Functional intratumoral lymphatics in patient-derived xenograft models of squamous cell carcinoma of the uterine cervix: implications for lymph node metastasis

Lymphatic vessels in cancer

The lymphatic system, composed of initial and collecting lymphatic vessels as well as lymph nodes that are present in almost every tissue of the human body, acts as an essential transport system for fluids, biomolecules and cells between peripheral tissues and the central circulation. Consequently, it is required for normal body physiology but is also involved in the pathogenesis of various diseases, most notably cancer. The important role of tumor-associated lymphatic vessels and lymphangiogenesis in the formation of lymph node metastasis has been elucidated during the last two decades, whereas the underlying mechanisms and the relation between lymphatic and peripheral organ dissemination of cancer cells are incompletely understood. Lymphatic vessels are also important for tumor-host communication, relaying molecular information from a primary or metastatic tumor to regional lymph nodes and the circulatory system. Beyond antigen transport, lymphatic endothelial cells, particularly those residing in lymph node sinuses, have recently been recognized as direct regulators of tumor immunity and immunotherapy responsiveness, presenting tumor antigens and expressing several immune-modulatory signals including PD-L1. In this review, we summarize recent discoveries in this rapidly evolving field and highlight strategies and challenges of therapeutic targeting of lymphatic vessels or specific lymphatic functions in cancer patients.

Nectin-4 promotes lymphangiogenesis and lymphatic metastasis in breast cancer by regulating CXCR4-LYVE-1 axis

Tumor-induced lymphangiogenesis promotes tumor progression by generating new lymphatic vessels that helps in tumor dissemination to regional lymph nodes and distant sites. Recently, the role of Nectin-4 in cancer metastasis and angiogenesis has been studied, but its role in lymphangiogenesis is unknown. Here, we systematically delineated the role of Nectin-4 in lymphangiogenesis and its regulation in invasive duct carcinoma (IDC). Nectin-4 expression positively correlated with occurrence risk factors associated with breast cancer (alcohol, smoke, lifestyle habit, etc), CXCR4 expression, and LYVE-1-lymphatic vessel density (LVD). LVD was significantly higher in axillary lymph node (ALN) than primary tumor. Depleting Nectin-4, VEGF-C or both attenuated the important lymphangiogenic marker LYVE-1 expression, tube formation, and migration of ALN derived primary cells. Nectin-4 stimulated the expressions of CXCR4 and CXCL12 under hypoxic conditions in ALN derived primary cells. Further, Nectin-4 augmented expressions of lymphatic metastatic markers (e.g. eNOS, TGF-β, CD-105) and MMPs. Induced expressions of Nectin-4 along with other representative metastatic markers were noted in lymph and blood circulating tumor cells (LCTCs and BCTCs) of local and distant metastatic samples. Thus, Nectin-4 displayed a predominant role in promoting tumor-induced lymphangiogenesis and lymphatic metastasis by modulating CXCR4/CXCL12-LYVE-1- axis.

Characterizing Endocrine Status, Tumor Hypoxia and Immunogenicity for Therapy Success in Epithelial Ovarian Cancer

Epithelial ovarian cancer is predominantly diagnosed at advanced stages which creates significant therapeutic challenges. As a result, the 5-year survival rate is low. Within ovarian cancer, significant tumor heterogeneity exists, and the tumor microenvironment is diverse. Tumor heterogeneity leads to diversity in therapy response within the tumor, which can lead to resistance or recurrence. Advancements in therapy development and tumor profiling have initiated a shift from a "one-size-fits-all" approach towards precision patient-based therapies. Here, we review aspects of ovarian tumor heterogeneity that facilitate tumorigenesis and contribute to treatment failure. These tumor characteristics should be considered when designing novel therapies or characterizing mechanisms of treatment resistance. Individual patients vary considerably in terms of age, fertility and contraceptive use which innately affects the endocrine milieu in the ovary. Similarly, individual tumors differ significantly in their immune profile, which can impact the efficacy of immunotherapies. Tumor size, presence of malignant ascites and vascular density further alters the tumor microenvironment, creating areas of significant hypoxia that is notorious for increasing tumorigenesis, resistance to standard of care therapies and promoting stemness and metastases. We further expand on strategies aimed at improving oxygenation status in tumors to dampen downstream effects of hypoxia and set the stage for better response to therapy.

