Connective tissue changes in cancer

Advances and challenges in label-free nonlinear optical imaging using two-photon excitation fluorescence and second harmonic generation for cancer research

Nonlinear optical imaging (NLOI) has emerged to be a promising tool for bio-medical imaging in recent times. Among the various applications of NLOI, its utility is the most significant in the field of pre-clinical and clinical cancer research. This review begins by briefly covering the core principles involved in NLOI, such as two-photon excitation fluorescence (TPEF) and second harmonic generation (SHG). Subsequently, there is a short description on the various cellular components that contribute to endogenous optical fluorescence. Later on the review deals with its main theme--the challenges faced during label-free NLO imaging in translational cancer research. While this review addresses the accomplishment of various label-free NLOI based studies in cancer diagnostics, it also touches upon the limitations of the mentioned studies. In addition, areas in cancer research that need to be further investigated by label-free NLOI are discussed in a latter segment. The review eventually concludes on the note that label-free NLOI has and will continue to contribute richly in translational cancer research, to eventually provide a very reliable, yet minimally invasive cancer diagnostic tool for the patient.

Breast carcinoma-associated fibroblasts and their counterparts display neoplastic-specific changes

It has become clear that the initiation and progression of carcinomas depend not only on alterations in epithelial cells, but also on changes in their microenvironment. To identify these changes, we have undertaken cellular and molecular characterization of carcinoma-associated fibroblasts (CAF) and their tumor counterpart fibroblasts (TCF) isolated from 12 breast cancer patients. Normal breast fibroblasts (NBF) from plastic surgery were used as normal control. We present evidence that both CAFs and TCFs are myofibroblasts and show tumor-associated features. Indeed, the p53/p21 response pathway to gamma-rays was defective in 70% CAFs, whereas it was normal in all the TCF and NBF cells. In addition, the basal levels of the p53 and p21 proteins were significantly low in 83% of CAFs and modulated in the majority of TCFs compared with NBFs. Interestingly, both TCFs and CAFs expressed high levels of the cancer marker survivin and consequently exhibited high resistance to cisplatin and UV light. Moreover, most CAFs were positive for the proliferation marker Ki-67 and exhibited high proliferation rate compared with NBFs and TCFs. However, proliferating cell nuclear antigen was highly expressed in both CAFs and TCFs. Using the two-dimensional gel electrophoresis technique, we have also shown that CAF, TCF, and NBF cells present different proteome profiles, with many proteins differentially expressed between these cells. Taken together these results indicate that different genetic alterations can occur in breast CAFs and their corresponding adjacent counterparts, showing the important role that stroma could play in breast carcinogenesis and treatment.

Cell-matrix interactions in cancer spreading--effect of aging

Passage of connective tissue barriers is a compulsory step in cancer spreading. This process involves a series of steps involving cell-matrix interactions. The complexity of these steps increased considerably during the last decades as a result of the identification of a large number of newly discovered macromolecular components of the extracellular matrix (ECM). It was also recognized that malignant cells can and do modify the production as well as the degradation of ECM components. The rapid development of aging biology during the second-half of the last century also contributed to the complexity but also to the importance of the newly emerging picture of cancer progression as a function of age. The structure and composition of the ECM is strongly age-dependent and may well represent one of the important factors influencing the age-distribution of human malignancies. As will be evident from the following reviews this relatively new and rapidly increasing picture of the age-dependence of cell-matrix interactions and cancer spreading should trigger more intense efforts on this relatively new discipline in cancer research.

