Cardiac Remodeling in the Absence of Cardiac Contractile Dysfunction Is Sufficient to Promote Cancer Progression

Figures

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  Figure 1. Phenylephrine infusion promotes tumor growth. (A) Schematic experimental timeline. Polyoma middle T (PyMT) cells were injected four weeks after PE-infusion (n = 4) and compared to control mice (n = 4). (B) Mice received orthotopic implants in the mammary fat pad with PyMT cells (105 cells per mouse). Tumor volume was monitored over time with the following formula: width2 × length × 0.5. (C) Tumor weight at the endpoint. Data are presented as mean ± SEM and analyzed via Student’s t-test. * p < 0.05. *** p < 0.001.

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  Figure 2. Cardiac remodeling hallmarks following PE infusion. (A) Ventricle weight (VW) to body weight (BW) ratio at the endpoint. (B) The mRNA levels of hypertrophic markers ANP and BNP were determined via qPCR, normalized with GAPDH. Data are presented as mean ± SEM relative expression compared to control hearts, determined as 1. (C) Representative images and quantification of heart sections (n = 4, at least 5 fields per mouse) stained using Masson’s trichrome. Scale bar: 500 and 50 µm. (D,E) Heart mRNA levels of fibrosis markers TGFβ3, collagen 1α and Acta2 (D) and inflammation markers IL-1β, IL-6 and F4-80 (E) were determined via qRT-PCR, normalized with GAPDH. (F) Echocardiography was performed one day prior to sacrifice. Fractional shortening (FS) was assessed according to the formula: FS (%) = ((LVDd − LVDs)/LVDd)). Data are presented as mean ± SEM relative expression compared to control hearts, determined as 1. Data were analyzed via multiple Student’s t-tests. * p <0.05. ** p <0.01.

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  Figure 3. PE infusion increases cancer cell proliferation. (A) Representative image of PyMT tumor sections of control and PE-infused mice stained with anti-Ki67 (proliferating cells; green) and DAPI (nuclei; blue). Scale bar: 50 µm. (B) Quantification of the number of proliferating cells in tumor section field (n = 4, at least 5 fields per each mouse). (C) PyMT cells were cultured for 48 h in the absence or presence of 10% FBS either with or without PE at 10 μg/mL, and mouse blood serum drawn from either control or PE-infused mice. Proliferation was measured using a Luminescent Cell Viability Assay using serum from at least three mice per group. Data are presented as mean ± SEM and were analyzed using either Student’s t-test (B) or one-way repeated-measures ANOVA, followed by Tukey posttests (C). * p < 0.05. *** p < 0.001.

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  Figure 4. The tumor promotion phenotype is mediated by secreted factors, expressed in either the heart or the tumor. (A) Serum levels of periostin, fibronectin and CTGF were determined via ELISA. (B,C) mRNA levels from either the heart (B) or tumor (C) of the indicated genes were measured by means of qRT-PCR, normalized with GAPDH (heart) or Hsp90 (tumor) house-keeping genes. Data are presented as relative expression compared with control, determined as 1. Data are presented as mean ± SEM and were analyzed via multiple Student’s t-tests. * p < 0.05. ** p < 0.01. *** p < 0.001.

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  Figure 5. Cardiac remodeling in the absence of cardiac contractile dysfunction is sufficient for tumor promotion. The PE-infusion model. Cancer cells were implanted four weeks after the implantation of PE-infusing pumps. Cardiac remodeling occurred prior to tumor implantation with no apparent cardiac contractile dysfunction, although tumor progression was readily observed. Cardiac (orange and green dots) and tumor-secreted factors (yellow dots) are responsible for tumor growth in a paracrine and autocrine fashion.