Timed Ang2-Targeted Therapy Identifies the Angiopoietin-Tie Pathway as Key Regulator of Fatal Lymphogenous Metastasis

Recent clinical and preclinical advances have highlighted the existence of a previously hypothesized lymphogenous route of metastasis. However, due to a lack of suitable preclinical modeling tools, its contribution to long-term disease outcome and relevance for therapy remain controversial. Here, we established a genetically engineered mouse model (GEMM) fragment-based tumor model uniquely sustaining a functional network of intratumoral lymphatics that facilitates seeding of fatal peripheral metastases. Multiregimen survival studies and correlative patient data identified primary tumor-derived Angiopoietin-2 (Ang2) as a potent therapeutic target to restrict lymphogenous tumor cell dissemination. Mechanistically, tumor-associated lymphatic endothelial cells (EC), in contrast to blood vascular EC, were found to be critically addicted to the Angiopoietin-Tie pathway. Genetic manipulation experiments in combination with single-cell mapping revealed agonistically acting Ang2-Tie2 signaling as key regulator of lymphatic maintenance. Correspondingly, acute presurgical Ang2 neutralization was sufficient to prolong survival by regressing established intratumoral lymphatics, hence identifying a therapeutic regimen that warrants further clinical evaluation. SIGNIFICANCE: Exploiting multiple mouse tumor models including a unique GEMM-derived allograft system in combination with preclinical therapy designs closely matching the human situation, this study provides fundamental insight into the biology of tumor-associated lymphatic EC and defines an innovative presurgical therapeutic window of migrastatic Ang2 neutralization to restrict lymphogenous metastasis.This article is highlighted in the In This Issue feature, p. 211.

Detection and prognostic value of intratumoral and peritumoral lymphangiogenesis in colorectal cancer

Background

Colorectal cancer (CRC) with lymphatic invasion is one of the critical prognostic factors in lymph node metastasis. Lymphangiogenesis has a significant effect on lymphatic metastasis and tumor progression. However, the significance of intratumoral and peritumoral lymphangiogenesis has been controversial in CRC. The aim of this study is to investigate the different role of introtumoral and peritumoral lymphangiogenesis in CRC progression and prognosis.

Methods

Lymphangiogenesis of 120 CRC specimens, as measured by lymphatic vessel density (LVD), was examined by immunostaining for podoplanin, a lymphatic vessel-specific marker. The mean number of lymphatic vessels of three hotspots was measured in intratumoral and peritumoral areas as intratumoral LVD (LVDit) and peritumoral LVD (LVDpt), respectively. The association of LVDit and LVDpt with the clinicopathological findings and prognosis was investigated.

Results

Compared to the peritumoral lymphatics, the intratumoral lymphatics were small, collapsed and irregular. The mean LVDpt was higher than the mean LVDit (P<0.001). LVDit was positively correlated with tumor size (P=0.009), tumor histologic grade (P=0.023), and overall survival (P=0.036). LVDpt was correlated with lymph node metastasis (P<0.001), tumor stage (P=0.004), and overall survival (P=0.016).

Conclusions

LVDpt plays a prominent role in lymph node metastasis, whereas LVDit is more closely correlated with tumor growth and histopathological differentiation. Both LVDpt and LVDit contribute to CRC progression and prognosis.

Analysis of diagnostic and prognostic value of lncRNA MEG3 in cervical cancer

The present study aimed to explore the diagnostic and prognostic value of lncRNA maternally expressed 3 (MEG3) in cervical cancer. Eighty-four patients with cervical cancer from February 2013 to March 2014 were enrolled in the observation group (OG), and another 58 female subjects who underwent physical examination at Huangshi Central Hospital were enrolled as the control group (CG). The serum MEG3 expression of patients in the two groups was detected by RT-qPCR, and the ability of MEG3 to aid in the diagnosis of cervical cancer, lymph node metastasis and FIGO staging, as well as to predict mortality was evaluated by ROC curve. In addition, the patients in the OG were divided into high- and low-expression groups according to the median value of MEG3. Kaplan Meier was employed to analyze the survival status, and Cox regression to analyze the independent prognostic factors of cervical cancer patients. The results of the present study revealed that the serum MEG3 expression in the OG was significantly lower than that of the CG (P<0.05). The area under the curve (AUC) of MEG3 in diagnosing cervical cancer was 0.844, the AUC in predicting mortality was 0.858, while that in diagnosing lymph node transfer was 0.707, and that in diagnosing FIGO staging was 0.791. The 5-year survival rate of the high-expression group was higher than that of the low-expression group (P=0.020). Multivariate analysis indicated that MEG3 (HR, 0.173; 95 CI%, 0.028-0.919), lymph node metastasis (HR, 2.259; 95 CI%, 1.004-5.025) and FIGO staging (HR, 0.008; 95 CI%, 1.453-6.248) were independent prognostic factors for cervical cancer patients. Collectively, lncRNA MEG3 may be a diagnostic marker and prognostic indicator for cervical cancer, and has a certain diagnostic value for lymph node metastasis and FIGO staging. Lymph node metastasis, FIGO stage III and IV, and low MEG3 levels were revealed to be independent prognostic factors for cervical cancer patients.

