Additive antitumour effect of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (Iressa, ZD1839) and the antioestrogen fulvestrant (Faslodex, ICI 182,780) in breast cancer cells.

A high expression level of epidermal growth factor receptor (EGFR)/HER1 has been suggested to lead to a shorter survival time and resistance to endocrine therapy in patients with breast cancer. To test the hypothesis that inhibition of the EGFR signalling pathway affects the antitumour effect of endocrine therapy, an EGFR tyrosine kinase inhibitor (EGFR-TKI), gefitinib, and an oestrogen receptor (ER) antagonist, fulvestrant, were administered to human breast cancer cells. A total of five human breast cancer cell lines were used. The effects of single or combined treatments with gefitinib and/or fulvestrant on cell growth, cell cycle progression and apoptosis were analysed. Changes in the expression levels of cyclin-dependent kinase inhibitors, p21 and p27, an antiapoptotic factor, Bcl-2, and a proapoptotic factor, Bax, were also investigated. All cell lines tested were sensitive to gefitinib (50% growth inhibitory concentration, 10-28.5 microM). Breast cancer cell lines with a high expression level of HER1 or HER2 were more sensitive to gefitinib than the others. Gefitinib induced a significant G1-S blockade in ER-positive KPL-3C cells. Gefitinib induced significant apoptosis in HER1-overexpressing MDA-MB-231 cells. Gefitinib additively increased the antitumour effect of fulvestrant in all three ER-positive cell lines in a medium supplemented with 17beta-oestradiol. The combined treatment promoted cell cycle retardation in KPL-3C cells, which is associated with an upregulation of p21 by fulvestrant and gefitinib, respectively. Apoptosis was associated with downregulation of Bcl-2 by gefitinib in MDA-MB-231 cells. These results suggest an additive interaction between the EGFR-TKI gefitinib and the antioestrogen fulvestrant in ER-positive breast cancer cells.

A radicicol derivative, KF58333, inhibits expression of hypoxia-inducible factor-1alpha and vascular endothelial growth factor, angiogenesis and growth of human breast cancer xenografts.

A novel oxime derivative of radicicol, KF58333, binds to the heat shock protein 90 (Hsp90) and destabilizes its associated signaling molecules. These effects play a critical role in the growth inhibition of tumor cells. To further investigate the effects of this agent, it was administered to two human breast cancer cell lines, KPL-1 and KPL-4, both in vitro and in vivo. KF58333 dose-dependently inhibited the growth and vascular endothelial growth factor (VEGF) secretion, concomitantly with a decrease in VEGF mRNA expression, in each cell line. This agent also suppressed the increase of VEGF secretion and expression induced by hypoxia (1% O(2)). Intravenous injections of this agent into nude mice bearing either KPL-1 or KPL-4 xenografts significantly inhibited the tumor growth associated with a decrease in the Ki67 labeling index and microvascular area and an increase in apoptosis and the necrotic area. These findings indicate that the antitumor activity of this radicicol derivative may be partly mediated by decreasing VEGF secretion from tumor cells and inhibiting tumor angiogenesis. To explore the action mechanisms of the anti-angiogenic effect, the expression level of hypoxia-inducible factor (HIF)-1alpha was investigated. KF58333 provided a significant decrease in the HIF-1alpha protein expression under both normoxic and hypoxic conditions. In contrast, the mRNA expression of HIF-1alpha was not decreased by this agent. It is suggested that the post-transcriptional down-regulation of HIF-1alpha expression by this agent may result in a decrease of VEGF expression and tumor angiogenesis.

Combined effects of docetaxel and fluoropyrimidines on tumor growth and expression of interleukin-6 and thymidine phosphorylase in breast cancer xenografts.

