The role of cancer-associated fibroblasts in bladder cancer progression.

Cancer-associated fibroblasts (CAFs) are key stromal cells in the tumor microenvironment (TME) that critically contribute to cancer initiation and progression. In bladder cancer (BCa), there is emerging evidence that BCa CAFs are actively involved in cancer cell proliferation, invasion, metastasis, and chemotherapy resistance. This review outlines the present knowledge of BCa CAFs, with a particular emphasis on their origin and function in BCa progression, and provides further insights into their clinical application.

Cancer-associated fibroblast-derived PAI-1 promotes lymphatic metastasis via the induction of EndoMT in lymphatic endothelial cells.

BACKGROUND: Endothelial-mesenchymal transition (EndoMT) is an emerging adaptive process that modulates lymphatic endothelial function to drive aberrant lymphatic vascularization in the tumour microenvironment (TME); however, the molecular determinants that govern the functional role of EndoMT remain unclear. Here, we show that cancer-associated fibroblast (CAF)-derived PAI-1 promoted the EndoMT of lymphatic endothelial cells (LECs) in cervical squamous cell carcinoma (CSCC). METHODS: Immunofluorescent staining of α-SMA, LYVE-1 and DAPI were examined in primary tumour samples obtained from 57 CSCC patients. Assessment of cytokines secreted by CAFs and normal fibroblasts (NFs) was performed using human cytokine antibody arrays. The phenotype of EndoMT in lymphatic endothelial cells (LECs), gene expression levels, protein secretion and activity of signaling pathways were measured by real-time RT-PCR, ELISA or western blotting. The function of lymphatic endothelial monolayers was examined by transwell, tube formation assay, transendothelial migration assay in vitro. Lymphatic metastasis was measured using popliteal lymph node metastasis model. Furthermore, association between PAI-1 expression and EndoMT in CSCC was analyzed by immunohistochemistry. The Cancer Genome Atlas (TCGA) databases was used to assess the association of PAI-1 with survival rate in CSCC. RESULTS: CAF-derived PAI-1 promoted the EndoMT of LECs in CSCC. LECs undergoing EndoMT could initiate tumour neolymphangiogenesis that facilitated cancer cell intravasation/extravasation, which in turn promoted lymphatic metastasis in CSCC. Mechanistically, PAI-1 activated the AKT/ERK1/2 pathways by directly interacting with low-density lipoprotein receptor-related protein (LRP1), thereby leading to elevated EndoMT activity in LECs. Blockade of PAI-1 or inhibition of LRP1/AKT/ERK1/2 abrogated EndoMT and consequently attenuated CAF-induced tumour neolymphangiogenesis. Furthermore, clinical data revealed that increased PAI-1 levels positively correlated with EndoMT activity and poor prognosis in CSCC patients. CONCLUSION: Our data indicate that CAF-derived PAI-1 acts as an important neolymphangiogenesis-initiating molecular during CSCC progression through modulating the EndoMT of LECs, resulting in promotion of metastasis ability in primary site. PAI-1 could serve as an effective prognostic biomarker and therapeutic target for CSCC metastasis.

Cancer-Associated Fibroblast Heterogeneity: A Factor That Cannot Be Ignored in Immune Microenvironment Remodeling.

Cancer-associated fibroblasts (CAFs) are important, highly heterogeneous components of the tumor extracellular matrix that have different origins and express a diverse set of biomarkers. Different subtypes of CAFs participate in the immune regulation of the tumor microenvironment (TME). In addition to their role in supporting stromal cells, CAFs have multiple immunosuppressive functions, via membrane and secretory patterns, against anti-tumor immunity. The inhibition of CAFs function and anti-TME therapy targeting CAFs provides new adjuvant means for immunotherapy. In this review, we outline the emerging understanding of CAFs with a particular emphasis on their origin and heterogeneity, different mechanisms of their regulation, as well as their direct or indirect effect on immune cells that leads to immunosuppression.

Tumor-secreted exosomal Wnt2B activates fibroblasts to promote cervical cancer progression.

The activation of stromal fibroblasts into cancer-associated fibroblasts (CAFs) has been suggested to promote primary tumor growth and progression; however, the mechanisms underlying the crosstalk between tumors and fibroblasts that drives stromal heterogeneity remain unknown. Here, we show that high Wnt2B levels were positively correlated with the number of CAFs in cervical cancer (CC). More importantly, Wnt2B was characteristically enriched in CC cell-secreted exosomes and transferred into fibroblasts to promote fibroblast activation via Wnt/ß-catenin signaling, and inhibiting exosomal release or the Wnt/ß-catenin signaling pathway diminished the activation induced by exosomal Wnt2B. Moreover, circulating exosomal Wnt2B also promoted CAF conversion in vitro and its expression was significantly higher in CC patients. In conclusion, our findings indicate that CC cell-derived Wnt2B can induce the activation of fibroblasts into CAFs, mainly via exosome-dependent secretion, thus providing directions for the development of diagnostic and therapeutic targets for CC progression.

