Reducing Interstitial Fluid Pressure and Inhibiting Pulmonary Metastasis of Breast Cancer by Gelatin Modified Cationic Lipid Nanoparticles

Construction of a Multifunctional Upconversion Nanoplatform Based on Autophagy Inhibition and Photodynamic Therapy Combined with Chemotherapy for Antitumor Therapy

Inhibition of autophagy increases the sensitivity of tumor cells to radiotherapy and chemotherapy and improves the therapeutic effect on tumors. Recently, photodynamic therapy (PDT) combined with chemotherapy has been proven to further improve the efficiency of cancer treatment. As such, combining autophagy inhibition with PDT and chemotherapy may represent a potentially effective new strategy for cancer treatment. However, currently widely studied autophagy inhibitors inevitably produce various toxic side effects due to their inherent pharmacological activity. To overcome this constraint, in this study, we designed an ideal multifunctional upconversion nanoplatform, UCNP-Ce6-EPI@mPPA + NIR (MUCEN). Control, UCNP-EPI@mPPA (MUE), UCNP-EPI@mPPA + NIR (MUEN), Ce6-EPI@mPPA (MCE), Ce6-EPI@mPPA + NIR (MCEN), and UCNP-Ce6-EPI@mPPA (MUCE) groups were set up separately as controls. Based on a combination of autophagy inhibition and PDT, the average particle size of MUCEN was 197 nm, which can simultaneously achieve the double encapsulation of chlorine e6 (Ce6) and epirubicin (EPI). In vitro tests revealed that MUCE was efficiently endocytosed by 4T1 cells under near-infrared light irradiation. Further, in vivo tests revealed that MUCE dramatically inhibited tumor growth. Immunohistochemistry results indicated that MUCE efficiently increased the expression of autophagy inhibitors p62 and LC3 in tumor tissues. The synergistic effect of autophagy inhibition and PDT with MUCE exhibited superior tumor suppression, providing an innovative approach to cancer treatment.

Achieving deep intratumoral penetration and multimodal combined therapy for tumor through algal photosynthesis

BACKGROUND

Elevated interstitial fluid pressure within tumors, resulting from impaired lymphatic drainage, constitutes a critical barrier to effective drug penetration and therapeutic outcomes.

RESULTS

In this study, based on the photosynthetic characteristics of algae, an active drug carrier (CP@ICG) derived from Chlorella pyrenoidosa (CP) was designed and constructed. Leveraging the hypoxia tropism and phototropism exhibited by CP, we achieved targeted transport of the carrier to tumor sites. Additionally, dual near-infrared (NIR) irradiation at the tumor site facilitated photosynthesis in CP, enabling the breakdown of excessive intratumoral interstitial fluid by generating oxygen from water decomposition. This process effectively reduced the interstitial pressure, thereby promoting enhanced perfusion of blood into the tumor, significantly improving deep-seated penetration of chemotherapeutic agents, and alleviating tumor hypoxia.

CONCLUSIONS

CP@ICG demonstrated a combined effect of photothermal/photodynamic/starvation therapy, exhibiting excellent in vitro/in vivo anti-tumor efficacy and favorable biocompatibility. This work provides a scientific foundation for the application of microbial-enhanced intratumoral drug delivery and tumor therapy.

Dual peptides-modified cationic liposomes for enhanced Lung cancer gene therapy by a gap junction regulating strategy

BACKGROUND

Gene therapy for lung cancer has emerged as a novel tumor-combating strategy for its superior tumor specificity, low systematical toxicity and huge clinical translation potential. Especially, the applications of microRNA shed led on effective tumor ablation by directly interfering with the crucial gene expression, making it one of the most promising gene therapy agents. However, for lung cancer therapy, the microRNA treatment confronted three bottlenecks, the poor tumor tissue penetration effect, the insufficient lung drug accumulation and unsatisfied gene transfection efficiency. To address these issues, an inhalable RGD-TAT dual peptides-modified cationic liposomes loaded with microRNA miR-34a and gap junction (GJ) regulation agent all-trans retinoic acid (ATRA) was proposed, which was further engineered into dry powder inhalers (DPIs).

RESULTS

Equipped with a rough particle surface and appropriate aerodynamic size, the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs were expected to deposit into the deep lung and reach lung tumor lesions guided by targeting peptide RGD. Assisted by cellular transmembrane peptides TAT, the RGD-TAT-CLPs/ARTA@miR-34a was proven to be effectively internalized by cancer cells, enhancing gene transfection efficiency. Then, the GJ between tumor cells was upregulated by ARTA, facilitating the intercellular transport of miR-34a and boosting the gene expression in the deep tumor.

CONCLUSION

Overall, the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs could enhance tumor tissue penetration, elevate lung drug accumulation and boost gene transfection efficiency, breaking the three bottlenecks to enhancing tumor elimination in vitro and in vivo. We believe that the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs could serve as a promising pulmonary gene delivery platform for multiple lung local disease treatments.

Challenges and Opportunities Associated With Drug Delivery for the Treatment of Solid Tumors

In this review, we discuss the effectiveness of drug delivery system based on metal nanoparticles, and also, describe the problems associated with their delivery to tumor cells. Throughout recent years, more reports have appeared in the literature that demonstrate promising results for the treatment of various types of cancer using metal-based nanoparticles. Due to their unique physical and chemical properties, metal nanoparticles are effectively being used for the delivery of drug to the tumor cells, for cancer diagnosis and treatment. They can also be synthesized allowing the control of size and shape. However, the effectiveness of the metal nanoparticles for cancer treatment largely depends on their stability, biocompatibility, and ability to selectively affect tumor cells after their systemic or local administration. Another major problem associated with metal nanoparticles is their ability to overcome tumor tissue barriers such as atypical blood vessel structure, dense and rigid extracellular matrix, and high pressure of tumor interstitial fluid. The review also describes the design of tumor drug delivery systems that are based on metal nanoparticles. The mechanism of action of metal nanoparticles on cancer cells is also discussed. Considering the therapeutic safety and toxicity of metal nanoparticles, the prospects for their use for future clinical applications are being currently reviewed.

