Variation in the expression of human 3 beta-hydroxysteroid dehydrogenase

Polymorphic genetic variation shows that the genes for human 3 beta-hydroxysteroid dehydrogenases (3 beta-HSD) types I and II are closely linked. The type II mutations A82T, S100N and L173R are associated with male pseudohermaphroditism and A82T is associated, with variable penetrance, with female premature puberty. When expressed in vitro A82T showed less than 5% of normal activity and L173R showed a 30-50% reduction in activity. PCR experiments and direct genomic cloning show that there is a larger family of 3 beta-HSD sequences which require to be tested for expression. The phenomenon of epitopic heterogeneity of 3 beta-HSD is discussed and is now shown to apply to testicular Leydig cells as well as extrauterine trophoblast. RT-PCR analyses indicate that the phenomenon is most likely to be due to post-translational modification affecting the carboxytermini 3 beta-HSD types I and II. This phenomenon may reflect a further level at which enzyme activity is regulated.

p53 immunoreactivity in cervical intraepithelial neoplasia and non-neoplastic cervical squamous epithelium

AIMS

To determine the pattern of p53 immunoreactivity in cervical squamous epithelium and to investigate the relation between p53 immunostaining and human papillomavirus (HPV) infection.

METHODS

Immunocytochemistry for p53 was performed in 65 specimens of formalin fixed, paraffin wax embedded cervical tissue using a polyclonal antibody against recombinant p53. Microwave oven heating was used for antigen retrieval. Eight normal biopsy specimens, eight cases with histological features of HPV infection, and 49 cases of cervical intraepithelial neoplasia (CIN) were examined. Thirty one cases of CIN were examined. Thirty one cases of CIN were examined for evidence of HPV infection using in situ hybridisation with probes directed against wide spectrum HPV, HPV 16 and HPV 18.

RESULTS

p53 immunoreactivity was seen in seven of eight (87%) of specimens with histological features of HPV infection, five of eight (62%) normal specimens, 13 of 22 (59%) CIN III, three of 14 (21%) CIN II and five of 13 (38%) CIN I specimens. The numbers of positive nuclei were small in cases of CIN and the location of positive nuclei within the epithelium paralleled the degree of dysplasia. Eleven of 15 (73%) CIN specimens which were immunoreactive for p53 yielded a positive signal for HPV by in situ hybridisation. A positive signal for HPV was also seen in 10 of 16 (63%) of CIN specimens in which p53 staining was absent.

CONCLUSIONS

p53 immunoreactivity can be demonstrated in a small proportion of cells in the cervical squamous epithelium in a significant proportion of cases of CIN. This immunoreactivity seems to be independent of the presence of HPV, as assessed by in situ hybridisation. p53 immunoreactivity also occurs in non-neoplastic cervical squamous epithelium with a pattern of distribution within the epithelium which differs from that seen in CIN. Antigen retrieval by microwave oven heating enhances p53 immunostaining and may result in visualisation of cellular p53 in the absence of mutation.

Localization of EGF receptors in frozen tissue sections by antibody and biotinylated EGF-based techniques

We developed a sensitive EGF receptor detection method for frozen tissue sections using biotinylated EGF as the primary reagent. The method was directly compared with an immunohistochemical technique based on an anti-EGF receptor monoclonal antibody (MAb EGFR1) in normal human and rat tissues and in human tumors. The method was more sensitive than a previously published biotinylated EGF-based technique. In normal human tissues and in 37 of the 50 tumors, the binding pattern mirrored that of positive staining with EGFR1. Five further tumors showed weak immunoreactivity, but in these no binding of biotinylated EGF was detected. The remaining eight tumors were negative by both techniques. The discordant cases may reflect a lower level of sensitivity of the ligand-binding technique or, alternatively, abnormal receptors may have been expressed in these tissues. EGF receptors could be detected in rat liver with biotinylated EGF but not with the antibody, indicating the usefulness of the ligand-based technique in cross-species studies.

