Crosstalk of renal cell carcinoma cells and tumor-associated macrophages aggravates tumor progression by modulating muscleblind-like protein 2/B-cell lymphoma 2/beclin 1-mediated autophagy

Functions of the Muscleblind-like protein family and their role in disease

Conserved proteins are characterized by their functions remaining nearly constant throughout evolutionary history, both vertically through time and horizontally across species. In this review, we focus on a class of conserved proteins known as the Muscleblind-like (MBNL) family. As RNA-binding proteins, MBNL family members interact with pre-mRNAs through evolutionarily conserved tandem zinc finger domains and play critical roles in various RNA metabolic processes, including alternative splicing, mRNA stability, trafficking, regulation of subcellular localization, and alternative polyadenylation. Dysregulation of MBNL proteins can lead to severe consequences. Initially, research primarily associated MBNL proteins with myotonic dystrophy. However, recent studies have revealed their involvement in a broad spectrum of physiological and pathological processes, such as embryonic tissue differentiation and circulatory disorders. Furthermore, the emerging role of MBNL proteins in cancer sheds light on a novel aspect of these evolutionarily ancient proteins. This review provides a comprehensive overview of the MBNL family, emphasizing its structure, the mechanisms underlying its biological functions, and its roles in various diseases.Subject terms: Muscleblind-like-like protein, RNA-binding proteins, Alternative splicing, Tumor, Myotonic dystrophy.

Targeting autophagy in urological system cancers: From underlying mechanisms to therapeutic implications

The urological system, including kidneys, ureters, bladder, urethra and prostate is known to be vital for blood filtration, waste elimination and electrolyte balance. Notably, urological system cancers represent a significant portion of global cancer diagnoses and mortalities. The current therapeutic strategies for early-stage cancer primarily involve resection surgery, which significantly affects the quality of life of patients, whereas advanced-stage cancer often relies on less effective chemo- or radiotherapy. Recently, accumulating evidence has revealed that autophagy, a crucial process in which excess organelles or inclusions within cells are removed to maintain cell homeostasis, has numerous links to urological system cancers. In this review, we focus on summarizing the underlying two-sided mechanisms of autophagy in urological system cancers. We also review the current clinical drugs targeting autophagy, which demonstrate significant potential in improving treatment outcomes for urological system cancers. In addition, we provide an overview of the research status of novel small molecule compounds targeting autophagy that are in the preclinical stages of investigation. Furthermore, drug combinations based on autophagy modulation strategies in urological system cancers are systematically summarized and discussed. These findings provide comprehensive new insight for the future discovery of more autophagy-related drug candidates.

Unveiling the contribution of tumor-associated macrophages in driving epithelial-mesenchymal transition: a review of mechanisms and therapeutic Strategies

Tumor-associated macrophages (TAMs), fundamental constituents of the tumor microenvironment (TME), significantly influence cancer development, primarily by promoting epithelial-mesenchymal transition (EMT). EMT endows cancer cells with increased motility, invasiveness, and resistance to therapies, marking a pivotal juncture in cancer progression. The review begins with a detailed exposition on the origins of TAMs and their functional heterogeneity, providing a foundational understanding of TAM characteristics. Next, it delves into the specific molecular mechanisms through which TAMs induce EMT, including cytokines, chemokines and stromal cross-talking. Following this, the review explores TAM-induced EMT features in select cancer types with notable EMT characteristics, highlighting recent insights and the impact of TAMs on cancer progression. Finally, the review concludes with a discussion of potential therapeutic targets and strategies aimed at mitigating TAM infiltration and disrupting the EMT signaling network, thereby underscoring the potential of emerging treatments to combat TAM-mediated EMT in cancer. This comprehensive analysis reaffirms the necessity for continued exploration into TAMs' regulatory roles within cancer biology to refine therapeutic approaches and improve patient outcomes.

CircPRELID2 functions as a promoter of renal cell carcinoma through the miR-22-3p/ETV1 cascade

BACKGROUND

Emerging evidence has indicated that a number of circular RNAs (circRNAs) participate in renal cell carcinoma (RCC) carcinogenesis. Nevertheless, the activity and molecular process of circPRELID2 (hsa_circ_0006528) in RCC progression remain unknown.

METHODS

CircPRELID2, miR-22-3p and ETS variant 1 (ETV1) levels were gauged by qRT-PCR. Effect of the circPRELID2/miR-22-3p/ETV1 axis was evaluated by detecting cell growth, motility, and invasion. Immunoblotting assessed related protein levels. The relationships of circPRELID2/miR-22-3p and miR-22-3p/ETV1 were confirmed by RNA immunoprecipitation (RIP), luciferase reporter or RNA pull-down assay.

RESULTS

CircPRELID2 was up-regulated in RCC. CircPRELID2 silencing suppressed RCC cell growth, motility and invasion. Moreover, circPRELID2 silencing weakened M2-type macrophage polarization in THP1-induced macrophage cells. CircPRELID2 sequestered miR-22-3p, and circPRELID2 increased ETV1 expression through miR-22-3p. Moreover, the inhibitory impact of circPRELID2 silencing on RCC cell malignant behaviors was mediated by the miR-22-3p/ETV1 axis. Furthermore, circPRELID2 knockdown in vivo hampered growth of xenograft tumors.

CONCLUSION

Our study demonstrates that circPRELID2 silencing can mitigate RCC malignant development through the circPRELID2/miR-22-3p/ETV1 axis, highlighting new therapeutic targets for RCC treatment.