Extracellular matrix components in breast carcinomas

A malignant process interferes with the normal 'programme' of extracellular matrix biosynthesis and can modify extensively the structure and composition of the matrix. This effect appears to be attributable to several processes such as direct production of some selected matrix macromolecules by malignant cells or indirectly by the production of factors by malignant cells interfering with the regulation of normal matrix production. Other possibilities may also exist, such as the direct action of an environmental carcinogen on otherwise normal mesenchymal cells. The result is a more or less profound modification of tissue structure and composition with possible feedback effects on the malignant process. Some examples will be discussed such as elastin production by some tumours as well as the biosynthesis of some other selected matrix macromolecules as tenascin and osteopontin by breast tumours. Although the detailed mechanisms of these specific matrix productions is not yet completely elucidated, the rapidly increasing knowledge on the regulation of specific matrix production process and deranged matrix production might represent a new area of crosstalk between cancer research and matrix biology.

Promotion of colon cancer metastases in rat liver by fish oil diet is not due to reduced stroma formation

Recently, it was demonstrated that dietary omega-3 polyunsaturated fatty acids (PUFAs) induce 10-fold more metastases in number and 1000-fold in volume in an animal model of colon cancer metastasis in rat liver. It was observed that tumors of rats on a fish oil diet lacked peritumoral stroma unlike tumors in livers of rats on a low fat diet or a diet containing omega-6 PUFAs. In the present study, only one-third of the tumors in livers of rats on omega-3 PUFA diet contained peritumoral stroma, whereas peritumoral stroma was present in 87% of the tumors in livers of rats on low fat diet. To explain these findings, we tested the hypothesis that fish oil exerts a direct inhibiting effect on the formation of extracellular matrix in tumor stroma as a consequence of blocking transformation of fat storing cells into myofibroblasts. It was found with immunohistochemical analysis of desmin as marker for fat storing cells and alpha-smooth muscle actin as marker for myofibroblasts that numbers of myofibroblasts were higher in tumors containing intratumoral stroma only than in tumors containing both peritumoral and intratumoral stroma. As most of the tumors in fish oil-treated rats contained intratumoral stroma only, this suggests that transformation of fat storing cells into myofibroblasts was highest in tumor stroma of fish oil-treated rats. Therefore, it is unlikely that the lack of stroma around tumors in fish oil-treated rats is due to inhibition of transformation of fat storing cells into myofibroblasts, but lack of peritumoral stroma is rather a consequence of rapid development of tumors in livers of fish oil-treated rats.

Fibronectin is chemotactic for CT 26 colon carcinoma cells: sub-lines selected for increased chemotaxis to fibronectin display decreased tumorigenicity and lung colonization

CT 26 murine colon carcinoma cells demonstrated directional migration (chemotaxis) in response to fibronectin (FN). Sub-lines were derived by positive and negative selection to FN across Transwell filters of 8 microm pore size. The FL6 sub-line (positively selected) demonstrated a significantly increased chemotactic response (P<0.01) to FN compared with parental CT 26 cells, while the FU7 sub-line (negatively selected) showed a reduced chemotactic response to FN (P<0.01). Comparable levels of alpha4, alpha5, alphav and beta1 integrins, which mediate FN attachment, were expressed on positively and negatively selected sub-lines and parental CT 26 cells. Activation of integrins with Mn2+ suggested that the integrins expressed on FL6 cells were in the fully activated state; in contrast FU7 cells displayed only partially activated integrins. Cell attachment and integrin activation status of the sub-lines correlated with their chemotactic response to FN. In vivo FL6 cells showed a significantly reduced tumour growth rate s.c. and a reduction in the number of lung colonies formed following i.v. injection compared with parental CT 26 and FU7 cells. In contrast FU7 cells displayed a significant increase in s.c. tumour growth and the number of lung colonies when compared with the parental line and FL6 sub-line. The results indicate that interaction between integrin receptors expressed on cancer cells and FN plays a central role in the chemotactic response of CT 26 colon carcinoma cells, and that in this model cells selected for chemotaxis to FN displayed a reduced malignant potential.

