Disrupting tumour blood vessels

STING-activating layered double hydroxide nano-adjuvants for enhanced cancer immunotherapy

Cancer vaccines represent a promising therapeutic strategy in oncology, yet their effectiveness is often hampered by suboptimal antigen targeting, insufficient induction of cellular immunity, and the immunosuppressive tumor microenvironment. Advanced delivery systems and potent adjuvants are needed to address these challenges, though a restricted range of adjuvants for human vaccines that are approved, and even fewer are capable of stimulating robust cellular immune response. In this work, we engineered a unique self-adjuvanted platform (MLDHs) by integrating STING agonists manganese into a layered double hydroxide nano-scaffold, encapsulating the model antigen ovalbumin (OVA). The MLDHs platform encompasses Mn-doped MgAl-LDH (MLMA) and Mn-doped MgFe-LDH (MLMF). Upon subcutaneous injection, OVA/MLDHs specifically accumulated within lymph nodes (LNs), where they were internalized by resident antigen-presenting cells. The endosomal degradation of MLDHs facilitated the cytoplasmic release of antigen and Mn2+, promoting cross-presentation and triggering the STING pathway, which in turn induced a potent cellular immune response against tumors. Notably, OVA/MLMF induced stronger M1 macrophage polarization and a more potent T-cell response within tumor-infiltrating lymphocytes compared to OVA/MLMA, leading to significant tumor regression in B16F10-OVA bearing mice with minimal adverse effects. Additionally, combining MLMF with the vascular disrupting agent Vadimezan disrupted the tumor's central region, typically resistant to immune cell infiltration, further extending survival in tumor-bearing mice. This innovative strategy may show great potential for improving cancer immunotherapy and offers hope for more effective treatments in the future.

Selective vascular disrupting therapy by lipid nanoparticle-mediated Fas ligand silencing and stimulation of STING

Although recent therapeutic developments have greatly improved the outcomes of patients with cancer, it remains on ongoing problem, particularly in relation to acquired drug resistance. Vascular disrupting agents (VDAs) directly damage tumor blood vessels, thus promoting drug efficacy and reducing the development of drug resistance; however, their low molecular weight and resulting lack of selectivity for tumor endothelial cells (TECs) lead to side effects that can hinder their practical use. Here, we report a novel tumor vascular disrupting therapy using nucleic acid-loaded lipid nanoparticles (LNPs). We prepared two LNPs: a small interfering RNA (siRNA) against Fas ligand (FasL)-loaded cyclic RGD modified LNP (cRGD-LNP) to knock down FasL in TECs and a stimulator of interferon genes (STING) agonist-loaded LNP to induce systemic type I interferon (IFN) production. The combination therapy disrupted the tumor vasculature and induced broad tumor cell apoptosis within 48 h, leading to rapid and strong therapeutic effects in various tumor models. T cells were not involved in these antitumor effects. Furthermore, the combination therapy demonstrated a significantly superior therapeutic efficacy compared with conventional anti-angiogenic agents and VDAs. RNA sequencing analysis suggested that reduced collagen levels may have been responsible for TEC apoptosis. These findings demonstrated a potential therapeutic method for targeting the tumor vasculature, which may contribute to the development of a new class of anti-cancer drugs.

Design, synthesis, and biological evaluation of hypoxic-activation prodrug TH-302 derivatives

This study aims to design and develop novel and efficient anti-hypoxic cell tumor drugs. Using the TH-302 as lead compound, structural modifications are conducted to synthesize a series of novel derivatives to investigate the structural activity relationship (SAR) against ovarian cancer cell line (SKOV3) and glioblastoma cell line (U87MG) in vitro. The structural modifications mainly include four aspects: changes in substituents on N; changes in isomers; changes in nitro group position; changes in substituting halogens in phosphoramide mustard. The results of CCK-8 assay indicate that the steric hindrance and electronic effects of substituents on N have significant impacts on the activity, while changes in nitro group positions have minimal effects on the activity, and Bromo-phosphoramide mustard exhibits better activity than Chloro-phosphoramide mustard. Compounds 15c and 16d exhibit significantly superior antitumor activity compared to TH-302, with IC50 values of 42 μM and 32 μM for SKOV3 cells, and IC50 values of 47 μM and 41 μM for U87MG cells, respectively.

Evaluating Immune Activation Feasibility in Pancreatic Ductal Adenocarcinoma via Oxygen Bubble-Induced Anti-Vascular Therapy

Background/Objectives: Anti-vascular therapy presents a potential strategy for activating anti-tumor immunity. Disrupted vascular debris provides effective antigens that activate dendritic cells, leading to subsequent immune responses. However, the resulting tumor hypoxia following vascular disruption may contribute to immune suppression, thereby hindering effective immune activation. Ultrasound-stimulated microbubble cavitation can locally disrupt tumor vessels through mechanical effects to achieve physical anti-vascular therapy. Therefore, this study designed oxygen-loaded nanobubbles (ONBs) to combine anti-vascular effects with local oxygen release under ultrasound stimulation. The feasibility of enhancing anti-tumor immune activation by alleviating tumor hypoxia was evaluated. Methods: A murine pancreatic subcutaneous solid tumor model was used to evaluate the efficacy of anti-vascular therapy-associated immunotherapy. Results: After ONB treatment, tumor perfusion was reduced to 52 ± 5%, which resulted in a subsequent 57 ± 11% necrosis and a 29 ± 4% reduction in hypoxia, demonstrating the anti-vascular effect and reoxygenation, respectively. However, subsequent immune responses exhibited no significant activation in intratumoral cytokine expression or splenic immune cell composition. Primary tumors exhibited a 15.7 ± 5.0% increase in necrosis following ONB treatment, but distant tumor growth was not significantly inhibited. Conclusions: These results highlighted a crucial issue regarding the complex correlations between vessel disruption, antigen production, oxygen delivery, hypoxia, and immunity when combining anti-vascular therapy with immunotherapy.

Monoclonal Antibodies in Clinical Trials for Breast Cancer Treatment

One of the most potent therapeutic and diagnostic agents in contemporary medicine is the monoclonal antibody (mAb). mAbs can perform a variety of tasks in breast cancer (BC), including identifying and delivering therapeutic medications to targets, preventing cell development, and suppressing immune system inhibitors including directly attacking cancer cells. mAbs are one of the most effective therapeutic options, particularly for HER2, but they have not been well studied for their use in treating other forms of BC, particularly triple negative breast tumors. Bispecific and trispecific mAbs have created new opportunities for more targeted specific efficacy, which has a positive impact on the viability of antigen specificity. They are more versatile and effective than other forms of treatment, emerging as most popular option for treating BC. However, mAbs have a limit in treatment due to certain adverse effects, including fever, shaking, exhaustion, headache, nausea, and vomiting, as well as rashes, bleeding, and difficulty breathing. To examine the current and prospective future capacities of mAbs with regard to the detection and treatment of BC, the present review highlights advantages and disadvantages of mAb approach.

Overcoming Biological Barriers in Cancer Therapy: Cell Membrane-Based Nanocarrier Strategies for Precision Delivery

Given the unique capabilities of natural cell membranes, such as prolonged blood circulation and homotypic targeting, extensive research has been devoted to developing cell membrane-inspired nanocarriers for cancer therapy, while most focused on overcoming one or a few biological barriers. In fact, the journey of nanosystems from systemic circulation to tumor cells involves intricate processes, encompassing blood circulation, tissue accumulation, cancer cell targeting, endocytosis, endosomal escape, intracellular trafficking to target sites, and therapeutic action, all of which pose limitations to their clinical translation. This underscores the necessity of meticulously considering these biological barriers in the design of cell membrane-mimetic nanocarriers. In this review, we delineate the functions and applications of diverse types of cell membranes in nanocarrier systems. We elaborate on the biological hurdles encountered at each stage of the biomimetic nanoparticle's odyssey to the target, and comprehensively discuss the obstacles imposed by the tumor microenvironment for precise delivery. Subsequently, we systematically review contemporary cell membrane-based strategies aimed at overcoming these multi-level biological barriers, encompassing hybrid cell membrane (HCM) camouflage, tumor microenvironment remodeling, endosomal/lysosomal escape, multidrug resistance (MDR) reversal, optimization of nanoparticle physicochemical properties, and so on. Finally, we outline potential strategies to accelerate the development of cell membrane-inspired precision nanocarriers and discuss the challenges that must be addressed to enhance their clinical applicability. This review serves as a guide for refining the study of cell membrane-mimetic nanosystems in surmounting in vivo delivery barriers, thereby significantly contributing to advancing the development and application of cell membrane-based nanoparticles in cancer delivery.

