Construction and antitumor effects of antitumor micelles with cyclic RGD-modified anlotinib

Developing targeted therapeutics for hepatocellular carcinoma: a critical assessment of promising phase II agents

INTRODUCTION

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the first for primary liver tumors. In recent years greater therapeutic advancement was represented by employment of tyrosine kinase inhibitors (TKIs) either in monotherapy or in combination with immune checkpoint inhibitors (ICIs).

AREAS COVERED

Major attention was given to target therapies in the last couple of years, especially in those currently under phase II trials. Priority was given either to combinations of novel ICI and TKIs or those targeting alternative mutations of major carcinogenic pathways.

EXPERT OPINION

As TKIs are playing a more crucial role in HCC therapeutic strategies, it is fundamental to further expand molecular testing and monitoring of acquired resistances. Despite the recent advancement in both laboratory and clinical studies, further research is necessary to face the discrepancy in clinical practice.

Indole Antitumor Agents in Nanotechnology Formulations: An Overview

The indole heterocycle represents one of the most important scaffolds in medicinal chemistry and is shared among a number of drugs clinically used in different therapeutic areas. Due to its varied biological activities, high unique chemical properties and significant pharmacological behaviors, indole derivatives have drawn considerable interest in the last decade as antitumor agents active against different types of cancers. The research of novel antiproliferative drugs endowed with enhanced efficacy and reduced toxicity led to the approval by U.S. Food and Drug Administration of the indole-based anticancer agents Sunitinib, Nintedanib, Osimertinib, Panobinostat, Alectinib and Anlotinib. Additionally, new drug delivery systems have been developed to protect the active principle from degradation and to direct the drug to the specific site for clinical use, thus reducing its toxicity. In the present work is an updated review of the recently approved indole-based anti-cancer agents and the nanotechnology systems developed for their delivery.

Multi-target tyrosine kinase inhibitor nanoparticle delivery systems for cancer therapy

Multi-target Tyrosine Kinase Inhibitors (MTKIs) have drawn substantial attention in tumor therapy. MTKIs could inhibit tumor cell proliferation and induce apoptosis by blocking the activity of tyrosine kinase. However, the toxicity and drug resistance of MTKIs severely restrict their further clinical application. The nano pharmaceutical technology based on MTKIs has attracted ever-increasing attention in recent years. Researchers deliver MTKIs through various types of nanocarriers to overcome drug resistance and improve considerably therapeutic efficiency. This review intends to summarize comprehensive applications of MTKIs nanoparticles in malignant tumor treatment. Firstly, the mechanism and toxicity were introduced. Secondly, various nanocarriers for MTKIs delivery were outlined. Thirdly, the combination treatment schemes and drug resistance reversal strategies were emphasized to improve the outcomes of cancer therapy. Finally, conclusions and perspectives were summarized to guide future research.

A nano-preparation approach to enable the delivery of daphnoretin to potentiate the therapeutical efficacy in hepatocellular cancer

Daphnoretin (DAP), isolated from a traditional Chinese medicine Wikstroemia indica (Linn. C. A. Meyer), could induce apoptosis of hepatocellular cancer (HCC) and inhibit tumor growth. However, the application of DAP in cancer therapies was hampered because to its poor solubility. Herein, this study aimed to design an approach of double-targeted nano-preparation to enable the delivery of DAP to potentiate the therapeutical efficacy in liver cancer via glycyrrhetinic acid-polyethylene glycol-block-poly (D,L-lactic acid)/polyethylene glycol-block-poly (D,L-lactic acid)-DAP (GPP/PP-DAP). In particular, the purity of separated DAP was up to 98.12% for preparation research. GPP/PP-DAP was successfully prepared by the thin-film hydration method. Subsequently, the GPP/PP-DAP was optimized by univariate analysis and the response surface methodology, producing a stable and systemically injectable nano-preparation. Impressively, on the one hand, cytotoxicity studies showed that the IC₅₀ of the GPP/PP-DAP was lower than that of free DAP. On the other hand, the GPP/PP-DAP was more likely to be endocytosed by HepG2 cells and targeted to the liver with orthotopic tumors, potentiating the therapeutical efficacy in HCC. Collectively, both in vitro and in vivo results indicated the excellent tumor inhibition and liver targeting of GPP/PP-DAP, suggesting the nano-preparation could serve as a potential drug delivery system for natural ingredients with anti-hepatoma activity to lay the theoretical foundation for clinical application.

