Downregulation of miR-100-5p in cancer-associated fibroblast-derived exosomes facilitates lymphangiogenesis in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC), an aggressive gastrointestinal tumor, often has high early lymphatic metastatic potential. Cancer-associated fibroblasts (CAFs) are primary components in tumor microenvironment (TME), and the impact of CAFs and its derived exosomes on lymphangiogenesis remains elusive. MATERIALS AND METHODS: CAFs and the microlymphatic vessel density (MLVD) in ESCC was examined. Exosomes were extracted from primary normal fibroblast (NFs) and CAFs. Subsequently, tumor-associated lymphatic endothelial cells (TLECs) were treated with these exosomes, and the effect on their biological behavior was examined. miR-100-5p was selected as the target miRNA, and its effect on TLECs was examined. The target of miR-100-5p was predicted and confirmed. Subsequently, IGF1R, PI3K, AKT, and p-AKT expression in TLECs and tumors treated with exosomes and miR-100-5p were examined. RESULTS: A large number of CAFs and microlymphatic vessels were present in ESCC, leading to a poor prognosis. CAF-derived exosomes promoted proliferation, migration, invasion, and tube formation in TLECs. Further, they also enhanced lymphangiogenesis in ESCC xenografts. miR-100-5p levels were significantly lower in CAF-derived exosomes than in NF-derived exosomes. miR-100-5p inhibited proliferation, migration, invasion, and tube formation in TLECs. Further, miR-100-5p inhibited lymphangiogenesis in ESCC xenografts. Mechanistic studies revealed that this inhibition was mediated by the miR-100-5p-induced inhibition of IGF1R/PI3K/AKT axis. CONCLUSION: Taken together, our study demonstrates that CAF-derived exosomes with decreased miR-100-5p levels exhibit pro-lymphangiogenesis capacity, suggesting a possibility of targeting IGF1R/PI3K/AKT axis as a strategy to inhibit lymphatic metastasis in ESCC.

Similarities between wound re-epithelialization and Metastasis in ESCC and the crucial involvement of macrophages: A review.

In cancer, tumor-associated macrophages (TAMs) possess crucial functions in facilitating epithelial-mesenchymal transition (EMT). EMT is a crucial process in tumor metastasis. Tumor metastasis is one of the hallmarks of cancer and leads to patient mortality. Cancer cells often find ways to evade being detected and attacked by the immune system. This is achieved by cross-talk between cancer cells and the altered microenvironment. The accumulation of tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) creates an immunosuppressive and tumor-supportive environment. Circulating monocytes and macrophages which are recruited into tumors are defined as tumor-associated macrophages once in the TME. Based on the activated stimuli and function, macrophages can be divided into M1 macrophages and M2 macrophages. M1 macrophages, also known as classically activated macrophages, exhibit pro-inflammatory and antitumor activities. M2 macrophages, also known as alternatively activated macrophages, exhibit anti-inflammatory, pro-tumorigenic, and wound healing activities. TAMs are considered to be of the M2 phenotype. The TME polarizes recruited macrophages into M2 macrophages as they provide an immunosuppressive pro-tumoral environment. Accumulating studies show that the presence of TAMs in esophageal squamous cell carcinoma (ESCC) leads to tumor progression. In this review, we discuss how EMT can be used by TAMs to cause tumor migration and metastasis in ESCC. We also discuss the potential therapies targeting TAMs.

Clinical features and prognostic significance of tumor involved with subventricular zone in pediatric glioblastoma: a 10-year experience in a single hospital.

PURPOSE: Tumors involved with subventricular zone (SVZ) predicted an adverse prognosis had been well proved in adult glioblastoma (GBM). However, we still know less about its impact on children due to the rarity of pediatric glioblastoma (pGBM). We performed this retrospective study to better understand the clinical and prognostic features of pGBM involved with SVZ. METHODS: Fifty-two patients diagnosed with pGBM at our center between January 2011 and January 2021 were selected for review to demonstrate the characteristics of tumor contacting SVZ. Thirty patients who underwent concurrent chemoradiotherapy and adjuvant chemotherapy postoperatively were selected for survival analysis. RESULTS: Of all the 52 patients, 21 were found to contact SVZ and 31 were not. The median PFS and OS in SVZ + patients were 5.2 and 8.9 months, respectively, whereas median PFS and OS were 11.9 and 17.9 months, respectively, in SVZ - patients. Multivariate analysis showed that involvement of SVZ was an independent prognostic factor for OS while focality at diagnosis was an independent prognostic factor for PFS. Tumors contacted with SVZ tend to have larger volumes, lower incidence of epilepsy, and lower total resect rate and they were more likely to originate from midline location. Age at diagnosis; gender; adjuvant therapy; focality at diagnosis; focality at relapse; mutational status of H3K27M, MGMT, IDH1, and IDH2; and expression of P53 and ATRX protein failed to characterize SVZ + patients. CONCLUSION: Involvement of SVZ predicted worse OS in pGBM and it had some distinct clinical features in comparison with those that did not contact with SVZ. Multifocal tumor at diagnosis was related to a shorter PFS. We should make a further step to clarify its molecular features.

