Acidic tumor microenvironment-sensitive liposomes enhance colorectal cancer therapy by acting on both tumor cells and cancer-associated fibroblasts

Advancements in 3D In Vitro Models for Colorectal Cancer

The process of drug discovery and pre-clinical testing is currently inefficient, expensive, and time-consuming. Most importantly, the success rate is unsatisfactory, as only a small percentage of tested drugs are made available to oncological patients. This is largely due to the lack of reliable models that accurately predict drug efficacy and safety. Even animal models often fail to replicate human-specific pathologies and human body's complexity. These factors, along with ethical concerns regarding animal use, urge the development of suitable human-relevant, translational in vitro models.

Antitumor efficacy and potential mechanism of FAP-targeted radioligand therapy combined with immune checkpoint blockade

Radiotherapy combined with immune checkpoint blockade holds great promise for synergistic antitumor efficacy. Targeted radionuclide therapy delivers radiation directly to tumor sites. LNC1004 is a fibroblast activation protein (FAP)-targeting radiopharmaceutical, conjugated with the albumin binder Evans Blue, which has demonstrated enhanced tumor uptake and retention in previous preclinical and clinical studies. Herein, we demonstrate that 68Ga/177Lu-labeled LNC1004 exhibits increased uptake and prolonged retention in MC38/NIH3T3-FAP and CT26/NIH3T3-FAP tumor xenografts. Radionuclide therapy with 177Lu-LNC1004 induced a transient upregulation of PD-L1 expression in tumor cells. The combination of 177Lu-LNC1004 and anti-PD-L1 immunotherapy led to complete eradication of all tumors in MC38/NIH3T3-FAP tumor-bearing mice, with mice showing 100% tumor rejection upon rechallenge. Immunohistochemistry, single-cell RNA sequencing (scRNA-seq), and TCR sequencing revealed that combination therapy reprogrammed the tumor microenvironment in mice to foster antitumor immunity by suppressing malignant progression and increasing cell-to-cell communication, CD8+ T-cell activation and expansion, M1 macrophage counts, antitumor activity of neutrophils, and T-cell receptor diversity. A preliminary clinical study demonstrated that 177Lu-LNC1004 was well-tolerated and effective in patients with refractory cancers. Further, scRNA-seq of peripheral blood mononuclear cells underscored the importance of addressing immune evasion through immune checkpoint blockade treatment. This was emphasized by the observed increase in antigen processing and presentation juxtaposed with T cell inactivation. In conclusion, our data supported the efficacy of immunotherapy combined with 177Lu-LNC1004 for cancer patients with FAP-positive tumors.

Innovations in Breaking Barriers: Liposomes as Near-Perfect Drug Carriers in Ischemic Stroke Therapy

Liposomes, noted for their tunable particle size, surface customization, and varied drug delivery capacities, are increasingly acknowledged in therapeutic applications. These vesicles exhibit surface flexibility, enabling the incorporation of targeting moieties or peptides to achieve specific targeting and avoid lysosomal entrapment. Internally, their adaptable architecture permits the inclusion of a broad spectrum of drugs, contingent on their solubility characteristics. This study thoroughly reviews liposome fabrication, surface modifications, and drug release mechanisms post-systemic administration, with a particular emphasis on drugs crossing the blood-brain barrier (BBB) to address lesions. Additionally, the review delves into recent developments in the use of liposomes in ischemic stroke models, offering a comparative evaluation with other nanocarriers like exosomes and nano-micelles, thereby facilitating their clinical advancement.

pH-sensitive liposomes bearing a chemotherapeutic agent and a natural apoptosis modulator for effective intracellular delivery to the solid tumor

The intracellular delivery of the drug to the solid tumor is a major challenge in the treatment of solid tumors. This project aims to increase cytosolic drug delivery using the endosomal escape of drugs. Topotecan (TPT) and capsaicin were used for the treatment of solid tumors. The pH-dependent conversion of active lactone form to inactive carboxylic form is a major problem of TPT that limits its therapeutic use. Liposomal encapsulation of TPT improved the stability of active lactone form and increased the therapeutic efficacy of TPT. Endosomal degradation of liposomes may reduce the content in the target cells. To solve these problems, pH-sensitive liposomes (pSLPs) were developed which improved the intracellular drug delivery by the endosomal escape of drugs. The liposomes (LPs) bearing the drug(s) were prepared using the cast film method and optimized for various formulation and process variables using the Design-Expert 7 software by employing the Box-Behnken design (BBD). The developed hyaluronic acid (HA)-conjugated pSLPs (HA-pSLPs) displayed a vesicle size of 166.5 ± 2.31 nm, zeta potential - 30.53 ± 0.91, and entrapment efficiency of 44.39 ± 1.78%, and 73.48 ± 2.15% for TPT and CAP, respectively. HA-pSLPs displayed better cytotoxicity in comparison to free drugs either single or in combination on the MCF-7 cell line. The apoptosis and cellular uptake of HA-pSLPs were increased ⁓ 4.45-fold and ⁓ 6.95-fold as compared to unconjugated pSLPs, respectively. The pharmacokinetic studies in Balb/c mice demonstrated that HA-pSLPs increased the half-life, MRT, and AUC in comparison to the free drug solution. The HA-pSLPs formulation has shown remarkable tumor regression as compared to PpSLPs, pSLPs, and free drug combinations. These results demonstrated that TPT- and CAP-loaded HA-pSLPs offer a potential platform for targeted drug delivery to solid tumors.

