Synergistic inhibitory effect of high-intensity focused ultrasound combined with chemotherapy on Dunning adenocarcinoma

OBJECTIVE: To evaluate the therapeutic effect of high-intensity focused ultrasound (HIFU) combined with chemotherapy (paclitaxel + estramustine) on AT2 Dunning adenocarcinoma, as no satisfactory treatment for localized prostate cancer is available for patients with a poor prognosis, e.g. stage T3, a high Gleason score, or a prostate-specific antigen level of >15 ng/mL. MATERIALS AND METHODS: Forty-one Dunning AT2 tumour-bearing Copenhagen rats were divided into four groups, i.e. control, chemotherapy, HIFU, and chemotherapy + HIFU (the last three treated for 1 week). The growth in tumour volume was recorded for 3 weeks, the point at which tumour volume was considered to have doubled (doubling time). The growth curves of each group were plotted and evaluated statistically. RESULTS: At 30 days of follow-up the distributions of tumour volume with treatment group were significantly different (P < 0.001); volumes were significantly greater in the control than in the chemotherapy-only or in the HIFU-only group (both P = 0.006). The greatest difference was between the chemotherapy + HIFU and the control group. The tumour doubling times were 13.2 days for HIFU-only, 31.2 days for chemotherapy + HIFU and 7.7 days for the controls. CONCLUSION: These results suggest that this combined therapy could be useful for treating patients with high-risk prostate cancer.     

Effect of diethylstilbestrol and estramustine phosphate (estracyt®) on delayed hypersensitivity response to oxazolone in male mice

The effects of diethylstilbestrol (DES) and estramustine phosphate (EMP) on delayed hypersensitivity response (DTH) to oxazolone in male mice were investigated using a radioisotopic ear method. DES significantly inhibited the ability to express a DTH response and was most effective when given during the effector phase of the reaction. EMP had no effects when the animals were exposed to the drug during the effector phase, while it resulted in a strong and dose-dependent depression of the DTH response when applied in the sensitization phase. Possible involvement of suppressor cells was investigated by pretreatment of animals with cyclophosphamide or by adoptive transfer of tentative suppressor cells from spleen, lymph nodes, or peritoneal cavity. However, no evidence of cellular or humoral suppressor factors induced by drug treatment was found.     

The impact of docetaxel, estramustine, and low dose hydrocortisone on the?quality of life of men with hormone refractory prostate cancer and their?partners: A feasibility study

Objectives:The quality of life (QoL) of 44 men with HRPC and 37 partners (primary caregivers, most residing with the patient) was assessed in a multicenter Phase II trial of docetaxel, estramustine and low dose hydrocortisone (CALGB 9780). A secondary objective was to test the feasibility of assessing partners QoL in a cooperative group setting. Patients and methods:Patients and partners were separately interviewed by telephone at baseline, two, four and six months by a single trained research interviewer. Patients QoL was measured by the FACT-P, Mental Health Inventory-17 (MHI-17), Brief Pain Inventory (BPI), a two-day log of pain medications, and the OARS for co-morbid conditions. Partners QoL was measured by the MHI-17, Caregiver Burden Interview, and co-morbid conditions. Results:The QoL study refusal rates were low for patients (4%) and partners (3%). Although patients tended to experience greater treatment side effects in the first two months (FACT Physical Well-Being item, P = 0.057), their cancer-specific emotions (e.g., worrying about worsening health) significantly improved at two and four months (FACT-Emotional Well-Being, P = 0.003, P = 0.03, respectively), as did their prostate cancer-specific physical problems (e.g., urination, pain), at two and four months (FACT-P, P = 0.001, P = 0.005, respectively). Partners anxiety significantly decreased over time (MHI,P < 0.05). Patients quality of life at two months was significantly related to their clinical response (FACT-P total and prostate cancer-specific problems, P < 0.05), and their clinical response was significantly related to a decrease in their partners anxiety at two months (MHI, P < 0.05). Conclusions:Despite feeling worse from side effects, patients prostate cancer-specific problems and emotional state significantly improved in the first four months of treatment. With treatment significantly affecting both patients and partners lives, and the successful assessment of partners QoL, QoL of both patients and partners could be used as important endpoints in selected clinical trials.     

