Promotion of collagen production by human fibroblasts with gastric cancer cells in vitro

Prognostic Value of Highly Expressed Type VII Collagen (COL7A1) in Patients With Gastric Cancer

Collagen is a major component in the tumor microenvironment. This study reveals a novel biomarker candidate, type VII collagen (COL7A1), in patients with gastric cancer. To identify genes differentially expressed in gastric cancer tissue, we analyzed cancerous (n = 20) and noncancerous tissues (n = 13) using a DNA microarray. To perform immunohistochemistry and validate the upregulation of COL7A1 expression, we collected 200 more gastric cancer tissues and 100 normal gastric tissues from 200 randomly selected patients who underwent gastrectomy for gastric cancer between January 2010 and December 2013. The correlations between COL7A1 expression and clinicopathological parameters and patients’ overall survival (OS) were analyzed. In the microarray, COL7A1 was upregulated in gastric cancer tissue compared with normal tissue. In the immunohistochemistry study, COL7A1 was more highly expressed in cancer tissue than in normal tissue (p = 0.001). Patients with intracellular COL7A1 expression had significantly poorer five-year OS than those with only extracellular expression (41.5 versus 69.7%, p = 0.001), and the site of expression was an independent prognostic factor of OS (hazard ratio 2.00, 95% CI 1.26–3.16, p = 0.003). Also, we found a significant association between the COL7A1 immunohistochemistry score and distant metastasis (high versus low, odds ratio 4.45, 95% CI 1.40–14.16, p = 0.011). The site and total immunohistochemistry score of COL7A1 expression in gastric cancer showed prognostic significance for OS and distant metastasis, respectively. COL7A1 could be a novel biomarker with diagnostic and therapeutic value.

Do you know the sex of your cells?

Do you know the sex of your cells? Not a question that is frequently heard around the lab bench, yet thanks to recent research is probably one that should be asked. It is self-evident that cervical epithelial cells would be derived from female tissue and prostate cells from a male subject (exemplified by HeLa and LnCaP, respectively), yet beyond these obvious examples, it would be true to say that the sex of cell lines derived from non-reproductive tissue, such as lung, intestine, kidney, for example, is given minimal if any thought. After all, what possible impact could the presence of a Y chromosome have on the biochemistry and cell biology of tissues such as the exocrine pancreatic acini? Intriguingly, recent evidence has suggested that far from being irrelevant, genes expressed on the sex chromosomes can have a marked impact on the biology of such diverse tissues as neurons and renal cells. It is also policy of AJP-Cell Physiology that the source of all cells utilized (species, sex, etc.) should be clearly indicated when submitting an article for publication, an instruction that is rarely followed (http://www.the-aps.org/mm/Publications/Info-For-Authors/Composition). In this review we discuss recent data arguing that the sex of cells being used in experiments can impact the cell's biology, and we provide a table outlining the sex of cell lines that have appeared in AJP-Cell Physiology over the past decade.

MRI T2 hypointensity of metastatic brain tumors from gastric and colonic cancers

BACKGROUND

Metastatic brain tumors from gastric and colon cancers are frequently revealed by hypointensity on T2-weighted magnetic resonance images (MRIs). However, the reason for this T2 hypointensity has yet to be clarified. We hypothesize that it is due to collagen deposition within the tissues.

METHODS

Seven metastatic brain tumors, from 3 gastric cancers and 4 colon cancers were investigated. The degree of hypointensity of these tumors in T2-weighted images was quantitatively assessed as the ratio of gray-scale densities of tumor to brain using ImageJ. The result was compared with the amount of collagen in the resected specimens, which was quantified by ImageJ analysis software, utilizing the colour deconvolution method following Azan-Mallory staining. The degree of hypointensity was also compared with the ratio of viable epithelial component area/whole tissue area. Additionally, collagen distribution was studied by immunohistochemical staining.

RESULTS

There was a clear negative correlation between intensity in T2-weighted images of these metastatic tumors and the amount of collagen they contained (R (2) = 0.766). However, there was no significant correlation between the T2 intensity and the ratio of viable epithelial component. Immunohistochemical analysis revealed that collagen types I, III, VII, X, and XI were expressed in the epithelial components and types IV, V, and VI were expressed in the stromal areas of the metastatic tumors. Collagen deposition was observed not only in stromal fibrous areas, but also in cytoplasmic areas in these metastatic tumors.

CONCLUSIONS

Hypointensity of metastatic brain tumors arising from gastric and colonic cancers may be due to the accumulation of collagen in the tissues.

