Involvement of p38-betaTrCP-Tristetraprolin-TNFalpha axis in radiation pneumonitis

Early release of tumor necrosis factor-alpha (TNF-alpha) during radiotherapy of thoracic cancers plays an important role in radiation pneumonitis, whose inhibition may provide lung radioprotection. We previously reported radiation inactivates Tristetraprolin (TTP), a negative regulator of TNF-alpha synthesis, which correlated with increased TNF-alpha release. However, the molecular events involved in radiation-induced TTP inactivation remain unclear. To determine if eliminating Ttp in mice resulted in a phenotypic response to radiation, Ttp-null mice lungs were exposed to a single dose of 15 Gy, and TNF-alpha release and lung inflammation were analyzed at different time points post-irradiation. Ttp-/- mice with elevated (9.5+/-0.6 fold) basal TNF-alpha showed further increase (12.2+/-0.9 fold, p \u3c 0.02) in TNF-alpha release and acute lung inflammation within a week post-irradiation. Further studies using mouse lung macrophage (MH-S), human lung fibroblast (MRC-5), and exogenous human TTP overexpressing U2OS and HEK293 cells upon irradiation (a single dose of 4 Gy) promoted p38-mediated TTP phosphorylation at the serine 186 position, which primed it to be recognized by an ubiquitin ligase (E3), beta transducing repeat containing protein (beta-TrCP), to promote polyubiquitination-mediated proteasomal degradation. Consequently, a serine 186 to alanine (SA) mutant of TTP was resistant to radiation-induced degradation. Similarly, either a p38 kinase inhibitor (SB203580), or siRNA-mediated beta-TrCP knockdown, or overexpression of dominant negative Cullin1 mutants protected TTP from radiation-induced degradation. Consequently, SB203580 pretreatment blocked radiation-induced TNF-alpha release and radioprotected macrophages. Together, these data establish the involvement of the p38-betaTrCP-TTP-TNFalpha signaling axis in radiation-induced lung inflammation and identified p38 inhibition as a possible lung radioprotection strategy

Recent Advances in Combined Modality Therapy

This review highlights the recent clinical data in support of newer generation cytotoxic chemotherapies and systemic targeted agents in combination with radiation therapy

Paired phase II trials evaluating cetuximab and radiotherapy for low risk HPV associated oropharyngeal cancer and locoregionally advanced squamous cell carcinoma of the head and neck in patients not eligible for cisplatin

BackgroundAlternative therapeutic strategies are needed for localized oropharyngeal carcinoma. Cetuximab represents a potential option for those ineligible for cisplatin or, until recently, an agent for de‐escalation in low risk HPV+ oropharyngeal carcinoma (OPSCC). Our objective was to define the toxicity and efficacy of cetuximab‐radiotherapy.MethodsWe conducted paired phase II trials evaluating cetuximab‐radiotherapy in two cohorts (a) low risk HPV+ OPSCC and (b) cisplatin ineligible. The mean follow‐up was 48 months.ResultsForty‐two patients were enrolled in cohort A with a 2‐year disease free survival (DFS) of 81%. Twenty‐one patients were enrolled in cohort B prior to closure due to adverse outcomes with a 2‐year DFS of 37%. Severe toxicities were seen in 60% of patients, 30% required enteral nutrition.ConclusionAmong cisplatin ineligible patients, cetuximab treatment engendered poor outcomes. Rates of severe toxicities were on par with platinum‐based regimens suggesting that cetuximab is not a benign treatment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156234/2/hed26085.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156234/1/hed26085_am.pd

Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression

Multiple, complex molecular events characterize cancer development and progression(1,2). Deciphering the molecular networks that distinguish organ- confined disease from metastatic disease may lead to the identification of critical biomarkers for cancer invasion and disease aggressiveness. Although gene and protein expression have been extensively profiled in human tumours, little is known about the global metabolomic alterations that characterize neoplastic progression. Using a combination of high- throughput liquid- and- gas- chromatography- based mass spectrometry, we profiled more than 1,126 metabolites across 262 clinical samples related to prostate cancer ( 42 tissues and 110 each of urine and plasma). These unbiased metabolomic profiles were able to distinguish benign prostate, clinically localized prostate cancer and metastatic disease. Sarcosine, an N- methyl derivative of the amino acid glycine, was identified as a differential metabolite that was highly increased during prostate cancer progression to metastasis and can be detected non- invasively in urine. Sarcosine levels were also increased in invasive prostate cancer cell lines relative to benign prostate epithelial cells. Knockdown of glycine- N- methyl transferase, the enzyme that generates sarcosine from glycine, attenuated prostate cancer invasion. Addition of exogenous sarcosine or knockdown of the enzyme that leads to sarcosine degradation, sarcosine dehydrogenase, induced an invasive phenotype in benign prostate epithelial cells. Androgen receptor and the ERG gene fusion product coordinately regulate components of the sarcosine pathway. Here, by profiling the metabolomic alterations of prostate cancer progression, we reveal sarcosine as a potentially important metabolic intermediary of cancer cell invasion and aggressivity.Early Detection Research Network ; National Institutes of Health ; MTTC ; Clinical Translational Science Award ; Fund for Discovery of the University of Michigan Comprehensive Cancer Center ; University of Michigan Cancer Biostatistics Training Grant ; Doris Duke Charitable FoundationWe thank J. Granger for help in manuscript preparation, J. Siddiqui and R. Varambally for help with the clinical database, and A. Vellaichamy and S. Pullela for technical assistance. We thank K. Pienta for access to metastatic prostate cancer samples from the University of Michigan Prostate SPORE rapid autopsy programme. This work is supported in part by the Early Detection Research Network (A.M.C., J.T.W.), National Institutes of Health (A.S., S.P., J.B., T.M.R., D.G., G.S.O. and A.M.C.) and an MTTC grant (G.S.O. and A.S.). A.M.C. is supported by a Clinical Translational Science Award from the Burroughs Welcome Foundation. A. S. is supported by a grant from the Fund for Discovery of the University of Michigan Comprehensive Cancer Center. L. M. P. is supported by the University of Michigan Cancer Biostatistics Training Grant. A. M. C and S. P. are supported by the Doris Duke Charitable Foundation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62661/1/nature07762.pd

Chloroquine Treatment Increases Detection of 5-Fluorouracil-Induced Apoptosis In Vivo

Although apoptosis can be readily assessed in vitro with a variety of techniques, the detection of apoptosis in the in vivo setting poses a much more difficult proposition. Apoptosis in an organism is followed almost inevitably by rapid clearance of dying cells via phagocytosis, thus limiting the ability to analyze apoptosis in vivo using classical techniques. To address this issue, we developed a method to enhance in vivo apoptosis detection using pretreatment with chloroquine, an inhibitor of macrophage activity, in Swiss albino mice. This technique resulted in a significant increase in the accumulation of apoptotic cells induced by 5-fluorouracil, as detected by propidium iodide staining in solid and ascitic forms of Ehrlich ascitic tumors and in bone marrow cells. We further validated our technique using DNA fragmentation and endonuclease assays. Our results demonstrated that chloroquine pretreatment can significantly enhance accumulation of apoptotic cells in organisms, and we envision combining this method with modern imaging techniques to optimize in vivo detection of apoptosis

Chloroquine Treatment Increases Detection of 5-Fluorouracil-Induced Apoptosis In Vivo

Although apoptosis can be readily assessed in vitro with a variety of techniques, the detection of apoptosis in the in vivo setting poses a much more difficult proposition. Apoptosis in an organism is followed almost inevitably by rapid clearance of dying cells via phagocytosis, thus limiting the ability to analyze apoptosis in vivo using classical techniques. To address this issue, we developed a method to enhance in vivo apoptosis detection using pretreatment with chloroquine, an inhibitor of macrophage activity, in Swiss albino mice. This technique resulted in a significant increase in the accumulation of apoptotic cells induced by 5-fluorouracil, as detected by propidium iodide staining in solid and ascitic forms of Ehrlich ascitic tumors and in bone marrow cells. We further validated our technique using DNA fragmentation and endonuclease assays. Our results demonstrated that chloroquine pretreatment can significantly enhance accumulation of apoptotic cells in organisms, and we envision combining this method with modern imaging techniques to optimize in vivo detection of apoptosis

Inducing Oncoprotein Degradation to Improve Targeted Cancer Therapy

Over the past decade, inhibition of the kinase activities of oncogenic proteins using small molecules and antibodies has been a mainstay of our anticancer drug development effort, resulting in several Food and Drug Administration–approved cancer therapies. The clinical effectiveness of kinase-targeted agents has been inconsistent, mostly because of the development of resistance. The expression and function of oncoproteins and tumor suppressors are regulated by numerous posttranslational protein modifications including phosphorylation, ubiquitination, and acetylation; hence, targeting specific posttranslational protein modifications provides for an attractive strategy for anticancer drug development. The present review discusses the hypothesis that targeted degradation of an oncoprotein may overcome many of the shortcomings seen with kinase inhibitors and that the approach would enable targeted inhibition of oncogenic proteins previously thought to be undruggable