The HMGA1-COX-2 axis: a key molecular pathway and potential target in pancreatic adenocarcinoma.

CONTEXT: Although pancreatic cancer is a common, highly lethal malignancy, the molecular events that enable precursor lesions to become invasive carcinoma remain unclear. We previously reported that the high-mobility group A1 (HMGA1) protein is overexpressed in >90% of primary pancreatic cancers, with absent or low levels in early precursor lesions. METHODS: Here, we investigate the role of HMGA1 in reprogramming pancreatic epithelium into invasive cancer cells. We assessed oncogenic properties induced by HMGA1 in non-transformed pancreatic epithelial cells expressing activated K-RAS. We also explored the HMGA1-cyclooxygenase (COX-2) pathway in human pancreatic cancer cells and the therapeutic effects of COX-2 inhibitors in xenograft tumorigenesis. RESULTS: HMGA1 cooperates with activated K-RAS to induce migration, invasion, and anchorage-independent cell growth in a cell line derived from normal human pancreatic epithelium. Moreover, HMGA1 and COX-2 expression are positively correlated in pancreatic cancer cell lines (r(2) = 0.93; p < 0.001). HMGA1 binds directly to the COX-2 promoter at an AT-rich region in vivo in three pancreatic cancer cell lines. In addition, HMGA1 induces COX-2 expression in pancreatic epithelial cells, while knock-down of HMGA1 results in repression of COX-2 in pancreatic cancer cells. Strikingly, we also discovered that Sulindac (a COX-1/COX-2 inhibitor) or Celecoxib (a more specific COX-2 inhibitor) block xenograft tumorigenesis from pancreatic cancer cells expressing high levels of HMGA1. CONCLUSIONS: Our studies identify for the first time an important role for the HMGA1-COX-2 pathway in pancreatic cancer and suggest that targeting this pathway could be effective to treat, or even prevent, pancreatic cancer.

Low dose, oral epsilon aminocaproic acid for renal papillary necrosis and massive hemorrhage in hemoglobin SC disease.

Renal papillary necrosis in sickling hemoglobinopathies can lead to significant complications, including hemorrhage, obstruction, and infection. Despite its frequency, there are limited therapies for protracted hemorrhage. In the past, massive hemorrhage was managed with nephrectomy. Here, we report a patient with hemoglobin SC disease and prolonged, life-threatening hemorrhage from papillary necrosis successfully treated with oral, low-dose epsilon aminocaproic acid (EACA). Although further study is warranted, this case illustrates the need to consider EACA in the conservative management of renal papillary necrosis and significant hemorrhage in sickle cell hemoglobinopathies.

Cyclooxygenase inhibitors block uterine tumorigenesis in HMGA1a transgenic mice and human xenografts.

Uterine cancer is a common cause for cancer death in women and there is no effective therapy for metastatic disease. Thus, research is urgently needed to identify new therapeutic agents. We showed previously that all female HMGA1a transgenic mice develop malignant uterine tumors, indicating that HMGA1a causes uterine cancer in vivo. We also demonstrated that HMGA1a up-regulates cyclooxygenase-2 (COX-2) during tumorigenesis in this model. Similarly, we found that HMGA1a and COX-2 are overexpressed in human leiomyosarcomas, a highly malignant uterine cancer. Although epidemiologic studies indicate that individuals who take COX inhibitors have a lower incidence of some tumors, these inhibitors have not been evaluated in uterine cancer. Here, we show that HMGA1a mice on sulindac (a COX-1/COX-2 inhibitor) have significantly smaller uterine tumors than controls. To determine if COX inhibitors are active in human uterine cancers that overexpress HMGA1a, we treated cultured cells with sulindac sulfide or celecoxib (a specific COX-2 inhibitor). Both drugs block anchorage-independent growth in high-grade human uterine cancer cells that overexpress HMGA1a (MES-SA cells). In contrast, neither inhibitor blocked transformation in cells that do not overexpress HMGA1a. Moreover, xenograft tumors from MES-SA cells were significantly inhibited in mice on sulindac. More strikingly, no tumors formed in mice on celecoxib. These preclinical studies suggest that COX inhibitors could play a role in preventing tumor onset or progression in uterine cancers with dysregulation of the HMGA1a-COX-2 pathway. Importantly, these drugs have lower toxicity than chemotherapeutic agents used to treat advanced-stage uterine cancers.

More common than you think: common variable immune deficiency.

We report a challenging case of a 16-year-old male who presented with thrombocytopenia and eluded a definitive diagnosis for over 2 years. He was initially diagnosed with a viral illness, although he later developed adenopathy and splenomegaly. An evaluation by an oncologist was unrevealing. He worked on a farm with livestock exposure and was later diagnosed with an atypical, zoonotic infection. Despite appropriate antibiotic therapy, the thrombocytopenia and splenomegaly persisted. Further evaluation revealed that he has a relatively common immunologic disorder. He is currently doing well on appropriate therapy for this disorder.