Tumor-Associated Fibroblast-Targeting Nanoparticles for Enhancing Solid Tumor Therapy: Progress and Challenges

Revealing tumor cells and tissues with high selectivity through folic acid-targeted nanofluorescence probes responsive to acidic microenvironments

Tumor-specific fluorescent probes must fulfill the dual requirements of targeted accumulation within tumors and high-resolution imaging capabilities. To achieve both tumor-targeted accumulation and high-resolution imaging performance, we developed a composite comprising an acid-responsive bodipy conjugated to amphiphilic PEG-b-PLA polymer, along with folic acid (FA)-modified PEG-b-PLA as a targeting moiety for active tumor-specific accumulation. Finally, a novel assembly of hybrid fluorescent nanoparticles was successfully synthesized by integrating these two components, demonstrating exceptional responsiveness to acidic conditions for fluorescence excitation and remarkable tumor-targeted accumulation capabilities. We conducted comprehensive in vitro and in vivo investigations employing techniques such as analysis of physicochemical properties, fluorescence-based probes detection at varying pH levels, assessment of in vitro cytotoxicity, evaluation of cellular uptake capacity, analysis of lysosomal co-localization imaging, examination of tumor fluorescence images in vivo, and investigation of biological distribution patterns. The results demonstrated that the acid-responsive nanofluorescence probe we designed and synthesized possesses desirable physical and chemical characteristics, including a small particle size and low cytotoxicity. Moreover, it exhibits rapid real-time response to acidic environments and displays enhanced fluorescence intensity, enabling the real-time tracking of probe entry into tumor cells as well as intracellular lysozyme accumulation. We achieved highly specific in vivo tumor visualization by combining nanoprobes targeting folate receptor. Through imaging cervical tumor mice, we demonstrated the precise imaging performance and high targeted accumulation of FA-targeted nanofluorescence probes in tumor tissue. Furthermore, we confirmed the in vivo safety of the FA-targeted nanofluorescence probe through biological distribution analysis. These findings highlight the potential widespread application of FA-targeted acid-responsive nanofluorescence probes for selective imaging of tumor cells and tissues.

Exploring the anti-inflammatory and anti-fibrotic activity of NFκB decoy oligodeoxynucleotide-loaded spermine-functionalized acetalated nanoparticles

Chronic inflammation, oxidative stress, and airway remodelling represent the principal pathophysiological features of chronic respiratory disorders. Inflammation stimuli like lipopolysaccharide (LPS) activate macrophages and dendritic cells, with concomitant M1 polarization and release of pro-inflammatory cytokines. Chronic inflammation and oxidative stress lead to airway remodelling causing irreversible functional and structural alterations of the lungs. Airway remodelling is multifactorial, however, the hormone transforming growth factor-β (TGF-β) is one of the main contributors to fibrotic changes. The signalling pathways mediating inflammation and remodelling rely both on the transcription factor nuclear factor-κB (NFκB), underlying the potential of NFκB inhibition as a therapeutic strategy for chronic respiratory disorders. In this study, we encapsulated an NFκB-inhibiting decoy oligodeoxynucleotide (ODN) in spermine-functionalized acetalated dextran (SpAcDex) nanoparticles and tested the in vitro anti-inflammatory and anti-remodelling activity of this formulation. We show that NF-κB ODN nanoparticles counteract inflammation by reversing LPS-induced expression of the activation marker CD40 in myeloid cells and counteracts remodelling features by reversing the TGF-β-induced expression of collagen I and α-smooth muscle actin in human dermal fibroblast. In summary, our study highlights the great potential of inhibiting NFκB via decoy ODN as a therapeutic strategy tackling multiple pathophysiological features underlying chronic respiratory conditions.

Membrane Fusion Liposomes Deliver Antifibrotic and Chemotherapeutic Drugs Sequentially to Enhance Tumor Treatment Efficacy by Reshaping Tumor Microenvironment