A study of general innervation of the human adrenal cortex using PGP 9.5 immunohistochemistry

Immunohistochemical detection of the neurone-specific ubiquitin hydrolase protein gene product 9.5 (PGP 9.5) has been applied to the normal adult human adrenal cortex to define overall patterns of innervation. Three distinct types of nerve morphology were noted in the cortex: large nerve trunks traversing the cortex to the medulla, a complex, branching network of slender nerve bundles and individual nerve fibres. These were more abundant in the head and body than in the alae and tail. Varicosities suggested local neurotransmitter release. Nerve fibres were also identified in the muscular wall of the central vein, which are apparently neither noradrenergic nor cholinergic. These data are in support of a direct role for nerves in the control of adrenocortical function and/or vascular responses in man.

Induction of phenotypic changes in SCLC cell lines in vitro by hexamethylene bisacetamide, sodium butyrate, and cyclic AMP

BACKGROUND

Hexamethylene bisacetamide (HMBA), sodium butyrate (NaBt), and cyclic AMP (cAMP) have been shown to induce differentiation, which may regulate tumour growth differently from conventional cytotoxic drugs. It was the intention in the present study to determine whether alterations could be induced in the phenotype of small cell lung cancer (SCLC) cell lines with HMBA, NaBt and cAMP, and whether these alterations would correlate with reduced growth in vivo, implying a phenotypic shift from malignancy towards differentiation.

MATERIALS AND METHODS

The cell lines were NCI-H69, H187 and H128. The activity of dopa decarboxylase (DDC), the BB isozyme of creatine kinase (CK-BB), the synthesis of bombesin-like peptide (BLI), and the presence of neurone specific enolase (NSE) and chromogranin were used as markers of the small cell phenotype. Clonogenicity in suspension in agar, and growth as xenografts in nude mice, were used as malignancy-associated properties. Cell proliferation in vitro was determined by cell counting and growth curve analysis.

RESULTS

HMBA, NaBt and cAMP were found to be reversibly cytostatic in liquid culture and pre-exposure reduced the cloning efficiency in agar by 60%-80%. Growth as xenografts was inhibited (three- to five-fold increase in the tumour doubling time), most significantly by NaBt. Effects of phenotypic markers were more complex. The most significant were a two-fold reduction in DDC with NaBt and HMBA, a 50% increase in CK-BB with cAMP, and a 70%-100% increase in secreted BLI with HMBA and cAMP, in NCI-H69 cells. No significant effects were seen on NSE and chromogranin. There was little sign of an interaction with adriamycin and vincristine, although a slight increase was observed in the ID50 of VP-16 following treatment with cAMP.

CONCLUSIONS

NaBt, HMBA and cAMP were cytostatic and inhibited tumour growth, but there was no coordinated response in marker expression that would confirm phenotypic alteration indicative of differentiation. The problem of defining differentiation in SCLC further complicated the analysis. The possibility remains of combining these agents with conventional cytotoxics as there appears to be little antagonistic effect, and other studies have suggested synergism may be possible with correct scheduling.

Coincidental occurrence of primary hyperparathyroidism and cancer-associated hypercalcaemia in a middle-aged man

Primary hyperparathyroidism (PHPT) is found not uncommonly in patients with cancer. In this report, however, we describe a patient where both humoral hypercalcaemia of malignancy and PHPT were present coincidentally. A 47-year-old man was found to have PHPT due to parathyroid hyperplasia. Serum parathyroid hormone (PTH) levels, which were elevated before parathyroidectomy, were undetectable post-operatively; however, hypercalcaemia persisted. Nephrogenous cyclic adenosine monophosphate was elevated along with this undetectable PTH, indicative of the presence of a PTH-like factor in the serum. This was confirmed by the finding of an elevated level of PTH-related protein (PTHrP) in plasma (9.1 pmol/l, normal < 2.6 pmol/l). Secondary carcinoma was identified in a lesion in the region of the manubrium sternii. This stained positively for PTHrP by immunocytochemistry and PTHrP messenger RNA was detected by in-situ hybridization. This case illustrates the value of sensitive PTH assays in distinguishing PHPT from other causes of hypercalcaemia and also shows the importance of considering primary hyperparathyroidism in the differential diagnosis of the patient with cancer and hypercalcaemia.