Design, Synthesis and Biological Evaluation of 2-Phenyl Indole Analogues of OXi8006 as Colchicine Site Inhibitors of Tubulin Polymerization and Vascular Disrupting Agents

Inhibitors of tubulin polymerization represent a promising therapeutic approach for the treatment of solid tumors. Molecules that bind to the colchicine site are of interest as they can function with a dual mechanism of action as both potent antiproliferative agents and tumor-selective vascular disrupting agents (VDAs). One such example is a 2-aryl-3-aroyl-indole molecule (OXi8006) from our laboratory that demonstrates potent inhibition of tubulin polymerization and strong antiproliferative activity (cytotoxicity) against a variety of human cancer cell lines. A water-soluble prodrug OXi8007, synthesized from OXi8006, demonstrates in vivo disruption of tumor-associated microvessels in several tumor types (mouse models). The molecular framework of OXi8006 inspired a series of fourteen new 2-aryl-3-aroyl-indole analogues that incorporated various functional group modifications on both the indole core and the aroyl ring. Electron withdrawing and donating groups at the mono-substituted 3' position and the di-substituted 3',5' positions were all accommodated while maintaining inhibition of tubulin polymerization (IC50 < 5 μM), with several analogues demonstrating activity comparable to OXi8006 and the benchmark natural product combretastatin A-4 (CA4). Preliminary structure-activity relationship (SAR) studies were further enhanced by molecular docking to predict possible colchicine site interactions. Two analogues (KGP366 and KGP369) previously synthesized in our laboratory were re-synthesized using a somewhat modified route to increase synthetic efficiency and were subsequently converted to their corresponding water-soluble phosphate prodrug salts to evaluate their efficacy as VDAs. Administration of the prodrug salt (KGP415) of KGP369 caused significant reduction in bioluminescence signal from an orthotopic kidney tumor (RENCA-luc) in BALB/c mice, indicative of VDA activity. Collectively, these new functionalized indole-based analogues have extended SAR knowledge related to the colchicine binding site, and the most biologically active analogues hold promise for continued development as pre-clinical candidates for cancer therapy.

Reduced irradiation exposure areas enhanced anti-tumor effect by inducing DNA damage and preserving lymphocytes

BACKGROUND

Partial stereotactic body radiation therapy (SBRT) targeting hypoxic regions of large tumors (SBRT-PATHY) has been shown to enhance the efficacy of tumor radiotherapy by harnessing the radiation-induced immune response. This approach suggests that reducing the irradiation target volume not only achieves effective anti-tumor effects but also minimizes damage to surrounding normal tissues. In this study, we evaluated the antitumor efficacy of reduced-tumour-area radiotherapy (RTRT) , and explored the relationship between tumor control and immune preservation and the molecular mechanisms underlying of them.

METHODS

In mouse breast cancer models, we compared the anti-tumor effects of RTRT and conventional radiotherapy (CNRT) by assessing tumor growth, metastasis, and survival rates. Additionally, we evaluated the peritumoral tissue damage and the immune microenvironment. The maturation of dendritic cells (DCs) and DNA damage induced by irradiated tumor cells were also assessed in vitro.

RESULTS

In pre-clinical models, both RTRT and CNRT significantly inhibited primary tumor growth when compared to non-irradiated controls, with no significant difference between RTRT and CNRT. However, RTRT significantly extended survival times in mice, and increased the likelihood of inducing abscopal effects, thereby providing potential for better control of distant metastases. Further investigations revealed that the enhanced efficacy of RTRT may be attributed to the preservation of lymphocytes within the peritumoral tissue, as well as reduced damage to the surrounding skin and circulating lymphocytes. In vitro assays demonstrated that RTRT induced DNA damage and dsDNA in tumor cells, activating the cGAS-STING pathway. RTRT also triggered the release of damage-associated molecular patterns (DAMPs), which synergistically amplified the anti-tumor immune response.

CONCLUSIONS

Our findings suggested that appropriately narrowing the irradiation target volume effectively killed tumor cells while reducing damage to surrounding tissues, and preserving peritumoral lymphocytes. This approach improved the safety of radiotherapy while maintaining its efficacy in tumor control and provided an opportunity for combining high-dose radiotherapy with immunotherapy.

Syntheses, crystal structures of copper (II)-based complexes of sulfonamide derivatives and their anticancer effects through the synergistic effect of anti-angiogenesis, anti-inflammation, pro-apoptosis and cuproptosis

Three novel copper(II)-based complexes Cu-1, Cu-2, and Cu-3 containing sulfamethoxazole or sulfamethazine ligand were obtained, and their single structures were characterized. Both Cu-1 and Cu-3 show a broad spectrum of cytotoxicity than Cu-2, and Cu-1 is more cytotoxic than Cu-3. What's interesting is that Cu-1 can exhibit obvious inhibitory effect on the growth of human triple-negative breast cancer in vivo and vitro through anti-proliferative, anti-angiogenic, anti-inflammatory, pro-apoptotic and cuproptotic synergistic effects. Though Cu-3 shows no significant cytotoxicity against MDA-MB-231 cells, it can significantly inhibit the growth of SKOV3 cells in vitro by down-regulating the expression of some key proteins in the VEGF/VEGFR2 signaling pathway and the expression of some pro-inflammatory cytokines, and by disrupting the balance of intracellular reactive oxygen species levels.

Palladium-Mediated Bioorthogonal System for Prodrug Activation of N-Benzylbenzamide-Containing Tubulin Polymerization Inhibitors for the Treatment of Solid Tumors

Bioorthogonal cleavage reactions have been developed as an intriguing strategy to enhance the safety of chemotherapeutics. Aiming to reduce the toxicity and improve the targeted release properties of the colchicine binding site inhibitors (CBSIs) based on previous work, a series of biologically inert prodrugs were further designed and synthesized through a bioorthogonal prodrug strategy. The therapeutic effects of prodrugs could be "turned-on" once combined with palladium resins. Particularly, prodrug 2b was 68.3-fold less cytotoxic compared to the parent compound, while its cytotoxicity was recovered in situ in the presence of palladium resins. Mechanism studies confirmed that 2b inhibited cell growth in the same manner as CBSIs. More importantly, in vivo efficacy studies demonstrated the efficient activation of 2b by palladium resins, resulting in significant inhibition of tumor growth (63.2%). These results suggest that prodrug 2b with improved safety and targeted release property catalyzed by a Pd-mediated bioorthogonal cleavage reaction deserves further investigation.

Regulating Aggregation-Induced Emission Luminogen for Multimodal Imaging-Navigated Synergistic Therapy Involving Anti-Angiogenesis

As a new avenue for cancer research, phototheranostics has shown inexhaustible and vigorous vitality as it permits real-time diagnosis and concurrent in situ therapy upon non-invasive light-initiation. However, construction of an advanced material, allowing prominent phototheranostic outputs and synchronously surmounting the inherent deficiency of phototheranostics, would be an appealing yet significantly challenging task. Herein, an aggregation-induced emission (AIE)-active luminogen (namely DBD-TM) featured by intensive electron donor-acceptor strength and twisted architecture with finely modulated intramolecular motion, is tactfully designed and prepared. DBD-TM simultaneously possessed fluorescence emission in the second near-infrared (NIR-II) region and high-efficiency photothermal conversion. By integrating DBD-TM with anti-angiogenic agent sorafenib, a versatile nanomaterial is smoothly fabricated and utilized for trimodal imaging-navigated synergistic therapy involving photothermal therapy and anti-angiogenesis toward cancer. This advanced approach is capable of affording accurate tumor diagnosis, complete tumor elimination, and largely restrained tumor recurrence, evidently denoting a prominent theranostic formula beyond phototheranostics. This study will offer a blueprint for exploiting a new generation of cancer theranostics.

Light-Activated Anti-Vascular Combination Therapy against Choroidal Neovascularization

Choroidal neovascularization (CNV) underlies the crux of many angiogenic eye disorders. Although medications that target vascular endothelial growth factor (VEGF) are approved for treating CNV, their effectiveness in destroying new blood vessels is limited, and invasive intravitreal administration is required. Additionally, other drugs that destroy established neovessels, such as combretastatin A-4, may have systemic side effects that limit their therapeutic benefits. To overcome these shortcomings, a two-pronged anti-vascular approach is presented for CNV treatment using a photoactivatable nanoparticle system that can release a VEGF receptor inhibitor and a vascular disrupting agent when irradiated with 690 nm light. The nanoparticles can be injected intravenously to enable anti-angiogenic and vascular disrupting combination therapy for CNV through light irradiation to the eyes. This approach can potentiate therapeutic effects while maintaining a favorable biosafety profile for choroidal vascular diseases.

