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REDOX IMAGING OF THE p53-DEPENDENT MITOCHONDRIAL REDOX STATE IN COLON CANCER EX VIVO.

Xu HN, Feng M, Moon L, Dolloff N, El-Deiry W, Li LZ - J Innov Opt Health Sci (2013)

Bottom Line: Nor has how p53 regulates mitochondrial respiration been measured at (deep) tissue level, presumably due to the unavailability of the technology that has sufficient spatial resolution and tissue penetration depth.The present work is the first to reveal at the submillimeter scale the intratumor heterogeneity pattern of the mitochondrial redox state in colon cancer and the first to indicate that at tissue level the mitochondrial redox state is p53 dependent.The findings should assist in our understanding on colon cancer pathology and developing new imaging biomarkers for clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA ; Britton Chance Laboratory of Redox Imaging, Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.

ABSTRACT

The mitochondrial redox state and its heterogeneity of colon cancer at tissue level have not been previously reported. Nor has how p53 regulates mitochondrial respiration been measured at (deep) tissue level, presumably due to the unavailability of the technology that has sufficient spatial resolution and tissue penetration depth. Our prior work demonstrated that the mitochondrial redox state and its intratumor heterogeneity is associated with cancer aggressiveness in human melanoma and breast cancer in mouse models, with the more metastatic tumors exhibiting localized regions of more oxidized redox state. Using the Chance redox scanner with an in-plane spatial resolution of 200 μm, we imaged the mitochondrial redox state of the wild-type p53 colon tumors (HCT116 p53 wt) and the p53-deleted colon tumors (HCT116 p53(-/-)) by collecting the fluorescence signals of nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins [Fp, including flavin adenine dinucleotide (FAD)] from the mouse xenografts snap-frozen at low temperature. Our results show that: (1) both tumor lines have significant degree of intratumor heterogeneity of the redox state, typically exhibiting a distinct bi-modal distribution that either correlates with the spatial core-rim pattern or the "hot/cold" oxidation-reduction patches; (2) the p53(-/-) group is significantly more heterogeneous in the mitochondrial redox state and has a more oxidized tumor core compared to the p53 wt group when the tumor sizes of the two groups are matched; (3) the tumor size dependence of the redox indices (such as Fp and Fp redox ratio) is significant in the p53(-/-) group with the larger ones being more oxidized and more heterogeneous in their redox state, particularly more oxidized in the tumor central regions; (4) the H&E staining images of tumor sections grossly correlate with the redox images. The present work is the first to reveal at the submillimeter scale the intratumor heterogeneity pattern of the mitochondrial redox state in colon cancer and the first to indicate that at tissue level the mitochondrial redox state is p53 dependent. The findings should assist in our understanding on colon cancer pathology and developing new imaging biomarkers for clinical applications.

No MeSH data available.


Related in: MedlinePlus

Tumor growth curve.
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Figure 1: Tumor growth curve.

Mentions: As a tumor suppressor gene, p53 inhibits the growth rate of HCT116 tumors, which we confirmed. After inoculation, about 60% mice grew p53 wt tumors and all mice grew p53−/− tumors. Figure 1 is the growth curve of a batch of mouse xenografts. For the same batch, the p53−/− tumors reached an average size 1260 × 550 mm3 (N = 7), over three times the average size of p53 wt group (364 ± 330 mm3, N = 3) 32 days after inoculation (p = 0.02). That the p53−/− group grows significantly faster than the p53 wt group is consistent with the literature.13 Because the p53 deletion group grew faster than the p53 wt group, we divided the p53−/− group into two subgroups: p53−/−small (N = 3, vol = 760 ± 284 mm3) and p53−/−large (N = 4, vol = 1634 ± 339 mm3). The tumor size of p53−/−small is significantly smaller than that of the p53−/−large as confirmed by the t-test (p = 0.015). The tumor size of the p53 wt group was matched up with the p53−/−small group (p = 0.19).