Crosstalk between cancer cells and macrophages promotes OSCC cell migration and invasion through a CXCL1/EGF positive feedback loop

BACKGROUND

C-X-C motif chemokine ligand 1 (CXCL1) and epithelial growth factor (EGF) are highly secreted by oral squamous cell carcinoma (OSCC) cells and tumor-associated macrophages, respectively. Recent studies have shown that there is intricate "cross-talk" between OSCC cells and macrophages. However, the underlying mechanisms are still poorly elucidated.

METHODS

The expression of CXCL1 was detected by immunohistochemistry in OSCC clinical samples. CXCL1 levels were evaluated by RT‒PCR and ELISA in an OSCC cell line and a normal epithelial cell line. The expression of EGF was determined by RT‒PCR and ELISA. The effect of EGF on the proliferation of OSCC cells was evaluated by CCK-8 and colony formation assays. The effect of EGF on the migration and invasion ability and epithelial-mesenchymal transition (EMT) of OSCC cells was determined by wound healing, Transwell, RT‒PCR, Western blot and immunofluorescence assays. The polarization of macrophages was evaluated by RT‒PCR and flow cytometry. Western blotting was used to study the molecular mechanism in OSCC.

RESULTS

The expression of C-X-C motif chemokine ligand 1 (CXCL1) was higher in the OSCC cell line (Cal27) than in immortalized human keratinocytes (Hacat cells). CXCL1 derived from Cal27 cells upregulates the expression of epithelial growth factor (EGF) in macrophages. Paracrine stimulation mediated by EGF further facilitates the epithelial-mesenchymal transition (EMT) of Cal27 cells and initiates the upregulation of CXCL1 in a positive feedback-manner. Mechanistically, EGF signaling-induced OSCC cell invasion and migration can be ascribed to the activation of NF-κB signaling mediated by the epithelial growth factor receptor (EGFR), as determined by western blotting.

CONCLUSIONS

OSCC cell-derived CXCL1 can stimulate the M2 polarization of macrophages and the secretion of EGF. Moreover, EGF significantly activates NF-κB signaling and promotes the migration and invasion of OSCC cells in a paracrine manner. A positive feedback loop between OSCC cells and macrophages was formed, contributing to the promotion of OSCC progression.

A novel antagonist of the CCL5/CCR5 axis suppresses the tumor growth and metastasis of triple-negative breast cancer by CCR5-YAP1 regulation

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer (BC) with a high mortality rate, and few effective therapeutic strategies are available. CCL5/CCR5 is an appealing immunotherapeutic target for TNBC. However, its signaling mechanism is poorly understood and its direct antagonists have not been reported. Here, we developed a high-throughput screening (HTS) assay for discovering its antagonists. Verteporfin was identified as a more selective and potent antagonist than the known CCR5 antagonist maraviroc. Without photodynamic therapy, verteporfin demonstrated significant inhibition on TNBC tumor growth through immune regulation, remarkable suppression of lung metastasis by cell-intrinsic mechanism, and a significant extension of overall survival in vivo. Mechanistically, CCR5 was found to be essential for expression of the key hippo effector YAP1. It promoted YAP1 transcription via HIF-1α and exerted further control over the migration of CD8+ T, NK, and MDSC immune cells through chemokines CXCL16 and CXCL8 which were identified from RNA-seq. Moreover, the CCR5-YAP1 axis played a vital role in promoting metastasis by modulating β-catenin and core epithelial-mesenchymal transition transcription factors ZEB1 and ZEB2. It is noteworthy that the regulatory relationship between CCR5 and YAP1 was observed across various BC subtypes, TNBC patients, and showed potential relevance in fifteen additional cancer types. Overall, this study introduced an easy-to-use HTS assay that streamlines the discovery of CCL5/CCR5 axis antagonists. Verteporfin was identified as a specific molecular probe of this axis with great potentials as a therapeutic agent for treating sixteen malignant diseases characterized by heightened CCR5 and YAP1 levels.

Radiomics Correlation to CD68+ Tumor-Associated Macrophages in Clear Cell Renal Cell Carcinoma

INTRODUCTION

Renal cell carcinoma (RCC) is the ninth most common cancer worldwide, with clear cell RCC (ccRCC) being the most frequent histological subtype. The tumor immune microenvironment (TIME) of ccRCC is an important factor to guide treatment, but current assessments are tissue-based, which can be time-consuming and resource-intensive. In this study, we used radiomics extracted from clinically performed computed tomography (CT) as a noninvasive surrogate for CD68 tumor-associated macrophages (TAMs), a significant component of ccRCC TIME.

METHODS

TAM population was measured by CD68+/PanCK+ ratio and tumor-TAM clustering was measured by normalized K function calculated from multiplex immunofluorescence (mIF). A total of 1,076 regions on mIF slides from 78 patients were included. Radiomic features were extracted from multiphase CT of the ccRCC tumor. Statistical machine learning models, including random forest, Adaptive Boosting, and ElasticNet, were used to predict TAM population and tumor-TAM clustering.

RESULTS

The best models achieved an area under the ROC curve of 0.81 (95% CI: [0.69, 0.92]) for TAM population and 0.77 (95% CI: [0.66, 0.88]) for tumor-TAM clustering, respectively.

CONCLUSION

Our study demonstrates the potential of using CT radiomics-derived imaging markers as a surrogate for assessment of TAM in ccRCC for real-time treatment response monitoring and patient selection for targeted therapies and immunotherapies.