Crizotinib acts as ABL1 inhibitor combining ATP-binding with allosteric inhibition and is active against native BCR-ABL1 and its resistance and compound mutants BCR-ABL1T315I and BCR-ABL1T315I-E255K.

Resistance remains the major clinical challenge for the therapy of Philadelphia chromosome-positive (Ph+) leukemia. With the exception of ponatinib, all approved tyrosine kinase inhibitors (TKIs) are unable to inhibit the common "gatekeeper" mutation T315I. Here we investigated the therapeutic potential of crizotinib, a TKI approved for targeting ALK and ROS1 in non-small cell lung cancer patients, which inhibited also the ABL1 kinase in cell-free systems, for the treatment of advanced and therapy-resistant Ph+ leukemia. By inhibiting the BCR-ABL1 kinase, crizotinib efficiently suppressed growth of Ph+ cells without affecting growth of Ph- cells. It was also active in Ph+ patient-derived long-term cultures (PD-LTCs) independently of the responsiveness/resistance to other TKIs. The efficacy of crizotinib was confirmed in vivo in syngeneic mouse models of BCR-ABL1- or BCR-ABL1T315I-driven chronic myeloid leukemia-like disease and in BCR-ABL1-driven acute lymphoblastic leukemia (ALL). Although crizotinib binds to the ATP-binding site, it also allosterically affected the myristol binding pocket, the binding site of GNF2 and asciminib (former ABL001). Therefore, crizotinib has a seemingly unique double mechanism of action, on the ATP-binding site and on the myristoylation binding pocket. These findings strongly suggest the clinical evaluation of crizotinib for the treatment of advanced and therapy-resistant Ph+ leukemia.

Platinum (IV)-fatty acid conjugates overcome inherently and acquired Cisplatin resistant cancer cell lines: an in-vitro study.

BACKGROUND: Platinum-based drugs are used as cancer chemotherapeutics for the last 40 years. However, drug resistance and nephrotoxicity are the major limitations of the use of platinum-based compounds in cancer therapy. Platinum (IV) complexes are believed to act as platinum prodrugs and are able to overcome some of platinum (II) limitations. METHODS: A number of previously sensitized platinum (IV) complexes were evaluated for their anti-cancer activity by monitoring ability to affect proliferation, clonigenicity and apoptosis induction of Cisplatin sensitive and resistant cancer cells. In addition, the uptake of Cisplatin and the platinum (IV) derivatives to Cisplatin sensitive and resistant cancer cells was monitored. RESULTS: The bis-octanoatoplatinum (IV) complex (RJY13), a Cisplatin derivative with octanoate as axial ligand, exhibited strong anti-proliferative effect on the Cisplatin resistant and sensitive ovarian cells, A2780cisR and A2780, respectively. Moreover, RJY13 exhibited good activity in inhibiting clonigenicity of both cells. Anti-proliferative activity of RJY13 was mediated by induction of apoptosis. Interestingly, a bis-lauratopaltinum (IV) complex (RJY6) was highly potent in inhibiting clonigenicity of both Cisplatin sensitive and Cisplatin resistant cells, however, exhibited reduced activity in assays that utilize cells growing in two dimensional (2D) conditions. The uptake of Cisplatin was reduced by 30% in A2780 in which the copper transporter-1 (Ctr1) was silenced. Moreover, uptake of RJY6 was marginally dependent on Ctr1, while uptake of RJY13 was Ctr1-independent. CONCLUSIONS: Our data demonstrated the potential of platinum (IV) prodrugs in overcoming acquired and inherited drug resistance in cancer cell lines. Moreover, our data demonstrated that the uptake of Cisplatin is partially dependent on Ctr1 transporter, while uptake of RJY6 is marginally dependent on Ctr1 and RJY13 is Ctr1-independent. In addition, our data illustrated the therapeutic potential of platinum (IV) prodrugs in cancer therapy.

Oleylamine-carbonyl-valinol inhibits auto-phosphorylation activity of native and T315I mutated Bcr-Abl, and exhibits selectivity towards oncogenic Bcr-Abl in SupB15 ALL cell lines.

Chronic myeloid leukemia (CML) is characterized by the presence of p210(Bcr-Abl) which exhibits an abnormal kinase activity. Selective Abl kinase inhibitors have been successfully established for the treatment of CML. Despite high rates of clinical response, CML patients can develop resistance against these kinase inhibitors mainly due to point mutations within the Abl protein kinase domain. Previously, we have identified oleic acid as the active component in the mushroom Daedalea gibbosa that inhibited the kinase activity of Bcr-Abl. Here, we report that the oleyl amine derivatives, S-1-(1-Hydroxymethyl-2-methyl-propyl)-3-octadec-9-enyl-urea [oleylaminocarbonyl-L-N-valinol,oroleylaminocarbonyl-S-2-isopropyl-N-ethanolamine,oleylamine-carbonyl-L-valinol] (cpd 6) and R-1-(1-Hydroxymethyl-2-methyl-propyl)-3-octadec-9-enyl-urea [oleylamineocarbonyl-D-N-valinol, oleylaminocarbonyl-R-2-isopropyl-N-ethanolamine, or oleylamine-carbonyl-D-valinol] (cpd 7), inhibited the activity of the native and T315I mutated Bcr-Abl. Furthermore, cpd 6 and 7 exhibited higher activity towards the oncogenic Bcr-Abl in comparison to native c-Abl in SupB15 Ph-positive ALL cell line.

