Carsten-Oliver Schulz

Bortezomib increases osteoblast activity in myeloma patients irrespective of response to treatment

Abstract:  Objectives: Myeloma bone disease is a result of excessive osteoclast activation and impaired osteoblast function. Recent in vitro studies suggested that proteasome inhibitors might increase osteoblast function. Methods: We analyzed serum markers of osteoblast activity in 25 patients with multiple myeloma receiving bortezomib alone or in combination with dexamethasone. As control, serum samples from 58 consecutive myeloma patients receiving a therapy different than bortezomib (i.e. adriamycin/dexamethasone, melphalan/prednisone or thalidomide) were evaluated. The serum concentrations of bone‐specific alkaline phosphatase (BAP) and osteocalcin were quantified before initiation of treatment and after 3 months. Results: In patients treated with bortezomib, mean serum levels of osteocalcin significantly increased from 6.3 to 10.8 μg/L (P = 0.024), while mean BAP levels increased from 19.7 to 30.2 U/L (P < 0.0005). Of interest, the increase in BAP was significant both in responders and non‐responders. In contrast, the control group did not show a statistically significant change in BAP (24.8 U/L vs. 23.3 U/L) and osteocalcin (6.8 μg/L vs. 6.5 μg/L) before and after the treatment. Conclusion: These data show that treatment with bortezomib leads to enhanced markers of osteoblast activity in patients with myeloma. The comparison with the control group suggests that the effect on osteoblasts is unique to the proteasome inhibitor.

Breast Cancer-Associated Thrombotic Microangiopathy

Background: Thrombotic microangiopathy (TMA) is defined as thrombocytopenia and microangiopathic hemolytic anemia. Cancer-associated TMA, a rare but fatal condition, seems an entity distinct from classical thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS). Patients and Methods: All patients with breast cancer-associated TMA treated at our institution between 2003 and 2008 were analyzed retrospectively. To elucidate pathophysiological mechanisms, we measured the serum activity of the metalloprotease ADAMTS13. Results: 8 patients were identified. All showed bone marrow infiltration of breast cancer as well as thrombocytopenia, schistocytes, and hemolytic anemia. ADAMTS13 activity was mildly decreased in 4/6 patients (20–108%, normal range 30–120%), but none showed severely low levels as is characteristic of classical TTP. 6 patients were treated with anthracycline-containing fractionated chemotherapy, 5/6 patients experienced partial response. Overall survival was 13 months. Fractionated chemotherapy was well tolerated. Conclusions: Cancer-associated TMA has an underlying mechanism different from classical TTP. While bone marrow infiltration might be of major relevance, ADAMTS13 deficiency seems to be an epiphenomenon. Fractionated chemotherapy resulted in higher remission rates and comparatively long survival.

Primary chemotherapy with gemcitabine, liposomal doxorubicin and docetaxel in patients with locally advanced breast cancer: results of a phase I trial

The primary objective was to determine the optimal doses for gemcitabine (prolonged infusion), liposomal doxorubicin (Myocet) and docetaxel as primary (neoadjuvant) chemotherapy for locally advanced breast cancer. Secondary objectives included evaluation of the safety and efficacy of the regimen. Patients (n=19) with histologically confirmed stage II or III breast cancer were treated with liposomal doxorubicin (50–60 mg/m2) and docetaxel (60–75 mg/m2) on day 1, and gemcitabine as 4-h infusion (350–400 mg/m2) on day 4. Treatment was repeated every 3 weeks for a maximum of 6 cycles. The maximum tolerated doses were gemcitabine 350 mg/m2, liposomal doxorubicin 60 mg/m2 and docetaxel 75 mg/m2. Dose-limiting toxicities were stomatitis, diarrhea and infection. The predominant hematologic toxicity was mild-to-moderate myelosuppression with grade 3/4 neutropenia in 20% of cycles. Non-hematologic toxicity was generally mild, with no grade 4 toxicities being observed. Predominant non-hematologic toxicity was stomatitis, which occurred in 95% of patients. Grade 3 toxicities were reported for stomatitis, nausea, diarrhea, infection and constipation. No cases of cardiac, renal, pulmonary or neurotoxicity were observed. The clinical response rate was 83% and histologically confirmed, clinically complete remissions occurred in two patients (11%). We conclude that the combination of gemcitabine (prolonged infusion), liposomal doxorubicin and docetaxel is safe and highly effective in patients with locally advanced breast cancer as defined by maximum tolerated doses. The evaluated schedule is suitable for phase II studies.

Targeting multiple tyrosine kinase receptors with Dovitinib blocks invasion and the interaction between tumor cells and cancer-associated fibroblasts in breast cancer

A constitutive and dynamic interaction between tumor cells and their surrounding stroma is a prerequisite for tumor invasion and metastasis. Fibroblasts and myofibroblasts (collectively called cancer associated fibroblasts, CAFs) often represent the major cellular components of tumor stroma. Tumor cells secret different growth factors which induce CAFs proliferation and differentiation, and, consequently, CAFs secrete different chemokines, cytokines or growth factors which induce tumor cell invasion and metastasis. In this study we showed here that CAFs from breast cancer surgical specimens significantly induced the invasion of breast cancer cells in vitro. Most interestingly, the novel multiple tyrosine kinase inhibitor Dovitinib significantly blocked the CAFs-induced invasion of breast cancer cells by, at least in part, inhibition of the expression and secretion of CCL2, CCL5 and VEGF in CAFs. Inhibition of PI3K/Akt/mTOR signaling could be responsible for the effects of Dovitinib, since Dovitinib antagonized the promoted phosphorylated Akt after treatment with PDGF, FGF or breast cancer cell-conditioned media. Treatment with Dovitinib in combination with PI3K/Akt/mTOR signaling inhibitors Ly294002 or RAD001 resulted in additive inhibition of cell invasion. This is the first in vitro study to show that the multiple tyrosine kinase inhibitor has therapeutic activities against breast cancer metastasis by targeting both tumor cells and CAFs.

A Rare Case of Acute Myeloid Leukemia with a t(2;3) Chromosomal Translocation Characterized by Thrombophilia and Chemoresistance

We hereby report a case of acute myeloid leukemia with translocation t(2;3) and involvement of the ectopic virus integration site-1 (EVI1) gene. Like most other 3q26-related disorders reported thus far, we describe a phenotype with elevated platelet counts and dysmegakaryopoesis. The clinical course of our patient was complicated by symptomatic thrombophilia and chemoresistance. In addition, our case exhibited FLT3 (Fms-related tyrosine kinase 3) internal tandem duplication. Although anagrelide was successful in controlling elevated platelet counts, allogeneic stem cell transplantation failed to overcome chemoresistance due to simultaneous graft-versus-host-disease and relapse of acute myeloid leukemia. Given the dismal outcome of our case and previously reported cases, we propagate the implementation of targeted therapies to newly diagnosed patients with acute myeloid leukemia t(2;3). Preclinical models indicate drugs that plausibly target the EVI1-related molecular vulnerability as candidates for basket trials. Anagrelide exhibited a hopeful signal of activity in 3q26-related thrombocytosis and should be evaluated for implementation as supportive care.