Expression of Ki-67—-A Proliferation-Associated Antigen—in Prostatic Cancer

The expression of the proliferation-associated antigen Ki-67 was studied in human prostatic cancer. the antigen was analyzed with an immuno-histochemical technique in TUR specimens. A correlation was seen between Ki-67 positivity and differentiation grade. All TUR specimens (15/15) with poorly differentiated carcinomas expressed the antigen. Moderately differentiated carcinomas constituted an intermediate group and slightly less than half of the cancers (12/27) were positive for the antigen. Only one of the highly differentiated carcinomas (1/12) expressed the antigen. All TUR specimens from patients with benign prostatic hyperplasia (8/8) were negative. the effect on Ki-67 positivity was also investigated in a human prostatic cancer heterotransplanted to nude mice and subjected to ionizing irradiation with or without concomitant estramustine treatment. the antigen expression was compared with that seen in tumour tissues from untreated mice and from mice treated with estramustine alone. A pronounced effect was seen in the combination treatment group with an approximately 50% reduction of the Ki-67 positive cells. the results are discussed in relation to prognosis and follow-up after radiation therapy and the possible use of estramustine in combination with radiation therapy.     

Radiosensitizing effect of estramustine in malignant gliomain vitro andin vivo

Summary Estramustine-phosphate (EMP), a combination of nornitrogen mustard and 17-estradiol, has been demonstrated to exert specific antiproliferative effects on human glioma cellsin vitro. The cytotoxic effect is, at least partially, mediated by inhibiting microtubule function. In this study the combined effect of EMP and radiation was evaluated in the human glioma cell-lines, 251-MG and 105-MG,in vitro, and in the rat glioma BT4Cin vitro andin vivo. In all cell-lines an additive effect of EMP and radiation was obtainedin vitro. Assuming equal effect of EMP is obtained in subsequent radiation fractions, the cell kill will be increased from 2–3 to 5–10 logs if delivering 30 fractions of 2 Gy combined with EMP. In the BT4C rat model the combined effect was found to be synergistic. Flow cytometry demonstrated an arrest in G2/M phase in all cell-lines after EMP treatment. This block in G2/M phase in addition to the previously demonstrated induction of free oxygen radicals, and the increase of blood flow with an assumed subsequent increase of oxygenation, might provide an explanation for the observed radiosensitizing effect of estramustine.     

Design of cytotoxic steroids for prostate cancer

Our object was to determine if the aromatic nucleus of estramustine (I) is optimal for binding affinity to prostate cytosolic proteins, and if C3 is the preferred position for the N-mustard carbamate moiety. To this end we have submitted 34 steroids for in vitro assay of binding affinity to total prostate cytosolic proteins. Our structures included aromatic and hydroaromatic steroids containing N-mustard carbamate and other substituents at C3, C6, C11, C16, C17, C20, and C21. Our results show that binding affinity to prostate proteins is optimally present in C3-nitrogen mustard carbamates attached directly to a totally planar aromatic ring as in (IV). Partial deviation from total planarity as in enol-carbamates (V) leads to some loss of binding affinity, which largely disappears in hydroaromatic structures (VI). Thus, our data lead to the Ring A aromatic structure (X) as a basis for the design of steroidal N-mustard carbamates with prostate selectivity. Preliminary in vivo studies using the Dunning R3327AT prostatic adenocarcinoma implanted in the Copenhagen rat generally support our in vitro data.     