PURPOSE: Although several combination treatments with docetaxel and other antitumor agents have been tested in experimental and clinical studies, their synergistic effects are still ill-defined. The degree of synergism between docetaxel and two oral fluoropyrimidines, tegafur and 5'-deoxy-5-fluorouridine (5'-dFUrd), was investigated in the KPL-4 human breast cancer xenograft model. METHODS: Because this KPL-4 cell line secretes interleukin-6 (IL-6) and induces cachexia, the effects of the combined treatment on serum IL-6 levels and cachectic markers were investigated. In addition, the expression levels of thymidine phosphorylase (dThdPase), a key enzyme for converting 5'-dFUrd to 5-fluorouracil, were determined. Female nude mice bearing KPL-4 tumors were treated orally with 5'-dFUrd (60 mg/kg, five times a week) or tegafur (100 mg/ kg, five times a week) and by intraperitoneal injection of docetaxel (5 or 10 mg/kg, once a week). RESULTS: Although docetaxel (5 mg/kg) alone did not decrease either tumor growth or serum IL-6 levels, docetaxel (5 mg/kg) plus 5'-dFUrd or tegafur enhanced tumor growth inhibition and decreased serum IL-6 levels more than 5'-dFUrd or tegafur alone. Docetaxel (5 mg/kg) alone slightly increased the percentage of dThdPase-positive tumor cells, but the combined treatment with docetaxel plus 5'-dFUrd or tegafur significantly decreased the percentage of dThdPase-positive cells in the KPL-4 tumors. CONCLUSION: These findings indicate that docetaxel may stimulate dThdPase expression in tumor tissues and may enhance the antitumor activity of oral fluoropyrimidines. In addition, combined treatment with docetaxel and oral fluoropyrimidines may decrease serum IL-6 levels and may ameliorate IL-6-induced cancer cachexia.

Hypoxia reduces hormone responsiveness of human breast cancer cells.

Resistance to hormonal therapy frequently occurs following successful treatment in breast cancer. The mechanism responsible for this acquired resistance is still unknown. It has been suggested that a hypoxic tumor microenvironment promotes malignant progression of cancer, i.e., hypoxia may promote estrogen-independent growth (a more malignant phenotype) of breast cancer. To clarify this hypothesis, the effects of hypoxia on the growth responses to hormonal agents and the expression levels of estrogen receptor (ER)-alpha and progesterone receptor (PgR) were investigated in two human breast cancer cell lines, ML-20 and KPL-1. The expression level of ER-alpha was significantly decreased by hypoxia (1% O(2)) in a time-dependent manner in both cell lines. Hypoxia also significantly reduced the growth-promoting effect of estradiol (E2) and the growth-inhibitory effects of an antiestrogen, ICI 182 780, and a progestin, medroxyprogesterone acetate, in both cell lines. In addition, hypoxia markedly suppressed the induction of PgR mRNA and protein by E2 in both cell lines. To clarify further the effect of hypoxia on ER-alpha expression, the expression levels of hypoxia-inducible factor-1 alpha (HIF-1 alpha), a marker of hypoxia and ER-alpha were immunohistochemically examined in 36 breast cancer specimens. ER-alpha expression (both its proportion and intensity) was significantly lower in nuclear HIF-1 alpha-positive tumors than in negative tumors. These findings indicate that hypoxia down-regulates ER-alpha expression as well as ER-alpha function in breast cancer cells. These processes may lead to an acquired resistance to hormonal therapy in breast cancer.

[Endocrine therapy for advanced or recurrent breast cancer].

Endocrine therapy of advanced or recurrent breast cancer was described. The presence of ER or PgR in primary breast tumors is the best-established marker for response to endocrine therapy. However, ER-positive breast tumors overexpressing EGF-R and/or HER-2 (Erb B2) are resistant to endocrine therapy. Recently it was suggested that an elevated level of the circulating extracellular domain of HER-2 could be a predictor for poor response to endocrine therapy. LH-RH agonist is used as a first-line therapy for premenopausal patients. And LH-RH agonist plus tamoxifen (TAM) has shown a higher response rate and more prolonged survival than LH-RH agonist or TAM alone. As two new aromatase inhibitors, anastrozole (ANA) and letrozole, have shown an equal or higher response rate and a prolonged time to progression than TAM as a first-line therapy, these could be used as a first-line therapy instead of TAM. In a cross-over trial of ANA and TAM, the response rate of ANA after TAM failure was equal to that of TAM after ANA failure. As these drugs showed an equal or higher response rate and longer survival than progestin in TAM resistant cases, these drugs could also used as a second-line therapy. In addition, the trend of recent studies regarding the mechanisms of hormone resistance is also described.

Intranodal benign thyroid tissue: significance of HBME-1 in differentiation from metastatic papillary thyroid carcinoma.

