市川 智彦

The recently identified prostate cancer susceptibility gene ELAC2 ( HPC2) harbors two common missense variants, a serine to leucine substitution at residue 217 (Leu217) and an alanine to threonine substitution at residue 541 (Thr541). We genotyped the two variants in a Japanese cohort consisting of 350 prostate cancer patients 242 male population controls, and 114 male low-risk controls. Both missense alleles, Leu217 and Thr541, were carried at higher frequency in Japanese patients than in the controls (Leu217, P= 0.0012; Thr541, P = 0.0145), and the odds ratios associated with carrying these sequence variants were higher in Japanese than in Caucasians. Although the Leu217 and Thr541 variants of ELAC2 are less common in Japanese than in Caucasians, both variants confer significantly increased risk of prostate cancer in Japanese. Carriage of these variants was not associated with age at diagnosis, tumor stage, or tumor grade in these Japanese prostate cancer patients. The allele-specific pattern of risk observed in Japanese and familial Caucasian patients was qualitatively similar; however, the magnitude of that risk was considerably greater in Japanese than in Caucasians.

We reviewed 10 cases of laparoscopic adrenalectomy for pheochromocytoma and compared the results with those of a recent series of 11 patients who underwent open adrenalectomy. Of the 10 cases, the tumor was removed successfully in all cases except in one case with laparoscopy that required open laparotomy. A pair of laparoscopic coagulating scissors was utilized in all except the initial two cases. In the laparoscopy group (excluding the initial two cases and the case that required conversion to open surgery), mean operative time and blood loss were 145 min and 55 ml, respectively. No significant difference was observed in mean operative time between the laparoscopy group and the open surgery group (165 min for open surgery). Mean blood loss of the laparoscopy group was significantly less than that of the open surgery group (330 ml for open surgery, P = 0.01). Mean intervals to first ambulation and oral intake, and postoperative hospital stay of the laparoscopy group, tended to be less than those,of the open surgery group, although no statistical significance was observed (2.3 versus 3.2 d, 2.9 versus 3.6 d, and 12 versus 14 d, respectively). We conclude that laparoscopic adrenalectomy for pheochromocytoma is equally effective and less invasive than open adrenalectomy and should be considered the therapy of choice even for pheochromocytoma. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

Expression of the KAI1 gene, a metastasis-suppressor for prostate cancer, is reduced in all foci of prostatic metastasis. The altered regulatory mechanism is not strongly related to mutations or allelic losses of the KAI1 gene in prostate tumors. Since transcriptional silencing of genes has been found to be caused by epigenetic mechanisms, we have investigated the involvement of this epigenetic regulation of KAI1 expression in prostate cancers. The methylation status of the KAI1 promoter region was examined by restriction-enzyme digestion and sequencing, after amplifying a 331-bp fragment in the GC-rich promoter region from 4 human prostate cancer cell lines treated with bisulfite. The same 4 cell lines were also exposed to various concentrations of the demethylating agent, 5-aza-2′-deoxycytidine (5-AzaC) and/or the histone deacetylase inhibitor, trichostatin A (TSA). To clarify the influence of epigenetic modification on reduced KAI1 mRNA expression in the tumor cells, RT-PCR and northern-blot analyses were performed. Bisulfite-sequencing data showed a few methylated CpG islands in the promoter. RT-PCR analysis of 5-AzaC and/or TSA-treated cells indicated reversal of suppression of KAI1 transcription in two cell lines (PC-3 and DU-145), although the expression could not be detected by northern blots. From these results, it is suggested that epigenetic change is not the main mechanism of KAI1 down-regulation, though there remains a possibility that methylation in a more upstream region might be associated with this regulation.

