Developmental response of adult mammary epithelial cells to various fetal and neonatal mesenchymes

Adult mouse mammary epithelial cells were isolated and grown in combination with mesenchyme from the following sources: embryonic preputial gland, foot skin, tail skin, genital tubercle skin, mammary gland, and neonatal uterus, vagina and urinary bladder. Following 1 month of in vivo cultivation of the tissue recombinants as grafts underneath the renal capsule of normal female or hyperprolactinaemic (pituitary-grafted) hosts, the specimens were analysed histologically and immunocytochemically for the expression of milk proteins, smooth muscle actin, and cytokeratins. Mesenchymal effects on adult mammary epithelium varied with the source of the mesenchyme and the hormonal status of the host. In normal female hosts preputial gland mesenchyme induced extensive mammary epithelial growth and ductal branching morphogenesis with epithelial differentiation and ductal pattern being comparable to that observed in homotypic recombinants composed of mammary gland mesenchyme plus adult mammary epithelium. Other mesenchymes (from foot, tail, genital tubercle and uterus) preserved ductal morphology and normal epithelial differentiation, but elicited minimal epithelial growth and branching morphogenesis in adult mammary epithelium. In association with urogenital sinus, vaginal or bladder mesenchymes ductal branching morphogenesis of the mammary epithelium was absent or greatly distorted and the epithelium exhibited a stratified cuboidal phenotype even though considerable epithelial growth had occurred. In hyperprolactinaemic hosts (which received a pituitary graft) epithelial growth, alveolar morphogenesis, and synthesis of casein and milk fat globule protein was stimulated in all tissue recombinants although to different extents. Alveolar morphogenesis and milk protein expression were extensive in tissue recombinants prepared with mesenchyme from embryonic mammary gland, preputial gland, tail skin and urinary bladder, but were minimal in tissue recombinants prepared with foot or genital tubercle skin. Few milk-protein-positive alveoli formed in tissue recombinants composed of mammary epithelium combined with urogenital sinus or vaginal mesenchyme, even following growth in pituitary-grafted hosts. These findings demonstrate: (1) that adult mammary epithelial cells are responsive to the growth-promoting influences of heterotypic embryonic and neonatal mesenchymes; (2) that mammary growth and branching morphogenesis are induced to variable extents by different mesenchymes; (3) that fibrous (non-adipose) mesenchymes are effective inducers of mammary epithelial development; and (4) that the ability to form alveoli and produce milk proteins in adult mammary epithelial cells is critically dependent upon the nature of the connective tissue environment.

Casein accumulation in mouse mammary epithelial cells after growth stimulated by different hormonal and nonhormonal agents

Mammary epithelial cells obtained from virgin mice were cultured in collagen gel with linoleic acid-containing serum-free growth medium supplemented with hormonal (PRL and progesterone, epidermal growth factor, somatomedin-C) or nonhormonal (lithium ion, phosphatidic acid containing phospholipid liposomes) growth stimulating agents. The phenotypes of the resulting progeny cells were compared by examining the ultrastructure, immunohistochemical staining for luminal epithelial and myoepithelial cells and casein, and assessing the quantity of biochemically detectable alpha- and beta-casein. Although there are some differences in ultrastructure and immunostaining in the progeny cell populations induced by different growth-promoting agents, all the cultures were able to accumulate alpha- and beta-casein on subsequent stimulation by PRL and linoleic acid in the second phase of culture. Since, in vivo, luminal epithelial cells of the mammary gland are the only cell type capable of synthesizing milk products, these results indicate that all the different growth stimulants, hormonal and nonhormonal, result in the predominant proliferation of luminal-type epithelial cells. These results have important implications for studies of the mechanism of growth control in and transformation of mammary epithelial cells.

Morphogenesis of mouse mammary epithelial cells growing within collagen gels: ultrastructural and immunocytochemical characterization

Mammary epithelial cells from adult virgin mice have been cultured within collagen gels in totally serum-free medium containing either epidermal growth factor or the mammogenic hormones, progesterone and prolactin, or prolactin alone. The cellular organization, differentiation and cell-type composition of the colonies from the three culture conditions were assessed by transmission electron microscopy and light-microscope immunocytochemistry. The epithelial cells form branching duct-like structures and, when exposed to mammogenic hormones, assume a secretory morphology (including casein micelles) similar to that seen in the early to mid-pregnant mouse.

