Frontline pembrolizumab monotherapy for metastatic non-small cell lung cancer with PD-L1 expression ≥50%: real-world outcomes in a US community oncology setting.

Background: This study investigated real-world time on treatment (rwToT) and overall survival (OS) for patients with metastatic non-small cell lung cancer (mNSCLC) who initiated first-line (1L) pembrolizumab monotherapy. We also explored discontinuation reasons and subsequent treatments, stratified by number of cycles among those who completed ≥17 cycles of 1L pembrolizumab. Methods: Patients with mNSCLC without actionable genetic aberrations, Eastern Cooperative Oncology Group performance status (ECOG PS) 0-2 and unknown, and PD-L1 TPS ≥ 50% starting 1L pembrolizumab monotherapy between 24-Oct-2016 and 31-Dec-2018 within The US Oncology Network were identified retrospectively and evaluated using structured data, with a data cutoff of 30-Sep-2021. Patient characteristics and disposition were summarized using descriptive statistics. OS and rwToT were evaluated using Kaplan-Meier method for all ECOG PS and PS 0-1. A subgroup of patients who completed ≥17 cycles were evaluated using supplemental chart review data to discern reasons for discontinuation. Results: Of the 505 patients with mNSCLC with PD-L1 TPS ≥50%, 61% had ECOG PS 0-1, 23% had ECOG PS 2, and 65% had nonsquamous histology. Median rwToT and OS of pembrolizumab were 7.0 (95% CI, 6.0-8.4) months and 24.5 (95% CI, 20.1-29.3) months, respectively. In the subgroup with ECOG PS 0-1, they were 7.6 months (95% CI, 6.2-9.2) and 28.8 months (95% CI, 22.4-37.5), respectively. Of the 103 patients who completed ≥17 cycles, 57 (55.3%) patients received 17 - 34 cycles and 46 (44.7%) patients received ≥35 cycles. Approximately 7.7% of the study population received pembrolizumab beyond 35 cycles. Most common reasons for discontinuation were disease progression (38.6%) and toxicity (19.3%) among patients who received 17-34 cycles of pembrolizumab, and disease progression (13.0%) and completion of therapy (10.9%) among patients who received ≥35 cycles. Conclusion: Consistent with findings from KEYNOTE-024 and other real-world studies, this study demonstrates the long-term effectiveness of pembrolizumab monotherapy as 1L treatment for mNSCLC with PD-L1 TPS ≥50%. Among patients who completed ≥17 cycles, nearly half completed ≥35 cycles. Disease progression and toxicity were the most common reasons for discontinuation among patients who received 17-34 cycles of pembrolizumab. Reasons for discontinuation beyond 35 cycles need further exploration.

Outcomes for pembrolizumab stratified by pemetrexed maintenance post pembrolizumab-platinum-pemetrexed induction in metastatic non-small-cell lung cancer.

Aim: We assessed treatment patterns and outcomes in patients with metastatic nonsquamous non-small-cell lung cancer (mNSCLC) who initiated first-line pembrolizumab-platinum-pemetrexed (induction) in US community oncology settings. Methods: Patients initiating induction were retrospectively identified. Patients continuing pembrolizumab afterward underwent chart review. Clinical outcomes were described by maintenance pemetrexed exposure after inverse probability of treatment weighting (IPTW). Results: Median induction pembrolizumab and pemetrexed durations were 5.1 and 4.2 months. Among patients continuing pembrolizumab after induction, 64% received maintenance pemetrexed. Common discontinuation reasons for induction pemetrexed were completion of planned therapy (79%) and partial response (68%) and progressive disease (38%) and toxicity (29%) for maintenance pemetrexed. After IPTW, median overall survival and real-world progression-free survival were longer in patients continuing pembrolizumab with versus without maintenance pemetrexed (20.3 vs 12.0 months and 10.3 vs 5.8 months, respectively). Conclusion: Patient characteristics and planned treatment decisions affect maintenance pemetrexed utilization in the community oncology setting.

