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Myoferlin: A Potential Marker of Response to Radiation Therapy and Survival in Locally Advanced Rectal Cancer.

PURPOSE: Patients with locally advanced rectal cancer often require neoadjuvant chemoradiation therapy to downstage the disease, but the response is variable with no predictive biomarkers. We have previously revealed through proteomic profiling that myoferlin is associated with response to radiation therapy. The aims of this study were to further validate this finding and explore the potential for myoferlin to act as a prognostic and/or therapeutic target. METHODS AND MATERIALS: Immunohistochemical analysis of a tissue microarray (TMA) for 111 patients was used to validate the initial proteomic findings. Manipulation of myoferlin was achieved using small interfering RNA, a small molecular inhibitor (wj460), and a CRISPR-Cas9 knockout cell line. Radiosensitization after treatment was assessed using 2-dimensional clonogenic assays, 3-dimensional spheroid models, and patient-derived organoids. Underlying mechanisms were investigated using electrophoresis, immunofluorescence, and immunoblotting. RESULTS: Analysis of both the diagnostic biopsy and tumor resection samples confirmed that low myoferlin expression correlated with a good response to neoadjuvant long-course chemoradiation therapy. High myoferlin expression was associated with spread to local lymph nodes and worse 5-year survival (P = .01; hazard ratio, 3.5; 95% CI, 1.27-10.04). This was externally validated using the Stratification in Colorectal Cancer database. Quantification of myoferlin using immunoblotting in immortalized colorectal cancer cell lines and organoids demonstrated that high myoferlin expression was associated with increased radioresistance. Biological and pharmacologic manipulation of myoferlin resulted in significantly increased radiosensitivity across all cell lines in 2-dimensional and 3-dimensional models. After irradiation, myoferlin knockdown cells had a significantly impaired ability to repair DNA double-strand breaks. This appeared to be mediated via nonhomologous end-joining. CONCLUSIONS: We have confirmed that high expression of myoferlin in rectal cancer is associated with poor response to neoadjuvant therapy and worse long-term survival. Furthermore, the manipulation of myoferlin led to increased radiosensitivity in vitro. This suggests that myoferlin could be targeted to enhance the sensitivity of patients with rectal cancer to radiation therapy, and further work is required.

Humans↗

213Bi-PAI2 conjugate selectively induces apoptosis in PC3 metastatic prostate cancer cell line and shows anti-cancer activity in a xenograft animal model.

A novel alpha-particle emitting ((213)Bi) plasminogen activator inhibitor type 2 construct, which targets the membrane-bound urokinase plasminogen activator on prostate cancer cells, was prepared and evaluated in vitro and in a xenograft animal model. The PC3 prostate cancer cell line expresses urokinase plasminogen activator which binds to its receptor on the cell membrane; plasminogen activator inhibitor type 2 is bound to urokinase plasminogen activator/urokinase plasminogen activator receptor to form stable complexes. In vitro, the cytotoxicity of (213)Bi-plasminogen activator inhibitor type 2 against prostate cancer cells was tested using the MTS assay and apoptosis was documented using terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labelling (TUNEL) assay. In vivo, antiproliferative effects for tumours and prostate cancer lymph node metastasis were carried out in an athymic nude mouse model with a subcutaneous xenograft of PC3 cells. (213)Bi-plasminogen activator inhibitor type 2 was specifically cytotoxic to PC3 cells in a concentration-dependent fashion, causing the cells to undergo apoptosis. A single local or i.p. injection of (213)Bi-plasminogen activator inhibitor type 2 was able to completely regress the growth of tumours and lymph node metastases 2 days post subcutaneous inoculation, and obvious tumour regression was achieved in the therapy groups compared with control groups with (213)Bi-plasminogen activator inhibitor type 2 when the tumours measured 30-40 mm(3) and 85-100 mm(3). All control animals and one of five (20%) mice treated with 3 mCi kg(-1) (213)Bi-plasminogen activator inhibitor type 2 developed metastases in the lymph nodes while no lymphatic spread of cancer was found in the 6 mCi kg(-1) treated groups at 2 days and 2 weeks post-cell inoculation. These results demonstrate that this novel (213)Bi-plasminogen activator inhibitor type 2 conjugate selectively targets prostate cancer in vitro and in vivo, and could be considered for further development for the therapy of prostate cancer, especially for the control of micro-metastases or in minimal residual disease.

