A functional heparan sulfate mimetic implicates both heparanase and heparan sulfate in tumor angiogenesis and invasion in a mouse model of multistage cancer

Heparan sulfate proteoglycans are integral components of the extracellular matrix that surrounds all mammalian cells. In addition to providing structural integrity, they act as a storage depot for a variety of heparan sulfate (HS)-binding proteins, including growth factors and chemokines. Heparanase is a matrix-degrading enzyme that cleaves heparan sulfate side chains from the core proteoglycans, thus liberating such HS-binding proteins, as well as potentially contributing to extracellular matrix degradation. Here, we report that heparanase mRNA and protein expression are increased in the neoplastic stages progressively unfolding in a mouse model of multistage pancreatic islet carcinogenesis. Notably, heparanase is delivered to the neoplastic lesions in large part by infiltrating Gr1+/Mac1+ innate immune cells. A sulfated oligosaccharide mimetic of heparan sulfate, PI-88, was used to inhibit simultaneously both heparanase activity and HS effector functions. PI-88 had significant effects at distinct stages of tumorigenesis, producing a reduction in the number of early progenitor lesions and an impairment of tumor growth at later stages. These responses were associated with decreased cell proliferation, increased apoptosis, impaired angiogenesis, and a substantive reduction in the number of invasive carcinomas. In addition, we show that the reduction in tumor angiogenesis is correlated with a reduced association of VEGF-A with its receptor VEGF-R2 on the tumor endothelium, implicating heparanase in the mobilization of matrix-associated VEGF. These data encourage clinical applications of inhibitors such as PI-88 for the many human cancers where heparanase expression is elevated or mobilization of HS-binding regulatory factors is implicated.     

Potential of endogenous estrogen receptor beta to influence the selective ER modulator ERbeta complex

The ratio of estrogen receptor beta (ERbeta) to ERalpha can alter the estrogen-like properties of tamoxifen. Transient transfection of ERbeta cDNA into cells can decrease the estrogen-like properties of the ERalpha:tamoxifen complex, whereas an increase in the amount of ERbeta is associated with tamoxifen-resistant breast cancer. We have addressed each of these hypotheses by examining well characterized laboratory models. We determined whether changes in endogenous ERbeta are responsible for the estrogen-like or antiestrogenic properties of tamoxifen or raloxifene in MDA-MB-231 cells transfected with cDNAs for ERalpha or mutants D351G, D351Y. We found that the amount of ERbeta mRNA in separate, stable transfectants of mutant ERalpha cDNA was always < 2% of ERalpha. Since at least a 50:50 mixture of ERalpha:ERbeta is needed to silence the tamoxifen:ERalpha complex, we conclude that insufficient ERbeta mRNA is available for selective ER modulation in stable transfectants of D351G and D351Y ERalpha. Similarly, to test the hypothesis that ERbeta is up-regulated and plays an important role during the development of tamoxifen-stimulated tumor growth, we quantitatively analyzed ERbeta and ERalpha mRNA in tamoxifen-na?ve (MCF-7:E2, ECC1:E2) and tamoxifen-stimulated tumors (MCF-7:TAM, EnCa 101:TAM). We found that ERbeta mRNA levels were not significantly elevated in tamoxifen-stimulated tumors and the ERalpha mRNA remained over 99% out of all ER species for all the tumors tested. The same results were also obtained when mRNA levels of ERbeta and ERalpha in a series of tamoxifen-na?ve and tamoxifen-resistant breast cancer was analyzed. We conclude that endogenous ERbeta may not play a dominant role in the modulation of the tamoxifen ERalpha complex, or in the development of tamoxifen-stimulated resistant tumor growth.     

R-CHOP-14 in patients with diffuse large B-cell lymphoma: feasibility and preliminary efficacy

Treatment of diffuse large B-cell lymphoma (DLBCL) with CHOP-21 (cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, vincristine 1.4 mg/m2, prednisone 100 mg for 5 days every 21 days) results in long-term remission in approximately 45% of patients. Recent phase III trials have demonstrated improved survival by modifying CHOP either through adding rituximab or shortening the time between cycles to 14 days. These studies prompted our institution to treat newly diagnosed patients with DLBCL refusing or not eligible for protocol-based therapy with R-CHOP-14. In this single-institution retrospective analysis, we report our results with this regimen. Forty-nine patients with newly diagnosed DLBCL and ineligible or refusing protocol-based therapy were retrospectively identified. Patients were treated with 6-8 cycles of R-CHOP-14 given with filgrastim and prophylactic antibiotics. The main toxicities with R-CHOP-14 were hematological and neurological and were not unexpected. There were no treatment-related deaths. Patients received 90% of planned cytotoxic drug density. The complete remission/complete remission uncertain (CR/CRu) rate was 82.2%. At a median follow-up of 24 months, the event-free survival was 80% and overall survival 90%. These results demonstrate R-CHOP-14 can be given to patients safely and short-term results regarding survival are promising. Whether adding rituximab and increasing dose intensity improves survival over either alone will require randomized studies.