What is this summary about? Pembrolizumab is a drug that helps the lung cancer patient's immune system fight the cancer, even after the cancer has spread, or metastasized. After the patient gets better, the patient is treated with chemotherapy so the cancer will not come back. This is called 'maintenance treatment'. In KEYNOTE-189, a clinical trial, patients lived longer if they had pembrolizumab added to pemetrexed and platinum, which are chemotherapy drugs. If patients had maintenance treatment with pembrolizumab and pemetrexed, they also lived longer. However, do patients in community practices get those treatments? What were the results? We found that at cancer practices in the community instead of clinical trials, not all patients received pemetrexed in maintenance treatment. Many had finished their planned therapy and their tumors had shrunk. Also, some physicians chose not to give their patients pemetrexed. In addition, some women and some older and sicker patients did not get pemetrexed. Some patients had pemetrexed in maintenance but stopped because their cancer grew worse or because they had side effects. Those patients did not live as long as patients who did have maintenance pemetrexed. What do the results mean? Patients with metastatic non-small-cell lung cancer in the community practice do better on the treatments tested in clinical trials. However, certain patients do not get those treatments. The reasons need to be understood, to make sure that those patients get better treatments.

Health care services utilization in patients with ovarian cancer receiving PARP inhibitor maintenance treatment in a US community oncology setting.

OBJECTIVES: The objective of this study was to describe healthcare resource use (HCRU) in addition to treatment patterns and discontinuations, in patients with ovarian cancer (OC) initiating PARP inhibitor (PARPi) maintenance treatment in a US community oncology setting. METHODS: This was a retrospective study of patients with OC initiating PARPi monotherapy maintenance during 01/01/2017 to 06/30/2019 (followed until 12/31/2019). Patients aged ≥18 years at first diagnosis of OC with ≥2 visits within The US Oncology Network were included. Structured and chart review data as well as claims data were used to describe treatment patterns and HCRU. RESULTS: Of the 162 charts reviewed, the median age of patients was 66 years and 80% had stage III or IV disease at diagnosis. In the niraparib, rucaparib and olaparib groups, proportions of patients experiencing dose interruptions were 51%, 50%, and 28%, and discontinuations due to toxicity were 37%, 17% and 15%, respectively. Within the first 6 months, mean numbers of total claims were 43.5, 56.4, and 36.0 in the niraparib, rucaparib, and olaparib groups, and laboratory claims were 13.9, 19.4, and 15.6, respectively. Proportions of patients with hospitalizations (niraparib 40%, rucaparib 32%, olaparib 19%; p = 0.03), also differed as did emergency department visits (niraparib 37%, rucaparib 23%, olaparib 16%; p = 0.02). CONCLUSION: Despite patients initiating niraparib having higher rates of dose management events and toxicity-related discontinuations, outpatient and laboratory utilization were similar across all three PARPi. Adequate monitoring of these medications, with differing toxicities, should be emphasized to potentially decrease dose reductions and toxicities.

Temporal changes in treatment patterns by age group and functional status before and after PD-1/L1 inhibitor approvals in advanced urothelial carcinoma.

Introduction: Metastatic urothelial carcinoma (mUC) has poor prognosis. A high unmet need exists for novel treatment for those who are unfit for platinum-based chemotherapy. Methods: We aimed to describe real-world temporal changes in patient characteristics and 1L treatment selection for mUC patients in the United States following the approval of anti-PD-1/L1 treatments. This study was a retrospective, observational study using anonymized and structured oncology electronic medical record (EMR) data from IQVIA and the US Oncology Network iKnowMed (USON). Results: After approval of 1L anti-PD-1/L1 treatment for mUC, there is a marked increase in the use of 1L anti-PD-1/L1 monotherapies, accompanied by a proportional decrease in 1L platinum-based treatments and non-guideline-based therapy; particularly among the elderly (> 75 years) and those with poor ECOG performance status (ECOG PS 2+). Discussion: Anti-PD-1/L1 monotherapies fulfill the prior unmet need of frail mUC patients who are ineligible for platinum-based therapies.

