CD44-Specific A6 Short Peptide Boosts Targetability and Anticancer Efficacy of Polymersomal Epirubicin to Orthotopic Human Multiple Myeloma

Acetyl-lysine human serum albumin nanoparticles activate CD44 receptors, with preferential uptake by cancer stem cells, leading to tumor eradication

CD44 receptors in cancer stem cells (CSCs) are a key biomarker associated with cancer recurrence, progression, and metastasis. Acetylation is a post-translational modification used to regulate protein function at the end of protein synthesis. In this study, we found that acetylated human serum albumin (Ac-HSA) acts an uptake ligand on CD44 receptors. This promising finding motivated us to develop an Ac-HSA-based nanocarrier for cancer chemotherapy. By conjugating maleimide-polylactic acid (MAL-PLA) with Ac-HSA, the resulting amphiphile formed nanoparticles (Ac-HSA-PLA NPs) which were shown to rapidly enter CD44+ cancer cells and cancer stem cells via CD44-mediated endocytosis. This contrasts with the comparatively slow uptake of CD44 antibodies. Abraxane®, an approved human serum albumin (HSA) nanoparticle formulation of paclitaxel (PTX) demonstrates that PTX may be delivered by HSA nanoparticles. However, Abraxane® is not clinically superior to solvent-based PTX formulations. In a CD44+ tumor model, PTX-loaded Ac-HSA-PLA NPs outperformed Abraxane®, achieving complete tumor elimination without recurrence, two months post-treatment, while Abraxane treated tumors continued to grow (tumor volume increased five fold). The Ac-HSA-PLA (PTX) NPs also demonstrated minimal systemic toxicity, suggesting that Ac-HSA could be a promising alternative for targeted cancer therapy in CD44-expressing cancers.

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.

Polymersome-based nanomotors: preparation, motion control, and biomedical applications

Polymersome-based nanomotors represent a cutting-edge development in nanomedicine, merging the unique vesicular properties of polymersomes with the active propulsion capabilities of synthetic nanomotors. As a vesicular structure enclosed by a bilayer membrane, polymersomes can encapsulate both hydrophilic and hydrophobic cargoes. In addition, their physical-chemical properties such as size, morphology, and surface chemistry are highly tunable, which makes them ideal for various biomedical applications. The integration of motility into polymersomes enables them to actively navigate biological environments and overcome physiological barriers, offering significant advantages over passive delivery platforms. Recent breakthroughs in fabrication techniques and motion control strategies, including chemically, enzymatically, and externally driven propulsion, have expanded their potential for drug delivery, biosensing, and therapeutic interventions. Despite these advancements, key challenges remain in optimizing propulsion efficiency, biocompatibility, and in vivo stability to translate these systems into clinical applications. In this perspective, we discuss recent advancements in the preparation and motion control strategies of polymersome-based nanomotors, as well as their biomedical-related applications. The molecular design, fabrication approaches, and nanomedicine-related utilities of polymersome-based nanomotors are highlighted, to envisage the future research directions and further development of these systems into effective, precise, and smart nanomedicines capable of addressing critical biomedical challenges.

Design and synthesis of isatin derivative payloaded peptide-drug conjugate as tubulin inhibitor against colorectal cancer

A series of isatin derivatives which could inhibit colorectal cancer (CRC) were synthesized. Among those compounds, 5B exhibited good inhibitory activity of CRC through the inhibition of tubulin expression, inducing apoptosis, and causing G2/M phase cell cycle arrest pathway, which suggested that 5B could be a potential tubulin inhibitor. Based on that, a novel peptide-drug conjugate (PDC), which employed the CRC cells related receptor CD44 ligand peptide A6 coupling to 5B to accomplish A6-5B. The in vitro and in vivo studies showed that A6-5B could significantly inhibit the tumor growth and metastasis in CRC cells. Mechanistic studies revealed that both 5B and A6-5B exert their antitumor effects by inhibiting tubulin, demonstrating that 5B might play a payload role and A6 could act as a targeting moiety for selective drug delivery to tumor cells.

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.

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.

A peptide-salinomycin conjugate with a bystander effect reduces the stemness characteristics of ovarian cancer cells and enhances drug sensitivity

Salinomycin (Sal) has attracted considerable attention in the field of tumor treatment, especially for its inhibitory effect on cancer stem cells (CSCs) and drug-resistant tumor cells. However, its solubility and targeting specificity pose significant challenges to its pharmaceutical development. Sal-A6, a novel peptide-drug conjugate (PDC), was formed by linking the peptide A6 targeting the CSC marker CD44 with Sal using a specific linker. This conjugation markedly enhances the physicochemical properties of Sal and compared to Sal, Sal-A6 demonstrated a significantly increased activity against ovarian cancer. Furthermore, Sal-A6, employing a disulfide bond as a linker, exhibited bystander killing effect. Moreover, it induces substantial cytotoxic effect on both cancer stem cells and drug-resistant cells in addition to enhance chemosensitivity of resistant ovarian cancer cells. In summary, the results indicated that Sal-A6, a novel PDC derived from Sal, has potential therapeutic applications in the treatment of ovarian cancer and drug-resistant patients. Additionally, this discovery offers insights for developing PDC-type drugs using Sal as a foundation.

Surface-engineered erythrocyte membrane-camouflage fluorescent bioprobe for precision ovarian cancer surgery

PURPOSE

Fluorescence imaging-guided surgery has been used in oncology. However, for tiny tumors, the current imaging probes are still difficult to achieve high-contrast imaging, leading to incomplete resection. In this study, we achieved precise surgical resection of tiny metastatic cancers by constructing an engineering erythrocyte membrane-camouflaged bioprobe (AR-M@HMSN@P).

METHODS

AR-M@HMSN@P combined the properties of aggregation-induced emission luminogens (AIEgens) named PF3-PPh3 (P), with functional erythrocyte membrane modified by a modular peptide (AR). Interestingly, AR was composed of an asymmetric tripodal pentapeptide scaffold (GGKGG) with three appended modulars: KPSSPPEE (A6) peptide, RRRR (R4) peptide and cholesterol. To verify the specificity of the probe in vitro, SKOV3 cells with overexpression of CD44 were used as the positive group, and HLF cells with low expression of CD44 were devoted as the control group. The AR-M@HMSN@P fluorescence imaging was utilized to provide surgical guidance for the removal of micro-metastatic lesions.

RESULTS

In vivo, the clearance of AR-M@HMSN@P by the immune system was reduced due to the natural properties inherited from erythrocytes. Meanwhile, the A6 peptide on AR-M@HMSN@P was able to specifically target CD44 on ovarian cancer cells, and the electrostatic attraction between the R4 peptide and the cell membrane enhanced the firmness of this targeting. Benefiting from these multiple effects, AR-M@HMSN@P achieved ultra-precise tumor imaging with a signal-to-noise ratio (SNR) of 15.2, making it possible to surgical resection of tumors < 1 mm by imaging guidance.