Analysis of cell type-specific responses mediated by the type IV secretion system of Helicobacter pylori

Helicobacter pylori persistently infects the human stomach and can cause gastritis, gastric ulceration, and gastric cancer. The type IV secretion system (TFSS) of virulent H. pylori strains translocates the CagA protein, inducing the dephosphorylation of host cell proteins and leading to changes in the morphology or shape of AGS gastric epithelial cells. Furthermore, the TFSS is involved in the induction of proinflammatory cytokines. While the H. pylori genes required for TFSS function have been investigated systematically, little is known about possible host cell factors involved. We infected 19 different mammalian cell lines individually with H. pylori and analyzed CagA translocation, dephosphorylation of host cell proteins, chemokine secretion (interleukin-8 and macrophage inflammatory protein 2), and changes in cellular phenotypes. Our results demonstrate that not only bacterial but also host cell factors determine the cellular response to infection. The identification of such unknown host cell factors will add to our understanding of host-pathogen interactions and might help in the development of new therapeutic strategies.

Transcription of cytokeratins 8, 18, and 19 in bone marrow and limited expression of cytokeratins 7 and 20 by carcinoma cells: inherent limitations for RT-PCR in the detection of isolated tumor cells

The suitability of "real-time" quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of isolated carcinoma cells in bone marrow was investigated by evaluating the expression of cytokeratin (CK)7, CK8, CK18, CK19, and CK20 in 17 gastrointestinal cancer cell lines, 64 control bone marrow specimens from noncancer patients, and 30 bone marrow specimens from patients with gastric or colorectal cancer. RT-PCR products for CK8 and CK18 were detected in all cancer cell lines, but only 16, 5, and 11 cell lines provided evidence for CK19, CK7, and CK20 transcription. Variable numbers of bone marrow specimens from noncancer patients demonstrated background transcription of CK8 (78.1%), CK18 (95.3%), CK19 (35.9%), CK20 (29.6%), and CK7 (16.7%). Maximal background transcription for CK8, CK18, and CK19 ranged from 52.2 to 56.1 copies/10(3) copies glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the corresponding values of 0.06 and 0.76 copies for CK7 and CK20 being distinctly lower. When maximal background values were used as a threshold value to define positivity in tumor cell dilution experiments, sensitivity levels of one tumor cell in 10(4) bone marrow cells were determined for CK7 and CK20 RT-PCR assays. Maximal background expression values of the different CKs as obtained in the control series were exceeded once (CK20), twice (CK18 and CK19), and 18 times (CK7) in bone marrow specimens from cancer patients, with none of these specimens exceeding the maximal background expression value of CK8. We conclude that RT-PCR for CK8, CK18, and CK19 cannot be recommended for the detection of isolated tumor cells in bone marrow of cancer patients. On the other side, the limited number of gastric and colorectal cancer cell lines expressing CK7 and CK20 indicates that assay sensitivity for these CKs might be limited because of their selective expression by carcinoma cells.

Collagen biosynthesis in gastric cancer: immunohistochemical analysis of prolyl 4-hydroxylase

BACKGROUND AND OBJECTIVES

The mechanism of the desmoplastic response in gastric carcinoma tissues is largely unknown. The objective of this study is to determine the localization of prolyl 4-hydroxylase (PH), an enzyme that plays a crucial role in collagen biosynthesis.

METHODS

Freshly prepared gastric carcinoma tissues from 51 cases, including 13 of the scirrhous type (diffusely infiltrative type), were immunostained by using monoclonal antibodies to human placental PH.

RESULTS

Although cytoplasmic staining for PH was observed in both fibroblasts and carcinoma cells, there was increased expression of the alpha-subunit in fibroblasts and no difference in expression between the scirrhous and non-scirrhous type gastric carcinomas. In scirrhous type samples, there was increased PH expression in fibroblasts located in the tumor periphery when compared with fibroblasts in the tumor center. These findings suggested that maintenance of a balance between production and degradation of collagen in gastric carcinoma tissues might be important for stroma formation.

CONCLUSIONS

It is speculated that activated fibroblasts participate in collagen biosynthesis at the tumor periphery rather than in the tumor center and that increased collagen biosynthesis at the tumor periphery in scirrhous gastric carcinoma may assist further invasion of tumor cells.