The aim of this study was to determine the significance of HBME-1 immunostaining in the differentiation between intranodal benign thyroid tissue and metastatic papillary thyroid carcinoma in the lymph node. Immunohistochemically we examined normal-appearing intranodal thyroid tissue in four patients who did not show evidence of papillary carcinoma histologically or clinically. We also examined follicular-pattern-predominant papillary carcinoma with metastatic foci in the lymph nodes. Normal-appearing intranodal thyroid tissue and normal thyroid showed no immunopositivity for HBME-1. In contrast, all papillary carcinomas in both the lymph nodes and thyroid demonstrated strong positivity for HBME-1. HBME-1 was predominantly positive for the luminal surface of the tumor cells. The immunopositivity of the cuboidal and low columnar carcinoma cells was more intensive than that of the flat-shaped cells in the lymph nodes and thyroid. The results probably indicate that HBME-1 immunostaining is helpful in distinguishing between intranodal benign thyroid tissue and metastatic papillary carcinoma in lymph nodes. We emphasize that the HBME-1 reactivity should be evaluated in connection with the histological findings, and that positive and negative controls stained in parallel are necessary.

Predictive factors for response to endocrine therapy in patients with recurrent breast cancer.

Predictive markers and variables for response to anticancer therapy provide cancer patients with refinement of therapeutic options and a decreased likelihood of receiving an ineffective therapy. The best-established predictive marker for response to endocrine therapy for breast cancer is the status of estrogen receptors (ER) in the primary breast tumor. However, although patients with ER-positive tumors have a greater than 50% objective response rate to endocrine therapy, other patients can not obtain an objective response. Therefore additional markers, such as better molecular biologic markers, are needed. Our previous study using multivariate analysis revealed that the ER status of primary tumors and the dominant site of metastasis are independent predictors for response to first-line endocrine therapy and that a response to first-line endocrine therapy is only an independent predictor for response to second-line endocrine therapy. However, all these factors are already well-established predictive markers for response to endocrine therapy. Recently, a number of new hormonal agents, such as more selective aromatase inhibitors and specific antiestrogens, have been developed and introduced. However, several questions, such as the best sequences when using hormonal agents, remain to be elucidated. On the other hand, several molecular biologic markers predicting response to endocrine therapy, such as the expression of the HER family of tyrosine kinase receptors, pS2, Bcl-2, and vascular endothelial growth factor, have been reported. To elucidate the most effective use of endocrine therapy for recurrent breast cancer, classical and new predictive factors for response to endocrine therapy are reviewed, and the clinical implications of these factors are discussed.

Changes of expression level of the differentiation markers in papillary thyroid carcinoma under thyrotropin suppression therapy in vivo immunohistochemical detection of thyroglobulin, thyroid peroxidase, and thyrotropin receptor.

BACKGROUND AND OBJECTIVES: Differences in the expression levels of Thyroglobulin (Tg), Thyroid peroxidase (TPO) and thyrotropin receptor (TSH-R) in primary and recurrent specimens under a suppressive serum TSH condition were elucidated in 26 papillary carcinoma patients. METHODS: Immunohistochemical detection was performed by use of each monoclonal antibody against Tg, TPO, and TSH-R. The staining concentrations of the three markers in each specimen were measured for comparison. RESULTS: The mean staining concentrations of Tg, TPO, and TSH-R in the entire primary tumor were 103.92, 104.6 and 89.25, respectively. Five cases showed stronger expression of all the differentiation markers and eight cases showed weaker expression of all these markers in recurrent tissue than in primary tumors. The weaker expression of TSH-R at the recurrent site as compared with that at the primary site significantly demonstrated the shortness of the disease free interval or overall survival. There were significant differences between the death due to cancer and the weaker expression of TSH-R in the recurrent tumor as compared with that in the primary tumor. CONCLUSIONS: Under the TSH suppressive condition, the markers were not expressed uniformly among recurrent tumors. Even under that state, however, low expression of TSH-R in the recurrent tissue was strongly related to a poorer outcome in the patients.

Endocrine therapies for patients with recurrent breast cancer: predictive factors for responses to first- and second-line endocrine therapies.

