Characteristics and Significance of the Pre-metastatic Niche

Pericytes in hematogenous metastasis: mechanistic insights and therapeutic approaches

Metastasis, the leading cause of cancer-related deaths, underscores the critical need to understand its regulatory mechanisms to improve prevention and treatment strategies for late-stage tumors. Hematogenous dissemination is a key route of metastasis. However, as the gatekeeper of vessels, the role of pericytes in hematogenous metastasis remains largely unknown. In this review, we comprehensively explore the contributions of pericytes throughout the metastatic cascade, particularly their functions that extend beyond influencing tumor angiogenesis. Pericytes should not be perceived as passive bystanders, but rather as active participants in various stages of the metastatic cascade. Pericytes-targeted therapy may provide novel insights for preventing and treating advanced-stage tumor.

N6-methyladenosine-regulated exosome biogenesis orchestrates an immunosuppressive pre-metastatic niche in gastric cancer peritoneal metastasis

BACKGROUND

Gastric cancer peritoneal metastasis is clinically challenging, given the limited treatment options and poor prognosis. The molecular mechanisms that precede gastric cancer peritoneal metastasis, known as the pre-metastatic niche (PMN), and its relationship with N6-methyladenosine (m6A) modification remain unclear.

METHODS

We used 87 resected gastric cancer tissues and 4 public datasets to explore the association between methyltransferase-like 3 (METTL3) expression and gastric cancer peritoneal metastasis. Roles of m6A, exosomes, or macrophages in PMN formation were explored in immunocompetent mouse models through exosome treatments or macrophage modifications. Key genes and regulatory mechanisms were uncovered using mass spectrometry, RNA/miRNA sequencing, RNA-immunoprecipitation, dual-luciferase assays, and point mutations in the ras-related protein Rab-27A (RAB27A) in cells. Macrophage and T-cell functions were assessed using enzyme-linked immunosorbent assay, flow cytometry, and cytotoxicity assays.

RESULTS

METTL3 overexpression in gastric cancer cells enhanced RAB27A translation by methylating its mRNA A502 base, facilitated by its m6A "reader" YTH N6-methyladenosine RNA binding protein F1 (YTHDF1), and led to increased exosome biogenesis. The miRNA-17-92 cluster was enriched in METTL3-overexpressed cell-derived exosomes and targeted SRC kinase signaling inhibitor 1 (SRCIN1) to activate SRC proto-oncogene, non-receptor tyrosine kinase (SRC) signaling in peritoneal macrophages. Macrophage activation skewed cytokine production towards an immunosuppressive profile in the peritoneum, elevating the levels of interleukin (IL)-10 and tumor necrosis factor (TNF) and reducing the levels of IL-1 and IL-6. These cytokine shifts inhibited T cell proliferation and cytotoxic activities, which created an immunosuppressive PMN and led to peritoneal metastasis. The association between METTL3, macrophages, and peritoneal metastasis was verified in clinical samples.

CONCLUSIONS

Our study identified an intricate m6A-regulated mechanism of peritoneal PMN development that is mediated by exosome-promoted macrophages. These insights into gastric cancer peritoneal metastasis offer promising directions for translational research.

EYA3 regulation of NF-κB and CCL2 suppresses cytotoxic NK cells in the premetastatic niche to promote TNBC metastasis

Triple-negative breast cancer cells must evade immune surveillance to metastasize to distant sites, yet this process is not well understood. The Eyes absent (EYA) family of proteins, which are crucial for embryonic development, become dysregulated in cancer, where they have been shown to mediate proliferation, migration, and invasion. Our study reveals an unusual mechanism by which EYA3 reduces the presence of cytotoxic natural killer (NK) cells in the premetastatic niche (PMN) to enhance metastasis, independent of its effects on the primary tumor. We find that EYA3 up-regulates nuclear factor κB signaling to enhance CCL2 expression, which, in contrast to previous findings, suppresses cytotoxic NK cell activation in vitro and their infiltration into the PMN in vivo. These findings uncover an unexpected role for CCL2 in inhibiting NK cell responses at the PMN and suggest that targeting EYA3 could be an effective strategy to reactivate antitumor immune responses to inhibit metastasis.

Osteosarcoma cell-derived CCL2 facilitates lung metastasis via accumulation of tumor-associated macrophages

Osteosarcoma (OS) is the most common malignant tumor of bone in children and adolescents. Although lung metastasis is a major obstacle to improving the prognosis of OS patients, the underlying mechanism of lung metastasis of OS is poorly understood. Tumor-associated macrophages (TAMs) with M2-like characteristics are reportedly associated with lung metastasis and poor prognosis in OS patients. In this study, we investigated the metastasis-associated tumor microenvironment (TME) in orthotopic OS tumor models with non-metastatic and metastatic OS cells. Non-metastatic and metastatic tumor cells derived from mouse OS (Dunn and LM8) and human OS (HOS and 143B) were used to analyze the TME associated with lung metastasis in orthotopic OS tumor models. OS cell-derived secretion factors were identified by cytokine array and enzyme-linked immunosorbent assay (ELISA). Orthotopic tumor models with metastatic LM8 and 143B cells were analyzed to evaluate the therapeutic potential of a neutralizing antibody in the development of primary and metastatic tumors. Metastatic OS cells developed metastatic tumors with infiltration of M2-like TAMs in the lungs. Cytokine array and ELISA demonstrated that metastatic mouse and human OS cells commonly secreted CCL2, which was partially encapsulated in extracellular vesicles. In vivo experiments demonstrated that while primary tumor growth was unaffected, administration of CCL2-neutralizing antibody led to a significant suppression of lung metastasis and infiltration of M2-like TAMs in the lung tissue. Our results suggest that CCL2 plays a crucial role in promoting the lung metastasis of OS cells via accumulation of M2-like TAMs.

High extracellular matrix stiffness upregulates TNNT1 to awaken dormant tumor cells in liver metastatic niches of gastric cancer

BACKGROUND

Liver is one of the target organs bearing the most frequent distant metastasis of gastric cancer (GC), and patients with GC liver metastasis suffering from poor prognosis. According to "seed and soil" theory, important and complex interactions between disseminated tumor cells (DTCs) and metastasis tumor microenvironment (MTM) have played a vital role in waking the dormant DTCs and promoting their proliferation. We have discovered that the aberrantly activated cancer associated fibroblasts (CAFs) could significantly increase the enrichment and stiffness of extracellular matrix (ECM). ECM with high stiffness could facilitate the accumulation of Troponin T1, slow skeletal type (TNNT1) in cytoplasm for dormant DTCs awaking and proliferation.

METHODS

We set off from observing the stiffness of ECM around liver metastatic niches of GC and performed in vivo and in vitro study for further study. Based on the gained information, we plan to further unveil the underlying mechanism and explore the clinical transformation value using the ex-vivo and patient derived xenograft (PDX) model.

CONCLUSION

Our study aims to illustrate the relationship between ECM stiffness and tumor dormancy awakening in liver metastasis of GC and provide reliable theoretical and research basis for treatment of GC liver metastasis.

The role of plasma-derived small extracellular vesicles in pre-metastatic niche formation through modulation of macrophages in head and neck squamous cell carcinoma

BACKGROUND

Metastases are associated with poor survival in head and neck squamous cell carcinoma (HNSCC) patients and tumour-associated macrophages (TAMs) are important drivers in tumour progression and metastasis formation. Small extracellular vesicles (sEVs) are another important factor that contribute to systemic immunosuppression and pre-metastatic niche formation. Here, we investigate the effect of plasma sEVs from HNSCC patients on pre-metastatic niche formation, directly or through modulation of macrophages.

