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R H Goldfarb

Publications and source records attributed to R H Goldfarb.

At least 37 records · Page 2Linked to original sources
PubMed1994

Antitumor effector cells: extravasation and control of metastasis.

To develop effective antimetastatic response, effector cells have to reach the tissue site of tumor metastasis. Different lymphocyte subsets vary in their ability to extravasate and reach sites of tissue injury or tumor growth. The ability of lymphoid cells to extravasate is a function of several different parameters, including cellular activation state and ability to release cytokines, proteolytic enzymes or to respond to chemotactic stimuli present in the tumor microenvironment. Adoptively transferred effector cells can only be therapeutically effective if they extravasate, reach the tumor or its microenvironment and interfere with tumor growth or metastasis. A large number of events that might be involved in accumulation of effector cells such as, e.g., A-NK cells in tumor metastases, are illustrated in the schema in Figure 3. The future challenge will be to gain an in-depth understanding of these events, including effector cell migration and extravasation, to assure optimal transfers of these cells to patients with metastatic disease.

Animals↗
PubMed1992

Nongranular proteolytic enzymes of rat IL-2-activated natural killer cells. I. Subcellular localization and functional role.

Our investigations indicate that a variety of neutral serine proteases exist in highly purified, IL-2-activated rat NK (A-NK) cells. These enzymatic activities are not restricted to only cytolysin-containing granules and are not defined by only the assay of N-alpha-benzyloxycarbonyl-L-lysine thiobenzylesterase activity. These activities, which we term A-NKP 1, A-NKP 2, A-NKP 3, and A-NKP 4, cleave, respectively, the following fluorogenic peptide substrates: Boc-Phe-Ser-Arg-7-amino-4-methylcoumarin (AMC, trypsin-like); Suc-Ala-Ala-Phe AMC (chymotrypsin-like); Suc-Gly-Pro-Leu-Gly-Pro AMC (collagenase-like), and Z-Phe-Arg AMC (another trypsin-like enzyme). The proteases A-NKP 1, A-NKP 2, and A-NKP 3 are not cell surface-associated and appear to be cytosolic as defined by isopycnic sucrose density gradient centrifugation. In contrast, A-NKP 4 appears to be located in lysosomes. Treatment of rat A-NK cells with protease inhibitors that inhibit A-NKP 2 and A-NKP 3 also substantially inhibit A-NK cell-mediated cytotoxicity against both NK-sensitive and -resistant targets (YAC-1 and P815, respectively). These results indicate that A-NKP2 and A-NKP 3 may play a role in IL-2-activated NK cell-mediated cytotoxicity. A variety of proteolytic enzymes, in addition to granzymes, therefore exist in A-NK cells. Our studies indicate that a prerequisite to a thorough understanding of the role of proteases in killer cell function is the investigation of several classes of enzymes in addition to granzymes contained in lytic granules.

Animals↗
PubMed1992

Tissue distribution of adoptively transferred adherent lymphokine-activated killer cells assessed by different cell labels.

Assessment of the tissue distribution of adoptively transferred adherent lymphokine-activated killer A-LAK) cells by use of 51Cr indicated that these effector cells, after an initial phase in the lungs, distributed in high numbers to liver and spleen (30% and 10% of injected dose, respectively). However, when this experiment was repeated with 125IdUrd as cell label, fewer than 2% and 0.5% of the injected cells distributed into liver and spleen respectively. To analyse this discrepancy, we compared the tissue distribution of 51Cr- and 125IdUrd-labelled A-LAK cells with that indicated by alternative direct visual methods for identification of the injected cells, such as fluorescent dyes (rhodamine and H33342) or immunohistochemical staining of asialo-GM1-positive cells. The number of i.v. injected A-LAK cells found in the liver by all visual methods ranged from 1% to 5% of the injected dose, supporting the data obtained with 125IdUrd, whereas 25%-30% of the 51Cr label was consistently found in this organ. Autoradiography of the liver 24 h after i.v. injection of 51Cr-labelled cells revealed a background activity that was four- to fivefold higher than the control level, indicating substantial non-specific accumulation in the liver of 51Cr released from A-LAK cells. We conclude that 51Cr cannot be reliably used in investigations of cell traffic to the liver because of non-specific accumulation of the 51Cr label, particularly in this organ. In contrast, labelling with 125IdUrd or rhodamine and immunohistochemical staining of asialo-GM1-positive cells appear to be reliable and essentially equivalent methods for investigations of the fate of adoptively transferred A-LAK cells. Using these methods, we found that only few A-LAK cells redistribute to the liver upon i.v., i.e. systemic, injection, whereas 40%-50% of locally (intraportally) injected A-LAK cells remain in the liver for at least 24 h.