Safety of herbal medicine use during chemotherapy in patients with ovarian cancer: a "bedside-to-bench" approach.

In this study, we explored herbal supplements used by patients during chemotherapy and test for herb-drug interactions and response of cancer cells to treatment. Patients with gynecological cancer referred to a complementary and integrative medicine (CIM) service were asked about their use of herbal medicine during chemotherapy. The leading five clinically relevant herbs selected for cytotoxicity analysis included the following: wheatgrass (Triticum aestivum), European mistletoe (Viscum album), ginger (Zingiber officinale), Ephedra (Ephedra campylopoda), and Oriental mistletoe (Viscum cruciatum). Cytotoxicity was examined using XTT assays in cisplatin-sensitive and resistant ovarian cancer cell lines (A2780, A2780CisR), and non-cancer kidney cells (HEK-293). The effect of the selected herbs on carboplatin and paclitaxel cytotoxicity was tested as well. Pro-apoptotic effects were tested using Poly(ADP-ribose) polymerase (PARP) cleavage. Of 98 patients referred to the CIM service, 42 (42.9%) reported using/intending to use herbal products during chemotherapy. European mistletoe and ginger exhibited significant anti-cancer activity in cisplatin-sensitive and resistant ovarian cells. Wheatgrass and ephedra reduced cytotoxicity of carboplatin on cisplatin-sensitive ovarian cancer cells, while ginger, European and Oriental mistletoe increased chemosensitivity in both cancer cell lines. Wheatgrass, European mistletoe, and ginger increased sensitivity to cisplatin-resistant cells treated with carboplatin and paclitaxel. No effect was observed with the addition of any of the herbs on non-cancerous embryonic kidney cells (HEK-293). Herbal medicine use by patients with ovarian cancer may influence anti-cancer activity of chemotherapy. Integrative physicians can provide "bedside-to-bench" guidance on the safety of these products.

Ectopic Expression of Snail and Twist in Ph+ Leukemia Cells Upregulates CD44 Expression and Alters Their Differentiation Potential.

Philadelphia chromosome-positive (Ph+) leukemia is characterized by reciprocal translocation between chromosomes 9 and 22. The resultant BCR/ABL fusion protein displays constitutive tyrosine kinase activity, leading to the induction of aberrant proliferation and neoplastic transformation. The bone marrow (BM) microenvironment is tumor-promoting, and contributes to disease recurrence in Ph+ leukemia. Activity in the BM microenvironment is mediated by several cellular compartments, extracellular matrix, various soluble factors including transforming growth factor beta 1 (TGF-ß1), and the hypoxic conditions in the BM niche. TGF-ß1 is released during bone remodeling and plays a role in maintaining leukemic stem cells, as well as being implicated in the epithelial-mesenchymal transition (EMT) process in most solid tumors. Although EMT is largely implicated in epithelial tumors, recent findings argue for an EMT-like process in leukemia as well. The surface receptor CD44 is involved in cell adhesion, cell migration, and homing of normal and malignant hematopoietic stem cells. Elevation of CD44 expression is considered a marker for a worse prognosis in most hematological malignancies. We explored the functions of Snail and Twist1 in Ph+ leukemia. We showed that ectopic expression of Snail and, to a lesser extent, Twist1, upregulates CD44 expression that is ß-catenin-dependent. Moreover, the presence of Snail or Twist1 partially blocked phorbol 12-myristate 13-acetate-induced megakaryocyte differentiation, while that of Twist significantly altered imatinib-induced erythroid differentiation. Thus EMT modulators affected proliferation, CD44 gene expression and differentiation ability of Ph+ leukemia cells.

Oleic acid is the active component in the mushroom Daedalea gibbosa inhibiting Bcr-Abl kinase autophosphorylation activity.

The hallmark of chronic myeloid leukemia (CML) is the abnormal activity of p210(Bcr-Abl) kinase. Selective kinase inhibitors such as imatinib or nilotinib have been established successfully for the treatment of CML. Despite high rates of clinical response, CML patients can develop resistance to these kinase inhibitors mainly due to point mutations within the Abl kinase domain of the fusion protein. Previously, we reported that a crude extract of the mushroom Daedalea gibbosa inhibited kinase activity of Bcr-Abl kinase. Here we report on the identification of the active component of Daedalea gibbosa, oleic acid, which inhibited Bcr-Abl kinase autophosphorylation in Ba/F3 cells and exhibited anti-CML activity in a BCR/ABL-positive mouse model.