METHODS

Primary macrophages were incubated with sEVs from plasma of HNSCC patients or healthy donors (HD). RNA profiles and inflammatory properties of macrophages were evaluated. Direct and indirect effects of sEVs on chemotaxis, T cell activation, proliferation and epithelial-to-mesenchymal transition (EMT) of tumour cells were investigated.

RESULTS

sEVs of HNSCC patients and HD induced different RNA profiles in macrophages. sEVs induced apoptosis and inhibition of T cell activation, while tumour cells were attracted by sEV-treated macrophages, but not sEVs directly. Proliferation was inhibited by both, sEVs and supernatant of EV-treated macrophages in HNSCC. Additionally, EMT in tumour cells was reversed by HNSCC sEV-treated macrophages.

CONCLUSION

sEVs from plasma of HNSCC patients transformed macrophages into metastasis-promoting TAMs and inhibited anti-tumour T cells, highlighting the potential of sEVs and TAMs as targets for therapeutic approaches.

The Pre-metastatic Niche: How Cancer Stem Cell-Derived Exosomal MicroRNA Fit into the Puzzle

Cancer metastasis is a complicated biological process that critically affects cancer progression, patient outcomes, and treatment plans. A significant step in metastasis is the formation of a pre-metastatic niche (PMN). A small subset of cells within tumors, known as cancer stem cells (CSCs), possess unique characteristics including, differentiation into different cell types within the tumor, self-renewal, and resistance to conventional therapies, that enable them to initiate tumors and drive metastasis. PMN plays an important role in preparing secondary organs for the arrival and proliferation of CSCs, thereby facilitating metastasis. CSC-derived exosomes are crucial components in the complex interplay between CSCs and the tumor microenvironment. These exosomes function as transporters of various substances that can promote cancer progression, metastasis, and modulation of pre-metastatic environments by delivering microRNA (miRNA, miR) cargo. This review aims to illustrate how exosomal miRNAs (exo-miRs) secreted by CSCs can predispose PMN and promote angiogenesis and metastasis.

Role of Extracellular Vesicles in the Pathogenesis of Brain Metastasis

Extracellular vesicles (EVs) are small particles released by various cells, including cancer cells. They play a significant role in the development of different cancers, including brain metastasis. These EVs transport biomolecular materials such as RNA, DNA, and proteins from tumour cells to other cells, facilitating the spread of primary tumours to the brain tissue. EVs interact with the endothelial cells of the blood-brain barrier (BBB), compromising its integrity and allowing metastatic cells to pass through easily. Additionally, EVs interact with various cells in the brain's microenvironment, creating a conducive environment for incoming metastatic cells. They also influence the immune system within this premetastatic environment, promoting the growth of metastatic cells. This review paper focuses on the research regarding the role of EVs in the development of brain metastasis, including their impact on disrupting the BBB, preparing the premetastatic environment, and modulating the immune system. Furthermore, the paper discusses the potential of EVs as diagnostic and prognostic biomarkers for brain metastasis.

Tumor-derived exosomal LINC01812 induces M2 macrophage polarization to promote perineural invasion in cholangiocarcinoma

M2 macrophages play a critical role in the tumor microenvironment of invasive solid tumors. They are closely associated with perineural invasion (PNI) and are often linked to poor prognosis. In this context, tumor-derived exosomes serve as important mediators of intercellular communication. However, the relationship between tumor cell-induced M2 macrophages and PNI in cholangiocarcinoma remains unexplored. In this study, we utilized multiplex immunofluorescence and transcriptomic sequencing to demonstrate the upregulation of LINC01812 in cholangiocarcinoma tissues and its positive correlation with M2 macrophage infiltration. Exosomal lncRNA sequencing, exosome uptake experiments, RNA pull-down assays, and mass spectrometry analysis demonstrated that macrophages can internalize exosomal LINC01812 and promote the M2 phenotype in cholangiocarcinoma cells. Additionally, Transwell and in vitro cocultures with the dorsal root ganglia confirmed that the tumor microenvironment significantly enhances the nerve infiltration of cholangiocarcinoma cells via M2 macrophages. The findings of this study indicate that exosomes containing LINC01812 derived from cholangiocarcinoma can induce M2 macrophage polarization and facilitate nerve infiltration, thereby providing new potential therapeutic targets for managing PNI in cholangiocarcinoma.

The scRNA-sequencing landscape of pancreatic ductal adenocarcinoma revealed distinct cell populations associated with tumor initiation and progression

Pancreatic ductal adenocarcinoma (PDAC) stands as a formidable malignancy characterized by its profound lethality. The comprehensive analysis of the transcriptional landscape holds immense significance in understanding PDAC development and exploring novel treatment strategies. However, due to the firm consistency of pancreatic cancer samples, the dissociation of single cells and subsequent sequencing can be challenging. Here, we performed single-cell RNA sequencing (scRNA-seq) on 8 PDAC patients with different lymph node metastasis status. We first identified the crucial role of MMP1 in the transition from normal pancreatic cells to cancer cells. The knockdown of MMP1 in pancreatic cancer cell lines decreased the expression of ductal markers such as SOX9 while the overexpression of MMP1 in hTERT-HPNE increased the expression of ductal markers, suggesting its function of maintaining ductal identity. Secondly, we found a S100A2 + tumor subset which fueled lymph node metastasis in PDAC. The knockdown of S100A2 significantly reduced the motility of pancreatic cancer cell lines in both wound healing and transwell migration assays. While overexpression of S100A2 led to increased migratory capability. Moreover, overexpression of S100A2 in KPC1199, a mouse pancreatic cancer cell line, caused a larger tumor burden in a hemi-spleen injection model of liver metastasis. In addition, epithelial-mesenchymal transition-related genes were decreased by S100A2 knockdown revealed by bulk RNA sequencing. We also identified several pivotal contributors to the pro-tumor microenvironment, notably OMD + fibroblast and CCL2 + macrophage. As a result, our study provides valuable insights for early detection of PDAC and promising therapeutic targets for combatting lymph node metastasis.

Exploring molecular and cellular mechanisms of Pre-Metastatic niche in renal cell carcinoma

Renal cell carcinoma (RCC) is among the most frequently occurring types of cancer, and its metastasis is a major contributor to its elevated mortality. Before the primary tumor metastasizes to secondary or distant organs, it remodels the microenvironment of these sites, creating a pre-metastatic niche (PMN) conducive to the colonization and growth of metastatic tumors. RCC releases a variety of biomolecules that induce angiogenesis, alter vascular permeability, modulate immune cells to create an immunosuppressive microenvironment, affect extracellular matrix remodeling and metabolic reprogramming, and determine the organotropism of metastasis through different signaling pathways. This review summarizes the principal processes and mechanisms underlying the formation of the premetastatic niche in RCC. Additionally, we emphasize the significance and potential of targeting PMNs for the prevention and treatment of tumor metastasis in future therapeutic approaches. Finally, we summarized the currently potential targeted strategies for detecting and treating PMN in RCC and provide a roadmap for further in-depth studies on PMN in RCC.

