Chromosome aberration and lipid peroxidation in chromium-exposed workers

Chromosome aberration frequency and lipid peroxidation levels were analyzed to investigate their efficacy as biological markers for monitoring the genotoxicity and oxidative damage in Korean chromium (Cr)-exposed workers. Fifty-one Cr-exposed workers and 31 age-matched controls in ten chrome-plating plants were sampled. The Cr level was measured in the workers' blood and urine, and in the ambient air at the workplaces. The conventional Giemsa staining method and fluorescence in situ hybridization (FISH) technique were used for chromosome aberration analysis. Spectrum green whole chromosome paint specific for chromosome 4 was used in the FISH procedure. As for lipid peroxidation, malondialdehyde (MDA) was measured in the blood plasma as thiobarbituric acid-reactive substances (TBARS). The blood Cr concentration was statistically correlated with both the frequency of chromatid exchange and the total frequency of chromosome/chromatid breaks and exchanges, as detected by the Giemsa staining. Meanwhile, the frequency of translocation, as detected by the FISH technique, was significantly higher in the Cr-exposed workers than in the controls and it correlated with the blood Cr concentration. Although the concentration of MDA, the metabolite of lipid peroxidation, in the exposed workers was higher than that of the controls, no statistically significant correlation between the MDA level and the blood or urine Cr levels was observed. Accordingly, the genotoxicity and oxidative damage (plasma lipid peroxidation) in the Korean Cr-exposed workers were consequential at quite low exposure levels, plus chromosome rearrangement, especially translocation, was clearly evident as a biological response marker for Cr exposure based on a significant positive correlation between the translocations detected by FISH and the Cr in the blood.

Time course of cerebral infarction in the middle cerebral arterial territory: deep watershed versus territorial subtypes on diffusion-weighted MR images

PURPOSE

To examine possible differences between the evolution of cerebral watershed infarction (WI) and that of territorial thromboembolic infarction (TI) by using diffusion-weighted (DW) and T2-weighted magnetic resonance (MR) images and apparent diffusion coefficient (ADC) maps.

MATERIALS AND METHODS

Fourteen patients with TI and nine with WI underwent MR imaging from the acute to chronic infarction stages. ADC maps were derived from DW images. Lesion-to-normal tissue signal intensity ratios on ADC maps (rADC), echo-planar T2-weighted images, and DW images were calculated. Lesion volumes at acute or early subacute infarction stages were measured on DW images, and final lesion volumes were estimated on fluid-attenuated inversion-recovery images.

RESULTS

Analysis of variance revealed a significant difference in temporal evolution patterns of rADC between WI and TI (P <.001). rADC pseudonormalization following TI began about 10 days after symptom onset, but that following WI did not occur until about 1 month after symptom onset. The Pearson correlation coefficient between final and initial infarct volumes was 0.9899 for both infarction subtypes, indicating that the initial ischemic injury volume measured at the acute or early subacute stage predicted the final lesion volume fairly well.

CONCLUSION

The evolution time of ADC is faster for TI than for WI. This difference, which likely originates from the different pathophysiologic and hemodynamic features of the two infarction types, might account for the relatively large range of ADC values reported for the time course of ischemic strokes.

MR findings of tuberculous dactylitis: case report

A case of tuberculous dactylitis in an immunocompetent patient is presented and the radiographic findings and differential diagnosis discussed. MR image, although nonspecific, was helpful for differential diagnosis and evaluating the extent of the lesion. Although this is a rare condition, the diagnosis should be considered when dealing with an unusual destructive bony lesion.

Expression and Tyrosine Phosphorylation of E-Cadherin, β- and γ-Catenin, and Epidermal Growth Factor Receptor in Cervical Cancer Cells

OBJECTIVES

The cadherin/catenin adhesion complex is fundamentally involved in epithelial cancer invasion and metastasis. Much evidence suggesting that epidermal growth factor (EGF) induced the scattering and invasion of cancer cells, probably by affecting E-cadherin function, has been reported. The present study aimed to confirm the hypothesis that EGF/epidermal growth factor receptor (EGFR) was related with the E-cadherin adhesion system in cervical cancer cells and that EGF might induce tyrosine phosphorylation of beta- and gamma-catenin.