Breast cancer patients have been treated with four different hormonal agents, antiestrogen, progestin, luteinizing hormone-releasing hormone agonist and aromatase inhibitor, during the past 7 years in Japan. To investigate the efficacy of these agents for the treatment of recurrent breast cancer patients, we conducted a retrospective multi-institute survey in Japan. The clinico-pathological data of 131 patients, who received endocrine therapy as first-line treatment between 1993 and 1998, were collected from seven institutes. The median age of the patients was 55 (range 27-92) years, 75% of their primary tumors were estrogen receptor (ER)-positive or unknown, and 95% of the dominant metastatic sites were bone, soft tissue or lungs. The objective response rate to first-line endocrine therapy was 42.7%, and that to second-line therapy 42.5% (17 of 40 patients). Multiple regression analyses of predictive factors for a response to first- and second-line endocrine therapies indicated two independent factors, ER status of the primary tumors and dominant site of metastasis, for the former, and one independent factor, a response to first-line endocrine therapy, for the latter. Analysis of relationships between sequences of use of hormonal agents and objective response rates revealed that the choice of first-line hormonal agent did not influence the overall efficacy of first- and second-line endocrine therapies. Overall survival after first recurrence in patients with tumors exhibiting an objective response or stable disease to first-line endocrine therapy was significantly better than that in patients with tumors exhibiting progressive disease (p < 0.01). These findings suggest that an adequate selection of recurrent breast cancer patients referring the ER status, dominant site of metastasis and a prior response to endocrine therapy may contribute to better clinical outcomes of the patients.

Interstitial brachytherapy for recurrent breast cancer using a high dose rate Ir-192 remote afterloading system: a report of two cases.

We employed interstitial brachytherapy using a high dose rate Ir-192 remote afterloading unit in two breast cancer patients with locoregional recurrence. In the first case, skin metastasis was treated, with favorable control of the infield tumor but subsequent persistent sequelae and multiple outfield metastases. This experience caused us to be cautious when choosing brachytherapy for the second case, in whom a solitary metastasis to an axillary lymph node was successfully treated. Although this method is still investigational, it may play a critical role in the treatment of locoregional recurrence resistant to other treatment modalities.

Paradoxical hormone responses of KPL-1 breast cancer cells in vivo: a significant role of angiogenesis in tumor growth.

In our previous study, the growth of KPL-1 human breast cancer cells was found to be stimulated by an antiestrogen, ICI 182, 780, and inhibited by 17 beta-estradiol (E2) in vivo but not in vitro. To investigate the action mechanisms of these paradoxical responses, the effects of E2, ovariectomy (Ovex) and medroxyprogesterone acetate (MPA) on the growth, angiogenesis, apoptosis and expression of vascular endothelial growth factor (VEGF) were investigated. E2 stimulated the growth of KPL-1 cells but MPA inhibited it in vitro. In contrast, E2 propionate inhibited the growth of KPL-1 cells in female nude mice but Ovex and MPA stimulated it. E2 propionate suppressed angiogenesis and increased apoptosis in KPL-1 tumors, but Ovex and MPA promoted angiogenesis and decreased apoptosis. Both mRNA expression and secretion of VEGF were stimulated by MPA in KPL-1 cells, but in E2-dependent ML-20 cells they were both inhibited by MPA. E2 did not significantly influence VEGF expression in either cell line. These findings suggest that the abnormal modulation of VEGF expression by MPA and of the other angiogenic factor by E2 are responsible for the paradoxical growth responses of KPL-1 cells in vivo. To support this hypothesis, an antiangiogenic agent, TNP-470, was administered to mice bearing KPL-1 tumors. TNP-470 significantly inhibited the growth of KPL-1 tumors stimulated by MPA. Antiangiogenic agents may be effective for the treatment of hormone-refractory breast cancer.

All-trans-retinoic acid modulates expression levels of thyroglobulin and cytokines in a new human poorly differentiated papillary thyroid carcinoma cell line, KTC-1.