Codelivery of Que and BCL-2 siRNA with Lipid-Copolymer Hybrid Nanocomplexes for Efficient Tumor Regression

The efficacy of chemotherapy is often reduced due to the chemotherapy resistance of tumor cells, which is usually caused by abnormal gene overexpression. Herein, multifunctional nanocomplexes (Que/siBCL2@BioMICs) were developed to deliver quercetin (Que) and BCL-2 siRNA (siBCL2) to synergistically inhibit tumor growth. The nanocomplexes were composed of an amphiphilic triblock copolymer of poly(ethylene glycol) methyl ether methacrylate-poly[2-(dimethylamino) ethyl acrylate]-polycaprolactone (PEGMA-PDMAEA-PCL) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)-biotin (DSPE-PEG-biotin). Que was encapsulated into the cores through hydrophobic interactions, while negatively charged siBCL2 was loaded through electrostatic interactions. The nanocomplexes could effectively facilitate cellular uptake via biotin-mediated active targeting and cytosolic release of cargos by the "proton sponge effect" of PDMAEA. Que/siBCL2@BioMICs achieved enhanced cytotoxicity and anti-metastasis activity due to a synergistic effect of Que and siBCL2 in vitro. More importantly, superior anti-tumor efficacy was observed in orthotopic 4T1 tumor-bearing mice with reduced primary tumor burden and lung metastatic nodules, while no obvious side effects to major organs were observed. In conclusion, the biotin-targeted nanocomplexes with chemotherapeutic and nucleotide agent entrapment provide a promising strategy for efficient triple-negative breast cancer (TNBC) therapy.

Perspectives for Improving the Tumor Targeting of Nanomedicine via the EPR Effect in Clinical Tumors

Over the past few decades, the enhanced permeability and retention (EPR) effect of nanomedicine has been a crucial phenomenon in targeted cancer therapy. Specifically, understanding the EPR effect has been a significant aspect of delivering anticancer agents efficiently to targeted tumors. Although the therapeutic effect has been demonstrated in experimental models using mouse xenografts, the clinical translation of the EPR effect of nanomedicine faces several challenges due to dense extracellular matrix (ECM), high interstitial fluid pressure (IFP) levels, and other factors that arise from tumor heterogeneity and complexity. Therefore, understanding the mechanism of the EPR effect of nanomedicine in clinics is essential to overcome the hurdles of the clinical translation of nanomedicine. This paper introduces the basic mechanism of the EPR effect of nanomedicine, the recently discussed challenges of the EPR effect of nanomedicine, and various strategies of recent nanomedicine to overcome the limitations expected from the patients' tumor microenvironments.

Multifunctional nanostructures: Intelligent design to overcome biological barriers

Over the past three decades, nanoscience has offered a unique solution for reducing the systemic toxicity of chemotherapy drugs and for increasing drug therapeutic efficiency. However, the poor accumulation and pharmacokinetics of nanoparticles are some of the key reasons for their slow translation into the clinic. The is intimately linked to the non-biological nature of nanoparticles and the aberrant features of solid cancer, which together significantly compromise nanoparticle delivery. New findings on the unique properties of tumors and their interactions with nanoparticles and the human body suggest that, contrary to what was long-believed, tumor features may be more mirage than miracle, as the enhanced permeability and retention based efficacy is estimated to be as low as 1%. In this review, we highlight the current barriers and available solutions to pave the way for approved nanoformulations. Furthermore, we aim to discuss the main solutions to solve inefficient drug delivery with the use of nanobioengineering of nanocarriers and the tumor environment. Finally, we will discuss the suggested strategies to overcome two or more biological barriers with one nanocarrier. The variety of design formats, applications and implications of each of these methods will also be evaluated.

Gelatin as a bioactive nanodelivery system for functional food applications

Gelatin has long been used as an encapsulant agent in the pharmaceutical and biomedical industries because of its low cost, wide availability, biocompatibility, and degradability. However, the exploitation of gelatin for nanodelivery application is not fully achieved in the functional food filed. In this review article, we highlight the latest work being performed for gelatin-based nanocarriers, including polyelectrolyte complexes, nanoemulsions, nanoliposomes, nanogels, and nanofibers. Specifically, we discuss the applications and challenges of these nanocarriers for stabilization and controlled release of bioactive compounds. To achieve better efficacy, gelatin is frequently used in combination with other biomaterials such as polysaccharides. The fabrication and synergistic effects of the newly developed gelatin composite nanocarriers are also present.

The Combination of Immune Checkpoint Blockade with Tumor Vessel Normalization as a Promising Therapeutic Strategy for Breast Cancer: An Overview of Preclinical and Clinical Studies

Immune checkpoint inhibitors (ICIs) have a modest clinical activity when administered as monotherapy against breast cancer (BC), the most common malignancy in women. Novel combinatorial strategies are currently being investigated to overcome resistance to ICIs and promote antitumor immune responses in a greater proportion of BC patients. Recent studies have shown that the BC abnormal vasculature is associated with immune suppression in patients, and hampers both drug delivery and immune effector cell trafficking to tumor nests. Thus, strategies directed at normalizing (i.e., at remodeling and stabilizing) the immature, abnormal tumor vessels are receiving much attention. In particular, the combination of ICIs with tumor vessel normalizing agents is thought to hold great promise for the treatment of BC patients. Indeed, a compelling body of evidence indicates that the addition of low doses of antiangiogenic drugs to ICIs substantially improves antitumor immunity. In this review, we outline the impact that the reciprocal interactions occurring between tumor angiogenesis and immune cells have on the immune evasion and clinical progression of BC. In addition, we overview preclinical and clinical studies that are presently evaluating the therapeutic effectiveness of combining ICIs with antiangiogenic drugs in BC patients.

Recent advances in flavonoid-based nanocarriers as an emerging drug delivery approach for cancer chemotherapy

Flavonoids are an interesting class of biomolecules, which exhibit cancer-inhibitory effects through both chemopreventive and chemotherapeutic activities. However, their therapeutic efficacy is affected by poor pharmacokinetics (PK) and biopharmaceutical attributes. One of the most promising approaches to resolve these issues is to formulate flavonoids in nanosystems. Different flavonoid nanoformulations have shown therapeutic superiority over free flavonoids. Functionalization of nanoparticles (NPs) further improves their therapeutic efficacy by facilitating site-specific delivery and reducing nonspecific toxicities. In this review, we highlight recent developments in the field of flavonoid-based NPs to gain translational insights into the potential applications of flavonoid-based nanocarriers in cancer management.

