Abstract B73: Human omental-derived adipose stem cells: Modulator of ovarian cancer proliferation, migration and chemoresistance

Objectives: Adipose tissue contains a population of multipotent mesenchymal stromal cells (ASC) which exhibit tumor tropism, similar to bone marrow derived mesenchymal stem cells (MSC). Excess visceral adipose tissue increases the risk of ovarian cancer. The omentum is a prominent site for ovarian cancer metastasis. We hypothesize that the omentum serves as a source of ASC which promote ovarian cancer progression.

Materials and Methods: ASC were isolated from the omentum (O-ASCs) of three patients with ovarian cancer. O-ASC1 was isolated from a patient with synchronous adenocarcinoma of endometrial and ovarian cancer without peritoneal metastasis; and O-ASC4 and O-ASC5 were isolated from patients with peritoneally disseminated serous ovarian cancer. Gene expression array profiling was performed with using Nimblegen arrays (Roche NimbleGen, Inc., Madison, WI). The impact of stromal cells on proliferation and chemoresistane and radio-protection of ovarian cancer cells was tested with co-culture assays using luciferase-labeled human ovarian cancer cell lines. Transwell migration assays were performed with conditioned media from O-ASC and control cell lines. To evaluate of O-ASCs tumor tropism in-vivo experiment was performed.

Results: Human O-ASCs were detected engrafted within the stroma of human ovarian cancer xengrafts. O-ASC significantly promoted in-vitro proliferation and migration of ovarian cancer cell lines OVCA 429, OVCA 433, A2780. Co-culture of ovarian cancer cells with O-ASCs increased resistance to chemotherapeutic drugs and radiation. Gene expression array analysis revealed significant differences in expression profiles for group of 415 genes in sub-populations of O-ASCs.

Conclusions: Adipose stem cells derived from human omentum promoted the proliferation, migration, chemoresistance and radioresistance of ovarian cancers. Clinical isolates demonstrate heterogenous effects in- vitro. Future studies will determine if tumor promoting effects of O-ASC can be predicted on the basis of clinical or disease related characteristics.

Citation Format: Aleksandra Nowicka, Travis Solley, Frank C. Marini, Hadley J. Sharp, Russell R. Broaddus, Kolonin G. Mikhail, Samuel C. Mok, Wendy A. Woodward, Karen H. Lu, Ann H. Klopp. Human omental-derived adipose stem cells: Modulator of ovarian cancer proliferation, migration and chemoresistance. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B73.

The antihelmintic drug pyrvinium pamoate targets aggressive breast cancer

WNT signaling plays a key role in the self-renewal of tumor initiation cells (TICs). In this study, we used pyrvinium pamoate (PP), an FDA-approved antihelmintic drug that inhibits WNT signaling, to test whether pharmacologic inhibition of WNT signaling can specifically target TICs of aggressive breast cancer cells. SUM-149, an inflammatory breast cancer cell line, and SUM-159, a metaplastic basal-type breast cancer cell line, were used in these studies. We found that PP inhibited primary and secondary mammosphere formation of cancer cells at nanomolar concentrations, at least 10 times less than the dose needed to have a toxic effect on cancer cells. A comparable mammosphere formation IC50 dose to that observed in cancer cell lines was obtained using malignant pleural effusion samples from patients with IBC. A decrease in activity of the TIC surrogate aldehyde dehydrogenase was observed in PP-treated cells, and inhibition of WNT signaling by PP was associated with down-regulation of a panel of markers associated with epithelial-mesenchymal transition. In vivo, intratumoral injection was associated with tumor necrosis, and intraperitoneal injection into mice with tumor xenografts caused significant tumor growth delay and a trend toward decreased lung metastasis. In in vitro mammosphere-based and monolayer-based clonogenic assays, we found that PP radiosensitized cells in monolayer culture but not mammosphere culture. These findings suggest WNT signaling inhibition may be a feasible strategy for targeting aggressive breast cancer. Investigation and modification of the bioavailability and toxicity profile of systemic PP are warranted.

Involved-field radiation therapy for locoregionally recurrent ovarian cancer

OBJECTIVE

To evaluate the effectiveness of definitive involved-field radiation therapy (IFRT) for selected patients with locoregionally-recurrent ovarian cancer.

METHODS

We retrospectively reviewed records of 102 epithelial ovarian cancer patients treated with definitive IFRT (≥45Gy). IFRT was directed to localized nodal (49%) and extranodal (51%) recurrences.

RESULTS

The median time from diagnosis to IFRT was 36 months (range, 1-311), and the median follow-up after IFRT was 37 months (range, 1-123). Patients received a median of three chemotherapy courses before IFRT (range, 0-9). Five-year overall (OS) and progression-free survival (PFS) rates after IFRT were 40% and 24% respectively; the 5-year in-field disease control rate was 71%. Thirty-five patients (35%) had no evidence of disease at a median of 38 months after IFRT (range, 7-122), including 25 continuously without disease for a median of 61 months (range, 17-122) and 10 with salvage treatment following disease recurrence, disease-free for a median of 39 months after salvage treatment (range, 7-92). Eight clear cell carcinoma patients had higher 5-year OS (88% versus 37%; p=0.05) and PFS (75% versus 20%; p=0.01) rates than other patients. Patients sensitive to initial platinum chemotherapy had a higher 5-year OS rate than platinum-resistant patients (43% versus 27%, p=0.03). Patients who required chemotherapy for recurrence after IFRT often benefitted from longer chemotherapy-free intervals after than before IFRT.

