Treatment with TDF and PI/r was associated with greater declines in renal function over 48 weeks compared with TDF+NNRTI-based regimens.
The anticancer potency of green tea and its individual components is being intensely investigated, and some cancer patients already self-medicate with this "miracle herb" in hopes of augmenting the anticancer outcome of their chemotherapy. Bortezomib (BZM) is a proteasome inhibitor in clinical use for multiple myeloma. Here, we investigated whether the combination of these compounds would yield increased antitumor efficacy in multiple myeloma and glioblastoma cell lines in vitro and in vivo. Unexpectedly, we discovered that various green tea constituents, in particular (-)-epigallocatechin gallate (EGCG) and other polyphenols with 1,2-benzenediol moieties, effectively prevented tumor cell death induced by BZM in vitro and in vivo. This pronounced antagonistic function of EGCG was evident only with boronic acid-based proteasome inhibitors (BZM, MG-262, PS-IX), but not with several nonboronic acid proteasome inhibitors (MG-132, PS-I, nelfinavir). EGCG directly reacted with BZM and blocked its proteasome inhibitory function; as a consequence, BZM could not trigger endoplasmic reticulum stress or caspase-7 activation, and did not induce tumor cell death. Taken together, our results indicate that green tea polyphenols may have the potential to negate the therapeutic efficacy of BZM and suggest that consumption of green tea products may be contraindicated during cancer therapy with BZM. (Blood. 2009;113:5927-5937) IntroductionHerbal supplements are commonly perceived as "innocent" or "holistic" and have become hugely popular as unrestrictedly available, over-the-counter, cure-all remedies. Cancer patients in particular may be tempted to self-medicate with such supplements in hopes to delay the progression of their disease and/or reduce the side effects associated with conventional chemotherapy, 1-3 and they may do this unbeknownst to their health care providers. 2,3 One very popular herb is green tea, brewed from the leaves of the plant Camellia sinensis, which appears to be an ideal alternative medicine because it is nontoxic and shown to have cardioprotective, neuroprotective, anti-infective, and antitumoral properties. [4][5][6][7][8][9][10] Green tea products are also available as highly concentrated extracts, which can be easily accessed by the public at local grocery, pharmacy, and health food stores throughout the United States.Green tea is a heterogeneous product that contains several antioxidant compounds, known as polyphenols. (-)-Epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallate catechin (EGC), and (-)-epicatechin (EC) are some of the polyphenol compounds found in green tea. 9 EGCG, the most bioactive green tea polyphenol, was demonstrated to be a multipotent chemopreventive and anticancer agent in several animal models, including leukemia, lung, prostate, colon, and breast cancer. 9,[11][12][13][14][15] It was shown to interact with numerous protein targets and to disrupt biologic/biochemical reactions involved in cancer progression. The EGCG compound can vary its chemical conf...
Patients with HIV and viral hepatitis had greater liver mortality than patients with HIV alone, but had comparable HIV mortality. Co-infection with hepatitis B is associated with hepatic outcomes similar to hepatitis C. Control of immunosuppression with HAART and CD4 counts > 200 x 10(6) cells/l are associated with better hepatic outcomes and should be the first priority in patients with HIV and viral hepatitis.
Obesity is associated with increased cancer incidence and mortality. We have previously found that obesity in children is associated with a 50% increased recurrence of acute lymphoblastic leukemia (ALL) in high-risk patients. We have therefore developed novel in vivo and in vitro preclinical models to study the mechanism(s) of this association. Obesity increased relapse after monotherapy with vincristine (P = 0.03) in obese mice injected with syngeneic ALL cells. This occurred although the drug was dosed proportionally to body weight, equalizing blood and tissue drug levels. In coculture, 3T3-L1 adipocytes significantly impaired the antileukemia efficacy of vincristine, as well as three other chemotherapies (P < 0.05). Interestingly, this protection was independent of cell-cell contact, and it extended to human leukemia cell lines as well. Adipocytes prevented chemotherapy-induced apoptosis, and this was associated with increased expression of the two prosurvival signals Bcl-2 and Pim-2. These findings highlight the role of the adipocyte in fostering leukemia chemotherapy resistance, and may help explain the increased leukemia relapse rate in obese children and adults. Given the growing prevalence of obesity worldwide, these effects are likely to have increasing importance to cancer treatment.
Purpose The ER chaperone GRP78 translocates to the surface of tumor cells and promotes survival, metastasis, and resistance to therapy. An oncogenic function of cell surface GRP78 has been attributed to the activation of phosphoinositide 3-kinase (PI3K) pathway. We intend to use a novel anti-GRP78monoclonal antibody (MAb159) to attenuate PI3K signaling and inhibit tumor growth and metastasis. Experimental Design MAb159 was characterized biochemically. Anti-tumor activity was tested in cancer cell culture, tumor xenograft models, tumor metastasis models, and spontaneous tumor models. Cancer cells and tumor tissues were analyzed for PI3K activity. MAb159 was humanized and validated for diagnostic and therapeutic application. Results MAb159 specifically recognized surface GRP78, triggered GRP78 endocytosis, and localized to tumors but not normal organs in vivo. MAb159 inhibited tumor cell proliferation and enhanced tumor cell death both in vitro and in vivo. In MAb159 treated tumors, PI3K signaling was inhibited without compensatory MAPK pathway activation. Furthermore, MAb159 halted or reversed tumor progression in the spontaneous PTEN loss driven prostate and leukemia tumor models, and inhibited tumor growth and metastasis in xenograft models. Humanized MAb159, which retains high affinity, tumor specific localization, and the anti-tumor activity, was non-toxic in mice and had desirable pharmacokinetics. Conclusions GRP78 specific antibody MAb159 modulates PI3K pathway and inhibits tumor growth and metastasis. Humanized MAb159 will enter human trials shortly.