Advances in the roles and molecular mechanisms of exosomal circular RNAs in regulating the pre-metastatic niche of tumors

Metastasis remains a major cause of morbidity and mortality in patients with malignant tumors. The pre-metastatic niche is a prerequisite for distant metastasis driven by primary tumors. Circular RNAs (circRNAs), a class of single-stranded closed non-coding RNAs, exhibit high stability, evolutionary conservation, and cell-type specificity. Exosomes, as natural carriers of circRNAs, mediate intercellular communication and contribute to the formation of the pre-metastatic niche; however, the mechanisms by which they do so remain incompletely understood. This review summarizes the biological characteristics and functions of exosomal circRNAs and outlines the molecular pathways through which they shape the tumor pre-metastatic microenvironment, with emphasis on immunosuppression, vascular permeability, extracellular matrix remodeling, and lymphangiogenesis. This is the first review to focus on the functional roles and molecular mechanisms of exosomal circRNAs in pre-metastatic niche regulation, providing a basis for the development of therapeutic strategies targeting metastatic progression.

Lung-specific metastasis: the coevolution of tumor cells and lung microenvironment

The vast majority of cancer-related deaths are attributed to metastasis. The lung, being a common site for cancer metastasis, is highly prone to being a target for multiple cancer types and causes a heavy disease burden. Accumulating evidence has demonstrated that tumor metastasis necessitates continuous interactions between tumor cells and distant metastatic niches. Nevertheless, a comprehensive elucidation of the underlying mechanisms governing lung-specific metastasis still poses a formidable challenge. In this review, we depict the lung susceptibility and the molecular profiles of tumors with the potential for lung metastasis. Under the conceptual framework of "Reciprocal Tumor-Lung Metastatic Symbiosis" (RTLMS), we mechanistically delineate the bidirectional regulatory dynamics and coevolutionary adaptation between tumor cells and distal pulmonary niches during lung-specific metastasis, including the induction of pre-metastatic-niches, positive responses of the lung, tumor colonization, dormancy, and reawakening. An enhanced understanding of the latest mechanisms is essential for developing targeted strategies to counteract lung-specific metastasis.

Hypoxia LUAD H1975 cell-derived exosomal miR-671-3p promotes angiogenesis via regulating KLF2-VEGFR2 axis

For solid tumors, hypoxia is associated with disease aggressiveness and poor outcomes. In addition to undergoing broad intracellular molecular and metabolic adaptations, hypoxic tumor cells extensively communicate with their microenvironments to facilitate conditions favorable for their survival, growth, and metastasis. This communication is mediated by diverse secretory factors, including exosomes (extracellular vesicles of endosomal origin). Exosomal cargo is altered considerably by hypoxia, with significant impacts on tumor-cell communication with both local and distant microenvironments. Exosomes released by cancer cells influence the tumor environment to accelerate metastasis. While tumor-derived exosomes have been identified as a major driver of premetastatic niche formation at distant sites, this mechanism in lung adenocarcinoma (LUAD) remains unclear. We found that miR-671-3p in exosomes derived from H1975 under hypoxic conditions target Krüppel-like factor 2 (KLF2) to regulate VEGFR2 expression in endothelial cells to promote angiogenesis. In addition, miR-671-3p is expressed at high levels in circulating exosomes isolated from patients with LUAD. Our study suggests that exosome miR-671-3p is involved in the formation of premetastatic niche and may serve as a blood-based biomarker for LUAD metastasis.

Biological mechanisms and immunotherapy of brain metastases in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality worldwide, with Brain Metastases serving as a significant adverse prognostic factor. The blood-brain barrier poses a substantial challenge in the treatment of brain metastases, as it restricts the penetration of many anticancer agents. Novel immunotherapy, such as immune checkpoint inhibitors (ICIs) have emerged as promising treatment for NSCLC and its associated brain metastases. This review summarizes the biological mechanism underlying NSCLC brain metastases and provides an overview of the current landscape of immunotherapy, exploring the mechanism of action and clinical applications of these advanced treatments.

From surfing to diving into the tumor microenvironment through multiparametric imaging mass cytometry

The tumor microenvironment (TME) is a complex ecosystem where malignant and non-malignant cells cooperate and interact determining cancer progression. Cell abundance, phenotype and localization within the TME vary over tumor development and in response to therapeutic interventions. Therefore, increasing our knowledge of the spatiotemporal changes in the tumor ecosystem architecture is of importance to better understand the etiologic development of the neoplastic diseases. Imaging Mass Cytometry (IMC) represents the elective multiplexed imaging technology enabling the in-situ analysis of up to 43 different protein markers for in-depth phenotypic and spatial investigation of cells in their preserved microenvironment. IMC is currently applied in cancer research to define the composition of the cellular landscape and to identify biomarkers of predictive and prognostic significance with relevance in mechanisms of drug resistance. Herein, we describe the general principles and experimental workflow of IMC raising the informative potential in preclinical and clinical cancer research.

Mechanistic insight for T-cell exclusion by cancer-associated fibroblasts in human lung cancer

The tumor stroma consists mainly of extracellular matrix, fibroblasts, immune cells, and vasculature. Its structure and functions are altered during malignancy: tumor cells transform fibroblasts into cancer-associated fibroblasts, which exhibit immunosuppressive activities on which growth and metastasis depend. These include exclusion of immune cells from the tumor nest, cancer progression, and inhibition of T-cell-based immunotherapy. To understand these complex interactions, we measure the density of different cell types in the stroma using immunohistochemistry techniques on tumor samples from lung cancer patients. We incorporate these data into a minimal dynamical system, explore the variety of outcomes, and finally establish a spatio-temporal model that explains the cell distribution. We reproduce that cancer-associated fibroblasts act as a barrier to tumor expansion, but also reduce the efficiency of the immune response. Our conclusion is that the final outcome depends on the parameter values for each patient and leads to either tumor invasion, persistence, or eradication as a result of the interplay between cancer cell growth, T-cell cytotoxicity, and fibroblast activity. However, despite the existence of a wide range of scenarios, distinct trajectories, and patterns allow quantitative predictions that may help in the selection of new therapies and personalized protocols.

Cuproplasia and cuproptosis in hepatocellular carcinoma: mechanisms, relationship and potential role in tumor microenvironment and treatment

BACKGROUND

Hepatocellular carcinoma (HCC) is the main phenotype of liver cancer with a poor prognosis. Copper is vital in liver function, and HCC cells rely on it for growth and metastasis, leading to cuproplasia. Excessive copper can induce cell death, termed cuproptosis. Tumor microenvironment (TME) is pivotal in HCC, especially in immunotherapy, and copper is closely related to the TME pathogenesis. However, how these two mechanisms contribute to the TME is intriguing.

MAIN BODY

We conducted the latest progress literature on cuproplasia and cuproptosis in HCC, and summarized their specific roles in TME and treatment strategies. The mechanisms of cuproplasia and cuproptosis and their relationship and role in TME have been deeply summarized. Cuproplasia fosters TME formation, angiogenesis, and metastasis, whereas cuproptosis may alleviate mitochondrial dysfunction and hypoxic conditions in the TME. Inhibiting cuproplasia and enhancing cuproptosis in HCC are essential for achieving therapeutic efficacy in HCC.

CONCLUSION

An in-depth analysis of cuproplasia and cuproptosis mechanisms within the TME of HCC unveils their opposing nature and their impact on copper regulation. Grasping the equilibrium between these two factors is crucial for a deeper understanding of HCC mechanisms to shed light on novel directions in treating HCC.