Animals↗

The influence of reactivation of the telomerase in tumour tissue on the prognosis of squamous cell carcinomas in the head and neck.

BACKGROUND: The reactivation of the telomerase seems to be an important step in the carcinogenesis of most human cancer types. Cell clones, which express this enzyme, get the ability of indefinite proliferation, means become immortal. METHODS: In this study, 80 patients with squamous cell carcinomas (SSC) in oral cavity, oropharynx, hypopharynx and larynx were recorded prospectively concerning a possible correlation of telomerase activity and clinical and prognostic factors. Telomerase activity was analysed by a modified telomeric repeat amplification protocol (TRAP) assay. RESULTS: In 75% of the tumour tissues the telomerase was demonstrated independently of the localization of the tumour. The known clinical prognostic factors did not show any correlation to the expression rate of the telomerase activity in the tumour tissues. Also, reactivated telomerase did not affect the tumour-dependent survival. Only the number of lymph node metastases was in tendency higher in patients with telomerase-positive tumours. The number and timeframe of local and regional recurrences was not influenced by the telomerase status. CONCLUSIONS: Although telomerase seems to be an important part of the carcinogenesis of SCC our data show that the reactivation of telomerase in tumour tissue did not have any prognostic significance for these tumours. The tendency that tumours with active telomerase developed lymph node metastases in a higher number should be evaluated by further enlarged studies for its clinical relevance.

Carcinoma, Squamous Cell↗

Role of macrophages in restricting herpes simplex virus type 1 growth after ocular infection.

PURPOSE: To investigate the role macrophages play in controlling herpes simplex virus (HSV)-1 replication after infection of the murine cornea. METHODS: Macrophage depletion in selected tissues before or after virus infection was achieved by repeated subconjunctival (SCJ) and/or intravenous (IV) injection of liposomes containing dichloromethylene diphosphonate (L-Cl2MDP). Controls received liposomes containing phosphate-buffered saline (L-PBS). The efficiency of depletion was evaluated by histologic examination. Virus content in infected tissues was determined by standard plaque assay. Delayed-type hypersensitivity (DTH) responsiveness was assessed using the ear-swelling assay. Antibody isotype responses to virus antigens and cytokine production were monitored by enzyme-linked immunosorbent assay. RESULTS: Balb/c mice given SCJ injection of L-Cl2MDP 4 and 2 days before HSV-1 corneal infection were found to have ocular virus titers as much as 10(5)-fold higher than that seen in the L-PBS-treated controls 8 days after infection. When L-Cl2MDP treatment was delayed until 2 and 4 days after infection, virus titers in the eye were analogous to those in the control animals. Subconjunctival and submandibular lymph node macrophages in mice given local (SCJ) L-Cl2MDP pretreatment were profoundly reduced, whereas the number of corneal Langerhans' cells and lymph node dendritic cells remained unchanged. Local L-Cl2MDP pretreatment was associated with significantly reduced DTH responsiveness to HSV-1 antigen, and an alteration in selected antibody isotype production. Depletion of macrophages in the subconjunctival tissue before corneal infection was not accompanied by enhanced virus growth at early times (2 or 4 days) after infection. CONCLUSIONS: Macrophages play an important role in restricting HSV-1 growth after corneal infection. These cells appear to be required for the development of an acquired immune response, presumably by functioning in antigen processing and presentation. The hypothesis that macrophages are major participants in innate immunity to HSV-1 corneal infection was not supported.

Acid Phosphatase↗

[Clinical evaluation of adjuvant radiotherapy and chemotherapy for esophageal carcinoma].