Longitudinal Intravascular Antibody Labeling Identified Regulatory T Cell Recruitment as a Therapeutic Target in a Mouse Model of Lung Cancer

Anticancer immunity is predicated on leukocyte migration into tumors. Once recruited, leukocytes undergo substantial reprogramming to adapt to the tumor microenvironment. A major challenge in the field is distinguishing recently recruited from resident leukocytes in tumors. In this study, we developed an intravascular Ab technique to label circulating mouse leukocytes before they migrate to tissues, providing unprecedented insight into the kinetics of recruitment. This approach unveiled the substantial role of leukocyte migration in tumor progression using a preclinical mouse model of lung adenocarcinoma. Regulatory T cells (Tregs), critical mediators of immunosuppression, were continuously and rapidly recruited into tumors throughout cancer progression. Moreover, leukocyte trafficking depended on the integrins CD11a/CD49d, and CD11a/CD49d blockade led to significant tumor burden reduction in mice. Importantly, preventing circulating Treg recruitment through depletion or sequestration in lymph nodes was sufficient to decrease tumor burden, indicating that Treg migration was crucial for suppressing antitumor immunity. These findings underscore the dynamic nature of the immune compartment within mouse lung tumors and demonstrate the relevance of a temporal map of leukocyte recruitment into tumors, thereby advancing our understanding of leukocyte migration in the context of tumor development.

Targeting vascular disrupting agent-treated tumor microenvironment with tissue-penetrating nanotherapy

Cancer treatment with vascular disrupting agents (VDAs) causes rapid and extensive necrosis in solid tumors. However, these agents fall short in eliminating all malignant cells, ultimately leading to tumor regrowth. Here, we investigated whether the molecular changes in the tumor microenvironment induced by VDA treatment sensitize the tumors for secondary nanotherapy enhanced by clinical-stage tumor penetrating peptide iRGD. Treatment of peritoneal carcinomatosis (PC) and breast cancer mice with VDA combretastatin A-4 phosphate (CA4P) resulted in upregulation of the iRGD receptors αv-integrins and NRP-1, particularly in the peripheral tumor tissue. In PC mice treated with CA4P, coadministration of iRGD resulted in an approximately threefold increase in tumor accumulation and a more homogenous distribution of intraperitoneally administered nanoparticles. Notably, treatment with a combination of CA4P, iRGD, and polymersomes loaded with a novel anthracycline Utorubicin (UTO-PS) resulted in a significant decrease in the overall tumor burden in PC-bearing mice, while avoiding overt toxicities. Our results indicate that VDA-treated tumors can be targeted therapeutically using iRGD-potentiated nanotherapy and warrant further studies on the sequential targeting of VDA-induced molecular signatures.

Peptide-IR820 Conjugate: A Promising Strategy for Efficient Vascular Disruption and Hypoxia Induction in Melanoma

Photothermal therapy (PTT) has emerged as a noninvasive and precise cancer treatment modality known for its high selectivity and lack of drug resistance. However, the clinical translation of many PTT agents is hindered by the limited biodegradability of inorganic nanoparticles and the instability of organic dyes. In this study, a peptide conjugate, IR820-Cys-Trp-Glu-Trp-Thr-Trp-Tyr (IR820-C), was designed to self-assemble into nanoparticles for both potent PTT and vascular disruption in melanoma treatment. When co-assembled with the poorly soluble vascular disrupting agent (VDA) combretastatin A4 (CA4), the resulting nanoparticles (IR820-C@CA4 NPs) accumulate efficiently in tumors, activate systemic antitumor immune responses, and effectively ablate melanoma with a single treatment and near-infrared irradiation, as confirmed by our in vivo experiments. Furthermore, by exploiting the resulting tumor hypoxia, we subsequently administered the hypoxia-activated prodrug tirapazamine (TPZ) to capitalize on the created microenvironment, thereby boosting therapeutic efficacy and antimetastatic potential. This study showcases the potential of short-peptide-based nanocarriers for the design and development of stable and efficient photothermal platforms. The multifaceted therapeutic strategy, which merges photothermal ablation with vascular disruption and hypoxia-activated chemotherapy, holds great promise for advancing the efficacy and scope of cancer treatment modalities.

Targeting the Tumor Vascular Supply to Enhance Radiation Therapy Administered in Single or Clinically Relevant Fractionated Schedules

This pre-clinical study was designed to demonstrate how vascular disrupting agents (VDAs) should be administered, either alone or when combined with radiation in clinically relevant fractionated radiation schedules, for the optimal anti-tumor effect. CDF1 mice, implanted in the right rear foot with a 200 mm3 murine C3H mammary carcinoma, were injected with various doses of the most potent VDA drug, combretastatin A-1 phosphate (CA1P), under different schedules. Tumors were also locally irradiated with single-dose, or stereotactic (3 × 5-20 Gy) or conventional (30 × 2 Gy) fractionation schedules. Tumor growth and control were the endpoints used. Untreated tumors had a tumor growth time (TGT5; time to grow to 5 times the original treatment volume) of around 6 days. This increased with increasing drug doses (5-100 mg/kg). However, with single-drug treatments, the maximum TGT5 was only 10 days, yet this increased to 19 days when injecting the drug on a weekly basis or as three treatments in one week. CA1P enhanced radiation response regardless of the schedule or interval between the VDA and radiation. There was a dose-dependent increase in radiation response when the combined with a single, stereotactic, or conventional fractionated irradiation, but these enhancements plateaued at around a drug dose of 25 mg/kg. This pre-clinical study demonstrated how VDAs should be combined with clinically applicable fractionated radiation schedules for the optimal anti-tumor effect, thus suggesting the necessary pre-clinical testing required to ultimately establish VDAs in clinical practice.

Devastating the Supply Wagons: Multifaceted Liposomes Capable of Exhausting Tumor to Death via Triple Energy Depletion

The anabolism of tumor cells can not only support their proliferation, but also endow them with a steady influx of exogenous nutrients. Therefore, consuming metabolic substrates or limiting access to energy supply can be an effective strategy to impede tumor growth. Herein, a novel treatment paradigm of starving-like therapy-triple energy-depleting therapy-is illustrated by glucose oxidase (GOx)/dc-IR825/sorafenib liposomes (termed GISLs), and such a triple energy-depleting therapy exhibits a more effective tumor-killing effect than conventional starvation therapy that only cuts off one of the energy supplies. Specifically, GOx can continuously consume glucose and generate toxic H2O2 in the tumor microenvironment (including tumor cells). After endocytosis, dc-IR825 (a near-infrared cyanine dye) can precisely target mitochondria and exert photodynamic and photothermal activities upon laser irradiation to destroy mitochondria. The anti-angiogenesis effect of sorafenib can further block energy and nutrition supply from blood. This work exemplifies a facile and safe method to exhaust the energy in a tumor from three aspects and starve the tumor to death and also highlights the importance of energy depletion in tumor treatment. It is hoped that this work will inspire the development of more advanced platforms that can combine multiple energy depletion therapies to realize more effective tumor treatment.

Nanoparticle-Mediated Drug Delivery Systems for Precision Targeting in Oncology

Nanotechnology has emerged as a transformative force in oncology, facilitating advancements in site-specific cancer therapy and personalized oncomedicine. The development of nanomedicines explicitly targeted to cancer cells represents a pivotal breakthrough, allowing the development of precise interventions. These cancer-cell-targeted nanomedicines operate within the intricate milieu of the tumour microenvironment, further enhancing their therapeutic efficacy. This comprehensive review provides a contemporary perspective on precision cancer medicine and underscores the critical role of nanotechnology in advancing site-specific cancer therapy and personalized oncomedicine. It explores the categorization of nanoparticle types, distinguishing between organic and inorganic variants, and examines their significance in the targeted delivery of anticancer drugs. Current insights into the strategies for developing actively targeted nanomedicines across various cancer types are also provided, thus addressing relevant challenges associated with drug delivery barriers. Promising future directions in personalized cancer nanomedicine approaches are delivered, emphasising the imperative for continued optimization of nanocarriers in precision cancer medicine. The discussion underscores translational research's need to enhance cancer patients' outcomes by refining nanocarrier technologies in nanotechnology-driven, site-specific cancer therapy.