Human ductal adenocarcinomas of the pancreas express extracellular matrix proteins

Pancreatic ductal adenocarcinomas are characterised by a dense connective tissue reaction. To test the hypothesis that stroma components are synthesised and produced by the tumour cells themselves, eight cell lines as well as six xenografted tumours from human ductal adenocarcinomas of the pancreas were examined for the expression of extracellular matrix proteins (ECM), using cDNA probes and antibodies to collagen types I, III and IV, vitronectin, fibronectin, undulin and laminin. All tumour cell lines (CAPAN-1, CAPAN-2, AsPC-1, BxPC-3, PANC-1, PaCa-2, PaCa-3, PaCa-44) and xenografted human pancreatic tumours expressed at least one of the examined ECM at the RNA (collagen type IV > laminin = fibronectin = vitronectin > collagen type III > undulin > collagen type I) or protein level (collagen type IV = collagen type III > vitronectin > laminin > collagen type I = fibronectin > undulin). In nude mouse tumours expression of laminin and collagen I was most pronounced in well-differentiated carcinomas. In a few tumours, collagen type III, vitronectin and undulin were expressed on the luminal side of the neoplastic glands, suggesting loss of normal polar differentiation. Incubation with fetal calf serum modulated ECM RNA levels to a varying extent in all but one cell line (AsPC-1). The results suggest that human pancreatic ductal adenocarcinomas cells are capable of synthesising and producing extracellular matrix proteins in vitro and in vivo, but that the extent and pattern of ECM expression differs between the various tumours and conditions tested.

Experimentally induced colon cancer metastases in rat liver increase the proliferation rate and capacity for purine catabolism in liver cells

Metastases in rat liver were generated experimentally by intraportal injection of colon cancer cells to investigate the effects of cancerous growth on the metabolism of surrounding liver tissue. Maximum activities (capacity) of glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, lactate dehydrogenase, succinate dehydrogenase, alkaline phosphatase, 5'-nucleotidase, xanthine oxidoreductase, purine nucleoside phosphorylase and adenosine triphosphatase have been determined. Two types of metastases were found, a small type surrounded by stroma and a larger type in direct contact with hepatocytes. Both types affected the adjacent tissue in a similar way suggesting that the interactions were not mediated by stroma. High capacity of the degradation pathway of extracellular purines released from dead cells of either tumours or host tissue was found in stroma and sinusoidal cells. Metastases induced both an increase in the number of Kupffer cells and proliferation of hepatocytes. The distribution pattern in the liver lobulus of most enzymes investigated did not change distinctly. However, activity of alkaline phosphatase, succinate dehydrogenase and phosphogluconate dehydrogenase was increased in hepatocytes directly surrounding metastases. These data imply that the overall metabolic zonation in liver lobuli is not dramatically disturbed by the presence of cancer cells despite the fact that various metabolic processes in liver cells are affected.

Purification and characterization of collagens from rat fibrosarcoma induced by 3-methylcholanthrene

The distribution of various collagen types was studied in rat fibrosarcoma. Collagens extracted from fibrosarcoma tissue were characterized by the criteria of solubility in NaCl, SDS-PAGE, ion exchange chromatography, CNBr peptide mapping and amino acid analysis. Fibrosarcoma was found to produce excess amount of type V, type I trimer and type III collagens; comparatively, type I collagen and total collagen content were noticed to decrease in fibrosarcoma. We observe that the increase in type V collagen content in fibrosarcoma might be due to the enhanced transcription of type V collagen gene. Increased type I trimer collagen in fibrosarcoma might be attributed to the differential expression of alpha 1(I) and alpha 2(I) gene and might also be due to the expression of a different gene for type I trimer collagen.

