Abstract PD2-04: FOXA1 induces a pro-metastatic secretome through ER-dependent and independent transcriptional reprogramming in endocrine-resistant breast cancer

Background: Metastasis in ER-positive (+) breast cancer (BC) occurring years to decades after initial diagnosis presents a daunting challenge for clinical care and preclinical research due to limited known key players and experimental models. FOXA1 is a pioneer factor for ER-chromatin binding and function, and is highly expressed in ER+ BC metastases, yet the underlying mechanism is unclear. Tumor-secreted proteins play a crucial role in the reciprocal interplay between cancer cells and host microenvironmental factors at both primary and secondary sites. We hypothesized that high FOXA1 provokes an ER-dependent transcriptional program that includes a unique pro-tumorigenic secretome essential for promoting ER+ BC metastasis. Methods: A lentiviral doxycycline (Dox)-inducible FOXA1 overexpression vector and a dual luciferase/GFP (LG) tracking vector were integrated to construct a stable MCF7-LG/FOXA1 cell model. Ovariectomized nude mice bearing MCF7-LG/FOXA1 xenografts in the presence of exogenous estrogen (E2) were randomized to ± Dox, each with continued E2, E2 deprivation (ED), or tamoxifen (Tam). Survival surgery removing the therapy-naïve (E2 arm) and relapsed (ED/Tam arms) tumors was performed when tumors reached ∼1000 mm3. All mice then received ED/Tam 'adjuvant' therapy, with longitudinal luminescence imaging to monitor local/distant recurrences. Mice were or will be euthanized at the ethical end-point. Integrative bioinformatics was performed using RNA-seq and FOXA1/ER ChIP-seq data from our preclinical models to identify secretome targets for functional intervention. Times to tumor regression (TTR) and progression (TTP) were defined by when the tumor reached half or twice the volume at randomization. Results: Median (m) TTR was achieved in ED (31/34 days, -/+Dox, P = 0.184) but not in Tam groups — Tam delayed tumor growth but failed to prevent progression in all mice with mTTP of 94/93 days (-/+Dox, P = 0.517). Despite no difference in mTTP at Tam-/+Dox, a quarter of +Dox tumors (3/12) had volume doubled by day 11. No metastases were observed by imaging in any of the mice before surgery ('neoadjuvant' setting). Local relapse and lymph-node/lung metastases were detected after surgery ('adjuvant' setting). At day 90 in the adjuvant Tam group with previously relapsed tumors, +Dox mice succumbed to metastasis more often than -Dox mice (7/8 vs. 3/10, P = 0.023). Compared to the adjuvant Tam+Dox mice with previous therapy-naïve tumors, the Tam+Dox with previously relapsed tumors showed higher distant metastasis rate (7/8 vs. 5/14, P = 0.026). Analysis of the ED setting is pending due to late recurrence. Data integration and functional study revealed a set of cytokines, growth factors, and extracellular matrix components (including IL-8, CTGF, and LOX), regulated by FOXA1 often in conjunction with ER, that are highly involved in FOXA1-induced metastasis. Global secretome profiling by mass spectrometry and target validation are ongoing. Conclusions: FOXA1 overexpression increases metastatic potential in ER+ BC. We established a pertinent metastatic xenograft mouse model to characterize a pro-metastatic secretome with diagnostic and therapeutic potential for treating metastatic ER+ BC.

Citation Format: Fu X, Pereira R, Zhao D, Jung SY, Jeselsohn R, Creighton CJ, Shea M, Nardone A, Angelis CD, Tsimelzon A, Wang T, Gutierrez C, Huang S, Edwards DP, Rimawi MF, Hilsenbeck SG, Brown M, Chen K, Osborne CK, Schiff R. FOXA1 induces a pro-metastatic secretome through ER-dependent and independent transcriptional reprogramming in endocrine-resistant breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD2-04.

