Danfang Zhang

Chemokine CXCL12 and its receptor CXCR4 expression are associated with perineural invasion of prostate cancer

ObjectiveTo identify the roles of CXCL12 and CXCR4 and the associated mechanism involved in perineural invasion of prostate cancer.MethodsThe distribution and expression of CXCL12, CXCR4, MMP-2 and MMP-9 in human prostate cancer and in tumor cells invading nerve tissue were studied with immunohistochemical staining. The effects of exogenous CXCL12 and CXCR4 antagonist AMD3100 on PC3 prostate cancer cells invasiveness were assessed in vitro and in vivo.ResultsThe expression of CXCL12, CXCR4, MMP-2, and MMP-9 in human prostate cancer were higher than those in hyperplastic prostate tissues (P < 0.05). In vitro CXCL12 could stimulate the PC3 cells invasiveness (P < 0.05) while AMD3100 could inhibit invasiveness. In vivo, the number of nerves around the tumor tissue in the group treated with CXCL12 was significantly higher than that found in the control group (P < 0.05). Both the control group and the CXCL12-treated group had more nerves number near the tumor tissue than it found in the AMD3100-treated group. The positive cell number of CXCL12, CXCR4, MMP-2, MMP-9, and NGF expression ranked from highest to lowest, were the CXCL12-treated, the control, and the AMD3100-treated group(P < 0.05).ConclusionCXCL12 and its receptor CXCR4 along with MMP-2 and MMP-9 are related with prostate cancer perineural invasion.

Vasculogenic Mimicry: a New Prognostic Sign of Gastric Adenocarcinoma

Vasculogenic mimicry (VM) has been generally recognized as a new pattern of tumor neovascularization. It presents in many human malignancies. Till now, there is no report about VM in gastric adenocarcinoma (GAC). In this study, we collected 173 paraffin-embedded human GAC samples, with detailed follow-up and clinicopathologic data. CD31/ periodic acid-Schiff (PAS) double staining, immunohistochemical staining of CK8 & 18 and laminin were performed to validate the existence of VM in GAC. Microvascular density (MVD) and vasulogenic mimicry density (VMD) were counted respectively. VM was observed in 40 of the 173 GAC patients, especially in poorly differentiated GAC (P = 0.014). Patients with VM were prone to hematogenous metastasis and distant recurrence compared with patients without VM (P = 0.020, 0.029). Higher VMD values was also associated with hematogenous metastasis (P = 0.003). Immunohistochemical staining index (SI) of hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, and MMP-9 were compared between the VM and non-VM group. The SI of four factors were all higher in the VM group than those of non-VM group (P = 0.000, 0.000, 0.004, 0.009, respectively). The Kaplan-Meier survival analysis showed that the VM group has shorter life span compared with non-VM group (P = 0.022). Cox proportional hazards model indicated that the presence of VM and TNM stage were independent predictors of poor prognosis (P = 0.039 and 0.004) for GAC. In conclusion, VM exists in GAC, especially in poorly differentiated GAC. Additionally, it is an unfavorable prognostic indictor for GAC. Hypoxia may play a role in VM formation in GAC.

Hypoxia influences linearly patterned programmed cell necrosis and tumor blood supply patterns formation in melanoma

To investigate the possibility that tumor cells undergoing linearly patterned programmed cell necrosis (LPPCN) establish a spatial foundation for vasculogenic mimicry (VM) and to reveal that hypoxia influences LPPCN formation as well as Endo G and DNase 1 expression, 78 C57 mice were divided evenly into two groups and engrafted with B16 melanoma. Starting 9 days after inoculation, subgroups of mice were killed every 2 days. LPPCN and the tumor blood supply vessel types were counted and Endo G and DNase 1 mRNA expression were measured. Additionally, 124 cases of human melanoma samples were collected to assess the clinical significance of LPPCN and VM. The data revealed that regions of LPPCN were positive for caspase-3, caspase-9 and Bax, and negative for TUNEL staining. Electron microscopy images indicated that these cells took on the morphologic changes of necrosis. There was more DNase I mRNA expression in the hypoxic group than in the control group (P<0.05) in vitro, and the expression of Endo G mRNA in the hypoxic groups was significantly higher than that in the control groups both in vitro and in vivo (P<0.05). VM and LPPCN cell numbers in the ischemic group were higher than those in the control group in the early stage of tumor growth. Finally, the survival time for patients whose samples showed LPPCN and VM was significantly shorter than that of patients with one or neither of those factors. We speculated that under hypoxic conditions, some melanoma cells might undergo LPPCN, thus providing a spatial foundation for VM channel formation.