Animals↗
PubMed1992

Therapeutic agents for treatment of established metastases and inhibitors of metastatic spread: preclinical and clinical progress.

This article reviews recently described agents for the treatment of established metastases or inhibitors of metastatic spread. Recent progress in both preclinical models of experimental metastasis and clinical evaluation is highlighted. Where possible, distinctions are made between therapeutic agents for established metastatic tumors and those that merely interfere with the process of metastasis. The approaches emphasized include radiotherapy, cytotoxic chemotherapy, targeting the metastatic process and tumor metastases (adhesion, invasion, and angiogenesis), and modulation of the immune response, including chemoimmunotherapy. Emphasis has been placed on the necessity of using appropriate animal models of metastatic disease for the discovery and development of novel and effective antimetastatic therapeutic agents. Also addressed is the likelihood that future approaches to the metastasis problem will employ novel combined antimetastatic therapeutic modalities.

Adjuvants, Immunologic↗
PubMed1991

Accumulation of adoptively transferred adherent, lymphokine-activated killer cells in murine metastases.

While close contact between lymphokine-activated killer (LAK)/adherent, lymphokine-activated killer (A-LAK) cells and tumor cells is believed to be a prerequisite for initiating the events leading to tumor cell lysis, clear evidence for the ability of these effector cells to infiltrate tumors or tumor metastases in vivo still has to be obtained. In the present study, we report that a significant fraction of adoptively transferred A-LAK cells, labeled with fluorochromes for identification, accumulates in lung and liver metastases of the B16 melanoma, the MCA 102 sarcoma and the Lewis lung carcinoma lines. Thus, 5- to 10-fold higher numbers of A-LAK cells were found in the malignant lesions compared to the surrounding normal tissue. The infiltration seemed very heterogeneous after intravenous injection of moderate numbers of A-LAK cells (15 x 10(6)). However, after adoptive transfer of 45 million A-LAK cells, an A-LAK cell/tumor cell ratio higher than 1:1 in most metastases was observed. Surprisingly, approximately 5% of the lung metastases seemed totally resistant to infiltration even though neighboring metastases were highly infiltrated. While substantial infiltration of lung metastases was seen after i.v. injection, significant infiltration of liver metastases was seen only after intraportal injection of the A-LAK cells indicating impaired traffic of intravenous injected A-LAK cells through the lung capillaries. These results present direct evidence that A-LAK cells, upon a proper route of administration, have the potential to migrate to and heavily infiltrate metastases from murine tumors of different origin.

Animals↗
PubMed1991

Establishment of cell-to-cell contact by adoptively transferred adherent lymphokine-activated killer cells with metastatic murine melanoma cells.