Nano-drug delivery system with enhanced tumour penetration and layered anti-tumour efficacy

The low delivery efficiency of nano-drugs and limited tumour penetration are still huge challenges in treating solid tumours. Herein, we developed a pH-responsive nano-drug delivery system, CALS/PDMA@DOX, with a size conversion-layered delivery function. The system is composed of a pH-responsive cationic liposome loaded with DOX (CALS) and a polyamidoamine dendrimer loaded with DOX (PAMAM@DOX) modified with 2,3-dimethylmaleic anhydride (PDMA@DOX) using electrostatic adsorption. In the tumour microenvironment, the positively-charged large-size CALS and the positively-charged small-size PAMAM@DOX were dissociated to exert anti-tumour effects. CALS preferentially targeted tumour angiogenesis endothelial cells. Because of its small size and positive charge, PAMAM@DOX showed excellent tumour penetration. Significant tumour suppression by the system in vivo was confirmed in a 4T1 tumour xenograft mouse model. This pH-triggered size-switching layered delivery nanosystem is a safe and effective cancer treatment delivery platform that improves drug permeability and therapeutic efficacy.

SAR131675, a VEGRF3 Inhibitor, Modulates the Immune Response and Reduces the Growth of Colorectal Cancer Liver Metastasis

Simple Summary

Colorectal cancer most often metastasizes to the liver, and in most cases, it is unresectable at diagnosis. New treatment options targeting specific cancer characteristics are needed and are currently being explored. Herein we looked at the use of a selective VEGFR-3 tyrosine kinase inhibitor, SAR131675, as an anti-tumor agent in a mouse model of colorectal liver metastasis. We found that SAR131675 dramatically reduced tumor growth and changed the immune response within the tumor and the surrounding liver, suggesting the use of SAR131675 as an adjuvant therapy for colorectal liver metastasis.

Abstract

Most patients with colorectal cancer (CRC) develop metastases, predominantly in the liver (CLM). Targeted therapies are being investigated to improve current CLM treatments. This study tested the effectiveness of SAR131675, a selective VEGFR-3 tyrosine kinase inhibitor, to inhibit CLM in a murine model. Following intrasplenic induction of CLM, mice were treated daily with SAR131675. Tumor growth and immune infiltrates into tumor and liver tissues were assessed at 10-, 16- and 22-days post tumor induction by stereology, IHC and flow cytometry. SAR151675 treatment significantly reduced tumor burden and F4/80⁺ macrophages in the liver tissues. Analysis of immune cell infiltrates in liver showed tissue that at day 22, had the proportion of CD45⁺ leukocytes significantly reduced, particularly myeloid cells. Analysis of myeloid cells (CD11b⁺ CD45⁺) indicated that the proportion of F4/80⁻ Ly6C^low was significantly reduced, including a predominate PD-L1⁺ subset, while CD3⁺ T cells increased, particularly CD8⁺ PD1⁺, reflected by an increase in the CD8⁺:CD4⁺ T cell ratio. In the tumor tissue SAR11675 treatment reduced the predominant population of F4/80⁺ Ly6C^lo and increased CD4⁺ T cells. These results suggest that SAR131675 alters the immune composition within tumor and the surrounding liver in the later stages of development, resulting in a less immunosuppressive environment. This immunomodulation effect may contribute to the suppression of tumor growth.

