The most widely transfused blood component is red blood cells (RBCs), and voluntary donation is the main resource for RBC transfusion. In the UK, 7,000 units of RBCs are transfused daily but this life-saving cell therapy is completely dependent on donors and there are persistent problems associated with transfusion transmitted infections and in blood group compatibility. Furthermore, the quality, safety and efficiency of donated RBCs gradually decrease with storage time. A number of novel sources of RBCs are being explored including the production of RBCs from adult haematopoietic progenitor cells, erythroid progenitor cell lines and induced pluripotent stem cells (iPSCs). The iPSC source could essentially provide a limitless supply and a route to producing cells that are matched to the recipient. A number of protocols have been described to produce mature RBCs from human pluripotent stem cells but they are relatively inefficient and would be difficult to scale up to the levels required for clinical translation. We tested and evaluated a defined feeder- and serum-free differentiation protocol for deriving erythroid cells from hiPSCs. RBC production was not efficient, the cells that were produced did not enucleate efficiently and they expressed embryonic rather than adult globin. We hypothesised that the production of RBCs from iPSCs could be enhanced by enforced expression of erythroid-specific transcription factors (TFs). Previous studies had demonstrated that Krüppel-like factor 1 (KLF1) plays an important role in RBC development and maturation so we generated iPSC lines expressing a tamoxifen-inducible KLF1-ERT2 fusion protein. Using zinc finger nuclease technology, we targeted the expression cassette to the AAVS1 locus to ensure consistent expression levels and to avoid integration site specific effects and/or silencing. These iKLF1 iPSCs were applied to our defined RBC differentiation protocol and the activity of KLF1 was induced by adding tamoxifen. Activation of KLF1 from day 10 accelerated erythroid differentiation and maturation with an increase in the proportion of erythroblasts, a higher level of expression of erythroid genes associated with maturation and an apparently more robust morphology. However, KLF1 activation had an anti-proliferation effect resulting in significantly less cell generated overall and HPLC analysis demonstrated that KLF1-activated cells expressed higher levels of embryonic globin compared to control iPSCs-derived cells. Many of the effects that were observed when KLF1 was activated from day 10 were not observed when activated from day 18. We therefore concluded that activation of exogenous KLF1 is able to promote erythroid cell production and maturation in progenitors (day 10) but not at the later stage of erythropoiesis (day 18). We hypothesised that KLF1 might require a co-factor to regulate RBC maturation and adult globin expression at the later stage of erythropoiesis. The TF, B-cell lymphoma/leukaemia 11a (BCL11A), plays a key role in the suppression of foetal globin expression, thereby completing globin switching to adult globin. Preliminary data showed that iPSC-derived erythroid cells were able to express adult globin when transduced with a BCL11A-expressing lentiviral-vector. Based on that finding we then generated an iPSC line expressing tamoxifen-inducible BCL11AERT2 and KLF1-ERT2 fusion proteins, applied this iBK iPSC line to our differentiation protocol. Activation of both TFs from day 18 slightly increased the expression of genes associated with RBC maturation and the inclusion of BCL11A appeared to eliminate the anti-proliferation effect of KLF1. Most importantly, activation of both BCL11A and KLF1 from day 18 of the differentiation protocol increased the production of α- globin (foetal / adult globin) indicating that some definitive-like erythroid cells might be generated by activation of both TFs at the later stage of erythroid differentiation. Collectively, these findings demonstrate that enforced expression of erythroid TFs could be a useful strategy to enhance RBC maturation from iPSCs.

[pt] Este trabalho apresenta a síntese e caracterização de 11-tosil-6,6a,11, 11-tetraidro-5H-benzo[a]carbazois análogos ao LQB223, um composto previamente sintetizado em nosso grupo de pesquisa que tem ação anticâncer e antileishmanial in vitro e ação antimalarial in vitro e in vivo. A etapa chave da reação para a obtenção dos 5-metoxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (97a), 6-metoxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (97b) e 7-metoxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (97c) envolve uma reação de aza-arilação de Heck catalisada por paládio na presença de carbonato de prata e acetona entre o N-tosil-o-iodoanilina (55b) e dihidronaftalenos substituídos (100a, 100b, e 100c), preparados previamente a partir de tetralonas comerciais (84a, 84b, 84c). Os compostos 5-hidroxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (98a), 6-hidroxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (98b) e o 7-hidroxi-11a-N-arilsulfonil-tetrahidro-5H--benzo[a]carbazol (98c) foram obtidos através da desproteção das metoxilas com BBr3 em rendimentos quantitativos. Todos os compostos foram avaliados quanto a ação anticâncer em linhagens de leucemia que apesentam o fenótipo MDR lucena e FEPS e em linhagem de leucemia K562 e nas linhagens de câncer de mama MCF-7, que expressa o receptor de estrogênio, e MDA-MD231.Dentre os compostos preparados, o composto 6-metoxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (97b) foi tão ativo quanto o LQB223 frente a ação antileucêmica nas linhagens K562, lucena e FEPS, entretanto foi mais eficaz que o LQB223 nas linhagens de MCF-7 (IC50 igual 5,93 mais ou menos 3,58 MiM) e MDA-MD231 (IC50 igual 8,29 mais ou menos 2,08 MiM), apresentando um nível baixo de toxicidade para as células sadias. Por outro lado, o composto 6-hidroxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (98b), apesar de ser muito ativo em linhagens de câncer mama, possui um alto nível de toxicidade para células sadias e composto 7-hidroxi-11a-N-arilsulfonil-tetrahidro-5H-benzo[a]carbazol (98c) foi eficaz em MDA-MD231 (IC50 igual 4,84) porém ainda não foi avaliado quanto a toxicidade em células sadias. Os dados sugerem que os compostos oxigenados 97b e 98c direciona a ação para o câncer de mama. / [en] This work describes the synthesis and characterization of the 11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazoles analogous to LQB223, a previously synthesized compound by our research group that has anti-cancer and antileishmanial activity in vitro and antimalarial activity in vitro and in vivo. The key step of the reaction for obtaining the 5-methoxy-11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazole (97a), 6-methoxy-11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazole (97b) and 7-methoxy-11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazole (97c) is the palladium catalyzed Heck aza-arylation reaction in the presence of silver carbonate and acetone from N-tosyl-o-iodoaniline (55b) and substituted dihydronaphthalenes (100a, 100b and 100c), previously prepared from commercial tetralones (84a, 84b and 84c). The compounds 5-hydroxy-11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazole (98a), 6-hydroxy-11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazole (98b) and 7-hydroxy-11a-N-arylsulfonil-tetrahydro-5H-benzo[a]carbazole (98c) were obtained by deprotection with BBr3 in yields quantitative. All compounds were evaluated for anticancer activity in K562, FEPS and Lucena leukemia cell lines, which exhibit the MDR phenotype, and in breast cancer cell lines MCF-7, which expresses the estrogen receptor, and MDA-MD231.Among the compounds prepared, the compound 97b is as active as LQB223 for the antileukemic activity on K562 lines, and Lucena FEPs, however it is more effective than the LQB223 in MCF-7 (IC50 equal 5.93 plus/minus 3.58 MiM) and MDA-MD231 (IC50 equal 8.29 plus/minus 2.08 uM) breast cancer lines, with low level of toxicity to healthy cells. The compound 98b presents similar activity to 97b but is toxic. The compound 98c is effective in MDA-MD231 (IC50 equal 4,84) but, level of toxicity to healthy cells was not test yet. The reports suggest that the oxygenation pattern in the 3 position directs to the anticancer activity to the breast cancer lines.

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