Metastatic capacity and differentiation in murine melanoma cell lines. A morphometric study

A morphometric analysis was carried out on electron micrographs of cells of the F1 (low metastatic capacity) and F10 (high metastatic capacity) variant sublines of the murine B16 melanoma, both in in-vitro cultures and in lung-metastatic nodules developed after the intravenous injection of neoplastic cells in syngeneic C57 black male mice. A group of 28 morphometric parameters was derived to describe quantitatively each neoplastic cell profile. No qualitative difference was observed between the two cell lines. The quantitative expression of subcellular organelles was dissimilar in the two sublines, being consistently characterized, both in in-vitro cultured cells and in lung-metastatic colonies, by a significant decrease in the mean values of parameters related to melanosomes in the high metastatic capacity cell line (B16-F10). Moreover, in in-vitro cultured cells, indices describing heterochromatin masses and cytoplasmic membranous compartments displayed statistically significant differences between the two sublines. In this experimental system, an inverse relationship between metastatic capacity and differentiation is detected, since cells with a more aggressive metastatic behavior exhibit a decreased degree of differentiation.

Studies on the intracellular degradation of newly synthesized collagen in 3-methylcholanthrene induced fibrosarcoma cells

The intracellular degradation of newly synthesized collagen was studied in both normal fibroblast and 3-methylcholanthrene induced fibrosarcoma cells. The degradation of newly synthesized collagen was examined using pulse-chase experiments and radioactive labelling techniques with [3H]-proline. The percentage of intracellular proteolysis of newly synthesized collagen was determined by measuring the formation of [3H]-hydroxyproline containing fragments in alcohol-soluble and insoluble fractions of normal cells and fibrosarcoma cells in the culture. The rate of degradation of newly formed collagen was then followed by estimating the radioactivity of [3H]-hydroxyproline at different intervals, during the chase period. The results clearly demonstrated that the percent of intracellular degradation of newly synthesized collagen was approximately three fold higher in fibrosarcoma cells than in normal fibroblast cells. The increased intracellular degradation of newly formed collagen was followed by an increase in the activity of cathepsin B and L in fibrosarcoma cells. The pulse-chase experiments indicated that the rate of degradation of newly synthesized collagen in fibrosarcoma cells is relatively greater than in normal fibroblast cells. In addition, as the labelling time increased, the formation of [3H]-hydroxyproline containing peptides in the ethanol-soluble fraction were found to be increased in both normal cells and fibrosarcoma cells, but the extent of formation was higher in fibrosarcoma cells compared to normal fibroblast cells. The results of this investigation collectively suggest that the intracellular degradation of newly synthesized collagen is enhanced in fibrosarcoma cells.

Fibroblastlike primary cells from human colon adenocarcinoma explants: collagen biosynthesis

Fibroblastlike primary cells have been obtained from human colon adenocarcinoma explants. Such cells disappear during cell culture and thus have not been previously studied. These cells have a number of altered phenotypic characteristics: a) morphology; b) growth behavior and adherence to culture substrate (they required 3 h for 90% attachment and only presented a flattened morphology 40 h after platting); and c) collagen metabolism. Increased protein biosynthesis (about double than control colon-derived fibroblasts) and maintained ability for collagen biosynthesis have been observed for the tumor-associated fibroblastlike cells. Thus, the collagen to noncollagenous proteins ratio was decreased for these cells. They exhibited an altered type I:type III collagen (5:1 instead of 3:1 in colon fibroblasts) and procollagen (2:1 against 5:1 in colon fibroblasts) ratios as well as a decreased secretion of collagen with an abnormal deposition of procollagens in the cell layer. These studies show a permanent phenotypic alteration in the tumor-associated fibroblast-like cells.