A murine model of pulmonary B16 melanoma was used to study the infiltration into metastases of lymphokine-activated killer (LAK) cells and adherent lymphokine-activated killer (A-LAK) cells and, specifically, to study whether A-LAK cells are able to leave the tumor microcirculation and establish cell-to-cell contact with malignant cells. Fluorescence microscopy demonstrated that A-LAK cells accumulated in metastases twice as efficiently as LAK cells during interleukin-2 stimulation. Electron microscopy of pulmonary metastases 16 hours after administration of 2.5 x 10(7) A-LAK cells revealed A-LAK cells, identified by the presence of typical two-compartment granules, in direct contact with melanoma cells. This finding was confirmed by using A-LAK cells prelabeled with polycationized ferritin. In conclusion, our observations demonstrate unambiguously the ability of adoptively transferred A-LAK cells to establish contact with extravascular metastatic melanoma cells.

Animals↗
PubMed1989

Low deformability of lymphokine-activated killer cells as a possible determinant of in vivo distribution.

Successful therapy of tumors with lymphokine-activated killer (LAK) cells is presumably dependent on their cytolytic potential and their gaining access to the target cells through the microcirculation. The latter process involves dissemination through the microvessels, adhesion to the venular walls, and extravasation through them, all of which depend on the size and deformability of these effector cells. The aim of the present study was to measure the deformability of these cells quantitatively using a micropipet aspiration technique and to analyze the deformation data using a mathematical model which yielded parameters indicative of the rigidity of the cell membrane and the cytoplasm. Adherent rat LAK cells, consisting of a highly purified population of interleukin 2-activated large granular lymphocytes, with high cytotoxicity were obtained by a recently developed method. The deformability characteristics of fresh large granular lymphocytes (mean diameter, 7.2 microns), LAK cells (11.0 microns), fresh T-cells (6.6 microns), and concanavalin A-activated T-cells (9.7 microns) were compared. LAK cells were significantly less deformable than other cell types [about one-half at an aspiration pressure of -25 mm of H2O (P less than 0.001)]. Cell deformability was independent of cell size and calcium content of the medium. Analysis of the data with the mathematical model suggested that both the cell membrane and the cytoplasmic factors contributed to the rigidity of LAK cells. This increased rigidity coupled with their large cell size may explain high retention of LAK cells in the lungs immediately after i.v. injection and a reduction in tumor targeting due to external radiation. Finally, these results suggest that LAK cell therapy might be enhanced by intraarterial injection into an organ infiltrated by tumor metastases.

Animals↗
PubMed1988

Influence of T cells on the expression of lymphokine-activated killer cell activity and in vivo tissue distribution.

Lymphokine-activated killer (LAK) cells are currently being evaluated in several cancer centers for the immunotherapy of patients with a variety of cancers. Understanding the in vivo distribution of LAK cells should help to optimize their antitumor efficacy. As a model system to examine this issue, nylon wool column-passed rat lymphocytes were cultured in the presence of rIL-2 for 1 and 2 days. The resulting cells were divided into two populations; one that adhered to the plastic flasks and the second which did not adhere. The adherent cells were found to be highly cytotoxic against NK-sensitive and NK-resistant targets, whereas the nonadherent cells were unable to kill NK-resistant targets unless T cells were removed from this population. These results indicate that T cells present in IL-2 activated bulk splenocytes may interfere with the activity of LAK cells. Adherent or nonadherent LAK cells were evaluated for their pattern of in vivo distribution after i.v. inoculation. These cells were found to display a restricted pattern of distribution, localizing mainly in the lungs at 2 h after i.v. injection but redistributing into the liver and the spleen by 24 h. LAK cells were rarely recovered from the lymphoid tissues, including the peripheral lymph nodes and the mesenteric lymph nodes. However, if T cells were not removed from the LAK cell population, some radioactivity was recovered from the peripheral and mesenteric lymph nodes. Fractionation of 2 day-activated, nonadherent population on discontinuous Percoll resulted in the enrichment of large granular lymphocyte (LGL)/LAK activity in low density fractions (42% and 45% Percoll), whereas high density fraction (70% Percoll) contained T cells which showed no cytolytic activity. Upon transfer into syngeneic rats, the 42% fraction showed typical LAK migration. In contrast, the 70% fraction showed typical T cell migration. What is more important, removal of the granulated cells resulted in a population which have no granules and resemble large agranular lymphocytes known to be pre-LGL/LAK cells. Large agranular lymphocytes showed a pattern of distribution different from both T and LGL/LAK cells.