Human breast epithelial cells in serum-free collagen gel primary culture: growth, morphological, and immunocytochemical analysis

Human breast epithelial cells derived from various sources (fibroadenoma, reduction mammoplasty, and mastectomy tissues from premenopausal patients) have been cultured in collagen gel matrix using serum-free medium. Response to various additives has been analyzed for growth-promoting effect when added to a basal medium containing insulin, cholera toxin, and BSA. A consistent observation has been the effect of EGF and cortisol in growth stimulation of human breast epithelial cells, while separately, each additive elicited only a small response. Under this condition, employing EGF and cortisol combinations, these cells gave rise to organized colonies consisting of clusters of cells, usually spherical, without any duct-like extensions. Ultrastructural and immunocytochemical studies, using a panel of monoclonal and polyclonal antibodies, have shown that cell types and features that can be identified in the original breast tissue can also be delineated in the progeny populations. The topographical feature, consisting of lumina surrounded by a single inner layer of epithelial cells and an outer layer of basal/myoepithelial cells, can be re-created in the collagen gel system starting from small clumps of cells.

Different mitogenic and phenotypic responses of human breast epithelial cells grown in two versus three dimensions

Human breast epithelial cells, derived from fibroadenomas, were cultured under conditions promoting growth in two-dimensions (2D) as monolayers using the collagen-coated dishes and in three-dimensions (3D) inside the collagen gel matrix. Both epidermal growth factor (EGF) and cortisol (F) were required for maximal stimulation in 3D growth, but only cortisol was required for 2D growth. The growth stimulation of exogenously added type IV collagen was no greater than that of type I as a substrate in both the 2D and 3D growth. Immunocytochemical staining, using a polyclonal actin antibody, showed homogeneous staining in all cells in 2D monolayers, whereas more restricted distribution was observed in 3D outgrowths in the collagen gel matrix. The same cells, when cultured in 2D vs 3D, elicit different responses and the original phenotypes may be better maintained in 3D.

Correlation between the presence of intracellular OK-432 and antitumor activity of peritoneal macrophages

The mechanism of the generation of tumoricidal macrophages by intraperitoneal administration of OK-432 was investigated. An association between the presence of intracellular FITC-conjugated OK-432 and the increase of macrophage cytostatic activity was observed after i.p. administration of OK-432. When peritoneal exudate cells were fractionated on the basis of cell size by velocity sedimentation, a higher proportion of macrophages and a strong cytostatic activity were shown in the large cell fractions. Furthermore, in these fractions, increased numbers of macrophages with intracellular FITC conjugated and 3H-acetate labelled OK-432 were observed. Thus, the more cytocidal macrophages can be identified by the presence of intracellular microorganisms. A role for OK-432 in the direct activation of macrophages is suggested.

Stimulation of mammary epithelial cell growth in vitro: interaction of epidermal growth factor and mammogenic hormones

A serum-free primary cell culture system was used to examine the direct effects and interactions of mammogenic hormones and epidermal growth factor (EGF) on the growth of mouse mammary epithelial cells. Epithelial cells were isolated by collagenase dissociation followed by Percoll gradient centrifugation and cultured within collagen gels in a mixture of Ham's F-12-Dulbecco's Minimum Essential Medium (1:1) containing insulin (10 micrograms/ml), crude soybean lecithin, trace elements, trypsin inhibitor, and antioxidants. Progesterone (P; 10(-6) - 10(-8) M) or ovine PRL (1 microgram/ml), in the absence of EGF, stimulated the growth of cells from mature virgin mice 2- to 4-fold over that of controls cultured in basal medium only. P and PRL synergized in stimulating growth 3- to 17-fold. 17 beta-Estradiol (10(-7) - 10(-10) M) alone did not stimulate growth or synergize with P and/or PRL. This lack of growth stimulation by 17 beta-estradiol was also observed in medium containing a low concentration of insulin (0.1 microgram/ml). EGF (10 ng/ml) alone stimulated growth to the same extent as the combination of P and PRL. EGF at 1, but not 10, ng/ml when combined with P and PRL could additively stimulate growth. Cells from midpregnant mice were less responsive than cells from virgin mice to the growth-stimulating effects of the combination of P and PRL (2-fold stimulation at most), but not to EGF (3- to 6-fold stimulation). Corticosterone, deoxycorticosterone, and aldosterone, but not cortisol, could synergize with PRL in stimulating the growth of cells from mature virgin mice. However, only deoxycorticosterone could stimulate growth in the absence of PRL. These results suggest that PRL, P, and adrenal corticoids may directly stimulate the growth of mouse mammary epithelial cells. The physiologically relevent adrenal corticoids, corticosterone and aldosterone, only potentiate the stimulatory effect of PRL. The hormonal stimulation of growth in vitro can be obscured by an optimum concentration (10 ng/ml) of EGF. The relative growth responses to mammogenic hormones and EGF may depend on the degree of differentiation of the cells.

