Carrier-Free Nano-PROTACs to Amplify Photodynamic Therapy Induced DNA Damage through BRD4 Degradation.

Therapy-induced DNA damage is the most common strategy to inhibit tumor cell proliferation, but the therapeutic efficacy is limited by DNA repair machinery. Carrier-free nanoproteolysis targeting chimeras (PROTACs), designed as SDNpros, have been developed to enhance photodynamic therapy (PDT) by blocking the DNA damage repair pathway through BRD4 degradation. Specifically, SDNpros are constructed through noncovalent interactions between the photosensitizer of chlorine e6 (Ce6) and PROTACs of BRD4 degrader (dBET57) via self-assembly. SDNpro has favorable dispersibility and a uniform nanosize distribution without drug excipients. Upon light irradiation, SDNpro produces abundant reactive oxygen species (ROS) to induce DNA oxidative damage. Meanwhile, the DNA repair pathway would be interrupted by the concurrent degradation of BRD4, which could intensify the oxidative DNA damage and elevate PDT efficiency. Beneficially, SDNpro suppresses tumor growth and avoids systemic side effects, providing a promising strategy to promote the clinical translation of PROTACs for tumor treatment.

Cascade Immune Activation of Self-Delivery Biomedicine for Photodynamic Immunotherapy Against Metastatic Tumor.

Photodynamic therapy (PDT) can generate reactive oxygen species (ROS) to cause cell apoptosis and induce immunogenic cell death (ICD) to activate immune response, becoming a promising antitumor modality. However, the overexpressions of indoleamine 2,3-dioxygenase (IDO) and programmed cell death ligand 1 (PD-L1) on tumor cells would reduce cytotoxic T cells infiltration and inhibit the immune activation. In this paper, a simple but effective nanosystem is developed to solve these issues for enhanced photodynamic immunotherapy. Specifically, it has been constructed a self-delivery biomedicine (CeNB) based on photosensitizer chlorine e6 (Ce6), IDO inhibitor (NLG919), and PD1/PDL1 blocker (BMS-1) without the need for extra excipients. Of note, CeNB possesses fairly high drug content (nearly 100%), favorable stability, and uniform morphology. More importantly, CeNB-mediated IDO inhibition and PD1/PDL1 blockade greatly improve the immunosuppressive tumor microenvironments to promote immune activation. The PDT of CeNB not only inhibits tumor proliferation but also induces ICD response to activate immunological cascade. Ultimately, self-delivery CeNB tremendously suppresses the tumor growth and metastasis while leads to a minimized side effect. Such simple and effective antitumor strategy overcomes the therapeutic resistance against PDT-initiated immunotherapy, suggesting a potential for metastatic tumor treatment in clinic.

Carrier Free O2 -Economizer for Photodynamic Therapy Against Hypoxic Tumor by Inhibiting Cell Respiration.

Abnormal tumor metabolism causes the hypoxic microenvironment, which greatly limits the efficacy of photodynamic therapy (PDT). In this work, a strategy of metabolic reprogramming is proposed to economize O2 for enhanced PDT against hypoxic tumors. The carrier-free O2 -economizer (designated as LonCe) is prepared based on the metabolic antitumor drug of Lonidamine (Lon) and the photosensitizer of chlorin e6 (Ce6). By virtue of intermolecular interactions, Lon and Ce6 self-assemble into nanosized LonCe with favorable stability and high drug contents. Compared with Ce6, LonCe exhibits an improved cellular uptake and photodynamic property for tumor treatment. Moreover, LonCe is capable of inhibiting cell metabolism and mitochondrial respiration to remit the tumor hypoxia, which would promote reactive oxygen species (ROS) production and elevate the PDT efficacy on tumor suppression. In vivo experiments indicate that intravenously injected LonCe prefers to accumulate at the tumor site for highly efficient PDT regardless of the hypoxic environment. Besides, the self-delivery LonCe is fabricated without any carriers, which avoids the excipients induced system toxicity and immunogenicity in vivo. This carrier-free nanomedicine with cell respiratory inhibition mechanism would expedite the development and clinical translation of photodynamic nanoplatforms in tumor treatment.

Carrier Free Photodynamic Synergists for Oxidative Damage Amplified Tumor Therapy.