Background: To clarify the implications and limitations of external beam radiation monotherapy for localized prostate cancer, the long-term outcomes and prognostic factors were investigated. Methods: Between 1976 and 1994, 91 patients with untreated prostate cancer were treated with external beam radiation therapy alone. Thirty-two were classified as T1b, eight were T2a, four were T2b and 47 were T3. Pelvic lymphadenectomy was carried out in 69 cases; 57 were staged as pN0, eight were pN1, four were pN2 and 22 were pNX. Linac X-rays were used in 55 cases, fast neutron in 15 and a combination of the two in 21. No other therapy was given until relapse and when relapse was evident endocrine therapy was started. Results: The observation period ranged from 3 to 206 months with a median of 78 months. Local control rate and disease-free, cause-specific and overall survivals at 10 years were 74.0, 49.6, 74.2 and 39.2%, respectively. By univariate analysis, T category, pN category and histologic grade were significant prognostic indicators for disease-free survival. Multivariate analysis revealed that T category was an independent prognostic factor. In T2b and T3 diseases, pN0/1 patients demonstrated significantly better disease-free survival than pNX. Conclusions: A favorable long-term outcome was achieved by external beam radiation monotherapy in patients with minimally extended prostate cancer (T1b and T2a). For locally advanced disease (T2b and T3), staging pelvic lymphadenectomy would be useful for the selection of patients.

Background: The clinical course of patients with T4 prostate carcinoma was examined in order to consider whether there are alternative treatment options besides androgen ablation therapy. Methods: From 1986 to 1995 at Chiba University Hospital, there were 22 cases of T4 prostate carcinoma. Sixteen cases had no bone metastasis at initial diagnosis. Tumor grade and response of prostate-specific antigen (PSA) to endocrine treatment were evaluated in these 16 cases. Results: Four patients had moderately differentiated and 12 had poorly differentiated adenocarcinoma. For initial treatment, all patients received endocrine therapy. Anti-androgen therapy was effective in 15 cases and the 5 year cause-specific and progression-free survival rates were 72.1 and 38.1%, respectively. Patients with moderately differentiated tumors tended to have a longer disease-free period than those with poorly differentiated tumors (P=0.047). Conclusions: Endocrine therapy was effective in patients with T4 tumors. It was suggested that aggressive local treatment (i.e. radiotherapy) in combination with endocrine therapy may be considered if the patients had no distant metastases and had a long life expectancy.

Purpose: The aim of the present study was to investigate the effect of radiotherapy on the local progression of hormone-refractory prostate cancer. Methods: From 1986 to 1995, 38 patients were diagnosed with local progression without distant progression after hormonal therapy at Chiba University Hospital. Eleven cases were treated with irradiation for local progression. External beam irradiation was delivered to the prostate at a dose of 50-66.6 Gy. Results: In patients treated with radiotherapy, the duration from initial treatment to local recurrence was 6-80 months (mean +/- SD: 33.9 +/- 22.9 months). The follow-up period after irradiation was 7-64 months (mean +/- SD: 25.4 +/- 18.8 months). Three and 5 year cause-specific survival rates from radiotherapy were 46.2 and 23.1%, respectively. Radiotherapy had a marked effect on symptoms associated with local progression and no patients suffered from the symptoms after the radiotherapy. Complications of radiotherapy were limited. Conclusions: In patients with hormone refractory local progression without distant progression, low morbidity, low mortality radiotherapy offers a variable therapy to other palliative treatments because radiotherapy is able to control local symptoms for a long period of time.

Cyclophosphamide (CPM) has been considered to be a factor of bladder carcinogen. A 60-years old woman had been received a total dose of 370 g of CPM for the treatment of Wegener's granulomatosis since August, 1977. She was consulted to our department with chief complaint of macrohematuria in August, 1986. Hemorrhage cystitis was diagnosed and cystoscopy and urine cytology were performed as follow-up schedule in every year. In 1996, urine cytology showed class IV and cystoscopy revealed multiple nonpapillary tumors. Abdominal computerized tomography demonstrated a low density mass on the posterior wall of the bladder. A transurethral cold cup biopsy showed G3 transitional cell carcinoma (TCC). Radical cystectomy and tubeless cutaneous ureterostomy was performed on December 6, 1996 and histopathological diagnosis was TCC, G3, pT3 bNXM 0. She died of liver failure due to metastatic bladder cancer after seven months postoperatively.