Targeting hormone-resistant breast cancer cells with docetaxel: a look inside the resistance

Aim: The study aims to analyze the effect of long-term incubation of ERα-positive MCF7 breast cancer cells with 4-hydroxytamoxifen (HT) on their sensitivity to tubulin polymerization inhibitor docetaxel. Methods: The analysis of cell viability was performed by the MTT method. The expression of signaling proteins was analyzed by immunoblotting and flow cytometry. ERα activity was evaluated by gene reporter assay. To establish hormone-resistant subline MCF7, breast cancer cells were treated with 4-hydroxytamoxifen for 12 months. Results: The developed MCF7/HT subline has lost sensitivity to 4-hydroxytamoxifen, and the resistance index was 2. Increased Akt activity (2.2-fold) and decreased ERα expression (1.5-fold) were revealed in MCF7/HT cells. The activity of the estrogen receptor α was reduced (1.5-fold) in MCF7/HT. Evaluation of class III β-tubulin expression (TUBB3), a marker associated with metastasis, revealed the following trends: higher expression of TUBB3 was detected in triple-negative breast cancer MDA-MB-231 cells compared to hormone-responsive MCF7 cells (P < 0.05). The lowest expression of TUBB3 was found in hormone-resistant MCF7/HT cells (MCF7/HT < MCF7 < MDA-MB-231, approximately 1:2:4). High TUBB3 expression strongly correlated with docetaxel resistance: IC₅₀ value of docetaxel for MDA-MB-231 cells was greater than that for MCF7 cells, whereas resistant MCF7/HT cells were the most sensitive to the drug. The accumulation of cleaved PARP (a 1.6-fold increase) and Bcl-2 downregulation (1.8-fold) were more pronounced in docetaxel-treated resistant cells (P < 0.05). The expression of cyclin D1 decreased (2.8-fold) only in resistant cells after 4 nM docetaxel treatment, while this marker was unchanged in parental MCF7 breast cancer cells. Conclusion: Further development of taxane-based chemotherapy for hormone-resistant cancer looks highly promising, especially for cancers with low TUBB3 expression.

Advances in nanomaterial-based targeted drug delivery systems

Nanomaterial-based drug delivery systems (NBDDS) are widely used to improve the safety and therapeutic efficacy of encapsulated drugs due to their unique physicochemical and biological properties. By combining therapeutic drugs with nanoparticles using rational targeting pathways, nano-targeted delivery systems were created to overcome the main drawbacks of conventional drug treatment, including insufficient stability and solubility, lack of transmembrane transport, short circulation time, and undesirable toxic effects. Herein, we reviewed the recent developments in different targeting design strategies and therapeutic approaches employing various nanomaterial-based systems. We also discussed the challenges and perspectives of smart systems in precisely targeting different intravascular and extravascular diseases.

A pHe sensitive nanodrug for collaborative penetration and inhibition of metastatic tumors

Current chemotherapies for metastatic tumors are seriously restricted by limited drug infiltration and deficient disturbance of metastasis-associated complex pathways involving tumor cell autocrine as well as paracrine loops in the microenvironment (TME). Of note, cancer-associated fibroblasts (CAFs) play a predominant role in shaping TME favoring drug resistance and metastasis. Herein, we constructed a tumor extracellular pH (pH_e) sensitive methotrexate-chitosan conjugate (MTX-GC-DEAP) and co-assembled it with quercetin (QUE) to achieve co-delivered nanodrugs (MTX-GC-DEAP/QUE). The pH_e sensitive protonation and disassembly enabled MTX-GC-DEAP/QUE for stroma-specific delivery of QUE and positive-charged MTX-GC-DEAP molecular conjugates, thereby achieving deep tumor penetration via the combination of QUE-mediated CAF inactivation and adsorption-mediated transcytosis. On the basis of significantly promoted drug availability, a strengthened "omnidirectional" inhibition of pre-metastatic initiation was generated both in vitro and in vivo from the CAF inactivation-mediated reversion of metastasis-promoting environments as well as the inhibition of epithelial-mesenchymal transition, local and blood vessel invasion via QUE-mediated direct regulation on tumor cells. Our tailor-designed versatile nanodrug provides a deep insight into potentiating multi-faceted penetration of multi-mechanism-based regulating agents for intensive metastasis inhibition.

Interstitial fluid pressure as an emerging biomarker in solid tumors

The physical microenvironment of cancer is characterized by elevated stiffness and tissue pressure, the main component of which is the interstitial fluid pressure (IFP). Elevated IFP is an established negative predictive and prognostic parameter, directly affecting malignant behavior and therapy response. As such, measurement of the IFP would allow to develop strategies aimed at engineering the physical microenvironment of cancer. Traditionally, IFP measurement required the use of invasive methods. Recent progress in dynamic and functional imaging methods such as dynamic contrast enhanced (DCE) magnetic resonance imaging and elastography, combined with numerical models and simulation, allows to comprehensively assess the biomechanical landscape of cancer, and may help to overcome physical barriers to drug delivery and immune cell infiltration. Here, we provide a comprehensive overview of the origin of elevated IFP, and its role in the malignant phenotype. Also, we review the methods used to measure IFP using invasive and imaging based methods, and highlight remaining obstacles and potential areas of progress in order to implement IFP measurement in clinical practice.

Inhalable Biomimetic Protein Corona-Mediated Nanoreactor for Self-Amplified Lung Adenocarcinoma Ferroptosis Therapy

Ferroptosis therapy by catalyzing the Fenton reaction has emerged as a promising tumor elimination strategy for lung adenocarcinoma (ADC). However, the unsatisfactory Fenton reaction efficiency, strong intracellular antioxidant system, and insufficient lung drug accumulation limits the ferroptosis therapeutic effect. To address these issues, an inhalable nanoreactor was proposed by spontaneously adsorbing biomimetic protein corona (PC) composed of matrix metalloproteinase 2 responsive gelatin and glutamate (Glu) on the surface of cationic nanostructured lipid carriers (NLC) core loaded with ferrocene (Fc) and fluvastatin. The prepared Fc-NLC(F)@PC could be nebulized into lung lesions with 2.6 times higher drug accumulation and boost lipid peroxide production by 3.2 times to enhance ferroptosis therapy. Mechanically, fluvastatin was proved to inhibit monocarboxylic acid transporter 4 mediated lactate efflux, inducing tumor acidosis to boost Fc-catalyzing reactive oxygen species production, while the extracellular elevating Glu concentration was found to inhibit xCT (system X_c^-) functions and further collapse the tumor antioxidant system by glutathione synthesis suppression. Mitochondrial dysfunction and cell membrane damage were involved in the nanoreactor-driven ferroptotic cell death process. The enhanced antitumor effects by combination of tumor acidosis and antioxidant system collapse were confirmed in an orthotopic lung ADC tumor model. Overall, the proposed nanoreactor highlights the pulmonary delivery approach for local lung ADC treatment and underscores the great potential of ferroptosis therapy.