Tumor cells adapt to excessive oxidative stress by actuating reactive oxygen species (ROS)-defensing system, leading to a resistance to oxidation therapy. In this work, self-delivery photodynamic synergists (designated as PhotoSyn) are developed for oxidative damage amplified tumor therapy. Specifically, PhotoSyn are fabricated by the self-assembly of chlorine e6 (Ce6) and TH588 through π-π stacking and hydrophobic interactions. Without additional carriers, nanoscale PhotoSyn possess an extremely high drug loading rate (up to 100%) and they are found to be fairly stable in aqueous phase with a uniform size distribution. Intravenously injected PhotoSyn prefer to accumulate at tumor sites for effective cellular uptake. More importantly, TH588-mediated MTH1 inhibition could destroy the ROS-defensing system of tumor cells by preventing the elimination of 8-oxo-2'-deoxyguanosine triphosphate (8-oxo-dG), thereby exacerbating the oxidative DNA damage induced by the photodynamic therapy (PDT) of Ce6 under light irradiation. As a consequence, PhotoSyn exhibit enhanced photo toxicity and a significant antitumor effect. This amplified oxidative damage strategy improves the PDT efficiency with a reduced side effect by increasing the lethality of ROS without generating superabundant ROS, which would provide a new insight for developing self-delivery nanoplatforms in photodynamic tumor therapy in clinic.

Self-Delivery Nanomedicine for O2-Economized Photodynamic Tumor Therapy.

Tumor hypoxia is the Achilles heel of oxygen-dependent photodynamic therapy (PDT), and tremendous challenges are confronted to reverse the tumor hypoxia. In this work, an oxidative phosphorylation inhibitor of atovaquone (ATO) and a photosensitizer of chlorine e6 (Ce6)-based self-delivery nanomedicine (designated as ACSN) were prepared via π-π stacking and hydrophobic interaction for O2-economized PDT against hypoxic tumors. Specifically, carrier-free ACSN exhibited an extremely high drug loading rate and avoided the excipient-induced systemic toxicity. Moreover, ACSN not only dramatically improved the solubility and stability of ATO and Ce6 but also enhanced the cellular internalization and intratumoral permeability. Abundant investigations confirmed that ACSN effectively suppressed the oxygen consumption to reverse the tumor hypoxia by inhibiting mitochondrial respiration. Benefiting from the synergistic mechanism, an enhanced PDT effect of ACSN was observed on the inhibition of tumor growth. This self-delivery system for oxygen-economized PDT might be a potential appealing clinical strategy for tumor eradication.

[Chemical constituents from the twigs and leaves of Harrisonia perforate].

This study was performed to investigate the chemical constituents in the twigs and leaves of Harrisonia perforate. Six compounds were isolated from the 95% EtOH extract of the twigs and leaves of Harrisonia perforate by silica gel, ODS, Sephadex LH-20 column chromatographies and preparative HPLC. On the basis of chemical properties and spectra data, these compounds were identified as harriperfin E (1), kihadanin A (2), kihadanin B (3), 6α-acetoxyobacunol acetate (4), gardaubryone C (5), and ß-sitosterol methyl ether (6), respectively. Compound 1 is a new chromone, and compounds 2-6 are isolated from this plant for the first time.

Chemotherapy-Enabled Colorectal Cancer Immunotherapy of Self-Delivery Nano-PROTACs by Inhibiting Tumor Glycolysis and Avoiding Adaptive Immune Resistance.

The chemo-regulation abilities of chemotherapeutic medications are appealing to address the low immunogenicity, immunosuppressive lactate microenvironment, and adaptive immune resistance of colorectal cancer. In this work, the proteolysis targeting chimera (PROTAC) of BRD4 (dBET57) is found to downregulate colorectal cancer glycolysis through the transcription inhibition of c-Myc, which also inhibits the expression of programmed death ligand 1 (PD-L1) to reverse immune evasion and avoid adaptive immune resistance. Based on this, self-delivery nano-PROTACs (designated as DdLD NPs) are further fabricated by the self-assembly of doxorubicin (DOX) and dBET57 with the assistance of DSPE-PEG2000. DdLD NPs can improve the stability, intracellular delivery, and tumor targeting accumulation of DOX and dBET57. Meanwhile, the chemotherapeutic effect of DdLD NPs can efficiently destroy colorectal cancer cells to trigger a robust immunogenic cell death (ICD). More importantly, the chemo-regulation effects of DdLD NPs can inhibit colorectal cancer glycolysis to reduce the lactate production, and downregulate the PD-L1 expression through BRD4 degradation. Taking advantages of the chemotherapy and chemo-regulation ability, DdLD NPs systemically activated the antitumor immunity to suppress the primary and metastatic colorectal cancer progression without inducing any systemic side effects. Such self-delivery nano-PROTACs may provide a new insight for chemotherapy-enabled tumor immunotherapy.