[Local immunotherapy for cancer]

As for the non-specific cancer immunotherapy concerned, the effect is limited and local use of immunopotentiators which could collect effector cells around tumor tissues might be the best way of cancer immunotherapy. Intratumoral or intraperitoneal administration of large-dose of OK-432 (100 KE) has been investigated since many years with favorable results. Side effects were minimum with a few days continuing slight fever elevation. From the immunohistological examinations using monoclonal antibodies, participation of killer T cells and NK cells was confirmed after intratumoral administration of large-dose OK-432. On the other hand, after intraperitoneal administration of OK-432, neutrophil leucocytes appeared at first on the 2nd to 4th day and they were followed by lymphocytes on the 4th to 5th day and finally appeared lot of macrophages on the 6th and later days. From the results of in vitro and in vivo experiments, these macrophages seemed to play the leading role in the cytostatic activities after intraperitoneal OK-432 administration. As for the fear of introducing suppressor cells after large-dose OK-432 administration, detailed studies on suppressor activities before and after operation for gastric cancer patients revealed no particular increase of suppressor cell activities after intratumoral and intraperitoneal administration of 100 KE OK-432 as compared with curative resection cases with no OK-432 administration.

[Significance of human Tr cell in gastric cancer --with special reference to suppressor cell activity]

Peripheral blood lymphocytes from gastric cancer patients and normal donors were divided into T, non T, Tr, and T non-r cell fractions. Suppressor cell activity of each fraction and surface antigen of T cell subsets were investigated. T and Tr cell fractions activated by concanavalin A (Con A) significantly depressed the lymphocyte proliferative responsiveness (LP) to phytohemagglutinin (PHA) of responder autologous lymphocytes, but non T and T non-r cell fractions didn't. LP response to PHA of responder autologous cells were depressed by Tr cell fraction from gastric cancer patients without Con A activation, but not from normal donors. The percentage of Tr cells in T cells increased from 8.9% to 18.2% in gastric cancer patients, and from 4.7% to 9.5% in normal donors when lymphocytes were activated by Con A for 24 hours. The percentages of Tr cells reacting with OKT3, 4, and 8 monoclonal antibodies were 72.5%, 29.0% and 43.4%, respectively. Therefore, Tr cell was relatively enriched by OKT8 cell. The percentage of Tr cells and suppressor cell activity increased when normal lymphocytes were incubated with sera from gastric cancer patients for 24 hours and suppression by T, Tr and T non-r cell fractions 23%, 8% and 5%, respectively. From these results it is suggested that Tr cells contain suppressor precursors which can be activated by Con A in vitro and matured suppressor cells which have been already activated in vivo, and that higher proportion of suppressor precursors is found in gastric cancer patients as compared with normal donors. Furthermore, it is indicated that cancer sera may contain factors which induce suppressor cell and induction of suppressor cell activity requires the interaction between Tr cell and T non-r cell.

The enhancement of tumor cell susceptibility to macrophage binding and cytolysis by p-aminobenzoic acid-N-xyloside sodium salt (K-247)

The enhancement of tumor cell susceptibility to macrophage binding and cytolysis by the pretreatment of tumor cells by p-aminobenzoic acid-N-xyloside sodium salt (K-247) was investigated in the C3H/He mouse-syngeneic tumor system. Binding and cytolytic activities of Corynebacterium parvum-activated macrophages were significantly enhanced when target MM-102 and MH-134 cells were pretreated with K-247 at doses of 200 or 400 micrograms/ml, while thioglycollate-elicited macrophages showed much lower binding and lytic activities against K-247 pretreated target cells. No enhancement of these activities were observed when target cells were pretreated with D-xylose, which had no anti-tumor activity. Furthermore, in a binding assay a significant reduction of macrophage binding to target cells by the K-247 pretreated cold competitors was observed. It is suggested that target cell susceptibility to macrophage cytolytic activity might be enhanced by pretreatment with K-247, involving an initially increased target binding.

