Introduction Of Tumor Cells Research Articles

Potential of 1.3-diethylbenzimidazolium triiodide in experimental therapy for lung cancer.

e15094 Background: The practice of thoracic oncology demonstrates that the lungs often become affected by cancer. The antitumor effect of chemoradiation therapy can be poor, and surgical treatment is associated with reduced functionality of the organ and therefore reduced quality of life of patients. Therefore, nonspecific agents are required that combine a pronounced antitumor effect and, at the same time, restore pulmonary tissue. Our purpose was to study the effects of 1,3-diethylbenzimidazolium triiodide in a rat model of lung cancer by morphological analysis of pulmonary tissues. Methods: An experimental model of lung cancer was created in 60 male and female rats by subclavian infusion of sarcoma 45 cell suspension in the saline at a dose of 0.5 ml (2×106). Iodine-containing preparation was administered enterally at 0.4 mg/kg daily for 5 days with a 2-day interval; treatment was started immediately after the intravenous injection of malignant cells, the therapy lasted for 8 weeks. The morphological control of the lungs was performed at decapitation of animals, tissue processing and staining, by light microscopy using the LEICA DM LS2 microscope with magnification of up to x100. Results: Hematogenous introduction of tumor cells into the lung caused hemorrhage, “acute swelling” of the alveoli, microabscesses, distelectasis, colonization of interalveolar septa with tumor cells and the formation of large metastatic foci. Involutive changes in the tumor tissue were noted together with signs of pulmonary regeneration: after 5 weeks of the treatment – pronounced activation of immune cells and occurrence of elastic fibers with reserve tortuosity; after 8 weeks - active proliferation of epithelial elements that form the bronchial-alveolar apparatus, an increase in surfactant activity in hypertrophied alveoli, and a significant strengthening of the elastic and collagen framework of the alveolar walls. Conclusions: Morphological correlates of the experimental effect of 1,3-diethylbenzimidazolium triiodide indicate its strong antitumor properties and potential for improving the recovery capabilities of the structure-forming elements of the lung.

Glioma C6 perivascular changes of invasion structural parameters variation (research study).

A comparative study of the structural characteristics of microvessels with a perivascular arrangement of tumor cells and microvessels with normal structure located in the peritumoral zones of an intracranially implanted glioblastoma ("glioma C6") was conducted. The study was performed on rats. Morphometric method was used to determine the area, internal diameter and length of microvessels for 21 days after the introduction of tumor cells into the brain of rats. Changes in the structure of microvessels with glioblastoma cells were registered throughout the entire observation period. The active role of perivascularly located tumor cells in the transformation of the structure and properties of microvessels involved in the process of glioblastoma invasion into brain tissue is considered.
 Key words: glioblastoma, microvessels, morphometry, peritumoral zones.

Abstract A19: Pulmonary microthrombosis enhances tumorigenesis via myeloid hypoxia-inducible factors

Abstract Thrombosis causes local blood flow restriction and tissue hypoxia, and both of these are associated with tumor cell metastasis. To better understand the regulation of thrombosis-induced metastasis, we created a model incorporating elements of both processes. Controlled induction of pulmonary microthrombosis caused an increase in expression of first hypoxia-inducible factor (HIF)1α, and subsequently HIF2α. Induction of thrombosis before the introduction of tumor cells to venous circulation had no effect on pulmonary tumor number or size; but thrombosis at the time of tumor cell seeding increased number and size of tumors in the lung. Thrombosis on the day after seeding of tumor cells caused an even greater increase in tumor number and size, and this effect persisted until even when thrombosis was induced five days after the introduction of tumor cells into the blood. Experiments on myeloid HIF1α or HIF2α knockout mice demonstrated that loss of either HIF1α or HIF2α eliminated the advantage given to pulmonary tumorigenesis by thrombotic insult. In primary human tumours, markers of thrombosis were positively correlated with expression of the 2 HIFα isoforms. These data demonstrate the importance of microthrombosis in a novel model of metastasis and the essential role of the myeloid cell-specific HIFα response in mediating this process. Citation Format: Colin E. Evans, Asis Palazon, Jingwei Sim, Petros A. Tyrakis, Par-Ola Bendahl, Mattias Belting, Helene Rundqvist, Cristina Branco, Randall S. Johnson. Pulmonary microthrombosis enhances tumorigenesis via myeloid hypoxia-inducible factors. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr A19.

Abstract 2824: In vitro tumor extravasation model.

