Chemokine CXCL12 and receptor CXCR4 control multiple steps in primary tumor growth and metastasis in breast cancer and more than 20 other human malignancies. Mechanisms that regulate availability of CXCL12 in tumor microenvironments will substantially impact cancer progression and ongoing efforts to target the CXCL12-CXCR4 pathway for cancer chemotherapy. We used dual luciferase imaging to investigate CXCR7 dependent scavenging of CXCL12 in breast tumors in vivo and quantify effects of CXCR7 on tumor growth and metastasis of a separate population of CXCR4+ breast cancer cells. In a mouse xenograft model of human breast cancer, in vivo imaging showed that malignant cells expressing CXCR7 reduced bioluminescent CXCL12 secreted in the primary tumor microenvironment. Capitalizing on sensitive detection of bioluminescent CXCL12, we also demonstrated that CXCR7+ cells reduced amounts of chemokine released from orthotopic tumors into the circulation. Immunofluorescence staining of human primary breast cancers showed expression of CXCR4 and CXCR7 on malignant cells in ≈ 30% of cases. In most cases, CXCR4 and CXCR7 predominantly were expressed on separate populations of malignant cells in a tumor. We modeled these cases of human breast cancer by co-implanting tumor xenografts with CXCR4+ breast cancer cells, human mammary fibroblasts secreting CXCL12, and CXCR7+ or control breast cancer cells. Bioluminescence imaging showed that CXCR7+ breast cancer cells enhanced proliferation of CXCR4+ breast cancer cells in orthotopic tumors and spontaneous metastases. Treatment with a small molecule inhibitor of CXCR7 chemokine scavenging limited growth of CXCR4+ breast cancer cells in tumors that also contained malignant CXCR7+ cells. These studies establish a new in vivo imaging method to quantify chemokine scavenging by CXCR7 in the tumor microenvironment and identify that CXCR7+ cells promote growth and metastasis of CXCR4+ breast cancer cells.

Fluorescent proteins with emission wavelengths in the near-infrared and infrared range are in high demand for whole-body imaging techniques. We report near-infrared fluorescent proteins eqFP650 and eqFP670. To our knowledge, eqFP650 is the brightest fluorescent protein with emission maximum above 635 nm, and eqFP670 displays the most red-shifted emission maximum and high photostability.

Studies of ligand-receptor binding and development of receptor antagonists would benefit greatly from imaging techniques that translate directly from cell-based assays to living animals. We used Gaussia luciferase protein fragment complementation to quantify binding of chemokine CXCL12 to receptors CXCR4 and CXCR7. Small molecule inhibitors of CXCR4 or CXCR7 specifically blocked CXCL12 binding in cell-based assays, and these studies revealed differences in kinetics for inhibiting chemokine binding to each receptor. Bioluminescence imaging showed CXCL12-CXCR7 binding in primary and metastatic tumors in a mouse model of breast cancer. We also used this imaging technique to quantify drug-mediated inhibition of CXCL12-CXCR4 binding in living mice. We expect this imaging technology to advance research in areas including ligand-receptor interactions and development of new therapeutic agents in cell-based assays and small animals.

From 1976 to 1995, 23 children, 4 boys and 19 girls, were treated at our department for sacrococcygeal teratomas (SCT). Their records were analyzed retrospectively, considering age at operation, histopathology, recurrences, and long-term evolution. One died on the 1st day of life following tumor rupture with hemorrhagic shock without surgical intervention. All others were operated upon at a mean age of 4.2 days for those 19 (= 82%) who were diagnosed in the neonatal period and whose histology proved benign. In the remaining 3 children, in whom tumor manifestation did not occur before 11 months, 13 months, and 10 years of age, respectively, histopathologic evaluation revealed 2 carcinomas and 1 yolk-sac tumor, and all 3 recurred. Overall, 5 patients died, the 1 mentioned above, 1 due to volvulus after laparotomy, and 1 from multiple associated congenital malformations. Two deaths were related to malignancy, whereby only 1 was a malignant teratoma diagnosed at the original operation. Eight children had recurrences, 2 were benign and 6 malignant, with 3 of the latter having been graded benign on histology of the primary tumor. Of the 18 surviving patients, 17 (93.5%) returned for clinical review following a standardized protocol. The average interval from the primary surgery was 12.3 years (range 3.5-22 years). Four had malignant tumors with a recurrence-free period of from 9 to 14 years; 5 (29.4%) had urinary or anorectal functional impairment. One child with a patulous anus presented with fecal soiling. Two reported nocturnal enuresis, 1 associated with perineal anesthesia. One had a neurogenic bladder with overflow voiding and bilateral third-degree vesicoureteral reflux. Second-degree reflux was found in the last patient. We conclude that follow-up after surgery for SCT should not only search for tumor recurrence but include the diagnosis and treatment of possible secondary urinary and/or fecal incontinence.

Patients with metastatic ovarian cancer continue to have a dismal prognosis, emphasizing the need for new strategies to identify and develop new molecular targets for therapy. Chemokine CXCL12 and its receptor CXCR4 are upregulated in metastatic ovarian cancer cells and the intraperitoneal tumor microenvironment. CXCL12-CXCR4 signaling promotes multiple steps in proliferation and dissemination of ovarian cancer cells, suggesting that targeted inhibition of this pathway will limit tumor progression. To investigate CXCL12-CXCR4 signaling in ovarian cancer and establish effects of inhibiting this pathway on tumor progression and survival, we designed a Gaussia luciferase complementation imaging reporter system to detect CXCL12 binding to CXCR4 in ovarian cancer cells. In cell-based assays, we established that the complementation imaging reporter could detect CXCL12 binding to CXCR4 and quantify specific inhibition of ligand-receptor interaction. We monitored CXCL12-CXCR4 binding and inhibition in a mouse xenograft model of metastatic human ovarian cancer by imaging Gaussia luciferase complementation and assessed tumor progression with firefly luciferase. Bioluminescence imaging studies in living mice showed that treatment with AMD3100, a clinically approved inhibitor of CXCL12-CXCR4, blocked ligand-receptor binding and reduced growth of ovarian cancer cells. Treatment with AMD3100 also modestly improved overall survival of mice with metastatic ovarian cancer. The Gaussia luciferase complementation imaging reporter system will facilitate further preclinical development and optimization of CXCL12-CXCR4 targeted compounds for treatment of ovarian cancer. Our research supports clinical translation of existing CXCR4 inhibitors for molecular therapy for ovarian cancer.