Microbubbles Ultrasonic Cavitation Regulates Tumor Interstitial Fluid Pressure and Enhances Sonodynamic Therapy

Sonodynamic therapy (SDT) is a promising treatment method for solid tumors. However, the high interstitial fluid pressure (IFP) in tumor tissues limits the accumulation of sonosensitizers. In the present study, microbubbles ultrasonic cavitation was used to regulate the tumor’s IFP and evaluate SDT effects. Rabbit VX2 tumor tissues were treated with microbubbles ultrasonic cavitation. The IFP of different tumor parts before and after cavitation was measured by the WIN method. The accumulation of the sonosensitizers hematoporphyrin monomethyl ether (HMME) in tumor tissues was observed using an ultramicro spectrophotometer and laser confocal microscope. Then, tumor-bearing rabbits were treated with SDT once a week for eight weeks and the therapeutic effect was evaluated. After microbubbles ultrasonic cavitation treatment, the tumor’s IFP decreased and the HMME concentration increased. We concluded that microbubbles ultrasonic cavitation can increase HMME accumulation in rabbit VX2 tumors and increase SDT therapeutic effects.

Effect of carbon numbers and structures of monosaccharides on the glycosylation and emulsion stabilization ability of gelatin

Herein, the effect of saccharide glycosylation by nine monosaccharides on bovine bone gelatin for the stabilization of fish oil-loaded emulsions was explored. The gelatin modification was analyzed and then the emulsifying properties of monosaccharide-modified gelatins were analyzed at pH 9.0 and 3.0. The results demonstrated that glycosylated gelatin structure, droplet stability, creaming stability, and liquid-gel transition time were dependent on monosaccharide carbon numbers, monosaccharide structures, and solution pH. Glycosylation modification of gelatins did not obviously change the emulsion droplet stability at pH 9.0, whereas it increased the emulsion droplet stability at pH 3.0. Glycosylation modification of gelatins did not obviously change the emulsion creaming index values (5.1%-8.4% at pH 9.0 and 25.8%-33.1% at pH 3.0). Three-carbon and four-carbon monosaccharides glycosylation significantly increased emulsion liquid-gel transition times. This work provided useful information to understand the effects of carbon numbers and structures of monosaccharides on the protein modification.

Mechanisms of Penetration Enhancement and Transport Utilizing Skin Keratine Liposomes for the Topical Delivery of Licochalcone A

Keratin liposomes have emerged as a useful topical drug delivery system given theirenhanced ability to penetrate the skin, making them ideal as topical drug vehicles. However, the mechanisms of the drug penetration enhancement of keratin liposomes have not been clearly elucidated. Therefore, licochalcone A(LA)-loaded skin keratin liposomes (LALs) were prepared to investigate their mechanisms of penetration enhancement on the skin and inB16F10 cells. Skin deposition studies, differential scanning calorimetry (DSC), attenuated total reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), and skin distribution and intracellular distribution studies were carried out to demonstrate the drug enhancement mechanisms of LALs. We found that the optimal application of LALs enhanced drug permeation via alterations in the components, structure, and thermodynamic properties of the stratum corneum (SC), that is, by enhancing the lipid fluidization, altering the skin keratin, and changing the thermodynamic properties of the SC. Moreover, hair follicles were the main penetration pathways for the LA delivery, which occurred in a time-dependent manner. In the B16F10 cells, the skin keratin liposomes effectively delivered LA into the cytoplasm without cytotoxicity. Thus, LAL nanoparticles are promising topical drug delivery systems for pharmaceutical and cosmetic applications.

Multistage pH-responsive codelivery liposomal platform for synergistic cancer therapy

Background

Small interfering RNA (siRNA) is utilized as a potent agent for cancer therapy through regulating the expression of genes associated with tumors. While the widely application of siRNAs in cancer treatment is severely limited by their insufficient biological stability and its poor ability to penetrate cell membranes. Targeted delivery systems hold great promise to selectively deliver loaded drug to tumor site and reduce toxic side effect. However, the elevated tumor interstitial fluid pressure and efficient cytoplasmic release are still two significant obstacles to siRNA delivery. Co-delivery of chemotherapeutic drugs and siRNA represents a potential strategy which may achieve synergistic anticancer effect. Herein, we designed and synthesized a dual pH-responsive peptide (DPRP), which includes three units, a cell-penetrating domain (polyarginine), a polyanionic shielding domain (ehG)n, and an imine linkage between them. Based on the DPRP surface modification, we developed a pH-responsive liposomal system for co-delivering polo-like kinase-1 (PLK-1) specific siRNA and anticancer agent docetaxel (DTX), D-Lsi/DTX, to synergistically exhibit anti-tumor effect.

Results

In contrast to the results at the physiological pH (7.4), D-Lsi/DTX lead to the enhanced penetration into tumor spheroid, the facilitated cellular uptake, the promoted escape from endosomes/lysosomes, the improved distribution into cytoplasm, and the increased cellular apoptosis under mildly acidic condition (pH 6.5). Moreover, both in vitro and in vivo study indicated that D-Lsi/DTX had a therapeutic advantage over other control liposomes. We provided clear evidence that liposomal system co-delivering siPLK-1 and DTX could significantly downregulate expression of PLK-1 and inhibit tumor growth without detectable toxic side effect, compared with siPLK-1-loaded liposomes, DTX-loaded liposomes, and the combinatorial administration.

Conclusion

These results demonstrate great potential of the combined chemo/gene therapy based on the multistage pH-responsive codelivery liposomal platform for synergistic tumor treatment.

Graphical Abstract

Strategies to improve the EPR effect: A mechanistic perspective and clinical translation

Many efforts have been made to achieve targeted delivery of anticancer drugs to enhance their efficacy and to reduce their adverse effects. These efforts include the development of nanomedicines as they can selectively penetrate through tumor blood vessels through the enhanced permeability and retention (EPR) effect. The EPR effect was first proposed by Maeda and co-workers in 1986, and since then various types of nanoparticles have been developed to take advantage of the phenomenon with regards to drug delivery. However, the EPR effect has been found to be highly variable and thus unreliable due to the complex tumor microenvironment. Various physical and pharmacological strategies have been explored to overcome this challenge. Here, we review key advances and emerging concepts of such EPR-enhancing strategies. Furthermore, we analyze 723 clinical trials of nanoparticles with EPR enhancers and discuss their clinical translation.