Surgical treatment is the most effective therapy for esophageal carcinoma, and adjuvant radiotherapy and chemotherapy are essential for the improvement of postoperative curability. The recurrence of carcinoma after curative surgery is often observed in the upper mediastinum and cervical portion. Fifty Gy of postoperative prophylactic irradiation has been given routinely and this has suppressed the local recurrence of the disease to a remarkable degree. Metastasis of carcinoma to internal organs was not controlled by radiotherapy. This occurs in the case of undifferentiated carcinoma, severe lymph node metastasis and positive invasion to vessels. Cisplatin, vindesine and bleomycin (DVB) combination chemotherapy and another cisplatin-based chemotherapy have been adapted for postoperative cases such as those in stages II, III and IV with radiotherapy. Cases of stage 0 and I with positive carcinomatous invasion to vessels have been treated reasonably with anti-cancer agents. Before chemotherapy, the anti-cancer activities of the drugs in subrenal capsule assay (SRCA) are tested using resected tumors and prospective clinical trials are being performed.

Animals↗

Correlation between the expression of cyclin A protein and p53 activity in oral squamous cell carcinomas.

Cyclins and wild-type p53 protein are prime cell cycle regulators and may be involved in tumorigenesis. Cyclin A is a late S cyclin and its abnormalities have been reported in several cancers, including oral squamous cell carcinomas. To explore whether aberrant G1/S in p53 mutant tumours leads to increased cyclin A protein in oral squamous cell carcinomas (OSCC), a total of 39 samples were evaluated for the expression of cyclin A and p53 protein by an immunohistochemical method using a labelled polymer assay. These samples comprised two hyperkeratotic and three oral premalignant lesions (two moderate and one severe dysplastic lesions), and 27 OSCC, together with seven healthy controls. The results demonstrated that the cyclin A protein was localized and highly expressed in the nuclei of the tumour cells. Although there was no correlation between cyclin A detection and the local lymph node involvement, a positive correlation was noted between the positivity of cyclin A and p53 protein (p <0.05). The results suggested that cyclin A may contribute to the progression of oral cancer and correlated to some degree with that of the p53 gene activity.

Carcinoma, Squamous Cell↗

[Construction and characterization of a live attenuated Shigella flexneri 2a vaccine strain, sf301 Delta virG and dsbA33G].

Construction and characterization of a live attenuated Shigella flexneria 2a sf301 vaccine strain to prevent the endemic of shigellosis. Using Chinese majority epidemic Shigella flexneri 2a serotype sf301 as the target, p Delta virG, a deletion derivation of the virG gene in the SacB suicide vector pCVD442 and pDsbA33G, an mutant of a disulfide bond catalyst DsbA, replaced its 33 amiano acid Cystine by Glycerin in pCVD442, were used to generate a attenuated mutant strain sf301: Delta virG: DsbA33 G. Its virulence was evaluated by Sereny test, the invasive ability was detected by HeLa cell invasive assay, immunogenicity was detected by immunized Guinea pigs through inoculated guinea pigs' conjunctive sac. Sereny test was negative and HeLa invasive assay showed sf301: Delta virG: DsbA33 G retained partial invasive ability. In contrast to control group, sf301: Delta virG: DsbA33 G could induced significantly high antibody levels of IgA and IgG against sf301 LPS in animal's mucosal lavage fluids and sera in both primary immunization protocol and boosting protocol. The numbers of ASCs in local draining lymph nodes and spleens were significantly higher than control group. The immune response to sf301: Delta virG: DsbA33 G could provide completely protection from the challenge of wild type sf301. sf301: Delta virG: DsbA33 G is a safe and effective oral candidate vaccine to prevent the infection of Shigella strains.

Animals↗

A case of tuberculous pyomyositis that caused a recurrent soft tissue lesion localized at the forearm.