Lipid metabolic reprogramming and associated ferroptosis in osteosarcoma: From molecular mechanisms to potential targets

Osteosarcoma is a common bone tumor in adolescents, which is characterized by lipid metabolism disorders and plays a key role in tumorigenesis and disease progression. Ferroptosis is an iron-dependent form of programmed cell death associated with lipid peroxidation. This review provides an in-depth analysis of the complex relationship between lipid metabolic reprogramming and associated ferroptosis in OS from the perspective of metabolic enzymes and metabolites. We discussed the molecular basis of lipid uptake, synthesis, storage, lipolysis, and the tumor microenvironment, as well as their significance in OS development. Key enzymes such as adenosine triphosphate-citrate lyase (ACLY), acetyl-CoA synthetase 2 (ACSS2), fatty acid synthase (FASN) and stearoyl-CoA desaturase-1 (SCD1) are overexpressed in OS and associated with poor prognosis. Based on specific changes in metabolic processes, this review highlights potential therapeutic targets in the lipid metabolism and ferroptosis pathways, and in particular the HMG-CoA reductase inhibitor simvastatin has shown potential in inducing apoptosis and inhibiting OS metastasis. Targeting these pathways provides new strategies for the treatment of OS. However, challenges such as the complexity of drug development and metabolic interactions must be overcome. A comprehensive understanding of the interplay between dysregulation of lipid metabolism and ferroptosis is essential for the development of innovative and effective therapies for OS, with the ultimate goal of improving patient outcomes.

Baseline Inflammatory Burden Index Predicts Primary Resistance to Combinations of ICIs With Chemotherapy in Patients With HER-2-Negative Advanced Gastric Cancer

PURPOSE

Combinations of immune checkpoint inhibitors (ICIs) and chemotherapy have become the standard first-line treatment for human epidermal growth factor receptor 2 (HER-2)-negative advanced gastric cancer. However, primary resistance remains a challenge, with no effective biomarkers available for its prediction. This retrospective study explores the relationship between the baseline inflammatory burden index (IBI) and primary resistance in such context.

MATERIALS AND METHODS

We analyzed 62 patients with HER-2-negative advanced gastric cancer who received ICIs and chemotherapy as their first-line treatment. The IBI was calculated as follows: C-reactive protein (mg/L) × neutrophil count (10³/mm³)/lymphocyte count (10³/mm³). Based on disease progression within 6 months, patients were categorized into the primary resistant or the control group. We compared baseline characteristics and IBI scores between the groups and assessed the predictive value of the IBI using the receiver operating characteristic curve. Both univariate and multivariate binary logistic regression analyses were conducted to identify factors influencing primary resistance.

RESULTS

Nineteen patients were included in the primary resistance group, and forty-three patients were included in the control group. The IBI was significantly higher in the resistant group compared to the control group (P<0.01). The area under the curve for the IBI was 0.82, indicating a strong predictive value. Multivariate analysis identified the IBI as an independent predictor of primary resistance (P=0.014).

CONCLUSIONS

The baseline IBI holds promise as a predictor of primary resistance to combined ICIs and chemotherapy in patients with HER-2-negative advanced gastric cancer.

Nanoparticles for Photodynamic Therapy of Breast Cancer: A Review of Recent Studies

Photodynamic therapy (PDT) is a therapeutic method based on the interaction between light and a photosensitizer. Supported by nanoparticles, this method represents a promising interdisciplinary approach for the treatment of many diseases. This article reviews the latest 2024 developments in the design and applications of nanoparticles dedicated to stand-alone PDT of breast cancer. Strategies to improve therapeutic efficacy by enhancing reactive oxygen species (ROS) production, precise delivery of photosensitizers and their stabilization in the systemic circulation are discussed, among others. Results from preclinical studies indicate significant improvements in therapeutic efficacy, including inhibition of tumor growth, reduction in metastasis and improvement of the immune microenvironment. The potential of these technologies to expand PDT applications in medicine and the need for further clinical trials to confirm their safety and efficacy are highlighted.

Apelin/APJ: Another Player in the Cancer Biology Network

The apelinergic system exerts multiple biological activities in human pathologies, including cancer. Overactivation of apelin/APJ, which has been detected in many malignant tumors, and the strong correlation with progression-free and overall survival, suggested the role of an oncogene for the apelin gene. Emerging evidence sheds new light on the effects of apelin on cellular functions and homeostasis in cancer cells and supports a direct role for this pathway on different hallmarks of cancer: "sustaining proliferative signaling", "resisting cell death", "activating invasion and metastasis", "inducing/accessing vasculature", "reprogramming cellular metabolism", "avoiding immune destruction" and "tumor-promoting inflammation", and "enabling replicative immortality". This article reviews the currently available literature on the intracellular processes regulated by apelin/APJ, focusing on those pathways correlated with tumor development and progression. Furthermore, the association between the activity of the apelinergic axis and the resistance of cancer cells to oncologic treatments (chemotherapy, immunotherapy, radiation) suggests apelin/APJ as a possible target to potentiate traditional therapies, as well as to develop diagnostic and prognostic applications. This issue will be also covered in the review.

The Role of Inflammation in Cancer: Mechanisms of Tumor Initiation, Progression, and Metastasis

Inflammation is an essential component of the immune response that protects the host against pathogens and facilitates tissue repair. Chronic inflammation is a critical factor in cancer development and progression. It affects every stage of tumor development, from initiation and promotion to invasion and metastasis. Tumors often create an inflammatory microenvironment that induces angiogenesis, immune suppression, and malignant growth. Immune cells within the tumor microenvironment interact actively with cancer cells, which drives progression through complex molecular mechanisms. Chronic inflammation is triggered by factors such as infections, obesity, and environmental toxins and is strongly linked to increased cancer risk. However, acute inflammatory responses can sometimes boost antitumor immunity; thus, inflammation presents both challenges and opportunities for therapeutic intervention. This review examines how inflammation contributes to tumor biology, emphasizing its dual role as a critical factor in tumorigenesis and as a potential therapeutic target.

Colorectal cancer cells-derived exosomal miR-188-3p promotes liver metastasis by creating a pre-metastatic niche via activation of hepatic stellate cells

BACKGROUND/AIM

Metastasis is the leading cause of mortality for colorectal cancer (CRC). Cancer-derived exosomes are widely recognized as the primary catalysts behind the development of pre-metastasis niche (PMN) in distal sites. However, the exact mechanism behind this process in CRC remains elusive. This study aimed to investigate the function and mechanisms underlying the role of exosomal miR-188-3p in activating hepatic stellate cells (HSCs) to develop the PMN and promote liver metastasis.

METHODS

We extracted exosomes from CRC cells using ultracentrifugation. Exosomes were identified using transmission electron microscopy, nanoparticle tracking analysis, and Western blot. Exosome uptake was assessed using fluorescence tracing, exosome PKH67 staining, and real-time quantitative PCR. The effects of CRC cell-derived exosomes on HSCs migration were evaluated using Transwell migration and wound healing assays. Key differentially expressed miRNAs were screened from the GEO database, and bioinformatics prediction along with dual-luciferase reporter assays were used to identify downstream target genes of miR-188-3p. Downstream related proteins of the target genes were detected by Western blot. In vivo, the distribution of exosomes and activation of HSCs in the liver were explored by tail vein injection of exosomes into nude mice. Further, the impact of exosomal miR-188-3p on liver metastasis was investigated using a spleen injection liver metastasis model. Finally, the expression levels of miR-188-3p in exosomes from CRC patient plasma were determined by real-time quantitative PCR, and the relationship between the expression of miR-188-3p in plasma exosomes and CRC prognosis was analyzed.

