ABSTRACT
Bortezomib and the other licensed 20S proteasome inhibitors show robust activity against liquid tumors like multiple myeloma, but have disappointed against solid tumors including ovarian cancer. Consequently, interest is mounting in alternative non-peptide based drugs targeting the proteasome's 19S regulatory particle subunit, including its ubiquitin receptor RPN13. RA183 and RA375 are more potent analogs of the prototypic inhibitor of RPN13 (iRPN13) called RA190, and they show promise for the treatment of ovarian cancer. Here we demonstrate that rendering these candidate RPN13 inhibitors chiral and asymmetric through the addition of a single methyl to the core piperidone moiety increases their potency against cancer cell lines, with the S-isomer being more active than the R-isomer. The enhanced cancer cell cytotoxicities of these compounds are associated with improved binding to RPN13 in cell lysates, ATP depletion by inhibition of glycolysis and mitochondrial electron chain transport, mitochondrial depolarization and perinuclear clustering, oxidative stress and glutathione depletion, and rapid accumulation of high molecular weight polyubiquitinated proteins with a consequent unresolved ubiquitin proteasome system (UPS) stress response. Cytotoxicity was associated with an early biomarker of apoptosis, increased surface annexin V binding. As for cisplatin, BRCA2 and ATM deficiency conferred increased sensitivity to these iRPN13s. Ubiquitination plays an important role in coordinating DNA damage repair and the iRPN13s may compromise this process by depletion of monomeric ubiquitin following its sequestration in high molecular weight polyubiquitinated protein aggregates. Indeed, a synergistic cytotoxic response was evident upon treatment of several ovarian cancer cell lines with either cisplatin or doxorubicin and our new candidate iRPN13s, suggesting that such a combination approach warrants further exploration for the treatment of ovarian cancer.
Subject(s)
Antineoplastic Agents , Benzylidene Compounds , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Ovarian Neoplasms/drug therapy , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Benzylidene Compounds/chemistry , Benzylidene Compounds/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Female , Humans , Mice , Mice, Inbred C57BL , Mice, Nude , Ubiquitination/drug effectsABSTRACT
BACKGROUND: Interdisciplinary pain rehabilitation programs are an evidence-based biopsychosocial treatment approach for chronic pain. The purpose of the current study is to assess outcomes for a 10-week interdisciplinary, acceptance and commitment therapy (ACT)-based, outpatient treatment model and to evaluate the relationship between psychological process variables (ie, pain catastrophizing, pain acceptance, pain self-efficacy) and treatment outcomes. METHODS: 137 adults with chronic pain completed an interdisciplinary pain rehabilitation program. Measures of pain, pain interference, health-related quality of life, anxiety, depressed mood, insomnia, pain catastrophizing, pain acceptance, and pain self-efficacy were completed at admission and discharge. Data were also collected on demographic and clinical variables, including opioid use. RESULTS: Results indicated significant changes in all measures at program discharge compared to admission. Opioid doses were also reduced. Results of within-subjects meditational analyses indicated that pain catastrophizing accounted for a significant portion of the treatment effect for pain severity, pain interference, and depressed mood. Pain acceptance was a mediator for change in depressed mood, whereas pain self-efficacy was a mediator for pain interference outcomes. CONCLUSIONS: This study supports a 10-week, ACT-based treatment model for interdisciplinary chronic pain rehabilitation. In addition, pain catastrophizing, pain acceptance, and pain self-efficacy were each found to be mechanisms by which individuals achieve successful treatment outcomes. This research provides further support for interdisciplinary rehabilitation approaches for chronic pain.
Subject(s)
Acceptance and Commitment Therapy/methods , Chronic Pain/rehabilitation , Pain Management/methods , Adolescent , Adult , Aged , Aged, 80 and over , Catastrophization/psychology , Chronic Pain/psychology , Female , Humans , Male , Middle Aged , Retrospective Studies , Treatment Outcome , Young AdultABSTRACT
RNA tracking allows researchers to visualize RNA molecules in cells and tissues, providing important spatio-temporal information regarding RNA dynamics and function. Methods such as fluorescent in situ hybridization (FISH) and molecular beacons rely on complementary oligonucleotides to label and view endogenous transcripts. Other methods create artificial chimeric transcripts coupled with bacteriophage-derived coat proteins (e.g. MS2, λN) to tag molecules in live cells. In other approaches, endogenous RNAs are recognized by complementary RNAs complexed with noncatalytic Cas proteins. Each technique has its own set of strengths and limitations that must be considered when planning an experiment. Here, we discuss the mechanisms, advantages, and weaknesses of in situ hybridization, molecular beacons, MS2 tagging and Cas-derived systems, as well as how RNA tracking can be employed to study various aspects of molecular biology.