CONCLUSION

We have successfully designed an engineered fluorescent imaging bioprobe (AR-M@HMSN@P), which can target CD44-overexpressing ovarian cancers for precise imaging and guide the resection of minor tumors. Notably, this work holds significant promise for developing biomimetic probes for clinical imaging-guided precision cancer surgery by exploiting their externally specified functional modifications.

A Biomimetic Autophagosomes-Based Nanovaccine Boosts Anticancer Immunity

Personalized cancer vaccines based on tumor cell lysates offer promise for cancer immunotherapy yet fail to elicit a robust therapeutic effect due to the weak immunogenicity of tumor antigens. Autophagosomes, obtained from pleural effusions and ascites of cancer patients, have been identified as abundant reservoirs of tumor neoantigens that exhibit heightened immunogenicity. However, their potential as personalized cancer vaccines have been constrained by suboptimal lymphatic-targeting performances and challenges in antigen-presenting cell endocytosis. Here,a reinforced biomimetic autophagosome-based (BAPs) nanovaccine generated by precisely amalgamating autophagosome-derived neoantigens and two types of adjuvants capable of targeting lymph nodes is developed to potently elicit antitumor immunity. The redox-responsive BAPs facilitate cytosolic vaccine opening within antigen-presenting cells, thereby exposing adjuvants and antigens to stimulate a strong immune response. BAPs evoke broad-spectrum T-cell responses, culminating in the effective eradication of 71.4% of established tumors. Notably, BAPs vaccination triggers enduring T-cell responses that confer robust protection, with 100% of mice shielded against tumor rechallenge and a significant reduction in tumor incidence by 87.5%. Furthermore, BAPs synergize with checkpoint blockade therapy to inhibit tumor growth in the poorly immunogenic breast cancer model. The biomimetic approach presents a powerful nanovaccine formula with high versatility for personalized cancer immunotherapy.

Redefining drug therapy: innovative approaches using catalytic compartments

INTRODUCTION

Rapid excretion of drug derivatives often results in short drug half-lives, necessitating frequent administrations. Catalytic compartments, also known as nano- and microreactors, offer a solution by providing confined environments for in situ production of therapeutic agents. Inspired by natural compartments, polymer-based catalytic compartments have been developed to improve reaction efficiency and enable site-specific therapeutic applications.

AREAS COVERED

Polymer-based compartments provide stability, permeability control, and responsiveness to stimuli, making them ideal for generating localized compounds/signals. These sophisticated systems, engineered to carry active compounds and enable selective molecular release, represent a significant advancement in pharmaceutical research. They mimic cellular functions, creating controlled catalytic environments for bio-relevant processes. This review explores the latest advancements in synthetic catalytic compartments, focusing on design approaches, building blocks, active molecules, and key bio-applications.

EXPERT OPINION

Catalytic compartments hold transformative potential in precision medicine by improving therapeutic outcomes through precise, on-site production of therapeutic agents. While promising, challenges like scalable manufacturing, biodegradability, and regulatory hurdles must be addressed to realize their full potential. Addressing these will be crucial for their successful application in healthcare.

ROS-responsive nanoparticle delivery of ferroptosis inhibitor prodrug to facilitate mesenchymal stem cell-mediated spinal cord injury repair

Spinal cord injury (SCI) is a traumatic condition that results in impaired motor and sensory function. Ferroptosis is one of the main causes of neural cell death and loss of neurological function in the spinal cord, and ferroptosis inhibitors are effective in reducing inflammation and repairing SCI. Although human umbilical cord mesenchymal stem cells (Huc-MSCs) can ameliorate inflammatory microenvironments and promote neural regeneration in SCI, their efficacy is greatly limited by the local microenvironment after SCI. Therefore, in this study, we constructed a drug-release nanoparticle system with synergistic Huc-MSCs and ferroptosis inhibitor, in which we anchored Huc-MSCs by a Tz-A6 peptide based on the CD44-targeting sequence, and combined with the reactive oxygen species (ROS)-responsive drug nanocarrier mPEG-b-Lys-BECI-TCO at the other end for SCI repair. Meanwhile, we also modified the classic ferroptosis inhibitor Ferrostatin-1 (Fer-1) and synthesized a new prodrug Feborastatin-1 (Feb-1). The results showed that this treatment regimen significantly inhibited the ferroptosis and inflammatory response after SCI, and promoted the recovery of neurological function in rats with SCI. This study developed a combination therapy for the treatment of SCI and also provides a new strategy for the construction of a drug-coordinated cell therapy system.

CXCR4-Mediated Codelivery of FLT3 and BCL-2 Inhibitors for Enhanced Targeted Combination Therapy of FLT3-ITD Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is often associated with poor prognosis and survival. Small molecule inhibitors, though widening the treatment landscape, have limited monotherapy efficacy. The combination therapy, however, shows suboptimal clinical outcomes due to low bioavailability, overlapping systemic toxicity and drug resistance. Here, we report that CXCR4-mediated codelivery of the BCL-2 inhibitor venetoclax (VEN) and the FLT3 inhibitor sorafenib (SOR) via T22 peptide-tagged disulfide cross-linked polymeric micelles (TM) achieves synergistic treatment of FLT3-ITD AML. TM-VS with a VEN/SOR weight ratio of 1/4 and T22 peptide density of 20% exhibited an extraordinary inhibitory effect on CXCR4-overexpressing MV4-11 AML cells. TM-VS at a VEN/SOR dosage of 2.5/10 mg/kg remarkably reduced leukemia burden, prolonged mouse survival, and impeded bone loss in orthotopic MV4-11-bearing mice, outperforming the nontargeted M-VS and oral administration of free VEN/SOR. CXCR4-mediated codelivery of BCL-2 and FLT3 inhibitors has emerged as a prospective clinical treatment for FLT3-ITD AML.