Smart Nanotherapeutics and Lung Cancer

Lung cancer is a significant health problem worldwide. Unfortunately, current therapeutic strategies lack a sufficient level of specificity and can harm adjacent healthy cells. Consequently, to address the clinical need, novel approaches to improve treatment efficiency with minimal side effects are required. Nanotechnology can substantially contribute to the generation of differentiated products and improve patient outcomes. Evidence from previous research suggests that nanotechnology-based drug delivery systems could provide a promising platform for the targeted delivery of traditional chemotherapeutic drugs and novel small molecule therapeutic agents to treat lung cancer cells more effectively. This has also been found to improve the therapeutic index and reduce the required drug dose. Nanodrug delivery systems also provide precise control over drug release, resulting in reduced toxic side effects, controlled biodistribution, and accelerated effects or responses. This review highlights the most advanced and novel nanotechnology-based strategies, including targeted nanodrug delivery systems, stimuli-responsive nanoparticles, and bio-nanocarriers, which have recently been employed in preclinical and clinical investigations to overcome the current challenges in lung cancer treatments.

Intrinsic nucleus-targeted ultra-small metal-organic framework for the type I sonodynamic treatment of orthotopic pancreatic carcinoma

BACKGROUND

Sonodynamic therapy (SDT) strategies exhibit a high tissue penetration depth and can achieve therapeutic efficacy by facilitating the intertumoral release of reactive oxygen species (ROS) with a short lifespan and limited diffusion capabilities. The majority of SDT systems developed to date are of the highly O2-dependent type II variety, limiting their therapeutic utility in pancreatic cancer and other hypoxic solid tumor types.

RESULTS

Herein, a nucleus-targeted ultra-small Ti-tetrakis(4-carboxyphenyl)porphyrin (TCPP) metal-organic framework (MOF) platform was synthesized and shown to be an effective mediator of SDT. This MOF was capable of generating large quantities of ROS in an oxygen-independent manner in response to low-intensity ultrasound (US) irradiation (0.5 W cm-2), thereby facilitating both type I and type II SDT. This approach thus holds great promise for the treatment of highly hypoxic orthotopic pancreatic carcinoma solid tumors. This Ti-TCPP MOF was able to induce in vitro cellular apoptosis by directly destroying DNA and inducing S phase cell cycle arrest following US irradiation. The prolonged circulation, high intratumoral accumulation, and nucleus-targeting attributes of these MOF preparations significantly also served to significantly inhibit orthotopic pancreatic tumor growth and prolong the survival of tumor-bearing mice following Ti-TCPP + US treatment. Moreover, this Ti-TCPP MOF was almost completely cleared from mice within 7 days of treatment, and no apparent treatment-associated toxicity was observed.

CONCLUSION

The nucleus-targeted ultra-small Ti-TCPP MOF developed herein represents an effective approach to the enhanced SDT treatment of tumors in response to low-intensity US irradiation.

Protease-triggered bioresponsive drug delivery for the targeted theranostics of malignancy

Proteases have a fundamental role in maintaining physiological homeostasis, but their dysregulation results in severe activity imbalance and pathological conditions, including cancer onset, progression, invasion, and metastasis. This striking importance plus superior biological recognition and catalytic performance of proteases, combining with the excellent physicochemical characteristics of nanomaterials, results in enzyme-activated nano-drug delivery systems (nanoDDS) that perform theranostic functions in highly specific response to the tumor phenotype stimulus. In the tutorial review, the key advances of protease-responsive nanoDDS in the specific diagnosis and targeted treatment for malignancies are emphatically classified according to the effector biomolecule types, on the premise of summarizing the structure and function of each protease. Subsequently, the incomplete matching and recognition between enzyme and substrate, structural design complexity, volume production, and toxicological issues related to the nanocomposites are highlighted to clarify the direction of efforts in nanotheranostics. This will facilitate the promotion of nanotechnology in the management of malignant tumors.

TGF-β blockade-improved chemo-immunotherapy with pH/ROS cascade-responsive micelle via tumor microenvironment remodeling

Immunosuppressive tumor microenvironment and low delivery efficiency severely impede the tumor chemotherapy effect. To address this issue, we develop a pH/ROS cascade-responsive prodrug micelle to deliver siTGF-β with size-shrinkage and charge-reversal property, leading to synergistical tumor microenvironment remodeling. The nanosystem highly improved endocytosis efficiency and tumor penetration depth through charge reversal and size reduction upon exposure to weakly acidic tumor microenvironment. Moreover, the nanocarrier would rapidly escape from endo/lysosome, disassemble and release siTGF-β and hydroxycamptothecin in response to high intracellular ROS. Furthermore, the nanosystem significantly boosted antitumor immune response and reduced immune tolerance with remodeling tumor microenvironment, which significantly prolonged the survival time of tumor-bearing mice (75% survival rate upon 35 days). It is realized by the combined effects of chemotherapy-enhanced immunogenicity and recruitment of effector T cells, TGF-β-blockade immunotherapy-activated inhibition immunosuppressive tumor microenvironment and epithelial-to-mesenchymal transition (EMT), and regulation physical tumor microenvironment via reducing the dense tumor extracellular matrix and the high tumor interstitial pressure obstacles. To this end, the nanosystem not only overcame biobarriers and reinforced antitumor immune response, but also effectively inhibited tumor growth, metastasis and recurrence in vivo.

Pyroelectric Catalysis-Based "Nano-Lymphatic" Reduces Tumor Interstitial Pressure for Enhanced Penetration and Hydrodynamic Therapy

Because of the deficiency of lymphatic reflux in the tumor, the retention of tumor interstitial fluid causes aggravation of the tumor interstitial pressure (TIP), which leads to unsatisfactory tumor penetration of nanomedicine. It is the main inducement of tumor recurrence and metastasis. Herein, we design a pyroelectric catalysis-based "Nano-lymphatic" to decrease the TIP for enhanced tumor penetration and treatments. It realizes photothermal therapy and decomposition of tumor interstitial fluid under NIR-II laser irradiation after reaching the tumor, which reduces the TIP for enhanced tumor penetration. Simultaneously, reactive oxygen species generated during the pyroelectric catalysis can further damage deep tumor stem cells. The results indicate that the "Nano-lymphatic" relieves 52% of TIP, leading to enhanced tumor penetration, which effectively inhibits the tumor proliferation (93.75%) and recurrence. Our finding presents a rational strategy to reduce TIP by pyroelectric catalysis for enhanced tumor penetration and improved treatments, which is of great significance for drug delivery.