RESULTS

The expression level of miR-188-3p within plasma exosomes demonstrated a statistically significant increase in CRC with liver metastasis compared to those without liver metastases. We also demonstrated the transferability of miR-188-3p from CRC cells to HSCs cells via the exosomes. Exosomal miR-188-3p plays a pivotal role in orchestrating the establishment of PMN through targeting PHLPP2 to activate HSCs before tumor metastasis. Exosomal miR-188-3p was found to actively foster in vivo metastasis of CRC. Additionally, plasma exosomal miR-188-3p potentially serves as a viable blood-based biomarker for CRLM.

CONCLUSION

Exosomal miR-188-3p derived from CRC cells can promote liver metastasis by activating HSCs to form a PMN through targeting PHLPP2 to activate the AKT/mTOR pathway. These results offer a new perspective on the mechanisms driving CRLM.

Liquid biopsies in cancer

Cancer ranks among the most lethal diseases worldwide. Tissue biopsy is currently the primary method for the diagnosis and biological analysis of various solid tumors. However, this method has some disadvantages related to insufficient tissue specimen collection and intratumoral heterogeneity. Liquid biopsy is a noninvasive approach for identifying cancer-related biomarkers in peripheral blood, which allows for repetitive sampling across multiple time points. In the field of liquid biopsy, representative biomarkers include circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and exosomes. Many studies have evaluated the prognostic and predictive roles of CTCs and ctDNA in various solid tumors. Although these studies have limitations, the results of most studies appear to consistently demonstrate the correlations of high CTC counts and ctDNA mutations with lower survival rates in cancer patients. Similarly, a reduction in CTC counts throughout therapy may be a potential prognostic indicator related to treatment response in advanced cancer patients. Moreover, the biochemical characteristics of CTCs and ctDNA can provide information about tumor biology as well as resistance mechanisms against targeted therapy. This review discusses the current clinical applications of liquid biopsy in cancer patients, emphasizing its possible utility in outcome prediction and treatment decision-making.

Whole genome sequencing of 378 prostate cancer metastases reveals tissue selectivity for mismatch deficiency with potential therapeutic implications

BACKGROUND

Survival of patients with metastatic castration-resistant prostate cancer (mCRPC) depends on the site of metastatic dissemination.

METHODS

Patients with mCRPC were prospectively included in the CPCT-02 metastatic site biopsy study. We evaluated whole genome sequencing (WGS) of 378 mCRPC metastases to understand the genetic traits that affect metastatic site distribution.

RESULTS

Our findings revealed that RB1, PIK3CA, JAK1, RNF43, and TP53 mutations are the most frequent genetic determinants associated with site selectivity for metastatic outgrowth. Furthermore, we explored mutations in the non-coding genome and found that androgen receptor (AR) chromatin binding sites implicated in metastatic prostate cancer differ in mutation frequencies between metastatic sites, converging on pathways that impact DNA repair. Notably, liver and visceral metastases have a higher tumor mutational load (TML) than bone and lymph node metastases, independent of genetic traits associated with neuroendocrine differentiation. We found that TML is strongly associated with DNA mismatch repair (MMR)-deficiency features in these organs.

CONCLUSIONS

Our results revealed gene mutations that are significantly associated with metastatic site selectivity and that frequencies of non-coding mutations at AR chromatin binding sites differ between metastatic sites. Immunotherapeutics are thus far unsuccessful in unselected mCRPC patients. We found a higher TML in liver and visceral metastases compared to bone and lymph node metastases. As immunotherapeutics response is associated with mutational burden, these findings may assist in selecting mCRPC patients for immunotherapy treatment based on organs affected by metastatic disease.

TRIAL REGISTRATION NUMBER

NCT01855477.

Understanding pre-metastatic niche formation: implications for colorectal cancer liver metastasis

The liver is the most commonly metastasized organ in colorectal cancer (CRC), and distant metastasis is the primary cause of mortality from CRC. In recent years, researchers have discovered that tumor cells create a "pre-metastatic niche (PMN)" favorable to metastasis before reaching the metastatic location. This review discusses the many processes and mechanisms that lead to PMN formation in CRC, including gut microbiota, stem cell stimulation, immunocyte interactions, and the induction of extracellular vesicles that carry important information. It examines research methods and diagnostic and therapeutic approaches for treating metastatic CRC with PMN. The crucial significance of PMN formation in metastatic CRC is also highlighted.

Pyruvate Kinase M1/2 Proteoformics for Accurate Insights into Energy Metabolism Abnormity to Promote the Overall Management of Ovarian Cancer Towards Predictive, Preventive, and Personalized Medicine Approaches

Ovarian cancer (OC) is a global health problem that frequently presents at advanced stages, is predisposed to recurrence, readily develops resistance to platinum-based drugs, and has a low survival rate. Predictive, preventive, and personalized medicine (PPPM/3PM) offers an integrated solution with the use of genetic, proteomic, and metabolic biomarkers to identify high-risk individuals for early detection. Metabolic reprogramming is one of the key strategies employed by tumor cells to adapt to the microenvironment and support unlimited proliferation. Pyruvate kinases M1 and M2 (PKM1/2) are encoded by the PKM gene, a pivotal enzyme in the last step of the glycolytic pathway, which is at the crossroads of aerobic oxidation and the Warburg effect to serve as a potential regulator of glucose metabolism and influence cellular energy production and metabolic reprogramming. Commonly, the ratio of PKM1-to-PKM2 is changed in tumors compared to normal controls, and PKM2 is highly expressed in OC to induce a high glycolysis rate and participate in the malignant invasion and metastatic characteristics of cancer cells with epithelial/mesenchymal transition (EMT). PKM2 inhibitors suppress the migration and growth of OC cells by interfering with the Warburg effect. Proteoforms are the final structural and functional forms of a gene/protein, and the canonical protein PKM contains all proteoforms encoded by the same PKM gene. The complexity of PKM can be elucidated by proteoformics. The OC-specific PKM proteoform might represent a specific target for therapeutic interventions against OC. In the framework of PPPM/3PM, the OC-specific PKM proteoform might be the early warning and prognosis biomarker. It is important to clarify the molecular mechanisms of PKM proteoforms in cancer metabolism. This review analyzes the expression, function, and molecular mechanisms of PKM proteoforms in OC, which help identify specific biomarkers for OC.

Hidden messages in fluids: A review of clinical and fundamental perspectives on post-lymph node dissection drains

In recent years, there has been a growing interest in liquid biopsy due to its non-invasive diagnostic value. Postoperative drainage fluid (PDF) is the fluid exudate from the wound site following lymph node dissection. PDF is regarded as a medical waste with no specific clinical significance. Nevertheless, the liquid biopsy of PDF may enable the reuse of this fluid. PDF contains a variety of body fluids, including blood and lymph. PDF contains a variety of biological components, including cytokines, extracellular vesicles (EVs), proteins, nucleic acids, cells and bacteria. These components are indicative of the postoperative inflammatory response, the immune response and the therapeutic response. In this review, we examine the current state of research in the field of liquid biopsy in PDF, elucidating how the analysis of its components can assess the prognosis of patients after lymph node dissection, monitor real-time changes in patient status, and identify new biomarkers and potential therapeutic targets.