Markers of Angiogenesis, Lymphangiogenesis, and Epithelial-Mesenchymal Transition (Plasticity) in CIN and Early Invasive Carcinoma of the Cervix: Exploring Putative Molecular Mechanisms Involved in Early Tumor Invasion

The establishment of a proangiogenic phenotype and epithelial-to-mesenchymal transition (EMT) are considered as critical events that promote the induction of invasive growth in epithelial tumors, and stimulation of lymphangiogenesis is believed to confer the capacity for early dissemination to cancer cells. Recent research has revealed substantial interdependence between these processes at the molecular level as they rely on common signaling networks. Of great interest are the molecular mechanisms of (lymph-)angiogenesis and EMT associated with the earliest stages of transition from intraepithelial development to invasive growth, as they could provide the source of potentially valuable tools for targeting tumor metastasis. However, in the case of early-stage cervical cancer, the players of (lymph-)angiogenesis and EMT processes still remain substantially uncharacterized. In this study, we used RNA sequencing to compare transcriptomes of HPV(+) preinvasive neoplastic lesions and early-stage invasive carcinoma of the cervix and to identify (lymph-)angiogenesis- and EMT-related genes and pathways that may underlie early acquisition of invasive phenotype and metastatic properties by cervical cancer cells. Second, we applied flow cytometric analysis to evaluate the expression of three key lymphangiogenesis/EMT markers (VEGFR3, MET, and SLUG) in epithelial cells derived from enzymatically treated tissue specimens. Overall, among 201 differentially expressed genes, a considerable number of (lymph-)angiogenesis and EMT regulatory factors were identified, including genes encoding cytokines, growth factor receptors, transcription factors, and adhesion molecules. Pathway analysis confirmed enrichment for angiogenesis, epithelial differentiation, and cell guidance pathways at transition from intraepithelial neoplasia to invasive carcinoma and suggested immune-regulatory/inflammatory pathways to be implicated in initiation of invasive growth of cervical cancer. Flow cytometry showed cell phenotype-specific expression pattern for VEGFR3, MET, and SLUG and revealed correlation with the amount of tumor-infiltrating lymphocytes at the early stages of cervical cancer progression. Taken together, these results extend our understanding of driving forces of angiogenesis and metastasis in HPV-associated cervical cancer and may be useful for developing new treatments.

Intratumor Heterogeneity in Interstitial Fluid Pressure in Cervical and Pancreatic Carcinoma Xenografts

Preclinical studies have suggested that interstitial fluid pressure (IFP) is uniformly elevated in the central region of tumors, whereas clinical studies have revealed that IFP may vary among different measurement sites in the tumor center. IFP measurements are technically difficult, and it has been claimed that the intratumor heterogeneity in IFP reported for human tumors is due to technical problems. The main purpose of this study was to determine conclusively whether IFP may be heterogeneously elevated in the central tumor region, and if so, to reveal possible mechanisms and possible consequences. Tumors of two xenograft models were included in the study: HL-16 cervical carcinoma and Panc-1 pancreatic carcinoma. IFP was measured with Millar SPC 320 catheters in two positions in each tumor and related to tumor histology or the metastatic status of the host mouse. Some tumors of both models showed significant intratumor heterogeneity in IFP, and this heterogeneity was associated with a compartmentalized histological appearance (i.e., the tissue was divided into compartments separated by thick connective tissue bands) in HL-16 tumors and with a dense collagen-I-rich extracellular matrix in Panc-1 tumors, suggesting that these connective tissue structures prevented efficient interstitial convection. Furthermore, some tumors of both models developed lymph node metastases, and of the two IFP values measured in each tumor, only the higher value was significantly higher in metastatic than in non-metastatic tumors, suggesting that metastatic propensity was determined by the tumor region having the highest IFP.