CONCLUSIONS

Definitive IFRT can yield excellent local control, protracted disease-free intervals, and even cures in carefully selected patients. RT should be considered a tool in the curative management of locoregionally-recurrent ovarian cancer.

Commissioning of a grid-based Boltzmann solver for cervical cancer brachytherapy treatment planning with shielded colpostats

PURPOSE

We sought to commission a gynecologic shielded colpostat analytic model provided from a treatment planning system (TPS) library. We have reported retrospectively the dosimetric impact of this applicator model in a cohort of patients.

METHODS AND MATERIALS

A commercial TPS with a grid-based Boltzmann solver (GBBS) was commissioned for (192)Ir high-dose-rate (HDR) brachytherapy for cervical cancer with stainless steel-shielded colpostats. Verification of the colpostat analytic model was verified using a radiograph and vendor schematics. MCNPX v2.6 Monte Carlo simulations were performed to compare dose distributions around the applicator in water with the TPS GBBS dose predictions. Retrospectively, the dosimetric impact was assessed over 24 cervical cancer patients' HDR plans.

RESULTS

Applicator (TPS ID #AL13122005) shield dimensions were within 0.4 mm of the independent shield dimensions verification. GBBS profiles in planes bisecting the cap around the applicator agreed with Monte Carlo simulations within 2% at most locations; differing screw representations resulted in differences of up to 9%. For the retrospective study, the GBBS doses differed from TG-43 as follows (mean value ± standard deviation [min, max]): International Commission on Radiation units [ICRU]rectum (-8.4 ± 2.5% [-14.1, -4.1%]), ICRUbladder (-7.2 ± 3.6% [-15.7, -2.1%]), D2cc-rectum (-6.2 ± 2.6% [-11.9, -0.8%]), D2cc-sigmoid (-5.6 ± 2.6% [-9.3, -2.0%]), and D2cc-bladder (-3.4 ± 1.9% [-7.2, -1.1%]).

CONCLUSIONS

As brachytherapy TPSs implement advanced model-based dose calculations, the analytic applicator models stored in TPSs should be independently validated before clinical use. For this cohort, clinically meaningful differences (>5%) from TG-43 were observed. Accurate dosimetric modeling of shielded applicators may help to refine organ toxicity studies.

Hematologic toxicity in RTOG 0418: a phase 2 study of postoperative IMRT for gynecologic cancer

PURPOSE

Intensity modulated radiation therapy (IMRT), compared with conventional 4-field treatment, can reduce the volume of bone marrow irradiated. Pelvic bone marrow sparing has produced a clinically significant reduction in hematologic toxicity (HT). This analysis investigated HT in Radiation Therapy Oncology Group (RTOG) 0418, a prospective study to test the feasibility of delivering postoperative IMRT for cervical and endometrial cancer in a multiinstitutional setting.

METHODS AND MATERIALS

Patients in the RTOG 0418 study were treated with postoperative IMRT to 50.4 Gy to the pelvic lymphatics and vagina. Endometrial cancer patients received IMRT alone, whereas patients with cervical cancer received IMRT and weekly cisplatin (40 mg/m(2)). Pelvic bone marrow was defined within the treatment field by using a computed tomography density-based autocontouring algorithm. The volume of bone marrow receiving 10, 20, 30, and 40 Gy and the median dose to bone marrow were correlated with HT, graded by Common Terminology Criteria for Adverse Events, version 3.0, criteria.

RESULTS

Eighty-three patients were eligible for analysis (43 with endometrial cancer and 40 with cervical cancer). Patients with cervical cancer treated with weekly cisplatin and pelvic IMRT had grades 1-5 HT (23%, 33%, 25%, 0%, and 0% of patients, respectively). Among patients with cervical cancer, 83% received 5 or more cycles of cisplatin, and 90% received at least 4 cycles of cisplatin. The median percentage volume of bone marrow receiving 10, 20, 30, and 40 Gy in all 83 patients, respectively, was 96%, 84%, 61%, and 37%. Among cervical cancer patients with a V40 >37%, 75% had grade 2 or higher HT compared with 40% of patients with a V40 less than or equal to 37% (P =.025). Cervical cancer patients with a median bone marrow dose of >34.2 Gy also had higher rates of grade ≥ 2 HT than did those with a dose of ≤ 34.2 Gy (74% vs 43%, P=.049).

CONCLUSIONS

Pelvic IMRT with weekly cisplatin is associated with low rates of HT and high rates of weekly cisplatin use. The volume of bone marrow receiving 40 Gy and the median dose to bone marrow correlated with higher rates of grade ≥ 2 toxicity among patients receiving weekly cisplatin (cervical cancer patients). Evaluation and limitation of the volume of bone marrow treated with pelvic IMRT is warranted in patients receiving concurrent chemotherapy.