Demonstration of pro-opiomelanocortin mRNA in pituitary adenomas and para-adenomatous gland in Cushing's disease and Nelson's syndrome

Pro-opiomelanocortin (POMC) mRNA was demonstrated in pituitary adenomas from 16 patients with Cushing's disease and 10 with Nelson's syndrome. The intensity of signal was significantly greater in Nelson's syndrome than in Cushing's disease and there was a trend towards a greater proportion of positive cells. This probably reflects inhibition of POMC gene expression by the high circulating levels of cortisol in Cushing's disease. In the para-adenomatous gland, the intensity of signal was variable in cells showing Crooke's hyaline change, ranging from negative to strongly positive, in keeping with the functional heterogeneity of corticotrophs. In one case, junctional corticotrophs were present and these were more intensely stained than anterior lobe corticotrophs in the same gland. This supports the concept that these cells are subject to different regulatory influences from corticotrophs in the anterior lobe. Whether this is related to differences in embryological origins or to local factors is at present unclear.

Expression of the pro-opiomelanocortin gene in lung neuroendocrine tumours: in situ hybridization and immunohistochemical studies

Neuroendocrine tumours of the lung may be associated with the ectopic adrenocorticotrophin (ACTH) syndrome and may synthesize and secrete ACTH-related peptides in the absence of the syndrome. However, immunocytochemical analysis may not confirm these biochemical findings, particularly in small cell carcinoma, which is poorly granulated. To investigate further the morphological evidence for expression of the pro-opiomelanocortin (POMC) gene in neuroendocrine lung tumours, we have examined a series of 46 small cell carcinomas and 13 carcinoid tumours of the lung by in situ hybridization for POMC mRNA using a digoxigenin-labelled oligoprobe. We have compared the findings with the immunocytochemical detection of ACTH and beta-endorphin. In situ hybridization was positive in 15 of 46 small cell carcinomas (33 per cent) and in 8 of 13 carcinoid tumours (62 per cent). Immunocytochemical staining was positive in only one carcinoid tumour. These in situ hybridization studies have corroborated biochemical data indicating POMC gene expression in a high proportion of lung neuroendocrine tumours. This suggests that the low levels of expression detected by immunocytochemistry may be due to low levels of hormone storage. Multivariate analysis showed a weak negative association between POMC expression and survival in small cell carcinomas, although this did not reach statistical significance.

Detection of mRNA by in situ hybridisation and in northern blot analysis using oligodeoxynucleotide probes labelled with alkaline phosphatase

AIMS

To assess whether a reduction in intensity of signal observed using an alkaline phosphatase labelled oligodeoxynucleotide probe could be explained on the basis of procedural steps rather than reduced sensitivity.

METHOD

Signal intensity was assessed on in situ hybridisation for pro-opiomelanocortin (POMC) mRNA in rat pituitary and for somatostatin mRNA in human pancreas and in northern blot analysis for POMC mRNA in the presence and absence of formamide. The direct effects of formamide on the alkaline phosphatase detection step were assessed using histochemical enzyme detection in rat kidney.

RESULTS

All signals were reduced in systems containing formamide.

CONCLUSIONS

In the absence of formamide clear, strong signals for specific mRNAs can be obtained by in situ hybridisation and northern blot analysis using oligodeoxynucleotide probes directly labelled with alkaline phosphatase. Formamide seems to inhibit the activity of alkaline phosphatase.

Expression of epidermal growth factor receptor in normal ovary and in ovarian tumors

Increased expression of epidermal growth factor (EGF) receptor has been recorded in many types of human tumors and has been associated with reduced survival in ovarian carcinoma. The purpose of this study was to examine the immunocytochemical distribution of the EGF receptor in normal ovaries (n = 30) and in ovarian tumors (n = 126). Staining was observed in two normal ovaries, in the granulosa cells of a developing follicle, and in surface epithelium. Forty-seven of 103 malignant common epithelial tumors were immunopositive. Staining was usually focal, always confined to the neoplastic epithelium, and showed a cytoplasmic distribution. There was a slight trend for increased EGF receptor expression in more advanced common epithelial malignancies, but this was not statistically significant. No correlation between immunoreactivity and histological subtype or grade of tumor was seen. A few other tumors were also examined: one each of Brenner tumor, mature teratoma, mature teratoma with squamous carcinoma, borderline serous tumor and fibroma; all were immunopositive.