Localization of type IV collagen in the basement membranes of human prostate and lymph nodes by immunoperoxidase and immunoalkaline phosphatase

The object of these studies was to examine the localization of type IV collagen (Coll-IV) in the basement membranes (BM) of epithelial and stromal elements (smooth muscle, nerves, vessels) in normal, hyperplastic, and neoplastic (primary and metastatic) prostate. We also examined the relationship of Coll-IV distribution to the degree of tumor differentiation (Gleason grading system). We compared immunoperoxidase (IP) and immunoalkaline phosphatase (AP) techniques in these studies and in selected samples we also evaluated immunofluorescence (IF) localization of Coll-IV and the effects of tissue fixation and pepsin digestion. We found that IF localization of Coll-IV was intense in unfixed sections. IP and AP reactions were absent in fixed, paraffin-embedded sections but pepsin treatment yielded intense and uniform reaction products in these same preparations. Both the IP and AP techniques showed similar localization of Coll-IV in the BM of normal, hyperplastic, and well-differentiated tumor. In most of the higher-grade tumors Coll-IV localization was reduced and a similar pattern of distribution was observed after IP and AP techniques. However, in some high-grade tumors the IP technique showed good localization but AP did not, and vice versa. Such discrepancies were noted in the BM of the tumor cells, as well as in the BM of the stromal elements and in lymph nodes with metastatic tumor. Thus, our study shows decreased Coll-IV localization in higher-grade tumors and suggests that the use of a single technique (IP or AP) may exaggerate this apparent loss of Coll-IV BM components. The exact cause of these discrepancies is unknown but they must reflect variable losses in the ability of the tumor cells to form BM, degradation or decreased synthesis of BM components by high-grade tumors, or a combination of the above.

Quantitative evaluation of melanoma cell invasion in three-dimensional confrontation cultures in vitro using automated image analysis

Tumor invasion is a crucial feature of tumor growth in vivo. Confrontation cultures of multicellular melanoma spheroids and embryonic chick heart fragments provide a model for invasive growth in vitro. We have developed an image analysis method, which facilitates the objective measurement of tumor cell invasion in this model. Cryostat sections of confrontation cultures were immunohistochemically stained with an antiserum directed against the stromal component for automated recognition of the stroma tissue. The slides were automatically processed by a grey level based computerized image analysis system. On Spearman's rank correlation test, 25 out of 39 parameters correlated with the reference value of invasion, which was derived from the subjective evaluation of five independent observers. Two parameters combining the stroma margin and the total amount of stroma tissue completely reproduced the judgement of the morphologists in our test set. The quantitative evaluation of tumor invasion in vitro by automated image analysis may be helpful in pharmacologic and pathogenetic studies of tumor growth.

Vascular architecture of melanocytic skin tumors. A quantitative immunohistochemical study using automated image analysis

The present study examines the distribution of blood vessels in melanocytic skin tumors. Fresh frozen sections of 11 cases each of benign nevocellular nevus, primary malignant melanoma and metastatic malignant melanoma were stained with the endothelium-specific monoclonal antibody BMA 120 and evaluated by an automated image analysis system. Additionally, the proliferative activity was assessed in parallel sections using Ki 67 monoclonal antibody. There were only slight differences between the diagnostic groups as to the vascular distribution in the tumor center, but there were remarkable differences in the connective tissue at the base of the lesions: The area occupied by small vessels (minimum diameter less than 20 microns) was 0.3 +/- 0.05% in benign nevi, 0.6 +/- 0.05% in primary malignant melanoma, and 1.2 +/- 0.10% in metastatic malignant melanoma (U-test: p less than or equal to 0.05). The proliferative activity within each lesion showed a strong positive correlation with the number of small vessels at the base of the tumor (linear regression analysis: r = 0.86; p less than or equal to 0.0001). The findings demonstrate that neovascularization in malignant melanocytic tumors takes place predominantly in the surrounding host tissue and is closely related to the proliferative activity.