Abstract Cancer cell metastasis is a series of biological processes that allow malignant tumor cells to invade from primary to secondary sites. Understanding the invasion of the secondary site remote tissue requires studying the individual steps in metastasis, particularly, those leading up to and immediately following extravasation of a circulating tumor cell from a blood vessel into the remote tissue. The platform presented here mimics the tumor microenvironment in a well-controlled manner, and provides high resolution imaging of tumor cell extravasation and the early stages of colonization. We investigate the extravasation step where tumor cells transmigrate across an endothelial monolayer into a hydrogel model of the extracellular space. We find tumor cells are more likely to extravasate soon after contact with the endothelium. We have cultured and sustained an endothelial monolayer spanning the entire microchannel and hydrogel surface of the microfluidic system. Two days after seeding of endothelial cells, we introduced tumor cells into the same microchannel now covered with endothelium to observe cancer cell extravasation. The experimental protocol is optimized to ensure the formation of an intact endothelium prior to the introduction of tumor cells and also to observe tumor cell extravasation by having a suitable tumor seeding density. Extravasation is observed for 35% of the tumor cells in contact with the endothelium within 1 day after their introduction. The region of interest (ROI) is imaged with confocal microscopy and can determine whether a cancer cell, labeled green with GFP, has transmigrated across the endothelium, denoted by VE-cadherin staining, and extravasated into the gel region. We also measured the permeability of the endothelial monolayer to monitor barrier integrity as well as the changes induced by interactions with tumor cells by measuring the diffusion of fluorescently-labeled dextran across the monolayer. Permeability increased 3.8 fold 24 hours after introducing tumor cells, suggesting the endothelial barrier integrity is compromised by the interactions. Average number of tumor cells in ROIs increased between day 1 and day 3 after tumor seeding while the percent of ROIs with extravasated cells did not change significantly. These results suggest that extravasation in our system occurs predominantly within the first 24 hours of tumor cell introduction and that proliferation can continue both prior to and after extravasation. The experimental systems have a major advantage in studying cancer extravasation; they can mimic aspects of the 3D in vivo situation in a controlled environment while simultaneously providing in situ imaging capabilities for visualization. Thus, this model allows quantitative study of metastatic cancer interactions with the potential to identify novel metrics of cancer cell invasiveness and suggests possible use as a platform for drug screening. Citation Format: Jessie S. Jeon, Ioannis K. Zervantonakis, Seok Chung, Joseph Charest, Roger D. Kamm. In vitro tumor extravasation model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2824. doi:10.1158/1538-7445.AM2013-2824

Activation of omental immune aggregates: a potential tumor therapy (131.37)

Abstract Tumor metastasis within the peritoneal cavity is a concern for those diagnosed with cancers of peritoneal organs. A tissue implicated in this process is the omentum, which is composed of adipose tissue embedded with immune cell aggregates. We, and others have demonstrated that upon introduction of tumor cells into the peritoneal cavity, omental immune aggregates are the initial site of attachment. Due to their high vascularity, they provide an ideal microenvironment for tumor growth. Thus, treatment of peritoneal metastases often includes removal of the omentum. However, we hypothesize that stimulation of omental immune cells might result in reduced tumor growth. Our initial experiments demonstrate that injection of particles into the peritoneal cavity resulted in their uptake by macrophages present in the peritoneal fluid and rapid migration to immune aggregates. To determine if tumor antigens would result in effective immunity when bound to these aggregates, mice were immunized intraperitoneally with irradiated EMT6 tumor cells and later challenged with live EMT6/GFP cells. Omenta and peritoneal fluid were analyzed for the presence of memory CD8+ T cells and tumor cells. Our results show that immunization results in increased memory CD8+ T cells and decreased tumor burden on the omentum, indicating that omental immune cells are capable of responding against tumor cells. Further studies are being done to examine tumor burden in mice immunized after tumor establishment.

Treatment with allogeneic interleukin-2 secreting fibroblasts protects against the development of malignant brain tumors.

We have reported that mice with an intracerebral (i.c.) malignant glioma or breast cancer treated with i.c. injection of allogeneic fibroblasts genetically engineered to secrete interleukin-2 (IL-2) survived longer than mice in various control groups. The goal of the present study was to determine the effectiveness of utilizing IL-2 secreting allogeneic fibroblasts as a protective treatment to prevent the development of an i.c. glioma or breast carcinoma. Using an intracranial microcannula system that we developed, the animals received weekly injections of the cellular vaccine prior to the introduction of tumor cells via the cannula. The results demonstrate a significant delay (P < 0.005) in the development of glioma in the animals pre-treated with either allogeneic non-secreting or IL-2-secreting fibroblasts prior to introduction of tumor cells. In addition, 50% of the animals pre-treated with IL-2 secreting allogeneic fibroblasts injected subsequently with G1261 glioma cells did not develop a tumor, while all of the animals injected with glioma cells alone and 92% of those treated with non-secreting fibroblasts eventually died. The long-term survivors from the pre-treatment group were subsequently re-challenged with tumor and compared to naive controls. There was evidence that long-term immunity was established in the pre-treated animals, since there was a significant prolongation of survival (P < 0.01). In similar experiments using breast cancer cells, 62% of the animals pre-treated with non-secreting allogeneic fibroblasts and 75% of the animals pre-treated with allogeneic IL-2 secreting fibroblasts subsequently injected with SB-5b breast carcinoma cells did not develop tumors and had a significant prolongation of survival. These data suggest that i.c. injection of allogeneic IL-2 secreting fibroblasts are effective as a protective treatment in the prevention of the development of a brain tumor when the fibroblasts are introduced into the same site where the tumor is subsequently injected.