The intricate tumor microenvironment in triple-negative breast cancer (TNBC) hampers chemotherapy and immunotherapy efficacy due to dense extracellular matrix (ECM) by tumor-associated fibroblasts (TAFs). Nanoparticle-based therapies, especially "all-in-one" nanoparticles, have shown great potential in combined drug delivery strategies to reshape the tumor microenvironment and enhance therapeutic efficiency. However, these "all-in-one" nanoparticles suffer from limitations in targeting different target cells, uncontrollable dosing ratio, and disregarding the impact of delivery schedules. This study prepared cell membrane fusion liposomes (TAFsomes and CCMsomes) to load FDA-approved antifibrotic drug pirfenidone (PFD/TAFsomes) and antitumor drug doxorubicin (DOX/CCMsomes). These liposomes can specifically target TAFs cells and tumor cells, and combined administration can effectively inhibit TAFs activity, reshape the tumor microenvironment (TME), and significantly enhance the tumor chemotherapy efficacy. Combined drug delivery defeats "all-in-one" liposomes (DOX/PFD/Liposomes, DOX/PFD/TAFsomes, and DOX/PFD/CCMsomes) by flexibly adjusting the drug delivery ratio. Moreover, an asynchronous delivery strategy that optimizes the administration schedule not only further improves the therapeutic effect, but also amplifies the effectiveness of α-PD-L1 immunotherapy by modulating the tumor immune microenvironment. This delivery strategy provides a personalized treatment approach with clinical translation potential, providing new ideas for enhancing the therapeutic effect against solid tumors such as TNBC.

Engineered nanomicelles inhibit the tumour progression via abrogating the prostaglandin-mediated immunosuppression

Cancer treatment is challenged due to immunosuppressive inflammatory tumour microenvironment (TME) caused by infiltration of tumour-promoting and inhibition of tumour-inhibiting immune cells. Here, we report the engineering of chimeric nanomicelles (NMs) targeting the cell proliferation using docetaxel (DTX) and inflammation using dexamethasone (DEX) that alters the immunosuppressive TME. We show that a combination of phospholipid-DTX conjugate and PEGylated-lipid-DEX conjugate can self-assemble to form sub-100 nm chimeric NMs (DTX-DEX NMs). Anti-cancer activities against syngeneic and xenograft mouse models showed that the DTX-DEX NMs are more effective in tumour regression, enhance the survival of mice over other treatment modes, and alter the tumour stroma. DTX-DEX NMs cause a significant reduction in myeloid-derived suppressor cells, alter the polarization of macrophages, and enhance the accumulation of cytotoxic CD4+ and CD8+ T cells in tumour tissues, along with alterations in cytokine expression. We further demonstrated that these DTX-DEX NMs inhibit the synthesis of prostaglandins, especially PGE2, by targeting the cyclooxygenase 2 that is partly responsible for immunosuppressive TME. Therefore, this study presents, for the first time, the engineering of lithocholic acid-derived chimeric NMs that affect the prostaglandin pathway, alter the TME, and mitigate tumour progression with enhanced mice survival.

Theranostic applications of peptide-based nanoformulations for growth factor defective cancers

Growth factors play a pivotal role in orchestrating cellular growth and division by binding to specific cell surface receptors. Dysregulation of growth factor production or activity can contribute to the uncontrolled cell proliferation observed in cancer. Peptide-based nanoformulations (PNFs) have emerged as promising therapeutic strategies for growth factor-deficient cancers. PNFs offer multifaceted capabilities including targeted delivery, imaging modalities, combination therapies, resistance modulation, and personalized medicine approaches. Nevertheless, several challenges remain, including limited specificity, stability, pharmacokinetics, tissue penetration, toxicity, and immunogenicity. To address these challenges and optimize PNFs for clinical translation, in-depth investigations are warranted. Future research should focus on elucidating the intricate interplay between peptides and nanoparticles, developing robust spectroscopic and computational methodologies, and establishing a comprehensive understanding of the structure-activity relationship governing peptide-nanoparticle interactions. Bridging these knowledge gaps will propel the translation of peptide-nanoparticle therapies from bench to bedside. While a few peptide-nanoparticle drugs have obtained FDA approval for cancer treatment, the integration of nanostructured platforms with peptide-based medications holds tremendous potential to expedite the implementation of innovative anticancer interventions. Therefore, growth factor-deficient cancers present both challenges and opportunities for targeted therapeutic interventions, with peptide-based nanoformulations positioned as a promising avenue. Nonetheless, concerted research and development endeavors are essential to optimize the specificity, stability, and safety profiles of PNFs, thereby advancing the field of peptide-based nanotherapeutics in the realm of oncology research.