Collagen metabolism in human colon adenocarcinoma

The collagen metabolism has been studied in a human colonic adenocarcinoma. The overall collagen content was decreased in the tumor. The internal layers of the tumor tissue have the lower collagen content. Stroma cells and epithelial transformed cells, obtained from colon adenocarcinoma explants, were "in vitro" cultured in order to explain the decreased collagen content in the tumor. Cells from the epithelial lineage (both round-shape cells, and those derived from them, epithelial-like cells) showed an almost negligible ability for collagen synthesis. Stroma cells (fibroblast-like cells) maintained a normal ability for collagen biosynthesis but exhibited a 2-fold increased non-collagenous protein synthesis as well as a decreased collagen secretion, when compared with control fibroblasts from non-affected colon regions. The alterations in the stroma cells are not due to soluble factors produced by adenocarcinoma cells. Thus, the fibroblast-like cells, which have been studied for the first time, would be related to the alterations of the extracellular matrix contributing to the invasiveness of the tumor cells.

Membrane association of the hyaluronate stimulatory factor from LX-1 human lung carcinoma cells

LX-1 human lung carcinoma cells interact with human fibroblasts in culture to cause an increase in hyaluronate production (Knudson et al: Proceedings of the National Academy of Sciences of the United States of America 81:6767, 1984). It is shown here that a similar increase in hyaluronate production also occurs when membranes derived from LX-1 cells, or detergent extracts thereof, are added to cultures of the human fibroblasts. However, no stimulation occurs when membranes or extracts from fibroblasts are added to cultures of the LX-1 cells. The hyaluronate stimulatory factor present in the detergent extracts is a heat- and trypsin-sensitive protein, requires more than 12 h for its action on fibroblasts, causes an elevation in hyaluronate synthetase activity in membranes derived from the fibroblasts, and can be reconstituted into artificial lipid vesicles. Thus, it is concluded that the stimulatory factor is a membrane-bound protein present on the surface of the LX-1 cells and that it interacts with fibroblasts to induce increased hyaluronate synthesis.

What's new in the ultrastructure of tumor invasion in vivo?

An important point emerging from the literature on tumor invasion in vivo is the great variability of nearly all aspects studied. It seems that there is neither one particular morphologic change which renders a cell invasive, nor one particular mechanism by which a cell crosses the boundaries of its original tissue compartment to occupy another. Nevertheless, some general trends are demonstrable. The majority of invasive tumor cells appear to be characterized by prominent surface protrusions, decreased junctional contacts and, in the case of epithelium-derived tumor cells, an incomplete basement membrane. The fact that some tumors can invade foreign tissues without loosing their basement membrane is emphasized. Invasive cells frequently form organized associations with preexistent non-neoplastic cells without damaging them. Apparently, the eventual disappearance of the preexistent cells in most invaded tissues is not necessarily due to a direct action on the part of the tumor cells. It rather seems a secondary phenomenon caused by, e.g., the insertion of invasive tumor cells between the preexistent cells and their original stroma. Very often, this seems to be due to the affinity of malignant cells for basement membranes. In addition, the adhesion of tumor cells to basement membranes frequently seems to determine their pattern of spread through a tissue. A process which may turn out to be a key factor in tumor invasion is desmoplasia, the series of host reactions which creates a new environment for the tumor cells which may favor their survival, proliferation, and locomotion. With the rapid development of new techniques, electron microscopy will probably contribute to the elucidation of the exact nature, the degree of similarity to granulation tissue, and the influence on invasion of desmoplastic tumor stroma.

Cellular heterogeneity. Explanation for changing of tumor phenotype and biologic behavior in soft tissue sarcomas

Many human soft tissue sarcomas are known to show variable structures in a given tumor and to be able of changing the histological feature during the course of the disease. These facts prompted an experimental study in order to ascertain if by use of long-term cultures of an established rat fibrosarcoma cell line (RFS) in respective inoculation tumors a histological picture different from the original fibrosarcoma could be produced. It was found that inoculation tumors generated by later subcultures partly corresponded to tumors with features of malignant histiocytomas and malignant fibrous histiocytomas. In a further experiment we attempted to initiate metastatic dissemination of a primarily non-metastasizing xenotransplanted RFS sarcoma in nude mice. By repeated diminution operations comparable to inadequate tumor surgery in human metastasis formation in lung parenchyme was attained. Taking into account cellular heterogeneity as basically responsible for the phenomena observed, different causal aspects concerning the experimental results are discussed. We deduce from our findings that the concept of histogenetic classification of soft tissue sarcomas should be replaced by an interpretation according to the actual differentiation. This also applies to malignant fibrous histiocytomas which are at least in part mesenchymal tumors and not descendants of mononuclear phagocytic cells and may originate by a dedifferentiation process of otherwise defined sarcoma types.