The gate to metastasis: key players in cancer cell intravasation

Metastasis is a leading cause of cancer‐related death and consists of a sequence of events including tumor expansion, intravasation of cancer cells into the circulation, survival in the bloodstream, extravasation at distant sites, and subsequent organ colonization. Particularly, intravasation is a process whereby cancer cells transverse the endothelium and leave the primary tumor site, pioneering the metastatic cascade. The identification of those mechanisms that trigger the entry of cancer cells into the bloodstream may reveal fundamentally novel ways to block metastasis at its start. Multiple factors have been implicated in cancer progression, yet, signals that unequivocally provoke the detachment of cancer cells from the primary tumor are still under investigation. Here, we discuss the role of intrinsic properties of cancer cells, tumor microenvironment, and mechanical cues in the intravasation process, outlining studies that suggest the involvement of various factors and highlighting current understanding and open questions in the field.

Dithiocarbazate-Copper Complexes for Bioimaging and Treatment of Pancreatic Cancer

Anticancer agents that present nonapoptotic cell death pathways are required for treating apoptosis-resistant pancreatic cancer. Here, we synthesized three fluorescent dithiocarbazate-copper complexes, {[Cu^II(L)(Cl)] 1, [Cu^II₂(L)₂(NO₃)₂] 2, and [Cu^II₂Cu^I(L)₂(Br)₃] 3}, to assess their antipancreatic cancer activities. Complexes 1-3 showed significantly greater cytotoxicity toward several pancreatic cancer cell lines with better IC₅₀ than those of the HL ligand and cisplatin. Confocal fluorescence imaging showed that complex 3 was primarily localized in the mitochondria. Primarily, compound 3 also can be applied to in vivo imaging. Further studies revealed that complex 3 kills pancreatic cancer cells by triggering multiple mechanisms, including ferroptosis. Complex 3 is the first copper complex to evoke cellular events consistent with ferroptosis in cancer cells. Finally, it significantly retarded the ASPC-1 cells' growth in a mouse xenograft model.

On-demand responsive nanoplatform mediated targeting of CAFs and down-regulating mtROS-PYK2 signaling for antitumor metastasis

The desmoplastic tumor microenvironment (DTME), including overexpressed stromal cells and extracellular matrix, formed the first barrier for the accumulation and penetration of nanoparticles in tumors, which compromised the therapeutic efficacy and prognosis. In some metastatic cells, overactivity of the tricarboxylic cycle could overload the electron transport chain resulting in increased mtROS production, which triggered the mitochondria-driven tumor migration and metastasis. Hence, we developed HPBC@TRP/NPs for down-regulating the mtROS-PYK2 pathway and remodeling the DTME to inhibit tumor growth and metastasis for the first time. TPP-RSV prodrugs were synthesized and targeted at mitochondria, resulting in the scavenging of mtROS, lower PYK2 expression, and activation of the mitochondria-driven apoptotic pathway. Pirfenidone fully remodeled the DTME through inhibiting the expression of CAFs, hyaluronan and collagen I, thereby reducing IFP, eliminating the immunosuppressive microenvironment by decreasing the expression of TGF-β, and increasing the infiltration of cytotoxic T lymphocytes. The combination therapy of different mechanisms via targeting the mtROS-PYK2 pathway and CAFs might provide deeper insights into the inhibition of malignant breast cancer growth and metastasis.

Piezo 1 activation facilitates cholangiocarcinoma metastasis via Hippo/YAP signaling axis

Tumor metastasis is one of the major factors for the high mortality in cholangiocarcinoma (CCA), but its underlying mechanisms are not fully understood. Here, we report that Piezo-type mechanosensitive ion channel component 1 (Piezo 1) is detected to be significantly upregulated in CCA tissues, which is linked to a poor prognosis in patients, suggesting that Piezo 1 may act in a pro-metastatic role in CCA development. Piezo 1 is activated through 20% simulated physiological stretch, and deleting Piezo 1 impedes epithelial-to-mesenchymal transition (EMT) of CCA cells, as well as impairing their metastatic capacity in vitro and in vivo. Mechanistically, the activation of Piezo 1 results in large amounts of Yes-associated protein 1 (YAP) translocated into the nucleus from the cytoplasm, and thus the motility of CCA cells is significantly increased. These findings indicate that mechanical stimulation induces Piezo 1 activation, which might be involved in CCA metastasis via the Hippo/YAP signaling axis. Therefore, Piezo 1 and its downstream effectors may be a novel therapeutic target for CCA treatment.

Regulation of tumor microenvironment for pancreatic cancer therapy

Pancreatic cancer (PC) is one kind of the most lethal malignancies worldwide, owing to its insidious symptoms, early metastases, and negative responses to current therapies. With an increasing understanding of pathology, the tumor microenvironment (TME) plays a significant role in ineffective treatment and poor prognosis of PC. Thus, a growing number of studies have focused on whether components of the TME could be effective targets for PC therapy. Biomaterials have been widely applied in cancer therapy, and numerous organic or inorganic biomaterials for TME regulation have been developed to inhibit the growth and metastasis of PC, as well as reverse therapeutic resistance. In this review, we discuss various biomaterials utilized to treat PC based on different components of the TME, including, but not limited to, extracellular matrix (ECM), abnormal tumor vascularization, and tumor-associated immune cells, as well as other unconventional therapeutic strategies. Besides, the perspectives on the underlying future of theranostic nanomedicines for PC therapy are also presented.

Dual-Responsive and Deep-Penetrating Nanomicelles for Tumor Therapy via Extracellular Matrix Degradation and Oxidative Stress

Tumor microenvironment (TME), with complex composition, plays a vital role in the occurrence, development, and metastasis of tumors. TME becomes an important obstacle to the accessibility of nanotherapy, thus indicating the need to improve the functional design to overcome this challenge. In this study, we generate an intelligent nano-drug-delivery system (DOX@PssP-Hh NPs) with dual environmental response, which involves heparanase (HPSE) in TME and glutathione (GSH) in tumor cells. The nanosystem consists of a nanoskeleton formed by self-assembly of mPEG-ss-PEI and α-CD (PssP), chemotherapy drug doxorubicin (DOX) for enhancing antitumor efficacy, together with hyaluronidase (HAase), which is designed to degrade extracellular matrix to increase drug penetration, and an outer shell of heparin. Through the process of "responsive disintegration-remodeling tumor microenvironment-enhancing drug penetration-inducing oxidative stress", the semi-rotaxaneself-assembled nanomicelles were constructed to achieve the progressive function. DOX@PssP-Hh NPs with the size of 81.85 ± 1.85 nm exhibited satisfactory cytotoxicity (IC₅₀ = 0.80 ± 0.33 μg/mL). With the disulfide bond-mediated GSH depletion and DOX-mediated reactive oxygen species (ROS) production, treatment with DOX@PssP-Hh NPs prominently reduced glutathione peroxidase 4 (GPX4) level and would lead to enhanced oxidative stresses. Hyaluronic acid (HA), collagen I, and α-smooth muscle actin (α-SMA) were significantly reduced for TME remodulation. Moreover, the antitumor effect in vivo implied that DOX@PssP-Hh NPs could inhibit tumor growth effectively and reduce tumor interstitial fluid pressure (IFP) evidently. In conclusion, DOX@PssP-Hh NPs improved the penetration of drugs and exhibited enhanced antitumor efficacy.