Liver Extracellular Matrix in Colorectal Liver Metastasis

The liver is the most common site of metastasis of colorectal cancer (CRC), and colorectal liver metastasis is one of the major causes of CRC-related deaths worldwide. The tumor microenvironment, particularly the extracellular matrix (ECM), plays a critical role in CRC metastasis and chemoresistance. Based on findings from clinical and basic research, this review attempts to offer a complete understanding of the role of the ECM in colorectal liver metastasis and to suggest potential ways for therapeutic intervention. First, the ECMs' role in regulating cancer cell fate is explored. We then discuss the hepatic ECM fingerprint and its influence on the metastatic behavior of CRC cells, highlighting key molecular interactions that promote metastasis. In addition, we examine how changes in the ECM within the metastatic niche contribute to chemoresistance, focusing on ECM remodeling by ECM stiffening and the activation of specific signaling pathways. Understanding these mechanisms is crucial for the development of novel strategies to overcome metastasis and improve outcomes for CRC patients.

Focal adhesion in the tumour metastasis: from molecular mechanisms to therapeutic targets

The tumour microenvironment is the "hotbed" of tumour cells, providing abundant extracellular support for growth and metastasis. However, the tumour microenvironment is not static and is constantly remodelled by a variety of cellular components, including tumour cells, through mechanical, biological and chemical means to promote metastasis. Focal adhesion plays an important role in cell-extracellular matrix adhesion. An in-depth exploration of the role of focal adhesion in tumour metastasis, especially their contribution at the biomechanical level, is an important direction of current research. In this review, we first summarize the assembly of focal adhesions and explore their kinetics in tumour cells. Then, we describe in detail the role of focal adhesion in various stages of tumour metastasis, especially its key functions in cell migration, invasion, and matrix remodelling. Finally, we describe the anti-tumour strategies targeting focal adhesion and the current progress in the development of some inhibitors against focal adhesion proteins. In this paper, we summarize for the first time that focal adhesion play a positive feedback role in pro-tumour metastatic matrix remodelling by summarizing the five processes of focal adhesion assembly in a multidimensional way. It is beneficial for researchers to have a deeper understanding of the role of focal adhesion in the biological behaviour of tumour metastasis and the potential of focal adhesion as a therapeutic target, providing new ideas for the prevention and treatment of metastases.

Molecular Underpinnings of Brain Metastases

Brain metastases are the most commonly diagnosed type of central nervous system tumor, yet the mechanisms of their occurrence are still widely unknown. Lung cancer, breast cancer, and melanoma are the most common etiologies, but renal and colorectal cancers have also been described as metastasizing to the brain. Regardless of their origin, there are common mechanisms for progression to all types of brain metastases, such as the creation of a suitable tumor microenvironment in the brain, priming of tumor cells, adaptations to survive spreading in lymphatic and blood vessels, and development of mechanisms to penetrate the blood-brain barrier. However, there are complex genetic and molecular interactions that are specific to every type of primary tumor, making the understanding of the metastatic progression of tumors to the brain a challenging field of study. In this review, we aim to summarize current knowledge on the pathophysiology of brain metastases, from specific genetic characteristics of commonly metastatic tumors to the molecular and cellular mechanisms involved in progression to the central nervous system. We also briefly discuss current challenges in targeted therapies for brain metastases and how there is still a gap in knowledge that needs to be overcome to improve patient outcomes.

Design Principles of an Engineered Metastatic Niche for Monitoring of Cancer Progression

Across many types of cancer, metastatic disease is associated with a substantial decrease in 5-year survival rates relative to only a localized primary tumor. Many patients self-report metastatic disease due to disruption of normal organ or tissue function, and earlier detection could enable treatment with a lower burden of disease. We have previously reported a subcutaneous biomaterial implant for early detection by serving as an engineered metastatic niche, which has been reported to recruit tumor cells before colonization of solid organs. In this report, we investigated the design principles of the scaffold and defined the conditions for use in disease detection. Using the metastatic 4T1 triple-negative breast cancer model, we identified that a porous structure was essential to capture tumor and immune cells. Scaffolds of multiple diameters were investigated for their ability to serve as a metastatic niche, with a porous scaffold with a diameter as small as 2 mm identifying disease accurately. Additionally, scaffolds that had been in vivo for 1-5 weeks were able to identify disease accurately. Finally, the sensitivity of the scaffold relative to liquid biopsies was analyzed, with scaffolds accurately detecting disease at earlier time points than liquid biopsy. Collectively, these studies inform the design principles and use conditions for porous scaffolds to detect metastatic disease.

Immunological Pre-Metastatic Niche in Dogs With Naturally Occurring Osteosarcoma

Pre-metastatic niche (PMN) formation is essential for metastatic development and drives organotropism. Tumour-derived extracellular vesicles and soluble factors remodel the microenvironment of distant metastatic organs before subsequent metastasis. Dogs with osteosarcoma (OS) have proven to be excellent disease models for their human companions. Here, we show evidence of PMN formation in dogs with OS before metastasis. We necropsied and sampled lung tissues from dogs with naturally occurring treatment-naïve OS (n = 15) and control dogs without cancer (n = 10). We further divided dogs with OS into those having lung metastases (n = 5) and those without (n = 10). We stained formalin-fixed paraffin-embedded tissues using multiplex immunofluorescence to quantify the number of bone marrow-derived cells, monocytes and macrophages in the lung samples from each dog. The numbers of CD204+ macrophages, CD206+ macrophages and monocytes and CD11d+ bone marrow-derived cells (BMDCs) were significantly higher in the pre-metastatic lung of dogs with OS (n = 10) than in control dogs without cancer (n = 10). Furthermore, the total nucleated cell (DAPI+) density was higher before metastasis than in healthy lungs. In dogs with established metastases, the number of CD11d+ BMDCs was significantly lower than in the pre-metastatic lung, suggesting this recruitment is transient. Our study provides evidence of PMN existence in a naturally occurring cancer model similar to those observed in pre-clinical murine models. BMDCs are recruited to the lungs before metastases have developed. Dogs with OS may represent ideal candidates for assessing new PMN-targeting therapies.

Fibrinogen: A new player and target on the formation of pre-metastatic niche in tumor metastasis

Tumor metastasis involves a series of complex and coordinated processes, which is the main cause of patient death and still a significant challenge in cancer treatment. Pre-metastatic niches (PMN), a specialized microenvironment that develops in distant organs prior to the arrival of metastatic cancer cells, plays a crucial role in driving tumor metastasis. The development of PMN depends on a complex series of cellular and molecular components including tumor-derived factors, bone marrow-derived cells, resident immune cells, and extracellular matrix. Fibrinogen, a key factor in the typical blood clotting process, is related to tumor metastasis and prognosis, according to a growing body of evidence in recent years. Fibrinogen has emerged as an important factor in mediating the formation of tumor microenvironment. Nevertheless, a clear and detailed mechanism by which fibrinogen promotes tumor metastasis remains unknown. In this review, we first explore the roles of fibrinogen in the development of PMN from four perspectives: immunosuppression, inflammation, angiogenesis, and extracellular matrix remodeling. We highlight the significance of fibrinogen in shaping PMN and discuss its potential therapeutic values, opening new avenues for targeting fibrinogen to prevent or treat metastasis.