A novel lymphatic pattern promotes metastasis of cervical cancer in a hypoxic tumour-associated macrophage-dependent manner.

Lymphatic remodelling in the hypoxic tumour microenvironment (TME) is critically involved in the metastasis of cervical squamous cell carcinoma (CSCC); however, its underlying mechanisms remain unclear. Here, we uncovered a novel lymphatic pattern in the hypoxic TME, wherein lymphatic vessels (LVs) are encapsulated by tumour-associated macrophages (TAMs) to form an interconnected network. We describe these aggregates as LVEM (LVs encapsulated by TAMs) considering their advantageous metastatic capacity and active involvement in early lymph node metastasis (LNM). Mechanistic investigations revealed that interleukin-10 (IL-10) derived from hypoxic TAMs adjacent to LVs was a prerequisite for lymphangiogenesis and LVEM formation through its induction of Sp1 upregulation in lymphatic endothelial cells (LECs). Interestingly, Sp1high LECs promoted the transactivation of C-C motif chemokine ligand 1 (CCL1) to facilitate TAM and tumour cell recruitment, thereby forming a positive feedback loop to strengthen the LVEM formation. Knockdown of Sp1 or blockage of CCL1 abrogated LVEM and consequently attenuated LNM. Notably, CSCCnon-LNM is largely devoid of hypoxic TAMs and the resultant LVEM, which might explain its metastatic delay. These findings identify a novel and efficient metastasis-promoting lymphatic pattern in the hypoxic TME, which might provide new targets for anti-metastasis therapy and prognostic assessment.

Periostin+ cancer-associated fibroblasts promote lymph node metastasis by impairing the lymphatic endothelial barriers in cervical squamous cell carcinoma.

Lymph node metastasis (LNM), a critical prognostic determinant in cancer patients, is critically influenced by the presence of numerous heterogeneous cancer-associated fibroblasts (CAFs) in the tumor microenvironment. However, the phenotypes and characteristics of the various pro-metastatic CAF subsets in cervical squamous cell carcinoma (CSCC) remain unknown. Here, we describe a CAF subpopulation with elevated periostin expression (periostin+ CAFs), located in the primary tumor sites and metastatic lymph nodes, that positively correlated with LNM and poor survival in CSCC patients. Mechanistically, periostin+ CAFs impaired lymphatic endothelial barriers by activating the integrin-FAK/Src-VE-cadherin signaling pathway in lymphatic endothelial cells and consequently enhanced metastatic dissemination. In contrast, inhibition of the FAK/Src signaling pathway alleviated periostin-induced lymphatic endothelial barrier dysfunction and its related effects. Notably, periostin- CAFs were incapable of impairing endothelial barrier integrity, which may explain the occurrence of CAF-enriched cases without LNM. In conclusion, we identified a specific periostin+ CAF subset that promotes LNM in CSCC, mainly by impairing the lymphatic endothelial barriers, thus providing the basis for potential stromal fibroblast-targeted interventions that block CAF-dependent metastasis.

Hypoxia-induced ZEB1 promotes cervical cancer progression via CCL8-dependent tumour-associated macrophage recruitment.

The accumulation of tumour-associated macrophages (TAMs) in the hypoxic tumour microenvironment (TME) is associated with malignant progression in cancer. However, the mechanisms by which the hypoxic TME facilitates TAM infiltration are not fully understood. This study showed that high ZEB1 expression in hypoxic cervical cancer cell islets was positively correlated with CD163+ TAM accumulation. ZEB1 in hypoxic cancer cells promoted the migration of TAMs in vitro and altered the expression of multiple chemokines, especially CCL8. Mechanistically, hypoxia-induced ZEB1 activated the transcription of CCL8, which attracted macrophages via the CCR2-NF-κB pathway. Furthermore, ZEB1 and CCL8 were independent prognostic factors in cervical cancer patients based on The Cancer Genome Atlas (TCGA) data analysis. In conclusion, hypoxia-induced ZEB1 exerts unexpected functions in cancer progression by fostering a prometastatic environment through increased CCL8 secretion and TAM recruitment; thus, ZEB1 may serve as a candidate biomarker of tumour progression and provide a potential target for disrupting hypoxia-mediated TME remodelling.

Cancer-derived exosomal miR-221-3p promotes angiogenesis by targeting THBS2 in cervical squamous cell carcinoma.