Tropospheric Emissions: Monitoring of Pollution (TEMPO)

TEMPO was selected in 2012 by NASA as the first Earth Venture Instrument, for launch between 2018 and 2021. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO observes from Mexico City, Cuba, and the Bahamas to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution (~2.1 km N/S×4.4 km E/W at 36.5°N, 100°W). TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry, as well as contributing to carbon cycle knowledge. Measurements are made hourly from geostationary (GEO) orbit, to capture the high variability present in the diurnal cycle of emissions and chemistry that are unobservable from current low-Earth orbit (LEO) satellites that measure once per day. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a commercial GEO host spacecraft to provide a modest cost mission that measures the spectra required to retrieve ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (H2CO), glyoxal (C2H2O2), bromine monoxide (BrO), IO (iodine monoxide),water vapor, aerosols, cloud parameters, ultraviolet radiation, and foliage properties. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides these near-real-time air quality products that will be made publicly available. TEMPO will launch at a prime time to be the North American component of the global geostationary constellation of pollution monitoring together with the European Sentinel-4 (S4) and Korean Geostationary Environment Monitoring Spectrometer (GEMS) instruments.

Does logging and forest conversion to oil palm agriculture alter functional diversity in a biodiversity hotspot?

Forests in Southeast Asia are rapidly being logged and converted to oil palm. These changes in land-use are known to affect species diversity but consequences for the functional diversity of species assemblages are poorly understood. Environmental filtering of species with similar traits could lead to disproportionate reductions in trait diversity in degraded habitats. Here, we focus on dung beetles, which play a key role in ecosystem processes such as nutrient recycling and seed dispersal. We use morphological and behavioural traits to calculate a variety of functional diversity measures across a gradient of disturbance from primary forest through intensively logged forest to oil palm. Logging caused significant shifts in community composition but had very little effect on functional diversity, even after a repeated timber harvest. These data provide evidence for functional redundancy of dung beetles within primary forest and emphasize the high value of logged forests as refugia for biodiversity. In contrast, conversion of forest to oil palm greatly reduced taxonomic and functional diversity, with a marked decrease in the abundance of nocturnal foragers, a higher proportion of species with small body sizes and the complete loss of telecoprid species (dung-rollers), all indicating a decrease in the functional capacity of dung beetles within plantations. These changes also highlight the vulnerability of community functioning within logged forests in the event of further environmental degradation.

Rectovaginal fistula in Crohn's disease

PURPOSE

Crohn's disease is characterized by transmural bowel inflammation and a tendency to form fistulas with adjacent structures. Several different fistulas have been described: enterocutaneous, enteroenteric, enterovesical, enterovaginal, and perineal. Rectovaginal fistulas are difficult to treat despite multimodal therapy. This study was designed to review the current strategic options to best manage this condition.

METHODS

We reviewed the English-language literature from 1966 to 2006, using PUBMED, targeting Crohn's disease involving vagina using key words "rectovaginal fistula and CD," "anovaginal fistula and CD," "anovaginal fistula," and "rectovaginal fistula." We excluded the involvement of the vagina from a pouch after a proctectomy. A total of 776 articles were found; 206 articles were identified and judged as being relevant on the basis of title-related articles and links were reviewed. Fifty-three articles were selected after reading the abstract or full manuscript.

RESULTS

The management of rectovaginal fistula, representing 9 percent of all fistulas, remains a challenge in the setting of Crohn's disease. Medical treatments are not favorable with low rates of long-term symptomatic control and unacceptable high rates of recurrence. Several novel and new surgical techniques have been described, and rectal advancement flap, in selected patients, seems to have the most successful results.

CONCLUSIONS

The management of rectovaginal fistula of Crohn's origin should involve both gastroenterologists and coloproctologists, with the best surgical results being achieved in patients receiving optimum medical therapy. More focused studies targeting these patients with the use of combined medical and surgical therapy are necessary.

Following anterior resection for rectal cancer, defunctioning ileostomy closure may be significantly delayed by adjuvant chemotherapy: a retrospective study

OBJECTIVE

A temporary loop ileostomy is often created to minimize the impact of peritoneal sepsis from an anastomotic dehiscence following colo-anal or low colorectal anastomosis. These stomas are not without complications. Clinicians tend to advise patients that their loop ileostomy will be reversed within 6-12 weeks of formation. However, factors such as adjuvant chemotherapy may affect the timing of closure. The aim of this study was to review the time between formation and closure of loop ileostomies following total mesorectal excision in patients with rectal cancer.