BACKGROUND. In previous reports, we used microcell fusion-mediated chromosomal transfer to introduce normal human chromosomes into highly metastatic rat prostatic cancer cells to map the location of tumor and metastasis suppressor genes. The gene for prostate-specific antigen as well as several classes of genes, including cell adhesion molecules, previously demonstrated to be altered during prostate cancer progression, were mapped to human chromosome 19. METHODS. A normal human chromosome 19 was introduced into Dunning-R3327 AT6.1 rat and TSU-prl human prostatic cancer cells by microcell-mediated chromosome transfer to test the suppressive effects of this chromosome on prostate cancer. Five independent hybrid clones from Dunning-R3327 AT6.1 rat prostatic cancer cells and four independent hybrid clones from TSU-prl human prostatic cancer cells were isolated, karyotyped, allelotyped, and analyzed for in in vitro and in vivo growth characteristics. RESULTS. Introduction of human chromosome 19 into both the rat and human prostatic cancer cells resulted in alteration of cell morphology in vitro and suppression of tumorigenicity in vivo in athymic nude mice. Highly polymorphic SSR2 markers mapped to human chromosome 19 were used to determine the portions of human chromosome 19 retained in the hybrids. These analyses identified a region localized on human chromosome 19p13.1-13.2 that is responsible fur the tumor suppression of both rat and human prostatic cancer cells. The expression of several genes previously mapped to this human chromosome 19p13.1-13.2 region (i.e., ICAM-1, Notch3, and Stau) were analyzed to evaluate if they could be candidate suppresser genes for prostate cancer cell growth in vivo, but no expression patterns consistent with those predicted for a suppressor gene were observed. CONCLUSIONS. Human chromosome 19p13.1-13.2 contains potential tumor suppressor gene(s) for prostate cancer. (C) 1999 Wiley-Liss, Inc.

患者は46歳女性. 近医で高血糖の精査中, 腹部超音波検査で両側の副腎に直径約8cmの腫瘤を指摘され当科紹介. 家族歴は姉と姪が von Hippel-Lindau 病 (VHL). CT, MRIにて両腎の嚢胞, 小脳の血管芽腫を認めた. 血圧200/100mmHg, 空腹時血糖138mg/dlで, 血中, 尿中のノルアドレナリンが優位に上昇し, ¹³¹I-MIBGシンチで両側の副腎に著明な集積がみられた. VHLに合併した両側の褐色細胞腫と診断し, 1996年9月25日経腹的両側副腎摘除術を行った. 右は, 75×60×120mm, 450g, 左は45×70×110mm, 330gであった. 病理診断も褐色細胞腫であり, 術後血圧, 血糖値, ノルアドレナリンともに正常化し, 術後約15ヵ月の現在経過良好である.<br>VHLに合格した両側褐色細胞腫は, 自験例が本邦7例目である. 家族歴に褐色細胞腫のある患者はVHLの合併も考慮して, 中枢神経系, 網膜や腎臓, 膵の検索も必要であると思われた.

To evaluate the relationship between prostate-specific antigen (PSA) levels and prostate volume and age in a mass screening for prostatic disease, a total of 1,162 examinees from one Japanese prefecture who were over 45 years of age underwent a mass screening for prostatic disease that used the Hybritech (Tandem(R)RIA) kit, and the prostate volume was estimated by transabdominal ultrasonography. Differences among several groups of men according to prostate volume and age were examined by multiple comparisons using ranks. When some subjects visited several times, the data of the first visit were adopted only. The total number of individual subjects in this study was 589 men. The multiple comparisons using ranks and 10-year age brackets revealed that the levels of PSA showed significant differences between only two pairs of groups stratified by age. In contrast, the levels of PSA showed significant differences among seven pairs of groups stratified by the prostate volume according to 10-ml brackets. When a logarithmic transformation of the serum levels of PSA was used, the results showed the same tendencies. From the results of the present study, it can be said that the PSA reference range calculated with stratified prostate volume might be more useful in the detection of prostate cancer than that calculated with stratified age.

Background: This study was designed to evaluate the distribution of prostate-specific antigen (PSA) levels of men in a mass screening program for prostatic disease. Methods: A total of 763 men over 40 years of age underwent mass screening for prostatic disease in a Japanese prefecture using the highly sensitive Eiken kit and the Hybritech (Tandem-R) kit. The screening tests consisted of serum PSA determination, digital rectal examination, a questionnaire on symptoms, evaluation of prostate volume, and determination of the obesity rate. Results: Serum PSA levels of all subjects were measured with both kits. The correlation between the values obtained by the Eiken kit and those of the Tandem-R kit was high (r = 0.990), but the values of the former were slightly higher than those of the latter. Serum PSA weakly correlated with age, however, when estimated within decade age brackets, the levels of PSA showed significant differences among only 1 pair of groups stratified by age. In contrast, the levels of PSA showed significant differences among 9 pairs of groups stratified by prostate volume. Conclusion: A highly sensitive assay kit is useful to evaluate both the distribution of PSA levels and the relationship of PSA values to age and prostate volume of men in mass screening programs for prostatic disease, since approximately 40% of the subjects who underwent the present mass screening showed PSA values under 1.0ng/mL, which have been the the lower limit of detection of many PSA kits.