Targeted Cyclo[8]pyrrole-Based NIR-II Photoacoustic Tomography Probe for Suppression of Orthotopic Pancreatic Tumor Growth and Intra-abdominal Metastases

Pancreatic cancer is highly lethal. New diagnostic and treatment modalities are desperately needed. We report here that an expanded porphyrin, cyclo[8]pyrrole (CP), with a high extinction coefficient (89.16 L/g·cm) within the second near-infrared window (NIR-II), may be formulated with an αvβ3-specific targeting peptide, cyclic-Arg-Gly-Asp (cRGD), to form cRGD-CP nanoparticles (cRGD-CPNPs) with promising NIR-II photothermal (PT) therapeutic and photoacoustic (PA) imaging properties. Studies with a ring-array PA tomography system, coupled with analysis of control nanoparticles lacking a targeting element (CPNPs), revealed that cRGD conjugation promoted the delivery of the NPs through abnormal vessels around the tumor to the solid tumor core. This proved true in both subcutaneous and orthotopic pancreatic tumor mice models, as confirmed by immunofluorescent studies. In combination with NIR-II laser photoirradiation, the cRGD-CPNPs provided near-baseline tumor growth inhibition through PTT both in vitro and in vivo. Notably, the combination of the present cRGD-CPNPs and photoirradiation was found to inhibit intra-abdominal metastases in an orthotopic pancreatic tumor mouse model. The cRGD-CPNPs also displayed good biosafety profiles, as inferred from PA tomography, blood analyses, and H&E staining. They thus appear promising for use in combined PA imaging and PT therapeutic treatment of pancreatic cancer.

Improving the Efficacy of Common Cancer Treatments via Targeted Therapeutics towards the Tumour and Its Microenvironment

Cancer is defined as the uncontrolled proliferation of heterogeneous cell cultures in the body that develop abnormalities and mutations, leading to their resistance to many forms of treatment. Left untreated, these abnormal cell growths can lead to detrimental and even fatal complications for patients. Radiation therapy is involved in around 50% of cancer treatment workflows; however, it presents significant recurrence rates and normal tissue toxicity, given the inevitable deposition of the dose to the surrounding healthy tissue. Chemotherapy is another treatment modality with excessive normal tissue toxicity that significantly affects patients' quality of life. To improve the therapeutic efficacy of radiotherapy and chemotherapy, multiple conjunctive modalities have been proposed, which include the targeting of components of the tumour microenvironment inhibiting tumour spread and anti-therapeutic pathways, increasing the oxygen content within the tumour to revert the hypoxic nature of the malignancy, improving the local dose deposition with metal nanoparticles, and the restriction of the cell cycle within radiosensitive phases. The tumour microenvironment is largely responsible for inhibiting nanoparticle capture within the tumour itself and improving resistance to various forms of cancer therapy. In this review, we discuss the current literature surrounding the administration of molecular and nanoparticle therapeutics, their pharmacokinetics, and contrasting mechanisms of action. The review aims to demonstrate the advancements in the field of conjugated nanomaterials and radiotherapeutics targeting, inhibiting, or bypassing the tumour microenvironment to promote further research that can improve treatment outcomes and toxicity rates.

Global cluster analysis and network visualization in cancer-associated fibroblast: insights from Web of Science database from 1999 to 2021

BACKGROUND

A scientific and comprehensive analysis of the current status and trends in the field of cancer-associated fibroblast (CAF) research is worth investigating. This study aims to investigate and visualize the development, research frontiers, and future trends in CAFs both quantitatively and qualitatively based on a bibliometric approach.

METHODS

A total of 5518 publications were downloaded from the Science Citation Index Expanded of Web of Science Core Collection from 1999 to 2021 and identified for bibliometric analysis. Visualized approaches, OriginPro (version 9.8.0.200) and R (version 4.2.0) software tools were used to perform bibliometric and knowledge-map analysis.

RESULTS

The number of publications on CAFs increased each year, and the same tendency was observed in the RRI. Apart from China, the countries with the largest number of publications and the most cited frequency were mainly Western developed countries, especially the USA. Cancers was the journal with the largest number of articles published in CAFs, and Oncology was the most popular research orientation. The most productive author was Lisanti MP, and the University of Texas System was ranked first in the institutions. In addition, the topics of CAFs could be divided into five categories, including tumor classification, prognostic study, oncologic therapies, tumor metabolism and tumor microenvironment.

CONCLUSIONS

This is the first thoroughly scientific bibliometric analysis and visualized study of the global research field on CAFs over the past 20 years. The study may provide benefits for researchers to master CAFs' dynamic evolution and research trends.