METHOD

A retrospective study of 50 patients with loop ileostomies to defunction total mesorectal excisions for rectal cancer, between April 2002 and July 2005.

RESULTS

Of the 50 patients with defunctioning loop ileostomies, 24 received adjuvant chemo-radiotherapy, and 26 did not. There was a 28% morbidity. The overall median time from formation to closure was 142 days (35-575). Median time from formation to closure in those with adjuvant therapy was 197 days (35-575) and in those with no adjuvant therapy was 133 days (75-395). This was a significant delay (P = 0.049). Sixteen stomas were not closed to date.

CONCLUSION

Time between formation and closure of loop ileostomy following anterior resection of rectum is significantly delayed by adjuvant chemotherapy. Because of their high morbidity, defunctioning ileostomies should be closed as early as medically possible, especially if adjuvant chemotherapy is planned.

Long-term results show triple stapling facilitates safe low colorectal and coloanal anastomosis and is associated with low rates of local recurrence after anterior resection for rectal cancer

BACKGROUND

During low anterior resection (AR), placement of a staple line distal to an occlusion clamp is often difficult due to the confines of a narrow bony pelvis. This study reviewed the results of AR with a technique in which a linear staple line is fired below the tumour as an oncologically safe occlusion clamp.

METHODS

Between 1995 and 2000, a total of 174 patients were operated for rectal cancer, and 153 of these patients had AR. Triple stapling (TS) was used to place a line of staples that occluded the fully mobilised rectum below a tumour. After rectal washout, a further linear stapler was applied below the first, and the rectum was divided prior to a standard circular stapled anastomosis.

RESULTS

TS was performed in 127 (83%) of 153 patients undergoing AR, and 9 TS patients developed leaks (7%). In the whole series of 174 cases, 9 patients had local recurrence (5%), but the local recurrence rate for procedures classified as 'locally curative' was 2%.

CONCLUSIONS

Triple stapling reliably occludes the rectum allowing for distal rectal washout. It eliminates clamp slippage and faecal spillage and improves access to the distal rectum for low anastomoses.

The house advancement anoplasty for treatment of anal disorders

OBJECTIVES

Anal advancement flaps treat a variety of anal disorders. In recent years the "House" advancement flap has been used with good success, the term referring to the shape of the flap used. It is simple with few shortcomings. We reviewed a single centre's experience of this procedure.

METHODS

All patients who underwent a house advancement flap between 1996 and 2001 were identified. The case notes were examined and data collected on indication for surgery, complications, follow-up and outcome.

RESULTS

Thirteen consecutive patients were identified, mean age of 44 years. Indications for surgery were chronic anal fissure, fistulous disease and post surgical deformity or stenosis of the anal canal. Median follow-up was 37 months (25-84). In 9 patients the flaps healed within 4 weeks. In the remaining 4 patients the flaps healed by secondary intention over a median of 14 weeks (8-20). Postoperative complications occurred in 5 patients (3 donor site separation and 2 flap retraction). Two patients developed recurrence of their original disorder. Eleven patients have relief of pre-operative symptoms with fully healed flaps.

CONCLUSION

This procedure is simple, easy to construct and robust. It can be performed for a variety of anal disorders with satisfactory results and few complications and should be in every Coloproctologist's armamentarium.

The use of intra-operative endo-anal ultrasound in perianal disease

INTRODUCTION

Endoanal ultrasound (EAUS) has demonstrated high sensitivity and specificity for the structural imaging of anorectal pathology. This study prospectively assessed the impact of intra-operative EAUS on the surgical management of perianal disease.

METHODS

EAUS was performed prior to and after examination under anaesthesia (EUA) in a consecutive series of patients with perianal disease. The impact of EAUS on the surgery performed was identified.