METHODS

Cervical cancer cells were treated for different time durations with 30 ng/ml of EGF. Alteration of the cell morphology was examined by light microscopy and the expression of E-cadherin, beta-catenin, gamma-catenin, EGFR, and activated EGFR was assayed using Western blotting. Tyrosine phosphorylation of beta- and gamma-catenin was also examined using immunoprecipitation.

RESULTS

E-cadherin and EGFR were expressed in CaSki, HT-3, and ME-180 cell lines, which showed epithelial contact growth. The expression of E-cadherin and beta- and gamma-catenin did not change after treatment with EGF. The expression of EGFR decreased and activated EGFR expression increased in 30 min and then decreased subsequently. The simultaneous expression of activated EGFR and tyrosine phosphorylation of beta- and gamma-catenin was found.

CONCLUSIONS

EGF-induced scattering of the E-cadherin-positive cervical cancer cells might be the result of tyrosine phosphorylation of the beta- and gamma-catenin. Phosphorylation of the beta- and gamma-catenin may hamper the adhesive function of the E-cadherin-catenin complex.

[Reverse transcriptase PCR (RT-PCR) and quantitative-competitive PCR (QC-PCR)]

Due to its extraordinarily high sensitivity, polymerase chain reaction (PCR) is widely used for amplifying cDNA copies of low abundance mRNA. However, quantitation is unreliable because the amount of PCR product increases exponentially with each cycle of amplification; therefore, minute differences in any of the variables that affect the efficiency of amplification can dramatically alter product yield. Coamplification with a different reporter gene product is a semiquantitative mRNA quantitation method. Thus, we constructed an internal standard with a defined deletion fragment from the target cDNA, and used the same primers to coamplify the unknown and the competitor, allowing us to quantify the amount of specific target cDNA available. In addition, because the efficiency of amplification of the internal control molecules is identical to that of the target template, quantitative PCR can avoid the discrepancies associated with tube-to-tube or sample-to-sample variations in the kinetics of the RT reaction. For RNA quantitation, Northern blots are widely used. However, the Northern blot technique requires at least 10mg of total RNA for semiquantitation while QC-PCR requires only 1mg of total RNA and is useful when only small amounts of tissue are available. QC-PCR is a simple, and inexpensive method in which competitive PCR is used for highly accurate quantitation of mRNA and DNA from a small number of cells.

Tuberculous versus pyogenic arthritis: MR imaging evaluation

PURPOSE

To assess magnetic resonance (MR) imaging features in differentiating tuberculous arthritis from pyogenic arthritis.

MATERIALS AND METHODS

Findings in 29 patients with tuberculous arthritis were compared with those of 13 patients with pyogenic arthritis. Bone erosion, marrow signal intensity, synovial lesion signal intensity, boundaries (smooth or irregular) for extraarticular extension of infection, and abscess rim enhancement (thin and smooth or thick and irregular) were analyzed.

RESULTS

Bone erosion was more common in patients with tuberculous arthritis (24 [83%] of 29) than in those with pyogenic arthritis (six [46%] of 13) (P =.026), while subchondral marrow signal intensity abnormality was seen more frequently in patients with pyogenic arthritis (12 [92%] of 13) than in those with tuberculous arthritis (17 [59%] of 29) (P =.036). On T2-weighted images, there was no significant difference between the synovial lesion signal intensities of tuberculous arthritis and pyogenic arthritis. Lesions in 16 (70%) of 23 patients with tuberculous arthritis and two (17%) of 12 patients with pyogenic arthritis had smooth extraarticular boundaries, while those in seven (30%) of 23 patients with tuberculous arthritis and 10 (83%) of 12 patients with pyogenic arthritis had irregular boundaries (P =.005). Tuberculous abscesses (16 [100%] of 16) had thin and smooth rim enhancement, while most pyogenic abscesses (five [71%] of seven) had thick and irregular rims (P =.001).

