Faculty Bibliography

The primary aims of this study were to evaluate the timecourse and dose response of microtubule bundle formationin peripheral blood mononuclear cells (PBMCs) and to correlate these data with BMS-247550 pharmacokinetics. The data presented here were obtained from 17 patients enrolled in a Phase I trial who received five dose levels of BMS-247550 (7.4-59.2 mg/m(2)), given as a 1-h infusion once every 3 weeks. Plasma drug exposure or area under the curve (AUC), and tubulin bundle formation in PBMCs were assessed in cycles 1 and 2. Similar analyses were also performed on tumor biopsies from one eligible patient. PBMCs exhibited dramatic microtubule bundle formation 1 h after infusion that declined by 24 h, showing a positive correlation with AUC((0-24)) for cycles 1 and 2. A similar pattern of tubulin bundle formation also was observed in a smaller proportion of breast tumor cells from one patient who exhibited a partial response to BMS-247550. This patient's tumor expressed multidrug resistance (MDR1) and MDR-associated protein (MRP1), and in addition poly(ADPribose) polymerase cleavage, a marker of cell death, was observed within 23 h after drug infusion. This patient was also heterozygous for a novel polymorphism at the extreme COOH terminus of beta-tubulin (Gly 437 Gly/Ser), although the relevance of the polymorphism to the response is unknown. In summary, microtubule bundle formation in PBMCs occurs within 1 h of treatment with BMS-247550 and is related to plasma AUC. Similar bundle formation was seen in one tumor sample, despite expression of MDR1 and MRP1. Cell death occurred 23 h after peak microtubule bundle formation in these tumor cells. These findings validate in vitro pharmacodynamic observations.

OBJECTIVE: The objective of this study was to verify the correlation between p53 immunostaining at initial diagnosis and at positive reassessment after completing platinum-based chemotherapy and to assess prognostic differences between patients whose tumors display positive immunostaining versus those that have negative immunostaining at such reassessment. METHODS: This study made use of samples from patients entered into a prospective randomized study of the Southwest Oncology Group (SWOG 8835) that treated patients with minimal residual disease at second-look laparotomy with either intraperitoneal (ip) mitoxantrone or fluorodeoxyuridine (FUDR). Unstained slides from tumor obtained at the initial diagnosis and at reassessment were retrospectively requested from individual institutions. The degree of nuclear staining was determined using the anti-p53 mouse monoclonal antibody Pab1801 and previously published techniques, with a cutoff of 10% or more staining of tumor cell nuclei for a positive result. Cox model regression analysis was performed for overall survival and progression-free survival, with p53 status, ip treatment, and baseline CA125 as independent variables. RESULTS: p53 determination was feasible in 22 patients both at diagnosis and at the second-look samples; 9 additional patients had only either sample available. Since concordance between the 10 negative and 12 positive immunostained samples was 100%, all 31 patients were considered in the Cox model. The death hazard ratio of p53-positive versus p53-negative patients was 4.18 (two-sided P value of 0.006). CONCLUSION: p53 immunostaining at second-look laparotomy correlates with the immunostaining at diagnosis. In this series confined to patients with minimal residual disease after initial therapy subjected to second-line intraperitoneal treatment, it appears to identify a poor prognostic (positive) subset for survival.

PURPOSE: To determine whether pegylated liposomal doxorubicin (PLD) has antitumor activity in pretreated patients with persistent or recurrent endometrial carcinoma and to define the nature and degree of toxicity of PLD. PATIENTS AND METHODS: Women with histologically documented recurrent or persistent measurable endometrial carcinoma and with failure of one prior treatment regardless of prior anthracycline therapy were enrolled. PLD was administered intravenously over a 1-hour period at a dose of 50 mg/m(2) every 4 weeks; the dosage was modified in accordance with observed toxicity. RESULTS: Of 46 patients entered, 42 were assessable for response, as three were declared ineligible on central pathology review and one was not assessable for response. Forty had received prior chemotherapy, 11 hormonal therapy, and 29 radiation therapy. Doxorubicin had been given to 32 patients, carboplatin with paclitaxel to six, carboplatin to one, and fluorouracil to one. Four patients had partial responses lasting 1.1, 2.1, 3.3, and 5.4 months; the overall response rate was 9.5% (95% confidence interval, 2.7% to 22.6%). Three of these responses (in liver and in lymph node) occurred in patients who had progressed after doxorubicin with either paclitaxel or cisplatin. The median number of courses was 2.5 (range, one to 14). Toxicity was generally mild: only 25 patients experienced leukopenia, with a median WBC count of 2,900 (range, 800 to 3,900) at nadir. The only grade 4 toxicities were one episode each of esophagitis, hematuria, and vomiting. The median overall survival was 8.2 months. CONCLUSION: PLD has only limited activity in pretreated advanced, recurrent endometrial cancer, but further trials in anthracycline-naive patients and in previously untreated patients are ongoing. Its toxicity profile should permit its use in combination with myelosuppressive drugs

