Antisense RNA inhibition of cathepsin L expression reduces tumorigenicity of malignant cells.

Several tumour-forming cell lines are known to overproduce the lysosomal cysteine peptidase cathepsin L. We have used an antisense approach to investigate whether inhibition of cathepsin L overexpression in two malignant cell lines (myeloma SP cells and L cells) reduces their tumorigenic potential. Two different cDNA fragments of murine cathepsin L were inserted in the antisense direction into the pcDNA3 vector, and SP and L cells were stably transfected with these plasmid constructs. Several of the selected clones expressing the antisense transcript showed specific reduction of the mRNA level and the intracellular activity of cathepsin L, and a greatly diminished amount of secreted procathepsin L. When tested in Balb/c nu/nu mice, the cell lines with low cathepsin L activity exhibited a significantly decreased potential for tumour growth when compared with control cells expressing wild-type levels of cathepsin L activity. This observation suggests that cathepsin L is a critical factor in tumour growth.

Expression of cell-cycle proteins p53, p21 (WAF-1), PCNA and Ki-67 in benign, premalignant and malignant skin lesions with implicated HPV involvement.

A series of 120 biopsies from benign (verruca vulgaris and keratoacanthoma), premalignant (actinic keratosis and extragenital Bowen's disease) and malignant (squamous cell carcinoma) skin lesions were studied immunohistochemically for the expression of cell-cycle proteins p53, p21 (WAF-1), PCNA and Ki-67. The presence of human papillomavirus (HPV) DNA in these samples had been analysed previously using in situ hybridization (ISH) and PCR. Moderate to intense expression of both PCNA and Ki-67 was present in most of the lesions studied. PCNA staining was extensive in the epidermis underneath the layers where abundant HPV DNA staining was shown in HPV DNA-positive verrucas. In keratoacanthomas, p21 and PCNA expression remained low, despite intense p53 expression. In actinic keratosis, only half of the specimens showed overexpression of p53 associated with moderate or intense expression of PCNA. In extragenital Bowen's lesions, all these cell-cycle markers were overexpressed, but in squamous cell carcinomas, they were heterogeneously expressed and showed no correlation with tumour differentiation. Our results suggest a mechanism by which HPV can reactivate the host genes (leading to cell proliferation) to support its own DNA replication. Also p21 might start keratinocyte differentiation in areas where HPV DNA replication starts. Cell proliferation remained active in actinic keratosis and Bowen's lesions, emphasizing the precancer character of these lesions in contrast with the benign nature of keratoacanthoma and verruca vulgaris.

The role of low resistance blood flow pathways in the pathogenesis and healing of venous leg ulcers.

In an attempt to clarify the pathophysiology of haemodynamics in legs with venous ulcer we investigated the effect of a single intermittent pneumatic compression treatment on the peripheral resistance of leg arteries and the cutaneous laser Doppler flux in the leg. Eight patients with venous leg ulcers and 10 subjects with healthy legs were investigated. Doppler waveforms of the leg arteries and laser Doppler flux of the leg skin were recorded before and after a single intermittent pneumatic compression treatment with the subjects in a recumbent position. In the legs with venous ulcer, the peripheral resistance of the arteries was lower and the laser Doppler flux was greater, compared with healthy legs (p = 0.003 and p = 0.002, respectively). A single intermittent pneumatic compression treatment raised the peripheral resistance in the arteries of legs with ulcer and laser Doppler flux of the skin more in ulcer legs than in healthy legs (p = 0.046 and p = 0.034, respectively). These findings suggest that removal of oedema causes redistribution of skin blood flow in the legs with venous ulcer favouring the superficial capillary perfusion. This could explain why compression treatment promotes the healing of venous leg ulcers.

The peripheral resistance in arteries of legs is inversely proportional to the severity of chronic venous insufficiency.

There are conflicting reports in the literature about the existence of arteriovenous shunting in legs with chronic venous insufficiency. Using duplex scanning, we have earlier shown that there is lowered peripheral resistance in the arteries of legs with venous ulcer together with premature venous filling in angiography. In the present study we investigated the peripheral resistance in the arteries of 16 legs with chronic venous insufficiency without present ulcer. We compared the results with those obtained from 12 healthy legs and from 18 legs with venous ulcer. There was a highly significant inverse correlation between the severity of chronic venous insufficiency and the peripheral resistance in the popliteal, the dorsal pedal and the posterior tibial arteries (p < 0.001). These results suggest that there is arteriovenous shunting in legs with chronic venous insufficiency and that this phenomenon correlates with the degree of chronic venous insufficiency.

