Vascular endothelial growth factor secretion by tumor-infiltrating macrophages essentially supports tumor angiogenesis, and IgG immune complexes potentiate the process.

Tumor growth requires neoangiogenesis. Members of the vascular endothelial growth factor (VEGF) family play an important role as angiogenic promoters in malignant tumors. Tumor cells and stromal cells are sources of VEGF in the tumor.

IgG-recognizing shed tumor-associated antigens can promote tumor invasion and metastasis.

Tumors secreting glycoproteins that act as tumor-associated antigens have been described as highly invasive and metastatic. In this study, the consequences of the humoral immune response (HIR) against these antigens were investigated. Using an in vitro model of tumor cell invasion, results indicated that the invasiveness of tumor cells secreting antigenic secreted/shed tumor glycoproteins (STGP) increases in the presence of specific anti-STGP IgG, polymorphonuclear cells and monocytes.

Tumor cells express FcgammaRI which contributes to tumor cell growth and a metastatic phenotype.

High levels of circulating immune complexes containing tumor-associated antigens are associated with a poor prognosis for individuals with cancer. The ability of B cells, previously exposed to tumor-associated antigens, to promote both in vitro and in vivo tumor growth formed the rationale to evaluate the mechanism by which immune complexes may promote tumor growth. In elucidating this mechanism, FcgammaRI expression by tumor cells was characterized by flow cytometry, polymerase chain reaction, and sequence analysis.

Direct in vivo transfection of antisense Fas-ligand reduces tumor growth and invasion.

The expression of Fas ligand (FasL) by tumor cells has been reported to have multiple, conflicting effects on tumor growth. The majority of the data support the theory that FasL expressing tumor cells evade immune surveillance by killing T cells expressing Fas. However, the role of the humoral immune-blockade by FasL expressing tumor cells has not been assessed.

Promotion of tumor invasion by cooperation of granulocytes and macrophages activated by anti-tumor antibodies.

We investigated the potential role of anti-tumor antibodies and tumor antigens in the formation of immune complexes which promote matrix degradation and angiogenesis. B-cell deficient or B-cell depleted mice showed a reduction in tumor invasion and metastasis. In vitro invasion assays and in vivo models of metastasis showed that anti-sTn antibodies and sTn tumor antigens form complexes which induce granulocytes and macrophages together to mediate tumor invasion and metastasis by processes including extracellular matrix degradation and angiogenesis.

Radioimmunoguided Surgery for Gastrointestinal Malignancies: An Analysis of 14 Years of Clinical Experience.

BACKGROUND: The identification of all sites of intra-abdominal adenocarcinoma is key to optimal surgical resection and tumor staging. Conventional imaging methods and direct visualization and palpation have limited sensitivity and specificity. Radioimmunoguided surgery (RIGS) has a potential to improve these parameters.

B lymphocyte pathology in human colorectal cancer. Experimental and clinical therapeutic effects of partial B cell depletion.

Accumulating data are showing that the humoral immune response against tumors could favor tumor progression. However, no B lymphocyte pathology has been reported in cancer. Using anti-IgM Ab we nonspecifically depleted B cells in tumor-bearing mice, a treatment that resulted in significant reduction of tumor burden.

Staging of colorectal cancer: biology vs. morphology.

Purpose: An accurate determination of the extent or staging of a disease is critical, because it provides the basis for making therapeutic decisions. Staging is a collaborative effort by the surgeon and the pathologist. Radioimmunoguided surgery has been evaluated for its ability to help surgeons determine the extent of disease during surgery, when management decisions have the most impact on patient care.

First results for resetting the antitumor immune response by immune corrective surgery in colon cancer.

Background: A critical step for cancer recurrence is the failure of the cellular immune response. It is suspected that chronic humoral immune responses against some tumor-associated antigens (TAA) can contribute to that failure.

Methods: In this study, we tested the ability of an immune corrective surgical procedure to prevent recurrences of colon cancer in stages I, II, and III.

[Lymphadenectomy in colorectal carcinoma].