We present the case of a 20-year-old male who had a non-traumatic soft tissue lesion (4 x 3 cm) with recurrent discharge at his right posteromedial antebrachial muscles; the patient underwent surgery twice, and antibiotic therapy was administered, but no cure was achieved with these treatments. The patient underwent surgery at our medical center. There was no history of pulmonary, gastrointestinal, or genitourinary tuberculosis (TB). Due to suspected pulmonary, genitourinary, and gastrointestinal TB, radiography and computed tomography scans were performed, and these studies disclosed no evidence of a primary origin. The erythrocyte sedimentation rate and the results of purified protein derivate testing were normal. We also detected submandibular lymphadenopathy (LAP) (2 x 3 cm) localized at a submandibular site in our patient 4 months after his first visit to our clinic. Smears were stained with Ehrlich Ziehl Neelsen (EZN) stain and culture were grown for Mycobacterium tuberculosis complex (MTC); the samples used for these assays had been obtained by incisional biopsy of the forearm lesion and by aspiration of the submandibular lymph node, and they were found to be MTC-positive. Then, a culture for MTC, derived from an induced sputum sample, was found to be positive, despite the negative results obtained with a sputum smear subjected to EZN staining. According to these results, the primary focus of the tuberculous pyomyositis and the submandibular LAP was the lungs. The lesion and submandibular LAP were both treated successfully by the administration of antituberculous chemotherapy.

Adult↗

Clinical assessment of solid phase immunoadsorbent assay of human prostatic acid phosphatase.

A new solid phase immunoenzyme assay for human prostatic acid phosphatase was tested in clinical practice. Clearly elevated levels of prostatic acid phosphatase (PAP) were found with advancing age and even more so in patients with benign prostatic hyperplasia (BPH). In patients with localized carcinoma of the prostate there was no elevation of levels above those observed in patients with BPH. When lymph node metastases were found at staging lymphadenectomy, the preoperative level of prostatic acid phosphatase was elevated in 7 of 12 cases. Good response to hormone treatment of metastatic carcinoma of the prostate was indicated by decrease of PAP-levels to normal. Rising levels often preceded the clinical manifestation of progression.

Acid Phosphatase↗

Preference of lymphocyte-homing to high endothelial venules in palatine tonsils of musk shrew (Suncus murinus).

We studied the lymphocyte-homing to palatine tonsils of the musk shrew, a new experimental animal originally developed in Japan. The tonsils of the animals have typically high endothelial venules (HEV) in the parafollicular region. The in vivo migration test showed that blood-circulating lymphocytes were able to home to the tonsils through the HEV. The in vitro lymphocyte-HEV binding assay clearly indicated the binding preference of the lymphocytes to be the tonsillar HEV. First, binding of B cells to the tonsillar HEV was seen to a greater extent than that of T cells, which was consistent with the result in the assay of Peyer's patch. Second, binding of lymphocytes from axillar and inguinal lymph nodes was similar to that of lymphocytes from the mesenteric lymph nodes, which differed from the result in the assay of Peyer's patch. These findings suggest that, in the musk shrew, the regulation of lymphocyte-homing through the HEV is different in the tonsil and Peyer's patch, at least in part. These homing properties of musk shrew tonsils may reflect their immunological role in the local response against oral antigens.

Animals↗

Investigation of mammary epithelial cell-bone marrow stroma interactions using primary human cell culture as a model of metastasis.

A model has been established using primary human cell culture to study the cell biology of breast cancer metastasis to bone marrow. Mammary epithelia were obtained in single cell suspension from tumour (macroscopically involved), benign (macroscopically uninvolved) and normal (reduction mammoplasty) breast tissue as well as from locally involved lymph nodes. Stromal layers were generated from long-term cultures of human bone marrow or from mammary fibroblasts derived from normal or malignant tissue. The interaction between epithelia and stroma has been studied in terms of adhesion of the epithelia to the stroma and their subsequent growth in co-culture. Our results show that when assayed up to 9 hr after plating, epithelial cells from malignant tissue (14 primary tumours and 9 metastases in lymph nodes) displayed a significant preference for adhesion to bone marrow stroma compared with mammary fibroblasts. In contrast, epithelial cells from 4 normal and 2 of 4 benign samples showed no significant preferential adherence. Subsequent co-culture of mammary epithelia with each of the 3 stromal layers revealed that under serum-free, in vitro conditions, bone marrow stromal layers did not provide an advantageous environment for colony growth, in contrast to their ability to provide a preferential substratum for adhesion.

Animals↗

Implications of prostate micrometastases in pelvic lymph nodes: an archival tissue study.