Proteolytic cleavage of high-molecular-weight microtubule-associated proteins by the prostatic estramustine-binding protein

The rat prostatic estramustine-binding protein was found to inhibit assembly of microtubules in a concentration-dependent manner. The inhibition was caused by a proteolytic cleavage of the high-molecular-weight microtubule associated proteins (MAPs), as judged by sodium dodecyl sulfate-gel electrophoresis. A proteolytic fragment with a molecular weight of 199 kDa appeared, which remained bound to the assembled microtubules. Fragments of lower molecular weights (170, 149 kDa) were also found, but they did not bind to the assembled microtubules. Fragments with identical molecular weights were also found after incubation of purified MAP2 with the estramustine-binding protein, indicating that the fragments derive from MAP2. No proteolysis of tubulin, albumin, or casein was found. The estramustine-binding protein was found to be a Zn2+-dependent protease; it was inhibited by EDTA and reactivated by addition of 1 mM Zn2+. Its proteolytic activity was not affected by binding of the antimitotic drug estramustine.     

Approaches to prostatic cancer chemotherapy using the Dunning R3327H prostatic adenocarcinoma

Androgen-responsive cells: To determine if testosterone or dihydrotestosterone is the main trophic hormone of prostatic adenocarcinoma, we have treated Dunning R3327H prostatic adenocarcinoma-bearing rats with 6-methylene progesterone, which blocks conversion of testosterone to dihydrotestosterone. Copenhagen-Fisher rats were treated with steroid (20 mg/Kg daily) immediately following implantation of tumor and thereafter for 117 days. There was a 92% inhibition of growth of tumors and a lesser effect upon prostate and seminal vesicles. Tumor-free body weights remained unchanged. Both treated and untreated tumors had equivalent DNA content on a per weight basis. This result supports the thesis that prostatic adenocarcinoma requires dihydrotestosterone for growth. Androgen-insensitive cells: Advanced prostate cancer does not respond to endocrine therapy but is temporarily controlled by the cytotoxic steroid estramustine. The latter shows significant selective binding to prostatic protein. To develop chemotherapeutic agents that will control androgen-insensitive cells and possess improved selectivity for prostatic protein, we have studied a number of steroids for their ability to displace 3H-labeled estramustine from prostatic cytosolic proteins. Surprisingly, a carbamido substituent at the C17 position was found to confer significant binding affinity for prostatic estramustine-binding protein. Extension of this structural characteristic to the estramustine type of molecule is being studied.     

A randomized study of docetaxel and dexamethasone with low- or high-dose estramustine for patients with advanced hormone-refractory prostate cancer

OBJECTIVE: To test the combination of docetaxel with two different doses of estramustine in patients with hormone-refractory prostate cancer (HRPC), to improve response rates and to lower side-effects, as docetaxel-based chemotherapy is an increasing option for men with advanced HRPC, and alone or combined with estramustine, docetaxel improves median survival. PATIENTS AND METHODS: In all, 72 patients with metastatic HRPC were randomly assigned to receive docetaxel (70 mg/m(2) intravenously, on day 2 every 21 days) and estramustine (3 x 280 mg/day oral starting 1 day before docetaxel, for 5 consecutive days) for arm A, or estramustine (3 x 140 mg/day oral starting 1 day before docetaxel, for 3 consecutive days) for arm B. Premedication with oral dexamethasone at a total daily dose of 16 mg, in divided doses twice a day was administered in arm A on day 1-5 and in arm B on day 1-3. Initially, six cycles were administered. Chemotherapy was restarted after a significant increase in prostate-specific antigen (PSA) level. Patients were monitored for any measurable PSA response and toxicity. RESULTS: Between the arms there was no statistically significant difference in time to progression and overall survival. However, treatment B had less treatment-related toxicity than A. Independent prognostic variables were baseline factors like PSA level, haemoglobin level, Eastern Cooperative Oncology Group performance status, and bone pain at presentation. CONCLUSIONS: In this randomized phase II study the combination of docetaxel and estramustine had substantial activity in HRPC, with a significant incidence of severe toxicity, both haematological and not. Nevertheless, treatment-related toxicity was predictable and manageable. There was no better effect with a higher dose of estramustine with docetaxel than for a lower dose. There was a slight tendency to higher toxicity for high-dose estramustine but this was not statistically significant. The present results support the assertion that estramustine is not necessary in docetaxel-based treatment regimens.