Mammalian Eps15 homology domain 1 potentiates angiogenesis of non-small cell lung cancer by regulating β2AR signaling

BACKGROUND

Non-small cell lung cancer (NSCLC) is a devastating disease with a heterogeneous prognosis, and the molecular mechanisms underlying tumor progression remain elusive. Mammalian Eps15 homology domain 1 (EHD1) plays a promotive role in tumor progression, but its role in cancer angiogenesis remains unknown. This study thus explored the role of EHD1 in angiogenesis in NSCLC.

METHODS

The changes in angiogenesis were evaluated through human umbilical vein endothelial cell (HUVEC) proliferation, migration and tube formation assays. The impact of EHD1 on β2-adrenoceptor (β2AR) signaling was evaluated by Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR) analysis, and enzyme-linked immunosorbent assay (ELISA). The interaction between EHD1 and β2AR was confirmed by immunofluorescence (IF) and coimmunoprecipitation (Co-IP) experiments, and confocal microscopy immunofluorescence studies revealed that β2AR colocalized with the recycling endosome marker Rab11, which indicated β2AR endocytosis. Xenograft tumor models were used to investigate the role of EHD1 in NSCLC tumor growth.

RESULTS

The microarray analysis revealed that EHD1 was significantly correlated with tumor angiogenesis, and loss- and gain-of-function experiments demonstrated that EHD1 potentiates HUVEC proliferation, migration and tube formation. EHD1 knockdown inhibited β2AR signaling activity, and EHD1 upregulation promoted vascular endothelial growth factor A (VEGFA) and β2AR expression. Interestingly, EHD1 interacted with β2AR and played a novel and critical role in β2AR endocytic recycling to prevent receptor degradation. Aberrant VEGFA or β2AR expression significantly affected EHD1-mediated tumor angiogenesis. The proangiogenic role of EHD1 was confirmed in xenograft tumor models, and immunohistochemistry (IHC) analysis confirmed that EHD1 expression was positively correlated with VEGFA expression, microvessel density (MVD) and β2AR expression in patient specimens.

CONCLUSION

Collectively, the data obtained in this study suggest that EHD1 plays a critical role in NSCLC angiogenesis via β2AR signaling and highlight a potential target for antiangiogenic therapy.

Diffusion-Weighted MRI Is Insensitive to Changes in the Tumor Microenvironment Induced by Antiangiogenic Therapy

Antiangiogenic treatment (AAT) used in combination with radiation therapy or chemotherapy is a promising strategy for the treatment of several cancer diseases. The vascularity and oxygenation of tumors may be changed significantly by AAT, and consequently, a noninvasive method for monitoring AAT-induced changes in these microenvironmental parameters is needed. The purpose of this study was to evaluate the potential usefulness of diffusion-weighted magnetic resonance imaging (DW-MRI). DW-MRI was conducted with a Bruker Biospec 7.05-T scanner using four diffusion weightings and diffusion sensitization gradients in three orthogonal directions. Maps of the apparent diffusion coefficient (ADC) were calculated by using a monoexponential diffusion model. Two cervical carcinoma xenograft models (BK-12, HL-16) were treated with bevacizumab, and two pancreatic carcinoma xenograft models (BxPC-3, Panc-1) were treated with sunitinib. Pimonidazole and CD31 were used as markers of hypoxia and blood vessels, respectively, and fraction of hypoxic tissue (HF_Pim) and microvascular density (MVD) were quantified by analyzing immunohistochemical preparations. MVD decreased significantly after AAT in BK-12, HL-16, and BxPC-3 tumors, and this decrease was sufficiently large to cause a significant increase in HF_Pim in BK-12 and BxPC-3 tumors. The ADC maps of treated tumors and untreated control tumors were not significantly different in any of these three tumor models, suggesting that the AAT-induced microenvironmental changes were not detectable by DW-MRI. DW-MRI is insensitive to changes in tumor vascularity and oxygenation induced by bevacizumab or sunitinib treatment.