Animals↗
PubMed1988

Interaction of tumor cells and immune system in the metastatic process.

The metastatic process is rather complicated and relatively inefficient. Millions of tumor cells are constantly shedding from the primary tumor into the blood stream, but very few of them are able to form metastatic tumors in the different organs or tissues of the host. It is widely accepted that metastatic cells have to possess a complex array of various properties that allow them to complete the metastatic cascade. The realization of the metastatic potential largely depends on the ability of tumor cells to evade host defense mechanisms. The potential role of specific and nonspecific immune mechanisms in the control of metastatic spread and growth is the subject of the present review. A better understanding of the mechanisms of antimetastatic defense is of prime importance for development of efficient immunotherapeutic methods for the treatment and eradication of disseminated tumor metastases.

Animals↗
PubMed1987

Secretion of type IV collagenolytic protease and metastatic phenotype: induction by transfection with c-Ha-ras but not c-Ha-ras plus Ad2-E1a.

Activated ras oncogene transfection into suitable recipient cells has been shown to induce the metastatic phenotype (Thorgeirsson, et al., Mol. Cell. Biol., 5: 259-262, 1985). We have used this model system to study the correlation of basement membrane collagenolysis with metastatic propensity. The c-Ha-ras oncogene alone, or combined with v-myc, transfected into early passage rat embryo fibroblasts, induce these cells to secrete high levels of type IV collagenolytic metalloproteinase and to concomitantly exhibit a high incidence of spontaneous metastases in nude mice. Cotransfection of c-Ha-ras plus the adenovirus type 2 E1a gene yields cells which are highly tumorigenic but nonmetastatic and fail to produce type IV collagenase. This effect is due to a suppression of collagenase elaboration, not increased production of a collagenase inhibitor, and not decreased production of a collagenase activator. The characteristics of the collagenase are identical to tumor type IV collagenase described previously. The nonmetastatic cells which failed to produce type IV collagenase retain the ability to secrete high levels of plasminogen activator. Transfection with the protooncogenic forms of Ha-ras or mos, or spontaneous transformation of NIH 3T3 cells or chemical transformation of BALB 3T3 cells yields cells which fail to produce collagenase, are tumorigenic, but totally nonmetastatic. These data support a biochemical linkage of type IV collagenase expression with the metastatic phenotype in this rodent system.

Adenovirus Early Proteins↗
PubMed1987

Induction of DNA synthesis in isolated nuclei by cytoplasmic factors: inhibition by protease inhibitors.

Cytoplasmic extracts from spontaneously proliferating and mitogen-activated lymphoid cells contain a protein factor called ADR (activator of DNA replication) that induces DNA synthesis in isolated quiescent nuclei. ADR-containing preparations have proteolytic activity, as indicated by their ability to degrade fibrin in a plasminogen-independent and plasminogen-dependent manner. In addition, aprotinin, a nonspecific protease inhibitor, abrogates ADR-induced DNA synthesis in a dose-dependent fashion. Preincubation studies demonstrated that the effect of aprotinin is not due to its suppressive effects on the nuclei themselves. Other protease inhibitors such as leupeptin, p-aminobenzamidine, and N-alpha-tosyllysine chloromethyl ketone are also inhibitory, but soybean trypsin inhibitor is without effect. ADR activity can be removed from active extracts by adsorption with aprotinin-conjugated agarose beads and can be recovered by elution with an acetate buffer (pH 5). These findings are consistent with the interpretation that the initiation of DNA synthesis in resting nuclei may be protease dependent and, further, that the cytoplasmic stimulatory factor we have called ADR may be a protease itself.

Animals↗