Mesoporous polydopamine Targeting CDK4/6 Inhibitor toward Brilliant Synergistic Immunotherapy of Breast Cancer

Immunotherapy utilizing anti-PD-L1 blockade has achieved dramatic success in clinical breast cancer management but is often hampered by the limited immune response. Increasing evidence shows that immunogenic cell death (ICD) recently arises as a promising strategy for enlarging tumor immunogenicity and eliciting systemic anti-tumor immunity effectively. However, developing simple but versatile, highly efficient but low-toxic, biosafe, and clinically available transformed ICD inducers remains a huge demand and is highly desirable. Herein, a multifunctional ICD inducer is purposefully developed A6-MPDA@PAL by integrating photothermal therapy (PTT) nanoplatforms mesoporous polydopamine (MPDA), CDK4/6 inhibitor palbociclib (PAL), and CD44-specific targeting A6 peptide in a simple way for augmenting the immune antitumor efficacy of anti-PD-L1 therapy. Remarkably, the light-inducible nanoplatforms exhibit multiple favorable therapeutic features ensuring a superior and biosafe PTT/chemotherapy efficacy. Together with stronger accumulative ICD induction, single administration of A6-MPDA@PAL can trigger robust systemic antitumor immunity and abscopal effect with the assistance of anti-PD-L1 blockade by fascinating the intratumoral infiltration of T lymphocytes and reversing the immunosuppressive tumor microenvironment simultaneously, therapy achieving brilliant synergistic immunotherapy with effective tumor ablation. This study presents a simple and smart ICD inducer opening up attractive clinical possibilities for reinforcing the anti-PD-L1 therapy against breast cancer.

Informed by Cancer Stem Cells of Solid Tumors: Advances in Treatments Targeting Tumor-Promoting Factors and Pathways

Cancer stem cells (CSCs) represent a subpopulation within tumors that promote cancer progression, metastasis, and recurrence due to their self-renewal capacity and resistance to conventional therapies. CSC-specific markers and signaling pathways highly active in CSCs have emerged as a promising strategy for improving patient outcomes. This review provides a comprehensive overview of the therapeutic targets associated with CSCs of solid tumors across various cancer types, including key molecular markers aldehyde dehydrogenases, CD44, epithelial cellular adhesion molecule, and CD133 and signaling pathways such as Wnt/β-catenin, Notch, and Sonic Hedgehog. We discuss a wide array of therapeutic modalities ranging from targeted antibodies, small molecule inhibitors, and near-infrared photoimmunotherapy to advanced genetic approaches like RNA interference, CRISPR/Cas9 technology, aptamers, antisense oligonucleotides, chimeric antigen receptor (CAR) T cells, CAR natural killer cells, bispecific T cell engagers, immunotoxins, drug-antibody conjugates, therapeutic peptides, and dendritic cell vaccines. This review spans developments from preclinical investigations to ongoing clinical trials, highlighting the innovative targeting strategies that have been informed by CSC-associated pathways and molecules to overcome therapeutic resistance. We aim to provide insights into the potential of these therapies to revolutionize cancer treatment, underscoring the critical need for a multi-faceted approach in the battle against cancer. This comprehensive analysis demonstrates how advances made in the CSC field have informed significant developments in novel targeted therapeutic approaches, with the ultimate goal of achieving more effective and durable responses in cancer patients.

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.

A dissipative particle dynamics simulation of controlled loading and responsive release of theranostic agents from reversible crosslinked triblock copolymer vesicles

To control the transport stability and release efficiency of loaded theranostic drugs in triblock copolymer carriers, the reversible crosslinking ability is of great significance. A molecular level exploration of such a function is needed to extend existing stabilizing and responsive dissociation mechanisms of carriers. Here, dissipative particle dynamics simulations were used to first demonstrate the formation of triblock copolymer vesicular carriers. Chemical crosslinking was used to strengthen the structural stability of the vesicle shell to avoid drug leakage. Reversible decrosslinking along with dissociation of the vesicle and release of loaded drugs were then explored. The structural, energetic and dynamical properties of the system were discussed at the molecular level. The regulation mechanism of drug release patterns was revealed by systematically exploring the effect of intra and intermolecular repulsive interactions. The results indicate that the chemical crosslinking of copolymers enhanced the compactness of the vesicle shell with a strengthened microstructure, increased binding energy, and limited chain migration, thus achieving more stable delivery of drugs. In terms of drug release, we clarified how the pairwise interactions of beads in the solution system affect the responsive dissociation of the vesicle and associated release patterns (speed and amount) of drugs. More efficient delivery and smart release of theranostic drugs are achieved using such reversible crosslinked triblock copolymer vesicles.

CD44-specific short peptide A6 boosts cellular uptake and anticancer efficacy of PEGylated liposomal doxorubicin in vitro and in vivo

Although liposomes have improved patient safety and the pharmacokinetic profile of free drugs, their therapeutic efficacy has only shown marginal improvement. The incorporation of active-targeted ligands to enhance cellular uptake has shown promise in preclinical studies. However, no active-targeted liposomes have successfully translated into clinical use thus far. This study aimed to evaluate the targeting ability and antitumor efficiency of A6, a specific short peptide (KPSSPPEE) when incorporated into PEGylated liposomal doxorubicin (PLD). The results revealed significantly enhanced cellular uptake. The cytotoxicity of the formulations was determined by 3 h and 6 h incubation of formulations with cells, followed by 48 h incubation to evaluate the targeted ability of the formulations and the results indicated the higher cytotoxicity of A6-PLD (IC50 of 7.52 µg/mL after 6 h incubation) in the CD44 overexpressing C26 cell line compared to non-targeted PLD (IC50 of 15.02 µg/mL after 6 h incubation). However, CD44-negative NIH-3T3 cells exhibited similar uptake and in vitro cytotoxicity for both A6-PLD (IC50 of 38.05 µg/mL) and PLD (IC50 of 34.87 µg/mL). In animal studies, A6-PLD demonstrated significantly higher tumor localization of doxorubicin (Dox) (~ 8 and 15 µg Dox/g tumor for 24 and 48 after injection) compared to PLD (~ 6 and 8 µg Dox/g tumor for 24 and 48 after injection), resulting in effective inhibition of tumor growth. The median survival time (MST) for Dextrose 5% was 10, PLD was 14 and A6-PLD was 22 days. In conclusion, A6-PLD, a simple and effective targeted liposome formulation, exhibits high potential for clinical translation. Its improved targetability and antitumor efficacy make it a promising candidate for future clinical applications.

Polymersome Membrane Engineering with Active Targeting or Controlled Permeability for Responsive Drug Delivery

Polymersomes have been extensively investigated for drug delivery as nanocarriers for two decades due to a series of advantages including high stability under physiological conditions, simultaneous encapsulation of hydrophilic and hydrophobic drugs inside inner cavities and membranes, respectively, and facile adjustment of membrane and surface properties, as well as controlled drug release through incorporation of stimuli-responsive components. Despite these features, polymersome nanocarriers frequently suffer from nontargeting delivery and poor membrane permeability. In recent years, polymersomes have been functionalized for more efficient drug delivery. The surface shells were explored to be modified with diverse active targeting groups to improve disease-targeting delivery. The membrane permeability of the polymersomes was adjusted by incorporation of the stimuli-responsive components for smart controlled transportation of the encapsulated drugs. Therefore, being the polymersome-biointerface, tailorable properties can be introduced by its carefully modulated engineering. This review elaborates on the role of polymersome membranes as a platform to incorporate versatile features. First, we discuss how surface functionalization facilitates the directional journey to the targeting sites toward specific diseases, cells, or intracellular organelles via active targeting. Moreover, recent advances in the past decade related to membrane permeability to control drug release are also summarized. We finally discuss future development to promote polymersomes as in vivo drug delivery nanocarriers.