Abstract 1854: Metabolic cross talk between omental derived adipose stromal cells from lean and obese patients with ovarian cancer cells

Advanced-stage ovarian cancers have been shown to be metastatic in peritoneal cavity. Ovarian cancer metastasis is diagnosed primarily in omentum which is a soft fatty pad that extends from stomach and covers the bowel. The location of excess adipose tissue appears to be an important factor which influences the effect of obesity on cancer incidence. For example, increased total body obesity is associated with relative risk of 1.14 of developing ovarian cancer. However, a waist to hip circumference ratio of >0.85 is associated with a much higher 8-fold increased risk of developing ovarian cancer. Individuals with greater waist to hip ratio generally have more visceral adipose including omental adipose. The tumor promoting effects of regional adipose may be attributed, at least in part, to the presence of a population of mesenchymal stem cells (MSC) in adipose tissue. Adipose stem cells or adipose derived stromal cells (ASCs) are a multi-potent population of mesenchymal stem cells, which support cancer progression in many models. These cells are uniquely tumor tropic, migrating into tumor stroma from regional sources where they support formation of tumor stroma elements and promote tumor progression. Here, we use metabolic foot-printing approach to dissect the metabolic networks regulated by ASCs and ACs, as well as their role in imparting drug resistance to tumors by deregulating metabolic pathways in ovarian cancer cells. Importantly, we found that O-ASCs from obese patients differentially induce metabolic reprogramming in cancer cells and that cancer cells induce reciprocal metabolic alterations and phenotypic changes in O-ASCs from lean patients.

Citation Format: Bahar Salimian Rizi, Alexandra Nowicka, Ann H. Klopp, Deepak Nagrath. Metabolic cross talk between omental derived adipose stromal cells from lean and obese patients with ovarian cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1854. doi:10.1158/1538-7445.AM2013-1854

Pilot study of a computed tomography-compatible shielded intracavitary brachytherapy applicator for treatment of cervical cancer

PURPOSE

The traditional Fletcher-Williamson tandem and ovoid brachytherapy applicators for treatment of cervical cancer have ovoid shields that reduce the dose to the bladder and rectum. However, these shields produce artifact on computed tomography (CT) that prevents acquisition of high-quality images. To address this limitation, we designed and tested a novel CT-compatible applicator with movable shields, called MDA(3).

METHODS AND MATERIALS

Fifteen patients with stage IB1-IIB cervical cancer requiring definitive radiation therapy were enrolled in a prospective pilot study to evaluate image quality with the MDA(3). Image quality was assessed by comparing an initial scan obtained with the shields shifted to minimize shield artifact to a second scan obtained with the shields in treatment position. The 2 scans were then compared by a radiation oncologist blinded to the image source. In addition, image quality was assessed by analysis of Hounsfield values in the normal tissues.

RESULTS

The MDA(3) was successfully employed for intracavitary brachytherapy in 15 patients. CT images obtained with the shields shifted were superior to CT images obtained with the shields in treatment position in every case as evaluated by the radiation oncologist (P < .0001). The presence of the shields in the treatment position significantly increased the mean Hounsfield values within the bladder (P = .002) and rectum (P = .001) due to high-density image artifact.

CONCLUSIONS

This novel applicator provides a clinically feasible solution to overcome the limitation of lack of ovoid shields on currently available CT-compatible applicators.

Biological predictors of cervical cancer response to radiation therapy

The addition of cisplatin-based chemotherapy to standard radiation therapy reduces the risk of recurrence and disease-related death rates from locally advanced cervical cancers by as much as 50%. However, the absolute gains are relatively small for patients with early tumors, many of whom would have been cured with radiation alone, and recurrence rates are still high for patients who have very large or advanced-stage tumors. As a result, there is a pressing need for more accurate predictors of radiocurability. A variety of types of biomarkers have been shown to correlate with cervical cancer response to radiation therapy. These include traditional clinical and morphologic predictors, non-molecular biomarkers, including hypoxia and fluorodeoxyglucose-positron emission tomography (FDG-PET) avidity, as well as molecular biomarkers, which include single-gene markers or array-based multigene predictors. Multi-gene predictors of response remain immature in cervical cancer, but studies thus far have paved the way for future studies to validate these findings. Methods will need to be standardized and markers will need to be validated on homogeneous patient populations and treatment approaches before they can become useful tools for clinical decision making. In addition, new biomarkers will be of major value only if they add to the predictive value of traditional clinical and morphologic predictors. Ultimately, the most useful biomarkers will identify patients who will benefit from specific molecularly targeted agents in addition to radiation therapy or perhaps identify patient who are at low risk for recurrence, for whom the dose of radiation or chemotherapy can be reduced.

Intensity modulated radiation therapy for definitive treatment of paraortic relapse in patients with endometrial cancer

PURPOSE

The paraortic nodes are a common site of recurrence of endometrial cancer, especially among patients previously treated with pelvic radiation. Intensity modulated radiation therapy (IMRT) can be used to deliver a tumoricidal dose to paraortic disease while minimizing dose to normal adjacent structures. In this study, we reviewed the outcomes of patients treated with IMRT for unresected or incompletely resected paraortic recurrences of primary uterine cancer.

METHODS AND MATERIALS

Between 2000 and 2009, 27 patients with unresected (19 patients) or incompletely resected (8 patients) paraortic relapse of endometrial cancer were treated with curative intent using IMRT. The paraortic basin was generally treated to a dose of 45-50 Gy, and gross disease was treated to a mean total dose of 61.7 Gy (range, 54-66 Gy). Seventeen patients (63%) received neoadjuvant or adjuvant chemotherapy. Fifteen (56%) received cisplatin concurrently with IMRT. Rates of overall survival and progression-free survival following salvage IMRT were determined using the Kaplan-Meier method, and differences between subgroups were assessed using the log-rank statistic.