Liquid biopsy entering clinical practice: Past discoveries, current insights, and future innovations

In recent years, liquid biopsy has gained prominence as an emerging biomarker in cancer research, providing critical insights into tumor biology and metastasis. Technological advancements have enabled its integration into clinical practice, with ongoing trials demonstrating encouraging outcomes. Key applications of liquid biopsy include early cancer detection, cancer staging, prognosis evaluation, and real-time monitoring of tumor progression to optimize treatment decisions. In this review, we present a comprehensive conceptual framework for liquid biopsy, discuss the challenges in its research and clinical application, and highlight its significant potential in identifying therapeutic targets and resistance mechanisms across various cancer types. Furthermore, we explore the emerging role of liquid biopsy-based multicancer screening, which has shown promising advancements. Looking ahead, standardization, multi-omics coanalysis, and the advancement of precision medicine and personalized treatments are expected to drive the future development and integration of liquid biopsy into routine clinical workflows, enhancing cancer diagnosis and treatment management.

Distant metastasis of oral squamous cell carcinoma: immune escape mechanism and new perspectives on treatment

Oral squamous cell carcinoma (OSCC) is frequently observed as the predominant malignancy affecting the oral cavity, with distant metastasis greatly affecting the treatment and long-term outlook for individuals with OSCC. Immune checkpoint inhibitors are a highly promising cancer treatment strategy currently available, but they are only successful for a small fraction of individuals with OSCC. Due to the insufficient understanding of the immune escape mechanisms in OSCC, coupled with disappointing treatment outcomes for patients with highly heterogeneous metastatic diseases, there is an urgent need for further exploration of immune target therapy strategies. This review discusses the mechanisms by which OSCC cells evade immune surveillance and attack, focusing on four aspects: metastasis-initiating cells, increased immune suppression, immune escape of dormant cells, and immune stromal crosstalk during metastasis. Additionally, we explore new areas in immune therapy for OSCC. In summary, our investigation offers fresh perspectives on the relationship between the tumor microenvironment and immune molecules, highlighting the importance of overcoming immune evasion for the development of novel therapies to manage OSCC metastasis and enhance patient outcomes.

Breast cancer stem cell-derived exosomal lnc-PDGFD induces fibroblast-niche formation and promotes lung metastasis

Triple-negative breast cancer (TNBC) is the most aggressive subtype with high metastatic potential and lack of therapeutic targets. Breast cancer stem cells (BCSCs) are enriched in TNBC and contribute to its metastatic propensity. Accumulating evidence suggests that cancer-derived exosomes are key drivers of premetastatic niche formation in distal organs. However, the function and underlying mechanism of BCSC-derived exosomes in TNBC metastasis remain elusive. Here, we demonstrated that BCSC-derived exosomes exhibit a greater capacity to activate fibroblasts and promote TNBC cell metastasis to the lung than non-BCSC-derived exosomes. Additionally, we found that upregulation of exosomal long non-coding RNA platelet derived growth factor D (lnc-PDGFD) expression in BCSCs is responsible for fibroblast activation through YBX1/NF-kB signaling in the lung. Activated fibroblasts further promote tumor progression by secreting IL-11. Taken together, BCSC-derived exosomes enriched with lnc-PDGFD could activate fibroblasts, thereby facilitating lung metastasis in TNBC patients. These results provide new insights into the mechanism of TNBC metastasis to the lung.

Regulation of metastatic organotropism

Metastasis is responsible for most cancer-related deaths. Different cancers have their own preferential sites of metastases, a phenomenon termed metastatic organotropism. The mechanisms underlying organotropism are multifactorial and include the generation of a pre-metastatic niche (PMN), metastatic homing, colonization, dormancy, and metastatic outgrowth. Historically, studies of metastatic organotropism have been limited by a lack of models allowing direct comparison of cells exhibiting different patterns of tropism. However, new innovative models and large-scale sequencing efforts have propelled organotropism research. Herein, we summarize the recent discoveries in metastatic organotropism regulation, focusing on lung, liver, brain, and bone tropism. We discuss how emerging technologies are continuing to improve our ability to model and, hopefully, predict and treat organotropism.

Exosomes: a double-edged sword in cancer immunotherapy

Over the past few decades, immunotherapy has emerged as a powerful strategy to overcome the limitations of conventional cancer treatments. The use of extracellular vesicles, particularly exosomes, which carry cargoes capable of modulating the immune response, has been extensively explored as a potential therapeutic approach in cancer immunotherapy. Exosomes can deliver their cargo to target cells, thereby influencing their phenotype and immunomodulatory functions. They exhibit either immunosuppressive or immune-activating characteristics, depending on their internal contents. These exosomes originate from diverse cell sources, and their internal contents can vary, suggesting that there may be a delicate balance between immune suppression and stimulation when utilizing them for immunotherapy. Therefore, a thorough understanding of the molecular mechanisms underlying the role of exosomes in cancer progression is essential. This review focuses on the molecular mechanisms driving exosome function and their impact on the tumor microenvironment (TME), highlighting the intricate balance between immune suppression and activation that must be navigated in exosome-based therapies. Additionally, it underscores the challenges and ongoing efforts to optimize exosome-based immunotherapies, thereby making a significant contribution to the advancement of cancer immunotherapy research.

Vascular-Associated Mononuclear Phagocytes: First-Line Soldiers Ambushing Metastasis

Mononuclear phagocytes (MPs), which consist of dendritic cells, monocytes, and macrophages, are distributed throughout the body and actively eliminate invading microorganisms and abnormal cells. Depending on the local microenvironment, MPs manifest considerably various lifespans and phenotypes to maintain tissue homeostasis. Vascular-associated mononuclear phagocytes (VaMPs) are the special subsets of MPs that are localized either within the lumen side or on the apical surface of vessels, acting as the critical sentinels to recognize and defend against disseminated tumor cells. In this review, we introduce three major types of VaMPs, patrolling monocytes, Kupffer cells, and perivascular macrophages, and discuss their emerging roles in immunosurveillance during incipient metastasis. We also explore the roles of lineage-determining transcription factors and cell surface receptors that endow VaMPs with potent anti-tumor activity. Finally, we highlight the molecular and cellular mechanisms that drive the phenotypic plasticity of VaMPs and summarize combinatory strategies for targeting VaMPs in overt metastasis.

Molecular Mechanism of lncRNAs in Regulation of Breast Cancer Metastasis; a Comprehensive Review

Although the number of breast cancer deaths has decreased, and there have been developments in targeted therapies and combination treatments for the management of metastatic illness, metastatic breast cancer is still the second most common cause of cancer-related deaths in U.S. women. Numerous phases and a vast number of proteins and signaling molecules are involved in the invasion-metastasis cascade. The tumor cells penetrate and enter the blood or lymphatic vessels, and travel to distant organs via the lymphatic or blood vessels. Tumor cells enter cell cycle arrest, adhere to capillary beds in the target organ, and then disseminate throughout the organ's parenchyma, proliferating and enhancing angiogenesis. Each of these processes is regulated by changes in the expression of different genes, in which lncRNAs play a role in this regulation. Transcripts that are longer than 200 nucleotides and do not translate into proteins are called RNAs. LncRNA molecules, whose function depends on their unique molecular structure, play significant roles in controlling the expression of genes at various epigenetic levels, transcription, and so on. LncRNAs have essential functions in regulating the expression of genes linked to cell development in healthy and pathological processes, specialization, programmed cell death, cell division, invasion, DNA damage, and spread to other parts of the body. A number of cancer types have been shown to exhibit aberrant expression of lncRNAs. In this review, we describe the general characteristics, potential molecular mechanisms and targeted therapy of lncRNAs and discuss the emerging functions of lncRNAs in breast cancer.