Prostate cancer is one of the most commonly diagnosed cancers and is a major cause of cancer death in men. Although the majority of the diagnosed prostate cancers will remain localized and never produce clinical symptoms during the lifetime of the host, a subset of these cancers will progress to a more malignant state requiring therapeutic intervention. Acquisition of metastatic ability by prostatic cancer cells is the most lethal aspect of prostatic cancer progression. Once this has occurred, definitive therapy is required before the initially localized metastatic cells escape from the prostate. At present, metastatic prostate cancer is incurable. Therefore, there is an urgent need to develop molecular markers that can be used to predict the metastatic potential of prostate cancers. Using somatic cell hybridization, we have demonstrated that acquisition of metastatic ability requires both the loss of metastasis-suppressor funct ion(s) and the activation of oncogenes. In further studies using microcell-mediated chromosomal transfer, we located genes on human chromosome, 8, 10cen-q23, 11p11.2-13, and 17pter-q23, which, when introduced into rat prostatic cancer cells, are capable of suppressing their metastatic ability without affecting their tumorigenicity or growth rate in vivo. Initially we focused upon the human chromosome 11p11.2-13 region to clone metastasis-suppressor gene(s) positionally. One such gene, termed KAI-1, encodes a membrane glycoprotein. KAI-1 has been mapped to the p11.2 region of human chromosome II by fluorescence in-situ hybridization analysis. Expression of KAI-1 has been detected in all normal human tissues thus far tested, including prostate tissue. When introduced into rat metastatic prostatic cancer cells, KAI-1 significantly suppressed the metastasis without affecting the tumor growth rate, KAI-1 expression is high in human normal prostate and benign prostatic hyperplasia but is dramatically lower in cancer cell lines derived from metastatic prostate tumors.

Background: Although several studies indicate that larger varicoceles are associated with greater impairment of spermatogenesis, others suggest that the response to surgery is independent of varicocele size. In order to elucidate these seeming contradictions, correlations between the preoperative evaluation of varicoceles and improvement in semen quality after varicocelectomy were investigated, Methods: Forty men with left unilateral varicocele, followed for at least 6 months after varicocelectomy, were included in this study. The relationships between the grade of varicocele by palpation, Doppler examination, ultrasound, or scintigraphy were correlated with a postoperative improvement in sperm density or sperm motility. Results: Greater improvement in sperm density was observed in the patients with a large varicocele graded by palpation or measured by ultrasound, and greater improvement in sperm motility was observed in the patients with high uptake of radioactivity in the left side by scrotal scintigraphy. Conclusion: An improvement in semen quality after varicocelectomy is greater in patients with a large varicocele than in the patients with a small one. The significance of surgical repair of a small varicocele should be reconsidered.

Background: The effects of castration on the biological features of an androgen-responsive carcinoma were examined in order to clarify the mechanism responsible for the relapse of an androgen-responsive carcinoma after androgen ablation therapy. Methods: A well-characterized androgen-responsive mammary carcinoma, Shionogi carcinoma 115 (SC115), was used for these experiments. Male mice were examined for the effects of castration on the growth rate of the tumor, the number of androgen receptor-positive cells, and the karyotype of the SC115 tumors. Castration was performed 1 week prior to tumor transplantation, or 2 or 3 weeks after tumor transplantation. Results: SC115 tumors did not develop when transplanted into castrated male mice. When castration was performed 2 weeks after transplantation, the tumor showed androgen-independent growth with temporary regression of growth rate. However, when castration was performed more than 3 weeks after transplantation, the tumor showed androgen-independent growth not associated with any temporal regression of growth rate. There were no significant differences in histological features or the number of androgen receptor-positive cells between SC115 tumors in untreated or castrated mice. To test whether SC115 tumors growing under androgen-deprived conditions became fully androgen-independent, SC115 tumors were transplanted in both male and female mice. A transplanted tumor piece grew progressively only in male mice. This indicates that the SC115 tumor maintains its androgen response in the next generation, even though growth of the tumor resumed after temporary suppression due to castration. Chromosomal analyses revealed no apparent, cytogenetic changes in the SC115 tumors that resumed growth under androgen-deprived conditions. Conclusion: These results suggest that no gross changes in the number of androgen receptor-positive cells or karyotype are necessary for androgen-independent growth in this system once the size of tumor increased.