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.

Transferrin-guided intelligent nanovesicles augment the targetability and potency of clinical PLK1 inhibitor to acute myeloid leukemia

Acute myeloid leukemia (AML) remains a most lethal hematological malignancy, partly because of its slow development of targeted therapies compared with other cancers. PLK1 inhibitor, volasertib (Vol), is among the few molecular targeted drugs granted breakthrough therapy status for AML; however, its fast clearance and dose-limiting toxicity greatly restrain its clinical benefits. Here, we report that transferrin-guided polymersomes (TPs) markedly augment the targetability, potency and safety of Vol to AML. Vol-loaded TPs (TPVol) with 4% transferrin exhibited best cellular uptake, effective down-regulation of p-PLK1, p-PTEN and p-AKT and superior apoptotic activity to free Vol in MV-4-11 leukemic cells. Intravenous injection of TPVol gave 6-fold higher AUC than free Vol and notable accumulation in AML-residing bone marrow. The efficacy studies in orthotopic MV-4-11 leukemic model demonstrated that TPVol significantly reduced leukemic cell proportions in periphery blood, bone marrow, liver and spleen, effectively enhanced mouse survival rate, and impeded bone loss. This transferrin-guided nano-delivery of molecular targeted drugs appears to be an interesting strategy towards the development of novel treatments for AML.

Peptidyl Virus-Like Nanovesicles as Reconfigurable "Trojan Horse" for Targeted siRNA Delivery and Synergistic Inhibition of Cancer Cells

The self-assembly of peptidyl virus-like nanovesicles (pVLNs) composed of highly ordered peptide bilayer membranes that encapsulate the small interfering RNA (siRNA) is reported. The targeting and enzyme-responsive sequences on the bilayer's surface allow the pVLNs to enter cancer cells with high efficiency and control the release of genetic drugs in response to the subcellular environment. By transforming its structure in response to the highly expressed enzyme matrix metalloproteinase 7 (MMP-7) in cancer cells, it helps the siRNA escape from the lysosomes, resulting in a final silencing efficiency of 92%. Moreover, the pVLNs can serve as reconfigurable "Trojan horse" by transforming into membranes triggered by the MMP-7 and disrupting the cytoplasmic structure, thereby achieving synergistic anticancer effects and 96% cancer cell mortality with little damage to normal cells. The pVLNs benefit from their biocompatibility, targeting, and enzyme responsiveness, making them a promising platform for gene therapy and anticancer therapy.

Anti-tumor effects of P-LPK-CPT, a peptide-camptothecin conjugate, in colorectal cancer

To explore highly selective targeting molecules of colorectal cancer (CRC) is a challenge. We previously identified a twelve-amino acid peptide (LPKTVSSDMSLN, namely P-LPK) by phage display technique which may specifically binds to CRC cells. Here we show that P-LPK selectively bind to a panel of human CRC cell lines and CRC tissues. In vivo, Gallium-68 (⁶⁸Ga) labeled P-LPK exhibits selective accumulation at tumor sites. Then, we designed a peptide-conjugated drug comprising P-LPK and camptothecin (CPT) (namely P-LPK-CPT), and found P-LPK-CPT significantly inhibits tumor growth with fewer side effects in vitro and in vivo. Furthermore, through co-immunoprecipitation and molecular docking experiment, the glutamine transporter solute carrier 1 family member 5 (SLC1A5) was identified as the possible target of P-LPK. The binding ability of P-LPK and SLC1A5 is verified by surface plasmon resonance and immunofluorescence. Taken together, P-LPK-CPT is highly effective for CRC and deserves further development as a promising anti-tumor therapeutic for CRC, especially SLC1A5-high expression type.

A peptide that specifically targets amino acid transporter SLC1A5 in colorectal cancer cells is identified and conjugated with camptothecin to show selective cytotoxicity to colorectal cancer cells in preclinical models.

Self-assembled peptide-paclitaxel nanoparticles for enhancing therapeutic efficacy in colorectal cancer

Chemotherapy is one of the main treatments for colorectal cancer, but systemic toxicity severely limits its clinical use. Packaging hydrophobic chemotherapeutic drugs in targeted nanoparticles greatly improve their efficacy and reduce side effects. We previously identified a novel colorectal cancer specific binding peptide P-LPK (LPKTVSSDMSLN) from phage display peptide library. Here we designed a self-assembled paclitaxel (PTX)-loaded nanoparticle (LPK-PTX NPs). LPK-PTX NPs displayed a superior intracellular internalization and improved tumor cytotoxicity in vitro. Cy5.5-labeled LPK-PTX NPs showed much higher tumor accumulation in colorectal cancer-bearing mice. Furthermore, LPK-PTX NPs exhibit enhanced antitumor activity and decreased systemic toxicity in colorectal cancer patient-derived xenografts (PDX) model. The excellent in vitro and in vivo antitumor efficacy proves the improved targeting drug delivery, suggesting that peptide P-LPK has potential to provide a novel approach for enhanced drug delivery with negligible systemic toxicity.

IL-11Rα-targeted nanostrategy empowers chemotherapy of relapsed and patient-derived osteosarcoma

Osteosarcoma (OS) is a rare but frequently lethal bone malignancy in children and adolescents. The adjuvant chemotherapy with doxorubicin (Dox) and cisplatin remains a mainstream clinical practice though it affords only limited clinical benefits due to low tumor deposition, dose-limiting toxicity and high rate of relapse/metastasis. Here, taking advantage of high IL-11Rα expression in the OS patients, we installed IL-11Rα specific peptide (sequence: CGRRAGGSC) onto redox-responsive polymersomes encapsulating Dox (IL11-PDox) to boost the specificity and anti-OS efficacy of chemotherapy. Of note, IL-11Rα peptide at a density of 20% greatly augmented the internalization, apoptotic activity, and migration inhibition of Dox in IL-11Rα-overexpressing 143B OS cells. The active targeting effect of IL-11-PDox was supported in orthotopic and relapsed 143B OS models, as shown by striking repression of tumor growth and lung metastasis and substantial survival benefits over free Dox control. We further verified that IL11-PDox could effectively inhibit patient-derived OS xenografts. IL-11Rα-targeted nanodelivery of chemotherapeutics provides a potential therapeutic strategy for advanced osteosarcoma.