Bioengineered siRNA-Based Nanoplatforms Targeting Molecular Signaling Pathways for the Treatment of Triple Negative Breast Cancer: Preclinical and Clinical Advancements

Triple negative breast cancer (TNBC) is one of the most aggressive types of breast cancer. Owing to the absenteeism of hormonal receptors expressed at the cancerous breast cells, hormonal therapies and other medications targeting human epidermal growth factor receptor 2 (HER2) are ineffective in TNBC patients, making traditional chemotherapeutic agents the only current appropriate regimen. Patients' predisposition to relapse and metastasis, chemotherapeutics' cytotoxicity and resistance and poor prognosis of TNBC necessitates researchers to investigate different novel-targeted therapeutics. The role of small interfering RNA (siRNA) in silencing the genes/proteins that are aberrantly overexpressed in carcinoma cells showed great potential as part of TNBC therapeutic regimen. However, targeting specificity, siRNA stability, and delivery efficiency cause challenges in the progression of this application clinically. Nanotechnology was highlighted as a promising approach for encapsulating and transporting siRNA with high efficiency-low toxicity profile. Advances in preclinical and clinical studies utilizing engineered siRNA-loaded nanotherapeutics for treatment of TNBC were discussed. Specific and selective targeting of diverse signaling molecules/pathways at the level of tumor proliferation and cell cycle, tumor invasion and metastasis, angiogenesis and tumor microenvironment, and chemotherapeutics' resistance demonstrated greater activity via integration of siRNA-complexed nanoparticles.

Biologically active Camellia oleifera protein nanoparticles for improving the tumor microenvironment and drug delivery

It is important for antitumor drugs to accumulate at the tumor site and penetrate deeply to play a role in treatment. However, it is difficult for the drugs to reach the destination on account of the complex tumor microenvironment such as elevated tumor interstitial fluid pressure (IFP) and solid stress. Here, we report a type of nanocarrier composed entirely of Camellia oleifera protein (COP), which could lower tumor IFP and solid stress. Its physicochemical properties, cellular uptake, in vitro cytotoxicity and tumor perfusion, biodistribution, and in vivo antitumor efficiency were evaluated. It was found that COP NPs had good cellular uptake ability and cytocompatibility. When loading doxorubicin, COP NPs showed an in vitro concentration-dependent cytotoxicity. Importantly, the tumor IFP and solid stress were greatly reduced after injecting COP NPs into tumor-bearing mice, leading to more drug accumulating in the tumor and a longer survival time for tumor-bearing mice. Therefore, our study provided a new strategy to improve the tumor microenvironment and to achieve better antitumor efficiency.

Recent Advances in Nanostrategies Capable of Overcoming Biological Barriers for Tumor Management

Engineered nanomaterials have been extensively employed as therapeutics for tumor management. Meanwhile, the complex tumor niche along with multiple barriers at the cellular level collectively hinders the action of nanomedicines. Here, the advanced strategies that hold promise for overcoming the numerous biological barriers facing nanomedicines are summarized. Starting from tumor entry, methods that promote tissue penetration of nanomedicine and address the hypoxia issue are also highlighted. Then, emphasis is given to the significance of overcoming both physical barriers, such as membrane-associated efflux pumps, and biological features, such as resistance to apoptosis. The pros and cons for an individual approach are presented. In addition, the associated technical problems are discussed, along with the importance of balancing the therapeutic merits and the additional cost of sophisticated nanomedicine designs.

Critical considerations for targeting colorectal liver metastases with nanotechnology

Colorectal cancer remains a significant cause of morbidity and mortality worldwide. Half of all patients develop liver metastases, presenting unique challenges for their treatment. The shortcomings of conventional chemotherapy has encouraged the use of nanomedicines; the application of nanotechnology in the diagnosis and treatment of disease. In spite of technological improvements in nanotechnology, the complexity of biological systems hinders the prospect of nanomedicines being applied in cancer therapy at the present time. This review highlights current biological barriers and discusses aspects of tumor biology together with the physicochemical features of the nanocarrier, that need to be considered in order to develop effective nanotherapeutics for colorectal cancer patients with liver metastases. It becomes clear that incorporating an interdisciplinary approach when developing nanomedicines should assure appropriate disease-driven design and that this will form a critical step in improving their clinical translation. This article is characterized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Development of gelatin/bacterial cellulose composite sponges as potential natural wound dressings

A novel BG composite sponge comprising of bacterial cellulose (BC) and gelatin has been synthesized using glutaraldehyde as the cross-linker by a facile method. The morphology, chemical composition and structures of the novel sponges were characterized by SEM, EDS and FTIR spectroscopy. The fabricated BG sponges have regular honeycomb-like structure with uniform pore distribution and large surface area. They have very high porosity of 94%-95% and great swelling property ranging from 3000 to 3150%. Moreover, the released rate of the model drug ampicillin (AP) from the composite sponges depends on the initial addition of AP that the diffusional constant (n) determined using Korsmeyer-Peppas model lies between 0.45 and 0.89, indicating the AP release from BG composite sponges follows non-Fickian diffusion. More interestingly, antibacterial activity of BG sponges was investigated by diffusion disk method against E.coli, C. albicans and S. aureus. The results demonstrated that the obtained BG sponges exhibit excellent antibacterial activity, thus making them have great potentials in various antibacterial applications, especially in the wound dressings.

Dual-Responsive Size-Shrinking Nanocluster with Hierarchical Disassembly Capability for Improved Tumor Penetration and Therapeutic Efficacy

It is generally known that, for nanoparticles in cancer therapy, sufficient tumor penetration needs a minor particle size, while long in vivo circulation time needs a larger particle size. It is hard to balance them because they are standing on either side of a seesaw. To address these two different requirements, a dual-responsive size-shrinking nanocluster can self-adaptively respond to a complicated tumor microenvironment and transform its particulate property to overcome sequential in vivo barriers and reach a preferable antitumor activity. The nanocluster (RPSPT@SNCs) could preferentially accumulate into tumor tissue and dissociate under extracellular matrix metalloproteinase-2 (MMP-2) to release small-sized micelle formulations (RPSPTs). RPSPT possesses favorable tumor penetration and tumor targeting capability to deliver the antitumor agent paclitaxel (PTX) into deep regions of solid tumor. The intracellular redox microenvironment can also accelerate drug accumulation. The prepared RPSPT@SNCs possesses enhanced cell cytotoxicity and tumor penetration capability on MCF-7 cells and a favorable antitumor activity on the xenograft tumor mouse model.