Collagen and elastin synthesis by desmoid tumor in vitro

In order to characterize human desmoid tumors in vitro, the production of collagen and elastin and the expression of collagen types alpha1(I), alpha1(III) and transforming growth factor (TGF)-beta1 mRNA were investigated in six desmoid tumors; five derived from familial adenomatous polyposis patients and one from a sporadic case. The proportion of collagen production to total protein production was determined by 3H-imino acid incorporation, an indicator of collagen synthesis, using high-performance liquid chromatography (HPLC). The proportion of collagen production to total protein production was much higher in all six desmoid tumors compared with human skin fibroblasts (HSF). Quantitatively, the rate of elastin synthesis in desmoid tumor cells monitored by valine-proline peptide was also significantly higher than in HSF. Pro-alpha1(I) collagen mRNA was highly expressed in both desmoid tumors and HSF at approximately the same level, whereas pro-alpha1(III) collagen mRNA was more abundant in some of the desmoid tumors than the normal skin fibroblastic cell lines. Tumor growth factor-beta1 mRNA, which is believed to stimulate collagen synthesis, was expressed in both desmoid tumors and HSF to the same extent. These results demonstrate the increased formation of collagen and elastin in desmoid tumors in vitro and suggest that the increased synthesis of elastin rather than of collagen and TGF-beta1 may be involved in increased fibrogenesis by desmoid tumors.

Differential responses of scirrhous and well-differentiated gastric cancer cells to orthotopic fibroblasts

Scirrhous gastric cancer cells proliferate rapidly with fibrosis, when the cancer cells invade into the submucosa of the stomach. To investigate the mechanisms responsible for the rapid proliferation, the growth interaction between gastric cancer cells and fibroblasts was examined. Human gastric cancer cell lines established from scirrhous carcinoma or well-differentiated adenocarcinoma were used. Human fibroblast cell lines were obtained from various organs. The growth interaction between gastric cancer cells and fibroblasts was examined by calculating the number of cancer cells or by measuring [3H]thymidine incorporation of cancer cells. Gastric fibroblasts specifically stimulated the growth of scirrhous gastric cancer cells, but not that of well-differentiated adenocarcinoma cells. The growth factor(s) produced from gastric fibroblasts were then partially purified and characterised. The growth-promoting factor(s) had apparent molecular weights of 10000 dalton and was sensitive both to heat and proteinase treatment. No inhibition for the factor(s) was achieved with defined anti-growth factor antibodies. In this study, differential responses of scirrhous and well-differentiated gastric cancer cells to orthotopic fibroblasts were shown. Rapid proliferation of scirrhous gastric carcinoma should be partly controlled by orthotopic fibroblasts. The growth factor(s) from gastric fibroblasts, which was distinct from various defined growth factors such as epidermal growth factor (EGF), basic fibroblast growth factor (b-FGF), transforming growth factor-alpha (TGF-alpha), keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF), insulin-like growth factor I (IGF-I), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF) and transforming growth factor beta 1 (TGF-beta 1) may play an important role in the progression of scirrhous gastric cancer cells.

Role of orthotopic fibroblasts in the development of scirrhous gastric carcinoma

We examined the interaction between scirrhous gastric cancer cells and organ-specific fibroblasts in vivo and in vitro. Co-inoculation of scirrhous gastric cancer cells with gastric fibroblasts into nude mice specifically increased tumorigenicity, compared with that of gastric cancer cells alone. Furthermore, the histologic findings of the xenograft produced by co-inoculation with gastric fibroblasts was similar to that of human scirrhous gastric carcinoma. Conditioned medium from gastric fibroblasts significantly stimulated the growth of gastric cancer cells. These findings suggest that the growth of scirrhous gastric cancer cells was affected by orthotopic fibroblasts.

Clinical studies of type-I procollagen carboxyterminal peptide in serum of patients with gastric cancer: comparison with CEA and CA19-9

The serum level of a newly developed monoclonal antibody against type-I procollagen carboxyterminal peptide (P-1-P) was determined in patients with gastric cancer. The location of P-1-P in gastric cancer tissue was also investigated. We found that: (1) The serum P-1-P level and the positivity rate in patients with gastric cancer were similar to those in patients with other malignant or benign GI diseases and healthy individuals. (2) In patients with gastric cancer, the P-1-P positivity rate was significantly lower than that of CEA or CA19-9. (3) In patients with gastric cancer, the P-1-P positivity rate increased as the disease stage advanced. (4) Among patients with gastric cancer, the P-1-P positivity rate was significantly higher in those with scirrhous type than in those with medullary or intermediate type. (5) P-1-P was detected in the cytoplasm of cancer cells. P-1-P staining was stronger in scirrhous type and histologically undifferentiated gastric cancer. These results show that P-1-P can serve as a good marker for scirrhous type gastric cancer. The production of collagen by cancer cells themselves seems to be involved in collagen production in scirrhous type gastric cancer.