RESULTS

Of the 27 patients, 19 (70%) had local control of paraortic disease after a median follow-up time of 25 months (range, 4-83 months). Two-year actuarial overall survival and progression-free survival rates were 63% and 53%, respectively. Five patients (19%) experienced severe late gastrointestinal toxic effects (grade 3-5).

CONCLUSIONS

IMRT can serve as salvage therapy of paraortic recurrence of endometrial cancer. However, the risk of severe gastrointestinal toxic effects is high, and care should be taken during treatment planning to minimize the dose to the small bowel.

Abstract 5210: Impact of tumor microenvironment on expansion of tumor initiating cells in breast cancer metastasis

Breast cancer metastasis which ultimately results in breast cancer death, is an event believed to be initiated by the migration of tumor initiating cells (TIC) from the primary tumor to niches for micrometastatic disease. Recent data suggests the tumor microenvironment promotes TIC. The clinical relevance of secreted factors from the microenvironment on TIC surrogate, mammosphere (MS) formation and MS sensitivity to drug therapy was investigated using breast cancer patient fluids inherently conditioned by the tumor microenvironment: post-operative seromas and malignant pleural effusions. Fluids from 20 patients with breast cancer (8 seromas and 13 pleural effusions) and mesenchymal stem cells (MSC) from healthy donors were collected on IRB approved protocols. Cellular components were eliminated from patient-derived fluids using density-gradient centrifugation. MSC conditioned media (MSC-CM) was collected from 3D cultures of primary MSC. Luminex multiplex array platform was used to characterize 79 cytokine and growth factor components of all fluids. In addition, MSC-CM and patient-derived fluids were added to cultures of breast cancer cell lines: MCF-7, an estrogen receptor (ER)-positive cell line; SUM149, a triple-negative inflammatory breast cancer cell line; and SUM159, a triple-negative metaplastic breast cancer cell line and MS forming efficiency was examined. Our results show that pleural effusions and seromas are enriched for factors also secreted by MSC such as MCP-1, GRO, IL-6 and IL-8. We found remarkable similarities regarding the cytokines and growth factors profile in pleural effusions and seromas. Both patient-derived fluids have comparable amount of IL-2, IL-3, IL-4 and IL-10, as well as, VEGF, EGF and FGF-b. IL-1β and IL-16 were significantly different between pleural effusions and seromas. Seroma fluid from bilateral drains in a patient with an invasive cancer and a contralateral benign mastectomy had very similar cytokine concentrations. Moreover, MSC-CM and pleural fluids from ER+ and ER- patients increased the MS formation efficiency of both triple-negative cell lines while seroma fluids from ER+ and ER- patients increased the MS formation efficiency of ER-positive cell line MCF-7. Finally, we evaluated the impact of a panel of drugs on cell cultures grown with MSC-CM and patient-derived fluids. We found that the effect of chemotherapies on MS formation can be attenuated by patient-derived fluids. Seroma and pleural effusion fluids from breast cancer patients have similar cytokine profiles, change MS formation efficiency of standard breast cancer cell models, and mediate sensitivity to therapy. Here we demonstrate that host and microenvironmental factors are critical for determining resistance to therapy. Future studies will investigate the prognostic implications of factors that promote TIC survival in the fluid tumor microenvironment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5210. doi:1538-7445.AM2012-5210

Abstract 1492: Eavesdropping of crosstalk between adipose stem cells (ASC) and ovarian cancer cells

Background Adipose tissue contains a population of multipotent adipose stromal cells (ASC) which migrate into tumors and form supportive tumor stroma elements. ASCs release various growth factors, cytokines and metabolites that influence on physiochemical nature of the local environment. Ovarian cancer cells have a predilection for metastasis in omentum, the primary repository for visceral adipose. The effects of omental derived adipose stem cells (O-ASC) and subcutaneous tissue derived adipose stem cells (SC-ASC) on ovarian cancer biology including ovarian cancer proliferation, gene expression and response to chemotherapy were investigated. Methods and Results Luciferase labelled ovarian carcinoma cells (OVCA 429) were co-cultured with O-ASC, SC-ASC and control fibroblast line Wi38. Significantly higher levels of luciferase activity was detected when ovarian carcinoma cells were co-cultured with O-ASC than with SC-ASC and Wi38 (3470.4 RLU vs 1253.2 RLU, p=&lt;0.005). Moreover, co-culture of 429 cells with ASCs in presence of different concentrations of Taxol revealed that O-ASC influence tumor cell chemosensitivity. Additionally, O-ASC promoted formation of significantly more ovarian carcinoma tumorispheres which were more closer associated to each other than those created in sphere medium only. To identify differentially expressed genes in O-ASC and SC-ASC, we performed microarray experiments (NimbleGen platform) which were analyzed using Ingenuity Pathway Analysis (IPA) software. The highest expressed genes were connected with growth, proliferation and development of cells and most of the proteins coded by these genes were localized in the extracellular space, plasma membrane or exosomes (CALR, UNC5B in O-ASC or COL1A2, FN1 in SC-ASC). We also performed ELISA assays focused on release of growth factors which revealed that O-ASC and SC-ASC secrete more VEGF (1678 pg/ml) and FGF (29 pg/ml) compared to control cells Wi38 (114 pg/ml and 2.7 pg/ml respectively). Chemokine SDF-1α was also secreted in high level by O-ASC S1 (1537 pg/ml) but SC-ASC released only 187 pg/ml relative to Wi38 (706 pg/ml) which indicates that these two types of adipose stem cells can create different surrounding environment. Summary O-ASC cells have unique tumor promoting effects and create specific environmental niche by releasing growth factors, cytokines and other factors which can stimulate ovarian cancer cells to grow faster and clump together. ASC may also influence protection of ovarian cancer from toxicity of chemotherapeutics. The knowledge about microenvironmental crosstalk between normal stem cells and tumor cells can contribute in the development of new treatment to prevent metastasis of ovarian cancer and make them vulnerable to chemotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1492. doi:1538-7445.AM2012-1492

