Inducing vascular normalization: A promising strategy for immunotherapy

CAR-T cell therapy for patients with extramedullary multiple myeloma：Opportunities and challenges

Multiple myeloma (MM) is a hematological malignancy characterized by abnormal proliferation of clonal plasma cells, which is usually confined to the bone marrow (BM). But some malignant plasma cells grow independently of the BM, called extramedullary disease (EMD). With the clinical application of proteasome inhibitors, immunomodulators, monoclonal antibodies, and hematopoietic stem cell transplantation, the overall survival of MM patients has been significantly improved, but the survival of patients with EMD is still worse than that of non-EMD patients. There are currently no specific treatment options for EMD. chimeric antigen receptor T (CAR-T) cell therapy has brought a new era of immunotherapy. The application of CAR-T has significantly benefited many MM patients, and CAR-T may be a new hope for patients with EMD in the future. This review retrospectively summarizes the mechanism and prognosis of EMD, focusing on the application and potential of CAR-T in the treatment of EMD. It is hoped that this review can provide ideas for the treatment of EMD with CAR-T in the future.

Normalization of tumor vasculature by imiquimod: proposal for a new anticancer therapeutic indication for a TLR7 agonist

Imiquimod (IMQ), a drug from aminoquinoline group, is the toll-like receptor 7 (TLR7) agonist. It acts as an immunostimulant and radio-sensitizing agent. IMQ stimulates both innate and adaptive immune response. Despite studies conducted, there are no unambiguous data showing how IMQ affects the condition of tumor blood vessels. Tumor vasculature plays the main role in tumor progression. Formation of abnormal blood vessels increases area of hypoxia which recruits suppressor cells, blocks tumor infiltration by CD8+ T lymphocytes, inhibits efficacy of chemoterapeutic drug and leads to cancer relapse. Normalization is a type of therapy targeted at abnormal tumor blood vessels. Here, we demonstrated that 50 µg of IMQ inhibits the growth of melanoma tumors more efficiently, compared to other tested doses and the control group. Dose escalation did not improve the therapeutic antitumor potential of TLR7 agonist. A dose of 50 µg of IMQ most effectively reduced tumor blood vessel density. Imiquimod normalized tumor vasculature both structurally (by reducing vessel tortuosity and increasing pericyte coverage) and functionally (by improving tumor perfusion) in a dose-dependent manner. Hypoxia regions in tumors of treated mice were significantly reduced after IMQ administration. A dose of 50 µg of IMQ had also the greatest impact on the changes in tumor-infiltrating T lymphocytes levels. TLR7 agonist inhibited angiogenesis in treated mice. Functional vascular normalization by IMQ increases the effectiveness of low dose of doxorubicin. Higher dose of IMQ showed worse effects than lower doses including decreased tumor perfusion, increased tumor hypoxia and immunosuppression. This knowledge may help to optimize the combination of the selected IMQ dose with e.g. chemotherapy or radiotherapy to elicit synergistic effect in cancer treatment. To conclude, we outline IMQ repurposing as a vascular normalizing agent. Our research results may contribute to expanding the therapeutic indications for the use of IMQ in anticancer therapy in the future.

Targeting breast tumor extracellular matrix and stroma utilizing nanoparticles

Breast cancer is a complicated malignancy and is known as the most common cancer in women. Considerable experiments have been devoted to explore the basic impacts of the tumor stroma, particularly the extracellular matrix (ECM) and stromal components, on tumor growth and resistance to treatment. ECM is made up of an intricate system of proteins, glycosaminoglycans, and proteoglycans, and maintains structural support and controls key signaling pathways involved in breast tumors. ECM can block different drugs such as chemotherapy and immunotherapy drugs from entering the tumor stroma. Furthermore, the stromal elements, such as cancer-associated fibroblasts (CAFs), immune cells, and blood vessels, have crucial impacts on tumor development and therapeutic resistance. Recently, promising outcomes have been achieved in using nanotechnology for delivering drugs to tumor stroma and crossing ECM in breast malignancies. Nanoparticles have various benefits for targeting the breast tumor stroma, such as improved permeability and retention, extended circulation time, and the ability to actively target the area. This review covers the latest developments in nanoparticle therapies that focus on breast tumor ECM and stroma. We will explore different approaches using nanoparticles to target the delivery of anticancer drugs like chemotherapy, small molecule drugs, various antitumor products, and other specific synthetic therapeutic agents to the breast tumor stroma. Furthermore, we will investigate the utilization of nanoparticles in altering the stromal elements, such as reprogramming CAFs and immune cells, and also remodeling ECM.