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.

ApoE-mediated systemic nanodelivery of granzyme B and CpG for enhanced glioma immunotherapy

The response of malignant glioma to immunotherapy remains gloomy due to its discrete immunological environment and poor brain penetration of immunotherapeutic agents. Here, we disclose that ApoE peptide-mediated systemic nanodelivery of granzyme B (GrB) and CpG ODN co-stimulates enhanced immunotherapy of murine malignant LCPN glioma model. ApoE peptide-functionalized polymersomes encapsulating GrB (ApoE-PS-GrB) could effectively penetrate the blood-brain barrier-mimicking endothelial cell monolayer in vitro and further be taken up by LCPN cells, inducing strong immunogenic cell death (ICD). The co-administration of ApoE-PS-GrB and ApoE-PS-CpG in orthotopic LCPN glioma-bearing mice co-stimulated cytokine production, maturation of dendritic cells (DCs), infiltration of cytotoxic T lymphocytes (CTLs) while reduction of regulatory T lymphocytes (T_reg) and M2 phenotype macrophages in the tumor microenvironment, leading to greatly delayed tumor progression and significantly prolonged survival time compared with all controls. The ApoE-mediated systemic nanodelivery of GrB and CpG ODN opens a new pathway for potent immunotherapy of malignant glioma.

Redox-responsive self-assembled polymeric nanoprodrug for delivery of gemcitabine in B-cell lymphoma therapy

Gemcitabine, as a standard and classic strategy for B-cell lymphoma in the clinic, is limited by its poor pharmacodynamics. Although stimuli-responsive polymeric nanodelivery systems have been widely investigated in the past decade, issues such as complicated procedures, low loading capacity, and uncontrollable release kinetics still hinder their clinical translation. In view of the above considerations, we attempt to construct hyperbranched polyprodrug micelles with considerable drug loading via simple procedures and make use of the particularity of the tumor microenvironment to ensure that the micelles are "inactivated" in normal tissues and "activated" in the tumor microenvironment. Hence, in this work, a redox-responsive polymeric gemcitabine-prodrug (GEM-S-S-PEG) was one-pot synthesized via facile esterification and acylation. The self-assembled subsize (< 100 nm) GEM-S-S-PEG (GSP NPs) with considerable loading capacity (≈ 24.6%) exhibited on-demand and accurate control of gemcitabine release under a simulated tumor microenvironment and thus significantly induced the apoptosis of B-cell lymphoma in vitro. Moreover, in the A20 tumor xenograft murine model, GSP NPs efficiently decreased the expansion of tumor tissues with minimal systemic toxicity. In summary, these redox-responsive and self-assembling GSP NPs with a facile one-pot synthesis procedure may hold great potency in clinical translation for enhanced chemotherapy of B-cell lymphoma. STATEMENT OF SIGNIFICANCE: A redox-responsive polymeric gemcitabine-prodrug (GEM-S-S-PEG) was one-pot synthesized via facile esterification and acylation. The self-assembled subsize (< 100 nm) GEM-S-S-PEG (GSP NPs) exhibited significant tumor therapeutic effects in vitro and in vivo. The polyprodrug GEM-S-S-PEG prepared in this study shows the great potential of redox-responsive nanodrugs for antitumor activity, which provides a reference value for the optimization of the design of functional polyprodrugs.

Inverting glucuronidation of hymecromone in situ by catalytic nanocompartments

Glucuronidation is a metabolic pathway that inactivates many drugs including hymecromone. Adverse effects of glucuronide metabolites include a reduction of half-life circulation times and rapid elimination from the body. Herein, we developed synthetic catalytic nanocompartments able to cleave the glucuronide moiety from the metabolized form of hymecromone in order to convert it to the active drug. By shielding enzymes from their surroundings, catalytic nanocompartments favor prolonged activity and lower immunogenicity as key aspects to improve the therapeutic solution. The catalytic nanocompartments (CNCs) consist of self-assembled poly(dimethylsiloxane)-block-poly(2-methyl-2-oxazoline) diblock copolymer polymersomes encapsulating β-glucuronidase. Insertion of melittin in the synthetic membrane of these polymersomes provided pores for the diffusion of the hydrophilic hymecromone-glucuronide conjugate to the compartment inside where the encapsulated β-glucuronidase catalyzed its conversion to hymecromone. Our system successfully produced hymecromone from its glucuronide conjugate in both phosphate buffered solution and cell culture medium. CNCs were non-cytotoxic when incubated with HepG2 cells. After being taken up by cells, CNCs produced the drug in situ over 24 hours. Such catalytic platforms, which locally revert a drug metabolite into its active form, open new avenues in the design of therapeutics that aim at prolonging the residence time of a drug.

Macrophage-Targeted Hydroxychloroquine Nanotherapeutics for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is an autoimmune disease with unclear pathogenesis. Hydroxychloroquine (HCQ), despite its moderate anti-RA efficacy, is among the few clinical drugs used for RA therapy. Macrophages reportedly play a vital role in RA. Here, we designed and explored macrophage-targeted HCQ nanotherapeutics based on mannose-functionalized polymersomes (MP-HCQ) for RA therapy. Notably, MP-HCQ exhibited favorable properties of less than 50 nm size, glutathione-accelerated HCQ release, and M1 phenotype macrophage (M1M) targetability, leading to repolarization of macrophages to anti-inflammatory M2 phenotype (M2M), reduced secretion of pro-inflammatory cytokines (IL-6), and upregulation of anti-inflammatory cytokines (IL-10). The therapeutic studies in the zymosan-induced RA (ZIA) mouse model showed marked accumulation of MP-HCQ in the inflammation sites, ameliorated symptoms of RA joints, significantly reduced IL-6, TNF-α, and IL-1β, and increased IL-10 and TGF-β compared with free HCQ. The analyses of RA joints disclosed greatly amplified M2M and declined mature DCs, CD4⁺ T cells, and CD8⁺ T cells. In accordance, MP-HCQ significantly reduced the damage of RA joints, cartilages, and bones compared to free HCQ and non-targeted controls. Macrophage-targeted HCQ nanotherapeutics therefore appears as a highly potent treatment for RA.