Recurrence of colorectal carcinomas occurs in about 50% of the cases with localized neoplasia. It is understood that the tumor recurrence is due to residual micrometastases not found during surgery or extraregional (peripheral blood or bone marrow). We developed a procedure to detect non-visible, abdominal metastases using a radiolabeled anti-tumor cell antibody injected before the operation (radioimmunoguided surgery RIGS).

Extramedullary hematopoiesis in the adult mouse liver is associated with specific hepatic sinusoidal endothelial cells.

In previous work, two anatomically distinct-liver sinusoid endothelial cells (LEC): LEC-1 and LEC-2, have been described. We also reported that extramedullary hepatic hematopoiesis occurs only in close contact with LEC-1, suggesting that these cells may provide the microenvironment necessary for the maintenance and growth of hematopoietic cells. In the present work, we studied the capacity of LEC-1 and LEC-2 to maintain in vitro hematopoiesis.

Automated imaging and quantitation of tumor cells and CFU-GM colonies in microcapillary cultures: toward therapeutic index-based drug screening.

Human colony forming units (CFUs) from both malignant and hematopoietic tissues can be assayed in vitro in microcapillary cultures, an alternative cloning system to the Petri dish methodology. For technical reasons, microcapillary culture may be ideally suited for new drug screening by therapeutic index. To achieve the high output required by screening programs, automated quantitation of CFUs is required.

Tumor-host interaction in non-random metastatic pattern distribution.

In the clinical evolution of malign tumors, prognosis depends on whether metastasis develops or not. Biologically speaking, the formation of metastasis implies the existence of tumor cells capable of successfully performing all the steps in the metastatic process: local invasion, lymphatic or hematogenous dissemination, arrest in the microvascular bed of an organ, extravasation and growth of a secondary colony. Clinical observations have demonstrated that for each primary tumor there is a colonization pattern determined by the characteristics of the microvascular endothelium and the functional environment of the target organ.

The addition of interleukin-2 to cyclophosphamide therapy can facilitate tumor growth of B16 melanoma.

The role of interleukin-2 (IL-2) on tumor growth of B16F10 melanoma cells was assessed in two sets of mice with different immune status: normal (immunocompetent) mice and immunodeficient mice. The two sets of animals were treated with cyclophosphamide (CY) or IL-2 alone or with a combined therapy of CY+IL-2. On days 6 and 10 after tumor cell injection, we evaluated the incidence of hepatic B16 melanoma metastases and the percentage of hepatic volume occupied by metastatic tissue.

A simple cell labeling technique by means of lectins linked to fluorochromes for the detection of cells on tissue sections.

We designed a protocol for cell labeling with the lectin wheat germ agglutinin (WGA) linked to the fluorochrome tetramethyl-rhodamine isothiocyanate (TRITC) for effective detection of the B16F10 melanoma and Lewis lung carcinoma (LLc) cells on pulmonary histological sections from C57BL/6 mice. We have also determined a suitable concentration of WGA-TRITC (10 micrograms/ml), which leads to a very intense and homogeneous labeling of the cells, as it avoids cell clumping due to the presence of the lectin WGA. In order to determine to what extent the method affects these tumor cells, we have studied some important aspects related to their metastatic behavior, taking into account three parameters: a) viability and rate of proliferation of the cells cultured in vitro; b) percentage of animals (C57BL/6 mice) bearing metastasis 15 days after intravenous inoculation with 10(5) B16F10 or LLc cells; and c) pattern of distribution of tumor foci in lung.

Tissue distribution and therapeutic effect of intravenous free or encapsulated liposomal doxorubicin on human prostate carcinoma xenografts.

Background: The authors compared the therapeutic effects of doxorubicin in two formulations: free in saline suspension and encapsulated in sterically stabilized liposomes composed of hydrogenated soy phosphatidylcholine/2cholesterol/polyethylene glycol-distearoyl-phosphatidyl-ethanolamine (Doxil, Liposome Technology, Inc., Menlo Park, CA).