[Enhancement of antitumor activity of Propionibacterium avidum in combined with neurotropin in tumor bearing mice]

The enhancement of antitumor activity of Propionibacterium avidum (P. avidum) in combination with Neurotropin (NSP) was investigated in C3H mice-MH 134 tumor system. P. avidum (0.5 mg) and NSP (20 mg/kg) were administered on day 2 and from day 1 to 7 after tumor inoculation, respectively. When mice were treated with P. avidum in combination with NSP, a significant prolongation in survival days was observed (P less than 0.01). Treatment with P. avidum alone produced prolongation in survival days, but NSP did fail. Increase of Con-A induced suppressor cell activity and depressed proliferative response of spleen cells were observed by the treatment with P. avidum. However, recovery of proliferative response to normal level and disappearance of suppressor cell activity were observed when NSP was combined. Thus, treatment by P. avidum in combination with NSP produced a significant prolongation in survival days and it may be depending on macrophage activation by P. avidum and on the restoration of T cell functions by NSP.

Concanavalin A-induced and spontaneous suppressor cell activities in peripheral blood lymphocytes and spleen cells from gastric cancer patients

In 173 gastric cancer patients, activities of Concanavalin-A-induced suppressor cells (Con-AS) and spontaneous suppressor cells (SpS) in peripheral blood lymphocytes (PBL), splenic vein lymphocytes (SVL), and spleen cells (SCs) were investigated. Suppressions by Con-AS in PBL were significantly effective in patients of Stages III and IV, while suppressions by SpS were effective in patients with recurrent tumors. Thus, in PBLs of cancer patients, suppressor precursors, which are considered to be activated in vitro by Concanavalin-A, seemed to appear with the advances of the disease, and SpS activities, which could be already activated in vivo, seemed to increase in the terminal stage. In SCs, increased activities of Con-AS, but normal activities of SpS, were observed, and these suppressor-cell populations consisted of glass nonadherent cells. Suppressor activities of SCs would be due to suppressor T-cells, not to other types of cells. Furthermore, Con-AS existed in the medium-sized lymphocytes, which were fractionated on the basis of cell size, while SpS in the large-sized lymphocytes. A higher proportion of T-cells, bearing Fc receptors for IgG, was observed in the larger-sized lymphocyte fractions. Cell numbers in the large-sized lymphocyte fraction tended to increase with the advances of tumors. From these results, it is suggested that higher presence of suppressor precursors and the increase of SpS activities may occur in cancer patients, depending on the tumor advancing.

[Analysis of suppressor cell activities in spleen cells from gastric cancer patients and the effect of splenectomy on prognosis of gastric cancer]

In gastric cancer patients, activities of Concanavalin-A induced suppressor cells ( ConAS ) and spontaneous suppressor cells (SpS) in spleen cells (SC), peripheral blood lymphocytes (PBL) and splenic vein lymphocytes (SVL) were comparatively investigated. Suppressions by ConAS in PBL were significantly increased in patients of Stages III and IV, while suppressions by SpS were increased in patients with recurrent tumors. Elevated activities of ConAS and SpS were observed in SCs and SVLs , respectively. ConAS activities were mostly indicated in the medium sized lymphocyte fractions which were fractionated on the basis of cell size, while SpS activities in the larger sized fraction. Cell numbers in the large sized lymphocyte fraction which contained higher proportion of Tg cells and OKT8 reactive T cells, tended to increase with advances of the disease. These results suggest that spleen contained much higher proportion of suppressor precursors which might be activated to become suppressor cells with advances of the disease. Furthermore, the effect of splenectomy on the prognosis of gastric cancer was investigated in randomized controlled trial. The patients who underwent total gastrectomy and had main location of the tumor on lesser curvature region were divided into two groups at random; splenectomy (+) and splenectomy (-) groups. A suggestive prolongation of survival time was observed in splenectomy (+) group. Thus, spleen seems to contribute to the immunosuppression in gastric cancer patients and splenectomy may lead to better prognosis.

Response of end bud cells from immature rat mammary gland to hormones when cultured in collagen gel

End buds from 4- to 5-week-old rat mammary glands were isolated and cultured within a rat tail tendon collagen gel matrix. Media containing equine serum or porcine serum and cholera toxin promoted growth, but not the production of casein or thioesterase II, nor did they induce a state of differentiation as assessed by cell ultrastructure. Medium supplemented with only 5% porcine serum, insulin and cholera toxin did not support growth or differentiation. However, when prolactin, estradiol, progesterone and hydrocortisone were added to this medium, growth was stimulated greatly and a differentiated state was induced as assessed by the production of casein and thioesterase and by the appearance of a highly secretory ultrastructure.

