Publications by authors named "Gabriela B Iwanski"

We investigated the use of cucurbitacin B, a plant-derived tetracyclic triterpenoid, as a single agent or in combination with methotrexate (MTX) for human osteosarcoma (OS) treatment. Cucurbitacin B showed antiproliferative activity against seven human OS cell lines in vitro accompanying G2/M cell cycle arrest, apoptosis, and inhibition of ERK, Akt, and mTOR proteins. Cucurbitacin B in combination with MTX synergistically inhibited OS cell growth in vitro.

View Article and Find Full Text PDF

Background And Purpose: Pancreatic cancer is a highly aggressive malignancy, and improvement in systemic therapy is necessary to treat this frequently encountered metastatic disease. The current targeted agents used in combination with gemcitabine improved objective response rates, but with little or no improvements in survival and also increased toxicities in pancreatic cancer patients. Recently, we showed that the triterpenoid cucurbitacin B inhibited tumour growth in pancreatic cancer cells by inhibition of the JAK/STAT pathway, and synergistically increased antiproliferative effects of gemcitabine in vitro.

View Article and Find Full Text PDF

Cucurbitacins and their derivatives are triterpenoids found in medicinal plants known for their diverse pharmacological and biological activities, including anticancer effects, throughout human history. Although initial attention to cucurbitacin as a potential anticancer drug withered for decades, recent discoveries showing that cucurbitacin is a strong STAT3 (Signal Transducers and Activators of Transcription-3) inhibitor have reclaimed the attention of the drug industry one more time. There is increasing evidence showing that some cucurbitacins not only inhibit the JAK-STAT pathway, but also affect other signaling pathways, such as the MAPK pathway, which are also known to be important for cancer cell proliferation and survival.

View Article and Find Full Text PDF

Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) including polycythemia vera, essential thrombocythemia, and primary myelofibrosis show an inherent tendency for transformation into leukemia (MPN-blast phase), which is hypothesized to be accompanied by acquisition of additional genomic lesions. We, therefore, examined chromosomal abnormalities by high-resolution single nucleotide polymorphism (SNP) array in 88 MPN patients, as well as 71 cases with MPN-blast phase, and correlated these findings with their clinical parameters. Frequent genomic alterations were found in MPN after leukemic transformation with up to 3-fold more genomic changes per sample compared with samples in chronic phase (P < .

View Article and Find Full Text PDF

Pancreatic cancer is an aggressive malignancy that is generally refractory to chemotherapy, thus posing experimental and clinical challenges. In this study, the antiproliferative effect of the triterpenoid compound cucurbitacin B was tested in vitro and in vivo against human pancreatic cancer cells. Dose-response studies showed that the drug inhibited 50% growth of seven pancreatic cancer cell lines at 10(-7) mol/L, whereas clonogenic growth was significantly inhibited at 5 x 10(-8) mol/L.

View Article and Find Full Text PDF

Recently, higher extramedullary relapse rates following allogeneic stem cell transplantation (SCT) in myeloid malignancies were reported e.g. because of selection of poor-risk patients.

View Article and Find Full Text PDF