Galunisertib promotes bevacizumab-induced vascular normalization in nasopharyngeal carcinoma: Multi-parameter MRI evaluation

Tumor vascular normalization (TVN) is associated with antitumor therapeutic efficacy in nasopharyngeal carcinoma (NPC). However, the short time window of TVN is the biggest hindrance to its wide clinical application. We investigated whether targeting transforming growth factor beta can enhance the TVN effect of bevacizumab (BEV)-induced patient-derived xenograft (PDX) models of NPC. We constructed mouse subcutaneous PDX models of NPC and classified the mice into four drug-treatment groups, namely placebo control, galunisertib, BEV, and galunisertib + BEV. We performed MRI multi-parameter examinations at different time points and evaluated the vascular density, vascular structure, and tumor hypoxia microenvironment by histopathology. The efficacy of chemotherapy and drug delivery was evaluated by administering cisplatin. We found that combined therapy with galunisertib and BEV significantly delayed tumor growth, enhanced the TVN effect, and improved chemotherapeutic efficacy compared with monotherapy. Mechanistically, galunisertib reversed the epithelial-mesenchymal transition process and inhibited the expression of hypoxia-inducible factor 1α and vascular endothelial growth factor by downregulating LAMC2. Correlation analysis of MRI data and pathological indicators showed that there was a good correlation between them.

Cancer Immunotherapy with "Vascular-Immune" Crosstalk as Entry Point: Associated Mechanisms, Therapeutic Drugs and Nano-Delivery Systems

Tumor vessels characterized by abnormal functions and structures hinder the infiltration and immune antigen presentation of immune cells by inducing the formation of an immunosuppressive microenvironment ("cold" environment). Vascular-targeted therapy has been proven to enhance immune stimulation and the effectiveness of immunotherapy by modulating the "cold" microenvironment, such as hypoxia and an acidic microenvironment. Notably, a therapeutic strategy based on "vascular-immune" crosstalk can achieve dual regulation of tumor vessels and the immune system by reprogramming the tumor microenvironment (TME), thus forming a positive feedback loop between tumor vessels and the immune microenvironment. From this perspective, we discuss the factors of tumor angiogenesis and "cold" TME formation. Building on this foundation, some vascular-targeted therapeutic drugs will be elaborated upon in detail to achieve dual regulation of tumor vessels and immunity. More importantly, we focus on cutting-edge nanotechnology in view of "vascular-immune" crosstalk and discuss the rational fabrication of tailor-made nanosystems for efficiently enhancing immunotherapy.

A mechanistic insight into the anticancer potentials of resveratrol: Current perspectives

Resveratrol is a widely recognized polyphenolic phytochemical found in various plants and their fruits, such as peanuts, grapes, and berry fruits. It is renowned for its several health advantages. The phytochemical is well known for its anticancer properties, and a substantial amount of clinical evidence has also established its promise as a chemotherapeutic agent. This study focuses on assessing the anticancer properties of resveratrol and gaining insight into the underlying molecular mechanisms. It also evaluates the biopharmaceutical, toxicological characteristics, and clinical utilization of resveratrol to determine its suitability for further development as a reliable anticancer agent. Therefore, the information about preclinical and clinical studies was collected from different electronic databases up-to-date (2018-2023). Findings from this study revealed that resveratrol has potent therapeutic benefits against various cancers involving different molecular mechanisms, such as induction of oxidative stress, cytotoxicity, inhibition of cell migration and invasion, autophagy, arresting of the S phase of the cell cycle, apoptotic, anti-angiogenic, and antiproliferative effects by regulating different molecular pathways including PI3K/AKT, p38/MAPK/ERK, NGFR-AMPK-mTOR, and so on. However, the compound has poor oral bioavailability due to reduced absorption; this limitation is overcome by applying nanotechnology (nanoformulation of resveratrol). Clinical application also showed therapeutic benefits in several types of cancer with no serious adverse effects. We suggest additional extensive studies to further check the efficacy, safety, and long-term hazards. This could involve a larger number of clinical samples to establish the compound as a reliable drug in the treatment of cancer.

Artemisinin suppressed tumour growth and induced vascular normalisation in oral squamous cell carcinoma via inhibition of macrophage migration inhibitory factor

BACKGROUND

Tumour vascular normalisation therapy advocates a balance between pro-angiogenic factors and anti-angiogenic factors in tumours. Artemisinin (ART), which is derived from traditional Chinese medicine, has been shown to inhibit tumour growth; however, the relationship between ART and tumour vascular normalisation in oral squamous cell carcinoma (OSCC) has not been previously reported.

