Mesenchymal Stem Cell-Induced DDR2 Mediates Stromal-Breast Cancer Interactions and Metastasis Growth

Increased collagen deposition by breast cancer (BC)-associated mesenchymal stem/multipotent stromal cells (MSC) promotes metastasis, but the mechanisms are unknown. Here, we report that the collagen receptor discoidin domain receptor 2 (DDR2) is essential for stromal-BC communication. In human BC metastasis, DDR2 is concordantly upregulated in metastatic cancer and multipotent mesenchymal stromal cells. In MSCs isolated from human BC metastasis, DDR2 maintains a fibroblastic phenotype with collagen deposition and induces pathological activation of DDR2 signaling in BC cells. Loss of DDR2 in MSCs impairs their ability to promote DDR2 phosphorylation in BC cells, as well as BC cell alignment, migration, and metastasis. Female ddr2-deficient mice homozygous for the slie mutation show inefficient spontaneous BC metastasis. These results point to a role for mesenchymal stem cell DDR2 in metastasis and suggest a therapeutic approach for metastatic BC.

Abstract P4-03-03: Microenvironment induced DDR2 mediates stromal-cancer interactions and metastasis growth in breast cancer

This abstract was not presented at the symposium.

Abstract 4188: Conditional epithelial cell-specific knockout of CCN6/Wisp3 disrupts normal development of the virgin murine mammary gland

Background: Breast cancer remains one of the top causes of morbidity and mortality among cancer patients in the U.S. Inflammatory breast cancer (IBC) is the most lethal form of locally advanced breast cancer. Our laboratory has shown that CCN6/Wisp3, a secreted extracellular matrix-associated protein which belongs to the CCN family, is lost in 80% of IBC compared to stage-matched non-IBC tumors. We have shown previously that CCN6 knockdown in benign human breast cells leads to an epithelial-to-mesenchymal transition and increased resistance to anoikis. Further, CCN6 overexpression in breast cancer cells reduces invasion and growth in vivo and in vitro. However, the consequences of CCN6 knockout in the mammary gland have never been explored. We hypothesized that the conditional deletion of CCN6 in mammary epithelial cells in mice may lead to defects in mammary gland development and may induce mammary tumors.

Methods: We created a novel transgenic mouse model in which CCN6 is conditionally knocked out in mammary epithelial cells using the Cre-Lox recombination system. We collected groups of CCN6 knockout mice and littermate controls at 8 weeks, 4 months, and 12 months of age to observe the effect of CCN6 knockout on the development of the virgin mammary gland and on de novo tumor formation in aged mice. We also collected groups of CCN6 knockout and control mice at early pregnancy, late pregnancy, lactation and involution timepoints. Mammary whole mounts were prepared in order to characterize the phenotype, and portions of the inguinal gland were collected for immunohistochemical, protein and RNA analysis.

Results: Conditional CCN6 knockout in the murine mammary gland results in defective mammary gland development in pubertal (8-week-old) and post-pubertal (4-month-old) virgin female mice compared to controls. At 8 weeks of age, virgin CCN6 knockout mice exhibit significantly fewer terminal end buds and fewer bifurcated terminal end buds. At 4 months of age, virgin CCN6 knockout mice have fewer lobuloalveolar units and a hypobranching phenotype compared to controls. We observed no phenotypic differences in the pregnancy and lactation timepoints between CCN6 knockout mice and controls, and no differences in pup weight or average litter size, suggesting that CCN6 is not critical for pregnancy and lactation. CCN6 knockout did not lead to spontaneous tumorigenesis in aged mice.

Conclusion: We provide new evidence that CCN6 is an important signaling molecule in the mammary gland in vivo, as CCN6 is necessary for normal mammary development in virginal animals. We are currently analyzing the effects of CCN6 knockout in mammary gland involution after lactation, and the signaling pathways affected by CCN6 knockout in vivo. Further studies are needed to investigate effect of CCN6 knockout in breast cancer in vivo; to this end, we are currently crossing our CCN6 knockout line with the oncogenic MMTV-Pymt transgenic line.