Advancement in Biopolymer Assisted Cancer Theranostics

Applications of nanotechnology have increased the importance of research and nanocarriers, which have revolutionized the method of drug delivery to treat several diseases, including cancer, in the past few years. Cancer, one of the world's fatal diseases, has drawn scientists' attention for its multidrug resistance to various chemotherapeutic drugs. To minimize the side effects of chemotherapeutic agents on healthy cells and to develop technological advancement in drug delivery systems, scientists have developed an alternative approach to delivering chemotherapeutic drugs at the targeted site by integrating it inside the nanocarriers like synthetic polymers, nanotubes, micelles, dendrimers, magnetic nanoparticles, quantum dots (QDs), lipid nanoparticles, nano-biopolymeric substances, etc., which has shown promising results in both preclinical and clinical trials of cancer management. Besides that, nanocarriers, especially biopolymeric nanoparticles, have received much attention from researchers due to their cost-effectiveness, biodegradability, treatment efficacy, and ability to target drug delivery by crossing the blood-brain barrier. This review emphasizes the fabrication processes, the therapeutic and theragnostic applications, and the importance of different biopolymeric nanocarriers in targeting cancer both in vitro and in vivo, which conclude with the challenges and opportunities of future exploration using biopolymeric nanocarriers in onco-therapy with improved availability and reduced toxicity.

Caenorhabditis elegans as a Prediction Platform for Nanotechnology-Based Strategies: Insights on Analytical Challenges

Nanotechnology-based strategies have played a pivotal role in innovative products in different technological fields, including medicine, agriculture, and engineering. The redesign of the nanometric scale has improved drug targeting and delivery, diagnosis, water treatment, and analytical methods. Although efficiency brings benefits, toxicity in organisms and the environment is a concern, particularly in light of global climate change and plastic disposal in the environment. Therefore, to measure such effects, alternative models enable the assessment of impacts on both functional properties and toxicity. Caenorhabditis elegans is a nematode model that poses valuable advantages such as transparency, sensibility in responding to exogenous compounds, fast response to perturbations besides the possibility to replicate human disease through transgenics. Herein, we discuss the applications of C. elegans to nanomaterial safety and efficacy evaluations from one health perspective. We also highlight the directions for developing appropriate techniques to safely adopt magnetic and organic nanoparticles, and carbon nanosystems. A description was given of the specifics of targeting and treatment, especially for health purposes. Finally, we discuss C. elegans potential for studying the impacts caused by nanopesticides and nanoplastics as emerging contaminants, pointing out gaps in environmental studies related to toxicity, analytical methods, and future directions.

Resveratrol Loaded Liposomes Disrupt Cancer Associated Fibroblast Communications within the Tumor Microenvironment to Inhibit Colorectal Cancer Aggressiveness

Colorectal cancer (CRC) is a cancer-associated fibroblast, CAF-rich tumor. CAF promotes cancer cell proliferation, metastasis, drug resistance via secretes soluble factors, and extracellular matrices which leads to dense stroma, a major barrier for drug delivery. Resveratrol (RES) is a polyphenolic compound, has several pharmacologic functions including anti-inflammation and anticancer effects. Considering tumor microenvironment of CRC, resveratrol-loaded liposome (L-RES) was synthesized and employed to inhibit CAF functions. The L-RES was synthesized by thin-film hydration method. The cytotoxicity of L-RES was evaluated using MTT assay. Effect of L-RES treated CAF on tumor spheroid growth was performed. Cell invasion was determined using spheroid invasion assay. The effect of L-RES on 5-fluorouracil (5-FU) sensitivity of CRC cells was determined in co-cultured tumor spheroids. Subtoxic dose of L-RES was selected to study possible inhibiting CAF functions. Decreased CAF markers, α-SMA and IL-6 levels, were observed in L-RES treated activated fibroblast. Interestingly, the activated fibroblast promoted invasive ability and drug resistance of CRC cells in co-culture condition of both 2D and 3D cultures and was attenuated by L-RES treatment in the activated fibroblast. Therefore, L-RES provides a promising drug delivery strategy for CRC treatment by disrupting the crosstalk between CRC cells and CAF.

Phenethyl Isothiocyanate-Conjugated Chitosan Oligosaccharide Nanophotosensitizers for Photodynamic Treatment of Human Cancer Cells