Anatomic distribution of [(18)F] fluorodeoxyglucose-avid lymph nodes in patients with cervical cancer

PURPOSE

Current information about the anatomic distribution of lymph node (LN) metastases from cervical cancer is not precise enough for optimal treatment planning for highly conformal radiation therapy. To accurately define the anatomic distribution of these LN metastases, we mapped [(18)F] fluorodeoxyglucose positron emission tomography (FDG PET)-positive LNs from 50 women with cervical cancer.

METHODS AND MATERIALS

Records of patients with cervical cancer treated from 2006 to 2010 who had pretreatment PET/computed tomography (CT) scans available were retrospectively reviewed. Forty-one consecutive patients (group 1) with FDG-avid LNs were identified; because there were few positive paraortic LNs in group 1, 9 additional patients (group 2) with positive paraortic LNs were added. Involved LNs were contoured on individual PET/CT images, mapped to a template CT scan by deformable image registration, and edited as necessary by a diagnostic radiologist and radiation oncologists to most accurately represent the location on the original PET/CT scan.

RESULTS

We identified 190 FDG-avid LNs, 122 in group 1 and 68 in group 2. The highest concentrations of FDG-avid nodes were in the external iliac, common iliac, and paraortic regions. The anatomic distribution of the 122 positive LNs in group 1 was as follows: external iliac, 78 (63.9%); common iliac, 21 (17.2%); paraortic, 9 (7.4%); internal iliac, 8 (6.6%); presacral, 2 (1.6%); perirectal, 2 (1.6%); and medial inguinal, 2 (1.6%). Twelve pelvic LNs were not fully covered when the clinical target volume was defined according to Radiation Therapy Oncology Group guidelines for intensity modulated radiation therapy for cervical cancer.

CONCLUSIONS

Our findings clarify nodal volumes at risk and can be used to improve target definition in conformal radiation therapy for cervical cancer. Our findings suggest several areas that may not be adequately covered by contours described in available atlases.

Impact of heterogeneity-based dose calculation using a deterministic grid-based Boltzmann equation solver for intracavitary brachytherapy

PURPOSE

To investigate the dosimetric impact of the heterogeneity dose calculation Acuros (Transpire Inc., Gig Harbor, WA), a grid-based Boltzmann equation solver (GBBS), for brachytherapy in a cohort of cervical cancer patients.

METHODS AND MATERIALS

The impact of heterogeneities was retrospectively assessed in treatment plans for 26 patients who had previously received (192)Ir intracavitary brachytherapy for cervical cancer with computed tomography (CT)/magnetic resonance-compatible tandems and unshielded colpostats. The GBBS models sources, patient boundaries, applicators, and tissue heterogeneities. Multiple GBBS calculations were performed with and without solid model applicator, with and without overriding the patient contour to 1 g/cm(3) muscle, and with and without overriding contrast materials to muscle or 2.25 g/cm(3) bone. Impact of source and boundary modeling, applicator, tissue heterogeneities, and sensitivity of CT-to-material mapping of contrast were derived from the multiple calculations. American Association of Physicists in Medicine Task Group 43 (TG-43) guidelines and the GBBS were compared for the following clinical dosimetric parameters: Manchester points A and B, International Commission on Radiation Units and Measurements (ICRU) report 38 rectal and bladder points, three and nine o'clock, and (D2cm3) to the bladder, rectum, and sigmoid.

RESULTS

Points A and B, D(2) cm(3) bladder, ICRU bladder, and three and nine o'clock were within 5% of TG-43 for all GBBS calculations. The source and boundary and applicator account for most of the differences between the GBBS and TG-43 guidelines. The D(2cm3) rectum (n = 3), D(2cm3) sigmoid (n = 1), and ICRU rectum (n = 6) had differences of >5% from TG-43 for the worst case incorrect mapping of contrast to bone. Clinical dosimetric parameters were within 5% of TG-43 when rectal and balloon contrast were mapped to bone and radiopaque packing was not overridden.

CONCLUSIONS

The GBBS has minimal impact on clinical parameters for this cohort of patients with unshielded applicators. The incorrect mapping of rectal and balloon contrast does not have a significant impact on clinical parameters. Rectal parameters may be sensitive to the mapping of radiopaque packing.

Omental adipose tissue-derived stromal cells promote vascularization and growth of endometrial tumors

PURPOSE

Adipose tissue contains a population of tumor-tropic mesenchymal progenitors, termed adipose stromal cells (ASC), which engraft in neighboring tumors to form supportive tumor stroma. We hypothesized that intra-abdominal visceral adipose tissue may contain a uniquely tumor-promoting population of ASC to account for the relationship between excess visceral adipose tissue and mortality of intra-abdominal cancers.

