Multifocal Gastric Ulcers Caused by Diffuse Large B Cell Lymphoma in a Patient With Significant Weight Loss

Primary gastrointestinal (GI) lymphoma is a heterogeneous disease with varied clinical presentations. The stomach is the most common GI site and accounts for 70% to 75% of GI lymphomas. We present a patient with gastric diffuse large B cell lymphoma (DLBCL) who presented with significant weight loss, early satiety, and multifocal ulcerated gastric lesions. Esophagoduodenoscopy should be performed in patients presenting with warning symptoms as in our case. Diagnosis is usually made by endoscopic biopsies. Multiple treatment modalities including surgery, radiotherapy, and chemotherapy have been used. Advancements in endoscopic and pathologic technology decrease turnaround time for diagnosis and treatment initiation, thus reducing the need for surgery. Health care providers should maintain a high level of suspicion and consider gastric DLBCL as part of the differential diagnosis, especially in those with warning symptoms such as weight loss and early satiety with abnormal endoscopic findings

Tumor-expressed adrenomedullin accelerates breast cancer bone metastasis

INTRODUCTION: Adrenomedullin (AM) is secreted by breast cancer cells and increased by hypoxia. It is a multifunctional peptide that stimulates angiogenesis and proliferation. The peptide is also a potent paracrine stimulator of osteoblasts and bone formation, suggesting a role in skeletal metastases-a major site of treatment-refractory tumor growth in patients with advanced disease. METHODS: The role of adrenomedullin in bone metastases was tested by stable overexpression in MDA-MB-231 breast cancer cells, which cause osteolytic bone metastases in a standard animal model. Cells with fivefold increased expression of AM were characterized in vitro, inoculated into immunodeficient mice and compared for their ability to form bone metastases versus control subclones. Bone destruction was monitored by X-ray, and tumor burden and osteoclast numbers were determined by quantitative histomorphometry. The effects of AM overexpression on tumor growth and angiogenesis in the mammary fat pad were determined. The effects of AM peptide on osteoclast-like multinucleated cell formation were tested in vitro. A small-molecule AM antagonist was tested for its effects on AM-stimulated ex vivo bone cell cultures and co-cultures with tumor cells, where responses of tumor and bone were distinguished by species-specific real-time PCR. RESULTS: Overexpression of AM mRNA did not alter cell proliferation in vitro, expression of tumor-secreted factors or cell cycle progression. AM-overexpressing cells caused osteolytic bone metastases to develop more rapidly, which was accompanied by decreased survival. In the mammary fat pad, tumors grew more rapidly with unchanged blood vessel formation. Tumor growth in the bone was also more rapid, and osteoclasts were increased. AM peptide potently stimulated bone cultures ex vivo; responses that were blocked by small-molecule adrenomedullin antagonists in the absence of cellular toxicity. Antagonist treatment dramatically suppressed tumor growth in bone and decreased markers of osteoclast activity. CONCLUSIONS: The results identify AM as a target for therapeutic intervention against bone metastases. Adrenomedullin potentiates osteolytic responses in bone to metastatic breast cancer cells. Small-molecule antagonists can effectively block bone-mediated responses to tumor-secreted adrenomedullin, and such agents warrant development for testing in vivo

Cell adhesion molecule CD166 drives malignant progression and osteolytic disease in multiple myeloma

Multiple myeloma (MM) is incurable once osteolytic lesions have seeded at skeletal sites, but factors mediating this deadly pathogenic advance remain poorly understood. Here we report evidence of a major role for the cell adhesion molecule CD166, which we discovered to be highly expressed in MM cell lines and primary bone marrow (BM) cells from patients. CD166+ MM cells homed more efficiently than CD166− cells to the BM of engrafted immunodeficient NSG mice. CD166 silencing in MM cells enabled longer survival, a smaller tumor burden and less osteolytic lesions, as compared to mice bearing control cells. CD166 deficiency in MM cell lines or CD138+ BM cells from MM patients compromised their ability to induce bone resorption in an ex vivo organ culture system. Further, CD166 deficiency in MM cells also reduced formation of osteolytic disease in vivo after intra-tibial engraftment. Mechanistic investigation revealed that CD166 expression in MM cells inhibited osteoblastogenesis of BM-derived osteoblast progenitors by suppressing RUNX2 gene expression. Conversely, CD166 expression in MM cells promoted osteoclastogenesis by activating TRAF6-dependent signaling pathways in osteoclast progenitors. Overall, our results define CD166 as a pivotal director in MM cell homing to the BM and MM progression, rationalizing its further study as a candidate therapeutic target for MM treatment

FGF23 is elevated in multiple myeloma and increases heparanase expression by tumor cells