Citation Format: Emily E. Martin, Wei Huang, Jun-Lin Guan, Celina G. Kleer. Conditional epithelial cell-specific knockout of CCN6/Wisp3 disrupts normal development of the virgin murine mammary gland. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4188. doi:10.1158/1538-7445.AM2015-4188

Abstract 5078: Human breast carcinoma-associated mesenchymal stem cells promote breast cancer cell proliferation, irreversible EMT and invasion through Collagen I

Background: Accumulating evidence suggests that mesenchymal stem cells (MSCs) are recruited to the tumor microenvironment and play roles in tumor progression; however their specific mechanisms and functions need further investigation. In this study, we identified the presence of carcinoma-associated MSCs (CA-MSCs) isolated from breast cancer metastasis to a human lymph node (LNM) and liver (LM). We hypothesized that CA-MSCs may increase the invasive abilities of breast cancer cells and that they may enhance collagen expression to promote breast cancer progression.

Methods: We isolated CA-MSCs from fresh samples of breast cancer metastasis to a lymph node and liver obtained from the operating room. A portion of each specimen was subjected to H&E staining to confirm the diagnosis, and another portion was mechanically dissected and digested with collagenase. Red blood cells were lysed with ACK buffer and cell suspensions were cultured in Human Epithelial Medium. Once isolated, adherent CA-MSCs were subcultured in MSC medium for up to 12 passages for each experiment. CA-MSCs were subjected to multilineage differentiation assays (osteogenic, chrodrogenic, and adipogenic differentiation), and labeled with Ds-Red and co-cultured with a panel of breast cancer cells including MDA-MB-231, MCF7, DCIS.COM. We performed RT-PCR, WB, 3D proliferation assays, and invasion assays, and immunoshistochemistry. COAL1 expression was downregulated in the CA-MSCs-DsRED using specific shRNA. Control and CA-MSCs-DsRed-shCOAL1 were co-cultured with MDA-MB-231 and MCF7 breast cancer cells, and subjected to proliferation and invasion assays, and to RT-PCR and WB to investigate EMT proteins.

Results: CA-MSCs had spindle morphology, normal karyotype, were nontumorigenic, and possessed tri-lineage differentiation ability (osteoblast, adipocyte, and chondrocyte). In co-cultures, CA-MSCs promote proliferation, invasion, irreversible EMT through serial passages, compared to single cultures of breast cancer cells. CA-MSCs increased COAL1 expression and collagen 1 deposition in the 3D co-cultures by IHC and RT-PCR. COAL1 shRNA knockdown in CA-MSCs rescued the effect in proliferation and invasion of breast cancer cells in the co-cultures.

Conclusion: We successfully isolated and characterized CA-MSCs, confirming their presence in human breast cancer metastasis. We found that CA-MSCs enhance breast cancer cell proliferation, promote irreversible EMT and invasion and increased COAL1 expression and collagen 1 deposition. We demonstrated that COAL1 expression is required for the effect of CA-MSCs on breast cancer cell proliferation and invasion.

Citation Format: Maria E. Gonzalez, Emily E. Martin, Celina G. Kleer. Human breast carcinoma-associated mesenchymal stem cells promote breast cancer cell proliferation, irreversible EMT and invasion through Collagen I. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5078. doi:10.1158/1538-7445.AM2015-5078

A heuristic approach to edge detection in on-line portal imaging

PURPOSE

Portal field edge detection is an essential component of several postprocessing techniques used in on-line portal imaging, including field shape verification, selective contrast enhancement, and treatment setup error detection. Currently edge detection of successive fractions in a multifraction portal image series involves the repetitive application of the same algorithm. As the number of changes in the field is small compared to the total number of fractions, standard edge detection algorithms essentially recalculate the same field shape numerous times. A heuristic approach to portal edge detection has been developed that takes advantage of the relatively few changes in the portal field shape throughout a fractionation series.