OBJECTIVES: In the United States, radical retropubic prostatectomy for adenocarcinoma usually includes a staging pelvic lymphadenectomy. If frozen section analysis of the lymph nodes fails to reveal any evidence of metastases, the prostate is removed. We have previously noted that as many as 56% of patients undergoing radical prostatectomy demonstrate rising serum prostate-specific antigen (PSA) levels by 4 years postoperatively. This report was designed to determine whether micrometastases undetectable by conventional pathologic methods: could have accounted for these biochemical failures. METHODS: A retrospective analysis of formalin-fixed paraffin-embedded pelvic lymph node material was undertaken using a reverse transcription-polymerase chain reaction (RT-PCR)-based assay designed to amplify messenger RNA from PSA. All specimens were obtained from a group of 57 patients with prostate cancer who had undergone staging pelvic lymphadenectomy at the time of radical prostatectomy, and whose long-term follow-up was known. RESULTS: Although all of these nodes appeared to be free of tumor by conventional pathologic methods, a RT-PCR assay was used to identify evidence of prostate metastases in 44% of evaluable samples. Of these, 14 of 16 went on to manifest rising serum PSA values by 5 years postoperatively. CONCLUSIONS: These results suggest that molecular staging of pelvic lymph nodes prior to planned therapy for clinically organ-confined prostate cancer may better distinguish between patients with local disease and those for whom local therapy alone will not be curative. To our knowledge, this is the first large-scale retrospective gene expression study published.

Adenocarcinoma↗

Elevated plasma transforming growth factor-beta 1 levels in breast cancer patients decrease after surgical removal of the tumor.

OBJECTIVE: The authors determined whether untreated breast cancer patients have elevated plasma levels of transforming growth factor-beta 1 (TGF-beta 1). SUMMARY BACKGROUND DATA: Increased plasma TGF-beta 1 levels recently were found after chemotherapy in patients with advanced breast cancer. However, it currently is unknown whether this elevation in plasma TGF-beta 1 is caused by chemotherapy-induced normal tissue damage or whether it results from the presence of the tumor. METHODS: An enzyme-linked immunosorbent assay was used to measure plasma TGF-beta 1 levels in 26 newly diagnosed breast cancer patients before and after definitive surgery. Patients were grouped by postoperative tumor status: 1) negative lymph nodes (group 1); 2) positive lymph nodes (group 2); and 3) overt residual disease (group 3). The site of TGF-beta 1 production in the tumors was localized by immunohistochemistry and in situ hybridization. RESULTS: Plasma TGF-beta 1 levels were elevated preoperatively in 81% of the patients; TGF-beta 2 and TGF-beta 3 were undetectable. The preoperative TGF-beta 1 levels in the three patient groups were similar; however, the postoperative plasma TGF-beta 1 levels differed by disease status. The mean plasma TGF-beta 1 level in group 1 (n = 12) normalized after surgery (19.3 +/- 3.2 vs. 5.5 +/- 1.0 ng/mL, p < 0.001). In contrast, the mean plasma TGF-beta 1 levels remained above normal in both group 2 (n = 9) and group 3 (n = 5) after surgery. Transforming growth factor-beta 1 expression was found to be preferentially increased in the tumor stroma. CONCLUSIONS: Breast tumors result in increased plasma TGF-beta 1 levels in 81% of patients. After surgical removal of the primary tumor, the plasma TGF-beta 1 level normalizes in the majority of patients; persistently elevated levels correlate with the presence of lymph node metastases or overt residual tumor. These findings suggest that the usefulness of TGF-beta 1 as a potential plasma marker for breast tumors deserves further study.

Biomarkers, Tumor↗

[Overexpression of NDRG1: relationship with proliferative activity and invasiveness of breast cancer cell line and breast cancer metastasis].