To examine the role of human chromosome 10 in development of prostatic cancer, we introduced human chromosome 10 into highly metastatic rat prostatic cancer cells by microcell-mediated chromosome transfer. Microcell hybrid cells introduced with human chromosome 10 showed suppression of the metastatic ability to the lung to some extent without any suppression of tumorigenicity, although the tumor growth rate decreased slightly. To minimize the region that contains metastasis suppressive activity, the hybrid cells in metastasis foci of lung were established in culture and reanalyzed for portions of human chromosome 10 retained in the metastasis tissues. Cytogenetic and molecular analyses demonstrated that loss of the region between 10cen and D10S215 on human chromosome arm 10q was related to expression of the metastatic phenotype. These results demonstrate that the region between 10cen and D10S215 on human chromosome arm 10q contains at least one of the metastasis suppressor genes for rat prostatic cancer. (C) 1995 Wiley-Liss, Inc.

Metastasis suppressor activities have previously been mapped to human chromosomes 17 and 11. Decreased expression of the metastasis suppressor gene NM23, which is located on chromosome 17, has been correlated with increased metastatic potential in mammary cancers. A region on human chromosome 11, from 11p11.2p13, has been shown to suppress metastasis in rat prostatic carcinoma cells. in both cases the metastasis suppressor activity had no effect on tumorigenicity or tumor growth rate, demonstrating that the encoded activities are distinct from effects of tumor suppression. To determine whether these human chromosomes encode general or tissue-specific metastasis suppressor activities, a truncated human chromosome 17 (ie., pter-q23) and a full-length human chromosome 11 were separately transferred into highly metastatic rat mammary and prostate cancer cell lines and tested for their ability to suppress spontaneous metastasis in vivo. These studies demonstrated that when the pter-q23 region of human chromosome 17 is retained by the microcell hybrids, the metastatic ability of both mammary and prostatic cancer cells is suppressed. In contrast, when the pter-q14 region of human chromosome 11 is retained, only the metastatic ability of prostatic cancer cells is suppressed. Additional studies demonstrated that the metastasis suppressor activity encoded by the chromosome 17 pter-q23 region is p53-independent and not due to enhanced expression of NM23 protein.

Most androgen-unresponsive prostatic cancer cells are found to lack androgen receptor (AR). To clarify the role of AR in the process of the progression from androgen-dependent to androgen-unresponsive tumor, the AR gene was transfected into an AR-negative rat prostatic cancer cell line CUB-II. AR-transfectant cells expressed AR mRNA and showed binding to R1881. AR was found in nuclei of AR-transfectant cells by histochemical examination. Therefore, AR-transfectant cells were considered to contain functional AR. The growth of AR-transfectant cells was markedly inhibited in culture in the presence of testosterone, and the effect of testosterone was reduced by simultaneous addition of flutamide. Moreover, tumors inoculated with AR-transfectant cells in male mice showed much slower growth than those in females. The tumors of AR-transfectant cells in mice consisted of slightly larger spindle-shaped cells when compared to those of CUB-II cells. Moreover, AR-transfectant cells contained a few polynuclear giant cells. Since CUB-II cells contained acid phosphatase (AcP) activity, the addition of testosterone in culture increased AcP activity of AR-transfectant cells. It is concluded that resumption of androgen-dependent processes reduces the growth rate accompanying changes of phenotype. (C) 1994 Wiley-Liss, Inc.