Treatment patterns and outcomes for patients with newly diagnosed glioblastoma multiforme: a retrospective cohort study.

Aim: Investigate real-world outcomes and healthcare utilization of patients with glioblastoma multiforme (GBM) related to O6-methylguanine DNA methyltransferase (MGMT) promoter testing and methylation. Patients & methods: US Oncology Network data were analyzed for patients receiving first-line (1L) treatment for GBM. Results: Most patients received 1L radiation with temozolomide. Unadjusted median overall survival (OS) was higher in tested versus untested (median:18.1 vs 11.8 months) and in methylated versus unmethylated (median: 25.5 vs 12.4 months). Untested status, unmethylated MGMT and older age were associated with reduced OS and longer 1L treatment with increased OS. Similar findings were observed for progression-free survival. Utilization was similar between cohorts. Conclusion: In community oncology practices, MGMT methylation and testing were predictive of better survival in GBM.

Lay abstract We studied the characteristics and survival of patients with newly diagnosed glioblastoma multiforme (GBM) in community-based oncology practices. These patients had received temozolomide and radiotherapy with surgery, which is the standard of care for GBM. We were interested in how patient survival was related to methylation of the O⁶-methylguanine DNA methyltransferase (MGMT) promoter. The study showed that patients with methylated versus unmethylated MGMT GBM survived longer. However, patients who were tested for methylation, whether MGMT was methylated or not, also survived longer. This may be because patients who get tested also get better care in general.

Recurrence rates in patients with HER2+ breast cancer who achieved a pathological complete response after neoadjuvant pertuzumab plus trastuzumab followed by adjuvant trastuzumab: a real-world evidence study.

PURPOSE: This study assessed real-world risk of invasive disease recurrence (IDR) and associated factors in patients with human epidermal growth factor receptor-2 positive (HER2+) early breast cancer (BC) with pathological complete responses (pCR) after neoadjuvant pertuzumab plus trastuzumab (nPT) plus chemotherapy, followed by adjuvant trastuzumab (aT). METHODS: Patients with HER2+ BC with pCR after nPT from 2013 to 2015 who received aT were identified in the US Oncology Network and followed until IDR or censoring. Kaplan-Meier and Cox regression methods were used to assess invasive disease-free survival (iDFS) and correlation between iDFS and patient characteristics. RESULTS: A total of 217 pCR patients' charts were reviewed; median age was 52 years. Most had stage IIA or IIB disease (62%), Eastern Cooperative Oncology Group performance status (ECOG PS) ≤ 1 (84%), tumor size > 2 cm (75%), positive nodes (N+, 62%) and negative estrogen and progesterone receptor (ER- and PR-) expression (52%). Four-year iDFS rates were 90.0% overall (95% CI 84.6%, 93.6%), 86.2% for the N+ cohort and 96.0% for the N- cohort. Cox regression suggested that age, body mass index, ECOG PS, N+ status, stage T3 or T4, and ER+ or PR+ status were risk factors for IDR but were not statistically significant. CONCLUSIONS: Consistent with previous studies, this real-world study observed that patients with HER2+ BC showing pCR with nPT remain at risk for IDR, especially with node-positive disease at diagnosis. Alternatives to adjuvant trastuzumab alone, including combined trastuzumab and pertuzumab, should be considered to improve outcomes for initially N+ patients showing pCR with nPT.

New insights into risk factors for transplant-associated thrombotic microangiopathy in pediatric HSCT.