Exosomal miR-301a-3p from esophageal squamous cell carcinoma cells promotes angiogenesis by inducing M2 polarization of macrophages via the PTEN/PI3K/AKT signaling pathway.

BACKGROUND: Growing evidence has indicated that tumor-associated macrophages (TAMs) promote tumor angiogenesis. However, the mechanisms underlying the pro-angiogenic switch of TAMs remains unclear. Here, we examined how exosomal miR-301a-3p secreted by esophageal squamous cell carcinoma (ESCC) cells triggers the pro-angiogenic switch of TAMs. METHODS: We quantified miR-301a-3p levels in ESCC tumors using qRT-PCR. Macrophage phenotypes were identified using flow cytometry and qRT-PCR. The pro-angiogenic ability of TAMs was measured using the CCK-8 assay, scratch assay, Transwell migration and invasion assay, and tube formation assay. The mechanism by which exosomal miR-301a-3p secreted by ESCC cells triggers the pro-angiogenic switch of TAMs was elucidated using western blots, qRT-PCR, and a dual-luciferase reporter assay. RESULTS: We observed anomalous miR-301a-3p overexpression in ESCC tumor tissues and cell lines. Then, we verified that ESCC-derived exosomes promoted angiogenesis by inducing macrophage polarization into M2 type, and exosomal miR-301a-3p secreted by ESCC cells was responsible for this effect. Finally, we discovered that exosomal miR-301a-3p promoted M2 macrophage polarization via the inhibition of PTEN and activation of the PI3K/AKT signaling pathway, subsequently promoting angiogenesis via the secretion of VEGFA and MMP9. CONCLUSION: The pro-angiogenic switch of TAMs is triggered by exosomal miR-301a-3p secreted from ESCC cells via the PTEN/PI3K/AKT signaling pathway. Although tumor angiogenesis can be regulated by a wide range of factors, exosomal miR-301a-3p could hold promise as a novel anti-angiogenesis target for ESCC treatment.

Exosomes-derived miR-154-5p attenuates esophageal squamous cell carcinoma progression and angiogenesis by targeting kinesin family member 14.

Exosomes participate in the progression and angiogenesis of esophageal squamous cell carcinoma (ESCC). This study aimed to explore the effect and mechanism of exosomes-derived miR-154-5p on the progression and angiogenesis of ESCC. The exosomes with the diameter of 40-270 nm were successfully isolated from ESCC cells by ultracentrifugation. They were then assessed by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), and Western blotting. Kinesin family member 14 (KIF14) was upregulated, while miR-154-5p was downregulated in ESCC as examined by Quantitative Real-time PCR (qRT-PCR). Exosomes-derived miR-154-5p from ESCC cells was found to attenuate the cellular migration, invasion, and angiogenesis of ESCC using Cell Counting Kit-8 (CCK-8), wound healing assay, transwell migration assay, and tumor formation assays. Moreover, KIF14 was proven to be a direct downstream target gene of miR-154-5p in ESCC cells using luciferase assay. In conclusion, our study identified that exosomes-derived miR-154-5p attenuates ESCC progression and angiogenesis by targeting KIF14 in vitro, which might provide a novel approach for the diagnosis and treatment of ESCC.

Relationship Between PTEN and Angiogenesis of Esophageal Squamous Cell Carcinoma and the Underlying Mechanism.

