Targeting Multiple End Organs in Lupus and Other Systemic Rheumatic Diseases by Inhibiting Bruton's Tyrosine Kinase.

Bruton tyrosine kinase (Btk) plays a vital role in activating and differentiating B-cells and regulating signaling in myeloid cells. Indeed, the potential use of Btk inhibitors in preventing lupus has been reported. Here, we extend these observations to 4 additional models of end-organ inflammation: (a) BWF1 lupus nephritis mice, (b) anti-GBM nephritis, (c) bleomycin-induced systemic sclerosis like skin disease, and (d) bleomycin-induced lung disease. In agreement with the previous studies, BTK inhibitor (BTKB66) treatment was effective in treating lupus nephritis in terms of reducing renal damage both functionally and histologically, accompanied by significant decrease in proteinuria. Both low-dose and high-dose BTKB66 profoundly blocked renal disease in the anti-GBM nephritis model, with efficacy that was comparable to that seen with dexamethasone. This study provides the first evidence that BTK inhibition has both therapeutic and preventative effects in bleomycin-induced SSc-like disease, in terms of reducing skin thickness, fibrosis, collagen deposition, and inflammation. Likewise, significantly lower lung inflammatory cell infiltration was observed after treatment with BTKB66. Therapeutic benefit was associated with lower numbers of macrophages, proliferating macrophages and activated T-cells in the respective injured organs. The observation that these immune cells play key roles in driving end organ inflammation in multiple systemic rheumatic diseases have broad implications for the use of BTKB66 in managing patients with systemic rheumatic diseases where multiple end organs are afflicted, including lupus and systemic sclerosis.

Retinoblastoma RB94 enhances radiation treatment of head and neck squamous cell carcinoma.

PURPOSE: To assess whether adenovirus-mediated retinoblastoma 94 (Ad-RB94) transgene expression enhances efficacy of radiation therapy (XRT) of human head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: The HNSCC cell lines (JHU006 and JHU012) were treated in vitro and in a nude mouse xenograft model with Ad-RB94, Ad-DL312 control vector, or untreated as mock control. Cell viability and tumor growth were evaluated and combined RB94/XRT antitumor activity was analyzed by measuring DNA double-strand breaks, apoptosis-associated early DNA fragmentation, and levels of RB-regulated cell cycle progression E2F1 transcription factor. RESULTS: Ad-RB94/XRT resulted in significant HNSCC cell growth inhibition compared with XRT alone or Ad-RB94 alone in vitro and caused significant tumor regression compared with XRT alone and Ad-DL312/XRT in JHU006 and with XRT alone, Ad-DL312/XRT and Ad-RB94 alone in JHU012 in vivo. Neutral comet analysis revealed that DNA damage was significantly elevated in cells treated with Ad-RB94 alone and Ad-RB94/XRT. Tumors treated with Ad-RB94 alone showed a striking increase in early apoptosis DNA fragmentation, and DNA fragmentation was further enhanced with XRT. In addition, levels of E2F1 were up-regulated by Ad-RB94/XRT combination, whereas Ad-RB94 alone did not affect E2F1 levels and XRT alone led to down-regulation of E2F1. CONCLUSIONS: A potent antitumor effect has been observed after Ad-RB94/XRT combination treatment in HNSCC xenograft tumors. Enhanced tumor regression correlated with increased apoptosis. Ad-RB94 treatment enhances the efficacy of XRT through tumor cell sensitization by arresting the cells at the radiation-sensitive G(2)-M cell cycle and via E2F1 up-regulation.

Adenovirus-mediated retinoblastoma 94 gene transfer induces human pancreatic tumor regression in a mouse xenograft model.

PURPOSE: Gene transfer of a truncated variant of the retinoblastoma (RB) gene encoding a M(r) 94000 protein that lacks the NH(2)-terminal 112 amino acid residues, termed RB94, has been shown to inhibit proliferation of several human tumor cell types. We have assessed its therapeutic effectiveness on pancreatic cancer, one of the most aggressive and therapy-resistant types of cancer. For this purpose, preclinical studies aimed to evaluate the therapeutic potential of RB94 gene transfer in pancreatic cancer were carried out. EXPERIMENTAL DESIGN: We have compared the antiproliferative effects of adenovirus-mediated gene transfer of RBwt and RB94 at the in vitro and in vivo levels in three RB-positive human pancreatic tumor cell lines: (a). NP-9; (b). NP-18; and (c). NP-31. We have also examined their effects on cell cycle and their capacity to induce apoptosis. RESULTS: In vitro results indicate that RB94 gene transfer has stronger antiproliferative effects compared with RBwt. RB94 transduction correlated with accumulation at the S-G(2) phase of the cell cycle in the three cell lines tested and induction of apoptosis in two of them. In vivo studies show significant decreases in the growth rate of tumors treated with Ad-RB94 when compared with those treated with Ad-RBwt. Moreover, terminal deoxynucleotidyl transferase-mediated nick end labeling analyses of Ad-RB94-treated tumor sections revealed that only RB94 is able to significantly induce apoptosis. CONCLUSIONS: RB94 gene expression has antiproliferative effects also in human pancreatic tumor cells, being more effective than wild-type RB in preventing tumor growth.

The R1 resistance gene cluster contains three groups of independently evolving, type I R1 homologues and shows substantial structural variation among haplotypes of Solanum demissum.

Cultivated and wild potatoes contain a major disease-resistance cluster on the short arm of chromosome V, including the R1 resistance (R) gene against potato late blight. To explore the functional and evolutionary significance of clustering in the generation of novel disease-resistance genes, we constructed three approximately 1 Mb physical maps in the R1 gene region, one for each of the three genomes (haplotypes) of allohexaploid Solanum demissum, the wild potato progenitor of the R1 locus. Totals of 691, 919 and 559 kb were sequenced for each haplotype, and three distinct resistance-gene families were identified, one homologous to the potato R1 gene and two others homologous to either the Prf or the Bs4 R-gene of tomato. The regions with R1 homologues are highly divergent among the three haplotypes, in contrast to the conserved flanking non-resistance gene regions. The R1 locus shows dramatic variation in overall length and R1 homologue number among the three haplotypes. Sequence comparisons of the R1 homologues show that they form three distinct clades in a distance tree. Frequent sequence exchanges were detected among R1 homologues within each clade, but not among those in different clades. These frequent sequence exchanges homogenized the intron sequences of homologues within each clade, but did not homogenize the coding sequences. Our results suggest that the R1 homologues represent three independent groups of fast-evolving type I resistance genes, characterized by chimeric structures resulting from frequent sequence exchanges among group members. Such genes were first identified among clustered RGC2 genes in lettuce, where they were distinguished from slow-evolving type II R-genes. Our findings at the R1 locus in S. demissum may indicate that a common or similar mechanism underlies the previously reported differentiation of type I and type II R-genes and the differentiation of type I R-genes into distinct groups, identified here.