Self-assembled nanomicelles for oral delivery of luteolin utilizing the intestinal lymphatic pathway to target pancreatic cancer

Pancreatic cancer is one of the major cause of cancer-related deaths worldwide, and is mainly associated with carcinomas of the pancreatic tissue. Current therapies for treating pancreatic cancer have a major drawback related to their low bioavailability and non-specificity, which leads to low therapeutic efficacy and side effects. Luteolin (LUT) has been clinically used for treatment of various types of cancer, although its clinical use has declined owing to its low oral bioavailability. In this work, we prepared an effervescent-based nanocarrier (NG) that rapidly triggers an effervescent reaction and transforms into nanomicelles to modulate the oral bioavailability of the hydrophobic drug Luteolin (LUT). Furthermore, we performed tests to assess its in vitro epithelial cell permeability and cellular internalization on a Caco-2 monolayer. We also performed in vivo toxicity assessment using animal models. Further, we evaluated the nanocarrier system's in vivo efficacy in tumor xenograft pancreatic cancer models. We validated that being pH responsive, our effervescent carrier disassembles at intestinal pH and is absorbed through the intestinal lymphatic system (ILS) to further site-specifically invade the pancreatic cancer cells. Furthermore, the negative surface charge and particle size (450 ± 100 nm) of the nanomicelles helped to internalize LUT through the ILS. We observed that LUT-loaded nanomicelles have significant antipancreatic cancer efficacy by activating caspase-3 activity and downregulating VEGF-A, FAK, TNF-α, and Ki-67. Unlike other drug-delivery systems, we developed noninvasive nanocarrier system has the capability of transporting the hydrophobic drug LUT from the intestine to the tumor site by utilizing the ILS.

Natural Products as Regulators against Matrix Metalloproteinases for the Treatment of Cancer

Cancers are currently the major cause of mortality in the world. According to previous studies, matrix metalloproteinases (MMPs) have an impact on tumor cell proliferation, which could lead to the onset and progression of cancers. Therefore, regulating the expression and activity of MMPs, especially MMP-2 and MMP-9, could be a promising strategy to reduce the risk of cancers. Various studies have tried to investigate and understand the pathophysiology of cancers to suggest potent treatments. In this review, we summarize how natural products from marine organisms and plants, as regulators of MMP-2 and MMP-9 expression and enzymatic activity, can operate as potent anticancer agents.

New antiproliferative 3-substituted oxindoles inhibiting EGFR/VEGFR-2 and tubulin polymerization

New 3-substituted oxindole derivatives were designed and synthesized as antiproliferative agents. The antiproliferative activity of compounds 6a-j was evaluated against 60 NCI cell lines. Among these tested compounds, compounds 6f and 6g showed remarkable antiproliferative activity, specifically against leukemia and breast cancer cell lines. Compound 6f was the most promising antiproliferative agent against MCF-7 (human breast cancer) with an IC50 value of 14.77 µM compared to 5-fluorouracil (5FU) (IC50 = 2.02 µM). Notably, compound 6f hampered receptor tyrosine EGFR fundamentally with an IC50 value of 1.38 µM, compared to the reference sunitinib with an IC50 value of 0.08 µM. Moreover, compound 6f afforded anti-tubulin polymerization activity with an IC50 value of 7.99 µM as an outstanding observable activity compared with the reference combretastatin A4 with an IC50 value of 2.64 µM. In silico molecular-docking results of compound 6f in the ATP-binding site of EGFR agreed with the in vitro results. Besides, the investigation of the physicochemical properties of compound 6f via the egg-boiled method clarified good lipophilicity, GIT absorption, and blood-brain barrier penetration properties.

Synchronous Intravital Imaging and Cavitation Monitoring of Antivascular Focused Ultrasound in Tumor Microvasculature Using Monodisperse Low Boiling Point Nanodroplets

Focused ultrasound-stimulated microbubbles can induce blood flow shutdown and ischemic necrosis at higher pressures in an approach termed antivascular ultrasound. Combined with conventional therapies of chemotherapy, immunotherapy, and radiation therapy, this approach has demonstrated tumor growth inhibition and profound synergistic antitumor effects. However, the lower cavitation threshold of microbubbles can potentially yield off-target damage that the polydispersity of clinical agent may further exacerbate. Here we investigate the use of a monodisperse nanodroplet formulation for achieving antivascular effects in tumors. We first develop stable low boiling point monodisperse lipid nanodroplets and examine them as an alternative agent to mediate antivascular ultrasound. With synchronous intravital imaging and ultrasound monitoring of focused ultrasound-stimulated nanodroplets in tumor microvasculature, we show that nanodroplets can trigger blood flow shutdown and do so with a sharper pressure threshold and with fewer additional events than conventionally used microbubbles. We further leverage the smaller size and prolonged pharmacokinetic profile of nanodroplets to allow for potential passive accumulation in tumor tissue prior to antivascular ultrasound, which may be a means by which to promote selective tumor targeting. We find that vascular shutdown is accompanied by inertial cavitation and complex-order sub- and ultraharmonic acoustic signatures, presenting an opportunity for effective feedback control of antivascular ultrasound.

Synthesis and biological evaluation of structurally diverse 6-aryl-3-aroyl-indole analogues as inhibitors of tubulin polymerization

The synthesis and evaluation of small-molecule inhibitors of tubulin polymerization remains a promising approach for the development of new therapeutic agents for cancer treatment. The natural products colchicine and combretastatin A-4 (CA4) inspired significant drug discovery campaigns targeting the colchicine site located on the beta-subunit of the tubulin heterodimer, but so far these efforts have not yielded an approved drug for cancer treatment in human patients. Interest in the colchicine site was enhanced by the discovery that a subset of colchicine site agents demonstrated dual functionality as both potent antiproliferative agents and effective vascular disrupting agents (VDAs). Our previous studies led to the discovery and development of a 2-aryl-3-aroyl-indole analogue (OXi8006) that inhibited tubulin polymerization and demonstrated low nM IC50 values against a variety of human cancer cell lines. A water-soluble phosphate prodrug salt (OXi8007), synthesized from OXi8006, displayed promising vascular disrupting activity in mouse models of cancer. To further extend structure-activity relationship correlations, a series of 6-aryl-3-aroyl-indole analogues was synthesized and evaluated for their inhibition of tubulin polymerization and cytotoxicity against human cancer cell lines. Several structurally diverse molecules in this small library were strong inhibitors of tubulin polymerization and of MCF-7 and MDA-MB-231 human breast cancer cells. One of the most promising analogues (KGP591) caused significant G2/M arrest of MDA-MB-231 cells, disrupted microtubule structure and cell morphology in MDA-MB-231 cells, and demonstrated significant inhibition of MDA-MB-231 cell migration in a wound healing (scratch) assay. A phosphate prodrug salt, KGP618, synthesized from its parent phenolic precursor, KGP591, demonstrated significant reduction in bioluminescence signal when evaluated in vivo against an orthotopic model of kidney cancer (RENCA-luc) in BALB/c mice, indicative of VDA efficacy. The most active compounds from this series offer promise as anticancer therapeutic agents.

Regulation of Angiogenesis by Non-Coding RNAs in Cancer

Non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, have been identified as crucial regulators of various biological processes through epigenetic regulation, transcriptional regulation, and post-transcriptional regulation. Growing evidence suggests that dysregulation and activation of non-coding RNAs are closely associated with tumor angiogenesis, a process essential for tumor growth and metastasis and a major contributor to cancer-related mortality. Therefore, understanding the molecular mechanisms underlying tumor angiogenesis is of utmost importance. Numerous studies have documented the involvement of different types of non-coding RNAs in the regulation of angiogenesis. This review provides an overview of how non-coding RNAs regulate tumor angiogenesis. Additionally, we discuss emerging strategies that exploit non-coding RNAs for anti-angiogenic therapy in cancer treatment. Ultimately, this review underscores the crucial role played by non-coding RNAs in tumor angiogenesis and highlights their potential as therapeutic targets for anti-angiogenic interventions against cancer.