OBJECTIVE: To investigate the relationship between NDRG1 and metastasis of breast cancer and the effects of NDRG1 overexpression on the proliferation and invasion of breast cancer cells. METHODS: NDRG1 was detected at its protein level by immunohistochemistry (IHC) and its messenger RNA (mRNA) was detected by real-time reverse transcriptase-polymerase chain reaction (real time RT-PCR) in clinical breast cancer specimens. Liposome was used to transiently transfer NDRG1 into MDA-MB-231, a highly invasive human breast cancer cell line. The proliferation of MDA-MB-231 was measured by Bromodeoxy Uridine (BrdU) incorporation assay and the transfection effect on cell cycle distribution was determined by fluorescence assisted cell sorting (FACS). The invasive ability of the transfected cells was investigated by reconstituted matrigel invasion and polycarbonate filters migration experiments. RESULTS: NDRG1 expressions at protein and mRNA levels in tumors of patients with lymph node metastases were significantly lower as compared with those with localized breast cancers (P < 0.01). The amount of NDRG1 mRNA in MCF7, a relatively non-invasive breast cancer cell line, was 10.8 times higher than that in MDA-MB-231 cells (P < 0.01). The BrdU incorporation rate declined significantly (P < 0.05) in NDRG1 overexpressing MDA-MB-231 cells. An increase of the cell population at G(0)/G(1) phase was observed 48 hours post-transfection along with a decrease of cell population at S phase. Overexpression of NDRG1 significantly retarded the invasiveness of MDA-MB-231 cells in matrigel-coated invasion chambers (P < 0.05), when compared to cells transfected with control vectors. However, the migration abilities of cells with or without the transfection were virtually identical. CONCLUSIONS: NDRG1 expression reversely correlates with breast cancer metastasis and progression, and may serve as a prognostic biomarker for predicting early metastasis. The inhibition of proliferation and invasion demonstrated by our MDA-MB-231 transfection experiments implies that NDRG1 is a tumor metastasis suppressor gene and may be a new candidate for gene therapy against human breast cancer.

Breast Neoplasms↗

The in vivo behavior of T cell clones: altered migration due to loss of the lymphocyte surface homing receptor.

Although cloned lines of T lymphocytes have been valuable in defining the in vitro functions of well-defined cell types, they have often demonstrated relatively poor activity in vivo. One striking property of T cells clones which might affect their in vivo activity is their unusual inability to localized in lymphoid tissue as do most normal T cells. Normal lymphocyte recirculation and localization requires that lymphocytes recognize and pass through the walls of specialized high endothelial venules (HEV) as they enter into lymph nodes. We previously showed that murine T cell clones are unable to home into the peripheral lymphoid organs-lymph nodes and Peyer's patches. The inability of these cells to recognize lymph node HEV in an in vitro frozen section adherence assay suggested that the lack of lymphoid homing was due to the loss of a normal lymphocyte surface receptor for HEV. The present experiments were designed to determine: 1) the molecular mechanism responsible for the loss of normal lymphocyte migration, and 2) whether these migration and homing characteristics are irreversible features of T cell clones. Flow cytometric analysis of helper and cytolytic clones using a monoclonal antibody (MEL-14) specific for the lymphocyte homing receptor showed that they lack this surface receptor. This lack of receptor expression was confirmed by the inability to detect the antigen in detergent-solubilized extracts of surface-radiolabeled cells. Thus, the lack of homing to lymph nodes appears to be due to the loss of expression of the surface receptor which mediates the interaction between lymphocytes and HEV. When clones were rested in vitro in a nonproliferative state without stimulation by antigen or growth factors, they did not regain expression of the surface homing receptor or the ability to migrate to lymph nodes in vivo. The lack of receptor expression, therefore, is not merely associated with a rapidly proliferating state, but rather seems to be an irreversible feature of T cell clones, at least under in vitro culture conditions. T cell clones, both rested and recently restimulated, share certain features characteristic of activated T cells, as shown by recent results with MLC-stimulated T cell blasts. Both populations are large, brightly PNA-positive lymphocytes which lack expression of the MEL-14 receptor and do not home to peripheral lymphoid tissue. We propose that this PNA-high, MEL-14- nonrecirculating phenotype may represent a normal phase of T cell differentiation through which many T cells pass after being activated by specific antigen.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Localization of T-cell determinants on bovine beta-lactoglobulin.

