Jiadong Chi

Slug promoted vasculogenic mimicry in hepatocellular carcinoma.

Vasculogenic mimicry (VM) refers to the unique capability of aggressive tumour cells to mimic the pattern of embryonic vasculogenic networks. Epithelial–mesenchymal transition (EMT) regulator slug have been implicated in the tumour invasion and metastasis of human hepatocellular carcinoma (HCC). However, the relationship between slug and VM formation is not clear. In the study, we demonstrated that slug expression was associated with EMT and cancer stem cell (CSCs) phenotype in HCC patients. Importantly, slug showed statistically correlation with VM formation. We consistently demonstrated that an overexpression of slug in HCC cells significantly increased CSCs subpopulation that was obvious by the increased clone forming efficiency in soft agar and by flowcytometry analysis. Meantime, the VM formation and VM mediator overexpression were also induced by slug induction. Finally, slug overexpression lead to the maintenance of CSCs phenotype and VM formation was demonstrated in vivo. Therefore, the results of this study indicate that slug induced the increase and maintenance of CSCs subpopulation and contributed to VM formation eventually. The related molecular pathways may be used as novel therapeutic targets for the inhibition of HCC angiogenesis and metastasis.

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.

Clinical significances and prognostic value of cancer stem-like cells markers and vasculogenic mimicry in renal cell carcinoma

The aim of this study was to investigate the clinical significances and prognostic value of CD133 and CD44 (markers of cancer stem‐like cells, CSCs), and vasculogenic mimicry (VM) in renal cell carcinoma (RCC).

HER2/neu expression correlates with vasculogenic mimicry in invasive breast carcinoma.

Vasculogenic mimicry (VM) refers to the condition in which tumour cells mimic endothelial cells to form extracellular matrix‐rich tubular channels. VM is more extensive in more aggressive tumours. The human epidermal growth factor receptor 2 (HER2) gene is amplified in 20–30% of human breast cancers and has been implicated in mediating aggressive tumour growth and metastasis. However, thus far, there have been no data on the role of HER2 in VM formation. Immunohistochemical and histochemical double‐staining methods were performed to display VM in breast cancer specimens. Transfection in MCF7 cells was performed and clones were selected by G418. The three‐dimensional Matrigel culture was used to evaluate VM formation in the breast cancer cell line. According to statistical analysis, VM was related to the presence of a positive nodal status and advanced clinical stage. The positive rate of VM increased with increased HER2 expression. In addition, cases with HER2 3+ expression showed significantly greater VM channel count than those in other cases. The exogenous HER2 overexpression in MCF‐7 cells induced vessel‐like VM structures on the Matrigel and increased the VM mediator vascular endothelial (VE) cadherin. Our data provide evidence for a clinically relevant association between HER2 and VM in human invasive breast cancer. HER2 overexpression possibly induces VM through the up‐regulation of VE cadherin. Understanding the key molecular events may provide therapeutic intervention strategies for HER2+ breast cancer.

The in-vitro spheroid culture induces a more highly differentiated but tumorigenic population from melanoma cell lines.

Cancer stem cells (CSCs) have been identified in various malignancies, and different properties have been examined to characterize CSCs: tumorigenicity in immunocompromised mice, stem cell surface markers, label-retaining properties, and proliferation as nonadherent spheres. This study explored the consistency and efficiency among these methods. Among the melanoma cell lines examined (A375, A875, MUM-2b, and MUM-2c), only A375 and MUM-2c grew as nonadherent spheres and continuously propagated in a defined serum-free medium in vitro. Flow cytometry and immunofluorescence analysis indicated that sphere-derived cells contained a smaller proportion of cells expressing the candidate surface markers of melanoma stem cells such as ABCB5, CD133, CD20 and CD271, and a larger proportion of cells expressing melanocytic differentiation markers such as HMB45 and S100 protein, compared with adherent cells. Surprisingly, the more highly differentiated sphere-derived melanoma cells exhibited increased tumorigenic potential in vivo, as indicated by shorter tumor incubation (A375) and smaller number of cells required to initiate tumor formation (A375 and MUM-2c) compared with those of parental cells. Despite the similarity in histopathological characteristics, the expression profile indicated that xenografts derived from sphere-derived melanoma cells exhibited a more tumorigenic phenotype with respect to the stem or the differentiation markers detected by immunohistochemical analysis. Therefore, sphere formation in nonadherent cultures may not be a preferred surrogate in-vitro method for enriching melanoma stem cells according to candidate markers but may be a favorable condition for activating potential CSCs.

Hypoxia-induced senescence contributes to the regulation of microenvironment in melanomas.