Everolimus Acts in Synergy with Vinorelbine to Suppress the Growth of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a challenging cancer to treat, as traditional chemotherapies have shown limited effectiveness. The mammalian target of rapamycin/sirolimus (mTOR) and microtubules are prominent druggable targets for HCC. In this study, we demonstrated that co-targeting mTOR using mTOR inhibitors (everolimus and sirolimus) along with the microtubule inhibitor vinorelbine yielded results superior to those of the monotherapies in HCC PDX models. Our research showed that the vinorelbine arrests cells at the mitotic phase, induces apoptosis, and normalizes tumor blood vessels but upregulates survivin and activates the mTOR/p70S6K/4EBP1 pathway. The addition of the everolimus significantly improved the tumor response to the vinorelbine, leading to improved overall survival (OS) in most tested orthotopic HCC PDX models. The mechanistic investigation revealed that this marked antitumor effect was accompanied by the downregulations of mTOR targets (p-p70S6K, p-4EBP1, and p-S6K); several key cell-cycle regulators; and the antiapoptotic protein survivin. These effects did not compromise the normalization of the blood vessels observed in response to the vinorelbine in the vinorelbine-sensitive PDX models or to the everolimus in the everolimus-sensitive PDX models. The combination of the everolimus and vinorelbine (everolimus/vinorelbine) also promoted apoptosis with minimal toxicity. Given the cost-effectiveness and established effectiveness of everolimus, and especially sirolimus, this strategy warrants further investigation in early-phase clinical trials.

Multifunctional nano MOF drug delivery platform in combination therapy

Recent preclinical and clinical studies have demonstrated that for cancer treatment, combination therapies are more effective than monotherapies in reducing drug-related toxicity, decreasing drug resistance, and improving therapeutic efficacy. With the rapid development of nanotechnology, the combination of metal-organic frameworks (MOFs) and multi-mode therapy offers a realistic possibility to further improve the shortcomings of cancer treatment. This article focuses on the latest developments, achievements, and treatment strategies of representative multifunctional MOF combination therapies for cancer treatment in recent years, which include not only bimodal combination therapies, but also multi-modal synergistic therapies, further demonstrating the effectiveness and superiority of the MOF drug delivery systems in cancer treatment.

pH-Responsive NIR-II phototheranostic agents for in situ tumor vascular monitoring and combined anti-vascular/photothermal therapy

Developing nanoplatforms integrating superior fluorescence imaging ability in second near-infrared (NIR-II) window and tumor microenvironment responsive multi-modal therapy holds great potential for real-time feedback of therapeutic efficacy and optimizing tumor inhibition. Herein, we developed a pH-sensitive pyrrolopyrrole aza-BODIPY-based amphiphilic molecule (PTG), which has a balanced NIR-II fluorescence brightness and photothermal effect. PTG is further co-assembled with a vascular disrupting agent (known as DMXAA) to prepare PTDG nanoparticles for combined anti-vascular/photothermal therapy and real-time monitoring of the tumor vascular disruption. Each PTG molecule has an active PT-3 core which is linked to two PEG chains via pH-sensitive ester bonds. The cleavage of ester bonds in the acidic tumor environment would tricker releases of DMXAA for anti-vascular therapy and further assemble PT-3 cores into micrometer particles for long term monitoring of the tumor progression. Furthermore, benefiting from the high brightness in the NIR-II region (119.61 M-1 cm-1) and long blood circulation time (t1/2 = 235.6 min) of PTDG nanoparticles, the tumor vascular disrupting process can be in situ visualized in real time during treatment. Overall, this study demonstrates a self-assembly strategy to build a pH-responsive NIR-II nanoplatform for real-time monitoring of tumor vascular disruption, long-term tracking tumor progression and combined anti-vascular/photothermal therapy.

Preparation and Characterization Evaluation of Poly(L-Glutamic Acid)-g-Methoxy Poly(Ethylene Glycol)/Combretastatin A4/BLZ945 Nanoparticles for Cervical Cancer Therapy

Purpose

Cervical cancer (CC) is a highly vascularized tumor with abundant abnormal blood vessel, which could be targeted by therapeutic strategies. Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) have shown great potential as nano vascular disrupting agents (VDAs) in the realm of synergistic cancer therapy.

Methods

In this study, we investigated the nanocharacteristics of CB-NPs, focusing on active pharmaceutical ingredients (API), as well as lyophilized samples combining API with protective agents (PAs). The in vivo efficacy of final sample (API + PAs) was evaluated.

Results

The assembled sphere of API with complex core and thin-shell structure was confirmed. PAs were found to significantly influence in vivo efficacy. Collaborative efforts between API and PAs, namely mannitol and lactose, resulted in the most promising lyophilized sample, ie, the final sample (FS2) for CC therapy. Impressively, FS2 demonstrated an exceptional 100% cure rate on the CC U14-bearing mice model.

Conclusion

FS2 has provided significant insights for cervical cancer therapy. It is also crucial to develop a comprehensive evaluation strategy for the formulation of nanomedicine, which has the potential to serve as a guideline for future clinical trials.

IKBKE regulates angiogenesis by modulating VEGF expression and secretion in glioblastoma

PURPOSE

As a noncanonical inflammatory kinase, IKBKE is frequently overexpressed and activated and has been identified as an oncogenic protein in glioblastoma. However, the potential function and underlying mechanism of IKBKE contributing to tumor angiogenesis remain elusive.

METHODS

First, we analyzed the correlation between IKBKE and VEGF expression in glioma samples by immunohistochemistry (IHC). Second, HUVEC-related assays and Western blot were used to detect the regulatory effect of IKBKE on angiogenesis by modulating VEGF expression. Third, IKBKE depletion could alleviate the influence of VEGF expression on IHC of intracranial glioma model.

RESULTS

We demonstrate that depletion of IKBKE markedly inhibits tumor growth and angiogenesis in glioblastoma. Mechanistically, IKBKE induces VEGF expression and secretion by regulating AKT/FOXO3a in glioblastoma.

CONCLUSIONS

This study reveals that IKBKE is a novel oncogenic molecule that induces angiogenesis through the promotion of VEGF expression and highlights the potential of targeting IKBKE for glioblastoma therapy.

Structure Guided Design, Synthesis, and Biological Evaluation of Oxetane-Containing Indole Analogues

The oxetane functional group offers a variety of potential advantages when incorporated within appropriate therapeutic agents as a ketone surrogate. OXi8006, a 2-aryl-3-aroyl-indole analogue, functions as a small-molecule inhibitor of tubulin polymerization that has a dual mechanism of action as both an antiproliferative agent and a tumor-selective vascular disrupting agent. Replacement of the bridging ketone moiety in OXi8006 with an oxetane functional group has expanded structure activity relationship (SAR) knowledge and provided insights regarding oxetane incorporation within this class of molecules. A new synthetic method using an oxetane-containing tertiary alcohol subjected to Lewis acid catalyzed conditions led to successful Friedel-Crafts alkylation and yielded fourteen new oxetane-containing indole-based molecules. This synthetic approach represents the first method to successfully install an oxetane ring at the 3-position of a 2-aryl-indole system. Several analogues showed potent cytotoxicity (micromolar GI50 values) against human breast cancer cell lines (MCF-7 and MDA-MB-231) and a pancreatic cancer cell line (PANC-1), although they proved to be ineffective as inhibitors of tubulin polymerization. Molecular docking studies comparing colchicine with the OXi8006-oxetane analogue 5m provided a rationale for the differential interaction of these molecules with the colchicine site on the tubulin heterodimer.

An Intelligent Vascular Disrupting Dendritic Nanodevice Incorporating Copper Sulfide Nanoparticles for Immune Modulation-Mediated Combination Tumor Therapy

Development of intelligent nanoplatforms that can simultaneously target multiple factors associated with tumor growth and metastasis remains an extreme challenge. Here, an intelligent dendritic nanodevice incorporating both copper sulfide nanoparticles (CuS NPs) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA, a vascular disrupting agent) within the dendrimer internal cavities and surface modified with a targeting agent LyP-1 peptide is reported. The resulting generation 5 (G5) dendrimer-based nanodevice, known as G5-PEG-LyP-1-CuS-DMXAA NPs (GLCD NPs), possess good colloidal stability, pH-sensitive drug release kinetics, and high photothermal conversion efficiency (59.3%). These functional GLCD NPs exert a LyP-1-targeted killing effect on breast tumors by combining CuS-mediated photothermal therapy (PTT) and DMXAA-induced vascular disruption, while also triggering antitumor immune responses through PTT-induced immunogenic cell death and DMXAA-mediated immune regulation via M1 polarization of tumor-associated macrophages and dendritic cell maturation. In addition, with the LyP-1-mediated proapoptotic activity, the GLCD NPs can specifically kill tumor lymphatic endothelial cells. The simultaneous disruption of tumor blood vessels and lymphatic vessels cuts off the two main pathways of tumor metastasis, which plays a two-pronged role in inhibiting lung metastasis of the breast cancer model. Thus, the developed GLCD NPs represent an advanced intelligent nanoformulation for immune modulation-mediated combination tumor therapy with potential for clinical translations.