EXPERIMENTAL DESIGN

To investigate this, we isolated and characterized ASC from intra-abdominal omental adipose tissue (O-ASC) and characterized their effects on endometrial cancer progression as compared with subcutaneous adipose-derived mesenchymal stromal cells (SC-ASC), bone marrow-derived mesenchymal stromal cells (BM-MSC), and lung fibroblasts. To model chronic recruitment of ASC by tumors, cells were injected metronomically into mice bearing Hec1a xenografts.

RESULTS

O-ASC expressed cell surface markers characteristic of BM-MSC and differentiated into mesenchymal lineages. Coculture with O-ASC increased endometrial cancer cell proliferation in vitro. Tumor tropism of O-ASC and SC-ASC for human Hec1a endometrial tumor xenografts was comparable, but O-ASC more potently promoted tumor growth. Compared with tumors in SC-ASC-injected mice, tumors in O-ASC-injected mice contained higher numbers of large tortuous desmin-positive blood vessels, which correlated with decreased central tumor necrosis and increased tumor cell proliferation. O-ASC exhibited enhanced motility as compared with SC-ASC in response to Hec1a-secreted factors.

CONCLUSIONS

Visceral adipose tissue contains a population of multipotent MSCs that promote endometrial tumor growth more potently than MSCs from subcutaneous adipose tissue. We propose that O-ASCs recruited to tumors express specific factors that enhance tumor vascularization, promoting survival and proliferation of tumor cells.

Concise review: Dissecting a discrepancy in the literature: do mesenchymal stem cells support or suppress tumor growth?

The discovery that mesenchymal stem cells (MSCs) are recruited into tumors has led to a great deal of interest over the past decade in the function of MSCs in tumors. To address this, investigators have used a variety of tumor models in which MSCs are added exogenously to determine their impact on tumor development. Interestingly, many studies have reported contradicting results, with some investigators finding that MSCs promote tumor growth and others reporting that MSCs inhibit tumor growth. Many mechanisms have been reported to account for these observations, such as chemokine signaling, modulation of apoptosis, vascular support, and immune modulation. In this review, we analyzed the differences in the methodology of the studies reported and found that the timing of MSC introduction into tumors may be a critical element. Understanding the conditions in which MSCs enhance tumor growth and metastasis is crucial, both to safely develop MSCs as a therapeutic tool and to advance our understanding of the role of tumor stroma in carcinogenesis.

Mesenchymal stem cells promote mammosphere formation and decrease E-cadherin in normal and malignant breast cells

INTRODUCTION

Normal and malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew, referred to as stem cells, or tumor initiating cells (TIC). These cells can be enriched by growth as "mammospheres" in three-dimensional cultures.

OBJECTIVE

We tested the hypothesis that human bone-marrow derived mesenchymal stem cells (MSC), which are known to support tumor growth and metastasis, increase mammosphere formation.

RESULTS

We found that MSC increased human mammary epithelial cell (HMEC) mammosphere formation in a dose-dependent manner. A similar increase in sphere formation was seen in human inflammatory (SUM149) and non-inflammatory breast cancer cell lines (MCF-7) but not in primary inflammatory breast cancer cells (MDA-IBC-3). We determined that increased mammosphere formation can be mediated by secreted factors as MSC conditioned media from MSC spheroids significantly increased HMEC, MCF-7 and SUM149 mammosphere formation by 6.4 to 21-fold. Mammospheres grown in MSC conditioned media had lower levels of the cell adhesion protein, E-cadherin, and increased expression of N-cadherin in SUM149 and HMEC cells, characteristic of a pro-invasive mesenchymal phenotype. Co-injection with MSC in vivo resulted in a reduced latency time to develop detectable MCF-7 and MDA-IBC-3 tumors and increased the growth of MDA-IBC-3 tumors. Furthermore, E-cadherin expression was decreased in MDA-IBC-3 xenografts with co-injection of MSC.

CONCLUSIONS

MSC increase the efficiency of primary mammosphere formation in normal and malignant breast cells and decrease E-cadherin expression, a biologic event associated with breast cancer progression and resistance to therapy.

Abstract 560: Mesenchymal stem cells promote mammosphere formation in normal and malignant breast cells

Purpose: Normal and malignant breast tissue contains a rare population of cells with the capacity to self-renew, referred to as stem cells, or tumor initiating cells (TIC) in the case of tumors. These cells can be enriched by growth as “mammospheres” in three-dimensional cultures. We tested the hypothesis that mesenchymal stem cells (MSC), which are known to support tumor growth and metastasis, increase mammosphere formation.

Materials and Methods: Normal human mammary epithelial cells (HMEC), and breast cancer cells (MCF-7, SUM149 and IBC3) were grown as mammospheres, plated at low density in serum-free growth factor supplemented suspension cultures. MSC were added as an increasing percentage of total cells plated (0, 2, 5 and 10%). MSC-conditioned media was generated by growing MSC as spheroids for 5 days.

Results: MSC integrated into mammospheres, resulting in a dose-dependent increase in the number of mammospheres formed. Normal mammary epithelial cells formed 1.6 to 2.4 to 2.7-fold (p&lt; 0.001) more mammospheres in the presence of 2, 5 and 10% MSC. Similarly, the number of MCF-7 derived mammospheres increased 5.9 to 8.5 to14.8-fold (p = ≤ 0.001) in the presence of 2, 5 and 10% MSC. A similar dose-dependent increase in sphere formation was seen for SUM149 cells and inflammatory breast cancer cells in short-term culture derived from pleural effusions. This effect was found to be mediated by secreted factors as MSC-conditioned media also increased sphere formation. SUM149 cells formed 6.4 to 14.2 to 13.7-fold more mammospheres when incubated for 5 days in 5, 25 and 50% MSC conditioned-media (p &lt;0.0001). HMEC derived mammospheres had higher levels of expression of N-cadherin and RhoC and lower levels of expression of E-cadherin and Notch when formed in the presence of MSC conditioned media.