Chlorin e6 and BLZ945 Based Self-Assembly for Photodynamic Immunotherapy Through Immunogenic Tumor Induction and Tumor-Associated Macrophage Depletion.

Immunotherapeutic effect is restricted by the nonimmunogenic tumor phenotype and immunosuppression behaviors of tumor-associated macrophages (TAMs). In this work, a drug self-assembly (designated as CeBLZ) is fabricated based on chlorin e6 (Ce6) and BLZ945 to activate photodynamic immunotherapy through tumor immunogenic induction and tumor-associated macrophage depletion. It is found that Ce6 tends to assemble with BLZ945 without any drug excipients, which can enhance the cellular uptake, tumor penetration, and blood circulation behaviors. The robust photodynamic therapy effect of CeBLZ efficiently suppresses the primary tumor growth and also triggers immunogenic cell death to reverse the nonimmunogenic tumor phenotype. Moreover, CeBLZ can deplete TAMs in tumor tissues to reverse the immunosuppression microenvironment, activating abscopal effect for distant tumor inhibition. In vitro and in vivo results confirm the superior antitumor effect of CeBLZ with negligible side effect, which might promote the development of sophisticated drug combinations for systematic tumor management.

[Chemical studies on roots of Ficus hirta].

Seventeen compounds were isolated from the 95% ethanolic extract of the root of Ficus hirta. Their structures were identified on the basis of physicochemical properties and spectral data analysis. The structures were elucidated as cyclomorusin (1), 3-O-[(6-O-E-sinapoyl)-beta-D-glucopyranosyl]-(1 --> 2)-beta-D-glucopyranoside (2), 3,5,4'-trihydroxy-6,7,3'-trimethoxyflavone (3), quercetin (4), tricin (5), acacetin (6), luteolin (7), apigenin (8), (E) -suberenol (9), meranzin hydrate (10), methyl eugenol (11), 3-methoxy-4-hydroxybenzoic acid (12), p-hydroxybenzoic acid (13), methyl chlorogenate (14), emodin (15), alpha-amyrin acetate (16), and beta-sitosterol emodin (17), respectively. Compounds 1-6, 9-15 were isolated from this plant for the first time.

Coordination-Driven Self-Assembly of Biomedicine to Enhance Photodynamic Therapy by Inhibiting Proteasome and Bcl-2.

Tumor cells resist oxidative damage and apoptosis by activating defense mechanisms. Herein, a self-delivery biomedicine (designated as BSC) is developed by the self-assembly of Bortezomib (BTZ), Sabutoclax (Sab) and Chlorin e6 (Ce6). Interestingly, BTZ can be coordinated with Sab to promote the assembly of uniform ternary biomedicine through non-covalent intermolecular interactions. Moreover, BTZ as a proteasome inhibitor can prevent tumor cells from scavenging damaged proteins to reduce their oxidative resistance. Sab can downregulate B-cell lymphoma 2 (Bcl-2) to decrease the antiapoptotic protein. Both the proteasome and Bcl-2 inhibitions contribute to increasing cell apoptosis and amplifying photodynamic therapy (PDT) efficacy of Ce6. Encouragingly, carrier-free BSC receives all biological activities of these assembly elements, including photodynamic performance as well as inhibitory capabilities of proteasome and Bcl-2. Besides, BSC has a preferable cellular uptake ability and tumor retention property, which increase the drug delivery efficiency and bioavailability. In vitro and in vivo research demonstrate the superior PDT efficiency of BSC by proteasome and Bcl-2 inhibitions. Of special note, the coordination-driven self-assembly of BSC is pH-responsive, which can be disassembled for controlled drug release upon tumor acidic microenvironment. This study will expand the applicability of self-delivery nanomedicine with sophisticated mechanisms for tumor treatment.