This study aimed to identify a risk profile for development of transplant-associated thrombotic microangiopathy (TA-TMA) in children undergoing hematopoietic stem cell transplantation (HSCT). Between 2013 and 2016, 439 children underwent 474 HSCTs at 2 supraregional United Kingdom centers. At a median of 153 days post-HSCT, TA-TMA occurred among 25 of 441 evaluable cases (5.6%) with no evidence of center variation. Sex, underlying disease, intensity of the conditioning, total body irradiation-based conditioning, the use of calcineurin inhibitors, venoocclusive disease, and viral reactivation did not influence the development of TA-TMA. Donor type: matched sibling donor/matched family donor vs matched unrelated donor vs mismatched unrelated donor/haplo-HSCT, showed a trend toward the development of TA-TMA in 1.8% vs 6.1% vs 8.3%, respectively. Presence of active comorbidity was associated with an increased risk for TA-TMA; 13% vs 3.7% in the absence of comorbidity. The risk of TA-TMA was threefold higher among patients who received >1 transplant. TA-TMA rates were significantly higher among patients with acute graft-versus-host disease (aGVHD) grades III to IV vs aGVHD grade 0 to II. On multivariate analysis, the presence of active comorbidity, >1 transplant, aGVHD grade III to IV were risk factors for TA-TMA (odds ratio [OR]: 5.1, 5.2, and 26.9; respectively), whereas the use of cyclosporine A/tacrolimus-based GVHD prophylaxis was not a risk factor for TA-TMA (OR: 0.3). Active comorbidity, subsequent transplant, and aGVHD grades III to IV were significant risk factors for TA-TMA. TA-TMA might represent a form of a vascular GVHD, and therefore, continuing control of aGVHD is important to prevent worsening of TA-TMA associated with GVHD.

Interpretable multimodal deep learning for real-time pan-tissue pan-disease pathology search on social media.

Pathologists are responsible for rapidly providing a diagnosis on critical health issues. Challenging cases benefit from additional opinions of pathologist colleagues. In addition to on-site colleagues, there is an active worldwide community of pathologists on social media for complementary opinions. Such access to pathologists worldwide has the capacity to improve diagnostic accuracy and generate broader consensus on next steps in patient care. From Twitter we curate 13,626 images from 6,351 tweets from 25 pathologists from 13 countries. We supplement the Twitter data with 113,161 images from 1,074,484 PubMed articles. We develop machine learning and deep learning models to (i) accurately identify histopathology stains, (ii) discriminate between tissues, and (iii) differentiate disease states. Area Under Receiver Operating Characteristic (AUROC) is 0.805-0.996 for these tasks. We repurpose the disease classifier to search for similar disease states given an image and clinical covariates. We report precision@k = 1 = 0.7618 ± 0.0018 (chance 0.397 ± 0.004, mean ±stdev ). The classifiers find that texture and tissue are important clinico-visual features of disease. Deep features trained only on natural images (e.g., cats and dogs) substantially improved search performance, while pathology-specific deep features and cell nuclei features further improved search to a lesser extent. We implement a social media bot (@pathobot on Twitter) to use the trained classifiers to aid pathologists in obtaining real-time feedback on challenging cases. If a social media post containing pathology text and images mentions the bot, the bot generates quantitative predictions of disease state (normal/artifact/infection/injury/nontumor, preneoplastic/benign/low-grade-malignant-potential, or malignant) and lists similar cases across social media and PubMed. Our project has become a globally distributed expert system that facilitates pathological diagnosis and brings expertise to underserved regions or hospitals with less expertise in a particular disease. This is the first pan-tissue pan-disease (i.e., from infection to malignancy) method for prediction and search on social media, and the first pathology study prospectively tested in public on social media. We will share data through http://pathobotology.org . We expect our project to cultivate a more connected world of physicians and improve patient care worldwide.

Spirometry evaluation to assess performance of a claims-based predictive model identifying patients with undiagnosed COPD.