CONCLUSION

MR imaging of bone abnormalities, extraarticular lesions, and associated abscesses provides useful information in the differentiation of tuberculous arthritis and pyogenic arthritis.

Interleukin-1beta regulates urokinase plasminogen activator (u-PA), u-PA receptor, soluble u-PA receptor, and plasminogen activator inhibitor-1 messenger ribonucleic acid expression in cultured human endometrial stromal cells

The interleukin-1 (IL-1) system plays an integral role in local intercellular interactions during implantation. In addition, the plasminogen activator system, especially urokinase plasminogen activator (u-PA), plasminogen activator inhibitor (PAI-1), and u-PA receptor (u-PAR), are crucial during embryo implantation. Decidualization and implantation are complex processes dependent upon several proteases, including u-PA, and IL-1 is known to affect PA activity in several cell types. We investigated the role of IL-1beta in regulating u-PA, PAI-1, u-PAR, and soluble u-PAR messenger ribonucleic acid (mRNA) expression in cultured human endometrial stromal cells using quantitative competitive PCR. For confirmation of the mRNA data, we measured PAI-1 and u-PAR protein by enzyme-linked immunosorbent assay. Confluent stromal cell cultures treated with progesterone and estradiol for 9 days were stimulated with IL-1beta, and IL-1beta plus IL-1beta antibody for an additional 24 h. Total RNA was extracted, reverse transcribed, and coamplified using quantitative and competitive PCR with internal standards. IL-1beta increased PAI-1, u-PAR, and soluble u-PAR expression in a dose-dependent manner, and this result was reversed by anti-IL-1beta antibody treatment. u-PA mRNA expression was not dependent on IL-1beta. These results suggest that IL-1 may be important in regulating PAI-1 and u-PAR during stromal cell decidualization before implantation.

Sonography of acute osteomyelitis in rabbits with pathologic correlation

RATIONALE AND OBJECTIVES

Ultrasonography (US) has a potential role in the diagnosis of osteomyelitis. The purpose of this study was to determine the characteristic sonographic features of acute osteomyelitis and correlate them with pathologic findings.

MATERIALS AND METHODS

An experimental model of acute osteomyelitis was produced in the tibiae of 20 rabbits. Daily US and plain radiography were performed for 2 weeks. The authors evaluated periosteal reaction, subperiosteal fluid collection, and soft-tissue changes seen with US. A hypoechoic band and a hyperechoic line lying along the cortex were considered positive signs of subperiosteal fluid collection and periosteal reaction, respectively. The findings of periosteal reaction were compared for US and radiography, and pathologic findings were also correlated.

RESULTS

The most common sonographic finding was a hypoechoic band along the cortex (21 [75%] of 28 tibiae), usually associated with a linear periosteal reaction (20 [71%] of 28). This juxtacortical abnormal echogenicity corresponded to periosteal elevation with loose fibrovascular connective tissue and granulation, associated with subperiosteal abscess formation. The periosteal reactions were detected with US before they were seen on radiographs. The periosteum showed gradual thickening during the disease process. In 50% of infected tibiae, inflammation or abscess formation was observed in the surrounding soft tissue.

CONCLUSION

US readily demonstrates juxtacortical abnormal echogenicity and soft-tissue infection related to acute osteomyelitis. The abnormal echogenicity correlated well with the pathologic findings of periosteal reaction and subperiosteal abscess.

Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-3 mRNA expression in ectopic and eutopic endometrium in women with endometriosis: a rationale for endometriotic invasiveness

OBJECTIVE

To investigate mRNA expression of metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-3 (TIMP-3) in ectopic endometriosis tissue and uterine endometrium from women with and without endometriosis throughout the menstrual cycle.

DESIGN

Molecular studies in human tissue.

SETTING

Department of Gynecology and Obstetrics, Reproductive Immunology Laboratory, Stanford University Medical Center.

PATIENT(S)

Fifty-three premenopausal woman (23 women with endometriosis and 30 women without endometriosis undergoing laparoscopic surgery). Endometrium and ectopic endometriosis tissue were obtained at the time of surgery.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

mRNA expression from eutopic and ectopic endometrium was analyzed by quantitative, competitive PCR.