Doxorubicin conjugated with nanodiamonds and in free form commit glioblastoma cells to heterodromous fates

Aim: To mechanistically compare the effects of doxorubicin (DOX) and DOX conjugated with nanodiamonds (Nano–DOX) on human glioblastoma cells (GC). Materials & methods: GC viablity, proliferation and activation of apoptosis and autophagy was assayed in response to DOX and Nano–DOX. Expression and release of HMGB1 were measured and its role in apoptosis and autophagy probed in response to DOX and Nano–DOX.  Results: DOX induced apoptosis in GC while Nano–DOX induced autophagy. Inhibition of autophagy in Nano–DOX-treated GC promoted apoptosis. DOX suppressed the emission of HMGB1 while Nano–DOX stimulated HMGB1 emission which was attenuated when autophagy was repressed. Blocking of HMGB1 emission mitigated autophagy and enhanced apoptosis in Nano–DOX-treated GC. Exogenously administered HMGB1 promoted autophagy and protected against apoptosis in both Nano–DOX-treated GC and DOX-treated GC. Conclusions: Nano–DOX is a potent autophagy activator as opposed to DOX as an apoptosis inducer. Nano–DOX initiates a mutual reinforcement loop between autophagy and HMGB1 in GC and thereby protects GC against apoptosis.

Hyaluronic acid-modified cationic nanoparticles overcome enzyme CYP1B1-mediated breast cancer multidrug resistance

Aim: Enzyme CYP1B1 (CYP1B1) is usually overexpressed in multidrug resistance (MDR) breast cancer cells, which could metabolically inactivate docetaxel (DTX). Materials & methods: The cationic core–shell nanoparticles (hyaluronic acid/polyethyleneimine nanoparticles [HA/PEI NPs]) modified with hyaluronic acid (HA) were developed and coloaded with DTX and α-napthtoflavone (ANF, a CYP1B1 inhibitor) to overcome MDR in breast cancer induced by CYP1B1. Physicochemical characterization, MDR reversing effect in vitro and pharmacokinetics in vivo of HA/PEI NPs were evaluated. Results: The HA/PEI NPs exhibited spherical morphology with size of (193.6 ± 3.1) nm. The HA/PEI NPs could reverse MDR effectively by downregulating the expression of CYP1B1. The HA/PEI NPs improved the bioavailability of DTX. Conclusion: The HA/PEI NPs might be a promising strategy to overcome CYP1B1-mediated breast cancer MDR.

Saporin-loaded CD44 and EGFR dual-targeted nanogels for potent inhibition of metastatic breast cancer in vivo

Metastasis poses a long-standing treatment challenge for many cancers including breast cancer. Once spreading out, cell-selective delivery of drug appears especially critical. Here, we report on epidermal growth factor receptor and CD44 dual-targeted hyaluronic acid nanogels (EGFR/CD44-NGs) that afford enhanced targetability and protein therapy for metastatic 4T1 breast cancer in vivo. Flow cytometry in CD44 and EGFR-positive 4T1 metastatic breast cancer cells showed over 6-fold higher cellular uptake of EGFR/CD44-NGs than mono-targeting CD44-NGs. MTT and scratch assays displayed that saporin-loaded EGFR/CD44-NGs (Sap-EGFR/CD44-NGs) was highly potent in inhibiting growth as well as migration of 4T1 cells in vitro, with an IC₅₀ of 5.36 nM, which was 1.7-fold lower than that for Sap-CD44-NGs. In 4T1-luc metastatic breast cancer model in mice, Sap-EGFR/CD44-NGs exhibited significant inhibition of tumor metastasis to lung at a small dose of 3.33 nmol Sap equiv./kg. Increasing the dosage to 13.3 nmol Sap equiv./kg resulted in further reduced lung metastasis without causing notable adverse effects. These dual-targeted nanogels with improved cancer cell selectivity provide a novel platform for combating breast cancer metastasis.

Employment of enhanced permeability and retention effect (EPR): Nanoparticle-based precision tools for targeting of therapeutic and diagnostic agent in cancer

In tumorous tissues, the absence of vasculature supportive tissues intimates the formation of leaky vessels and pores (100 nm to 2 μm in diameter) and the poor lymphatic system offers great opportunity to treat cancer and the phenomenon is known as Enhanced permeability and retention (EPR) effect. The trends in treating cancer by making use of EPR effect is increasing day by day and generate multitudes of possibility to design novel anticancer therapeutics. This review aimed to present various factors affecting the EPR effect along with important things to know about EPR effect such as tumor perfusion, lymphatic function, interstitial penetration, vascular permeability, nanoparticle retention etc. This manuscript expounds the current advances and cross-talks the developments made in the of EPR effect-based therapeutics in cancer therapy along with a transactional view of its current clinical and industrial aspects.

Cancer nanomedicine: focus on recent developments and self-assembled peptide nanocarriers

The applications of nanoparticulate drug delivery have received abundant interest in the field of cancer diagnosis and treatment.

Enhanced nanoparticle delivery exploiting tumour-responsive formulations

Nanoparticles can be used as drug carriers, contrast agents and radiosensitisers for the treatment of cancer. Nanoparticles can either passively accumulate within tumour sites, or be conjugated with targeting ligands to actively enable tumour deposition. With respect to passive accumulation, particles < 150 nm accumulate with higher efficiency within the tumour microenvironment, a consequence of the enhanced permeability and retention effect. Despite these favourable properties, clinical translation of nano-therapeutics is inhibited due to poor in vivo stability, biodistribution and target cell internalisation. Nano-therapeutics can be modified to exploit features of the tumour microenvironment such as elevated hypoxia, increased pH and a compromised extracellular matrix. This is in contrast to cytotoxic chemotherapies which generally do not exploit the characteristic pathological features of the tumour microenvironment, and as such are prone to debilitating systemic toxicities. This review examines strategies for tumour microenvironment targeting to improve nanoparticle delivery, with particular focus on the delivery of nucleic acids and gold nanoparticles. Evidence for key research areas and future technologies are presented and critically evaluated. Among the most promising technologies are the development of next-generation cell penetrating peptides and the incorporation of micro-environment responsive stealth molecules.