Prognostic significance of lymphocyte proliferative responses to mitogens in gastric cancer patients

In 501 Japanese patients with gastric cancer, the relationships between preoperative lymphocyte proliferative (LP) responses to mitogens and prognosis of patients were evaluated. Peripheral blood lymphocytes were cultured in the presence of either autologous or allogeneic serum and their LP responses to phytohemagglutinin (PHA) and pokeweed mitogen were investigated. An apparent inverse relationship between LP responses and stage of the disease was found in LP responses to PHA in the presence of autologous serum. The survival rate of patients with higher responses was significantly greater than those with lower responses, when LP responses to PHA in the presence of autologous serum served as the criterion. Probabilities of staging which were computed on the basis of LP response to PHA affirmed the reciprocal relationship between LP responses and stage of the disease. From these results, it is concluded that evaluation of LP responses may be a valuable tool in the assessment of the clinical stage and in the prediction of prognosis.

[The relationship between serum immunosuppressive acidic protein (IAP) and cellular immunity in the patients with gastric cancer]

IAP (immunosuppressive acidic protein), one of the serum immunosuppressive factors, was investigated in the preoperative patients with gastric cancer. IAP values in sera from patients increased in accordance with advances of the disease. In the study of quantitative correlation of IAP with immunological parameters, IAP values correlated slightly with lymphocyte proliferative response to PHA, while a significant correlation between IAP values and spontaneous suppressor T cell activities was noted (p less than 0.01). These results suggested that IAP as well as immune complex might serve as a signal for the activation of suppressor T cells in vivo.

Growth in primary culture of mouse submandibular epithelial cells embedded in collagen gels

Mouse submandibular glands were dissociated and the epithelial cells embedded in a collagen gel matrix. A characteristic and reproducible pattern of growth was seen resulting in three-dimensional outgrowths with ductlike structures projecting into the matrix. A sustained cell growth leading to a 5 to 10-fold increase in cell number was observed in less than 2 wk. The extent of this growth was found to be dependent on serum concentration. Of the three sera tested, swine serum was found to promote greater growth compared to fetal bovine serum or horse serum. Swine serum dose response studies have shown that a concentration of 2 to 5% in the medium elicited only a modest increase, if any, in cell number compared to the initial value within a period of 2 wk. Various hormones and growth factors were then added to this "maintenance" medium. Insulin was found to stimulate growth consistently and reproducibly in a dose-dependent manner. Ultrastructurally, the resulting outgrowths were comprised of polarized cells joined by apical tight junction and desmosomes. The outgrowths produced epidermal growth factor in response to dihydrotestosterone, triiodothyronine, and cortisol. The present system provides a method for sustaining growth and functional differentiation in primary culture of mouse submandibular gland epithelial cells.

Sustained growth and three-dimensional organization of primary mammary tumor epithelial cells embedded in collagen gels

We have developed a method for embedding cells within a collagen matrix which allows sustained growth of mouse mammary tumor epithelial cells in primary culture. A characteristic and reproducible pattern of organization and growth occurs: the cells rearrange themselves and produce duct-like structures extending into the matrix, resulting in a three-dimensional outgrowth. Autoradiography showed continuous [3H]thymidine incorporation during 8 weeks in culture. An increase in DNA content of the cultured cells as a function of time was observed. Mouse mammary tumor cells cultured in the conventional monolayer system failed to show any significant increase in cell number during a culture period of 6 weeks. In addition, in such monolayer systems, cells progressively became detached from the dishes in long-term culture. The mammary epithelial cell origin of the collagen gel cell outgrowths was shown by electron microscopic demonstration of polarized cells containing tight junctions and budding mammary tumor virus particles. In addition, in vivo transplantation of collagen gel outgrowths resulted in the development of mammary adenocarcinoma histologically similar to the donor tumor. Cellular outgrowth patterns resembling those from tumor cells were also seen in similar collagen gel cultures of normal mammary cells from mouse and human and of hyperplastic alveolar nodule cells from mouse. The significance and usefulness of this system in comparison to the conventional monolayer system are discussed.