Multiply myeloma (MM) grows in and destroys bone, where osteocytes secrete FGF23, a hormone which affects phosphate homeostasis and aging. We report that multiple myeloma (MM) cells express receptors for and respond to FGF23. FGF23 increased mRNA for EGR1 and its target heparanase, a pro-osteolytic factor in MM. FGF23 signals through a complex of klotho and a classical FGF receptor (FGFR); both were expressed by MM cell lines and patient samples. Bone marrow plasma cells from 42 MM patients stained positively for klotho, while plasma cells from 8 patients with monoclonal gammopathy of undetermined significance (MGUS) and 6 controls were negative. Intact, active FGF23 was increased 2.9X in sera of MM patients compared to controls. FGF23 was not expressed by human MM cells, but co-culture with mouse bone increased its mRNA. The FGFR inhibitor NVP-BGJ398 blocked the heparanase response to FGF23. NVP-BGJ398 did not inhibit 8226 growth in vitro but significantly suppressed growth in bone and induction of the osteoclast regulator RANK ligand, while decreasing heparanase mRNA. The bone microenvironment provides resistance to some anti-tumor drugs but increased the activity of NVP-BGJ398 against 8226 cells. The FGF23/klotho/heparanase signaling axis may offer targets for treatment of MM in bone

ROLE OF CD166 IN MULTIPLE MYELOMA CELL HOMING TO THE BONE MARROW MICROENVIRONMENT AND DISEASE PROGRESSION

poster abstractMultiple myeloma (MM) is a plasma cell malignancy characterized by multiple lytic lesions throughout the skeleton, suggesting that trafficking of MM cells from the bone marrow (BM) and lodgment of these cells at secondary sites is important in disease progression. CD38+CD138- MM cells were previously characterized as putative MM stem cells (MMSC, Cancer Res. 2008; 68(1):190-7.). We analyzed CD38+CD138- cells contained within the MM cell line H929 and determined that a fraction of these cells (29.9%±1.4%) expresses CD166. CD166 is a member of the immunoglobulin superfamily capable of mediating both homophilic and heterophilic (CD6) interactions and has been shown to enhance metastasis and invasion in several tumors including breast cancer and melanoma. Studies from our laboratory suggest that CD38+CD138-CD166+ MM cells possess many functional properties commonly associated with MMSC including cell cycle quiescence, maintenance and propagation of daughter cells on a stromal substrate and gene expression profile. We hypothesized that CD166 promotes MM cell trafficking to the BM and is critical for disease progression. To test this hypothesis, H929-GFP myeloma cells were injected intravenously into NSG mice and GFP cells were recovered from the BM 14hr later. While only 3.3%±1.5% of total H929-GFP cells express the CD38+CD138- phenotype, the frequency of CD38+CD138- cells contained in BM-homed H929-GFP cells was significantly higher (53.4%±3.7%, n=3, p<0.01), suggesting a preferential homing of MMSC to the marrow microenvironment. Interestingly, whereas only 29.9%±1.4% of CD38+CD138- cells expressed CD166 prior to injection, 84.1%±10.8% of BM-homed H929-GFP CD38+CD138- cells expressed CD166 (n=3, p<0.01), suggesting that CD166 plays a critical role in directing homing of MM cells to the BM. Next, CD166 expression on H929-GFP cells was knocked down (KD) with shRNA in order to examine if reduced CD166 expression inhibit the homing of MM cells to the BM. The number of BM-homed GFP cells was significantly decreased for CD166KD cells (5658±904, n=6) compared to mock control (8551±848, n=6; p<0.05). Interestingly, cells in which suppression of CD166 expression was not achieved with shRNA homed preferentially to the BM (4.3%±0.3% CD166+cells in CD166 KD H929-GFP before injection versus 29.3%±3.6% in BM-homed GFP cells). Then we compared the progression of MM in NSG mice initiated with mock control or CD166 KD H929-GFP cells. Disease progression in mice receiving control cells was more rapid compared to that in mice receiving CD166KD cells as evidenced by serum levels of human IgA (kappa) at 4 weeks posttransplantation (240.5±67.1ng/ml versus 45.1±33.0ng/ml, n=3; p<0.05). We next examined the potential role of CD166 in osteolytic lesions using a novel Ex Vivo Organ Culture Assay (EVOCA) in which MM cells are co-cultured over calvariae from 10d-old pups for 7 days creating an in vitro 3D system for the interaction of MM cells with bone microenvironment. Data from EVOCA with H929 cells showed that bone osteolytic lesions are substantially reduced when CD166 is absent on either MM (CD166- fraction) or osteoblast lineage cells (calvariae from CD166-/- mice). Furthermore, co-culturing CD166+ or CD166- H929 cells with bone marrow stromal cells (BMSC) from WT or CD166-/- mice revealed that mRNA levels of receptor activator of NF-κB ligand (RANKL) are decreased when CD166 is absent on either MM or stromal cells while mRNA levels of osteoprotegerin (OPG), an important inhibitor of osteoclastogenesis, are not altered. This resulted in decreased RANKL/OPG ratios in cultures containing a CD166- component suggesting reduced MM-induced osteoclastogenesis in the absence of CD166. Interestingly, levels of M-CSF and IL-6 were similar in all these cultures suggesting that loss of CD166 may mediate suppression of osteolytic lesions through the downregulation of RANKL. Together, these results suggest that CD166 plays an important role in homing and retention of MM cells in the BM and promotes MM disease progression as well as bone-lytic disease and that CD166 may serve as a therapeutic target in the treatment of MM