Conclusions: Mesenchymal stem cells increase mammosphere formation of normal breast epithelial cells, established cancer cell lines (MCF-7 and SUM149) and short term primary breast cancer cells (IBC3). This effect is mediated by MSC secreted factors and results in cadherin switching, which may promote breast cancer progression and resistance to therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 560.

Expression of nuclear transcription factor kappa B in locally advanced human cervical cancer treated with definitive chemoradiation

PURPOSE

Nuclear factor kappa B (NF-κB), a transcriptional factor that has been shown to be constitutively active in cervical cancer, is part of an important pathway leading to treatment resistance in many tumor types. The purpose of our study was to determine whether expression of NF-κB in pretreatment specimens and specimens taken shortly after treatment initiation correlated with outcome in cervical cancer patients treated with definitive chemoradiation.

METHODS AND MATERIALS

Eighteen patients with locally advanced cervical cancer were enrolled in a study in which cervical biopsy specimens were obtained before radiation therapy and 48 h after treatment initiation. Matched biopsy specimens from 16 of these patients were available and evaluated for the nuclear expression of NF-κB protein by immunohistochemical staining.

RESULTS

After a median follow-up of 43 months, there were 9 total treatment failures. Nuclear staining for NF-κB was positive in 3 of 16 pretreatment biopsy specimens (19%) and 5 of 16 postradiation biopsy specimens (31%). Pretreatment expression of NF-κB nuclear staining correlated with increased rates of local-regional failure (100% vs. 23%, p = 0.01), distant failure (100% vs. 38%, p = 0.055), disease-specific mortality (100% vs. 31%, p = 0.03), and overall mortality (100% vs. 38%, p = 0.055).

CONCLUSIONS

Our data suggest that pretreatment nuclear expression of NF-κB may be associated with a poor outcome for cervical cancer patients treated with chemoradiation. Although these data require validation in a larger group of patients, the results support the continued study of the relationship between NF-κB and outcome in patients treated for carcinoma of the cervix.

Node-positive adenocarcinoma of the endometrium: outcome and patterns of recurrence with and without external beam irradiation

OBJECTIVE

To evaluate treatment outcomes and patterns of recurrence in patients with node-positive (International Federation of Obstetrics and Gynecology stage IIIC) adenocarcinoma of the uterus without serous or clear cell differentiation.

METHODS

The records of 71 women who were treated for stage IIIC endometrial adenocarcinoma at our institution between 1984 and 2005 were reviewed. All patients underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, and lymphadenectomy. Fifty patients received definitive pelvic or extended-field radiotherapy with or without systemic therapy (regional RT group). Eighteen received adjuvant systemic platinum-based chemotherapy or hormonal therapy without external beam RT. The median follow-up for patients not dying of disease was 67 months. Survival rates were calculated using the Kaplan-Meier method; differences were assessed using log-rank tests.

RESULTS

Thirty-nine percent (28/71) of patients had involved paraaortic lymph nodes while 61% (43/71) had only pelvic lymph nodes. Five- and 10-year disease-specific survival (DSS) rates were 63% and 54%, respectively; corresponding overall survival rates were 60% and 47%. Grade was strongly associated with DSS (76% vs 46% at 5 years for low-grade vs high-grade tumors, P=0.004). Cervical or adnexal involvement was associated with decreased DSS, but lymph-vascular space invasion, age, race, body mass index, and number and location of positive nodes were not. Five-year pelvic-relapse-free survival (98% vs 61%, P=0.001), DSS (78% vs 39%, P=0.01), and overall survival (73% vs 40%, P=0.03) were significantly better for the regional RT group than the systemic therapy group. In patients treated without regional RT, the most common site of relapse was the pelvis. DSS was not significantly correlated with number of nodes removed in the regional RT group but was in patients treated without regional RT (P=0.001).

CONCLUSIONS

Patients treated without regional RT had a high rate of locoregional recurrence. Patients with stage IIIC endometrial adenocarcinoma who underwent surgical staging followed by external beam irradiation had a high rate of cure. Relapses in patients treated with EBRT primarily occurred in patients with grade 3 cancer who may be most likely to benefit from combined-chemoradiation treatment.

Exclusion of elective nodal irradiation is associated with minimal elective nodal failure in non-small cell lung cancer

BACKGROUND

Controversy still exists regarding the long-term outcome of patients whose uninvolved lymph node stations are not prophylactically irradiated for non-small cell lung cancer (NSCLC) treated with definitive radiotherapy. To determine the frequency of elective nodal failure (ENF) and in-field failure (IFF), we examined a large cohort of patients with NSCLC staged with positron emission tomography (PET)/computed tomography (CT) and treated with 3-dimensional conformal radiotherapy (3D-CRT) that excluded uninvolved lymph node stations.

METHODS

We retrospectively reviewed the records of 115 patients with non-small cell lung cancer treated at our institution with definitive radiation therapy with or without concurrent chemotherapy (CHT). All patients were treated with 3D-CRT, including nodal regions determined by CT or PET to be disease involved. Concurrent platinum-based CHT was administered for locally advanced disease. Patients were analyzed in follow-up for survival, local regional recurrence, and distant metastases (DM).

