Molecular pathways involved in the synergistic interaction of the PKCβ inhibitor enzastaurin with the antifolate pemetrexed in non-small cell lung cancer cells

Conventional regimens have limited impact against non-small cell lung cancer (NSCLC). Current research is focusing on multiple pathways as potential targets, and this study investigated molecular mechanisms underlying the combination of the PKCβ inhibitor enzastaurin with the multitargeted antifolate pemetrexed in the NSCLC cells SW1573 and A549. Pharmacologic interaction was studied using the combination-index method, while cell cycle, apoptosis induction, VEGF secretion and ERK1/2 and Akt phosphorylation were studied by flow cytometry and ELISAs. Reverse transcription–PCR, western blot and activity assays were performed to assess whether enzastaurin influenced thymidylate synthase (TS) and the expression of multiple targets involved in cancer signaling and cell cycle distribution. Enzastaurin-pemetrexed combination was highly synergistic and significantly increased apoptosis. Enzastaurin reduced both phosphoCdc25C, resulting in G2/M checkpoint abrogation and apoptosis induction in pemetrexed-damaged cells, and GSK3β and Akt phosphorylation, which was additionally reduced by drug combination (−58% in A549). Enzastaurin also significantly reduced pemetrexed-induced upregulation of TS expression, possibly through E2F-1 reduction, whereas the combination decreased TS in situ activity (>50% in both cell lines) and VEGF secretion. The effects of enzastaurin on signaling pathways involved in cell cycle control, apoptosis and angiogenesis, as well as on the expression of genes involved in pemetrexed activity provide a strong experimental basis to their evaluation as pharmacodynamic markers in clinical trials of enzastaurin-pemetrexed combination in NSCLC patients

In vitro study on the schedule-dependency of the interaction between pemetrexed, gemcitabine and irradiation in non-small cell lung cancer and head and neck cancer cells

<p>Abstract</p> <p>Background</p> <p>Based on their different mechanisms of action, non-overlapping side effects and radiosensitising potential, combining the antimetabolites pemetrexed (multitargeted antifolate, MTA) and gemcitabine (2',2'-difluorodeoxycytidine, dFdC) with irradiation (RT) seems promising. This <it>in vitro </it>study, for the first time, presents the triple combination of MTA, dFdC and irradiation using various treatment schedules.</p> <p>Methods</p> <p>The cytotoxicity, radiosensitising potential and cell cycle effect of MTA were investigated in A549 (NSCLC) and CAL-27 (SCCHN) cells. Using simultaneous or sequential exposure schedules, the cytotoxicity and radiosensitising effect of 24 h MTA combined with 1 h or 24 h dFdC were analysed.</p> <p>Results</p> <p>Including a time interval between MTA exposure and irradiation seemed favourable to MTA immediately preceding or following radiotherapy. MTA induced a significant S phase accumulation that persisted for more than 8 h after drug removal. Among different MTA/dFdC combinations tested, the highest synergistic interaction was produced by 24 h MTA followed by 1 h dFdC. Combined with irradiation, this schedule showed a clear radiosensitising effect.</p> <p>Conclusions</p> <p>Results from our <it>in vitro </it>model suggest that the sequence 24 h MTA → 1 h dFdC → RT is the most rational design and would, after confirmation in an <it>in vivo </it>setting, possibly provide the greatest benefit in the clinic.</p

A preclinical evaluation of pemetrexed and irinotecan combination as second-line chemotherapy in pancreatic cancer

Gemcitabine (GEM)-based chemotherapy is regarded as the standard treatment of pancreatic adenocarcinoma, but yields a very limited disease control. Very few studies have investigated salvage chemotherapy after failure of GEM or GEM-containing chemotherapy and preclinical studies attempting to widen the therapeutic armamentarium, not including GEM, are warranted. MIA PaCa2, CFPAC-1 and Capan-1 pancreatic cancer cell lines were treated with GEM, fluouracil (5-FU), docetaxel (DCT), oxaliplatin (OXP), irinotecan (CPT-11), pemetrexed (PMX) and raltitrexed (RTX) as single agent. Pemetrexed, inducing apoptosis with IC50s under the Cmax in the three lines tested, appeared the most effective drug as single agent. Based on these results, schedule- and concentration-dependent drug interactions (assessed using the combination index) of PMX/GEM, PMX/DCT and PMX–CPT-11 were evaluated. The combinatory study clearly indicated the PMX and CPT-11 combination as the most active against pancreatic cancer. To confirm the efficacy of PMX–CPT-11 combination, we extended the study to a panel of 10 pancreatic cancer cell lines using clinically relevant concentrations (PMX 10 μM; CPT-11 1 μm). In eight of 10 lines, the PMX–CPT-11 treatment significantly reduced cell recovery and increased both the subG1 and caspase 3/7 fraction. After a 5-day wash out period, an increased fraction of subG1 and caspase3/7 persisted in PMX–CPT-11-pretreated cell lines and a significant reduction in the clonogenicity capacity was evident. Finally, in vivo, the PMX/CPT-11 combination showed the ability to inhibit xenograft tumours growth as second-line therapy after GEM treatment. The PMX and CPT-11 combination displays a strong schedule-independent synergistic cytotoxic activity against pancreatic cancer, providing experimental basis for its clinical testing as salvage chemotherapy in pancreatic cancer patients

In vitro synergistic cytotoxicity of gemcitabine and pemetrexed and pharmacogenetic evaluation of response to gemcitabine in bladder cancer patients