METHODS AND MATERIALS

The routine applies a standard edge detection routine to calculate an initial field edge and saves the edge information. Subsequent fractions are processed by applying an edge detection operator over a small region about each point of the previously defined contour, to determine any shifts in the field shape in the new image. Failure of this edge check indicates that a significant change in the field edge has occurred, and the original edge detection routine is applied to the image. Otherwise the modified edge contour is used to define the new edge.

RESULTS

Two hundred and eighty-one portal images collected from an electronic portal imaging device were processed by the edge detection routine. The algorithm accurately calculated each portal field edge, as well as reducing processing time in subsequent fractions of an individual portal field by a factor of up to 14.

CONCLUSIONS

The heuristic edge detection routine is an accurate and fast method for calculating portal field edges and determining field edge setup errors.

Picture archiving and communications systems in radiation oncology (PACSRO): tools for a physician-based digital image review system

Digital imaging is becoming more and more important in the diagnosis, staging, and treatment of patients in radiation oncology. In order to facilitate the most efficient interface of this technology to physicians and other users of this information, a medical image display system (MID) has been developed at the Fox Chase Cancer Center (FCCC). The system runs on 20 personal computers situated in physicians offices as well as a modified system located in the radiation oncology conference room. Access to CT, MRI, and EPID information is achieved through an Ethernet connection to the hospital picture archiving and communications system (PACS). Over a 1-year period a total of 503 patients and 3845 images have been stored on the system. Physician approval using the MID system (without conventional films) was performed on 106 patients. Of these, 22%, 16%, 11%, 10%, and 9% consisted of breast, prostate, pelvic, lung, and head and neck patients, respectively. Digital images sent from a variety of image sources to the MID system take up to 15 s to process and format while image access and display can take 2-5 s, dependent upon image size and speed of the host computer.

Swallowing function in patients with esophageal cancer treated with concurrent radiation and chemotherapy

BACKGROUND

Major goals of concurrent radiation and chemotherapy in the treatment of esophageal cancer are the early restoration and long-term maintenance of swallowing function. The purpose of this study was to determine the impact of concurrent radiation and chemotherapy on swallowing function.

METHODS

Between September 1980 and September 1990, 120 patients with esophageal cancer were treated at the Fox Chase Cancer Center on the basis of one of three prospective nonrandomized protocols using concurrent chemotherapy and radiation. Swallowing function was retrospectively assessed in these patients by use of a swallowing-function scoring system. In addition, patients who had long-term control of their esophageal cancer underwent a more detailed analysis of swallowing function.

RESULTS

Initial improvement in dysphagia occurred in 88% of the 102 assessable patients, with a median time to improvement of 2 weeks. There was no difference in overall percentage of initial improvement for patients with adenocarcinoma versus squamous cell carcinoma. Patients with distal tumors, however, showed both earlier and higher frequency of initial improvement than did patients with tumors in the upper two-thirds of the thoracic esophagus (95% versus 79%). Local relapse-free survival of definitively treated patients at 3 years was 60% and was significantly better for patients with Stage I (76%) versus Stage II cancers (55%) (P < 0.05). All 25 patients treated with curative intent who survived for more than 1 year without evidence of disease were able to eat soft or solid foods and had a benign stricture rate of only 12%. Even in patients with advanced disease who were treated with palliative intent, 91% had an initial improvement in swallowing function and 67% had improvement in swallowing function that lasted until death.

CONCLUSIONS

High-dose concurrent radiation and chemotherapy provides rapid improvement in dysphagia, and this improvement results in normal or near-normal swallowing function of long duration.