DCE-MRI of Sunitinib-Induced Changes in Tumor Microvasculature and Hypoxia: A Study of Pancreatic Ductal Adenocarcinoma Xenografts

The purpose of this study was dual: to investigate (a) whether sunitinib may induce changes in tumor microvasculature and hypoxia in pancreatic ductal adenocarcinoma (PDAC) and (b) whether any changes can be detected by DCE-MRI. Sunitinib-treated and untreated control tumors of two PDAC xenograft models (BxPC-3 and Panc-1) were subjected to DCE-MRI before the imaged tumors were prepared for quantitative analysis of immunohistochemical preparations. Pimonidazole was used as a hypoxia marker, and fraction of hypoxic tissue (HFPim), density of CD31-positive microvessels (MVDCD31), and density of αSMA-positive microvessels (MVDαSMA) were measured. Parametric images of Ktrans and ve were derived from the DCE-MRI data by using the Tofts pharmacokinetic model. BxPC-3 tumors showed increased HFPim, decreased MVDCD31, unchanged MVDαSMA, and increased vessel maturation index (VMI = MVDαSMA/MVDCD31) after sunitinib treatment. The increase in VMI was seen because sunitinib induced selective pruning rather than maturation of αSMA-negative microvessels. Even though the microvessels in sunitinib-treated tumors were less abnormal than those in untreated tumors, this microvessel normalization did not improve the function of the microvascular network or normalize the tumor microenvironment. In Panc-1 tumors, HFPim, MVDCD31, MVDαSMA, and VMI were unchanged after sunitinib treatment. Median Ktrans increased with increasing MVDCD31 and decreased with increasing HFPim, and the correlations were similar for treated and untreated BXPC-3 and Panc-1 tumors. These observations suggest that sunitinib may induce significant changes in the microenvironment of PDACs, and furthermore, that Ktrans may be an adequate measure of tumor vascular density and hypoxia in untreated as well as sunitinib-treated PDACs.

Increasing aggressiveness of patient-derived xenograft models of cervix carcinoma during serial transplantation

Four patient-derived xenograft (PDX) models (BK-12, ED-15, HL-16, LA-19) of carcinoma of the uterine cervix have been developed in our laboratory, and their stability during serial transplantation in vivo was investigated in this study. Two frozen cell stocks were established, one from xenografted tumors in passage 2 (early generation) and the other from xenografted tumors transplanted serially in mice for approximately two years (late generation), and the biology of late generation tumors was compared with that of early generation tumors. Late generation tumors showed higher incidence of lymph node metastases than early generation tumors in three models (ED-15, HL-16, LA-19), and the increased metastatic propensity was associated with increased tumor growth rate, increased microvascular density, and increased expression of angiogenesis-related and cancer stem cell-related genes. Furthermore, late generation tumors showed decreased fraction of pimonidazole-positive tissue (i.e., decreased fraction of hypoxic tissue) in two models (HL-16, LA-19) and decreased fraction of collagen-I-positive tissue (i.e., less extensive extracellular matrix) in two models (ED-15, HL-16). This study showed that serially transplanted PDXs may not necessarily mirror the donor patients’ diseases, and consequently, proper use of serially transplanted PDX models in translational cancer research requires careful molecular monitoring of the models.

Bridging the divide: preclinical research discrepancies between triple-negative breast cancer cell lines and patient tumors

Triple-negative breast cancer (TNBC) is the most refractory subtype of breast cancer and disproportionately accounts for the majority of breast cancer related deaths. Effective treatment of this disease remains an unmet medical need. Over the past several decades, TNBC cell lines have been used as the foundation for drug development and disease modeling. However, ever-mounting research demonstrates striking differences between cell lines and clinical TNBC tumors, disconnecting bench research and actual clinical responses. In this review, we discuss the limitations of cell lines and the importance of using patients' tumors for translational research, and highlight the usage of patient-derived xenograft (PDXs) models that have emerged as a clinically relevant platform for preclinical studies. PDX tumors possess tumor heterogeneity with similar cellular, molecular, genetic and epigenetic properties akin to those found within patients' tumors. Moreover, PDX and clinical tumors possess abnormal vasculature with higher blood vessel permeability, a feature that is not always demonstrated in in vivo cell line xenografts. Development of clinically relevant, novel drug-nanoparticles capable of accumulating in PDX tumors through the enhanced permeability and retention effect in tumor vasculature may lead to new and effective TNBC treatments.