The present study was performed to investigate the capability of gemcitabine and pemetrexed to synergistically interact with respect to cytotoxicity and apoptosis in T24 and J82 bladder cancer cells, and to establish a correlation between drug activity and gene expression of selected genes in tumour samples. The interaction between gemcitabine and pemetrexed was synergistic; indeed, pemetrexed favoured gemcitabine cytotoxicity by increasing cellular population in S-phase, reducing Akt phosphorylation as well as by inducing the expression of a major gemcitabine uptake system, the human equilibrative nucleoside transporter-1 (hENT1), and the key activating enzyme deoxycytidine kinase (dCK) in both cell lines. Bladder tumour specimens showed an heterogeneous gene expression pattern and patients with higher levels of dCK and hENT1 had better response. Moreover, human nucleoside concentrative transporter-1 was detectable only in 3/12 patients, two of whom presented a complete response to gemcitabine. These data provide evidence that the chemotherapeutic activity of the combination of gemcitabine and pemetrexed is synergistic against bladder cancer cells in vitro and that the assessment of the expression of genes involved in gemcitabine uptake and activation might be a possible determinant of bladder cancer response and may represent a new tool for treatment optimization

In vitro genotoxicity and cytotoxicity of a particular combination of pemetrexed and cefixime in human peripheral blood lymphocytes

This study aims to find the genotoxic and cytotoxic effects of a particular combination of pemetrexed (PMX) and cefixime (CFX) in human peripheral blood lymphocytes. Chromosome aberration (CA), sister chromatid exchange (SCE), and micronucleus (MN) tests were used to assess genotoxicity. Whereas, the cytotoxicity was evaluated by using mitotic index (MI), proliferation index (PI), and nuclear division index (NDI). Our tests were proceeded with concentrations of 12.5 + 450, 25 + 800, 37.5 + 1150, and 50 + 1500 μg/mL of a mixture of PMX and CFX separately for 24 hr and 48 hr. The combination of PMX + CFX did not induce the CA or SCE in human peripheral blood lymphocytes when compared with both the control and the solvent control. MN in human peripheral blood lymphocytes was not significantly increased after treatment with a particular combination of PMX + CFX. However, PMX + CFX significantly decreased the MI, PI and NDI at all concentrations for 24- and 48-hr treatment periods when compared with both controls. Generally, PMX + CFX inhibited cell proliferation more than positive control (MMC) and showed a higher cytotoxic effect than MMC at both treatment periods. These results were compared with individual effects of PMX and CFX. As a result, it was observed that a particular combination of PMX + CFX was not genotoxic. However, the combination synergistically increase cytotoxicity in human peripheral blood lymphocytes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40064-015-0803-3) contains supplementary material, which is available to authorized users

Missing non-Western voices on social justice for education : a postcolonial perspective on traditions of marginalized communities

This chapter reviews the theories and development of a number of non-Western philosophical and legal social justice traditions that have been marginalized in the literature, adopting primarily a postcolonial perspective on how they can contribute to education, transcending colonizer distortions of knowledge to present and draw implications from bodies of knowledge that have been removed from the dominating international literature. This approach is accompanied by a critique of globalization that has, according to many authors, created a hegemonic position for primarily Anglo-American systems in this respect including the view of “epistemicide,” imperialism, “symbolic violence,” and neocolonization, particularly in relation to the right to culture as a social justice principle. Various forms of colonization, including that under the current globalization period, produce cultural hierarchies of values and knowledge, or even expunge cultural and knowledge traditions. This chapter examines selected humanistic traditions of social justice that have existed for centuries, long pre-dating the modern period, focusing on those that have suffered an injustice in their suppression and distortion through a Bourdieuian “symbolic” violence applying not only to the knowledge that is suppressed, expunged, or lost through colonization and globalization and the cultural and intellectual capital they carry but also the identities, values, and traditional social institutions from which they are derived. The first section examines the conceptions and practices of social justice established in ancient Mesopotamia that provides the historical foundation to many later systems. The second presents the Confucian system of social justice as a foundation to the just society that has informed administration, education, and the principles of justice of a number of countries consisting of equitable distribution, equal opportunities, the rights of individuals and the principle of equity. The next section examines the Islamic social justice tradition consisting of distributive, retributive, and fairness and equity and the aim of piety to correct injustices, individually and collectively and establish equal rights for women and men in many spheres and the role of education in emphasizing the role of mind in its critical and reasoning capacities and reason in the formation of character, morality, and the human community with a strong emphasis on education and becoming learned. Finally, a representative selection of indigenous systems of social justice are examined where principles of individual rights and obligations to others and nature carried with them obligations in how others are treated and cared for due to stronger collective rather than individualistic values

Gendered landscapes: the politics and processes of inquiry and of negotiating interests in land

It is 1789, one year after British colonisation began. Arthur Phillip, Governor of the British settlement of New South Wales, has befriended Bennelong, a local Aboriginal man whose name has since been etched into wider Australia’s social and physical history by the area which bears his name at Bennelong Point in Sydney. Less well-known is Bennelong’s wife, Barangaroo; she is pregnant. One day Bennelong approaches Governor Phillip and requests permission for his and Barangaroo’s child to be born at Government House. Such a request is based on Indigenous custom whereby the site of one’s birth becomes one of the ways in which an association to land is established. By giving birth at Government House, Barangaroo and Bennelong will, in accordance with their own beliefs and practices, provide their child with rights to an important piece of land, not only as a Dreaming site but also as a potential ‘increase site’, an area where British resources are thought to be plentiful. Governor Phillip, who has been incorporated into the kinship system by Bennelong and Barangaroo, refuses on perhaps well-meaning but naive grounds. In his view, Barangaroo will be better off giving birth at a nearby hospital away from Government House. Governor Phillip cannot agree to the request because he believes that 158Barangaroo will be more comfortable at the hospital. Archival records do not show where Barangaroo eventually gave birth but she is sighted some days later wandering the settlement with a newborn child in her arms (Grimshaw et al., 1994, pp. 9-11)