A new human thyroid carcinoma cell line, KTC-1, was established from the malignant pleural effusion of a recurrent thyroid carcinoma patient. Cytogenetic analysis revealed a normal karyotype, and no p53 mutation in exons 5-9 was detected. This cell line is tumorigenic in athymic nude mice. Histological findings by light and electron microscopy, such as the absence of follicular structures and the existence of intranuclear cytoplasmic inclusions and psammoma bodies, indicated transplanted tumors to be a poorly differentiated papillary thyroid carcinoma. A low expression level of thyroglobulin was detected by immunocytochemistry and RT-PCR. Messenger ribonucleic acid (mRNA) expression of thyroid transcription factor-1 and PAX-8 was also detected. No mRNA expression of TSH receptors, thyroid peroxidase, or Na+/I- symporter was detected. Interleukin-6 and leukemia inhibitory factor were secreted into the medium. These findings suggest this cell line to be functionally poorly differentiated. Moreover, all-trans-retinoic acid increased the mRNA expression of thyroglobulin and decreased both the mRNA expression and secretion of interleukin-6 and leukemia inhibitory factor while significantly stimulating growth. RT-PCR analysis of retinoic acid receptors (RARs) revealed that KTC-1 cells express a moderate level of RARalpha and -gamma, but a low level of RARbeta. This cell line may be useful for studying redifferentiation therapy for thyroid carcinoma.

[A case of advanced breast cancer associated with humoral hypercalcemia that responded to medroxyprogesterone acetate and docetaxel].

A 67-year-old woman with a left advanced breast cancer was admitted to our hospital. Chest CT revealed a parasternal lymph nodal metastasis invading into the sternum, an axillary lymph nodal metastasis, and a lung metastasis. The clinical stage of the patient was i.v. (T4bN2M1). Laboratory examination showed humoral hypercalcemia. After controlling the hypercalcemia with alendronate, sodium hydrate she received chemoendocrine therapy with medroxyprogesterone acetate (MPA) (800 mg/day) and docetaxel (60 mg/body once every three weeks). A complete response was obtained in the primary and metastatic lesions after 3 cycles of docetaxel. This case suggests the efficacy of the combined therapy with MPA and docetaxel on advanced breast cancers.

[Comparison of whole-body MR imaging and bone scintigraphy in the detection of bone metastases from breast cancer].

The aim of this study was to investigate the usefulness of whole body MR imaging (WB-MRI) in the detection of bone metastases from breast cancer and to compare the results with those from bone scintigraphy. In 21 patients with suspected bone metastasis from breast cancer, both bone scintigraphy and WB-MRI were performed. With WB-MRI, coronal images were obtained using a body coil in an FOV of 48 cm, and sequences of fast short TI inversion recovery (STIR) and gadolinium-enhanced fast spoiled GRASS (SPGR) were used in three parts: from the head to the thorax, the abdomen to the pelvis, and the lower extremities. Of the total 105 metastatic bone lesions, 65 (61.9%) were detected by bone scintigraphy, 98 (93.3%) by fast STIR, and 74 (70.5%) by fast SPGR. Thus, the detection of bone metastases by WB-MRI was excellent. However, detectability in the ribs was lower for WB-MRI than for bone scintigraphy. Contrast-enhanced MRI was useful in the differentiation of osteosclerotic lesions, in which high signal intensity is rare, pleural effusion, which has high signal intensity on STIR, and bone metastatic lesions. In conclusion, WB-MRI showed high reliability in the detection of bone metastatic lesions from breast cancer.

Semi-quantitative comparison of the differentiation markers and sodium iodide symporter messenger ribonucleic acids in papillary thyroid carcinomas using RT-PCR.

OBJECTIVE: To investigate the levels of expression of the sodium iodide symporter (NIS) and three differentiation markers (thyroglobulin (Tg), thyroid peroxidase (TPO) and thyrotrophin receptor (TSH-R)) in 35 patients with primary (n=31) or recurrent (n=4) papillary thyroid carcinoma, and to compare the findings with clinical data. METHODS: We performed a multiplex semi-quantitative RT-PCR to analyse the relative levels of expression of Tg, TPO and TSH-R mRNAs, and a separate semi-quantitative RT-PCR for NIS mRNA. RESULTS: Tg, TPO and TSH-R mRNAs were expressed in all the patients, whereas NIS mRNA was expressed in all but eight. Analysis of the expression of the differentiation markers in all patients showed a significant correlation among Tg, TPO and NIS. With regard to the relationship between the expression of each gene and the MACIS score, there was significant correlation only for the Tg gene (P<0.05). CONCLUSIONS: The levels of expression of NIS mRNA correlated significantly with those of Tg and TPO mRNAs, but not with those of TSH-R mRNA. The relationship with clinical stage and prognostic score, however, varied among these differentiation markers.