Twist1 expression induced by sunitinib accelerates tumor cell vasculogenic mimicry by increasing the population of CD133+ cells in triple-negative breast cancer

BackgroundHypoxia induced by antiangiogenic agents is linked to the generation of cancer stem cells (CSCs) and treatment failure through unknown mechanisms. The generation of endothelial cell-independent microcirculation in malignant tumors is defined as tumor cell vasculogenic mimicry (VM). In the present study, we analyzed the effects of an antiangiogenic agent on VM in triple-negative breast cancer (TNBC).MethodsMicrocirculation patterns were detected in patients with TNBC and non-TNBC. Tientsin Albino 2 (TA2) mice engrafted with mouse TNBC cells and nude mice engrafted with human breast cancer cell lines with TNBC or non-TNBC phenotypes were administered sunitinib and analyzed to determine tumor progression, survival, microcirculation, and oxygen concentration. Further, we evaluated the effects of hypoxia induced with CoCl2 and the expression levels of the transcription factor Twist1, in the presence or absence of a Twist siRNA, on the population of CD133+ cells and VM in TNBC and non-TNBC cells.ResultsVM was detected in 35.8 and 17.8% of patients with TNBC or with non-TNBC, respectively. The growth of tumors in TNBC and non-TNBC-bearing mice was inhibited by sunitinib. The tumors in TA2 mice engrafted with mouse TNBCs and in mice engrafted a human TNBC cell line (MDA-MB-231) regrew after terminating sunitinib administration. However, this effect was not observed in mice engrafted with a non-TNBC tumor cell line. Tumor metastases in sunitinib-treated TA2 mice was accelerated, and the survival of these mice decreased when sunitinib was withdrawn. VM was the major component of the microcirculation in sunitinib-treated mice with TNBC tumors, and the population of CD133+ cells increased in hypoxic areas. Hypoxia also induced MDA-MB-231 cells to express Twist1, and CD133+ cells present in the MDA-MB-231 cell population induced VM after reoxygenation. Moreover, hypoxia did not induce MDA-MB-231 cells transfected with an sh-Twist1 siRNA cell to form VM and generate CD133+ cells. Conversely, hypoxia induced MCF-7 cells transfected with Twist to form VM and generate CD133+ cells.ConclusionsSunitinib induced hypoxia in TNBCs, and Twist1 expression induced by hypoxia accelerated VM by increasing population of CD133+ cells. VM was responsible for the regrowth of TNBCs sunitinib administration was terminated.

Clusterin Expression and Univariate Analysis of Overall Survival in Human Breast Cancer

The aim of this research is to investigate the significance of clusterin (CLU) expression as a risk factor for breast cancer through tissue microarray technology and univariate analysis of overall survival. Formalin-fixed, paraffin-embedded tissues from 158 cases of breast cancer and 31 cases of normal adjacent tissues assembled into a tissue microarray. Cytoplasmic CLU expression in tumor tissues was measured by immunochemistry. Survival analysis was used to investigate the relationship between CLU expression and prognosis, tumor volume, pathological classification, and recurrence. Survival time of patients with CLU expression, lymph node metastasis, and limited post-surgery chemotherapy (<6 cycles of treatment) was significantly shorter than that of patients with no detectable CLU expression (P=0.000), without lymph node metastasis (P=0.000) and more comprehensive post-surgery chemotherapy (≥6 cycles of treatment) (P=0.035). CLU expression in tumor cells was higher than in normal adjacent breast epithelial cells (P=0.03). The CLU expression staining coefficient of cancer tissues with lymph node metastasis was higher than those without lymph node metastasis (P=0.000). Cytoplasmic CLU expression was found to be a prognostic factor for human breast cancer.

