Abstract P6-04-03: Transcriptome profiling reveals enrichment of luminal feature in aged basal cell population in murine mammary gland

Aging is the number one risk factor for breast cancer development. Increasing evidence suggests the potential of mammary stem cells (MaSCs) and their progenitors to generate certain types of breast cancers through neoplastic transformation. Our previous study has shown increased percentage of MaSC-enriched basal cell population (Lin-CD49fhighCD24med) and increased MaSC frequency during aging in murine models. On the other hand, a recent study from another group showed an increased frequency of CD49fhigh cells in the human luminal population (CD227+) during aging, indicating possible aberrant expression of CD49f in the aged luminal cells. However, how these age-related luminal cells with basal markers are generated and how they contribute to potential breast cancer development remains unknown. Here we apply bioinformatics analysis on Next Generation Whole Transcriptome Sequencing data of MaSC-enriched basal cell population (Lin-CD49fhighCD24med) and luminal progenitor-enriched cell population (Lin-CD49flowCD24high) of both young (4 to 6 months) and old (26 to 31 months) mouse mammary gland to test the hypothesis that age-associated increase of basal cell population and MaSCs may be due to the gain of basal cell markers and features by luminal cells. By Gene Set Enrichment Analysis (GSEA) we found a significant loss of basal cell and basal mammosphere signatures and a significant enrichment of luminal cell and luminal mammosphere signature in the old basal cell population and mammospheres in comparison with the young basal cell population and mammospheres. The core enrichment luminal genes from GSEA are able to cluster the old MaSC-enriched basal cell population as well as mammospheres closer to the cluster of luminal population than to the young basal population. These analyses indicate that aging may be associated with an expansion of aberrant MaSCs with both basal and luminal markers in mice, which may be the precursors of certain types of breast cancer. We are now studying the potential function of the basal-like luminal cells in the aged basal population.

Citation Format: Gu X, Gao H, Wu A, Bandyopadhyay A, Dong Q, Sun L-Z. Transcriptome profiling reveals enrichment of luminal feature in aged basal cell population in murine mammary gland. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-04-03.

Investigation of the extraordinary null reconstruction phenomenon in polarization volume hologram

Polarization holography is the superposition of differently polarized beams. Due to its ability to record the polarization states, some extraordinary optical phenomena were found in the polarization holography. For example, the recently reported null-reconstruction phenomenon in polarization volume hologram is odd for the conventional holography which only records the amplitude and phase. In this paper, we perform a thorough investigation of the null reconstruction of polarization hologram recorded by orthogonal circularly polarized waves. To explore the mechanism behind this phenomenon, an interferometry was built to measure the phase difference between the same polarized components within the reconstructed wave. The phase difference of π was secured in our experiment, indicating a destructive interfering effect, which nicely explains the extraordinary null reconstruction observed in the polarization hologram.

A rabbit model of antegrade selective cerebral perfusion with cardioplegic arrest

OBJECTIVE

Due to the weak ascending aorta, it is extremely challenging to establish an anterograde selective cerebral perfusion (ASCP) model in rabbits, especially when cardioplegic arrest is required. Herein, the aim of this study was to establish a rabbit ASCP model with cardiac arrest being easily performed and being similar to the clinical scenario.

MATERIALS AND METHODS

Twenty-two adult New Zealand white rabbits were selected for ASCP model establishment and another 22 rabbits were utilized for blood donation. The cardiopulmonary bypass (CPB) circuit consisted of a roller pump, a membrane oxygenator, a heat-cooler system and a blood reservoir, which were connected by silicone tubing. The total priming volume of the circuit was 70 ml. Cannulations on the right and left subclavian arteries were used for arterial inflow and cardioplegia perfusion, respectively. Venous drainage was conducted through the right atrial appendage. ASCP was initiated by clamping the innominate artery; the flow rate was maintained 10 ml/kg/minute and sustained for 60 minutes. After 120 minutes of reperfusion, the rabbits were sacrificed. The mean arterial pressure, heart rate, electrocardiogram and urine output were monitored. Arterial blood samples were analyzed at the following time points: after anesthesia, immediately after CPB, after aorta cross-clamping and cardioplegia perfusion, 5 min after the re-opening of the aorta and at CPB termination.

RESULTS

ASCP modeling was performed successfully on 18 rabbits and 4 rabbits unsuccessfully. Vital signs and blood gas indictors changed in an acceptable range throughout the experiments. One rabbit had ventricular fibrillation after re-opening of the ascending aorta. Obvious hemodilution occurred after the perfusion of cardioplegia, but the hematocrit improved after CPB termination.

CONCLUSION

By using cannulation of the subclavian artery rather than the aorta and with a low priming volume, we established a modified rabbit model of ASCP with cardioplegic arrest. The model has excellent repeatability and operability, which is similar to the clinic process and is suitable for the study of cerebral, cardiac and renal protection.

Activation of p38 MAPK in the rostral ventromedial medulla by visceral noxious inputs transmitted via the dorsal columns may contribute to pelvic organ cross-sensitization in rats with endometriosis

Whether visceral organ cross-sensitization is involved in endometriosis-associated pain remains elusive. Previous studies have shown that visceral noxious stimuli may trigger a cascade of signal transductions in the rostral ventromedial medulla (RVM) via the spinal dorsal column (DC) pathway and the RVM plays a critical role in the descending control of visceral nociception. In the current study, we hypothesized that the p38 mitogen-activated protein kinase (MAPK) activation in the RVM by noxious visceral inputs from ectopic growths via the DC was involved in the development of pelvic organ cross-sensitization in established endometriosis. A rat model of experimental endometriosis was established. To examine ectopic growths-to-colon cross-sensitization, graded colorectal distention (CRD) was performed and abdominal withdrawal reflex (AWR) scores were recorded in female rats at 8weeks after the uterine or fat (control) auto-transplantation. Western blot study was carried out to examine the phosphorylated form and the total level of p38 MAPK protein in the RVM. Our results showed that lesions of bilateral DCs immediately following uterine or fat auto-transplantation in female rats significantly attenuated the later development of ectopic growths-to-colon cross-sensitization and the increased p38 MAPK activation in the RVM, as compared to sham DC lesions. Furthermore, intra-RVM microinjection of a p38 MAPK inhibitor (SB 203580), but not vehicle, in female rats with established endometriosis significantly attenuated ectopic growths-to-colon cross-sensitization and the increased activation of p38 MAPK in the RVM. These findings suggest that the noxious inputs from ectopic growths may activate p38 MAPK in the RVM via the DC, which may contribute to the development of ectopic growths-to-colon cross-sensitization in established endometriosis.