RESULTS

Forty-three procedures have been performed in 38 patients (21 male, 17 female; mean age 42.7 years, range 6-76 years) over a three year period. Pathologies encountered were fistula-in-ano (42%), fissure-in-ano (26%), complicated perianal sepsis (16%) and carcinoma (5%). No specific abnormality was identified in 5 symptomatic patients (12%). Four patients with fissures had undergone previous sphincterotomy. In 22 cases (51.2%) the EAUS findings affected the surgical management (extent of muscle above a fistula 9 cases, extent of sphincterotomy 7 cases, site of sepsis identified 2 cases, exclusion of sepsis 2 cases, assessment of cancer resectability 1 case, biopsy of intersphincteric lesion 1 case).

CONCLUSION

Intra-operative EAUS accurately identifies perianal disease and influences the surgical procedure performed. While not essential, it is a useful adjunct especially in recurrent perianal sepsis, undiagnosed anorectal pain and anal fissure.

Management of the rectal stump after emergency sub-total colectomy: which surgical option is associated with the lowest morbidity?

OBJECTIVE

To identify the preferred surgical management of the rectal stump after emergency subtotal colectomy (ESC) for acute severe colitis by assessing the morbidity associated with each option.

PATIENTS AND METHODS

Consecutive patients undergoing ESC at a district general hospital between 1999 and 2004 were retrospectively audited for pathology, rectal stump complications and length of postoperative hospital stay (POS).

RESULTS

Thirty-seven ESCs were performed, 34 were undertaken for disease refractory to medical treatment, 2 for toxic mega colon and 1 for perforation. Thirty-four cases were for ulcerative colitis, 2 Crohn's colitis and 1 infective colitis. Twenty-seven had an intraperitoneal and 10 a subcutaneously placed closed rectal stump. The median POS for patients with a subcutaneously placed stump was shorter than for those with an intraperitoneal stump, 8 and 15 days, respectively (P = 0.04). Two patients had leakage from an intraperitoneal stump, prolonging POS (33 and 193 days). Three of the subcutaneous stumps leaked causing wound infection but not prolonging the POS (6, 7 and 16 days).

CONCLUSION

Avoiding a second stoma by closing the rectal stump after ESC has been confirmed as acceptable practice by studies over the last 15 years, reporting no overall increase in complications. The location of a closed rectal stump appears to influence the incidence of pelvic sepsis. The lowest pelvic sepsis rate is associated with subcutaneous placement; despite a higher wound infection rate this option appears to be associated with a lower total morbidity reflected in a shorter POS.

The validation of new aromatase monoclonal antibodies for immunohistochemistry--a correlation with biochemical activities in 46 cases of breast cancer

Intratumoral aromatase is a therapeutic target for the treatment of post-menopausal estrogen-dependent breast cancers. Therefore, reliable methods should be developed for routine application for the detection of intratumoral aromatase. Immunohistochemistry (IHC) is considered one of the most suitable methods in this regard. A multi-centre collaborative group has been established to generate and validate new aromatase monoclonal antibodies. We have selected two monoclonal antibodies, #677 against native aromatase protein and F2 against formalin-fixed protein for this purpose. With these two monoclonal antibodies 43 cases of invasive ductal carcinoma, which had been previously assayed for aromatase activity by product isolation methodology, were immunostained in three laboratories in UK, USA and Japan and independently evaluated by three pathologists (H.S., T.A. and S.G.S.). Staining of malignant epithelium, adipose tissue, normal/benign and stromal compartments of the tumors were assessed by estimating the proportion of positive staining cells and the relative intensity of staining in this fashion. Immunoreactivity could be detected in each component of the tissue specimens but a significant positive correlation with biochemical activity was detected only in malignant epithelium stained with 677 not in other components with #677 and not in any of the components. Staining using F2 as a primary antibody did not produce a positive correlation in any components with aromatase activity. These results suggest that we now have a monoclonal antibody against aromatase (#677) which may be used to stain archival materials. A methodology and scoring system is recommended whereby staining significantly correlates with aromatase activity of the resected tissue specimens of breast cancer.