Doxycycline influences microcirculation patterns in B16 melanoma

To examine the effects of doxycycline on invasion-related protein expression and proliferation of melanoma cells and to evaluate its effect on microcirculation patterns in melanoma, we injected murine melanoma B16 cell suspensions into the groin areas of C57BL/6 mice that were randomly divided into treatment and control groups. Eight days after tumor cell injection, we administered doxycycline intraperitoneally (ip) at a dose of 0.15 mg/g/day in the treatment group and administered a physiological saline solution to the control group. Animals were sacrificed on Day 22, and we removed and weighed tumor masses and counted the numbers of vasculogenic mimicry (VM) and endothelium-dependent vessels. Immunohistochemical staining was used to analyze the expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), and proliferating cell nuclear antigen (PCNA). We prepared protein extracts of the tumors, and we examined the activity of MMP-2 and MMP-9 in different groups by gelatin zymography. Real-time polymerase chain reaction (PCR) was used to detect MMP-2 and MMP-9 mRNA level in the fresh tumor tissue. Doxycycline treatment partly suppressed the growth of engrafted B16 melanoma, with an inhibition rate of 35.63%. There were more VM and endothelium-dependent vessels in the control group than in the treatment group. The expression level of MMP-2 and MMP-9 in the treatment group was lower than that in the control group (P < 0.01, P < 0.05). Compared with the control group, VEGF expression was increased with doxycycline treatment. The enzyme activities of MMP-9, active-MMP-2, and MMP-2/pro-MMP-2 in the treatment group were lower than those in the control group (P < 0.01). MMP-2 and MMP-9 mRNA levels in the treatment group were also lower than those in the control group were. Doxycycline inhibits the growth of engrafted melanoma and results in reduced expression of MMP-2, MMP-9, and VM formations.

Doxycycline as an Inhibitor of the Epithelial-to-Mesenchymal Transition and Vasculogenic Mimicry in Hepatocellular Carcinoma

This study was conducted to examine the effects of doxycycline on the survival time and proliferation of hepatocellular carcinoma (HCC) in vivo and on the biologic functions of HCC in vitro. This study was also designed to evaluate the effects of doxycycline on epithelial-to-mesenchymal transition (EMT)– and vasculogenic mimicry (VM)–related protein expression and on matrix metalloproteinase (MMP) and DNA methyltransferase (DNMT) activity in vitro. Human MHCC97H cells were injected into BALB/c mice, which were divided into treatment and control groups. Doxycycline treatment prolonged the mouse survival time and partly suppressed the growth of engrafted HCC tumor cells, with an inhibition rate of 43.39%. Higher amounts of VM and endothelium-dependent vessels were found in the control group than the treatment group. IHC indicated that epithelial (E)-cadherin expression was increased in the doxycycline-treated mice compared with the control group. In in vitro experiments, doxycycline promoted HCC cell adhesion but inhibited HCC cell viability, proliferation, migration, and invasion. Western blot analysis, semiquantitative RT-PCR, qRT-PCR, and immunofluorescence demonstrated that doxycycline inhibited the degradation of the epithelial marker E-cadherin and downregulated the expression levels of EMT promoters, the mesenchymal marker vimentin, and the VM-associated marker vascular endothelial (VE)-cadherin. Furthermore, the activities of MMPs and DNMTs were examined in different groups via gelatin zymography and a DNMT activity assay kit. A methylation-specific PCR was performed to assess the promoter methylation of CDH1 (the gene encoding E-cadherin). Doxycycline prolonged the mouse survival time by inhibiting EMT progression and VM formation. Mol Cancer Ther; 13(12); 3107–22. ©2014 AACR.

Epithelial-to-endothelial transition and cancer stem cells: two cornerstones of vasculogenic mimicry in malignant tumors