Flagella of Tumor-Targeting Bacteria Trigger Local Hemorrhage to Reprogram Tumor-Associated Macrophages for Improved Antitumor Therapy

Tumor-associated macrophages (TAMs) exhibit an immunosuppressive M2 phenotype and lead to failure of antitumor therapy. Infiltrated erythrocytes during hemorrhage are recognized as a promising strategy for polarizing TAMs. However, novel materials that precisely induce tumor hemorrhage without affecting normal coagulation still face challenges. Here, tumor-targeting bacteria (flhDC VNP) are genetically constructed to realize precise tumor hemorrhage. FlhDC VNP colonizes the tumor and overexpresses flagella during proliferation. The flagella promote the expression of tumor necrosis factor α, which induces local tumor hemorrhage. Infiltrated erythrocytes during the hemorrhage temporarily polarize macrophages to the M1 subtype. In the presence of artesunate, this short-lived polarization is transformed into a sustained polarization because artesunate and heme form a complex that continuously produces reactive oxygen species. Therefore, the flagella of active tumor-targeting bacteria may open up new strategies for reprogramming TAMs and improving antitumor therapy.

Antiproliferative and Tubulin-Destabilising Effects of 3-(Prop-1-en-2-yl)azetidin-2-Ones and Related Compounds in MCF-7 and MDA-MB-231 Breast Cancer Cells

A series of novel 3-(prop-1-en-2-yl)azetidin-2-one, 3-allylazetidin-2-one and 3-(buta-1,3-dien-1-yl)azetidin-2-one analogues of combretastatin A-4 (CA-4) were designed and synthesised as colchicine-binding site inhibitors (CBSI) in which the ethylene bridge of CA-4 was replaced with a β-lactam (2-azetidinone) scaffold. These compounds, together with related prodrugs, were evaluated for their antiproliferative activity, cell cycle effects and ability to inhibit tubulin assembly. The compounds demonstrated significant in vitro antiproliferative activities in MCF-7 breast cancer cells, particularly for compounds 9h, 9q, 9r, 10p, 10r and 11h, with IC₅₀ values in the range 10-33 nM. These compounds were also potent in the triple-negative breast cancer (TBNC) cell line MDA-MB-231, with IC₅₀ values in the range 23-33 nM, and were comparable with the activity of CA-4. The compounds inhibited the polymerisation of tubulin in vitro, with significant reduction in tubulin polymerization, and were shown to interact at the colchicine-binding site on tubulin. Flow cytometry demonstrated that compound 9q arrested MCF-7 cells in the G₂/M phase and resulted in cellular apoptosis. The antimitotic properties of 9q in MCF-7 human breast cancer cells were also evaluated, and the effect on the organization of microtubules in the cells after treatment with compound 9q was observed using confocal microscopy. The immunofluorescence results confirm that β-lactam 9q is targeting tubulin and resulted in mitotic catastrophe in MCF-7 cells. In silico molecular docking supports the hypothesis that the compounds interact with the colchicine-binding domain of tubulin. Compound 9q is a novel potent microtubule-destabilising agent with potential as a promising lead compound for the development of new antitumour agents.

Light-Driven Self-Recruitment of Biomimetic Semiconducting Polymer Nanoparticles for Precise Tumor Vascular Disruption

Tumor vascular disrupting therapy has offered promising opportunities to treat cancer in clinical practice, whereas the overall therapeutic efficacy is notably limited due to the off-target effects and repeated dose toxicity of vascular disrupting agents (VDAs). To tackle this problem, a VDA-free biomimetic semiconducting polymer nanoparticle (SPN_P ) is herein reported for precise tumor vascular disruption through two-stage light manipulation. SPN_P consists of a semiconducting polymer nanoparticle as the photothermal agent camouflaged with platelet membranes that specifically target disrupted vasculature. Upon the first photoirradiation, SPN_P administered in vivo generates mild hyperthermia to trigger tumor vascular hemorrhage, which activates the coagulation cascade and recruits more SPN_P to injured blood vessels. Such enhanced tumor vascular targeting of photothermal agents enables intense hyperthermia to destroy the tumor vasculature during the second photoirradiation, leading to complete tumor eradication and efficient metastasis inhibition. Intriguingly, the mechanism study reveals that this vascular disruption strategy alleviates splenomegaly and reverses the immunosuppressive tumor microenvironment by reducing myeloid-derived suppressor cells. Therefore, this study not only illustrates a light-driven self-recruitment strategy to enhance tumor vascular disruption via a single dose of biomimetic therapeutics but also deciphers the immunotherapeutic role of vascular disruption therapy that is conducive to clinical studies.

Radioenhancement with the Combination of Docetaxel and Ultrasound Microbubbles: In Vivo Prostate Cancer

Using an in vitro prostate cancer model, we previously demonstrated the significant enhancement of radiotherapy (XRT) with the combined treatment of docetaxel (Taxotere; TXT) and ultrasound-microbubbles (USMB). Here, we extend these findings to an in vivo cancer model. Severe combined immune-deficient male mice were xenografted with the PC-3 prostate cancer cell line in the hind leg and treated with USMB, TXT, radiotherapy (XRT), and their combinations. The tumors were imaged with ultrasound pre-treatment and 24 h post-treatment, following which they were extracted for the histological analysis of the tumor-cell death (D_N; H&E) and apoptosis (D_A; TUNEL). The tumors' growths were assessed for up to ~6 weeks and analysed using the exponential Malthusian tumor-growth model. The tumors' doubling time (V_T) was characterized as growth (positive) or shrinkage (negative). The cellular death and apoptosis increased ~5-fold with the TXT + USMB + XRT (D_n = 83% and D_a = 71%) compared to the XRT alone (D_n = 16% and D_a = 14%), and by ~2-3-fold with the TXT + XRT (D_n = 50% and D_a = 38%) and USMB + XRT (D_n = 45% and D_a = 27%) compared to the XRT. The USMB enhanced the cellular bioeffects of the TXT by ~2-5-fold with the TXT + USMB (D_n = 42% and D_a = 50%), compared with the TXT alone (D_n = 19% and D_a = 9%). The USMB alone caused cell death (D_n = 17% and D_a = 10%) compared to the untreated control (D_n = 0.4% and D_a = 0%). The histological cellular bioeffects were correlated with the changes in the ultrasound RF mid-band-fit data, which were associated with the cellular morphology. The linear regression analysis displayed a positive linear correlation between the mid-band fit and the overall cell death (R² = 0.9164), as well as a positive linear correlation between the mid-band fit and the apoptosis (R² = 0.8530). These results demonstrate a correlation between the histological and spectral measurements of the tissue microstructure and that cellular morphological changes can be detected by ultrasound scattering analysis. In addition, the tumor volumes from the triple-combination treatment were significantly smaller than those from the control, XRT, USMB + XRT, and TXT + XRT, from day 2 onward. The TXT + USMB + XRT-treated tumors shrank from day 2 and at each subsequent time-point measured (V_T ~-6 days). The growth of the XRT-treated tumors was inhibited during the first 16 days, following which the tumors grew (V_T ~9 days). The TXT + XRT and USMB + XRT groups displayed an initial decrease in tumor size (day 1-14; TXT + XRT V_T ~-12 days; USMB + XRT V_T ~-33 days), followed by a growth phase (day 15-37; TXT + XRT V_T ~11 days; USMB + XRT V_T ~22 days). The triple-combination therapy induced tumor shrinkage to a greater extent than any of the other treatments. This study demonstrates the in vivo radioenhancement potential of chemotherapy combined with therapeutic ultrasound-microbubble treatment in inducing cell death and apoptosis, as well as long-term tumor shrinkage.