AIMS: Recently, cancer-derived exosomes were shown to have pro-metastasis function in cancer, but the mechanism remains unclear. Angiogenesis is essential for tumor progression and is a great promising therapeutic target for advanced cervical cancer. Here, we investigated the role of cervical cancer cell-secreted exosomal miR-221-3p in tumor angiogenesis. METHODS AND RESULTS: miR-221-3p was found to be closely correlated with microvascular density in cervical squamous cell carcinoma (CSCC) by evaluating the microvascular density with immunohistochemistry and miR-221-3p expression with in situ hybridization in clinical specimens. Using the groups of CSCC cell lines (SiHa and C33A) with miR-221-3p overexpression and silencing, the CSCC exosomes were characterized by electron microscopy, western blotting, and fluorescence microscopy. The enrichment of miR-221-3p in CSCC exosomes and its transfer into human umbilical vein endothelial cells (HUVECs) were confirmed by qRT-PCR. CSCC exosomal miR-221-3p promoted angiogenesis in vitro in Matrigel tube formation assay, spheroid sprouting assay, migration assay, and wound healing assay. Then, exosome intratumoral injection indicated that CSCC exosomal miR-221-3p promoted tumor growth in vivo. Thrombospondin-2 (THBS2) was bioinformatically predicted to be a direct target of miR-221-3p, and this was verified by using the in vitro and in vivo experiments described above. Additionally, overexpression of THBS2 in HUVECs rescued the angiogenic function of miR-221-3p. CONCLUSIONS: Our results suggest that CSCC exosomes transport miR-221-3p from cancer cells to vessel endothelial cells and promote angiogenesis by downregulating THBS2. Therefore, CSCC-derived exosomal miR-221-3p could be a possible novel diagnostic biomarker and therapeutic target for CSCC progression.

The role of the hypoxia-Nrp-1 axis in the activation of M2-like tumor-associated macrophages in the tumor microenvironment of cervical cancer.

To explore the mechanisms through which hypoxic tumor microenvironment (TME) modulates the transition of tumor-associated macrophages (TAMs). The migration ability of RAW264.7 macrophages was determined by transwell assay. Flow cytometric, western blot and immunofluorescence analyses of CD206 further validated the M2 polarization of macrophages. Immunofluorescence, western blot and qRT-PCR were performed to detect the expression of neuropilin-1 (Nrp-1) and carbonic anhydrase IX (CAIX). An intermittent hypobaric hypoxia (IH) animal model was established to evaluate the role of hypoxia in activating M2-like TAMs in vivo. We also used immunohistochemistry to analyze the association between CAIX, CD163+ macrophages and Nrp-1 in a series of 72 human cervical cancer specimens. We found that the hypoxic cervical TME educated the recruited macrophages to transform into the M2 phenotype. Nrp-1 expression was significantly increased in hypoxia-primed cervical cancer cells. Blocking Nrp-1 expression prevented hypoxic cells from recruiting and polarizing macrophages towards the M2 phenotype. Hypoxia exposure significantly increased the expression of Nrp-1 as well as the infiltration of macrophages in vivo. Consistently, immunochemical staining in serial tissue sections of cervical cancer revealed upregulated levels of Nrp-1 in CAIX-positive hypoxic regions along with a concurrent significant elevation of M2 macrophages. Nrp-1 and M2-like TAMs were related to the malignant properties of cervical cancer, such as the FIGO stage and lymph node metastasis. Nrp-1 plays critical roles in hypoxic TME-induced activation and pro-tumoral effects of TAMs in cervical cancer. Interfering with Nrp-1 may be a potential therapeutic strategy in treating cervical cancer.

MicroRNA-221-3p, a TWIST2 target, promotes cervical cancer metastasis by directly targeting THBS2.

MicroRNAs have implicated in the relapse and metastasis of cervical cancer, which is the leading cause of cervical cancer-related mortality. However, the underlying molecular mechanisms need further elucidation. Our present study revealed that miR-221-3p is transcriptionally promoted in metastatic cervical cancer tissues compared with non-metastatic cervical cancer tissues. Forced overexpression of miR-221-3p facilitated EMT and promoted cell migration and invasion in vitro and lymphatic metastasis in vivo. Twist homolog 2 (TWIST2) was found to be a key transcription factor binding to the promoter of miR-221-3p. Inhibitors of miR-221-3p drastically reduced the induction of EMT and decreased cell migration and invasion mediated by TWIST2. By combined computational and experimental approaches, THBS2 was recognized to be an important downstream target gene of miR-221-3p. In cervical cancer tissues, especially with lymphatic metastasis, miR-221-3p and TWIST2 were increased and THBS2 was decreased, suggesting that TWIST2 induces miR-221-3p expression and consequently suppresses its direct target THBS2 in lymphatic metastasis CC. Our findings uncover a mechanistic role for miR-221-3p in lymph node metastasis, suggesting that miR-221-3p is upregulated by the transcription factor TWIST2 and downregulates its target THBS2, which may potentially promote lymph node metastasis in cervical cancer.