Relaxin-encapsulated polymeric metformin nanoparticles remodel tumor immune microenvironment by reducing CAFs for efficient triple-negative breast cancer immunotherapy

Cancer-associated fibroblasts (CAFs) are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment, leading to the failure of triple-negative breast cancer (TNBC) immunotherapy. Therefore, depleting CAFs may enhance the effect of immunotherapy (such as PD-L1 antibody). Relaxin (RLN) has been demonstrated to significantly improve transforming growth factor-β (TGF-β) induced CAFs activation and tumor immunosuppressive microenvironment. However, the short half-life and systemic vasodilation of RLN limit its in vivo efficacy. Here, plasmid encoding relaxin (pRLN) to locally express RLN was delivered with a new positively charged polymer named polymeric metformin (PolyMet), which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before. In order to improve the stability of pRLN in vivo, this complex was further formed lipid poly-γ-glutamic acid (PGA)/PolyMet-pRLN nanoparticle (LPPR). The particle size of LPPR was 205.5 ± 2.9 nm, and the zeta potential was +55.4 ± 1.6 mV. LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1^luc/CAFs tumor spheres in vitro. In vivo, it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment, which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration. Thus, LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse, and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody (aPD-L1). Altogether, this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.

A New Treatment Landscape for RCC: Association of the Human Microbiome with Improved Outcomes in RCC

Microbes play different roles in metabolism, local or systemic inflammation, and immunity, and the human microbiome in tumor microenvironment (TME) is important for modulating the response to immunotherapy in cancer patients. Renal cell carcinoma (RCC) is an immunogenic tumor, and immunotherapy is the backbone of its treatment. Correlations between the microbiome and responsiveness to immune checkpoint inhibitors have been reported. This review summarizes the recent therapeutic strategies for RCC and the effects of TME on the systemic therapy of RCC. The current understanding and advances in microbiome research and the relationship between the microbiome and the response to immunotherapy for RCC are also discussed. Improving our understanding of the role of the microbiome in RCC treatment will facilitate the development of microbiome targeting therapies to modify the tumor microbiome and improve treatment outcomes.

Research Progress on Nanoparticles-Based CRISPR/Cas9 System for Targeted Therapy of Tumors

Cancer is a genetic mutation disease that seriously endangers the health and life of all human beings. As one of the most amazing academic achievements in the past decade, CRISPR/Cas9 technology has been sought after by many researchers due to its powerful gene editing capability. CRISPR/Cas9 technology shows great potential in oncology, and has become one of the most promising technologies for cancer genome-editing therapeutics. However, its efficiency and the safety issues of in vivo gene editing severely limit its widespread application. Therefore, developing a suitable delivery method for the CRISPR/Cas9 system is an urgent problem to be solved at present. Rapid advances in nanomedicine suggest nanoparticles could be a viable option. In this review, we summarize the latest research on the potential use of nanoparticle-based CRISPR/Cas9 systems in cancer therapeutics, in order to further their clinical application. We hope that this review will provide a novel insight into the CRISPR/Cas9 system and offer guidance for nanocarrier designs that will enable its use in cancer clinical applications.

Normalization of the tumor microvasculature based on targeting and modulation of the tumor microenvironment

Angiogenesis is an essential process for tumor development. Owing to the imbalance between pro- and anti-angiogenic factors, the tumor vasculature possesses the characteristics of tortuous, hyperpermeable vessels and compressive force, resulting in a reduction in the effect of traditional chemotherapy and radiotherapy. Anti-angiogenesis has emerged as a promising strategy for cancer treatment. Tumor angiogenesis, however, has been proved to be a complex process in which the tumor microenvironment (TME) plays a vital role in the initiation and development of the tumor microvasculature. The host stromal cells in the TME, such as cancer associated fibroblasts (CAFs), tumor associated macrophages (TAMs) and Treg cells, contribute to angiogenesis. Furthermore, the abnormal metabolic environment, such as hypoxia and acidosis, leads to the up-regulated expression of angiogenic factors. Indeed, normalization of the tumor microvasculature via targeting and modulating the TME has become a promising strategy for anti-angiogenesis and anti-tumor therapy. In this review, we summarize the abnormalities of the tumor microvasculature, tumor angiogenesis induced by an abnormal metabolic environment and host stromal cells, as well as drug delivery therapies to restore the balance between pro- and anti-angiogenic factors by targeting and normalizing the tumor vasculature in the TME.