A comparison of biochemical and immunohistochemical assessment of EGFR expression in ovarian cancer

The presence of epidermal growth factor receptor (EGFR) was determined both by immunohistochemistry and ligand binding assay in 118 samples from 96 cases of ovarian cancer. EGFR was present in 47.5% of tumours biochemically and in 39.8% of tumours analysed immunohistochemically. The concordance rate for the techniques varied between 40% in endometrioid carcinomas to 85.7% in undifferentiated carcinomas with an overall concordance of 69.5% (p < 0.001). There was no significant difference between the presence of the high, low or high plus low affinity receptor components and tumour immunoreactivity. Although the ligand binding assay is more sensitive than immunohistochemistry for detecting the epidermal growth factor receptor, some cases are positive only on immunohistochemical screening. We would recommend that both techniques should be performed in prospective studies in order to elucidate the role of EGFR expression in ovarian cancer.

In situ Hybridization demonstrates the stability of mRNA in post-mortem rat tissues

In situ hybridization was used to detect messenger RNA (mRNA) in a variety of rat tissues which were fixed in formalin either immediately after death or after a 24 h period of storage at 5 degrees C. A synthetic polydeoxythymidine [poly d(T)] oligonucleotide probe was used to demonstrate polyadenylated [poly (A)] mRNA in the small intestine, pancreas, liver, cerebellum, and pituitary. Of these tissues, only the liver showed a small reproducible reduction in hybridization signal following delayed fixation. Synthetic oligonucleotide probes complementary to albumin and pro-opiomelanocortin (POMC) mRNAs were hybridized to liver and pituitary, respectively. There was no significant reduction in hybridization signal in post-mortem tissues. The results suggest that some mRNAs may be remarkably stable under certain post-mortem conditions and this should encourage the wider application of in situ hybridization techniques to post-mortem material.

Primary cutaneous plasmacytoma: the use of in situ hybridization to detect monoclonal immunoglobulin light-chain mRNA

A case of primary cutaneous plasmacytoma in a 16-year-old male is described. The neoplastic nature of the plasma cell infiltrate has been clearly established by the demonstration of monoclonal kappa immunoglobulin light-chain mRNA using in situ hybridization with biotin-labelled oligonucleotide probes applied to routine tissue sections.

Distribution of type IV collagen immunoreactivity to assess questionable early stromal invasion

AIMS

To determine if the immunocytochemical delineation of subepithelial basement membrane can be used in the assessment of questionable early invasive cervical carcinoma.

METHODS

The distribution of immunoreactive type IV collagen was examined in 15 cervical biopsy specimens in which the reporting pathologist had specifically described difficulty in assessing or excluding early invasion of subepithelial stroma associated with cervical intraepithelial neoplasia (CIN). The results were compared with those from biopsy specimens showing CIN III (N = 8), carcinoma with definite early stromal infiltration (FIGO stage 1a1) (n = 6), and more advanced invasive squamous tumours (FIGO stages 1a2 to 3) (n = 8). In all cases the immunocytochemical findings were assessed in relation to serial sections stained with haematoxylin and eosin.

RESULTS

Six of the 15 diagnostically problematic biopsy specimens were considered, on review, to show early infiltration of subepithelial tissue and putative invasive foci were consistently absent in basement membrane. A similar pattern was observed in the "definite" early invasive cases. Eight problematic biopsy specimens were considered to show only in situ neoplasia; five of these had intact though occasionally attenuated basement membrane, three showed focal type IV collagen defects. In the remaining case biopsy trauma precluded further assessment. Basement membrane defects were identified in five of eight cases of CIN III, while three of eight squamous carcinomas showed partial retention of type IV collagen immunoreactivity around invasive tumour cell nests.

CONCLUSIONS

Defects in subepithelial basement membrane occur in in situ and invasive neoplasia in the uterine cervix. Immunocytochemical staining for type IV collagen is of limited diagnostic value in the assessment of biopsy specimens with questionable early stromal invasion.

Pituitary macroadenomas associated with hyperprolactinaemia: immunocytochemical and in-situ hybridization studies

OBJECTIVE

We have assessed whether in-situ hybridization for prolactin messenger RNA (mRNA) provides additional information for the classification of pituitary macroadenomas associated with hyperprolactinaemia.

DESIGN

In-situ hybridization for PRL mRNA was performed on surgical biopsies of pituitary adenomas and the results correlated with serum PRL levels and PRL immunoreactivity.