The extracellular matrix of the central and peripheral nervous systems: structure and function

The extracellular matrix (ECM) is the naturally occurring substrate upon which cells migrate, proliferate, and differentiate. The ECM functions as a biological adhesive that maintains the normal cytoarchitecture of different tissues and defines the key spatial relationships among dissimilar cell types. A loss of coordination and an alteration in the interactions between mesenchymal cells and epithelial cells separated by an ECM are thought to be fundamental steps in the development and progression of cancer. Although a substantial body of knowledge has been accumulated concerning the role of the ECM in most other tissues, much less is known of the structure and function of the ECM in the nervous system. Recent experiments in mammalian systems have shown that an increased knowledge of the ECM in the nervous system can lead to a better understanding of complex neurobiological processes under developmental, normal, and pathological conditions. This review focuses on the structure and function of the ECM in the peripheral and central nervous systems and on the importance of ECM macromolecules in axonal regeneration, cerebral edema, and cerebral neoplasia.

Aminoterminal propeptide of type-III procollagen in serum--an indicator of clinical behavior of advanced ovarian carcinoma?

In ovarian carcinoma, elevated serum concentrations of the aminoterminal propeptide of type-III procollagen are related to the clinical stage of the disease and to the presence of ascites, which contains very high concentrations of the propeptide. In a follow-up of patients with advanced disease, favorable clinical course was associated with normalizing propeptide values, whereas in progressing disease the values increased several weeks before clinical progression. In stable disease the concentrations were constantly above the reference range. Laminin and type-IV-collagen-related serum antigens were mostly within the reference range.

Partial characterization of a soluble mitogenic factor from medulloblastoma

To determine how medulloblastoma cells might influence the proliferation and phenotype of normal stromal cells, normal human leptomeningeal cells were treated in culture with medulloblastoma-conditioned medium; their ability to incorporate tritiated thymidine and synthesize collagen was measured. The treated leptomeningeal cells had a significantly greater uptake of tritiated thymidine and grew faster than control leptomeningeal cells. Immunofluorescence studies demonstrated a greater intensity of staining for procollagen type III in the cell layer of the treated cultures than in control cultures; diethylaminoethyl (DEAE)-cellulose chromatography of the medium showed that the treated cells synthesized predominantly type III collagen, whereas control cells synthesized type I collagen. Analysis of the medulloblastoma-conditioned medium revealed that the soluble factor responsible for these effects in an acid- and heat-stable protein. The increased proliferation and altered collagen synthesis induced in leptomeningeal cell cultures by a soluble factor from a medulloblastoma are examples of how tumor and stromal elements interact, and may be related to the process of desmoplasia often observed in medulloblastomas in vivo.

Ultrastructural evidence of collagenolytic activity in ductal infiltrating carcinoma of the human breast

The stroma of ductal infiltrating carcinoma of the human breast shows characteristic and localized areas of collagen rarefaction and fragmentation. This finding has been correlated with a peculiar type of fibrillar damage, observed in a small percentage of collagen fibrils isolated in the native state from the tumour stroma. The same pattern of lesion has been reproduced in vitro by human collagenase digestion on reconstituted fibrils. No effect has been detected by other nonspecific proteases in the same system.

Altered collagen in colonic polyps

By biochemical analysis the molar ratio between hydroxyproline and hydroxylysine as indicator of collagen type were analyzed in normal colons, colonic polyps and carcinomas. Low ratios (type IV) were found in the polyps.