RESULT(S)

Both uterine endometrium and ectopic endometriotic tissue from women with endometriosis expressed significantly (P<.05) lower levels of TIMP-3 than endometrium from normal women. Also, ectopic endometrium expressed higher levels of MMP-9 and a higher ratio of MMP-9/TIMP-3 than eutopic endometrium from normal and endometriosis patients.

CONCLUSION(S)

These results suggest that ectopic and eutopic endometrium from endometriosis patients may be more invasive and prone to peritoneal implantation because of greater MMP and less TIMP-3 mRNA expression than endometrium from women without endometriosis. Thus, increased proteolytic activity may be one of the reasons for the invasive properties of the endometrium, resulting in the development of endometriosis.

Malignant melanoma of the sinonasal cavity: explanation of magnetic resonance signal intensities with histopathologic characteristics

PURPOSE

To evaluate the magnetic resonance (MR) findings of malignant melanoma of the sinonasal cavity and compare these findings with those of the histopathological examination.

MATERIALS AND METHODS

The MR images of 11 patients with malignant melanoma of the sinonasal cavity were retrospectively reviewed. Ten patients had primary malignant melanoma of the sinonasal cavity and one had a local recurrence. The imaging findings were evaluated with special attention given to the signal intensity of the tumor, internal characteristics, and growth pattern on MR. Signal intensity and enhancement patterns of the tumors were compared with the histopathological findings.

RESULTS

On T1-weighted image, 6 tumors were hyperintense (5 melanotic and one amelanotic melanoma), and 5 tumors were isointense or hypointense (4 amelanotic and one melanotic). On T2-weighted images, 2 amelanotic tumors showed hyperintensity, and 5 melanotic tumors showed hypointensity. Four tumors (one melanotic and 3 amelanotic) were isointense. Four of the 7 tumors with hyperintensity on T1-weighted images showed patchy, higher-signal intensity areas. In 3 of them, patchy areas of a higher degree of pigmentation were found on histopathological examination. There were multiple linear dark signal intensities on T2-weighted images and/or linear-enhancing areas on enhanced T1-weighted images within the masses in 5 of the 11 patients. These findings could be explained as intratumoral vessels in 4 tumors and fibrous septa in one tumor on histopathological examinations.

CONCLUSION

Malignant melanoma of the sinonasal cavity shows characteristic MR signal intensity, which is mainly attributable to the degree and distribution of melanin pigmentation, and partly attributable to hemorrhage within the mass. The linear, low-signal intensity on T2-weighted images or enhanced lines are intratumoral vessels or fibrous septa.

T2-Weighted fast MR imaging with true FISP versus HASTE: comparative efficacy in the evaluation of normal fetal brain maturation

OBJECTIVE

This study compares the relative efficacy of two fast T2-weighted MR imaging techniques-fast imaging with steady-state free precession (true FISP) and half-Fourier acquisition single-shot turbo spin-echo (HASTE)-in the evaluation of the normal fetal brain maturation during the second and third trimesters of gestation.

SUBJECTS AND METHODS

The brain maturation of 10 normal nonsedated fetuses (5 during the second trimester and 6 during the third trimester of gestation [1 fetus underwent 2 examinations]) was examined by both techniques using a Vision+ 1.5-T MR system. We specifically looked for developing events, including white matter myelination, neuronal migration, and cortical sulcation. Image quality was graded according to the presence or absence of undesirable blurring.

RESULTS

The specific absorption rate was lower for true FISP than for HASTE by a factor of 3 at equivalent imaging conditions. HASTE and true FISP provide comparable image quality in the second trimester when myelination of the cerebrum has not begun. Neuronal migration could be recognized as hypodense bands on both sequences during the second trimester. Myelination beginning at the third trimester was better delineated with true FISP than with HASTE because of point spread function-related blurring effects inherent in HASTE that hampered visualization of short-T2 structures. Cortical sulcation was well delineated by both sequences.