The aim of this study is to synthesize phenethyl-conjugated chitosan oligosaccharide (COS) (abbreviated as ChitoPEITC) conjugates and then fabricate chlorin E6 (Ce6)-incorporated nanophotosensitizers for photodynamic therapy (PDT) of HCT-116 colon carcinoma cells. PEITC was conjugated with the amine group of COS. Ce6-incorporated nanophotosensitizers using ChitoPEITC (ChitoPEITC nanophotosensitizers) were fabricated by dialysis method. 1H nuclear magnetic resonance (NMR) spectra showed that specific peaks of COS and PEITC were observed at ChitoPEITC conjugates. Transmission electron microscope (TEM) confirmed that ChitoPEITC nanophotosensitizers have spherical shapes with small hydrodynamic diameters less than 200 nm. The higher PEITC contents in the ChitoPEITC copolymer resulted in a slower release rate of Ce6 from nanophotosensitizers. Furthermore, the higher Ce6 contents resulted in a slower release rate of Ce6. In cell culture study, ChitoPEITC nanophotosensitizers showed low toxicity against normal CCD986Sk human skin fibroblast cells and HCT-116 human colon carcinoma cells in the absence of light irradiation. ChitoPEITC nanophotosensitizers showed a significantly higher Ce6 uptake ratio than that of free Ce6. Under light irradiation, cellular reactive oxygen species (ROS) production of nanophotosensitizers was significantly higher than that of free Ce6. Especially, PEITC and/or ChitoPEITC themselves contributed to the production of cellular ROS regardless of light irradiation. ChitoPEITC nanophotosensitizers showed significantly higher PDT efficacy against HCT-116 cells than that of free Ce6. These results indicate that ChitoPEITC nanophotosensitizers have superior potential in Ce6 uptake, ROS production and PDT efficacy. In the HCT-116 cell-bearing mice tumor-xenograft model, ChitoPEITC nanophotosensitizers efficiently inhibited growth of tumor volume rather than free Ce6. In the animal imaging study, ChitoPEITC nanophotosensitizers were concentrated in the tumor tissue, i.e., fluorescence intensity in the tumor tissue was stronger than that of other tissues. We suggest that ChitoPEITC nanophotosensitizers are a promising candidate for the treatment of human colon cancer cells.

A CFH peptide-decorated liposomal oxymatrine inactivates cancer-associated fibroblasts of hepatocellular carcinoma through epithelial–mesenchymal transition reversion

Cancer-associated fibroblasts (CAFs) deteriorate tumor microenvironment (TME) and hinder intra-tumoral drug delivery. Direct depleting CAFs exists unpredictable risks of tumor metastasis. Epithelial–mesenchymal transition (EMT) is a critical process of CAFs converted from hepatic stellate cells during hepatocellular tumorigenesis; however, until now the feasibility of reversing EMT to battle hepatocellular carcinoma has not been comprehensively explored. In this study, we report a CFH peptide (CFHKHKSPALSPVGGG)-decorated liposomal oxymatrine (CFH/OM-L) with a high affinity to Tenascin-C for targeted inactivating CAFs through reversing EMT, which is verified by the upregulation of E-cadherin and downregulation of vimentin, N-cadherin, and snail protein in vivo and in vitro. After the combination with icaritin-loaded lipid complex, CFH/OM-L obviously boosts the comprehensive anticancer efficacy in both 3D tumor spheroids and stromal-rich tumor xenograft nude mouse models. The combinational therapy not only effectively reversed the in vivo EMT process but also significantly lowered the collagen, creating favorable conditions for deep penetration of nanoparticles. More importantly, CFH/OM-L does not kill but inactivates CAFs, resulting in not only a low risk of tumor metastasis but also a reprogramming TME, such as M1 tumor-associated macrophages polarization and natural killer cells activation. Such strategy paves a moderate way to remold TME without depleting CAFs and provides a powerful tool to design strategies of combinational hepatocellular carcinoma therapy.

Graphical Abstract

Insights into Melanoma Fibroblast Populations and Therapeutic Strategy Perspectives: Friends or Foes?

Cutaneous melanoma (CM) is an aggressive and highly metastatic solid tumor associated with drug resistance. Before 2011, despite therapies based on cytokines or molecules inhibiting DNA synthesis, metastatic melanoma led to patient death within 18 months from diagnosis. However, recent studies on bidirectional interactions between melanoma cells and tumor microenvironment (TME) have had a significant impact on the development of new therapeutic strategies represented by targeted therapy and immunotherapy. In particular, the heterogeneous stromal fibroblast populations, including fibroblasts, fibroblast aggregates, myofibroblasts, and melanoma associated fibroblasts (MAFs), represent the most abundant cell population of TME and regulate cancer growth differently. Therefore, in this perspective article, we have highlighted the different impacts of fibroblast populations on cancer development and growth. In particular, we focused on the role of MAFs in sustaining melanoma cell survival, proliferation, migration and invasion, drug resistance, and immunoregulation. The important role of constitutively activated MAFs in promoting CM growth and immunoediting makes this cell type a promising target for cancer therapy.