PATIENTS

Twenty-one patients (11 men, 10 women) were included; five had normal serum PRL levels, 11 mild hyperprolactinaemia (less than 3000 mU/l) and five marked hyperprolactinaemia (greater than 3000 mU/l).

MEASUREMENTS

Immunocytochemistry for PRL and in-situ hybridization for PRL mRNA were performed on surgical biopsies.

RESULTS

Immunoreactivity for PRL was detected in tumours from all patients with serum PRL greater than 3000 mU/l and in one of 11 patients with mild hyperprolactinaemia. Positive signal for PRL mRNA was detected in four of five immunopositive cases studied, in a further two cases with mild hyperprolactinaemia, and in one tumour associated with normal serum PRL level.

CONCLUSIONS

In-situ hybridization provides evidence of PRL gene activation in the absence of immunoreactivity for prolactin. This may reflect low levels of hormone storage or defective translation of the mRNA.

Identification and characterisation in vitro of cells with a non-SCLC cell-like phenotype derived from a continuous SCLC cell line

Two adherent sublines, H69V and H69VZ, have been isolated from the classic SCLC cell line NCI-H69. Significant morphological differences were observed between the parental and the derivative cell lines. While NCI-H69 grew as densely packed free floating cellular aggregates the derivative lines grew as a monolayer of epithelioid cells. The growth rates of both the derivative lines were faster than the parental line with doubling times closer to non-SCLC cell lines in the derivative lines. Both H69V and H69VZ either express very low levels or do not express neuroendocrine cell markers including L-dopa-decarboxylase (DDC), creatine kinase-BB isoenzyme (CK-BB), bombesin-like immunoreactivity (BLI), neuron specific enolase (NSE), and neurosecretory type dense core granules (DGCs), compared to the parental cell line. All the lines stained positive for epithelial markers such as CAM5.2. LDH isoenzyme and chromosome analyses confirmed the human origin of all the cell lines. Therefore, it appears that cell line NCI-H69 contains stem cell subpopulation capable of generating cells of both small and non-small cell like phenotypes.

Non-isotopic in situ hybridization with digoxigenin and alkaline phosphatase labelled oligodeoxynucleotide probes. Applications in pituitary gland

We report the application of digoxigenin labelled oligonucleotide probes for the detection of hormonal messenger RNAs (mRNAs) in human pituitary adenomas. Positive signal for the appropriate mRNA was detected in tumours associated with Cushing's disease, acromegaly and hyperprolactinaemia, where immunoreactivity for adrenocorticotrophin (ACTH) growth hormone and prolactin had also been confirmed. In addition, we report the detection of proopiomelanocortin (POMC) mRNA in the rat pituitary gland using an oligodeoxynucleotide probe directly linked to alkaline phosphatase.

Oncogene transfection of mink lung cells: effect on growth characteristics in vitro and in vivo

Three sublines have been derived from the parental line Mv1Lu by transfection with normal and mutated Ha-ras, and myc oncogenes, and subsequent cloning. All the oncogenes have increased the growth rate of the cell in vitro, increased their plating efficiency in monolayer and suspension, and reduced their serum dependence. Growth in vivo as xenografts in nude mice has also been increased. Very few tumours were generated from the parental line and those that did form did so after a prolonged lag period, while the transfected lines produced tumours with 100% efficiency, and a short lag period. In general the effects of ras transfection were more extreme, with the highest growth rates and plating efficiencies in vitro and the shortest lag period and doubling times in vivo. There was no increase in plasminogen activator activity as a result of transfection, and the invasive behaviour of the lines in organotypic culture was broadly similar.

Detection of mRNA for ribosomal phosphoprotein P2 in normal colon and colonic tumours by in situ hybridization

We have localized the mRNA for the ribosomal phosphoprotein P2, a putative metastasis-related sequence, in normal colon and colonic carcinomas by in situ hybridization, using an oligonucleotide probe end-labelled with digoxigenin. The mRNA was identified in normal colonic epithelial cells, the intensity of the signal being greater in cells at the base of the crypts compared with those on the surface. A strong positive signal was also seen in plasma cells, in fibroblasts in granulation tissue, in ganglion cells, and in hepatocytes. A positive signal was identified in all 16 primary colonic tumours studied and in 7 hepatic metastases. In contrast to previous studies based on Northern blot analysis, we were unable to demonstrate increased expression in metastases as compared with primary tumours, nor could we demonstrate any increased expression in primary tumours which were associated with distant metastases.