CONCLUSION

With relatively superior image quality and significantly lower radiofrequency absorption than HASTE, true FISP is a safer and more effective alternative in the prenatal evaluation of normal fetal brain.

Heroin-induced spongiform leukoencephalopathy: value of diffusion MR imaging

The diffusion-weighted (DW) magnetic resonance (MR) imaging findings of a patient with subacute stage of heroin-induced vacuolating myelinopathy are reported. The diffuse decrease of apparent diffusion coefficient (ADC) of the white matter on DW imaging is attributed to restricted water diffusion, which is known to be caused by fluid entrapment within the myelin lamellae without demyelination.

Juxtacortical chondromyxoid fibroma arising in an apophysis

We present a rare case of juxtacortical chondromyxoid fibroma arising in the lesser trochanter of the right femur which corresponds to an apophysis. Radiography showed a well-defined expansive lesion with a sclerotic margin measuring 5x3.5 cm in diameter in the lesser trochanter. On spin echo T1-weighted images, the lesion revealed low signal intensity similar to muscle. On spin echo T2-weighted images, the lesion revealed high heterogeneous signal intensity, which after gadolinium injection showed heterogeneous enhancement. The inner margin of the cortex was intact and adjacent bone marrow was of normal signal intensity. The outer margin of the lesion was also clearly defined and extension into adjacent soft tissue beyond the exophytic cortical outgrowth was not evident.

Indirect signs of anterior cruciate ligament injury on SPET: comparison with MRI and arthroscopy

Indirect signs of anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI) include bony contusions in the lateral femoral condyle and the posterior portion of the lateral tibial plateau. This study was undertaken to assess the value of single photon emission tomography (SPET) in the diagnosis of ACL injury by examining the uptake pattern in the distal femur and the proximal tibia. Thirty-five patients were examined using SPET, MRI and arthroscopy. Seventeen patients were found to have ACL tears on arthroscopy. The duration of symptoms was 4 days to 10 years (mean 26.4 months). MRI and SPET images were analysed retrospectively without information from arthroscopic examination. Radionuclide uptake in the lateral femoral condyle and the posterior lateral tibial plateau was considered an indirect sign of ACL injury on SPET. We evaluated the diagnostic value of indirect signs of ACL injury obtained on SPET by comparing these findings with arthroscopic and MRI results. Fifteen of 17 patients with ACL injury showed indirect signs on SPET. The sensitivity, specificity, positive predictive value and negative predictive value for indirect signs of ACL injury were 88%, 56%, 65% and 83% on SPET and 59%, 94%, 91% and 71% on MRI, respectively. However, despite the higher sensitivity of indirect signs on SPET than on MRI, the overall diagnostic value of MRI is better than that of SPET. In the clinical setting, indirect signs of ACL injury may be of value in interpreting incidental findings on SPET.

Analysis of chromosome aberrations in nuclear-power-plant workers considering the lifetime of lymphocytes

PURPOSE

To analyse chromosome aberrations in nuclear-power-plant workers taking account of the mean lifetime of lymphocytes (MLTL).

MATERIALS AND METHODS

Analysis of chromosome aberrations was performed on peripheral lymphocytes from 395 nuclear-power-plant workers and 135 controls. An equivalent acute dose (EAD) was calculated utilizing MLTL values of either 4.3 or 10 years.

RESULTS

Using an MLTL value of 10 years produced an EAD range of 0.O1 mSv -182mSv(mean 46.6mSv), while using an MLTL, of 4.3 years produced results ranging from 0.01 mSv to 86.2 mSv (mean 23.4 mSv). A significant increase of chromosome-type exchange by the equivalent acute dose was observed using an MLTL of either 10 or 4.3 years when including the control in the analysis, but a significant increase was not seen when only the exposed was considered. A significant increase of chromosome-type deletion by EAD was seen even when only the exposed group was considered.

CONCLUSIONS

EAD values based on an MLTL of either 4.3 or 10 years, as well as cumulative dose, showed no significant association with chromosome aberrations, when radiation workers only were analysed. The narrow dose range examined in this study might have contributed to this finding.

