Discovery of a ZIP7 inhibitor from a Notch pathway screen

The identification of activating mutations in NOTCH1 in 50% of T cell acute lymphoblastic leukemia has generated interest in elucidating how these mutations contribute to oncogenic transformation and in targeting the pathway. A phenotypic screen identified compounds that interfere with trafficking of Notch and induce apoptosis via an endoplasmic reticulum (ER) stress mechanism. Target identification approaches revealed a role for SLC39A7 (ZIP7), a zinc transport family member, in governing Notch trafficking and signaling. Generation and sequencing of a compound-resistant cell line identified a V430E mutation in ZIP7 that confers transferable resistance to the compound NVS-ZP7-4. NVS-ZP7-4 altered zinc in the ER, and an analog of the compound photoaffinity labeled ZIP7 in cells, suggesting a direct interaction between the compound and ZIP7. NVS-ZP7-4 is the first reported chemical tool to probe the impact of modulating ER zinc levels and investigate ZIP7 as a novel druggable node in the Notch pathway.

Characterization of activating mutations of NOTCH3 in T-cell acute lymphoblastic leukemia and anti-leukemic activity of NOTCH3 inhibitory antibodies

Notch receptors have been implicated as oncogenic drivers in several cancers, the most notable example being NOTCH1 in T-cell acute lymphoblastic leukemia (T-ALL). To characterize the role of activated NOTCH3 in cancer, we generated an antibody that detects the neo-epitope created upon gamma-secretase cleavage of NOTCH3 to release its intracellular domain (ICD3), and sequenced the negative regulatory region (NRR) and PEST domain coding regions of NOTCH3 in a panel of cell lines. We also characterize NOTCH3 tumor-associated mutations that result in activation of signaling and report new inhibitory antibodies. We determined the structural basis for receptor inhibition by obtaining the first co-crystal structure of a NOTCH3 antibody with the NRR protein and defined two distinct epitopes for NRR antibodies. The antibodies exhibit potent anti-leukemic activity in cell lines and tumor xenografts harboring NOTCH3 activating mutations. Screening of primary T-ALL samples reveals that two of 40 tumors examined show active NOTCH3 signaling. We also identified evidence of NOTCH3 activation in 12 of 24 patient-derived orthotopic xenograft models, two of which exhibit activation of NOTCH3 without activation of NOTCH1. Our studies provide additional insights into NOTCH3 activation and offer a path forward for identification of cancers that are likely to respond to therapy with NOTCH3 selective inhibitory antibodies.

Reduction of chemotherapy-induced febrile leucopenia by prophylactic use of ciprofloxacin and roxithromycin in small-cell lung cancer patients: an EORTC double-blind placebo-controlled phase III study

BACKGROUND

CDE (cyclophosphamide, doxorubicin, etoposide) is one of the standard chemotherapy regimens in the treatment of small-cell lung cancer (SCLC), with myelosuppression as dose-limiting toxicity. In this trial the impact of prophylactic antibiotics on incidence of febrile leucopenia (FL) during chemotherapy for SCLC was evaluated.

PATIENTS AND METHODS

Patients with chemo-naïve SCLC were randomized to standard-dose CDE (C 1,000 mg/m2 day 1, D 45 mg/m2 day 1, E 100 mg/m2 days 1-3. i.v., q 3 weeks, x5) or to intensified CDE chemotherapy (125% dose, q 2 weeks, x4, with filgrastim 5 microg/kg/day days 4-13) to assess the impact on survival (n = 240 patients). Patients were also randomized to prophylactic antibiotics (ciprofloxacin 750 mg plus roxithromycin 150 mg, bid. days 4-13) or to placebo in a 2 x 2 factorial design (first 163 patients). This manuscript focuses on the antibiotics question.

RESULTS

The incidence of FL during the first cycle was 25% of patients in the placebo and 11% in the antibiotics arm (P = 0.010; 1-sided), with an overall incidence through all cycles of 43% vs. 24% respectively (P = 0.007; 1-sided). There were less Gram-positive (12 vs. 4), Gram-negative (20 vs. 5) and clinically documented (38 vs. 15) infections in the antibiotics arm. The use of therapeutic antibiotics was reduced (P = 0.013; 1-sided), with less hospitalizations due to FL (31 vs. 17 patients, P = 0.013: 1-sided). However, the overall number of days of hospitalization was not reduced (P = 0.05; 1-sided). The number of infectious deaths was nil in the antibiotics vs. five (6%) in the placebo arm (P = 0.022; 2-sided).