Digital imaging in the radiation oncology environment: a personal computer local area network solution

Personal computer (PC) driven digital imaging devices are now becoming available in the market place for use in radiation oncology to produce what are known as real time portal images. These limited contrast images are used to verify the patient anatomy under treatment by megavoltage x-rays and are a vital part of the patient treatment. The current generation of devices can produce both single and movie loop images in real time for physician review and approval. To disseminate these images and other digital images used in the planning and delivery of radiation therapy, a PC-based picture archiving and communications system has been developed that is tailored to the special needs of radiation oncology.

Human T helper cells specific for antigens of typhus group rickettsiae enhance natural killer cell activity in vitro

The peripheral blood mononuclear cells (PBMC) from 5 individuals immune to typhus group rickettsiae and from 13 nonimmune individuals were stimulated in vitro for 7 days with typhus group rickettsial antigen (TGRA). At the end of day 7, lysis of the natural killer (NK)-susceptible target K562 by these PBMC was determined. As controls, PBMC from both groups of donors were cultured in vitro for 7 days without antigen or were freshly isolated, and lysis of the K562 target was determined. There was no significant difference between the level of NK activity in freshly isolated PBMC from immune and nonimmune donors. PBMC from immune donors which were stimulated with antigen for 7 days exhibited significantly greater NK activity than did the control population, which was cultured for 7 days without antigen. PBMC from immune donors which were stimulated with TGRA demonstrated significantly higher NK activity than the same PBMC stimulated with antigen derived from an antigenically unrelated rickettsia, Coxiella burnetii. There was no significant difference, however, in the level of NK activity of nonimmune antigen-stimulated PBMC compared with that of the same PBMC population cultured without antigen. Most of the antigen-stimulated NK activity was mediated by Leu-11-positive cells as determined by electronic cell sorting. The ability of TGRA to sustain the NK activity of PBMC from immune donors was abolished when the T4/Leu-3-positive population of lymphocytes was eliminated by positive or negative selection prior to antigen stimulation. The ability of TGRA to sustain the NK activity of PBMC from immune donors was also significantly decreased in the presence of antibodies against human interleukin-2. The results suggest that the activity of human NK cells can be sustained in vitro by antigen-specific T helper cells and that the effect of the T helper cell is mediated, at least in part, by interleukin-2.

Determination of Sulfamethazine in Mixed Feeds Containing Procaine Penicillin

Sulfamethazine in combination with procaine penicillin is used as a medicament in swine feeds. Interference from procaine must be eliminated to determine sulfamethazine by the Bratton-Marshall color reaction. In the method, sulfamethazine is extracted with hot methanol, the protein is precipitated with zinc sulfate and filtered, and the azo dyes of sulfamethazine and procaine are formed by the Bratton-Marshall color reaction. The mixed dye solution is shaken with chloroform to separate the procaine dye, made alkaline, and reshaken. An aliquot of the aqueous phase which contains the sulfamethazine dye is removed, re-acidified, and measured at 540 mμ.i against a standard curve. Procaine penicillin added at 25 times the formulation level does not interfere. Swine feeds at sulfamethazine levels of 0.011 and 0.044% give average recoveries of 95 and 99%, respectively, with a coefficient of variation of less than 6% under routine laboratory conditions.

Determination of Dienestrol Diacetate in Mixed Feeds

Dienestrol diacetate in broiler feeds is isolated by extraction followed by alkaline hydrolysis to yield the parent phenolic compound. Interferences are removed by partition between NaOH and chloroform, in a manner similar to the AOAC procedure for diethylstilbestrol. The dienestrol is acidified, extracted with chloroform, and measured spectrophotometrically at 610 mμ after reaction with anisaldehyde. Recovery of dienestrol diacetate from 4 feeds known to contain 23–92 ppm ranged from 93 to 107% with coefficients of variation of 7.0–16.4%. Values for blank feeds were low enough to exclude a feed blank from the analytical procedure. Amounts of colorimetric reagents, reaction time, and linearity of response were studied. Of 24 common medicaments and 6 solvents tested, only acetone interferes.