Fractal analysis of nuclear medicine images for the diagnosis of pulmonary emphysema: interpretations, implications, and limitations

OBJECTIVE

The purpose of this study was to investigate, on images obtained in nuclear medicine examinations, the physical meanings and consequent implications of fractal analysis developed in a recent study that was reported to be effective in quantifying the heterogeneous distribution of carbon particle radioaerosol in the lungs.

MATERIALS AND METHODS

Fractal dimensions were computed for 108 sets of radionuclide imaging data from 28 patients according to the methods in a previous report, and were then correlated with the ratio of tissue areas segmented at two thresholds (15% and 35% of maximal radioactivity).

RESULTS

Fractal dimension was found to linearly correlate with the ratio natural logarithm of tissue areas segmented at two different threshold levels (n = 108, r = 0.999), with regression slope accurately predicted (error = 0.06%). Bland-Altman analysis showed that fractal dimensions ranging from 0.2 to 1.9 can be explained by this area ratio with disagreement of only 5.13% at two standard deviations; thus, fractal dimension seems to be an over-simplified parameter unrelated to spatial heterogeneity of radioaerosol distribution.

CONCLUSION

The analysis of this study suggested that the fractal dimension defined in a previous report was limited to the indication of the percentage area of low-radioactivity regions with respect to total tissue area in the image. Because the fractal dimension partially reflects, but is not specific to, a certain degree of focal spots of low radioactivity, we suggest using fractal analysis in clinical practice only with careful control and thorough understanding of the physical meanings.

Automatic spike detection via an artificial neural network using raw EEG data: effects of data preparation and implications in the limitations of online recognition

OBJECTIVE

Automatic detection of epileptic EEG spikes via an artificial neural network has been reported to be feasible using raw EEG data as input. This study re-investigated its suitability by further exploring the effects of data preparation on classification performance testing.

METHODS

Six hundred EEG files (300 spikes and 300 non-spikes) taken from 20 patients were included in this study. Raw EEG data were sent to the neural network using the architecture reported to give best performance (30 input-layer and 6 hidden-layer neurons).

RESULTS

Significantly larger weighting of the 10th input-layer neuron was found after training with prepared raw EEG data. The classification process was thus dominated by the peak location. Subsequent analysis showed that online spike detection with an erroneously trained network yielded an area less than 0.5 under the receiver-operating-characteristic curve, and hence performed inferiorly to random assignments. Networks trained and tested using the same unprepared EEG data achieved no better than about 87% true classification rate at equal sensitivity and specificity.

CONCLUSIONS

The high true classification rate reported previously is believed to be an artifact arising from erroneous data preparation and off-line validation. Spike detection using raw EEG data as input is unlikely to be feasible under current computer technology.

The visible man: three-dimensional interactive musculoskeletal anatomic atlas of the lower extremity

A personal computer-based interactive musculoskeletal anatomic atlas of the lower extremity has been created by using the Visible Human Male data set. A semiautomatic segmentation program was developed by using an intelligent scissors approach and shape-based interpolation, thus considerably reducing the laborious work of the segmentation and labeling process. Manual contour extractions at 3-mm section intervals and shape-based interpolations of intervening sections of the musculoskeletal structures of the lower extremity were performed. For interactive and realistic three-dimensional display, an efficient binary volume rendering method was developed that introduces the concept of shear-warp factorization and applies a newly developed normal calculation technique. Binary volume rendering reconstructs various structures from a series of two-dimensional sections in a few seconds, thus enabling real-time manipulations of the computerized atlas. All of the muscles, tendons, and bones of the lower extremity have been segmented and labeled. The volume-based three-dimensional interactive atlas supports various interactions including rotation, removal, highlighting with artificial colors, arbitrary cutting operation, transparent view, and descriptive knowledge representation. In addition, browsing through the two-dimensional images of transverse, coronal, and sagittal views with labeling and segmentation information is possible.

