Overexpression of HIF-1α in primary gallbladder carcinoma and its relation to vasculogenic mimicry and unfavourable prognosis

Abstract

Abstract.As a novel mode of tumor neovascularization, vasculogenic mimicry (VM) has been reported to increase tumor-related mortality in many different solid tumors. In the present study, two established human gallbladder carcinoma (GBC) cell lines (highly aggressive GBC-SD and poorly aggressive SGC-996) cultured on a three-dimensional matrix were assessed for the ability of VM channel formation under normoxic or hypoxic conditions. In addition, the relationship between HIF-1α gene expression and VM channel formation of GBC cells in vitro was measured using the small interfering RNA (siRNA) technique, western blotting and real-time reverse transcription (RT)-PCR analysis. Furthermore, H&E and CD31/periodic acid-Schiff (PAS) staining were used to observe VM in GBC tissue samples. Additionally, all seventy-one specimens with VM and non-VM were stained for hypoxia inducible factor-1 α (HIF-1α) and its correlation with clinicopathological features and prognosis was analyzed simultaneously. We found that hypoxia could induce more VM channel formation and elevated HIF-1α expression in highly aggressive GBC-SD cells. HIF-1α siRNA efficiently knocked down HIF-1α expression and GBC VM networks under either normoxic or hypoxic conditions. VM was present in human primary GBC and overexpression of HIF-1α was significantly correlated with depth of invasion and perineural involvement in the non-VM group. Moreover, VM and HIF-1α were independent factors for the overall survival of GBC patients and correlated with decreased survival. In conclusion, VM was present in human GBC. As a critical mediator in VM formation, high expression of HIF-1α was associated with VM and tumor progression in GBC patients.

Inhibition of Tumor Vasculogenic Mimicry and Prolongation of Host Survival in Highly Aggressive Gallbladder Cancers by Norcantharidin via Blocking the Ephrin Type a Receptor 2/Focal Adhesion Kinase/Paxillin Signaling Pathway

“…VM is a newly-defined tumor microcirculation pattern in some highly aggressive malignant tumors, which differs from endothelium-dependent angiogenesis, and is associated with a poor prognosis for the patients with some aggressive malignancies such as melanoma and gallbladder cancers [11], [14]–[18]. Because VM is an alternative pathway for highly aggressive tumors to guarantee their blood supply, whereas not an angiogenic event arising from pre-existing vessels, it is necessary to find potential therapeutic approaches for targeting VM or in addition to antiangiogenic therapies [23]–[25].…”

“…Because VM is an alternative pathway for highly aggressive tumors to guarantee their blood supply, whereas not an angiogenic event arising from pre-existing vessels, it is necessary to find potential therapeutic approaches for targeting VM or in addition to antiangiogenic therapies [23]–[25]. We reported that VM existed in human gallbladder cancers, highly aggressive gallbladder cancer GBC-SD cells and xenografts; whereas poorly aggressive SGC-996 cells did not form the VM networks under the same conditions [13], [17], [18], [42]. In this study, the results showed that NCTD, similar to TIMP-2, inhibited tumor growth and VM formation of GBC-SD xenografts, and prolonged survival time of the xenograft mice.…”

“…In histology, VM emerges as multiple, ECM-rich networks surrounding clusters of tumor cells, which can be stained with periodic acid-Schiff (PAS) [11]. VM or a PAS-positive pattern is associated with tumor aggressiveness, poor clinical outcome, and high risk of recurrence in patients with melanoma [11], [14]–[16], gallbladder cancer [17], [18], and other malignances [19]–[22]. Because the formation of VM channels is not an angiogenic event as it does not arise from pre-existing vessels, this angiogenesis-independent fact could explain why antiangiogenic therapies have clinically failed in some tumors, specially highly aggressive tumors e.g.…”

“…However the exact mechanism responsible for the NCTD antitumor is not thoroughly elucidated. We recently reported that VM existed in human gallbladder cancers and gallbladder cancers by both 3-D matrix of highly aggressive GBC-SD cells in vitro and GBC-SD nude mouse xenografts in vivo and correlated with the patient's poor prognosis and that poorly aggressive SGC-996 cells did not form the vasculogenic-like networks when cultured under the same conditions [12], [13], [17], [18]. We identified that VM formation in gallbladder cancers through the activation of a key VM-related signaling pathway—the EphA2/FAK/Paxillin signaling pathway in the 3-D matrix of highly aggressive GBC-SD cells in vitro and GBC-SD nude mouse xenografts in vivo [42].…”

Osteopontin as a Key Mediator for Vasculogenic Mimicry in Hepatocellular Carcinoma

“…VM describes the unique ability of highly aggressive tumor cells, but not poorly aggressive tumor cells, to form matrixrich networks de novo when cultured on a three-dimensional matrix, thus mimicking embryonic vasculogenesis (Maniotis et al 1999). VM, advanced by Maniotis et al (1999), has been described in several other aggressive tumor types, including gallbladder carcinoma (Fan et al 2007), breast cancer (Basu et al 2006), prostate cancer (Sood et al 2001), ovarian carcinoma (Heyman et al 2010), colorectal cancer (Baeten et al 2009), clear cell renal cell carcinoma (Vartanian et al 2009), and acute leukemic bone marrow stromal cells (Mirshahi et al 2009). In recent years, we and others have described the presence of VM in human HCC samples and initiatively investigated its clinical significance (Sun et al 2006;Sun et al 2010;Liu et al 2010).…”