Clinical Significance of CD163+ and CD68+ Tumor-associated Macrophages in High-risk HPV-related Cervical Cancer.

Objective. To explore the influence of M2-polarized tumor-associated macrophages (TAMs) on high-risk human papillomavirus (hr-HPV)-related cervical carcinogenesis and metastasis. Methods. CD68+ and CD163+ macrophages were examined immunohistochemically in a series of 130 samples, including 26 cases of normal cervical tissues, 59 cases of cervical intraepithelial neoplasia (CIN), and 45 cases of squamous cell carcinoma (SCC), and the results were statistically analyzed. The macrophage count was corrected for the epithelial and stromal compartments respectively. Clinical data were also obtained. Results. High counts of CD68+ and CD163+ macrophages were associated with hr-HPV infection (both p < 0.05) and positively correlated with cervical carcinogenesis (Spearman's rho = 0.478, p = 0.000; Spearman's rho = 0.676, p =0.000, respectively). The immunostaining pattern of CD163 exhibited clearer background than that of CD68. CD163+ macrophages showed a more obviously increasing migration into the epithelium along with the progression of CIN to invasive cancer. Notably, a high index of CD163+ macrophages was significantly associated with higher FIGO stages (p = 0.009) and lymph node metastasis (p = 0.012), but a similar finding was not found for CD68+ macrophages (p = 0.067, p = 0.079, respectively). Conclusions. Our study supported a critical role of TAMs as a prospective predictor for hr-HPV-related cervical carcinogenesis. CD163, as a promising TAMs marker, is superior to CD68 for predicting the malignant transformation and metastatic potential of cervical cancer.

Orthotopic Xenograft Mouse Model of Cervical Cancer for Studying the Role of MicroRNA-21 in Promoting Lymph Node Metastasis.

Cervical cancer is the most frequent cause of gynecologic cancer-associated death worldwide. Animal models that demonstrate metastatic patterns consistent with the clinical course of cervical cancer are urgently needed to conduct studies focused on understanding the mechanisms of the disease and identifying optimal treatments. To address this, we established an orthotopic xenograft model of cervical cancer in female NOD-SCID mice using SiHa and ME180 cell lines stably expressing green fluorescent protein to evaluate the role of microRNA-21 (miR-21) in spontaneous lymph node metastasis in vivo. In this case, SiHa and ME180 cells were transduced by lentivirus to stably express green fluorescent protein and miR-21. Overexpression of miR-21 promoted proliferation, migration, and invasion of SiHa and ME180 cells in vitro. Finally, an orthotopic xenograft model of human cervical cancer was successfully established in NOD-SCID mice. Using this model, we confirmed that overexpression of miR-21 resulted in an increase in the size of primary tumors and in the frequency of spontaneous lymph node metastasis at the time of excision. Therefore, the use of the orthotopic xenograft model should allow for the investigation of novel factors that affect metastasis of cervical cancer and presents an opportunity to evaluate potential therapeutic agents that may inhibit the spread of the disease.

[Study of integrated state of HPV-16 infection in cervical cancer and precancerous tissues].

OBJECTIVE: To investigate the prevalence of physical state of HPV-16 DNA in cervical cancer and cervical precancerous carcinoma. METHODS: Multiplex PCR was adopted to detect the physical state of HPV in samples from 252 patients with cervical carcinoma, including 48 samples of cervical cancer, 204 cervical intraepithelial neoplasia (CIN ) (125 CIN I, 46 CIN II and 33 CIN III) and 20 normal samples from the subjects with hysteromyoma undergoing hysterectomy, respectively. RESULTS: Among 48 patients with cervical cancer, 31 (65.6%) were infected with HPV-16. Eighteen among 31 (58.1%) HPV-16 infected patients with cervical cancer were found to have integrated infection of HPV-16. The positive rates of HPV-16 infection in the patients with CIN I, CIN II and CIN III were 19.2%, 34.8% and 42.4%, and the integrated infection rates of HPV-16 were 16.7%, 18.8% and 35.7%, respectively. Compared with patients with different grades of CIN, the integrated rate of HPV-16 infection in those with cervical cancer was significantly elevated. CONCLUSION: Among the patients with HPV-16 infection, the integrated state of HPV-16 is positively correlated with the severity of cervical lesions. Combined HPV typing test and detection of integrated viral state contribute to predicting the prognosis of patients with cervical precancerous lesions and increasing the accuracy of screening cervical cancer on the basis of HPV DNA detection.