Validation of new aromatase monoclonal antibodies for immunohistochemistry: progress report

Intratumoral aromatase is a potential therapeutic target for the treatment of postmenopausal estrogen-dependent breast cancers. Therefore, reliable methods should be developed for routine application for the detection of intratumoral aromatase. A multi-center collaborative group has been established to generate and validate new aromatase monoclonal antibodies (MAbs). A recombinant GST-aromatase fusion protein was expressed in baculovirus and the purified protein was used for immunization of mice either as a native or formalin-fixed antigen. Hybridomas were generated using standard techniques and screened biochemically prior to immunohistochemistry (IHC) evaluation in human placenta, ovary and breast cancer tissues. Twenty-three MAbs selected by biochemical assays were further evaluated by IHC of paraffin-embedded tissue sections including normal ovary, and placenta, and a small series of 10 breast carcinomas. Of the 23 MAbs, 2 (clones 677 and F2) were determined to specifically stain cell types known to express aromatase in normal tissues. In breast carcinomas staining of malignant epithelium, adipose tissue, normal/benign and stromal compartments was detected. IHC was performed and independently evaluated by three pathologists (HS, TJA and SGS), each using the same evaluation criteria for staining intensity and proportion of immunopositive cells. With these two MAbs, interpathologist and intralaboratory variations were minimal in comparison with differences which could be detected between tissue specimens and antibodies.

Long-term results of polyp clearance by intraoperative enteroscopy in the Peutz-Jeghers syndrome

PURPOSE

Enteroscopy during laparotomy for Peutz-Jeghers syndrome was introduced in our unit in 1987. Its aim is to achieve more complete polyp clearance and thereby reduce the number of subsequent laparotomies for small intestinal polyps.

METHODS

All patients with Peutz-Jeghers syndrome who had undergone intraoperative enteroscopy since its introduction into our unit in 1987 were identified. The numbers of polyps identified by palpation and transillumination and by enteroscopy were recorded. The timing of, indications for, and findings of all subsequent laparotomies were analyzed and compared with data from our unit before the introduction of intraoperative enteroscopy.

RESULTS

Twenty-five patients (14 females) were studied. Enteroscopy identified 350 (median 12, range 0-35) polyps not detected by palpation and transillumination. All impalpable polyps were removed endoscopically by snare or biopsy. The median follow-up was 53 (interquartile range, 13-133) months. Six patients have had an additional laparotomy (1 urgent relaparotomy for small-bowel perforation after endoscopic polypectomy, 4 polypectomies, and 1 adhesion obstruction). No patient has required operative polypectomy within 4 years of polyp clearance by intraoperative enteroscopy, compared with registry data of 4 (17 percent) of 23 patients who had more than 1 laparotomy within 1 year.

CONCLUSION

Intraoperative enteroscopy for Peutz-Jeghers syndrome improves polyp clearance without the need for additional enterotomies and may help to reduce the frequency of laparotomies.

The medical and surgical management of chronic anal fissure

Major advances in our understanding of the mechanisms involved in chronic anal fissure have allowed the introduction of many new medical therapies for this condition. The literature about current treatment modalities licensed for anal fissure and those novel therapies still under evaluation has been reviewed. These new treatments are examined in the context of traditional surgical management of the disease and a future treatment algorithm suggested.

Retroperitoneal gas gangrene complicating elective inguinal hernia repair

Gas gangrene is a well recognised complication of contaminated military wounds. A case of Clostridial myonecrosis following elective inguinal hernia repair is described. The pathology, clinical features and management of this life-threatening condition are reviewed.

Progesterone receptor contains a proline-rich motif that directly interacts with SH3 domains and activates c-Src family tyrosine kinases

Steroid hormones have rapid nongenomic effects on cell-signaling pathways, but the receptor mechanisms responsible for this are not understood. We have identified a specific polyproline motif in the amino-terminal domain of conventional progesterone receptor (PR) that mediates direct progestin-dependent interaction of PR with SH3 domains of various cytoplasmic signaling molecules, including c-Src tyrosine kinases. Through this interaction, PR is a potent activator of Src kinases working by an SH3 domain displacement mechanism. By mutagenesis, we also show that rapid progestin-induced activation of Src and downstream MAP kinase in mammalian cells is dependent on PR-SH3 domain interaction, but not on the transcriptional activity of PR. Preliminary evidence for the biological significance of this PR signaling pathway through regulatory SH3 domains was shown with respect to an influence on progestin-induced growth arrest of breast epithelial cells and induction of Xenopus oocyte maturation.