Expression of PCNA is associated with the presence of HPV DNA in skin warts.

A series of 90 excised cutaneous warts (verrucae vulgaris) were studied for the presence of HPV (human papillomavirus) DNA using in situ hybridization (ISH) with biotinylated full genomic DNA probes of HPV types 1, 2, 3, and 4. The expression of PCNA (proliferating cell nuclear antigen) was examined using conventional immunohistochemistry. The aim was to test the hypothesis that HPV can reactivate PCNA, including in the host replication machinery. HPV DNA of the above types was detected in 60 of 90 verruca biopsies studied (66.7%): HPV 2 in 56 cases, HPV 1 in 2 cases, and HPV 3 in 2 cases. PCNA was expressed in all samples except two. The signal distribution of HPV DNA markedly differed from that of PCNA expression. ISH revealed strong HPV DNA signals in both the granular and the upper spinous cell layers, the most intense signals being detected in the upper epidermis. On the other hand, nuclear PCNA staining was present in the majority of parabasal and basal cells. Although strong PCNA signals within the wart lesions were found in the areas where HPV DNA was present, the PCNA positivity was almost invariably localized in the differentiated cells of the spinous cell layers, just below the HPV DNA-expressing cells. At the margins of the lesions, PCNA expression was still strong but disappeared abruptly towards the normal epidermis. HPV DNA-positive warts showed more intense expression of PCNA than did the HPV DNA-negative ones in this study. Our results indicate that PCNA induction is associated with the presence of HPV DNA, suggesting that HPV can reactivate PCNA, thus interfering with the host cell DNA replication machinery.

Failure to demonstrate human papillomavirus (HPV) involvement in Bowen's disease of the skin.

To assess the role of human papillomavirus (HPV) in the aetiology of extragenital Bowen's disease (EBD), a series of 91 cases were analysed using in situ hybridization (ISH) with whole genomic DNA probes of HPV types 1, 2, 4, 6, 7, 11, 12, 15, 16, 18, 26, 36, 37, 39, 42, 55 and 59. No HPV DNA was found in any of the samples tested. A polymerase chain reaction (PCR) was also used to analyse 37 of the 91 samples, using both the consensus primers MY09/MY11 which amplify a large number of HPV types from the L1 region and the degenerate primers CP65/CP70, which amplify the complete set of epidermodysplasia verruciformis (EV) HPV types. All the cases were also negative in the PCR. The results suggest that EBD is not HPV-related, at least in immunocompetent patients.

Known HPV types have no association with keratoacanthomas.

Certain HPV types have been linked to the genesis and development of premalignant and malignant skin diseases. There have been several contradictory reports on the role of HPV infections in the development of keratoacanthomas (KAs). To further study the involvement of HPVs in the aetiology of KAs, we investigated paraffin-embedded specimens of 80 biopsies of KAs for the presence of HPV 1, 2, 3, 4, 5, 7, 26, 37, 38, 47 and 59 DNA by in situ hybridization (ISH) with biotinylated probes under high stringency conditions (Tm-10 degrees C). Every fourth biopsy specimens was also examined by polymerase chain reaction (PCR) with consensus primers targeting the HPV E1 and L1 regions. The positive cases were further studied by direct DNA sequencing. All specimens proved to be negative for all HPV DNAs studied by ISH. Three out of 20 cases produced in positive PCR amplifications when consensus primers targeting the L1 region were used. However, the same samples remained negative with general primers targeting the E1 region. The DNA sequence analysis of the PCR-positive products showed a 76% homology with HPV type 17. Our results suggest that the known HPV types are unlikely to have any role in the aetiology of KAs.

Expression of acid cysteine proteinase inhibitor (ACPI) in the normal human prostate, benign prostatic hyperplasia and adenocarcinoma.

