Vasculogenic mimicry plays an important role in adrenocortical carcinoma

Unveiling the experimental proof of the anticancer potential of ginsenoside Rg3 (Review)

Ginsenoside Rg3 (GS-Rg3), a sterol molecule isolated from ginseng, has demonstrated various immunological properties, including inhibition of cancer cell proliferation and metastasis, reversal of drug resistance and enhancement of chemotherapy sensitivity. The recent surge in attention towards GS-Rg3 can be attributed to its potential as an antitumor angiogenesis agent and as a therapeutic candidate for immunotherapy. The development of GS-Rg3 as an agent for these purposes has accelerated research on its mechanisms of action. The present review summarizes recent studies investigating the antitumor activity of GS-Rg3 and its underlying mechanisms, as well as providing essential information for future studies on GS-Rg3.

Self-anti-angiogenesis nanoparticles enhance anti-metastatic-tumor efficacy of chemotherapeutics

Beyond traditional endothelium-dependent vessel (EDV), vascular mimicry (VM) is another critical tumor angiogenesis that further forms in many malignant metastatic tumors. However, the existing anti-angiogenesis combined chemotherapeutics strategies are only efficient for the treatment of EDV-based subcutaneous tumors, but remain a great challenge for the treatment of in situ malignant metastatic tumor associated with EDV and VM. Here, we demonstrate a self-assembled nanoparticle (VE-DDP-Pro) featuring self-anti-EDV and -VM capacity enables to significantly enhance the treatment efficacy of cisplatin (DDP) against the growth and metastasis of ovarian cancer. The VE-DDP-Pro is constructed by patching DDP loaded cRGD-folate-heparin nanoparticles (VE) onto the surface of protamine (Pro) nanoparticle. We demonstrated the self-anti-angiogenesis capacity of VE-DDP-Pro was attributed to VE, which could significantly inhibit the formation of EDV and VM by regulating signaling pathway of MMP-2/VEGF, AKT/mTOR/MMP-2/Laminin and AKT/mTOR/EMT, facilitating chemotherapeutics to effectively suppress the development and metastasis of ovarian cancer. Thus, combing with the chemotherapeutics effectiveness of DDP, the VE-DDP-Pro can significantly enhance treatment efficacy and prolong median survival of mice with metastatic ovarian cancer. We believe our self-assembled nanoparticles integrating the anti-EDV and anti-VM capacity provide a new preclinical sight to enhance the efficacy of chemotherapeutics for the treatment malignant metastasis tumor.

Three Dimensional Cell Culturing for Modeling Adrenal and Pituitary Tumors

In vitro monolayer conditions are not able to reproduce the complexity of solid tumors, still, there is scarce information about the 3D cell culture models of endocrine tumor types. Therefore, our aim was to develop in vitro 3D tumor models by different methodologies for adrenocortical carcinoma (H295R), pituitary neuroendocrine tumor (RC-4B/C and GH3) and pheochromocytoma (PC-12). Various methodologies were tested. Cell biological assays (cell viability, proliferation and live cell ratio) and steroid hormone production by HPLC-MS/MS method were applied to monitor cellular well-being. Cells in hanging drops and embedded in matrigel formed multicellular aggregates but they were difficult to handle and propagate for further experiments. The most widely used methods: ultra-low attachment plate (ULA) and spheroid inducing media (SFDM) were not the most viable 3D model of RC-4B/C and GH3 cells that would be suitable for further experiments. Combining spheroid generation with matrigel scaffold H295R 3D models were viable for 7 days, RC-4B/C and GH3 3D models for 7–10 days. ULA and SFDM 3D models of PC-12 cells could be used for further experiments up to 4 days. Higher steroid production in 3D models compared to conventional monolayer culture was detected. Endocrine tumor cells require extracellular matrix as scaffold for viable 3D models that can be one reason behind the lack of the usage of endocrine 3D cultures. Our models help understanding the pathogenesis of endocrine tumors and revealing potential biomarkers and therapeutic targets. They could also serve as an excellent platform for preclinical drug test screening.

Fact or Fiction, It Is Time for a Verdict on Vasculogenic Mimicry?

The term vasculogenic mimicry (VM) refers to the capacity of certain cancer cells to form fluid-conducting structures within a tumor in an endothelial cell (EC)-free manner. Ever since its first report by Maniotis in 1999, the existence of VM has been an extremely contentious issue. The overwhelming consensus of the literature suggests that VM is frequently observed in highly aggressive tumors and correlates to lower patient survival. While the presence of VM in vivo in animal and patient tumors are claimed upon the strong positive staining for glycoproteins (Periodic Acid Schiff, PAS), it is by no means universally accepted. More controversial still is the existence of an in vitro model of VM that principally divides the scientific community. Original reports demonstrated that channels or tubes occur in cancer cell monolayers in vitro when cultured in matrigel and that these structures may support fluid movement. However, several years later many papers emerged stating that connections formed between cancer cells grown on matrigel represented VM. We speculate that this became accepted by the cancer research community and now the vast majority of the scientific literature reports both presence and mechanisms of VM based on intercellular connections, not the presence of fluid conducting tubes. In this opinion paper, we call upon evidence from an exhaustive review of the literature and original data to argue that the majority of in vitro studies presented as VM do not correspond to this phenomenon. Furthermore, we raise doubts on the validity of concluding the presence of VM in patient samples and animal models based solely on the presence of PAS+ staining. We outline the requirement for new biomarkers of VM and present criteria by which VM should be defined in vitro and in vivo.

TM4SF5 promotes metastatic behavior of cells in 3D extracellular matrix gels by reducing dependency on environmental cues

Transmembrane 4 L six family member 5 (TM4SF5) is highly expressed in hepatocellular carcinoma tissues and enhances migration in two-dimensional environments. Here, we investigated how TM4SF5 is involved in diverse pro-metastatic phenotypes in in vivo-like three-dimensional (3D) extracellular matrix gels. TM4SF5-positive cells aggressively formed invasive foci in 3D Matrigel, depending on TM4SF5-mediated signaling activity, cytoskeletal organization, and matrix metallopeptidase (MMP) 2-mediated extracellular remodeling, whereas TM4SF5-null cells did not. The TM4SF5-null cells did, however, form invasive foci in 3D Matrigel following inhibition of Rho-associated protein kinase or addition of collagen I, suggesting that collagen I compensated for TM4SF5 expression. Similarly, TM4SF5-positive cells expressing vascular endothelial-cadherin formed network-like vasculogenic mimicry in 3D Matrigel and collagen I mixture gels, whereas TM4SF5-negative cells in the mixture gels displayed the network structures only upon further treatment with epidermal growth factor. The foci formation also required MMP2-mediated remodeling of the extracellular matrix. Co-cultures exhibited TM4SF5-positive or cancer-associated fibroblasts at the outward edges of TM4SF5-null cell clusters. Compared with TM4SF5-null cells, TM4SF5-positive cells in 3D collagen gels showed a more invasive outgrowth with dramatic invadopodia. These observations suggest that TM4SF5 plays roles in the promotion of diverse metastatic properties with fewer environmental requirements than TM4SF5-negative cells.