Paraptosis Inducer to Effectively Trigger Immunogenic Cell Death for Metastatic Tumor Immunotherapy with IDO Inhibition.

Paraptosis is characterized by the extensive vacuolization of endoplasmic reticulum (ER) and mitochondria, which will cause the release of damage-associated molecular patterns to promote immunogenic cell death (ICD). However, the tumor can develop an immunosuppressive microenvironment to affect the ICD activation for the purpose of immune escape. Herein, a paraptosis inducer (CMN) is constructed to amplify the ICD effect for efficient immunotherapy by inhibiting the activity of indoleamine 2,3-dioxygenase (IDO). Initially, CMN is prepared by the assembly of copper ions (Cu2+), morusin (MR), and IDO inhibitor (NLG919) through noncovalent interactions. Without the need for extra drug carriers, CMN possesses very high drug contents and exhibits a favorable GSH responsiveness for disassembly. Subsequently, the released MR can trigger paraptosis to cause extensive vacuolization of ER and mitochondria, contributing to activating ICD for immunotherapy. Moreover, NLG919 would inhibit IDO to remodel the tumor microenvironment and promote the activation of cytotoxic T cells, leading to an intensive antitumor immunity. Abundant in vivo studies indicate that CMN is superior in suppressing the proliferations of not only primary tumor but also metastatic and rechallenged tumors. Such a GSH-responsive paraptosis inducer might provide a promising strategy to trigger ICD and enhance tumor immunotherapy.

Self-Delivery Ternary Bioregulators for Photodynamic Amplified Immunotherapy by Tumor Microenvironment Reprogramming.

Abnormal metabolism of cancer cells results in complex tumor microenvironments (TME), which play a dominant role in tumor metastasis. Herein, self-delivery ternary bioregulators (designated as TerBio) are constructed for photodynamic amplified immunotherapy against colorectal cancer by TME reprogramming. Specifically, carrier-free TerBio are prepared by the self-assembly of chlorine e6, SB505124 (SB), and lonidamine (Lon), which exhibit improved tumor accumulation, tumor penetration, and cellular uptake behaviors. Interestingly, TerBio-mediated photodynamic therapy (PDT) could not only inhibit the primary tumor growth but also induce immunogenic cell death of tumors to activate the cascade immune response. Furthermore, TerBio are capable of TME reprograming by SB-triggered transforming growth factor (TGF)-ß blockage and Lon-induced lactic acid efflux inhibition. As a consequence, TerBio significantly suppresses distant and metastatic tumor growth by PDT-amplified immunotherapy. This study might advance the development of self-delivery nanomedicine against malignant tumor growth and metastasis.

A carrier free photodynamic oxidizer for enhanced tumor therapy by redox homeostasis disruption.

Abnormal tumor microenvironments play important roles in cancer progression. In general, tumor cells are capable of upregulating glutathione (GSH) levels to maintain aberrant redox homeostasis and cause resistance to oxidative damage. Herein, we develop a photodynamic oxidizer to disrupt the redox homeostasis of tumor cells for enhanced photodynamic tumor therapy. Based on pyropheophorbide-a (Pyro) and naphthazarin (Nap), a carrier free photodynamic oxidizer (named PyroNap) is prepared by the self-assembly technique through hydrophobic interactions. It is confirmed that nanosized PyroNap has high drug contents as well as favorable dispersity and stability. Besides, the photodynamic property of Pyro has obviously improved after self-assembly into the nanomedicine of PyroNap, which facilitates the production of reactive oxygen species (ROS) for robust photodynamic therapy (PDT). More importantly, the Nap induced GSH decrease could disrupt the redox homeostasis of tumor cells to further improve the PDT efficacy on tumor suppression. Consequently, after intravenous administration, PyroNap was able to significantly inhibit tumor growth and cause minimal side effects. This study might shed light on developing translational nanomedicine for tumor precision therapy.

Photodynamic Therapy Initiated Ferrotherapy of Self-Delivery Nanomedicine to Amplify Lipid Peroxidation via GPX4 Inactivation.