Strategies for active tumor targeting-an update

A complete cure for cancer is still the holy grail for scientists. The existing treatment of cancer is primarily focused on surgery, radiation and conventional chemotherapy. However, chemotherapeutic agents also affect healthy tissues or organs due to a lack of specificity. While passive targeting is studied for anticancer drugs focused on the enhanced permeability and retention effect, it failed to achieve drug accumulation at the tumor site and desired therapeutic efficacy. This review presents an outline of the current significant targets for active tumor drug delivery systems and provides insight into the direction of active tumor-targeting strategies. For this purpose, a systematic understanding of the physiological factors, tumor microenvironment and its components, overexpressed receptor and associated proteins are covered here. We focused on angiogenesis mediated targeting, receptor-mediated targeting and peptide targeting. This active targeting along with integration with nano delivery systems helps in achieving specific action, thus reducing the associated adverse effects to healthy tissues. Although the tumor-targeting methods and possibilities explored so far seem revolutionary in cancer treatment, in-depth clinical studies data is required for its commercial translation.

Daratumumab Immunopolymersome-Enabled Safe and CD38-Targeted Chemotherapy and Depletion of Multiple Myeloma

Multiple myeloma (MM) is a second ranking hematological malignancy. Despite the fast advancement of new treatments such as bortezormib and daratumumab, MM patients remain incurable and tend to eventually become relapsed and drug-resistant. Development of novel therapies capable of depleting MM cells is strongly needed. Here, daratumumab immunopolymersomes carrying vincristine sulfate (Dar-IPs-VCR) are reported for safe and high-efficacy CD38-targeted chemotherapy and depletion of orthotopic MM in vivo. Dar-IPs-VCR made by postmodification via strain-promoted click reaction holds tailored antibody density (2.2, 4.4 to 8.7 Dar per IPs), superb stability, small size (43-49 nm), efficacious VCR loading, and glutathione-responsive VCR release. Dar_4.4 -IPs-VCR induces exceptional anti-MM activity with an IC₅₀ of 76 × 10^-12 m to CD38-positive LP-1 MM cells, 12- and 20-fold enhancement over nontargeted Ps-VCR and free VCR controls, respectively. Intriguingly, mice bearing orthotopic LP-1-Luc MM following four cycles of i.v. administration of Dar_4.4 -IPs-VCR at 0.25 mg VCR equiv. kg^-1 reveal complete depletion of LP-1-Luc cells, superior survival rate to all controls, and no body weight loss. The bone and histological analyses indicate bare bone and organ damage. Dar-IPs-VCR appears as a safe and targeted treatment for CD38-overexpressed hematological malignancies.

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.

Biodegradable Polymersomes with Structure Inherent Fluorescence and Targeting Capacity for Enhanced Photo-Dynamic Therapy

Biodegradable nanostructures displaying aggregation-induced emission (AIE) are desirable from a biomedical point of view, due to the advantageous features of loading capacity, emission brightness, and fluorescence stability. Herein, biodegradable polymers comprising poly (ethylene glycol)-block-poly(caprolactone-gradient-trimethylene carbonate) (PEG-P(CLgTMC)), with tetraphenylethylene pyridinium-TMC (PAIE) side chains have been developed, which self-assembled into well-defined polymersomes. The resultant AIEgenic polymersomes are intrinsically fluorescent delivery vehicles. The presence of the pyridinium moiety endows the polymersomes with mitochondrial targeting ability, which improves the efficiency of co-encapsulated photosensitizers and improves therapeutic index against cancer cells both in vitro and in vivo. This contribution showcases the ability to engineer AIEgenic polymersomes with structure inherent fluorescence and targeting capacity for enhanced photodynamic therapy.

Systemic administration of polymersomal oncolytic peptide LTX-315 combining with CpG adjuvant and anti-PD-1 antibody boosts immunotherapy of melanoma

Oncolytic peptide LTX-315 while showing clinical promise in treating solid tumors is limited to intratumoral administration, which is not applicable for inaccessible or metastatic tumors. The cationic and amphipathic nature of oncolytic peptides engenders formidable challenges to developing systems for their systemic delivery. Here, we describe cRGD-functionalized chimaeric polymersomes (cRGD-CPs) as a robust systemic delivery vehicle for LTX-315, which in combination with CpG adjuvant and anti-PD-1 boost immunotherapy of malignant B16F10 melanoma in mice. cRGD-CPs containing 14.9 wt% LTX-315 (cRGD-CPs-L) exhibited a size of 53 nm, excellent serum stability, and strong and selective killing of B16F10 cells (versus L929 fibroblasts) in vitro, which provoked similar immunogenic effects to free LTX-315 as revealed by release of danger-associated molecular pattern molecules. The systemic administration of cRGD-CPs-L gave a notable tumor accumulation of 4.8% ID/g and significant retardation of tumor growth. More interestingly, the treatment of B16F10 tumor-bearing mice was further boosted by co-administration of polymersomal CpG and anti-PD-1 antibody, in which two out of seven mice were cured as a result of strong immune response and long-term immune memory protection. The immunotherapeutic effect was evidenced by secretion of IL-6, IFN-γ and TNF-α, tumor infiltration of CD8⁺ CTLs and T_h, and induction of T_EM and T_CM in spleen. This study opens a new avenue to oncolytic peptides, which enables durable immunotherapy of tumors via systemic administration.

Facile fabrication of robust, hyaluronic acid-surfaced and disulfide-crosslinked PLGA nanoparticles for tumor-targeted and reduction-triggered release of docetaxel

It is highly tempting to develop high-efficacy targeted nanotherapeutics based on FDA approved polymers like PLGA. Herein, we describe facile fabrication of robust, hyaluronic acid-surfaced and disulfide-crosslinked star-PLGA nanoparticles (HA-sPLGA XNPs) for targeted and reduction-triggered release of docetaxel (DTX), achieving markedly enhanced treatment of A549 lung tumor in vivo. HA-sPLGA XNPs carrying 5.2 wt.% DTX (DTX-HA-sPLGA XNPs) had a size of 105.5 ± 0.5 nm and great stability while almost completely released DTX under 10 mM glutathione. Confocal and flow cytometry experiments revealed fast cellular uptake of HA-sPLGA XNPs by CD44-overexpressing A549 cells. DTX-HA-sPLGA XNPs held much higher potency to A549 cells than DTX-loaded HA-surfaced and non-crosslinked star-PLGA nanoparticles (DTX-HA-sPLGA NPs), DTX-loaded HA-surfaced and non-crosslinked linear-PLGA nanoparticles (DTX-HA-lPLGA NPs), and free DTX (IC₅₀ = 0.18 versus 0.38, 1.21 and 0.83 µg DTX equiv./mL). Intriguingly, DTX-HA-sPLGA XNPs revealed a prolonged elimination half-life of 4.18 h and notable accretion of 9.49%ID/g in A549 tumor after 8 h injection. Accordingly, DTX-HA-sPLGA XNPs demonstrated significantly better suppression of subcutaneous A549 lung tumor than DTX-HA-PLGA NPs, DTX-HA-lPLGA NPs, and free DTX controls. HA-sPLGA XNPs with low toxicity and multi-functionality appear to be a unique targeted vehicle for chemotherapy of CD44-overexpressing tumors. STATEMENT OF SIGNIFICANCE: PLGA nanoparticles with superior safety and biodegradability are among the most advanced vehicles for therapeutic delivery. The efficacy of nanomedicines based on PLGA is, however, suboptimal, due to poor tumor cell selectivity and uptake, drug leakage, and slow drug release at the pathological site. It is highly desired to develop functional PLGA nanoparticles to improve their tumor-targeting ability and therapeutic efficacy. The sophisticated fabrication and potential toxicity concerns of reported novel PLGA nanoformulations, nevertheless, preclude their clinical translation. Here, we developed hyaluronic acid-surfaced and disulfide-crosslinked star-PLGA nanoparticles (HA-sPLGA XNPs) that enabled stable encapsulation and targeted delivery of docetaxel (DTX) to CD44+ A549 lung cancer cells in vitro and in vivo, affording markedly improved tumor accumulation and repression and lower side effects compared with free DTX control. Importantly, HA-sPLGA XNPs are based on fully biocompatible materials and comparably simple to fabricate. The evident tumor targetability and safety makes HA-sPLGA XNPs a unique and potentially translatable platform for chemotherapy of CD44+ cancers.