BACKGROUND: A claims-based model to predict patients likely to have undiagnosed COPD was developed by Moretz et al in 2015. This study aims to assess the performance of the aforementioned model using prospectively collected spirometry data. METHODS: A study population aged 40-89 years enrolled in a Medicare Advantage plan with prescription drug coverage or commercial health plan and without a claim for COPD diagnosis was identified from April 1, 2012 to March 31, 2016 in the Humana claims database. This population was stratified into subjects likely or unlikely to have undiagnosed COPD using the claims-based predictive model. Subjects were randomly selected for spirometry evaluation of FEV1 and FVC. The predictive model was validated using airflow limitation ratio (FEV1/FVC <0.70). RESULTS: A total of 218 subjects classified by the predictive model as likely and 331 not likely to have undiagnosed COPD completed spirometry evaluation. Those predicted to have undiagnosed COPD had a higher mean age (70.2 vs 67.9 years, P=0.0012) and a lower mean FEV1/FVC ratio (0.724 vs 0.753, P=0.0002) compared to those predicted not to have undiagnosed COPD. Performance metrics for the predictive model were: area under the curve =0.61, sensitivity =52.5%, specificity =64.6%, positive predictive value =33.5%, and negative predictive value =80.1%. CONCLUSION: The claims-based predictive model identifies those not at risk of having COPD eight out of ten times, and those who are likely to have COPD one out of three times.

Development and validation of a predictive model to identify patients at risk of severe COPD exacerbations using administrative claims data.

Background: Patients with COPD often experience severe exacerbations involving hospitalization, which accelerate lung function decline and reduce quality of life. This study aimed to develop and validate a predictive model to identify patients at risk of developing severe COPD exacerbations using administrative claims data, to facilitate appropriate disease management programs. Methods: A predictive model was developed using a retrospective cohort of COPD patients aged 55-89 years identified between July 1, 2010 and June 30, 2013 using Humana's claims data. The baseline period was 12 months postdiagnosis, and the prediction period covered months 12-24. Patients with and without severe exacerbations in the prediction period were compared to identify characteristics associated with severe COPD exacerbations. Models were developed using stepwise logistic regression, and a final model was chosen to optimize sensitivity, specificity, positive predictive value (PPV), and negative PV (NPV). Results: Of 45,722 patients, 5,317 had severe exacerbations in the prediction period. Patients with severe exacerbations had significantly higher comorbidity burden, use of respiratory medications, and tobacco-cessation counseling compared to those without severe exacerbations in the baseline period. The predictive model included 29 variables that were significantly associated with severe exacerbations. The strongest predictors were prior severe exacerbations and higher Deyo-Charlson comorbidity score (OR 1.50 and 1.47, respectively). The best-performing predictive model had an area under the curve of 0.77. A receiver operating characteristic cutoff of 0.4 was chosen to optimize PPV, and the model had sensitivity of 17%, specificity of 98%, PPV of 48%, and NPV of 90%. Conclusion: This study found that of every two patients identified by the predictive model to be at risk of severe exacerbation, one patient may have a severe exacerbation. Once at-risk patients are identified, appropriate maintenance medication, implementation of disease-management programs, and education may prevent future exacerbations.

Association between adherence to medications for COPD and medications for other chronic conditions in COPD patients.

BACKGROUND: Patients with COPD often have multiple comorbidities requiring use of multiple medications, and adherence rates for maintenance COPD (mCOPD) medications are already known to be suboptimal. Presence of comorbidities in COPD patients, and use of medications used to treat those comorbidities (non-COPD medications), may have an adverse impact on adherence to mCOPD medications. OBJECTIVE: The objective of the study was to evaluate the association between non-adherence to mCOPD medications and non-COPD medications in COPD patients. METHODS: COPD patients were identified using a large administrative claims database. Selected patients were 40-89 years old and continuously enrolled for 12 months prior to and 24 months after the first identified COPD diagnosis (index date) during January 1, 2009 to December 31, 2010. Patients were required to have ≥1 prescription for a mCOPD medication within 365 days of the index date and ≥1 prescription for one of 12 non-COPD medication classes within ±30 days of the first COPD prescription. Adherence (proportion of days covered [PDC]) was measured during 365 days following the first COPD prescription. The association between non-adherence (PDC <0.8) to mCOPD and non-adherence to non-COPD medications was determined using logistic regression, controlling for baseline patient characteristics. RESULTS: A total of 14,117 patients, with a mean age of 69.9 years, met study criteria. Of these, 40.9% were males and 79.2% were non-adherent to mCOPD medications with a mean PDC of 0.47. Non-adherence to mCOPD medications was associated with non-adherence to 10 of 12 non-COPD medication classes (odds ratio 1.38-1.78, all P<0.01). CONCLUSION: Adherence to mCOPD medications is low. Non-adherence (or adherence) to mCOPD medications is positively related to non-adherence (or adherence) to non-COPD medications, implying that the need to take medications prescribed for comorbid conditions does not adversely impact adherence to mCOPD medications.

