drugs to treat a variety of malignant tumors.

Harnessing Endogenous Stimuli for Responsive Materials in Theranostics

Materials that respond to endogenous stimuli are being leveraged to enhance spatiotemporal control in a range of biomedical applications from drug delivery to diagnostic tools. The design of materials that undergo morphological or chemical changes in response to specific biological cues or pathologies will be an important area of research for improving efficacies of existing therapies and imaging agents, while also being promising for developing personalized theranostic systems. Internal stimuli-responsive systems can be engineered across length scales from nanometers to macroscopic and can respond to endogenous signals such as enzymes, pH, glucose, ATP, hypoxia, redox signals, and nucleic acids by incorporating synthetic bio-inspired moieties or natural building blocks. This Review will summarize response mechanisms and fabrication strategies used in internal stimuli-responsive materials with a focus on drug delivery and imaging for a broad range of pathologies, including cancer, diabetes, vascular disorders, inflammation, and microbial infections. We will also discuss observed challenges, future research directions, and clinical translation aspects of these responsive materials.

Recent Advancements in Stimuli Responsive Drug Delivery Platforms for Active and Passive Cancer Targeting

The tumor-specific targeting of chemotherapeutic agents for specific necrosis of cancer cells without affecting the normal cells poses a great challenge for researchers and scientists. Though extensive research has been carried out to investigate chemotherapy-based targeted drug delivery, the identification of the most promising strategy capable of bypassing non-specific cytotoxicity is still a major concern. Recent advancements in the arena of onco-targeted therapies have enabled safe and effective tumor-specific localization through stimuli-responsive drug delivery systems. Owing to their promising characteristic features, stimuli-responsive drug delivery platforms have revolutionized the chemotherapy-based treatments with added benefits of enhanced bioavailability and selective cytotoxicity of cancer cells compared to the conventional modalities. The insensitivity of stimuli-responsive drug delivery platforms when exposed to normal cells prevents the release of cytotoxic drugs into the normal cells and therefore alleviates the off-target events associated with chemotherapy. Contrastingly, they showed amplified sensitivity and triggered release of chemotherapeutic payload when internalized into the tumor microenvironment causing maximum cytotoxic responses and the induction of cancer cell necrosis. This review focuses on the physical stimuli-responsive drug delivery systems and chemical stimuli-responsive drug delivery systems for triggered cancer chemotherapy through active and/or passive targeting. Moreover, the review also provided a brief insight into the molecular dynamic simulations associated with stimuli-based tumor targeting.

Stimuli-Responsive Aliphatic Polycarbonate Nanocarriers for Tumor-Targeted Drug Delivery

Nanoparticles based on amphiphilic copolymers with tunable physicochemical properties can be used to encapsulate delicate pharmaceutics while at the same time improving their solubility, stability, pharmacokinetic properties, reducing immune surveillance, or achieving tumor-targeting ability. Those nanocarriers based on biodegradable aliphatic polycarbonates are a particularly promising platform for drug delivery due to flexibility in the design and synthesis of appropriate monomers and copolymers. Current studies in this field focus on the design and the synthesis of new effective carriers of hydrophobic drugs and their release in a controlled manner by exogenous or endogenous factors in tumor-specific regions. Reactive groups present in aliphatic carbonate copolymers, undergo a reaction under the action of a stimulus: e.g., acidic hydrolysis, oxidation, reduction, etc. leading to changes in the morphology of nanoparticles. This allows the release of the drug in a highly controlled manner and induces a desired therapeutic outcome without damaging healthy tissues. The presented review summarizes the current advances in chemistry and methods for designing stimuli-responsive nanocarriers based on aliphatic polycarbonates for controlled drug delivery.

Recent Advances in Nanotherapeutics for Multiple Myeloma

Simple Summary

Nanotherapeutics are useful tools to improve the deliverability of drugs, especially anti-cancer drugs that need to target specific cells. Several approaches have been studied for multiple myeloma, considering that immune cells are not easy to target with the available drugs. These pharmacological agents are administered in various combinations using Thalidomide (or Lenalidomide, Pomalidomide), corticosteroids (Dexamethasone), proteasome inhibitors (Bortezomib, Carfilzomib, Ixazomib), deacetylase inhibitors (Panobinostat), and monoclonal antibodies (Elotuzumab, Daratumumab). As all drugs these agents might have serious side effects and in addition, the reliance on stochastic events to deliver drugs to tumors reduces their effectiveness either through rapid clearance from blood or inadequate concentration in cancer cells. To address these issues liposomes, micelles, polymeric nanoparticles, inorganic nanoparticles, and carbon-based nanomaterials have been successfully tested in vivo and can be considered as useful tools to improve delivery of active pharmaceuticals that show poor bioavailability or poor internalization into myeloma cells.

Abstract

Anticancer therapies cannot be included in a one-size-fits-all scenario; it is imperative to adapt therapies to the tumor molecular profile and most importantly to develop target-specific therapeutics. Nanotherapeutics can combine molecular imaging with molecular therapy in order to provide the maximum benefit to patients in terms of disease prevention, identification, and treatment. Nanotechnology applied to therapy provides numerous advantages in diagnostics and in drug delivery, especially for those malignant cells that are difficult to target or for drugs with poor bioavailability, such as those used for multiple myeloma (MM). This review summarizes the recent advances in the development of nanoparticle-based systems for the treatment of MM, taking into account the methods used for their functionalization, biocompatibility, and anticancer activity.