α3 integrin-binding peptide-functionalized polymersomes loaded with volasertib for dually-targeted molecular therapy for ovarian cancer

Ovarian cancer (OC) is a high-mortality malignancy in women with a five-year survival rate of 30-40%. There is an urgent need to develop high-efficacy and low toxic treatments for OC. Herein, we report an appealing strategy that combines α₃ integrin targeted polymersomes (A3-Ps) and targeted molecular drug, polo-like kinase 1 (PLK1) inhibitor volasertib (Vol) for dually targeted molecular therapy of OC in vivo. A3-Ps had good Vol loading of 7.7-8.0 wt.% and small size of 25-32 nm, depending on the density of α₃ integrin binding peptide A3. Interestingly, cellular uptake studies using FITC-labeled Vol revealed that A3-Ps with 20% peptide gave 2.3 and 3.3-fold better internalization in SKOV-3 OC cells compared with non-targeted Ps and free Vol, respectively. Accordingly, Vol loaded in A3-Ps showed the best inhibitory activity to SKOV-3 cells with an IC₅₀ of 49 nM, which was 3.5 times lower than free Vol. Importantly, the in vivo experiments demonstrated that A3-Ps-Vol proficiently repressed the growth of SKOV-3 tumors in mice while continuous tumor growth was observed for Ps-Vol and free Vol-treated mice. A3-Ps-Vol besides boosting anti-OC activity also reduced the systemic toxicity of Vol. This dually targeted molecular drug nanoformulation has appeared to be an especially potent and low toxic treatment modality for human ovarian cancers. STATEMENT OF SIGNIFICANCE: Volasertib provides a potential molecular therapy for PLK1-positive advanced OC patients. The initial clinical outcomes, nevertheless, showed a suboptimal efficacy, possibly resulting from its fast clearance, deficient tumor deposition and dose-limiting toxicities. Here, we show for the first time that dually targeted molecular therapy of OC using α₃ integrin-binding peptide-modified polymersomes as a vehicle gives markedly improved potency, better toleration, and depleted adverse effects in SKOV-3 tumor models, greatly outperforming free volasertib. This dually targeted strategy has emerged as an appealing treatment for malignant PLK1-positive ovarian tumors.

Leukocyte-Mediated Combined Targeted Chemo and Gene Therapy for Esophageal Cancer

Poor prognosis of esophageal cancer is associated with limited clinical treatment efficacy and lack of targeted therapies. With advances in nanomedicine, nanoparticle drug delivery systems play increasingly important roles in tumor treatment by enabling the simultaneous delivery of multiple therapeutic agents. We here propose a novel nanovector for targeted combination gene therapy and chemotherapy in esophageal cancer. A novel lipid nanovector (EYLN) was designed to carry the chemotherapy drug doxorubicin (Dox) and small interfering RNA against the lipid anabolic metabolism gene LPCAT1, which we previously showed to be significantly overexpressed in esophageal cancer tissues, and its interference inhibited the proliferation, invasion, and metastasis of esophageal cancer cells. This vector, EYLN-Dox/siLPCAT1, was further coated with leukocyte membranes to obtain mEYLNs-Dox/siLPCAT1. The particle size of the coated nanovector was approximately 136 nm, and the surface zeta potential was -21.18 mV. Compared with EYLNs-Dox/siLPCAT1, mEYLNs-Dox/siLPCAT1 were more easily internalized by esophageal cancer cells due to the LFA-1 highly expressed leukocyte membrane coating and showed significant inhibition of the proliferation, migration, and metastasis of esophageal cancer cells, along with their LPCAT1 expression, through more effective delivery of the drugs. Moreover, the nanovectors showed improved blood circulation time, tissue distribution, tumor targeting, and tumor suppression in a mouse model. Thus, combining chemo and gene therapy with this new nanodelivery system achieved greater therapeutic efficacy, providing a new strategy for the treatment of esophageal cancer.

SP94 peptide mediating highly specific and efficacious delivery of polymersomal doxorubicin hydrochloride to hepatocellular carcinoma in vivo

The effective treatment of hepatocellular carcinoma (HCC) requires development of novel drug formulations that selectively kill HCC cells while sparing healthy liver cells. Here, we designed and investigated HCC-specific peptide, SP94 (SFSIIHTPILPLGGC), decorated smart polymersomal doxorubicin hydrochloride (SP94-PS-DOX) for potent treatment of orthotopic human SMMC-7721 HCC xenografts. SP94-PS-DOX was fabricated by post ligand-modification, affording robust nano-formulations with a diameter of ∼ 76 nm and DOX content of 9.9 wt.%. The internalization of SP94-PS-DOX by SMMC-7721 cells showed a clear dependence on SP94 surface densities, in which 30 % SP94 resulted in ca. 3-fold better cellular uptake over non-targeted control (PS-DOX). In accordance, SP94-PS-DOX exhibited superior inhibition of SMMC-7721 cells to PS-DOX and clinical liposome injections (Lipo-DOX). Notably, a remarkable tumor deposition of 14.9 %ID/g and tumor-to-normal liver ratio of ca. 6.9 was observed for SP94-PS-DOX in subcutaneous SMMC-7721 HCC xenografts. More interestingly, SP94-PS-DOX under 10 mg DOX/kg induced far better therapeutic efficacy toward orthotopic SMMC-7721 HCC models than PS-DOX and Lipo-DOX controls giving substantial survival benefits and little adverse effects. The remarkable specificity and therapeutic outcomes lend SP94-PS-DOX promising for targeted HCC therapy.