Acid cysteine proteinase inhibitor (ACPI or cystatin A) is a protein (12 kDa) which inhibits the action of several cysteine proteinases, e.g. cathepsins B, H, L and S. In this study the cellular location of ACPI has been immunohistochemically investigated in the normal human prostate, in benign prostatic hyperplasia (BPH) and in adenocarcinoma. ACPI was found in the basal epithelial cells of the normal prostate. The secretory epithelial cells did not express ACPI. In the hyperplastic prostate, the expression of ACPI was decreased and it was also expressed more focally in the basal cells. Hyperplastic basal cells also expressed ACPI. In prostatic adenocarcinoma, no ACPI expression was found. The absence of ACPI expression was obvious and if the sections contained both benign and malignant cells, only the benign glandular structures always expressed ACPI. The results suggest that expression of ACPI might be related to prostatic epithelial cell proliferation and differentiation. Possibly the detection of ACPI in tissue sections might be helpful in identifying prostatic adenocarcinoma, especially in cases with small carcinomatous foci.

Acid cysteine proteinase inhibitor in cutaneous lymphocytic infiltrates.

Acid cysteine proteinase inhibitor (ACPI, cystatin A) is normally present in squamous epithelium and dendritic cells of lymphoid follicles. Its expression is altered both in proliferative and malignant squamous epithelium and in neoplastic lymphoid follicles. The expression of ACPI in the lymphoid infiltrates of cutaneous psuedolymphomas and B-cell lymphomas was studied. Eighteen pseudolymphomas from 15 patients were divided into three groups according to the proportion of B and T lymphocytes. The B-cell-type lesions with well-developed follicles and germinal centers showed a pronounced ACPI expression in dendritic cells. Varying amounts of ACPI-positive cells were present in the mixed B- and T-cell-type and also in the T-cell-type lesions. The labeled cell population was distinct from the factor XIIIa-positive dermal dendrocytes, S-100-positive histiocytes, and HAM 56-positive histiocytes. Malignant lymphomas contained a few haphazardly arranged ACPI-positive cells with short dendrites and granular cytoplasm. It was concluded that follicular dendritic cells can be reliably labeled with ACPI antiserum in cutaneous pseudolymphomas. The structure and distribution of ACPI-containing cells in malignant cutaneous B-cell lymphomas is altered when compared with pseudolymphomas.

No evidence of human papillomavirus DNA in actinic keratosis.

Human papillomaviruses (HPVs) are involved in premalignant and malignant skin diseases as well as in a variety of benign cutaneous and mucosal lesion disease. Its association with HPV infection has recently been evaluated in a few studies, but the results are contradictory. For further assessment of the role of HPVs in AK, a series of 100 paraffin-embedded biopsy specimens taken from subjects with AK were studied for the presence of HPV types 1, 2, 3, 4, 5, 7, 12, 15, 26, 36, 37 and 59 DNA using in situ hybridization (ISH) under high stringency conditions (Tm -10 degrees C). All specimens were definitely negative for all bion specimens were definitely negative for all biotinylated HPV DNA probes tested. One fifth of the specimens were studied using the polymerase chain reaction (PCR) with general primers to confirm the negative results. All cases were also in the PCR. Our results suggest that HPVs are not directly involved in the aetiology of AK.

Identification of acid cysteine proteinase inhibitor (cystatin A) in the human thymus.

BACKGROUND: Acid cysteine proteinase inhibitor (ACPI, also called cystatin A) is a protein that is present in the epithelial cells of the skin and in the dendritic reticulum cells of lymphoid tissues. In this study the presence and cellular localization of ACPI in the thymus was investigated. METHODS: The cellular and topographical location of ACPI was immunohistochemically demonstrated in the normal thymus of man. RESULTS: ACPI was found in the cells of the Hassall's corpuscles and in many medullary cells. Most of these cells were epithelial cells, as shown by the results of immunohistochemical cytokeratin and epithelial membrane antigen stainings. Also, some individual cytokeratin negative but S-100 positive medullary reticular dendritic cells were stained with ACPI. CONCLUSIONS: The finding that ACPI is constantly present in the thymus at restricted and specific cellular locations leads to the suggestion that protease inhibitors may play a role in specific thymic functions.

An inactive cathepsin B-like enzyme and cysteine proteinase inhibitors in colon cancer ascites.

The ascitic fluid of a patient with colon cancer was found to contain an inactive cathepsin B-like enzyme. The inactive enzyme with a molecular weight of 40 kDa was converted by pepsin treatment into an active form with a molecular weight of 28 kDa as revealed by Sephadex G-75 gel chromatography. The inactive cathepsin B-like enzyme was considered to represent a precursor form and not an enzyme-inhibitor complex. The activated cathepsin B-like enzyme resembled human liver cathepsin B in its enzymatic characteristics. Cysteine proteinase inhibitor activity was also detected in the same ascitic fluid, and it was separated into two main forms by Sephadex G-75 gel chromatography. The high molecular weight inhibitor fractions reacted with antiserum against alpha-CPI and the low molecular weight fractions reacted with antiserum against cystatin B.