T-cell determinants of bovine beta-lactoglobulin (beta-LG) in BALB/c(H-2d), C57BL/6(H-2b) and C3H/He(H-2k) mice were identified using a set of overlapping synthetic peptides encompassing the entire primary structure of the protein. Lymph node cells from mice immunized with beta-LG were subjected to cell proliferation assay in the presence of these peptides and uptake of 3H-labeled thymidine was measured. Determinant regions were indicated to lie in residues 42-56, 62-76 and 139-153 in BALB/c mice, residues 11-26, 72-86, 100-113 and 119-133 in C57BL/6 mice, residues 72-86, 91-104, 129-143 and 139-153 in C3H/He mice. Some of these fragments included the antigenic motifs predicted by hypotheses according to amphipathicity and sequential patterns of peptides. We reported elsewhere that residues 42-56 and 72-86 represent one of the B-cell antigenic determinants in BALB/c and C3H/He, respectively. These peptides serve as good models of colinear T- and B-cell determinants as they contain both of T- and B-cell determinants.

Amino Acid Sequence↗

Structure, function, regulation and clinical significance of the 52K pro-cathepsin D secreted by breast cancer cells.

In estrogen-receptor-positive human breast cancer cell lines (MCF7, ZR75-1), estrogens specifically increase the secretion into the culture medium of a 52,000 Da (52K) glycoprotein and stimulate cell proliferation. The 52K protein has been purified to homogeneity using monoclonal antibodies and identified as the secreted precursor of a cathepsin D bearing mannose-6-phosphate signals. The secreted precursor 52K protein is mitogenic in vitro in estrogen-deprived MCF7 cells, can be taken up by these cells via mannose-6-phosphate receptors, and can degrade extracellular matrix and proteoglycans following its auto-activation. The protease is also produced constitutively by ER-negative cell lines, and is inducible by tamoxifen in some antiestrogen-resistant variants. The corresponding cDNA has been cloned using N-terminal sequencing of the protein and monoclonal antibodies. Its complete sequencing indicates a strong homology with pro-cathepsin D of normal tissues. Using a cDNA probe, the regulation of 52K cathepsin D mRNA by estrogens and antiestrogens has been studied and chromosome localization determined by in situ hybridization. Clinical studies using both immunohistochemistry and immunoenzymatic assay of breast cancer cytosol have shown that the concentration of total cellular cathepsin D (52K + 48K + 34K) is related to the proliferation of mammary ducts and to the prognosis of breast cancer. Its cytosolic concentration in primary tumors of postmenopausal patients is correlated slightly with lymph node invasion and significantly with shorter disease-free intervals in a 6-year retrospective study with the Danish Breast Cancer Groups and Finsen Institute (S. Thorpe et al.).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗

In vitro autoradiographic localization of angiotensin-converting enzyme in sarcoid lymph nodes.

Angiotensin-converting enzyme (ACE) was localized in sarcoid lymph nodes by an in vitro autoradiographic technique using a synthetic ACE inhibitor of high affinity, 125I-labelled 351A. The lymph nodes were from seven patients with active sarcoidosis who underwent mediastinoscopy and from six control subjects who had nodes resected at either mediastinoscopy or laparotomy. Angiotensin-converting enzyme was localized in the epithelioid cells of sarcoid granulomata in markedly increased amounts compared with control nodes, where it was restricted to vessels and some histiocytes. In sarcoid lymph nodes, there was little ACE present in lymphocytes or fibrous tissue. Sarcoid nodes with considerable fibrosis had much less intense ACE activity than the nonfibrotic nodes. The specific activity of ACE measured by an enzymatic assay in both the control and sarcoid lymph nodes closely reflected the ACE activity demonstrated by autoradiography. Sarcoid lymph nodes with fibrosis had an ACE specific activity of half that of nonfibrotic nodes (p less than 0.05). There was a 15-fold increase in specific ACE activity in sarcoid nodes (p less than 0.05) compared to normal. Serum ACE was significantly higher in those sarcoid patients whose lymph nodes were not fibrosed compared with those with fibrosis (p less than 0.01). This technique offers many advantages over the use of polyclonal antibodies. The 351A is a highly specific ACE inhibitor, chemically defined and in limitless supply. This method enables the quantitation of results, and autoradiographs may be stored indefinitely for later comparison.

Adult↗