CD34-related coexpression of MDR1 and BCRP indicates a clinically resistant phenotype in patients with acute myeloid leukemia (AML) of older age

Clinical resistance to chemotherapy in acute myeloid leukemia (AML) is associated with the expression of the multidrug resistance (MDR) proteins P-glycoprotein, encoded by the MDR1/ABCB1 gene, multidrug resistant-related protein (MRP/ABCC1), the lung resistance-related protein (LRP), or major vault protein (MVP), and the breast cancer resistance protein (BCRP/ABCG2). The clinical value of MDR1, MRP1, LRP/MVP, and BCRP messenger RNA (mRNA) expression was prospectively studied in 154 newly diagnosed AML patients ≥60 years who were treated in a multicenter, randomized phase 3 trial. Expression of MDR1 and BCRP showed a negative whereas MRP1 and LRP showed a positive correlation with high white blood cell count (respectively, p < 0.05, p < 0.001, p < 0.001 and p < 0.001). Higher BCRP mRNA was associated with secondary AML (p < 0.05). MDR1 and BCRP mRNA were highly significantly associated (p < 0.001), as were MRP1 and LRP mRNA (p < 0.001) expression. Univariate regression analyses revealed that CD34 expression, increasing MDR1 mRNA as well as MDR1/BCRP coexpression, were associated with a lower complete response (CR) rate and with worse event-free survival and overall survival. When adjusted for other prognostic actors, only CD34-related MDR1/BCRP coexpression remained significantly associated with a lower CR rate (p = 0.03), thereby identifying a clinically resistant subgroup of elderly AML patients

Multifocal Gastric Ulcers Caused by Diffuse Large B Cell Lymphoma in a Patient With Significant Weight Loss

Primary gastrointestinal (GI) lymphoma is a heterogeneous disease with varied clinical presentations. The stomach is the most common GI site and accounts for 70% to 75% of GI lymphomas. We present a patient with gastric diffuse large B cell lymphoma (DLBCL) who presented with significant weight loss, early satiety, and multifocal ulcerated gastric lesions. Esophagoduodenoscopy should be performed in patients presenting with warning symptoms as in our case. Diagnosis is usually made by endoscopic biopsies. Multiple treatment modalities including surgery, radiotherapy, and chemotherapy have been used. Advancements in endoscopic and pathologic technology decrease turnaround time for diagnosis and treatment initiation, thus reducing the need for surgery. Health care providers should maintain a high level of suspicion and consider gastric DLBCL as part of the differential diagnosis, especially in those with warning symptoms such as weight loss and early satiety with abnormal endoscopic findings

Identifying novel mechanisms of biallelic TP53 loss refines poor outcome for patients with multiple myeloma

Abstract Biallelic TP53 inactivation is the most important high-risk factor associated with poor survival in multiple myeloma. Classical biallelic TP53 inactivation has been defined as simultaneous mutation and copy number loss in most studies; however, numerous studies have demonstrated that other factors could lead to the inactivation of TP53. Here, we hypothesized that novel biallelic TP53 inactivated samples existed in the multiple myeloma population. A random forest regression model that exploited an expression signature of 16 differentially expressed genes between classical biallelic TP53 and TP53 wild-type samples was subsequently established and used to identify novel biallelic TP53 samples from monoallelic TP53 groups. The model reflected high accuracy and robust performance in newly diagnosed relapsed and refractory populations. Patient survival of classical and novel biallelic TP53 samples was consistently much worse than those with mono-allelic or wild-type TP53 status. We also demonstrated that some predicted biallelic TP53 samples simultaneously had copy number loss and aberrant splicing, resulting in overexpression of high-risk transcript variants, leading to biallelic inactivation. We discovered that splice site mutation and overexpression of the splicing factor MED18 were reasons for aberrant splicing. Taken together, our study unveiled the complex transcriptome of TP53, some of which might benefit future studies targeting abnormal TP53