BODIPY as a Multifunctional Theranostic Reagent in Biomedicine: Self-Assembly, Properties, and Applications

The use of boron dipyrromethene (BODIPY) in biomedicine is reviewed. To open, its synthesis and regulatory strategies are summarized, and inspiring cutting-edge work in post-functionalization strategies is highlighted. A brief overview of assembly model of BODIPY is then provided: BODIPY is introduced as a promising building block for the formation of single- and multicomponent self-assembled systems, including nanostructures suitable for aqueous environments, thereby showing the great development potential of supramolecular assembly in biomedicine applications. The frontier progress of BODIPY in biomedical application is thereafter described, supported by examples of the frontiers of biomedical applications of BODIPY-containing smart materials: it mainly involves the application of materials based on BODIPY building blocks and their assemblies in fluorescence bioimaging, photoacoustic imaging, disease treatment including photodynamic therapy, photothermal therapy, and immunotherapy. Lastly, not only the current status of the BODIPY family in the biomedical field but also the challenges worth considering are summarized. At the same time, insights into the future development prospects of biomedically applicable BODIPY are provided.

Design, Synthesis, and Biological Evaluation of Pyrimidine Dihydroquinoxalinone Derivatives as Tubulin Colchicine Site-Binding Agents That Displayed Potent Anticancer Activity Both In Vitro and In Vivo

Polymerization of tubulin dimers to form microtubules is one of the key events in cell proliferation. The inhibition of this event has long been recognized as a potential treatment option for various types of cancer. Compound 1e was previously developed by our team as a potent inhibitor of tubulin polymerization that binds to the colchicine site. To further improve the potency and therapeutic properties of compound 1e, we hypothesized based on the X-ray crystal structure that modification of the pyrimidine dihydroquinoxalinone scaffold with additional hetero-atom (N, O, and S) substituents could allow the resulting new compounds to bind more tightly to the colchicine site and display greater efficacy in cancer therapy. We therefore synthesized a series of new pyrimidine dihydroquinoxalinone derivatives, compounds 10, 12b-c, 12e, 12h, and 12j-l, and evaluated their cytotoxicity and relative ability to inhibit proliferation, resulting in the discovery of new tubulin-polymerization inhibitors. Among these, the most potent new inhibitor was compound 12k, which exhibited high cytotoxic activity in vitro, a longer half-life than the parental compound in liver microsomes (IC50 = 0.2 nM, t 1/2 = >300 min), and significant potency against a wide range of cancer cell lines including those from melanoma and breast, pancreatic, and prostate cancers. High-resolution X-ray crystal structures of the best compounds in this scaffold series, 12e, 12j, and 12k, confirmed their direct binding to the colchicine site of tubulin and revealed their detailed molecular interactions. Further evaluation of 12k in vivo using a highly taxane-resistant prostate cancer xenograft model, PC-3/TxR, demonstrated the strong tumor growth inhibition at the low dose of 2.5 mg/kg (i.v., twice per week). Collectively, these results strongly support further preclinical evaluations of 12k as a potential candidate for development.

Design, Synthesis, and Biological Evaluation of Heterocyclic-Fused Pyrimidine Chemotypes Guided by X-ray Crystal Structure with Potential Antitumor and Anti-multidrug Resistance Efficacy Targeting the Colchicine Binding Site

Herein, a series of quinazoline and heterocyclic fused pyrimidine analogues were designed and synthesized based on the X-ray co-crystal structure of lead compound 3a, showing efficacious antitumor activities. Two analogues, 15 and 27a, exhibited favorable antiproliferative activities, which were more potent than lead compound 3a by 10-fold in MCF-7 cells. In addition, 15 and 27a exhibited potent antitumor efficacy and tubulin polymerization inhibition in vitro. 15 reduced the average tumor volume by 80.30% (2 mg/kg) in the MCF-7 xenograft model and 75.36% (4 mg/kg) in the A2780/T xenograft model, respectively. Most importantly, supported by structural optimization and Mulliken charge calculation, X-ray co-crystal structures of compounds 15, 27a, and 27b in complex with tubulin were resolved. In summary, our research provided the rational design strategy of colchicine binding site inhibitors (CBSIs) based on X-ray crystallography with antiproliferation, antiangiogenesis, and anti-multidrug resistance properties.

Overcoming chemoresistance in non-angiogenic colorectal cancer by metformin via inhibiting endothelial apoptosis and vascular immaturity

The development of chemoresistance which results in a poor prognosis often renders current treatments for colorectal cancer (CRC). In this study, we identified reduced microvessel density (MVD) and vascular immaturity resulting from endothelial apoptosis as therapeutic targets for overcoming chemoresistance. We focused on the effect of metformin on MVD, vascular maturity, and endothelial apoptosis of CRCs with a non-angiogenic phenotype, and further investigated its effect in overcoming chemoresistance. In situ transplanted cancer models were established to compare MVD, endothelial apoptosis and vascular maturity, and function in tumors from metformin- and vehicle-treated mice. An in vitro co-culture system was used to observe the effects of metformin on tumor cell-induced endothelial apoptosis. Transcriptome sequencing was performed for genetic screening. Non-angiogenic CRC developed independently of angiogenesis and was characterized by vascular leakage, immaturity, reduced MVD, and non-hypoxia. This phenomenon had also been observed in human CRC. Furthermore, non-angiogenic CRCs showed a worse response to chemotherapeutic drugs in vivo than in vitro. By suppressing endothelial apoptosis, metformin sensitized non-angiogenic CRCs to chemo-drugs via elevation of MVD and improvement of vascular maturity. Further results showed that endothelial apoptosis was induced by tumor cells via activation of caspase signaling, which was abrogated by metformin administration. These findings provide pre-clinical evidence for the involvement of endothelial apoptosis and subsequent vascular immaturity in the chemoresistance of non-angiogenic CRC. By suppressing endothelial apoptosis, metformin restores vascular maturity and function and sensitizes CRC to chemotherapeutic drugs via a vascular mechanism.

Unraveling the Synergy between Atezolizumab and Bevacizumab for the Treatment of Hepatocellular Carcinoma

Tyrosine kinase inhibitors (TKIs) with antiangiogenic properties, such as sorafenib, have been the standard choice to systemically treat hepatocellular carcinoma for over a decade. More recently, encouraging results were obtained using immune checkpoint inhibitors, although head-to-head comparisons with sorafenib in phase 3 trials could not demonstrate superiority in terms of overall survival. The IMbrave150 was a breakthrough study that resulted in atezolizumab/bevacizumab, a combination of an antiangiogenic and an immune checkpoint inhibitor, as a new standard of care for advanced HCC. This review discusses the mode of action, clinical efficacy, and biomarker research for both drug classes and for the combination therapy. Moreover, the synergy between atezolizumab and bevacizumab is highlighted, unraveling pathophysiological mechanisms underlying an enhanced anticancer immunity by changing the immunosuppressed to a more immunoreactive tumor microenvironment (TME). This is achieved by upregulation of antigen presentation, upregulation of T-cell proliferation, trafficking and infiltration, impairing recruitment, and proliferation of immunosuppressive cells in the TME. However, more insights are needed to identify biomarkers of response that may improve patient selection and outcome.

Engineering the Tumor Immune Microenvironment through Minimally Invasive Interventions

The tumor microenvironment (TME) is a unique landscape that poses several physical, biochemical, and immune barriers to anti-cancer therapies. The rapidly evolving field of immuno-engineering provides new opportunities to dismantle the tumor immune microenvironment by efficient tumor destruction. Systemic delivery of such treatments can often have limited local effects, leading to unwanted offsite effects such as systemic toxicity and tumor resistance. Interventional radiologists use contemporary image-guided techniques to locally deliver these therapies to modulate the immunosuppressive TME, further accelerating tumor death and invoking a better anti-tumor response. These involve local therapies such as intratumoral drug delivery, nanorobots, nanoparticles, and implantable microdevices. Physical therapies such as photodynamic therapy, electroporation, hyperthermia, hypothermia, ultrasound therapy, histotripsy, and radiotherapy are also available for local tumor destruction. While the interventional radiologist can only locally manipulate the TME, there are systemic offsite recruitments of the immune response. This is known as the abscopal effect, which leads to more significant anti-tumoral downstream effects. Local delivery of modern immunoengineering methods such as locoregional CAR-T therapy combined with immune checkpoint inhibitors efficaciously modulates the immunosuppressive TME. This review highlights the various advances and technologies available now to change the TME and revolutionize oncology from a minimally invasive viewpoint.