Lipid peroxide (LPO) is the hallmark of ferroptosis, which is a promising antitumor modality for its unique advantages. However, a cellular defense system would weaken the antitumor efficacy of ferrotherapy. Herein, a GPX4 inhibitor of ML162 and a photosensitizer of chlorine e6 (Ce6) are used to prepare the self-delivery nanomedicine (C-ML162) through hydrophobic and electrostatic interactions to enhance ferroptosis by photodynamic therapy (PDT). Specifically, carrier-free C-ML162 improves the solubility, stability, and cellular uptake of antitumor agents. Upon light irradiation, the internalized C-ML162 generates large amounts of reactive oxygen species (ROS) to oxidize cellular unsaturated lipid into LPO. More importantly, C-ML162 can directly inactivate GPX4 to enhance the accumulation of toxic LPO, inducing ferroptotic cell death. Additionally, C-ML162 is capable of accumulating at a tumor site for effective treatment. This self-delivery system to amplify lipid peroxidation via GPX4 inactivation for PDT initiated ferrotherapy might provide an appealing strategy against malignancies.

Self-Delivery Nanomedicine for Glutamine-Starvation Enhanced Photodynamic Tumor Therapy.

Glutamine metabolism of tumor cells plays a crucial role in maintaining cell homeostasis and reducing oxidative damage. Herein, a valid strategy of inhibiting glutamine metabolism is proposed to amplify the oxidative damage of photodynamic therapy (PDT) to tumor cells. Specifically, the authors develop a drug co-delivery system (designated as CeV) based on chlorine e6 (Ce6) and V9302 via the self-assembly technology. In spite of the strong hydrophobicity of therapeutic agents, the assembled CeV holds a favorable dispersibility in water and an improved cellular uptake capability. Under light irradiation, the internalized CeV is capable of generating abundant reactive oxygen species (ROS) for PDT. More importantly, CeV can reduce the uptake of glutamine through V9302-mediated alanine-serine-cysteine transporter of type-2 (ASCT2) inhibition, leading to a reduced glutathione (GSH) production and an amplified oxidative stress. As a result, CeV has a robust PDT efficacy on tumor inhibition by the blockade of glutamine transport. Notably, CeV exhibits a superiority on tumor suppression over the single treatment as well as the combined administration of Ce6 and V9302, which indicates the advantage of CeV for synergistic treatment. It may serve as a novel nanoplatform for developing a drug co-delivery system to improve PDT efficiency by inhibiting cell metabolism.

Self-delivery nanomedicine to overcome drug resistance for synergistic chemotherapy.

Multidrug resistance (MDR) is one of the prime reasons for the failure of cancer chemotherapy, which continues to be a great challenge to be solved. In this work, α-tocopherol succinate (α-TOS) and doxorubicin (DOX)-based self-delivery nanomedicine (designated as α-TD) is prepared to combat drug resistance for cancer synergistic chemotherapy. Carrier-free α-TD possesses a fairly high drug loading rate and improves the cellular uptake via the endocytosis pathway. More importantly, the apoptotic inducer α-TOS could elevate the reactive oxygen species (ROS) generation, disrupt mitochondrial function and reduce adenosine 5'-triphosphate (ATP) production, which facilitate the intracellular drug retention while decreasing its efflux. As a result, α-TD achieves a considerable synergistic chemotherapeutic effect against drug resistant cancer cells. Moreover, it also exhibits a preferable inhibitory effect on tumor growth with a low system toxicity in vivo. This synergistic drug self-delivery strategy would open a new window for developing carrier-free nanomedicine for overcoming drug resistance in cancer therapy.

Mitochondria Targeted O2 Economizer to Alleviate Tumor Hypoxia for Enhanced Photodynamic Therapy.

Photodynamic therapy (PDT) often suffers from the exacerbated tumor hypoxia and the heterogeneous distribution of photosensitizers, leading to an inefficient ROS productivity and availability. In this work, a mitochondria targeted O2 economizer (designated as Mito-OxE) is developed to improve PDT efficiency by alleviating tumor hypoxia and enhancing the subcellular localization of photosensitizers. Specifically, the photosensitizer of protoporphyrin IX (PpIX) is modified with the hydrophilic polyethylene glycol and the lipophilic cation of triphenylphosphine (TPP) to fabricate the biocompatible mitochondria targeted photosensitizers (designated as Mito-PSs). And Mito-OxE is prepared by using Mito-PSs to load the mitochondrial oxidative phosphorylation inhibitors of atovaquone (ATO). Benefiting from the targeting capability of TPP, Mito-OxE can selectively accumulate in mitochondria after cellular uptake. Subsequently, the mitochondrial respiration would be suppressed to with the participation of ATO, resulting in a local hypoxia mitigation for enhanced PDT. Compared with Mito-PSs, Mito-OxE maximizes the therapeutic effect against hypoxic tumors under light irradiation. This design of mitochondria targeted O2 economizer would advance the development of targeted drug delivery system for effective PDT regardless of hypoxic microenvironment.