Diffusion-weighted MRI-derived ADC values reflect collagen I content in PDX models of uterine cervical cancer

Apparent diffusion coefficient (ADC) values derived from diffusion-weighted magnetic resonance imaging (DW-MRI) are known to reflect the cellular environment of biological tissues. However, emerging evidence accentuates the influence of stromal elements on ADC values. The current study sought to elucidate whether a correlation exists between ADC and the fraction of collagen I-positive tissue across different tumor models of uterine cervical cancer. Early and late generation tumors of four patient-derived xenograft (PDX) models of squamous cell carcinoma (BK-12, ED-15, HL-16, and LA-19) were included. DW-MRI was performed with diffusion encoding constants (b) of 200, 400, 700, and 1000 s/mm2 and diffusion gradient sensitization in three orthogonal directions. The fraction of collagen I-positive connective tissue was determined by immunohistochemistry. Mono-exponential decay curves, from which the ADC value of tumor voxels was calculated, yielded good fits to the diffusion data. A significant inverse correlation was detected between median tumor ADC and collagen I fraction across the four PDX models, indicating that collagen fibers in the extracellular space have the ability to inhibit the movement of water molecules in these xenografts. The results encourage further exploration of DW-MRI as a non-invasive imaging method for characterizing the stromal microenvironment of tumors.

DCE-MRI of patient-derived xenograft models of uterine cervix carcinoma: associations with parameters of the tumor microenvironment

BACKGROUND

Abnormalities in the tumor microenvironment are associated with resistance to treatment, aggressive growth, and poor clinical outcome in patients with advanced cervical cancer. The potential of dynamic contrast-enhanced (DCE) MRI to assess the microvascular density (MVD), interstitial fluid pressure (IFP), and hypoxic fraction of patient-derived cervical cancer xenografts was investigated in the present study.

METHODS

Four patient-derived xenograft (PDX) models of squamous cell carcinoma of the uterine cervix (BK-12, ED-15, HL-16, and LA-19) were subjected to Gd-DOTA-based DCE-MRI using a 7.05 T preclinical scanner. Parametric images of the volume transfer constant (K ^trans) and the fractional distribution volume (v _e) of the contrast agent were produced by pharmacokinetic analyses utilizing the standard Tofts model. Whole tumor median values of the DCE-MRI parameters were compared with MVD and the fraction of hypoxic tumor tissue, as determined histologically, and IFP, as measured with a Millar catheter.

RESULTS

Both on the PDX model level and the single tumor level, a significant inverse correlation was found between K ^trans and hypoxic fraction. The extent of hypoxia was also associated with the fraction of voxels with unphysiological v _e values (v _e > 1.0). None of the DCE-MRI parameters were related to MVD or IFP.

CONCLUSIONS

DCE-MRI may provide valuable information on the hypoxic fraction of squamous cell carcinoma of the uterine cervix, and thereby facilitate individualized patient management.

Prognostic value of lymphovascular invasion in Bismuth-Corlette type IV hilar cholangiocarcinoma

AIM

To assess the prognostic value of lymphovascular invasion (LVI) in Bismuth-Corlette type IV hilar cholangiocarcinoma (HC) patients.

METHODS

A retrospective analysis was performed on 142 consecutively recruited type IV HC patients undergoing radical resection with at least 5 years of follow-up. Survival analysis was performed by the Kaplan-Meier method, and the association between the clinicopathologic variables and survival was evaluated by log-rank test. Multivariate analysis was adopted to identify the independent prognostic factors for overall survival (OS) and disease-free survival (DFS). Multiple logistic regression analysis was performed to determine the association between LVI and potential variables.

RESULTS

LVI was confirmed histopathologically in 29 (20.4%) patients. Multivariate analysis showed that positive resection margin (HR = 6.255, 95%CI: 3.485-11.229, P < 0.001), N1 stage (HR = 2.902, 95%CI: 1.132-7.439, P = 0.027), tumor size > 30 mm (HR = 1.942, 95%CI: 1.176-3.209, P = 0.010) and LVI positivity (HR = 2.799, 95%CI: 1.588-4.935, P < 0.001) were adverse prognostic factors for DFS. The independent risk factors for OS were positive resection margin (HR = 6.776, 95%CI: 3.988-11.479, P < 0.001), N1 stage (HR = 2.827, 95%CI: 1.243-6.429, P = 0.013), tumor size > 30 mm (HR = 1.739, 95%CI: 1.101-2.745, P = 0.018) and LVI positivity (HR = 2.908, 95%CI: 1.712-4.938, P < 0.001). LVI was associated with N1 stage and tumor size > 30 mm. Multiple logistic regression analysis indicated that N1 stage (HR = 3.312, 95%CI: 1.338-8.198, P = 0.026) and tumor size > 30 mm (HR = 3.258, 95%CI: 1.288-8.236, P = 0.013) were associated with LVI.