We examined the role of neoadjuvant therapy in downstaging locally advanced gastric cancer. Preoperative staging was performed with a combination of CT scans, endoscopic ultrasonography and/or laparoscopy, and laparoscopic ultrasonography. Patients with T > or =3 tumors and/or node-positive disease by preoperative clinical staging were eligible for entry. Neoadjuvant therapy consisted of two cycles of CPT-11 (75 mg/m(2)) with cisplatin (25 mg/m(2)) weekly four times every 6 weeks. This was followed by resection with D2 lymph node dissection and two cycles of intraperitoneal chemotherapy with floxuridine and cisplatin. Twenty-two patients were entered into the study (4 with T3N0 disease and 18 with T3N1 disease). Induction chemotherapy was well tolerated with major toxicities being neutropenia and diarrhea. A median of 78%/75% of the planned dosage of CPT-11/cisplatin was delivered. Two patients withdrew consent during the first cycle and were lost to follow-up. One patient progressed to stage IV disease during induction chemotherapy and did not undergo surgery. Nineteen patients underwent surgery. One patient had undetected stage IV disease (liver) and underwent a palliative R2 resection. Of the 18 remaining patients, 17 had curative R0 resections and one had a palliative R1 resection. A median of 21 lymph nodes (range 1 to 121) were examined histologically. There was one postoperative death. Surgical morbidity did not appear to increase after the neoadjuvant regimen. The median postoperative length of hospital stay was 9 days (range 3 to 75 days). Postoperative pathologic staging yielded 16% T3 lesions compared to 85% before treatment based on clinical staging; postoperative American Joint Committee on Cancer staging yielded 37% stage IIIA disease compared to 70% stage IIIA before treatment. With a median follow-up of 15 months, median survival has not yet been reached. We conclude that CPT-11-based neoadjuvant therapy downstages locally advanced gastric cancer. Further follow-up is necessary to determine the ultimate impact of this combination therapy on recurrence and survival

BACKGROUND: Mullerianadenosarcoma is a rare pelvic malignancy that most commonly arises from the endometrium. These tumors are relatively insensitive to chemotherapy and radiation and are primarily treated by surgical resection. We report a case of mullerian adenosarcoma arising outside of the uterus from a background of endometriosis treated with a combination of surgical resection and medroxyprogesterone acetate. CASE: A 43-year-old woman with a history of endometriosis was diagnosed with advanced extrauterine mullerian adenosarcoma. After suboptimal tumor dubulking surgery she was treated with medroxyprogesterone acetate. Ten months postoperatively she remains without evidence of disease. CONCLUSION: Medroxyprogesterone acetate may be a useful drug in the treatment of advanced mullerian adenosarcoma

Treatment with the proteasome inhibitor, PS-341 resulted in concentration- and time-dependent effects on Bcl-2 phosphorylation and cleavage in H460 cells that coincided with the PS-341-induced G2-M phase arrest. The observed Bcl-2 cleavage paralleled the degree of PS-341-induced apoptosis but was detected to a similar extent with comparable concentrations of two other proteasome inhibitors (MG-132 and PSI). Calpain inhibitors, ALLM and ALLN, and the caspase inhibitors, Z-VAD and AC-YVAD did not induce BcI-2 phosphorylation and cleavage. Exposure to PS-341 resulted in an additional Mr 25,000 cleavage fragment of Bcl-2, whereas only a Mr 23,000 fragment was observed with other anticancer agents. The formation of the Mr 25,000 fragment was not prevented by caspase inhibitors unlike the Mr 23,000 fragment, which suggests mediation by a caspase-independent pathway. Cell fractionation studies revealed that the Bcl-2 cleaved fragments localize within membrane structures and was an early event (at approximately 12 h, posttreatment), and before the observed cleavage of poly(ADP-ribose) polymerase (PARP), beta-catenin, and DNA fragmentation (at approximately 36 h posttreatment). The Mr 23,000 Bcl-2 cleavage product was inhibited by the pan-caspase inhibitor and the inhibitors of capase-3, -8, -9; but the PARP cleavage was prevented only by the pan-caspase and caspase-3 inhibitors, which suggests that the Mr 23,000 Bcl-2 cleavage occurred at both the initiation and execution stages of apoptosis. The inhibition of the ubiquitin/proteasome pathway by PS-341 leads, at an early stage of apoptosis, to Bcl-2 phosphorylation and a unique proteolytic cleavage product, which are associated with G2-M phase arrest and the induction of apoptosis