METHODS

Different concentrations(0 mg/kg, 25 mg/kg, 50 mg/kg, 100 mg/kg)of ART were used to treat the xenograft nude mice model of OSCC. The effects of ART on migration and proliferation of OSCC and human umbilical vein endothelial cells (HUVEC) cells were detected by scratch assay and CCK-8 assay. OSCC cells with macrophage migration inhibitory factor (MIF) silenced were constructed to explore the effect of MIF.

RESULTS

Treatment with ART inhibited the growth and angiogenesis of OSCC xenografts in nude mice and downregulated vascular endothelial growth factor (VEGF), IL-8, and MIF expression levels. ART reduced the proliferation, migration, and tube formation of HUVEC, as well as the expression of VEGFR1 and VEGFR2. When the dose of ART was 50 mg/kg, vascular normalisation of OSCC xenografts was induced. Moreover, VEGF and IL-8 were needed in rhMIF restoring tumour growth and inhibit vascular normalisation after the addition of rhMIF to ART-treated cells.

CONCLUSION

Artemisinin might induce vascular normalisation and inhibit tumour growth in OSCC through the MIF-signalling pathway.

[Preliminary Study on Microvasculature Normalization Induced by Peritumoral Electroacupuncture in Mice With Breast Cancer Xenografts]

Objective

To observe the effect of peritumoral electroacupuncture on the induction of vascular normalization in a mouse breast cancer model.

Methods

A subcutaneous graft model of breast cancer was established with 4T1 breast cancer cell line in female BALB/c mice aged 6-8 weeks. The mice were randomly assigned to three groups, a tumor-bearing group (TG), peritumoral electroacupuncture tumor-bearing group (EATG), and bevacizumab tumor-bearing group (BTG), with 18 mice in each group. The TG mice did not receive any intervention, the EATG mice received peritumoral electroacupuncture for 30 minutes, and the BTG mice were intraperitoneally injected with bevacizumab at 10mg/kg. Immunofluorescence was performed to assess the expression of CD31/alpha smooth muscle actin (α-SMA) and hypoxia-inducible factor 1-alpha (HIF-1α) in the tumor tissue at various points of time, including before intervention and 3 days and 5 days after intervention. Then, 3 days after intervention, observation of morphological changes of the microvessels in the tumor tissue was performed through Hematoxylin and Eosin (HE) staining and scanning electron microscope.

Results

There was no significant difference in the expression of CD31, α-SMA, and HIF-1α in the tumor tissues of all groups before experimental intervention ( P>0.05). On day 3 of the experimental interventions, the CD31 and HIF-1α expression levels in the tumor tissues of the EATG and BTG mice were significantly reduced ( P<0.01), while α-SMA expression levels were significantly increased ( P<0.01) in both groups. On day 5 of the experimental interventions, the CD31 and HIF-1α expression levels in the tumor tissues of the EATG and BTG mice were still significantly lower than those in the TG mice ( P<0.01), while the α-SMA expression level was significantly higher than that in the TG group ( P<0.05). On day 3 of the experimental interventions, H&E staining showed visible microvessels in the tumor tissues of all 3 groups. In addition, scanning electron microscopic observation showed that the tumor microvessel walls of the TG mice were rough and defective, and that obvious deformities appeared in the lumen. In contrast, the walls of the microvessels of the EATG and BTG mice were generally intact and there was no obvious deformities in the lumen.

Conclusion

Peritumoral electroacupuncture may induce microvasculature normalization by decreasing microvascular density and increasing pericyte coverage of the neovasculature, thereby improving hypoxic microenvironment of breast cancer in mice.

Angiogenic signaling pathways and anti-angiogenic therapy for cancer

Angiogenesis, the formation of new blood vessels, is a complex and dynamic process regulated by various pro- and anti-angiogenic molecules, which plays a crucial role in tumor growth, invasion, and metastasis. With the advances in molecular and cellular biology, various biomolecules such as growth factors, chemokines, and adhesion factors involved in tumor angiogenesis has gradually been elucidated. Targeted therapeutic research based on these molecules has driven anti-angiogenic treatment to become a promising strategy in anti-tumor therapy. The most widely used anti-angiogenic agents include monoclonal antibodies and tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factor (VEGF) pathway. However, the clinical benefit of this modality has still been limited due to several defects such as adverse events, acquired drug resistance, tumor recurrence, and lack of validated biomarkers, which impel further research on mechanisms of tumor angiogenesis, the development of multiple drugs and the combination therapy to figure out how to improve the therapeutic efficacy. Here, we broadly summarize various signaling pathways in tumor angiogenesis and discuss the development and current challenges of anti-angiogenic therapy. We also propose several new promising approaches to improve anti-angiogenic efficacy and provide a perspective for the development and research of anti-angiogenic therapy.