Bioluminescent human breast cancer cell lines that permit rapid and sensitive in vivo detection of mammary tumors and multiple metastases in immune deficient mice

INTRODUCTION: Our goal was to generate xenograft mouse models of human breast cancer based on luciferase-expressing MDA-MB-231 tumor cells that would provide rapid mammary tumor growth; produce metastasis to clinically relevant tissues such as lymph nodes, lung, and bone; and permit sensitive in vivo detection of both primary and secondary tumor sites by bioluminescent imaging. METHOD: Two clonal cell sublines of human MDA-MB-231 cells that stably expressed firefly luciferase were isolated following transfection of the parental cells with luciferase cDNA. Each subline was passaged once or twice in vivo to enhance primary tumor growth and to increase metastasis. The resulting luciferase-expressing D3H1 and D3H2LN cells were analyzed for long-term bioluminescent stability, primary tumor growth, and distal metastasis to lymph nodes, lungs, bone and soft tissues by bioluminescent imaging. Cells were injected into the mammary fat pad of nude and nude-beige mice or were delivered systemically via intracardiac injection. Metastasis was also evaluated by ex vivo imaging and histologic analysis postmortem. RESULTS: The D3H1 and D3H2LN cell lines exhibited long-term stable luciferase expression for up to 4–6 months of accumulative tumor growth time in vivo. Bioluminescent imaging quantified primary mammary fat pad tumor development and detected early spontaneous lymph node metastasis in vivo. Increased frequency of spontaneous lymph node metastasis was observed with D3H2LN tumors as compared with D3H1 tumors. With postmortem ex vivo imaging, we detected additional lung micrometastasis in mice with D3H2LN mammary tumors. Subsequent histologic evaluation of tissue sections from lymph nodes and lung lobes confirmed spontaneous tumor metastasis at these sites. Following intracardiac injection of the MDA-MB-231-luc tumor cells, early metastasis to skeletal tissues, lymph nodes, brain and various visceral organs was detected. Weekly in vivo imaging data permitted longitudinal analysis of metastasis at multiple sites simultaneously. Ex vivo imaging data from sampled tissues verified both skeletal and multiple soft tissue tumor metastasis. CONCLUSION: This study characterized two new bioluminescent MDA-MB-231-luc human breast carcinoma cell lines with enhanced tumor growth and widespread metastasis in mice. Their application to current xenograft models of breast cancer offers rapid and highly sensitive detection options for preclinical assessment of anticancer therapies in vivo

Caracterização de patótipos de Colletotrichum lindemuthianum que ocorrem em algumas regiões produtoras de feijoeiro comum.

A antracnose do feijoeiro comum incitada por Colletotrichum lindemuthianum apresenta ampla distribuição no Brasil, especialmente nas regiões sul e sudeste e em áreas serranas onde as temperaturas moderadas favorecem o seu desenvolvimento. No presente estudo foram testados 118 isolados e determinados 25 patótipos pertencentes aos grupos Alfa, Deita, Gama, Mexicano I, Mexicano II e Brasileiro I. O grupo Alfa apresentou a maior freqüência de isolados (53,39%) e, dentro dele, os isolados compatíveis com o gene de resistência ARE (patótipos 73, 89 e 585) representaram 68,25% do grupo e 36,44% do número total de isolamentos. A seguir, apresentou-se o grupo Delta com 27,97% do total dos isolados testados, sendo que apenas 3,39% (patótipos 79 e 95) apresentou reação compatível com o gene ARE. Os patótipos 453 (Brasileiro I), 343 (Delta) e 339 (Mexicano Il) induziram reação de compatibilidade com a cultivar TO (gene Mex. 2), enquanto que o patótipo 585 (Alfa) apresentou reação de compatibilidade com a cultivar TU (gene Mex. 3). Os patótipos 65 e 87 apresentaram a maior distribuição geográfica, enquanto que os Estados do Espírito Santo, Paraná, Goiás e Bahia, os maiores números de patótipos. A identificação de patótipos que induziram reações compatíveis com as cultivares TO e TU reveste-se da maior importância, já que os genes de resistência Mex. 2 e Mex. 3 têm sido amplamente utilizados como fontes de resistência na maioria dos programas de melhoramento no país