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A New Role for Hypoxia in Tumor Progression

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1 A New Role for Hypoxia in Tumor Progression
Arnaud Coquelle, Franck Toledo, Sabine Stern, Anne Bieth, Michelle Debatisse  Molecular Cell  Volume 2, Issue 2, Pages (August 1998) DOI: /S (00)

2 Figure 1 Evolution of DMs Bearing the mdr1 Gene
(A) Cell with DMs in CN-containing medium. (A1) DAPI staining, arrows point to some DMs. (A2) FISH with an mdr1 probe (yellow) and a probe for P3C4, a specific marker of the telomeric part of chromosome 1q (red); arrowhead, normal mdr1 copy. DMs are homogeneous in size and bear one or few mdr1 copies. The presence of the red marker on both homologs indicates that no rearrangement of the telomeric part of the 1q chromosomes occurred during the amplification process. (B1 and B2) Heterogeneization of DMs in AMD-containing medium. (B1) DAPI staining, arrows point to DMs of various sizes, from small DMs similar to those shown in (A) to very large ones. (B2) FISH with an mdr1 probe (yellow), showing that the size of DMs correlates with their mdr1 gene copy number. Molecular Cell 1998 2, DOI: ( /S (00) )

3 Figure 2 Extrachromosomal Amplification of Nonsyntenic Sequences in Doubly Resistant Cells (A) Doubly resistant cell at early stages of ampd2 amplification (see text for details). (A1) DAPI staining. (A2) FISH with probes for mdr1 (yellow) and ampd2 (red) showing that most DMs bear only ampd2 or mdr1 genes. Arrowheads and arrows, examples of DMs bearing only mdr1 or ampd2 gene, respectively. (B) Doubly resistant cells following induction of fragile sites. (B1) DAPI staining. (B2) Only the yellow fluorescence is visualized (mdr1). (B3) Only the red fluorescence is visualized (ampd2). (B4) Double color FISH; most DMs bear both ampd2 and mdr1 genes. Molecular Cell 1998 2, DOI: ( /S (00) )

4 Figure 3 In Doubly Resistant Cells, Reintegration of DMs Generates HSRs Containing Nonsyntenic Regions (A) Reintegration of DMs bearing mdr1 genes within the broken chromosome 1q undergoing ampd2 gene amplification through BFB cycles. FISH with probes for mdr1 (yellow) and ampd2 (red). Coamplification of the two genes on chromosome 1q is shown. (A1) Only the yellow fluorescence is visualized. (A2) Only the red fluorescence is visualized. (A3) Double color FISH; amplified copies of mdr1 and ampd2 genes are organized with successive orders of symmetry, as expected from the operation of BFB cycles (Toledo et al. 1992). (B) Reintegration of DMs bearing mdr1 and ampd2 genes generates complex HSR at ectopic location. FISH with probes for ampd2 (yellow) and mdr1 (red). Both mdr1 and ampd2 genes are located within the same HSR on chromosome 1p; arrowhead, normal mdr1 gene; arrows, normal ampd2 genes. (C) Repeated induction of fragile sites generates a large marker chromosome containing both mdr1 and ampd2 genes. FISH with probes for mdr1 (yellow) and ampd2 (red). Arrow points to the normal ampd2 gene on a chromosome 1. Compare the size of this chromosome to the size of the marker bearing the amplified copies. Molecular Cell 1998 2, DOI: ( /S (00) )

5 Figure 4 DMs in a Human Gastric Carcinoma Cell Line
(A) Typical Snu 16 cell. (1) DAPI staining. (2) Double color FISH with probes for the c-myc (yellow) and k-sam/fgfr2 (red) oncogenes. The cell contains DMs carrying only copies of c-myc (long arrows), DMs carrying only copies of k-sam/fgfr2 (short arrows), or DMs carrying copies of both oncogenes (arrowheads). Molecular Cell 1998 2, DOI: ( /S (00) )


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