Method: The drug formulations were injected intravenously to treat human prostate carcinoma PC-3, implanted subcutaneously into nude Swiss mice.

Enhancement of Ia antigen expression and nonproliferating cells correlates with metastatic capacity.

Maintaining B16F10 tumor cells in stirring culture for 48 h leads to an increase in lung and liver colonizing capacity in comparison with cells in adherent culture. Parallel to the increased metastatic capacity, we have observed a decrease in the proliferative rate of tumor cells (as the percentage of proliferating cell nuclear antigen-positive cells) and an increase in the population of tumor cells expressing Ia antigen. These results are not exclusive to B16F10 cells, since the same results were obtained when we analyzed 3LL cells maintained in identical culture conditions.

Isolation and enrichment of two sublobular compartment-specific endothelial cell subpopulations from liver sinusoids.

Similar to the well-recognized phenotypical heterogeneity of hepatocytes, in situ sublobular variations have recently been detected in the cell structure, fenestration patterns, filtrating efficiency, surface glycosylation, scavenger function and pathological responses of the sinusoidal lining endothelium. However, unlike other liver cell populations, until now no endothelial cell subpopulations had been isolated or defined with clarity, much less with sublobular/acinar zone-related differential properties. On the basis of our previous studies showing that periportal segments of mouse liver sinusoids express a significantly higher number of wheat germ agglutinin-binding sites than do perivenous ones, we used this differential feature for in vitro labeling of the specific sublobular derivation of isolated sinusoidal lining endothelial cells to correlate their original lobular position with other features determined on flow cytometry, centrifugal elutriation, discontinuous arabinogalactan density gradients and electron microscopy.

Cancer-cell traffic in the liver. III Lethal deformation of B16 melanoma cells in liver sinusoids.

It has previously been shown that most of the B16F10 melanoma cells delivered to the mouse liver via the portal vein are rapidly killed in periportal zone 1 of the sinusoids. Few intact viable cells reach pericentral zone 3 of the sinusoids and of these, only a very small proportion leave the liver to colonize the lungs. The hypothesis has been advanced that one non-exclusive, potential mechanism for cancer-cell destruction in the liver is a result of the deformation of cancer cells when they enter vessels of smaller diameter than themselves.

Cancer-cell traffic in the liver. II. Arrest, transit and death of B16F10 and M5076 cells in the sinusoids.

Fluorescent probes were used to detect BUdR-labelled B16F10 and M5076 cancer cells delivered to the livers of mice via intrasplenic injection. In liver sections stained for succinic dehydrogenase, which permits the periportal, acinar zone 1 to be distinguished from the pericentral zone 3, counts were made of the zonal distribution of fluorescent, intact cancer cells and, by default, the numbers of "lost" cells. Very few intact cancer cells leave the liver from the single bolus of the intrasplenic injection, and even fewer of these generate pulmonary lesions; therefore, within the time limits of these experiments, the liver is virtually a closed system.

The differential resistance of B16 wild-type and F10 cells to mechanical trauma in vitro.

Following intravenous injection of B16 melanoma cells into mice, more than 99.9% of the cells are killed by a combination of rapid and slow processes: however, the F10 line of B16 mouse melanoma cells produces approximately 10 times as many pulmonary colonies as wild-type cells. We have attempted to determine the role of one rapid cancer cell-killing process, namely deformation-driven, loss of surface membrane integrity of the type occurring in capillaries, by the use of an in vitro model in which cells are filtered through 8-microns pores in polycarbonate membranes.

Cancer-cell traffic in the liver. I. Growth kinetics of cancer cells after portal-vein delivery.

Following the intrasplenic injection of B16F10 melanoma cells into mice, at first single cells, and later multicellular tumor foci were observed at different times in the liver. Cell numbers and tumor volumes were determined over the next 12 days, by confocal microscopy of thick liver sections. Fifteen minutes after injection, approximately 20% of the melanoma cells were identified in the liver microvasculature; after 48 hr, only 0.