To examine the natural course of human benign prostatic hyperplasia (BPH), cases in health care examination with or without slight urinary symptoms were examined by echography. In comparison with these cases, the size of the prostate was examined in patients who received prostatectomy. Prostatic sizes of health care cases varied widely along with increasing age,but could be divided into two groups: increasing or no-change. According to serial determinations of prostatic sizes in the increasing group, the annual growth rate of the prostate was calculated as 1.65 +/- 1.13 and 0.85 +/- 0.44 g in men &lt;65 years old and in men greater than or equal to 65 years old, respectively. Distribution of prostatic sizes as a function of age in heal:h care cases was similar to that in operated patients, showing that the size was not correlated with urinary symptoms or surgical indication. Since uroflow rates decreased along with increasing age in the no-change group of operated patients, aging was a factor in deterioration of uroflow. Between the increasing and the no-change groups in health care cases, differences were found in total cholesterol and neutral fat in serum, in addition to gamma-seminoprotein; the latter may be due to differences in the size of the prostate. In conclusion, natural course of the prostatic hyperplasia is separated into two groups, increasing and no-change. Occurrence of urinary symptoms does not simply relate to an increase in prostatic weight but, at least in part, to the aging process. (C) 1994 Wiley-Liss, Inc.

The urodynamic status of a 24 year old male patient with psychogenic erection who sustained a conus medullaris lesion from a burst fracture of the first lumbar vertebra is reported. During the initial measurement the external urinary sphincter pressure began to rise from the base pressure of 35 cm H2O 5 seconds after the beginning of audiovisual sexual stimulation and reached the peak of 110 cm H2O. In parallel, tjie bladder neck pressure gradually rose from its base pressure of 5 cm H2O to a maximal pressure of 115 cm H2O and then ejaculation occurred. The difference is no more than 5 cm H2O and this small difference in pressure inhibits retrograde ejaculation. © 1994 International Medical Society of Paraplegia.

An inhibitory effect of TZP-4238, a newly synthesized antiandrogen, on the growth of Dunning R3327 rat prostatic tumor was studied and compared with that of chlormadinone acetate (CMA). TZP-4238 markedly suppressed the growth of R3327 tumor. The inhibitory effect of TZP-4238 on the tumor was more potent than that on the prostate. While the inhibitory effect of TZP-4238 on the weight of the ventral prostate was about 6 times as great as that of CMA, the suppressive effect of TZP-4238 on tumor weight was about 40 times as great as that of CMA. Serum levels of testosterone and dihydrotestosterone showed no obvious changes after the administration of either TZP-4238 or CMA. The inhibitory effect of TZP-4238 on the growth of R3327 tumor indicated the application of the compound to human prostatic cancer.

Androgen receptor is necessary for the proliferation of androgen-dependent tumors including human prostatic cancer and murine androgen-sensitive tumors. However, androgen-independent tumor containing functional androgen receptor was observed in CS 2 cells, which is a subline of androgen-dependent mouse tumor (SC 115). CS 2 showed a new expression of hst-1, the product of which is a family of FGF. CS 2 secreted a growth factor which promotes growth of CS 2 and original SC 115 in an autocrine and paracrine manner. The role of oncogene (s) and suppressor gene (s) on the progression of the tumor is discussed.

Following v-Ha-ras transfection of nonmetastatic dimethylbenz[a]anthracene-induced rat mammary cancer (RMC1) cells, occasional transfectants were isolated that acquired high metastatic ability. High metastatic ability is not a simple process regulated by v-Ha-ras p21 levels alone in these v-Ha-ras transfectants but involves the development of cytogenetic changes. If such cytogenetic changes involve only gain in gene expression, then all hybrids formed by fusing highly metastatic v-Ha-ras RMC1 transfectants with the parental nonmetastatic RMC1 should be highly metastatic. If loss of a metastatic suppressor gene(s) is also involved, then such hybrids should be nonmetastatic since chromosomes from the nonmetastatic parental cells should supply the suppressor function. To test this possibility, a highly metastatic cloned v-Ha-ras transfectant was fused with the nonmetastatic parental RMC1 cells. Five hybrid clones were isolated that conserved the chromosomes from their parental cells. When these hybrid clones were injected into animals, primary tumors developed with the same tumor-doubling time as that of the highly metastatic parental v-Ha-ras transfectant (i.e., almost-equal-to 2 days). High metastatic ability was, however, suppressed in these hybrid clones. All hybrid clones continued to express v-Ha-ras p21. Thus, suppression of metastatic ability in the hybrids can occur even in the presence of an elevated v-Ha-ras p21 level. This suggests that the acquisition of metastatic ability following v-Ha-ras transfection involves loss of metastasis suppressor gene function in rat mammary cancer cells.