Senescence, an irreversible state of cell cycle arrest, maintains metabolic activity. Although being a barrier against tumor development, senescence could also promote tumor progression by influencing the microenvironment. Necrosis is a common feature of various malignant tumors, which also has two opposing effects: pro-tumor by chronic inflammation and anti-tumor by effective cell clearance. However, the role of senescence in melanoma and whether it is associated with necrosis remain unclear. By detecting senescence-associated β-galactosidase activity and pimonidazole (hypoxia probe), we found that senescent cells (SA-β-gal positive) are mainly located around the necrotic/hypoxic areas of melanoma from C57BL/6J mice. Moreover, treatment of hypoxia induced irreversibly cellular senescence in vitro. In addition, the senescent cells may facilitate microenvironment modulation and promote the invasion of melanoma cells by secreting matrix metalloproteinase-2(MMP-2). Moreover, Kaplan-Meier analysis showed that the presence of necrosis in melanomas had an inverse correlation with patient survival and may serve as an independent prognostic marker. Therefore, hypoxic stress imposed on melanomas may lead to cellular senescence surrounding necrotic areas, and the adverse effects of necrosis in tumor may be attributed to the adjacent senescent cells with senescence-associated secretion phenotype (SASP), including secretion of MMP-2.

Secreted CLU is associated with the initiation of triple-negative breast cancer

Triple-negative breast cancer, which is negative for the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, represents about 15–26% of all breast cancer cases. However, because of its genotype, a triple-negative disease accounts for a remarkable metastasis and mortality. Moreover, no targeted treatment is available because the molecular mechanism of triple-negative breast cancer initiation is still unclear. Secreted clusterin (sCLU) is associated with the refractory to anti-estrogen in breast cancer cells. We investigated the sCLU expression in 384 human breast cancer cases, including 61 triple-negative cases, as well as the relationship between sCLU and clinical pathological characteristics. Triple-negative patients (75.4%) were positive for sCLU based on immunohistochemical analysis, and sCLU expression in this subtype was proven related to a larger tumor size, an axillary node status, and a higher clinical stage. Furthermore, we used a spontaneous breast cancer mouse strain with a triple-negative genotype to detect the sCLU dynamic expression in breast cancer oncogenesis using western blot and real-time polymerase chain reaction. The sCLU mRNA and protein expression in the tumor and hyperplastic epithelium were upregulated and reached a peak compared with those of a normal mammary gland. These results suggest that sCLU is involved in the initiation of triple-negative breast cancer, which is beneficial for the clinical trial design of an anti-CLU treatment for triple-negative breast cancer.

Aurora-A-mediated phosphorylation of LKB1 compromises LKB1/AMPK signaling axis to facilitate NSCLC growth and migration

Deletion or loss-of-function mutation of LKB1, frequently occurring in non-small cell lung cancers (NSCLCs), is a predominant caution of NSCLC initiation and progression. However, the upstream signaling pathways governing LKB1 activation are largely unknown. Here, we report that LKB1 undergoes Aurora kinase A (AURKA)-mediated phosphorylation, which largely compromises the LKB1/AMPK signaling axis, in turn leading to the elevation of NSCLC cell proliferation, invasion and migration. Mechanically, AURKA-mediated phosphorylation of LKB1 impairs LKB1 interaction with and phosphorylation of its downstream target AMPKα, which has critical roles in governing cancer cell energy metabolic homeostasis and tumorigenesis. Clinically, AURKA displays high levels in NSCLC patients, and correlates with poor outcome of patients with lung adenocarcinoma. Pathologically, the amplification or activation of AURKA-induced impairment of the LKB1/AMPK signaling pathway contributes to NSCLC initiation and progression, highlighting AURKA as a potential therapeutic target for combatting hyperactive AURKA-driven NSCLCs.

Expression of relative-protein of hypoxia-inducible factor-1α in vasculogenesis of mouse embryo

BackgroundPhysiological vasculogenesis in embryonic tissues share some important features with pathological neoangiogenesis in tumors. Linearly Patterned Programmed Cell Necrosis (LPPCN) and Vasculogenic Mimicry (VM) have been reported in tumors. The term VM refers to the aggressive tumor cells with CD31-negative phenotype to form Periodic Αcid Schiff (PAS)-positive network, that mimics the pattern of embryonic vasculogenic networks. LPPCN had been observed in our laboratory, and served as a spatial infrastructure for VM and endothelium-dependent vessel formation. Studies have been shown that hypoxia-inducible factor-1α (HIF-1α) can induce tumor cells to form vessel-like tubes and express genes associated with VM. Therefore, an analogous investigation has been carried out to determine if these patterns existed in mouse embryonic vasculogenesis.ResultsIn this essay, the results demonstrated that the number of Linearly Patterned Cell Αpoptosis (LPCA), embryo Vasculogenic Μimicry (embryo VM), endothelium-dependent vessels, and relative-protein of HIF-1α expression all showed time-dependent tendencies on E5.5-E9.5 (p < 0.05). The proteins CD133, VEGF, Twist, E-cadherin, and Vimentin showed local plexus distribution on E6.5-E7.5 (p < 0.05).ConclusionsLPCA and embryo VM existed in embryonic vasculogenesis. The relative protein of HIF-1α regulated the mouse embryonic vasculogenesis.