Combining Fruquintinib and Doxorubicin in Size-Converted Nano-Drug Carriers for Tumor Therapy

Single-modality tumor therapy confronts many challenges, such as incomplete tumor ablation, tumor metastasis, and limited tumor tissue penetration. Combination therapy simultaneously achieves deep drug delivery to fully exert synergistic effects and has received increasing attention. Herein, based on the excellent efficacy of anti-angiogenesis therapy combined with chemotherapy and the specific size of the poly-amidoamine dendrimer (PAMAM), we developed a pH-triggered size-converted nano-drug delivery system to co-deliver fruquintinib (FRU) and doxorubicin (DOX). This study used cyclic Arg-Gly-Asp (cRGD) as the target, pH-responsive liposomes (PRLs), and PAMAM as the drug carrier. The FRU and DOX-loaded small-particle-size complex polyamide-amine-doxorubicin (PD) was encapsulated into PRLs with the target to construct a size-converted nano-drug delivery system, PRL-PD/FRU-cRGD. This nanoparticle (∼120 nm) actively targeted tumor tissues and used the acidic microenvironment outside tumor cells to release FRU and small-particle-size complex PD (∼15 nm), enabling the conversion of large-size nanoparticles to small-size nanoparticles and resulting in efficient tumor accumulation. In addition, the released PD could realize the deep delivery of DOX, showing efficient deep tumor penetration and further enhancing the tumor-suppressing effect. The results of in vivo and in vitro experiments showed that PRL-PD/FRU-cRGD exhibited the excellent synergistic effects of anti-angiogenesis therapy combined with chemotherapy and effectively inhibited tumor cell proliferation and metastasis, thereby achieving efficient tumor therapy. Thus, PRL-PD/FRU-cRGD shows great potential for combined tumor therapy.

Improving Outcomes of Tyrosine Kinase Inhibitors in Hepatocellular Carcinoma: New Data and Ongoing Trials

Targeted therapies such as oral tyrosine kinase inhibitors (TKIs) are the main therapeutic strategy effective for advanced hepatocellular carcinoma (HCC). Currently six tyrosine kinase inhibitors for HCC therapy have been approved. The newly approved first-line drug donafenib represent the major milestones in HCC therapeutics in recent years. However, drug resistance in HCC remains challenging due to random mutations in target receptors as well as downstream pathways. TKIs-based combinatorial therapies with immune checkpoint inhibitors such as PD-1/PD-L1 antibodies afford a promising strategy to further clinical application. Recent developments of nanoparticle-based TKI delivery techniques improve drug absorption and bioavailability, enhance efficient targeting delivery, prolonged circulation time, and reduce harmful side effects on normal tissues, which may improve the therapeutic efficacy of the TKIs. In this review, we summarize the milestones and recent progress in clinical trials of TKIs for HCC therapy. We also provide an overview of the novel nanoparticle-based TKI delivery techniques that enable efficient therapy.

Forward Precision Medicine: Micelles for Active Targeting Driven by Peptides

Precision medicine is based on innovative administration methods of active principles. Drug delivery on tissue of interest allows improving the therapeutic index and reducing the side effects. Active targeting by means of drug-encapsulated micelles decorated with targeting bioactive moieties represents a new frontier. Between the bioactive moieties, peptides, for their versatility, easy synthesis and immunogenicity, can be selected to direct a drug toward a considerable number of molecular targets overexpressed on both cancer vasculature and cancer cells. Moreover, short peptide sequences can facilitate cellular intake. This review focuses on micelles achieved by self-assembling or mixing peptide-grafted surfactants or peptide-decorated amphiphilic copolymers. Nanovectors loaded with hydrophobic or hydrophilic cytotoxic drugs or with gene silence sequences and externally functionalized with natural or synthetic peptides are described based on their formulation and in vitro and in vivo behaviors.

Tumor-Acidity Responsive Polymeric Nanoparticles for Targeting Delivery of Angiogenesis Inhibitor for Enhanced Antitumor Efficacy With Decreased Toxicity

Various nanocarriers with tumor targeting ability and improved pharmacokinetic property have been extensively utilized to reduce the toxicity of existing clinical chemotherapeutics. Herein, we showed that by encapsulating angiogenesis inhibitor anlotinib into polymeric nanoparticles, we could significantly decrease its in vivo toxicity. The introduction of pH-responsiveness into the nanocarrier further enhanced its anti-tumor activity. Systemic administration of the anlotinib-loaded nanocarrier into mice bearing A549 and 4T1 subcutaneous tumor received a higher tumor growth suppression and metastasis inhibition without detectable side effects. This strategy offers a promising option to improve the patient compliance of anlotinib.