Characterization of Wnt/ß-catenin signaling in rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and accounts for about 5% of all malignant paediatric tumours. ß-Catenin, a multifunctional nuclear transcription factor in the canonical Wnt signaling pathway, is active in myogenesis and embryonal somite patterning. Dysregulation of Wnt signaling facilitates tumour invasion and metastasis. This study characterizes Wnt/ß-catenin signaling and functional activity in paediatric embryonal and alveolar RMS. Immunohistochemical assessment of paraffin-embedded tissues from 44 RMS showed ß-catenin expression in 26 cases with cytoplasmic/membranous expression in 9/14 cases of alveolar RMS, and 15/30 cases of embryonal RMS, whereas nuclear expression was only seen in 2 cases of embryonal RMS. The potential functional significance of ß-catenin expression was tested in four RMS cell lines, two derived from embryonal (RD and RD18) RMS and two from alveolar (Rh4 and Rh30) RMS. Western blot analysis demonstrated the expression of Wnt-associated proteins including ß-catenin, glycogen synthase kinase-3ß, disheveled, axin-1, naked, LRP-6 and cadherins in all cell lines. Cell fractionation and immunofluorescence studies of the cell lines (after stimulation by human recombinant Wnt3a) showed reduced phosphorylation of ß-catenin, stabilization of the active cytosolic form and nuclear translocation of ß-catenin. Reporter gene assay demonstrated a T-cell factor/lymphoid-enhancing factor-mediated transactivation in these cells. In response to human recombinant Wnt3a, the alveolar RMS cells showed a significant decrease in proliferation rate and induction of myogenic differentiation (myogenin, MyoD1 and myf5). These data indicate that the central regulatory components of canonical Wnt/ß-catenin signaling are expressed and that this pathway is functionally active in a significant subset of RMS tumours and might represent a novel therapeutic target.

Computational design of thermostabilizing D-amino acid substitutions.

Judicious incorporation of D-amino acids in engineered proteins confers many advantages such as preventing degradation by endogenous proteases and promoting novel structures and functions not accessible to homochiral polypeptides. Glycine to D-alanine substitutions at the carboxy termini can stabilize α-helices by reducing conformational entropy. Beyond alanine, we propose additional side chain effects on the degree of stabilization conferred by D-amino acid substitutions. A detailed, molecular understanding of backbone and side chain interactions is important for developing rational, broadly applicable strategies in using D-amino acids to increase protein thermostability. Insight from structural bioinformatics combined with computational protein design can successfully guide the selection of stabilizing D-amino acid mutations. Substituting a key glycine in the Trp-cage miniprotein with D-Gln dramatically stabilizes the fold without altering the protein backbone. Stabilities of individual substitutions can be understood in terms of the balance of intramolecular forces both at the α-helix C-terminus and throughout the protein.

Wnt/beta-catenin signaling mediates antineoplastic effects of imatinib mesylate (gleevec) in anaplastic thyroid cancer.