Assessment of Cardiotoxicity after a Single Dose of Combretastatin A4-Phosphate in Dogs Using Two-Dimensional Speckle-Tracking Echocardiography

Simple Summary

Combretastatin A4-phosphate is a chemotherapeutic drug which has been evaluated for treatment of solid canine tumors. Previous studies reported cardiotoxic effects based on changes in cardiac troponin I measurements, blood pressure, and electrocardiography. We evaluated the cardiotoxic effect by two-dimensional speckle tracking echocardiography. This advanced imaging technique analyzes global and regional myocardial function and is used as the gold-standard for the assessment of cardiac function in human patients receiving chemotherapy. We found that certain strain measurements were significantly decreased 24 h after the administration of combretastatin A4-phosphate and that these changes were correlated with an increase in cardiac troponin I. Our results suggest that two-dimensional speckle tracking may be useful for the early detection of cardiac dysfunction in canine cancer patients as well as promising during follow-up.

Abstract

Combretastatin A4-phosphate (CA4P) is a vascular disrupting agent that was recently described for the treatment of solid canine tumors. Conventional echocardiography and pulsed wave tissue Doppler imaging did not reveal cardiotoxicity in dogs, however, the gold standard for assessing myocardial damage in humans receiving cardiotoxic chemotherapeutics is two-dimensional speckle-tracking echocardiography. The current study evaluated the cardiotoxic effect of a single dose of CA4P in dogs using peak systolic strain measurements and the variability of these measurements. Echocardiographic examinations of seven healthy beagles and five canine cancer patients that received CA4P were retrospectively reviewed. Peak systolic regional longitudinal strain (LSt), peak systolic regional circumferential strain (CSt), and peak systolic regional radial strain (RSt) were measured before and 24 h after administration of CA4P. Peak systolic strain measurements were compared to serum cardiac troponin I (cTnI). To quantify intra- and inter-observer measurement variability, seven echocardiographic examinations were selected and each strain parameter was measured by three observers on three consecutive days. After CA4P administration, the median LSt and CSt values decreased by 21.8% (p = 0.0005) and 12.3% (p = 0.002), respectively, whereas the median RSt values were not significantly different (p = 0.70). The decrease in LSt was correlated with increased serum cTnI values (Spearman rho = −0.64, p = 0.02). The intra-observer coefficients of variation (CV) were 9%, 4%, and 13% for LSt, CSt, and RSt, respectively, while the corresponding interobserver CVs were 11%, 12%, and 20%. Our results suggest that regional peak systolic strain measurements may be useful for the early detection of cardiotoxicity that is caused by vascular disrupting agents and that LSt may be promising for the follow-up of canine cancer patients.

Recent advances in bacterial therapeutics based on sense and response

Intelligent drug delivery is a promising strategy for cancer therapies. In recent years, with the rapid development of synthetic biology, some properties of bacteria, such as gene operability, excellent tumor colonization ability, and host-independent structure, make them ideal intelligent drug carriers and have attracted extensive attention. By implanting condition-responsive elements or gene circuits into bacteria, they can synthesize or release drugs by sensing stimuli. Therefore, compared with traditional drug delivery, the usage of bacteria for drug loading has better targeting ability and controllability, and can cope with the complex delivery environment of the body to achieve the intelligent delivery of drugs. This review mainly introduces the development of bacterial-based drug delivery carriers, including mechanisms of bacterial targeting to tumor colonization, gene deletions or mutations, environment-responsive elements, and gene circuits. Meanwhile, we summarize the challenges and prospects faced by bacteria in clinical research, and hope to provide ideas for clinical translation.

A self-activating nanoized vascular disrupting agent for selective anti-tumor therapy

Vascular disrupting agents (VDAs) have great potential in antitumor therapy, while the efficiency is limited by cardiovascular toxicity. In this study, a self-activating nanoized plinabulin (poly (_l-glutamic acid) grafted Azo-Plinabulin, AzoP-NP) was constructed. The AzoP-NPs can selectively be activated to an amino derivative of plinabulin (AmP) by intrinsic tumor hypoxia, disrupting tumor vessels and amplifying hypoxia, whilst be activated by self-amplified tumor hypoxia, then selectively inhibit tumor growth. In 4T1 tumor model, the AzoP-NPs had a selective biodistribution in tumor, as the free AmP in tumors at 24 h after AzoP-NPs treatment was 18.6 fold of that after AmP treatment and significantly higher than that in other tissues. Accordingly, AzoP-NPs resulted in no obvious acute cardiovascular toxicity (plasma von Willebrand factor in PBS, AzoP-NPs and AmP group: 143.1, 184.0 and 477.6 ng/mL) and a significantly stronger tumor inhibition than AmP. And the sustained release of drug in AzoP-NPs led to a higher maximum tolerated dose (MTD) (MTD of AzoP-NPs and AmP: > 80 vs 20 mg/kg). In addition, AzoP-NPs amplified tumor hypoxic, and synergized the anti-tumor effect of Tirapazamine (TPZ), a hypoxia-activated drug in clinical trials, with an inhibition rate of 97.7% and Q value of 1.89. Therefore, our findings provide new insights into next generation VDAs and their application in tumor therapy.

Enhancing Doxorubicin Delivery in Solid Tumor by Superhydrophobic Amorphous Calcium Carbonate-Doxorubicin Silica Nanoparticles with Focused Ultrasound

The current approach of delivering chemotherapy via pH-sensitive amorphous calcium carbonate-doxorubicin silica nanoparticles (ADS NPs) faces the challenge of insufficient drug dose due to drug instability within the bloodstream and poor tumor penetration. To overcome these long-standing obstacles, we proposed a superhydrophobic coating on the surface of the ADS NPs that could be easily modified via fluorination (ADSF NPs). The surface of fluorinated ADS NPs was further modified with a phospholipid layer to reduce aggregation and improve biocompatibility (ADSFL NPs). The contact angle and mean size of ADSFL NPs were 30.2 ± 4.4° and 353.1 ± 54.2 nm, respectively. The superhydrophobic layer generated interfacial nanobubbles on the outer shell of the NPs that reduced water-induced leakage of doxorubicin (DOX) sevenfold compared with the uncoated group and induced a cavitation effect upon ultrasound (US) sonication. Moreover, release of DOX from the ADSFL NPs could be triggered by US, and this release was further improved 1.6-fold in acidic aqueous conditions, indicating that the ADSFL NPs retained pH responsiveness. Enhanced sonography contrast and histological examination demonstrated that US could trigger cavitation activities from ADSFL NPs in vivo to induce vessel disruption and enhance the fluorescence intensity of DOX within the tumor region threefold under US imaging guidance compared with the ADSFL NPs-only group.

Combretastatin A4-loaded Poly (Lactic-co-glycolic Acid)/Soybean Lecithin Nanoparticles with Enhanced Drug Dissolution Rate and Antiproliferation Activity

OBJECTIVE

This study aimed to prepare combretastatin A4 (CA4)-loaded nanoparticles (CA4 NPs) using poly(lactic-co-glycolic acid) (PLGA) and soybean lecithin (Lipoid S100) as carriers, and further evaluate the physicochemical properties and cytotoxicities of CA4 NPs against cancer cells.

METHODS

CA4 NPs were prepared using a solvent evaporation technique. The effects of formulations on CA4 NPs were investigated in terms of particle size, zeta potential, encapsulation efficacy, and drug loading. The physicochemical properties of CA4 NPs were characterized using transmission electron microscopy, X-ray powder diffraction, differential scanning calorimetry, and Fourier transform infrared spectra. The drug release from CA4NPs was performed using a dialysis method. In addition, the cytotoxicity of CA4NPs against human alveolar basal epithelial (A549) cells was also evaluated.

RESULTS

CA4 NPs prepared with a low organic/water phase ratio (1:20) and high drug/PLGA mass ratio (1:2.5) exhibited a uniform hydrodynamic particle size of 142 nm, the zeta potential of -1.66 mV, and encapsulation efficacy and drug loading of 92.1% and 28.3%, respectively. CA4 NPs showed a significantly higher release rate than pure CA4 in pH 7.4 phosphate-buffered solution with 0.5% Tween 80. It was found that the drug molecules could change from the crystal state to an amorphous form when loaded into the PLGA/Lipoid S100 matrix, and some molecular interactions could also occur between the drug and PLGA. Importantly, CA4 NPs showed a remarkably higher antiproliferation activity against A549 cancer cells compared to pure CA4.

CONCLUSION

These results suggested the promising potential of PLGA/Lipoid S100 nanoparticles as the drug delivery system of CA4 for effective cancer therapy.