Bevacizumab-Induced Tumor Vasculature Normalization and Sequential Chemotherapy in Colorectal Cancer: An Interesting and Still Open Question

An ultrasound-activated nanoplatform remodels tumor microenvironment through diverse cell death induction for improved immunotherapy

Although nanomaterial-based nanomedicine provides many powerful tools to treat cancer, most focus on the "immunosilent" apoptosis process. In contrast, ferroptosis and immunogenic cell death, two non-apoptotic forms of programmed cell death (PCD), have been shown to enhance or alter the activity of the immune system. Therefore, there is a need to design and develop nanoplatforms that can induce multiple modes of cell death other than apoptosis to stimulate antitumor immunity and remodel the immunosuppressive tumor microenvironment for cancer therapy. In this study, a new type of multifunctional nanocomposite mainly consisting of HMME, Fe3+ and Tannic acid, denoted HFT NPs, was designed and synthesized to induce multiple modes of cell death and prime the tumor microenvironment (TME). The HFT NPs consolidate two functions into one nano-system: HMME as a sonosensitizer for the generation of reactive oxygen species (ROS) 1O2 upon ultrasound irradiation, and Fe3+ as a GSH scavenger for the induction of ferroptosis and the production of ROS ·OH through inorganic catalytic reactions. The administration of HFT NPs and subsequent ultrasound treatment caused cell death through the consumption of GSH, the generation of ROS, ultimately inducing apoptosis, ferroptosis, and immunogenic cell death (ICD). More importantly, the combination of HFT NPs and ultrasound irradiation could reshape the TME and recruit more T cell infiltration, and its combination with immune checkpoint blockade anti-PD-1 antibody could eradicate tumors with low immunogenicity and a cold TME. This new nano-system integrates sonodynamic and chemodynamic properties to achieve outstanding therapeutic outcomes when combined with immunotherapy. Collectively, this study demonstrates that it is possible to potentiate cancer immunotherapy through the rational and innovative design of relatively simple materials.

The Potential Influence of Residual or Recurrent Disease on Bevacizumab Treatment Efficacy in Ovarian Cancer: Current Evidence and Future Perspectives

There were high hopes for the new antiangiogenic medicament, bevacizumab, which could inhibit the creation of new blood vessels through binding to isoform A of vascular endothelial growth factor (VEGF). However, it is not only blood vessels that are responsible for tumor cell spread. During the process of tumor growth, lymphangiogenesis is mediated by other members of the VEGF family, specifically VEGF-C and VEGF-D, which act independent to bevacizumab. Therefore, based on the mechanism of bevacizumab action and the processes of angio- and lymphangiogenesis, we formed three hypotheses: (1) if the lymph nodes in primary ovarian cancers are metastatic, the outcome of bevacizumab treatment is worsened; (2) concerning the second-line treatment, bevacizumab will act in a weakened manner if recurrence occurs in lymph nodes as opposed to a local recurrence; (3) patients treated by bevacizumab are more likely to have recurrences in lymph nodes. These hypotheses raise the issue of the existing knowledge gap, which concerns the effect of bevacizumab on metastatic lymph nodes.

Selective Enhancing Blood Flow in Solid Tumor Tissue Is the Key for Achieving Satisfactory Delivery and Therapeutic Outcome of Nanodrugs via the EPR Effect

The enhanced permeability and retention effect (EPR effect) is a crucial phenomenon for understanding the pathophysiological characteristics of blood vasculature and microenvironments in solid tumors. It is also an essential concept for designing anticancer drugs that can be selectively delivered into tumor tissue via the unique extravasation and retention mechanism for macromolecular drugs. As tumor vasculature is highly heterogeneous, the intensities of the EPR effect vary according to the types and locations of solid tumors in different species. However, the EPR effect is universally observed in a broad spectrum of solid tumors in human cancer as well as experimental animal tumor models. The matter is how to utilize the EPR effect for drug design and clinical application. Many hypotheses were proposed and tested to enhance the EPR effect in solid tumors in order to increase the efficacy of drug delivery. However, we should focus on increasing the blood flow in tumors so that more drugs can be perfused and accumulated inside tumor tissue and execute anticancer activities. Angiotensin II co-administration and the approach of intratumor arterial infusion should be considered to achieve selective tumor tissue perfusion for nanodrugs.