Frame-shift mutation in hormone binding domain of human androgen receptor gene causes complete androgen insensitivity

Mutation of the human androgen receptor gene impairs normal sexual differentiation and development in karyotypic males, resulting in a spectrum of external genital phenotypes ranging from complete female to nearly complete male. The androgen insensitivity syndrome (AIS) is an X-linked disorder in which genetic males fail to undergo normal fetal masculinization or pubertal virilization. PCR amplification of AR exons followed by SSCP analysis was performed with the genomic DNA of a patient having complete AIS. Mutation was observed at the exon E, where a single nucleotide deletion of T at the nucleotide 3286 was observed by cyclic sequencing. A single base deletion in Exon E in the hormone binding domain causes a frame-shift mutation, which leads to changes in the open reading frame, and causes the early termination of AR synthesis. The structural change of the hormone binding domain and AR might cause an insensitivity to the androgen thus leading to AIS.

Genetic integrity of transforming growth factor beta (TGF-beta) receptors in cervical carcinoma cell lines: loss of growth sensitivity but conserved transcriptional response to TGF-beta

Transforming growth factor beta (TGF-beta) exerts an inhibitory effect on the growth of most epithelial cell types, and the loss of responsiveness to this growth inhibition has been implicated in the development of a variety of human cancers. The genetic alteration of TGF-beta receptors is known to play a critical role in this escape from growth regulation. We asked whether there is a correlation between TGF-beta sensitivity and the genetic status of TGF-beta type I and type II receptors (RI and RII, respectively) in human cervical carcinoma cell lines. Among 8 cell lines examined, 3 (ME-180, C-33A and HeLaS3) showed resistance to TGF-beta and 3 (SiHa, CaSki and HeLa229) showed minimal response to the growth inhibitory effect of TGF-beta; the other cell lines (HeLa and HT-3) were sensitive. Northern blot analysis revealed that the RII mRNA was not expressed in 2 TGF-beta-resistant cell lines (ME-180 and C-33A) but was expressed in the other cell lines. Southern blot analysis of RI and RII revealed a homozygous deletion of the entire TGF-beta RII gene in the cell line ME-180. We then asked whether the other TGF-beta-resistant or refractory cell lines had microsatellite instability and/or poly-adenine tract mutations of RII. We also checked for point mutations in the individual exons of the entire RII using polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP). Although C-33A exhibited poly-adenine microsatellite instability, its RII gene showed no signs of mutation. The molecular integrity of the TGF-beta, receptors in all cell lines, except ME-180 and C-33A, could be confirmed by examining the distinct transcriptional induction of plasminogen activator inhibitor-1 (PAI-1), p21(WAF1/CIP1) and, in some cases, the accompanying downregulation of c-myc in response to TGF-beta. Our observations, taken together, indicate that inactivation of the RII contributes to the resistance to TGF-beta of some cervical carcinoma cell lines. Loss of or attenuated sensitivity to TGF-beta growth inhibition in other cells may be attributed to the disruption of distal components in the TGF-beta signal pathway, but not to the receptor system.

A novel ets-related transcription factor, ERT/ESX/ESE-1, regulates expression of the transforming growth factor-beta type II receptor

A 2.5-kilobase cDNA clone that encodes a 371-amino acid novel transcription factor was isolated from a human placenta cDNA library using a yeast one-hybrid system. The novel ets-related transcription factor (ERT) showed a homology with the ETS DNA-binding domain. Using constructs of the transforming growth factor-beta (TGF-beta) type II receptor (RII) promoter linked to the luciferase gene, we have demonstrated that ERT activates transcription of the TGF-beta RII gene through the 5'-TTTCCTGTTTCC-3' response element spanning nucleotides +13 to +24 and multiple additional ETS binding sites between -1816 and -82 of the TGF-beta RII promoter. A specific interaction between ERT and the ETS binding sites was also demonstrated using an electrophoretic mobility shift assay. Deletion mapping of ERT protein suggests that the transactivation domain resides in the amino terminus while the DNA-binding domain is localized to the carboxyl-terminal region. Our results suggest that ERT might be a major transcription factor involved in the transcriptional regulation of the TGF-beta RII gene.