A drawback of extensive coxib use for antitumor purposes is the risk of life-threatening side effects that are thought to be a class effect and probably due to the resulting imbalance of eicosanoid levels. 2,5-Dimethyl-celecoxib (DMC) is a close structural analogue of the selective cyclooxygenase-2 inhibitor celecoxib that lacks cyclooxygenase-2 -inhibitory function but that nonetheless is able to potently mimic the antitumor effects of celecoxib in vitro and in vivo. To further establish the potential usefulness of DMC as an anticancer agent, we compared DMC and various coxibs and nonsteroidal anti-inflammatory drugs with regard to their ability to stimulate the endoplasmic reticulum (ER) stress response (ESR) and subsequent apoptotic cell death. We show that DMC increases intracellular free calcium levels and potently triggers the ESR in various tumor cell lines, as indicated by transient inhibition of protein synthesis, activation of ER stressassociated proteins GRP78/BiP, CHOP/GADD153, and caspase-4, and subsequent tumor cell death. Small interfering RNA -mediated knockdown of the protective chaperone GRP78 further sensitizes tumor cells to killing by DMC, whereas inhibition of caspase-4 prevents druginduced apoptosis. In comparison, celecoxib less potently replicates these effects of DMC, whereas none of the other tested coxibs (rofecoxib and valdecoxib) or traditional nonsteroidal anti-inflammatory drugs (flurbiprofen, indomethacin, and sulindac) trigger the ESR or cause apoptosis at comparable concentrations. The effects of DMC are not restricted to in vitro conditions, as this drug also generates ER stress in xenografted tumor cells in vivo, concomitant with increased apoptosis and reduced tumor growth. We propose that it might be worthwhile to further evaluate the potential of DMC as a non-coxib alternative to celecoxib for anticancer purposes.
The proteasome inhibitor bortezomib (Velcade) is known to trigger endoplasmic reticulum (ER) stress via the accumulation of obsolete and damaged proteins. The selective cyclooxygenase-2 (COX-2) inhibitor celecoxib (Celebrex) causes ER stress through a different mechanism (i.e., by causing leakage of calcium from the ER into the cytosol). Each of these two mechanisms has been implicated in the anticancer effects of the respective drug. We therefore investigated whether the combination of these two drugs would lead to further increased ER stress and would enhance their antitumor efficacy. With the use of human glioblastoma cell lines, we show that this is indeed the case. When combined, bortezomib and celecoxib triggered elevated expression of the ER stress markers GRP78/BiP and CHOP/ GADD153, caused activation of c-Jun NH 2 -terminal kinase and ER stress-associated caspase-4, and greatly increased apoptotic cell death. Small interfering RNA-mediated knockdown of the protective ER chaperone GRP78/BiP further sensitized the tumor cells to killing by the drug combination. The contribution of celecoxib was independent of the inhibition of COX-2 because a non-coxib analogue of this drug, 2,5-dimethyl-celecoxib (DMC), faithfully and more potently mimicked these combination effects in vitro and in vivo. Taken together, our results show that combining bortezomib with celecoxib or DMC very potently triggers the ER stress response and results in greatly increased glioblastoma cytotoxicity. We propose that this novel drug combination should receive further evaluation as a potentially effective anticancer therapy. [Cancer Res 2008;68(3):843-51]
Sjögren’s syndrome (SjS) is a chronic autoimmune disease characterized initially by lymphocytic infiltration and destruction of exocrine glands, followed by systemic organ damage and B-cell lymphoma. Conventional treatment is based on management of symptoms and there is a shortage of therapies that address the underlying causes of inflammation at source exocrine tissue. The aim of this study was to test a novel protein polymer-based platform consisting of diblock copolymers composed from Elastin-like Polypeptides (ELPs) fused with FKBP12, to deliver a potent immunosuppressant with dose-limiting toxicity, rapamycin (Rapa) also known as Sirolimus, and evaluate its effects on the inflamed lacrimal gland (LG) of non-obese diabetic mouse (NOD), a classic mouse model of SjS. Both soluble and diblock copolymer ELPs were fused to FKBP12 and characterized with respect to purity, hydrodynamic radii, drug entrapment and release. Both formulations showed successful association with Rapa; however, the nanoparticle formulation, FSI, released drug with nearly a 5 fold longer terminal half-life of 62.5h. The strong interaction of FSI nanoparticles with Rapa was confirmed in vivo by a shift in the monoexponential pharmacokinetic profile for free drug to a biexponential profile for the nanoparticle formulation. When acutely administered by injection into NOD mice via the tail vein, this FSI formulation significantly suppressed lymphocytic infiltration in the LG relative to the control group while reducing toxicity. There was also a significant effect on inflammatory and mammalian target of Rapamycin (mTOR) pathway genes in the LG and surprisingly, our nanoparticle formulation was significantly better at decreasing a proposed tear biomarker of SjS, cathepsin S (CATS) compared to free drug. These findings suggest that FSI is a promising tool for delivering Rapa for treatment of SjS in a murine model and may be further explored to meet the unmet medical challenge of SjS.
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