CONCLUSION

LVI is associated with N1 stage and tumor size > 30 mm and adversely influences DFS and OS in type IV HC patients.

Lymph node metastasis and the physicochemical micro-environment of pancreatic ductal adenocarcinoma xenografts

Pancreatic ductal adenocarcinoma (PDAC) patients develop lymph node metastases early and have a particularly poor prognosis. The poor prognosis has been shown to be associated with the physicochemical microenvironment of the tumor tissue, which is characterized by desmoplasia, abnormal microvasculature, extensive hypoxia, and highly elevated interstitial fluid pressure (IFP). In this study, we searched for associations between lymph node metastasis and features of the physicochemical microenvironment in an attempt to identify mechanisms leading to metastatic dissemination and growth. BxPC-3 and Capan-2 PDAC xenografts were used as preclinical models of human PDAC. In both models, lymph node metastasis was associated with high IFP rather than high fraction of hypoxic tissue or high microvascular density. Seven angiogenesis-related genes associated with high IFP-associated lymph node metastasis were detected by quantitative PCR in each of the models, and these genes were all up-regulated in high IFP/highly metastatic tumors. Three genes were mutual for the BxPC-3 and Capan-2 models: transforming growth factor beta, angiogenin, and insulin-like growth factor 1. Further comprehensive studies are needed to determine whether there is a causal relationship between the up-regulation of these genes and high IFP and/or high propensity for lymph node metastasis in PDAC.

Lymph Nodes and Cancer Metastasis: New Perspectives on the Role of Intranodal Lymphatic Sinuses

The lymphatic system is essential for transporting interstitial fluid, soluble antigen, and immune cells from peripheral tissues to lymph nodes (LNs). Functional integrity of LNs is dependent on intact lymphatics and effective lymph drainage. Molecular mechanisms that facilitate interactions between tumor cells and lymphatic endothelial cells (LECs) during tumor progression still remain to be identified. The cellular and molecular structures of LNs are optimized to trigger a rapid and efficient immune response, and to participate in the process of tumor metastasis by stimulating lymphangiogenesis and establishing a premetastatic niche in LNs. Several molecules, e.g., S1P, CCR7-CCL19/CCL21, CXCL12/CXCR4, IL-7, IFN-γ, TGF-β, and integrin α4β1 play an important role in controlling the activity of LN stromal cells including LECs, fibroblastic reticular cells (FRCs) and follicular dendritic cells (DCs). The functional stromal cells are critical for reconstruction and remodeling of the LN that creates a unique microenvironment of tumor cells and LECs for cancer metastasis. LN metastasis is a major determinant for the prognosis of most human cancers and clinical management. Ongoing work to elucidate the function and molecular regulation of LN lymphatic sinuses will provide insight into cancer development mechanisms and improve therapeutic approaches for human malignancy.

Riccardin D-N induces lysosomal membrane permeabilization by inhibiting acid sphingomyelinase and interfering with sphingomyelin metabolism in vivo

Lysosomes are important targets for anticancer drug discovery. Our previous study showed that Riccardin D-N (RD-N), a natural macrocylic bisbibenzyl derivative produced by Mannich reaction, induced cell death by accumulating in lysosomes. Experiments were performed on human lung squamous cell carcinoma tissue from left inferior lobar bronchus of patient xenografts and H460 cells. RD-N was administrated for 25days. The specimens of xenografts in Balb/c athymic (nu+/nu+) male mice were removed for immunohistochemistry, subcellular fractionation, enzyme activities and Western blotting analysis. mRFP-GFP-LC3 reporter was used to examine autophagy in H460 cells. Sphingomyelin assay was evaluated by thin-layer chromatography and assay kit. Lysosomal membrane permeabilization (LMP) caused by acid sphingomyelinase (ASM) inhibition and subsequent changes of sphingomyelin (SM) metabolism selectively destabilized the cancer cell lysosomes in RD-N-treated H460 cells in vitro and tumor xenograft model in vivo. The destabilized lysosomes induced the release of cathepsins from the lysosomes into the cytosol and further triggered cell death. These results explain the underlying mechanism of RD-N induced LMP. It can be concluded that a more lysosomotropic derivative was synthesized by introduction of an amine group, which could have more potential applications in cancer therapy.