Role of Triple-Negative Breast Cancer-Derived Extracellular Vesicles in Metastasis: Implications for Therapeutics and Biomarker Development

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer with a poor prognosis and high mortality. The chemotherapeutic regimen remains the predominant treatment modality for TNBC in current clinical practice. However, chemotherapy resistance significantly complicates the development of an effective treatment regimen. Furthermore, the immunosuppressive microenvironment of TNBC contributes to enhanced tumour aggressiveness. Consequently, understanding its mechanisms of progression and finding effective therapeutic interventions is crucial. Recent evidence has identified extracellular vesicles (EVs) as key mediators of cell-to-cell communication in TNBC progression and immune regulation. In view of the remarkable ability of EVs to transfer active molecules, such as proteins and nucleic acids, from parental to recipient cells, they are regarded as a promising biomarker and novel drug delivery system. In this review, we provide an overview of how EVs derived from TNBC cells and tumour microenvironment cells play a role in regulating tumour progression. We also discuss the potential of EVs for immune regulation and their application as novel therapeutic strategies and tumour markers in TNBC. The knowledge gained from studying EV-mediated communication in TNBC could lead to the development of targeted therapies and improve patient outcomes.

NFE2-driven neutrophil polarization promotes pancreatic cancer liver metastasis progression

Pancreatic cancer liver metastasis is an important factor leading to dismal prognoses. The details of adaptive immune remodeling in liver metastasis, especially the role of neutrophils, remain elusive. Here, combined single-cell sequencing with spatial transcriptomics results revealed that liver metastases exhibit more aggressive transcriptional characteristics and higher levels of immunosuppression compared with the primary tumor. We identified neutrophils_S100A12 (S100 calcium binding protein A12) cells as the pivotal pro-metastatic cluster, specifically distributed at the invasive front of the metastatic lesions. Mechanistically, our findings indicated that nuclear factor erythroid 2 (NFE2) is a key transcription factor regulating neutrophil phenotypic polarization. Metastatic tumors produce transforming growth factor β to activate the SMAD3 pathway within neutrophils, inducing NFE2-driven polarization. NFE2 promotes the transcription of peptidylarginine deiminase 4 by binding to its promoter, leading to the generation of neutrophil extracellular traps at the invasive front. Collectively, our data demonstrate that NFE2-driven neutrophil polarization is a potential target for anti-metastatic therapy.

Intratumoral microbiome: implications for immune modulation and innovative therapeutic strategies in cancer

Recent advancements have revealed the presence of a microbiome within tumor tissues, underscoring the crucial role of the tumor microbiome in the tumor ecosystem. This review delves into the characteristics of the intratumoral microbiome, underscoring its dual role in modulating immune responses and its potential to both suppress and promote tumor growth. We examine state-of-the-art techniques for detecting and analyzing intratumoral bacteria, with a particular focus on their interactions with the immune system and the resulting implications for cancer prognosis and treatment. By elucidating the intricate crosstalk between the intratumoral microbiome and the host immune system, we aim to uncover novel therapeutic strategies that enhance the efficacy of cancer treatments. Additionally, this review addresses the existing challenges and future prospects within this burgeoning field, advocating for the integration of microbiome research into comprehensive cancer therapy frameworks.

A glucose-enriched lung pre-metastatic niche triggered by matrix stiffness-tuned exosomal miRNAs in hepatocellular carcinoma

Apart from the classic features, it is almost unknown whether there exist other new pathological features during pre-metastatic niche formation in hepatocellular carcinoma (HCC). Our previous works have highlighted the contribution of increased matrix stiffness to lung pre-metastatic niche formation and metastasis in HCC. However, whether increased matrix stiffness influences glucose metabolism and supply of lung pre-metastatic niche remains largely unclear. Here we uncover the underlying mechanism by which matrix stiffness-tuned exosomal miRNAs as the major contributor modulate glucose enrichment during lung pre-metastatic niche formation through decreasing the glucose uptake and consumption of lung fibroblasts and increasing angiogenesis and vascular permeability. Our findings suggest that glucose enrichment, a new characteristic of the lung pre-metastatic niche triggered by matrix stiffness-tuned exosomal miRNAs, is essential for the colonization and survival of metastatic tumor cells, as well as subsequent metastatic foci growth.

Uterine-derived exosomes induce the M2 polarization of macrophages via miR-210-3p/ATP5D to promote endometriosis progression

AIMS

Endometriosis development is associated with peritoneal immune microenvironment abnormality; however, the specific mechanism is uncertain. We aimed to investigate the effects and underlying mechanisms of uterine cavity-derived exosomes on macrophage polarization and endometriosis progression.

MATERIALS AND METHODS

Uterine cavity-derived exosomes, miR-210-3p inhibitor or siATP5D were used to treat macrophages. Then evaluated the polarization of macrophages. By co-culturing of treated macrophages with endometrial stromal cells in vitro and an endometriosis C57BL6 mouse model to assess the role of uterine-derived exosomes and macrophages in the development of endometriosis.

KEY FINDINGS

Uterine cavity-derived exosomes could increase miR-210-3p expression and induce M2 macrophage polarization. Mechanistically, miR-210-3p can restrict ATP5D expression in macrophages, which leads to M2 polarization. In vivo experiments confirmed that macrophages lentivirally transduced with miR-210-3p can significantly decrease the growth and implantation of mouse endometriosis.

SIGNIFICANCE

In summary, our findings suggest that exosomes derived from the uterine cavity may drive macrophages towards M2 and promote endometriosis progression via miR-210-3p/ATP5D.

N, Huang J, Li Y, Zhao G, Liu M. Exosome tropism and various pathways in lung cancer metastasis

Lung cancer, characterized by its high morbidity and mortality rates, has the capability to metastasize to various organs, thereby amplifying its detrimental impact and fatality. The metastasis of lung cancer is a complex biological phenomenon involving numerous physiological transformations. Exosomes, small membranous vesicles enriched with biologically active components, are pivotal in mediating intercellular communication and regulating physiological functions due to their specificity and stability. Extensive research has elucidated the production and functions of exosomes in cancer contexts. Multitude of evidence demonstrates a strong association between lung cancer metastasis and exosomes. Additionally, the concept of the pre-metastatic niche is crucial in the metastatic process facilitated by exosomes. This review emphasizes the role of exosomes in mediating lung cancer metastasis and their impact on the disease's development and the progression to other tissues. Furthermore, it explores the potential of exosomes as biomarkers for lung cancer metastasis, offering significant insights for future clinical advancements.

The Tight Relationship Between the Tumoral Microenvironment and Radium-223

Radium-223 (223Ra) was the first radioactive isotope approved for treating castration-resistant prostate cancer (CRPC) with symptomatic bone metastases without visceral metastatic disease. To better understand the action of 223Ra, its role in the tumor microenvironment represents a crucial aspect. A literature search was conducted using the PubMed/MEDLINE database and studies regarding the relationship between 223Ra and the tumoral microenvironment were considered. The tumoral microenvironment is a complex setting in which complex interactions between cells and molecules occur. Radium-223, as an alpha-emitter, induces double-stranded DNA breaks; to potentiate this effect, it could be used in patients with genetic instability but also in combination with therapies which inhibit DNA repair, modulate the immune response, or control tumor growth. In conclusion, a few studies have taken into consideration the tumoral microenvironment in association with 223Ra. However, its understanding is a priority to better comprehend how to effectively exploit 223Ra and its action mechanism.