Vasopressin stimulation of cell proliferation in the rat pituitary gland in vitro

Proliferative activity was measured in rat anterior pituitary cells in short-term culture by calculating the labelling index (LI), based on the immunohistochemical detection of cells incorporating the thymidine analogue bromodeoxyuridine. Basal LI was reproducible in the test system. Arginine vasopressin (AVP) induced a dose-related increase in LI up to 20 ng/ml. Corticotrophin-releasing factor-41 (CRF-41) had no effect at doses up to 20 ng/ml. However, in the presence of 10 ng CRF-41/ml, AVP induced a greater increase in LI at lower doses than did AVP alone. Fibroblast growth factor also induced a significant increase in LI. In the system used, epidermal growth factor and insulin had no effect on proliferation.

Detection of messenger RNA using a digoxigenin end labelled oligodeoxynucleotide probe

A synthetic oligodeoxynucleotide sequence complementary to the mRNA for the adrenocorticotrophin (ACTH) precursor pro-opiomelanocortin (POMC) was end labelled using digoxigenin. The probe was used to detect POMC mRNA both on nitrocellulose filters and by non-isotopic in situ hybridisation (NISH) in tissue sections. Digoxigenin was identified using anti-digoxigenin alkaline phosphatase. The model system examined was the rat pituitary gland. Removal of both adrenal glands and dexamethasone administration were used to change the concentrations of POMC mRNA in the rat anterior lobe. The labelled probe reacted with a single band of appropriate molecular weight in Northern blot analysis. The distribution of signal in tissue sections and the changes induced by experimental manipulation were as predicted. The results indicate that this method of NISH will prove useful in the detection of specific messenger RNAs in tissue sections of buffered, formalin fixed, paraffin wax embedded material.

Immunoreactive alpha interferon in cervical flat koilocytic lesions and intraepithelial neoplasia

Immunocytochemical staining for alpha-interferon was carried out on cervical biopsy specimens showing non-condylomatous koilocytic atypia (n = 12) and cervical intraepithelial neoplasia (n = 18), both of which are associated with human papilloma virus (HPV) infection. Normal cervical tissue obtained from hysterectomy specimens was also assessed. Koilocytes were not immunoreactive for alpha interferon and keratinocyte staining was observed in only four cases of intraepithelial neoplasia. HPV infection alone does not therefore seem to induce the production of alpha interferon in cervical squamous epithelium. There was variable but, in some cases, prominent staining of cells in the stromal inflammatory infiltrate as well as intraepithelial cells which had morphological and immunocytochemical characteristics of Langerhans' cells. Alpha interferon immunoreactivity in Langerhans' cells is in keeping with derivation from the mononuclear phagocyte system and may be important in the host response to HPV infection.

Association between CAM 5.2 and anti-CD1a reactivity in lymph nodes and gastrointestinal tract epithelium

Immunocytochemical studies, using the antibodies CAM 5.2 and NA1/34 (CD1a), were performed on normal lymphoid tissue and malignant lymphomas. A population of dendritic cells in the paracortex of lymph nodes and in T cell lymphomas reacted with both antibodies. Colocalisation with antibodies was also found in gastrointestinal epithelium. Immune blotting shows that the likely basis of this reactivity is a 12 kilodalton peptide which is recognised by both antibodies. This is almost certainly the beta t peptide which has been described as the light chain of CD1a.

Age-related variation in circadian rhythms of mitosis in the adrenal cortex of the male rat

Using a metaphase arrest technique, mitotic activity was quantified in the adrenal cortex over a 24-h period in 14-day-old male Sprague-Dawley rats before functional rhythmicity of the hypothalamic pituitary-adrenal (HPA) axis is established, and after its onset, in 6- to 7-week-old rats. At all times, proliferative activity was greater in the younger animals, as previously reported. A significant circadian rhythm was identified in both groups, but the timing of the peak differed, lying between 17.00 and 21.00 h at 14 days and 11.00 and 15.00 h at 6-7 weeks. These results raise the possibility that functional rhythmicity of the HPA axis may alter an inherent proliferative rhythm.