Synthesis of the third component of complement (C3) by human gastric cancer-derived cell lines

This is a study of complement components secreted by gastric cancer-derived cell lines (MKN28, MKN45, MKN74 and KATO-III), each of which has a different histological origin. Haemolytic activity of complement component was detected only in the culture supernatant of KATO-III (C2 activity) and in that of MKN45 (C5 activity). However, the third component of complement, C3, was detected by an ELISA assay in the supernatants of all cell lines. In our studies focusing on C3 production by these cell lines, we have found that: (i) tumour necrosis factor (TNF) induced an increase in the amount of secreted C3 in a dose- and time-dependent fashion; (ii) TNF (10 U/ml) stimulated C3 secretion by these cell lines to levels of 25.4-62.9 ng C3/10(6) cells per 24 hours; (iii) C3 haemolytic activity was detected in supernatants of TNF-stimulated cell lines. The mean specific activities of C3 by TNF (10 U/ml)-stimulated cell lines were 1.2-5.6 x 10(5) effective molecules/ng (e.m./ng), when that of C3 in normal human serum (NHS) was 1.7 x 10(6) e.m./ng; (iv) de novo synthesis of C3 by these cell lines was demonstrated by the effect of cycloheximide and by the incorporation of 35S-methionine into secreted C3; (v) immunoblot analysis of culture supernatants indicated that secreted C3 was mainly composed of C3 alpha and C3 beta chains, but pro-C3 was also present. These results, which show the de novo synthesis and secretion of C3 by all the tested gastric cancer-derived cell lines in response to TNF, suggest the possibility that C3 may be secreted in the gastric wall as part of its normal physiology, or as a result of tumour pathology, and thereby participate in local immune or inflammatory responses.

Retroperitoneal fibrosis associated with scirrhous gastric cancer

A case of retroperitoneal fibrosis associated with scirrhous gastric cancer is reported. A sixty two-year-old Japanese female was admitted because of acute renal failure. The patient's serum creatinine level showed 3.2 mg/dl while the blood urea nitrogen level was 23 mg/dl. An ultrasound study of the upper abdomen revealed bilateral hydronephrosis. Drip infusion pyelography revealed a dilated right renal pelvis without ureteral obstruction. The left kidney was not opacified, suggesting a functional disorder. Gastrography and gastrofiberscopy revealed scirrhous gastric cancer. Signet ring cell carcinoma was later demonstrated histologically by biopsy specimens. CT demonstrated a prominent thickening of the gastric wall and hydronephrosis, although no prevertebral soft tissue masses were observed. A total gastrectomy was performed with failure to surgically decompress the ureters because fibrous plaque had firmly enveloped the retroperitoneal structures. Biopsy specimens of the retroperitoneum revealed an invasion of the tumor cells and prominent fibrosis. As an etiology of renal failure, ureteral stenosis resulting from secondary retroperitoneal fibrosis was also considered.

Establishment and characterization of a human gastric scirrhous carcinoma cell line in serum-free chemically defined medium

We have established a human gastric scirrhous carcinoma cell line (designated as HSC-43) in a serum-free chemically defined medium (CDM) without any polypeptide growth factor, from a primary tumor of a 56-year-old male patient. HSC-43 cells grew in vitro in adherence with a population doubling time of 55 hr, and had the cytological properties of mucinous epithelial tumor cells. Cytogenetic analysis of the cells revealed pseudotetraploidy, with structural abnormalities of deletion at chromosome Iq25 and with 3 marker chromosomes. Some cells had retained features of signet-ring cells and caused fibroblastic proliferation when transplanted into athymic nude mice. The possible involvement of transforming growth factor-alpha (TGF-alpha), and its receptor, the epidermal-growth-factor receptor (EGFR), on the growth of HSC-43 cells was studied. Synthesis and secretion of TGF-alpha by HSC-43 cells were confirmed by biological assay and enzyme-linked immunosorbent assay. Radioreceptor analysis showed the presence of receptors for EGF in HSC-43 cells. Proliferation of HSC-43 cells was inhibited by antibodies against TGF-alpha and/or the EGFR. However, neither TGF-alpha nor epidermal growth factor (EGF) was effective in stimulating the cell growth of HSC-43 cells, irrespective of the cell density when supplemented exogenously. Our data suggest that TGF-alpha and EGFR play a role in the autocrine growth of HSC-43 cells. This may be another example of growth regulation of gastric carcinoma.