Esophageal squamous cell carcinoma (ESCC) has high morbidity and mortality rates owing to its ability to infiltrate and metastasize. Microvessels formed in early-stage ESCC promote metastasis. Phosphatase and tensin homolog (PTEN) mediates macrophage polarization, but its effect and mechanism on early ESCC angiogenesis are unclear. To explore the molecular mechanism underlying early ESCC metastasis through blood vessels, we investigated the relationship between PTEN/phosphoinositide 3-kinase (PI3K)/p-AKT protein levels, number of infiltrated macrophages, and angiogenesis in ESCC and ESCC-adjacent normal esophageal mucosa tissues from 49 patients. Additionally, PTEN was overexpressed or silenced in the esophageal cancer cell line EC9706, and its supernatant served as conditioning medium for M1 tumor-associated macrophages (TAMs). The culture medium of macrophages served as conditioning medium for esophageal tumor-associated vascular endothelial cells (TECs) to study the biological behavior of PTEN-plasmid, PTEN-siRNA, and control TECs. We found that M1 TAM infiltration in ESCC tissues was low, whereas M2 TAM infiltration was high. Microvessel density was large, PTEN was down-regulated, and the PI3K/AKT pathway was activated in ESCC specimens. These parameters significantly related to the depth of tumor invasion, lymph node metastasis, and pathological staging of ESCC. Silencing of PTEN in EC9706 cells significantly activated the PI3K/AKT signaling pathway in macrophages, promoting M1-to-M2 TAM polarization and enhancing TECs' ability to proliferate, migrate, invade, form tubes, and secrete vascular endothelial growth factor. We believe that PTEN silencing in esophageal cancer cells activates the PI3K/AKT signaling pathway in macrophages via the tumor microenvironment, induces M2 TAM polarization, and enhances the malignant behavior of TECs, thereby promoting ESCC angiogenesis. Our findings lay an empirical foundation for the development of novel diagnostic and therapeutic strategies for ESCC.

Tumor-associated macrophages modulate angiogenesis and tumor growth in a xenograft mouse model of multiple myeloma.

Tumor-associated macrophages (TAMs) are closely associated with poor multiple myeloma (MM) prognosis. Therefore, in-depth understanding of the mechanism by which TAM supports MM progression may lead to its effective treatment. We used the MM nude mouse subcutaneous xenograft model to evaluate the efficacy of the macrophage-depleting agent clodronate liposome (Clo) against MM and elucidate the mode of action of this therapy. At the same time, observe whether the elimination of TAM in vivo while silencing the expression of VEGFA has the same effect as in vitro experiments. We also used Clo to eliminate macrophages and reinjected M1 or M2 TAM through mouse tail veins to investigate the effects of various macrophage subtypes on MM xenograft tumor growth. We applied qRT-PCR, immunohistochemistry, and enzyme-linked immunosorbent assay to quantify VEGFA, CD31, and CD163 expression in tumor tissues and sera. Removal of TAMs from the tumor microenvironment impeded tumor growth. The combination of Clo plus VEGFA siRNA had a stronger inhibitory effect on tumor growth than Clo alone, and M2 and M1 macrophages promoted and inhibited tumor growth, respectively. Macrophage depletion combined with cytokine blocking is a promising MM treatment. Targeted M2 macrophage elimination together with cytokine block may be more effective at inhibiting MM growth than either treatment alone. The results of the present study lay an empirical foundation for the development of novel therapeutic strategies for MM.

Synergistic effects of multiple myeloma cells and tumor-associated macrophages on vascular endothelial cells in vitro.

Angiogenesis is a prerequisite for multiple myeloma development. Tumor cells can stimulate angiogenesis by secreting vascular endothelial growth factor A (VEGFA), but we previously reported that tumor angiogenesis was not significantly reduced when VEGFA expression was inhibited in myeloma cells. Tumor-associated macrophages (TAMs) are important components of the tumor microenvironment and have been reported to be involved in the regulation of angiogenesis. In this study, we performed in vitro macrophage coculture studies and studies with RPMI 8226 and TAMs cell-conditioned media to explore their effects on the proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs). Our results showed that M2 macrophages and RPMI 8226 cells could synergistically promote HUVEC proliferation, migration, and tube formation, and that VEGFA depletion in both cell types suppressed HUVEC tube formation ability. Conversely, M1 macrophages inhibited the tube formation in HUVECs. Mechanistically, M2 macrophage secretion of VEGFA may affect vascular endothelial growth factor receptor 1 signaling to regulate angiogenesis. In summary, our results suggest that macrophage clearance or inducing of transformation of M2 macrophages into M1 macrophages are potential treatment strategies for multiple myeloma.