CONTEXT: Dysregulation of Wnt signaling is a key step in neoplastic thyrocyte proliferation. However, it is unclear whether the selective tyrosine kinase (TK) inhibitor, imatinib mesylate, is linked to the Wnt/beta-catenin cascade and is able to modulate the pathway. OBJECTIVE: Conflicting data are reported on the therapeutic effects of imatinib in anaplastic thyroid carcinomas (ATCs), but the molecular mechanism of action is unclear. Here, we further delineated the antitumor effects and the potential efficacy of imatinib in dedifferentiated thyroid carcinomas. RESULTS: Tissue microarray of histologically proven ATCs (n = 12) demonstrated that six of 12 tumors expressed at least one of the imatinib-sensitive TKs. Similarily, imatinib-sensitive TKs were detected in seven of 10 thyroid cancer cell lines derived from metastatic papillary, follicular, and ATCs. Coimmunoprecipitation in ARO cells demonstrated a direct link between c-abl and beta-catenin. Imatinib (10 microM for 48 h) drastically reduced beta-catenin expression and redistributed it from the nucleus to the cell membrane. It stabilized adherens junctions by increasing beta-catenin/E-cadherin binding and reduced the invasive potential of thyroid cancer. Furthermore, imatinib (10 microM for 48 h) attenuated T cell factor/lymphoid enhancer factor activity, reduced cyclin D1 levels and dose-dependently suppressed thyrocyte proliferation by half without affecting apoptosis. CONCLUSION: Our data provide a molecular mechanism for the antitumor activity of imatinib that may help to develop it as a therapeutic option in a subset of ATC patients.

Combination of the histone deacetylase inhibitor LBH589 and the hsp90 inhibitor 17-AAG is highly active against human CML-BC cells and AML cells with activating mutation of FLT-3.

Present studies show that LBH589, a novel cinnamic hydroxamic acid analog histone deacetylase inhibitor, induces acetylation of histone H3 and H4 and of heat shock protein 90 (hsp90), increases p21 levels, as well as induces cell-cycle G(1) phase accumulation and apoptosis of the human chronic myeloid leukemia blast crisis (CML-BC) K562 cells and acute leukemia MV4-11 cells with the activating length mutation of FLT-3. In MV4-11 cells, this was associated with marked attenuation of the protein levels of p-FLT-3, FLT-3, p-AKT, and p-ERK1/2. In K562 cells, exposure to LBH589 attenuated Bcr-Abl, p-AKT, and p-ERK1/2. Treatment with LBH589 inhibited the DNA binding activity of signal transducers and activators of transcription 5 (STAT5) in both K562 and MV4-11 cells. The hsp90 inhibitor 17-allyl-amino-demethoxy geldanamycin (17-AAG) also induced polyubiquitylation and proteasomal degradation of FLT-3 and Bcr-Abl by reducing their chaperone association with hsp90. Cotreatment with LBH589 and 17-AAG exerted synergistic apoptosis of MV4-11 and K562 cells. In the imatinib mesylate (IM)-refractory leukemia cells expressing Bcr-Abl with the T315I mutation, treatment with the combination attenuated the levels of the mutant Bcr-Abl and induced apoptosis. Finally, cotreatment with LBH589 and 17-AAG also induced more apoptosis of IM-resistant primary CML-BC and acute myeloid leukemia (AML) cells (with activating mutation of FLT-3) than treatment with either agent alone.

Mechanistic role of heat shock protein 70 in Bcr-Abl-mediated resistance to apoptosis in human acute leukemia cells.

Bcr-Abl-expressing primary or cultured leukemia cells display high levels of the antiapoptotic heat shock protein (hsp) 70 and are resistant to cytarabine (Ara-C), etoposide, or Apo-2L/TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis. Conversely, a stable expression of the cDNA of hsp70 in the reverse orientation attenuated not only hsp70 but also signal transducers and activators of transcription 5 (STAT5) and Bcl-x(L) levels. This increased apoptosis induced by cytarabine, etoposide, or Apo-2L/TRAIL. Ectopic expression of hsp70 in HL-60 cells (HL-60/hsp70) inhibited Ara-C and etoposide-induced Bax conformation change and translocation to the mitochondria; attenuated the accumulation of cytochrome c, Smac, and Omi/HtrA2 in the cytosol; and inhibited the processing and activity of caspase-9 and caspase-3. Hsp70 was bound to death receptors 4 and 5 (DR4 and DR5) and inhibited Apo-2L/TRAIL-induced assembly and activity of the death-inducing signaling complex (DISC). HL-60/hsp70 cells exhibited increased levels and DNA binding activity of STAT5, which was associated with high levels of Pim-2 and Bcl-x(L) and resistance to apoptosis. Expression of the dominant negative (DN) STAT5 resensitized HL-60/hsp70 cells to cytarabine, etoposide, and Apo-2L/TRAIL-induced apoptosis. Collectively, these findings suggest that hsp70 inhibits apoptosis upstream and downstream of the mitochondria and is a promising therapeutic target for reversing drug-resistance in chronic myeloid leukemia-blast crisis and acute myeloid leukemia cells.