Inactive cathepsin B-like enzyme in human melanoma culture medium.

An inactive cathepsin B-like enzyme with a molecular mass of 40 kD was found in a human melanoma culture medium. The inactive form of this enzyme was converted into an active form with a molecular mass of 28 kD by pepsin treatment. This activated cathepsin B-like enzyme had almost the same characteristics regarding molecular size, substrate specificity, dependence on chemical reagents, and Km values as intracellular cathepsin B. Sodium dodecylsulphate polyacrylamide gel electrophoresis followed by electroblotting with an antiserum against cathepsin B yielded inactive cathepsin B-like enzyme fractions which showed two immunoreactive bands with molecular masses of 40 and 28 kD, respectively. On the other hand, alkali treatment of the inactive cathepsin B-like enzyme fractions released a cysteine proteinase inhibitor with a molecular mass of 12 kD. These data suggest that these inactive cathepsin B-like enzymes in melanoma culture medium are present not only in the precursor form, but that they are also present as enzyme-inhibitor complexes, both of which can be activated enzymatically in vitro.

Purification and characterization of a cystatin-type cysteine proteinase inhibitor in the human hair shaft.

We found a cysteine proteinase inhibitor in human hair shaft extract treated with 0.01 M Tris HCl buffer, pH 8.0. A yield of 0.2 mg of purified cysteine proteinase inhibitor was obtained from 86 g of hair shaft. The cysteine proteinase inhibitor had a molecular mass of 13 kDa as determined by high-performance liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. It was more stable to heat and pH than most proteins and had a pI of 4.7. Immunologically, its antigenicity was the same as that of cystatin A, but differed from that of cystatin B and C, and kininogen. The amino-acid sequence of the first 30 residues from the NH terminus of the inhibitor was identical to that of cystatin A from human epidermis. Hair shaft cysteine proteinase inhibitor is thus considered to be identical to epidermal cystatin A.

Immunolocalization of cystatin A in neoplastic, virus and inflammatory lesions of the uterine cervix.

Cystatin A was immunohistochemically demonstrated in the normal squamous epithelium of the uterine cervix, particularly in the parabasal and superficial cell layers whereas it was absent or scanty in the basal cells and in areas with parakeratosis. Cystatin A was also found in neoplastic lesions (dysplasia, carcinoma in situ and squamous cell carcinoma), but less abundant than in normal squamous epithelium. The immunoreaction in intraepithelial neoplasia was closely related to the degree of morphological maturation of the squamous cells with more abundant cystatin A in low grade dysplasia and less in high grade dysplasia and carcinoma in situ. In squamous cell carcinoma, cystatin A was often abundant in highly differentiated areas and almost absent in poorly differentiated ones. Cystatin A was found in the squamous epithelium in herpes and in condylomatous lesions. It was also found in the cytoplasm of neutrophils, but not in lymphocytes and plasma cells. In unspecific cervicitis, cystatin A was found extracytoplasmatically as small vesicles in the epithelial-stromal junction. The implications of cystatin A in neoplastic, virus, and inflammatory processes are discussed.

Ultrastructural signs of altered intracellular metabolism in acral persistent papular mucinosis.

An asymptomatic 24-year-old woman presented with multiple discrete papules on the extensor surfaces of the hands and wrists. Light microscopy revealed focal increase in the amount of dermal fibroblasts as well as deposition of hyaluronidase-labile mucoid substance. The collagen and elastin were decreased. The changes were consistent with acral persistent papular mucinosis (APPM). In electron microscopy, the intercellular glycosaminoglycans showed small ruthenium red-positive granules and thin filaments indicating normal morphology. The fibroblastic cells, however, were conspicuously altered. Endoplasmic reticulum was dilated, cytoplasm contained large amounts of osmiophilic, concentric lysosomal structures, and there was distinct fibrous lamina in the nuclear membrane. It was concluded that the primary event in APPM probably affects the intracellular metabolism of the dermal fibroblast. The accumulation of lysosomal structures may be a distinct feature of APPM differentiating it from the other reactive cutaneous mucinoses, or it may only reflect nonspecific degeneration in a long-standing lesion.