Progression of prostatic cancer from nonmetastatic to high metastatic ability may involve the loss of 2 metastasis suppressor gene. To test this possibility, nonmetastatic and highly metastatic Dunning rat prostatic cancer cells were fused. Hybrid clones were isolated which conserved the chromosomes from their parental cells. When these hybrids were injected into animals, none developed distant metastases. When these nonmetastatic primary tumors were passaged in vivo, occasional animals developed distant metastases. Cytogenetic analysis of eight of these metastatic revertants demonstrated a consistent loss of a copy of a normal chromosome. 2. Although previous studies have demonstrated that specific chromosomes can inhibit tumorigenicity in cell fusion experiments, this is the first study to show that prostatic cancer metastasis is associated with the loss of a specific chromosome. Furthermore, these studies suggest that a metastasis suppressor gene for rat prostatic cancer is located on chromosome 2.

To study the relationship between metastatic ability, mutated H-ras expression, and genetic instability, a cloned, nonmetastatic rat prostatic cancer cell line (AT2.1) was transfected with the v-H-ras oncogene. The parental AT2.1 clone, 4 control transfectants (Neo/Only), and 9 v-H-ras transfectants (Neo/Ras) were characterized with regard to their H-ras content by using Southern, Northern, and Western blot analysis and their biological behaviour in vivo. Following s.c. inoculation in syngeneic rats, all transfectants produced tumors. All 4 (Neo/Only) transfectants like the parental untransfected cell were non-metastatic. Six of 9 Neo/Ras transfectants were metastatic to the lungs and lymph nodes, while the other 3 Neo/Ras transfectants were not metastatic. There was no simple dose-response relationship between the level of v-H-ras integration, mRNA or p21 protein expression, and the development of metastatic ability by the Neo/Ras transfectants. Cytogenetic analysis demonstrated that the frequency of additional structural and/or additional numerical chromosomal changes among the Neo/Ras transfectants was significantly higher than that in the Neo/Only transfectants (P &lt; 0.05). Loss of chromosome 10 was observed in all of the Neo/Ras transfectants, whereas that was observed in only one of the 4 Neo/Only transfectants (P &lt; 0.05). There were no specific chromosomal changes, however, which were statistically correlated with the development of metastases in the Neo/Ras transfectants. These results demonstrate that development of the metastatic ability in AT2.1 cells is not a single-step reaction regulated by the level of H-ras expression alone, but rather a complex process requiring additional events. One of the additional events appears to be an increase in genetic instability and cytogenetic changes following v-H-ras transfection.

We isolated and sequenced the rearranged genomic variable (V) and joining (J) gene segments of T cell receptor ɑ -chain gene from two independent keyhole limpet hemocyanin (KLH)-specific suppressor T cell (Ts) hybridomas (BW5147 x C57BL/6 KLH-Ts). These nucleotide sequences were compared with those of germline DNA from kidney and also with cDNA of ɑ-chaln (VJɑ1281) previously isolated from Ts hybridoma (34S-281) with KLH/H-2b Ts activity. The entire Vɑ and Jɑ sequences of all three Ts, hybridomas were exactly identical and were encoded by the germline Vɑ and Jɑ gene segments without any mutations, except for 2-nucleotide deletions from both the 3‧ end of Vɑ and the 5‧ end of Jɑ gene segments, respectively, and a 1-nucleotide (guanine) Insertion in the junctional (N) region which was not encoded by the germline gene. Six additional KLH-Ts hybridomas, further analyzed, also possessed the same ɑ-chain, indicating the preferential usage of the particular ɑ-chain In these hybridomas. As chromosome analysis demonstrated a different pattern In each clone, these hybridomas appear to be independent. More surprisingly, 0.5 -1.5% of the total functional T cell ɑ-chain mRNA in the thymus and spleen of unprlmed C57BL/6 mice was found to be of this particular ɑ-chaln. These results suggest that the repertoire of KLH-Ts is strictly limited. © 1989 The Japanese Society for Immunology.