CONCLUSIONS

Prophylactic ciprofloxacin plus roxithromycin during CDE chemotherapy reduced the incidence of FL, the number of infections, the use of therapeutic antibiotics and hospitalizations due to FL by approximately 50%, with reduced number of infectious deaths. For patients with similar risk for FL, the prophylactic use of antibiotics should be considered.

Gemcitabine and cisplatin as induction regimen for patients with biopsy-proven stage IIIA N2 non-small-cell lung cancer: a phase II study of the European Organization for Research and Treatment of Cancer Lung Cancer Cooperative Group (EORTC 08955)

PURPOSE

Our objective was to better define the activity/feasibility of gemcitabine/cisplatin (GC) as induction chemotherapy in patients with stage IIIA N2 non-small-cell lung cancer (NSCLC) followed by surgery or radiotherapy within a large, ongoing comparative study (EORTC 08941).

PATIENTS AND METHODS

Forty-seven chemotherapy-naive patients with NSCLC, median age of 58 years, stage IIIA N2 disease, World Health Organization performance status of 0 or 1, and the ability to tolerate a pneumonectomy received gemcitabine 1,000 mg/m(2) on days 1, 8, and 15 and cisplatin 100 mg/m(2) on day 2, every 4 weeks. Patients received induction chemotherapy (three cycles) before re-evaluation and randomization to surgery or radiotherapy.

RESULTS

Grade 3/4 thrombocytopenia, the main hematologic toxicity, occurred in 60% of patients but was not associated with bleeding. Full-dose gemcitabine was given in 48% of the courses. Severe nonhematologic toxicity was uncommon. Two patients with preexisting, autoimmune pulmonary fibrosis had deterioration of pulmonary function after radiotherapy. Thirty-three (70.2%; 95% confidence interval, 55.1% to 82.7%) of the 47 eligible patients had objective responses (three complete responses and 30 partial responses). Mediastinal nodes were tumor-free after induction therapy in 53% of cases. Resections were considered complete in 71% of the patients who underwent thoracotomy after induction therapy. Median survival for all recruited patients (N = 53) was 18.9 months, with an estimated 1-year survival rate of 69%.

CONCLUSION

In patients with N2 stage IIIA NSCLC, GC is a highly active and well-tolerated induction regimen. GC should be explored in combination with surgery or radiotherapy in stage I and II patients.

Long term survival of a patient with malignant pleural mesothelioma as a late complication of radiotherapy for Hodgkin's disease treated with 90yttrium-silicate

A case of malignant pleural mesothelioma (PM) 24 years after thoracic radiotherapy for Hodgkin's disease is presented. As primary treatment and to relieve symptoms of dyspnea secondary to pleural effusion a thoracic drain was installed, followed by intracavitary radiation therapy with 90yttrium-silicate. Minor complaints of fever and a dry cough as a side-effect of this treatment were effectively treated with prednisone during 2 weeks. The patient remains in a good clinical condition now 6 years after diagnosis. Considering the few therapeutic options the use of 90yttrium-silicate intrapleural installation could be propagated as a safe and effective antitumour treatment for a selected group of patients with malignant PM.

Congenital gastric teratoma in Wiedemann-Beckwith syndrome

Wiedemann-Beckwith syndrome (WBS) may be associated with abdominal tumors, including Wilms tumor, adrenocortical carcinoma, hepatoblastoma, gonadoblastoma, rhabdomyosarcoma, and neuroblastoma. We report on a newborn infant with WBS and a congenital teratoma of the stomach. This is the sole report of any teratoma being associated with WBS and also the first report of a tumor present at birth and visible prenatally in WBS. At birth this infant boy had the diagnostic findings of WBS with macroglossia, ear lobule creases and pits, nevus flammeus, and omphalocele, and an abdominal mass. Abnormalities were detected prenatally when ultrasound examination showed placental overgrowth, polyhydramnios, omphalocele, and posterior abdominal calcifications. Resection of the mass and partial gastrectomy were performed at age 10 days; histologic study showed an immature grade-II teratoma containing a mixture of mature and immature tissues from all germ layers. Results of cytogenetic studies of blood and teratoma were normal (46,XY). This congenital gastric teratoma in a newborn boy with classical WBS may represent either a tumor or an included twin. We discuss its implications for the association of WBS with neoplasia and monozygotic (MZ) twinning, review various neoplasias associated with WBS, and consider pathogenetic mechanisms.