Vasculogenic mimicry (VM) is a functional microcirculation pattern in malignant tumors accompanied by endothelium-dependent vessels and mosaic vessels. VM has been identified in more than 15 solid tumor types and is associated with poor differentiation, late clinical stage and poor prognosis. Classic anti-angiogenic agents do not target endothelium-dependent vessels and are not efficacious against tumors exhibiting VM. Further insight into the molecular signaling that triggers and promotes VM formation could improve anti-angiogenic therapeutics. Recent studies have shown that cancer stem cells (CSCs) and epithelium-to-endothelium transition (EET), a subtype of epithelial-to-mesenchymal transition (EMT), accelerate VM formation by stimulating tumor cell plasticity, remodeling the extracellular matrix (ECM) and connecting VM channels with host blood vessels. VM channel-lining cells originate from CSCs due to expression of EMT inducers such as Twist1, which promote EET and ECM remodeling. Hypoxia and high interstitial fluid pressure in the tumor microenvironment induce a specific type of cell death, linearly patterned programmed cell necrosis (LPPCN), which spatially guides VM and endothelium-dependent vessel networks. This review focuses on the roles of CSCs and EET in VM, and on possible novel anti-angiogenic strategies against alternative tumor vascularization.

Dickkopf-1-promoted vasculogenic mimicry in non-small cell lung cancer is associated with EMT and development of a cancer stem-like cell phenotype

To characterize the contributions of Dickkopf‐1 (DKK1) towards the induction of vasculogenic mimicry (VM) in non‐small cell lung cancer (NSCLC), we evaluated cohorts of primary tumours, performed in vitro functional studies and generated xenograft mouse models. Vasculogenic mimicry was observed in 28 of 205 NSCLC tumours, while DKK1 was detected in 133 cases. Notably, DKK1 was positively associated with VM. Statistical analysis showed that VM and DKK1 were both related to aggressive clinical course and thus were indicators of a poor prognosis. Moreover, expression of epithelial‐mesenchymal transition (EMT)‐related proteins (vimentin, Slug, and Twist), cancer stem‐like cell (CSC)‐related proteins (nestin and CD44), VM‐related proteins (MMP2, MMP9, and vascular endothelial‐cadherin), and β‐catenin‐nu were all elevated in VM‐positive and DKK1‐positive tumours, whereas the epithelial marker (E‐cadherin) was reduced in the VM‐positive and DKK1‐positive groups. Non‐small cell lung cancer cell lines with overexpressed or silenced DKK1 highlighted its role in the restoration of mesenchymal phenotypes and development of CSC characteristics. Moreover, DKK1 significantly promotes NSCLC tumour cells to migrate, invade and proliferate. In vivo animal studies demonstrated that DKK1 enhances the growth of transplanted human tumours cells, as well as increased VM formation, mesenthymal phenotypes and CSC properties. Our results suggest that DKK1 can promote VM formation via induction of the expression of EMT and CSC‐related proteins. As such, we feel that DKK1 may represent a novel target of NSCLC therapy.

Morphologic research of microcirculation patterns in human and animal melanoma

ObjectiveThe pattern and distribution of microcirculation of malignant melanoma were studied in human malignant melanoma tumor samples and in an animal model by staining of paraffin-embedded sections and transelectron microscopy.MethodsBlood supply models for melanoma were studied with immunohistochemical and periodic acid-Schiff (PAS) double-staining technique. New sections were made from 190 paraffin-embedded melanoma samples, and immunohistochemical staining of the platelet-endothelial cell adhesive molecule (CD31 antigen) and PAS staining were conducted to confirm different microcirculation patterns of melanoma Furthermore, malignant melanoma cells B16 and LiBr were injected into the groin of C57 mice and into the abdominal cavity of SCID mice, respectively. Tumors with vasculogenic mimicry (VM) were stained with PAS and CD31 to study the morphology and distribution of VM in mice melanoma. A diluted suspension of activated carbon was injected into the circulation of mice previously inoculated in the groin with B16 melanoma cells. Tumor tissue with VM was observed under electron microscopy.ResultsThere were three kinds of microcirculation pattern in human and animal melanoma. The walls of VM were positive for PAS staining and negative for CD31 staining in the tumor tissues. The distribution of VM and mosaic vessels was not uniform and appeared in patches. VM along with endothelium-dependent vessels and mosaic vessels sustained the blood supply for the tumors. The results from electron microscopy validated the presence of three patterns.ConclusionsThe results obtained using activated carbon as a tracer showed that VM and mosaic vessels connect with the host blood circulation. VM and mosaic vessels exist in malignant melanoma. Tumor cells can obtain oxygen and nutriment through VM and mosaic vessels besides endothelium-dependent vessels.