Effects of pyrroloquinoline quinone (PQQ) and PQQ-oxazole on DNA synthesis of cultured human fibroblasts

The effects of pyrroloquinoline quinone (PQQ) and PQQ-oxazole (PQQ-glycine adduct) on DNA synthesis were examined using cultured human fibroblasts. Confluent fibroblasts were cultured in serum-free Dulbecco's modified Eagle's media, and various concentrations of PQQ and PQQ-oxazole were added to the media. After incubation for 24 h, [3H]thymidine was added to the media as an indicator for DNA synthesis of the cells. The thymidine incorporation into the cells was significantly enhanced even in the presence of very low concentrations of PQQ (0.003-0.03 microM); it remained significantly enhanced, up to 30 microM PQQ. However, the incorporation remarkably decreased at 750-1500 microM of PQQ. In contrast to the results for PQQ, DNA synthesis was not stimulated by addition of 0.003-3 microM PQQ-oxazole, but it was slightly enhanced at concentrations 15-750 microM. In morphological examination of the cultured human fibroblasts, cell density was increased by addition of 0.003-30 microM PQQ when compared with that of the control, supporting the above biochemical data. However, there were no distinct differences in morphological effect between PQQ and PQQ-oxazole.

The desmoplastic response: induction of collagen synthesis by melanoma cells in vitro

When cells from the human malignant melanoma cell line, UCT-Mel 7, were injected into athymic nude mice, tumours developed that were intensely infiltrated with fibrous tissue. In an attempt to reproduce this desmoplastic response in vitro, we co-cultured fibroblasts with UCT-Mel-7 cells, and observed a 2-fold increase in the rate of fibroblast collagen synthesis. This was associated with an increase in the amount of collagen mRNA present in co-cultured fibroblasts. The stimulation was both dose- and time-dependent, with maximal stimulation at a melanoma cell:fibroblast ratio of 1:1. Analysis of the kinetics of proline incorporation into collagen showed that co-culture affected the maximal rate of proline incorporation; no effect was observed on the concentration of proline required for 50% maximal collagen synthesis. The induction of fibroblast collagen synthesis showed an absolute requirement for close proximity between the fibroblasts and the melanoma cells. No soluble fibrogenic factor released by melanoma was detected.

Enhancement of mucus accumulation in a human gastric scirrhous carcinoma cell line (KATO-III) by fibroblast-tumor cell interaction

Human fibroblasts (WI-38 cells) were found to enhance mucus accumulation by human scirrhous carcinoma cells (KATO-III cells). Coculture of KATO-III with WI-38 cells resulted in enlargement of the KATO-III cells and increases in the proportions of PAS- and colloidal iron-positive KATO-III cells. These morphological alterations were reversed when the KATO-III cells were again cultured without WI-38 cells. Conditioned media from cultures of WI-38 cells or cocultures of KATO-III and WI-38 cells induced the same morphological alterations in KATO-III cells, suggesting that WI-38 cells produce a factor or factors that enhance mucus accumulation in KATO-III cells. This factor seemed to be a protein with a molecular weight of more than 10,000 daltons.

Immunoelectron microscopic localization of human type III collagen in human gastrointestinal carcinomas

Ultrastructural immunolocalization of human type III collagen/procollagen was investigated in 28 cases of human gastrointestinal carcinoma by the pre-embedding method using a monoclonal antibody. In addition to immunoreactivity on collagen fibers, amorphous or finely fibrillar immunoreactive substances were observed in the extracellular matrix adjacent to the plasma membrane and in the cisternae of rough endoplasmic reticulum (rER). These substances were considered to represent type III procollagen and/or collagen before fiber formation. Cytoplasmic recesses containing immunoreactive fibers were also observed. These findings related to collagen production were detected in stromal fibroblasts in 16 of 28 cases and in carcinoma cells in six of 28 cases. The positivity rate of these findings was lower in diffuse-type gastric carcinoma. The present study thus clarified further details of collagen production and secretion, and revealed that carcinoma cells may also be involved in the production of stromal collagen in some cases as well as stromal fibroblasts.