RESULTS

The median follow-up time was 18 months (3 to 44 months) among all patients and 27 months (6 to 44 months) among survivors. The median overall survival, 2-year actuarial overall survival and disease-free survival were 19 months, 38%, and 28%, respectively. The majority of patients died from DM, the overall rate of which was 36%. Of the 31 patients with local regional failure, 26 (22.6%) had IFF, 5 (4.3%) had ENF and 2 (1.7%) had isolated ENF. For 88 patients with stage IIIA/B, the frequencies of IFF, any ENF, isolated ENF, and DM were 23 (26%), 3 (9%), 1 (1.1%) and 36 (40.9%), respectively. The comparable rates for the 22 patients with early stage node-negative disease (stage IA/IB) were 3 (13.6%), 1(4.5%), 0 (0%), and 5 (22.7%), respectively.

CONCLUSION

We observed only a 4.3% recurrence of any ENF and a 1.7% recurrence of isolated ENF in patients with NSCLC treated with definitive 3D-CRT without prophylactic irradiation of uninvolved lymph node stations. Thus, distant metastasis and IFF remain the primary causes of treatment failure and cancer death in such patients, suggesting little value of ENI in this cohort.

Gene expression changes in cervical squamous cell carcinoma after initiation of chemoradiation and correlation with clinical outcome

PURPOSE

The purpose of this study was to investigate early gene expression changes after chemoradiation in a human solid tumor, allowing identification of chemoradiation-induced gene expression changes in the tumor as well as the tumor microenvironment. In addition we aimed to identify a gene expression profile that was associated with clinical outcome.

METHODS AND MATERIALS

Microarray experiments were performed on cervical cancer specimens obtained before and 48 h after chemoradiation from 12 patients with Stage IB2 to IIIB squamous cell carcinoma of the cervix treated between April 2001 and August 2002.

RESULTS

A total of 262 genes were identified that were significantly changed after chemoradiation. Genes involved in DNA repair were identified including DDB2, ERCC4, GADD45A, and XPC. In addition, significantly regulated cell-to-cell signaling pathways included insulin-like growth factor-1 (IGF-1), interferon, and vascular endothelial growth factor signaling. At a median follow-up of 41 months, 5 of 12 patients had experienced either local or distant failure. Supervised clustering analysis identified a 58-gene set from the pretreatment samples that were differentially expressed between patients with and without recurrence. Genes involved in integrin signaling and apoptosis pathways were identified in this gene set. Immortalization-upregulated protein (IMUP), IGF-2, and ARHD had particularly marked differences in expression between patients with and without recurrence.

CONCLUSIONS

Genetic profiling identified genes regulated by chemoradiation including DNA damage and cell-to-cell signaling pathways. Genes associated with recurrence were identified that will require validation in an independent patient data set to determine whether the 58-gene set associated with clinical outcome could be useful as a prognostic assay.

Tumor irradiation increases the recruitment of circulating mesenchymal stem cells into the tumor microenvironment

Mesenchymal stem cells (MSC) migrate to and proliferate within sites of inflammation and tumors as part of the tissue remodeling process. Radiation increases the expression of inflammatory mediators that could enhance the recruitment of MSC into the tumor microenvironment. To investigate this, bilateral murine 4T1 breast carcinomas (expressing renilla luciferase) were irradiated unilaterally (1 or 2 Gy). Twenty-four hours later, 2 x 10(5) MSC-expressing firefly luciferase were injected i.v. Mice were then monitored with bioluminescent imaging for expression of both renilla (tumor) and firefly (MSC) luciferase. Forty-eight hours postirradiation, levels of MSC engraftment were 34% higher in tumors receiving 2 Gy (P = 0.004) than in the contralateral unirradiated limb. Immunohistochemical staining of tumor sections from mice treated unilaterally with 2 Gy revealed higher levels of MSC in the parenchyma of radiated tumors, whereas a higher proportion of MSC remained vasculature-associated in unirradiated tumors. To discern the potential mediators involved in MSC attraction, in vitro migration assays showed a 50% to 80% increase in MSC migration towards conditioned media from 1 to 5 Gy-irradiated 4T1 cells compared with unirradiated 4T1 cells. Irradiated 4T1 cells had increased expression of the cytokines, transforming growth factor-beta1, vascular endothelial growth factor, and platelet-derived growth factor-BB, and this up-regulation was confirmed by immunohistochemistry in tumors irradiated in vivo. Interestingly, the chemokine receptor CCR2 was found to be up-regulated in MSC exposed to irradiated tumor cells and inhibition of CCR2 led to a marked decrease of MSC migration in vitro. In conclusion, clinically relevant low doses of irradiation increase the tropism for and engraftment of MSC in the tumor microenvironment.

Endobronchial Brachytherapy: An Effective Option for Palliation of Malignant Bronchial Obstruction

Symptoms resulting from tumors extending to the endobronchial wall are common in patients with lung cancer and significantly impact quality of life. A number of treatment options are available for palliation, including endobronchial brachytherapy, stent placement, laser photoresection, external-beam radiation therapy, and photodynamic therapy. This review will focus on the methodology and role of endobronchial brachytherapy while discussing benefits of other treatment options as additions or alternatives to brachytherapy.