REDOX IMAGING OF THE p53-DEPENDENT MITOCHONDRIAL REDOX STATE IN COLON CANCER EX VIVO.

Xu HN, Feng M, Moon L, Dolloff N, El-Deiry W, Li LZ - J Innov Opt Health Sci (2013)

Tumor growth curve.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508871&req=5

Figure 1: Tumor growth curve.
Mentions: As a tumor suppressor gene, p53 inhibits the growth rate of HCT116 tumors, which we confirmed. After inoculation, about 60% mice grew p53 wt tumors and all mice grew p53−/− tumors. Figure 1 is the growth curve of a batch of mouse xenografts. For the same batch, the p53−/− tumors reached an average size 1260 × 550 mm3 (N = 7), over three times the average size of p53 wt group (364 ± 330 mm3, N = 3) 32 days after inoculation (p = 0.02). That the p53−/− group grows significantly faster than the p53 wt group is consistent with the literature.13 Because the p53 deletion group grew faster than the p53 wt group, we divided the p53−/− group into two subgroups: p53−/−small (N = 3, vol = 760 ± 284 mm3) and p53−/−large (N = 4, vol = 1634 ± 339 mm3). The tumor size of p53−/−small is significantly smaller than that of the p53−/−large as confirmed by the t-test (p = 0.015). The tumor size of the p53 wt group was matched up with the p53−/−small group (p = 0.19).

Bottom Line: Nor has how p53 regulates mitochondrial respiration been measured at (deep) tissue level, presumably due to the unavailability of the technology that has sufficient spatial resolution and tissue penetration depth.The present work is the first to reveal at the submillimeter scale the intratumor heterogeneity pattern of the mitochondrial redox state in colon cancer and the first to indicate that at tissue level the mitochondrial redox state is p53 dependent.The findings should assist in our understanding on colon cancer pathology and developing new imaging biomarkers for clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA ; Britton Chance Laboratory of Redox Imaging, Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.

ABSTRACT

The mitochondrial redox state and its heterogeneity of colon cancer at tissue level have not been previously reported. Nor has how p53 regulates mitochondrial respiration been measured at (deep) tissue level, presumably due to the unavailability of the technology that has sufficient spatial resolution and tissue penetration depth. Our prior work demonstrated that the mitochondrial redox state and its intratumor heterogeneity is associated with cancer aggressiveness in human melanoma and breast cancer in mouse models, with the more metastatic tumors exhibiting localized regions of more oxidized redox state. Using the Chance redox scanner with an in-plane spatial resolution of 200 μm, we imaged the mitochondrial redox state of the wild-type p53 colon tumors (HCT116 p53 wt) and the p53-deleted colon tumors (HCT116 p53(-/-)) by collecting the fluorescence signals of nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins [Fp, including flavin adenine dinucleotide (FAD)] from the mouse xenografts snap-frozen at low temperature. Our results show that: (1) both tumor lines have significant degree of intratumor heterogeneity of the redox state, typically exhibiting a distinct bi-modal distribution that either correlates with the spatial core-rim pattern or the "hot/cold" oxidation-reduction patches; (2) the p53(-/-) group is significantly more heterogeneous in the mitochondrial redox state and has a more oxidized tumor core compared to the p53 wt group when the tumor sizes of the two groups are matched; (3) the tumor size dependence of the redox indices (such as Fp and Fp redox ratio) is significant in the p53(-/-) group with the larger ones being more oxidized and more heterogeneous in their redox state, particularly more oxidized in the tumor central regions; (4) the H&E staining images of tumor sections grossly correlate with the redox images. The present work is the first to reveal at the submillimeter scale the intratumor heterogeneity pattern of the mitochondrial redox state in colon cancer and the first to indicate that at tissue level the mitochondrial redox state is p53 dependent. The findings should assist in our understanding on colon cancer pathology and developing new imaging biomarkers for clinical applications.

No MeSH data available.


Related in: MedlinePlus