Expression of TGF-beta and procollagen type I and type III in human gastric carcinomas

To elucidate the difference between scirrhous and non-scirrhous gastric carcinomas, we examined the expressions of TGF-beta, procollagen type I and type III in 7 gastric carcinoma cell lines and 37 gastric carcinoma tissues, and also examined the effect of TGF-beta on the expression of procollagen mRNA by TMK-I cells. TGF-beta mRNA was detected in all the tumors examined in vivo and in vitro. Interestingly, 9 (90%) of 10 scirrhous gastric carcinomas revealed higher levels of TGF-beta mRNA than normal tissues, while 8 (38%) of 21 well-differentiated adenocarcinomas had higher TGF-beta mRNA levels than normal tissues. As for procollagen mRNA, most of the human gastric carcinoma cell lines expressed type-I procollagen mRNA and MKN-I expressed type-III procollagen mRNA. Furthermore, procollagen type-I mRNA accumulation in TMK-I cells was increased by exogenous TGF-beta. Most of the tumor tissues from surgical specimens expressed higher procollagen mRNA than normal tissues. These results indicate that TGF-beta produced by carcinoma cells might stimulate collagen synthesis not only by fibroblasts but also by carcinoma cells themselves, leading to diffuse fibrosis of scirrhous gastric carcinomas.

Morphological changes in a human scirrhous gastric carcinoma cell line (KATO-III) when cultured in collagen-coated dishes

The morphological differences between cells of a human scirrhous gastric carcinoma cell line (KATO-III) cultured in plastic dishes and in collagen-coated dishes were examined by phase-contrast and electron microscopy. When KATO-III cells were inoculated into plastic dishes, a few cells became attached to the surface of the dishes and the rest remained in suspension. However, when they were inoculated into collagen-coated dishes, they all remained in suspension. In both types of dish, most of the cells in suspension were single although a few were in clusters. The cells in suspension in collagen-coated dishes differed in morphology from those in the plastic dishes. They had abundant cytoplasm, well-developed Golgi complexes, and many microvillus-like cell protrusions. Moreover, they had hemidesmosome-like and desmosome-like structures on their surface and an increased amount of intracytoplasmic desmosome-like structures. The cells in clusters in the collagen-coated dishes were closely connected by junctional complexes, such as tight junctions, desmosomes and interdigitations, whereas those in plastic dishes were linked only by desmosomes. These results suggest that collagen affects the morphology of human scirrhous carcinoma cells.

Immunohistochemical identification of type I procollagen in tumour cells of scirrhous adenocarcinoma of the stomach

Human gastric carcinomas were tested for their immunohistochemical reactivity with anti-type I procollagen antiserum. In all specimens of scirrhous carcinomas, staining of the tumour cells was strongly positive, while in medullary carcinomas staining of the tumour cells was generally poor. These results suggest that the tumour cells in scirrhous carcinomas produce collagen in their stroma.

Pathological studies on three cases of cancer treated with polysaccharides from human-type Mycobacterium tuberculosis. Antitumor activity through collagen fiber proliferation

Three cases of cancer treated with SSM (Special Substance, Maruyama: a polysaccharide extract from Mycobacterium tuberculosis) for a long period were studied pathologically following biopsies and autopsies. The most significant antitumor activity resulting from SSM treatment was found to be collagenation from stromal cells and the cancer cells themselves. Another significant finding was that collagenation was promoted by macrophages which had been stimulated non-specifically. However, it was apparent that SSM-A or B had to be used efficiently and quickly in order to prevent invasion or metastasis of cancer. Collagenation due to SSM treatment was more marked in metastatic cancer lesions in the liver than those in the lung. In a case of breast cancer reported in a previous investigation of SSM treatment, remarkable calcification was found in a metastatic cancer lesion which had become confined through collagenation, thus preventing cancer cell metastasis. The collagenation of cancerous lesions through SSM treatment resembled the healing of caseous tuberculosis lesions through a similar mechanism.

Antitumor effects of polysaccharides of human-type Mycobacterium tuberculosis on collagenation in human cancer xenografts

The most important activity of SSM is stimulation of collagenation from cancer-infiltrated stromal tissue which confines the cancer. In order to elucidate the proliferative responses of collagen in cancer, single and double xenografts were prepared by transplantation of human gastric cancer (HGC), human lung cancer (HLC), and NB41A3 (mouse neuroblastoma) into nude mice. The collagen responses were dependent on the type of cancer cell used, particularly the cell membranes. SSM distinctly stimulated the proliferation of collagen fibers which showed a response to these cancer cells. When examined by CD, stromal collagenation was found to be dependent upon changes in the molecular structure of the cancer cell membrane. One of the glycoproteins, fibronectin, was presumed to be the most important of the substances involved.