Estrogenic activity of isolated compounds and essential oils of Pimpinella species from Turkey, evaluated using a recombinant yeast screen.

Several plants and plant-derived pure compounds, designated as phytoestrogens, have been reported to cause estrogenic effects. They have been used for alleviation of menopausal symptoms, prevention of osteoporosis, heart disease and cancer. There is an increased interest in studying phytoestrogens such as isoflavones and lignans for their use as replacements for synthetic estrogens. In this study, the estrogenic activity of essential oils of eleven Pimpinella species and the compounds isolated from these species were evaluated using the yeast estrogen screen (YES) assay. The essential oils containing (E)-anethole as major compound showed estrogenic activity in the YES assay, except for the aerial parts without fruits of P. anisetum and P. flabellifolia. The percent maximal response produced by most anethole-containing oils was 30-50%. Fruits of P. isaurica and P. peucedanifolia were estrogenic in spite of the absence or trace amount of anethole, respectively. This study indicates that the estrogenic activity of Pimpinella oils is not solely due to the presence of anethole. Components other than anethole may be responsible for contributing towards the estrogenic activity. The essential oils from different species varied in their estrogenic potencies (relative potency from 8.3 x 10(-8) to 1.2 x 10(-6) compared to 17 beta-estradiol) and among the different plant parts, the fruit oils of most species were estrogenic followed by the aerial parts without fruits and the root oils and their EC50 values varied from 45 micrograms/mL to 650 micrograms/mL.

Superior activity of the combination of histone deacetylase inhibitor LAQ824 and the FLT-3 kinase inhibitor PKC412 against human acute myelogenous leukemia cells with mutant FLT-3.

PURPOSE: Mutant FLT-3 receptor tyrosine kinase is a client protein of the molecular chaperone heat shock protein 90 and is commonly present and contributes to the leukemia phenotype in acute myelogenous leukemia (AML). LAQ824, a cinnamyl hydroxamate histone deacetylase inhibitor, is known to induce acetylation and inhibition of heat shock protein 90. Here, we determined the effects of LAQ824 and/or PKC412 (a FLT-3 kinase inhibitor) on the levels of mutant FLT-3 and its downstream signaling, as well as growth arrest and cell-death of cultured and primary human AML cells. EXPERIMENTAL DESIGN: The effect of LAQ824 and/or PKC412 treatment was determined on the levels of FLT-3 and phosphorylated (p)-FLT-3, on downstream pro-growth and pro-survival effectors, e.g., p-STAT5, p-AKT, and p-extracellular signal-regulated kinase (ERK) 1/2, and on the cell cycle status and apoptosis in the cultured MV4-11 and primary AML cells with mutant FLT-3. RESULTS: Treatment with LAQ824 promoted proteasomal degradation and attenuation of the levels of FLT-3 and p-FLT-3, associated with cell cycle G(1)-phase accumulation and apoptosis of MV4-11 cells. This was accompanied by attenuation of p-STAT5, p-AKT, and p-ERK1/2 levels. STAT-5 DNA-binding activity and the levels of c-Myc and oncostatin M were also down-regulated. Cotreatment with LAQ824 and PKC412 synergistically induced apoptosis of MV4-11 cells and induced more apoptosis of the primary AML cells expressing mutant FLT-3. This was also associated with more attenuation of p-FLT-3, p-AKT, p-ERK1/2, and p-STAT5. CONCLUSIONS: The combination of LAQ824 and PKC412 is highly active against human AML cells with mutant FLT-3, which merits in vivo studies of the combination against human AML.