100th Anniversary of Macromolecular Science Viewpoint: Biological Stimuli-Sensitive Polymer Prodrugs and Nanoparticles for Tumor-Specific Drug Delivery

The development of smart polymer vehicles to carry and release cytotoxic drugs to tumor tissues and cells while reducing the exposure of drugs in the blood and healthy organs is a highly challenging task with continuously growing interest from multiple fields, including polymer science, pharmaceutical science, nanotechnology, and clinical oncology. Inspired by the unique tumor microenvironment, such as mild acidity and overexpressed enzymes, functional polymer prodrugs and nanoparticles with reversible charge, detachable PEG shell, activatable ligand, and switchable size have been designed to enhance tumor deposition, tumor penetration, tumor cell uptake, and tumoral drug release. Utilizing biological signals inside tumor cells, such as acidic endo/lysosomal pH, elevated glutathione levels, and reactive oxygen species, responsive polymer prodrugs and nanoparticles with good extracellular stability but fast intracellular disintegration have been engineered for specific intracellular drug release. These biological stimuli-sensitive polymer prodrugs and nanoparticles have shown superior specificity and therapeutic efficacy to nonsensitive counterparts and, in certain cases, even clinically approved systems in varying tumor models. In this Viewpoint, design strategies and recent advances of biological stimuli-responsive polymer prodrugs and nanoparticles for tumor-specific drug delivery will be highlighted, and their challenges and future perspectives will be discussed.

GE11 peptide-installed chimaeric polymersomes tailor-made for high-efficiency EGFR-targeted protein therapy of orthotopic hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains a leading malignancy with a high mortality and little improvement in treatments. Protein drugs though known for their extraordinary potency and specificity have rarely been investigated for HCC therapy owing to lack of appropriate delivery systems. Here, we designed GE11 peptide-installed chimaeric polymersomes (GE11-CPs) for high-efficiency EGFR-targeted protein therapy of orthotopic SMMC-7721 HCC-bearing nude mice. GE11-CPs were assembled from poly(ethylene glycol)-b-poly(trimethylene carbonate-co-dithiolane trimethylene carbonate)-b-poly(aspartic acid) (PEG-P(TMC-DTC)-PAsp) and GE11-functionalized PEG-P(TMC-DTC), which allowed efficient loading and protection of proteins in the watery interior and fine-tuning of GE11 densities at the surface. CPs with short PAsp segments (degree of polymerization (DP) = 5, 10 and 15) exhibited a protein loading efficiency of 60%-72% and glutathione-responsive protein release. Saporin-loaded GE11-CPs had a size of 36 - 62 nm depending on GE11 densities and DP of PAsp. Notably, GE11-CPs with 10% GE11 revealed greatly enhanced uptake in SMMC-7721 cells, boosting the anticancer potency of saporin for over 3-folds compared with non-targeted control (half-maximal inhibitory concentration (IC₅₀) = 11.0 versus 36.3 nM). The biodistribution studies using Cy5-labeled cytochrome C as a model protein demonstrated about 3-fold higher accumulation of GE11-CPs formulation than CPs counterpart in both subcutaneous and orthotopic SMMC-7721 tumor models. Notably, saporin-loaded GE11-CPs revealed low toxicity, effective tumor inhibition and significant improvement of survival rate compared with PBS and non-targeted groups (median survival time: 99 versus 37 and 42 days). EGFR-targeted chimaeric polymersomes carrying proteins appear an interesting HCC treatment modality.

Advancements in nanotechnology for the diagnosis and treatment of multiple myeloma

Multiple myeloma (MM), known as a tumor of plasma cells, is not only refractory but also has a high relapse rate, and is the second-most common hematologic tumor after lymphoma. It is often accompanied by multiple osteolytic damage, hypercalcemia, anemia, and renal insufficiency. In terms of diagnosis, conventional detection methods have many limitations, such as it is invasive and time-consuming and has low accuracy. Measures to change these limitations are urgently needed. At the therapeutic level, although the survival of MM continues to prolong with the advent of new drugs, MM remains incurable and has a high recurrence rate. With the development of nanotechnology, nanomedicine has become a powerful way to improve the current diagnosis and treatment of MM. In this review, the research progress and breakthroughs of nanomedicine in MM will be presented. Meanwhile, both superiorities and challenges of nanomedicine were discussed. As a new idea for the diagnosis and treatments of MM, nanomedicine will play a very important role in the research field of MM.

Photoactivated H2 Nanogenerator for Enhanced Chemotherapy of Bladder Cancer

Hydrogen gas can mitigate oxidative stress in many diseases and is regarded to be safe and free of side effects. Inspired by a metalloenzyme in a variety of microorganisms, here, we propose a photoactivated H₂ nanogenerator that comprises a fluorinated chitosan (FCS), a chemotherapeutic drug (gemcitabine, GEM), and a catalyst of H₂ production ([FeFe]TPP) that can form self-assembled [FeFe]TPP/GEM/FCS nanoparticles (NPs). The [FeFe]TPP/GEM/FCS NPs exhibit excellent transmucosal and tumor cell penetration capacities after intravesical instillation into the bladder and can efficiently produce H₂ gas in situ upon 660 nm laser irradiation, which significantly enhances the efficacy of hydrogen chemotherapy of cancer in vitro and in vivo. Moreover, we discover that H₂ gas in hydrogen chemotherapy can inhibit mitochondrial function, hinder ATP synthesis, and cause a reduction of the P-gp efflux pump function, which finally attenuates P-gp protein drug transport capacity in cancer cells. This photoactivated H₂ evolution in situ to improve the therapeutic efficacy of chemotherapy of bladder cancer may present an effective hydrogen chemotherapy strategy for cancer treatment.

Emerging era of “somes”: polymersomes as versatile drug delivery carrier for cancer diagnostics and therapy

Over the past two decades, polymersomes have been widely investigated for the delivery of diagnostic and therapeutic agents in cancer therapy. Polymersomes are stable polymeric vesicles, which are prepared using amphiphilic block polymers of different molecular weights. The use of high molecular weight amphiphilic copolymers allows for possible manipulation of membrane characteristics, which in turn enhances the efficiency of drug delivery. Polymersomes are more stable in comparison with liposomes and show less toxicity in vivo. Furthermore, their ability to encapsulate both hydrophilic and hydrophobic drugs, significant biocompatibility, robustness, high colloidal stability, and simple methods for ligands conjugation make polymersomes a promising candidate for therapeutic drug delivery in cancer therapy. This review is focused on current development in the application of polymersomes for cancer therapy and diagnosis. Graphical abstract.