Self-Delivery Photo-Immune Stimulators for Photodynamic Sensitized Tumor Immunotherapy.

Self-delivery of photosensitizer and immune modulator to tumor site is highly recommendable to improve the photodynamic immunotherapy yet remains challenging. Herein, self-delivery photoimmune stimulators (designated as iPSs) are developed for photodynamic sensitized tumor immunotherapy. Carrier-free iPSs are constructed by optimizing the noncovalent interactions between the pure drugs of chlorine e6 (Ce6) and NLG919, which avoid the excipients-raised toxicity and immunogenicity. Intravenously administrated iPSs prefer to passively accumulate on tumor tissues for a robust photodynamic therapy (PDT) with the induction of immunogenetic cell death (ICD) cascade to activate cytotoxic T lymphocytes (CTLs) and initiate antitumor immune response. Meanwhile, the concomitant delivery of NLG919 inhibits the activation of indoleamine 2,3-dioxygenase 1 (IDO-1) to reverse the immunosuppressive tumor microenvironment. Ultimately, the photodynamic sensitized immunotherapy with iPSs efficiently inhibit the primary and distant tumor growth with a low system toxicity, which would shed light on the development of self-delivery nanomedicine for clinical transformation in tumor precision therapy.

Ratiometric theranostic nanoprobe for pH imaging-guided photodynamic therapy.

An abnormal pH microenvironment results from the development of tumors, and also affects the therapeutic efficiency of anti-tumor drugs. In this work, a Förster resonance energy transfer (FRET)-based theranostic fluorescent nanoprobe was constructed for simultaneous ratiometric pH sensing and tumor-targeted photodynamic therapy. Based on the FRET process between rhodamine B and protoporphyrin IX (PpIX), the fabricated nanoprobe exhibited excellent pH responsiveness in both solutions and live cells with the ratiometric fluorescence changes. Moreover, this ratiometric pH fluorescent nanoprobe also possessed the capability for pH-responsive singlet oxygen (1O2) generation under light irradiation, guiding robust photodynamic therapy in a pH-dependent manner. Benefiting from the enhanced permeability and retention (EPR) effect, the nanoprobe could significantly inhibit tumor growth and metastasis via targeted photodynamic therapy in vivo. This work presents a novel paradigm for precise tumor theranostics by ratiometric pH fluorescence imaging-guided photodynamic therapy.

Chimeric peptide engineered exosomes for dual-stage light guided plasma membrane and nucleus targeted photodynamic therapy.

Targeted delivery of the drug to its therapeutically active site with low immunogenicity and system toxicity is critical for optimal tumor therapy. In this paper, exosomes as naturally-derived nano-sized membrane vesicles are engineered by chimeric peptide for plasma membrane and nucleus targeted photosensitizer delivery and synergistic photodynamic therapy (PDT). Importantly, a dual-stage light strategy is adopted for precise PDT by selectively and sequentially destroying the plasma membrane and nucleus of tumor cells. Briefly, plasma membrane-targeted PDT of chimeric peptide engineered exosomes (ChiP-Exo) could directly disrupt the membrane integrity and cause cell death to some extent. More interestingly, the photochemical internalization (PCI) and lysosomal escape triggered by the first-stage light significantly improve the cytosolic delivery of ChiP-Exo, which could enhance its nuclear delivery due to the presence of nuclear localization signals (NLS) peptide. Upon the second-stage light irradiation, the intranuclear ChiP-Exo would activate reactive oxygen species (ROS) in situ to disrupt nuclei for robust and synergistic PDT. Based on exosomes, this dual-stage light guided subcellular dual-targeted PDT strategy exhibits a greatly enhanced therapeutic effect on the inhibition of tumor growth with minimized system toxicity, which also provides a new insight for the development of individualized biomedicine for precise tumor therapy.