Actionable Genetic Screens Unveil Targeting of AURKA, MEK, and Fatty Acid Metabolism as an Alternative Therapeutic Approach for Advanced Melanoma

Despite the remarkable improvements achieved in the management of metastatic melanoma, there are still unmet clinical needs. A considerable fraction of patients does not respond to immune and/or targeted therapies owing to primary and acquired resistance, high-grade immune-related adverse events, and a lack of alternative treatment options. To design effective combination therapies, we set up a functional ex vivo preclinical assay on the basis of a drop-out genetic screen in metastatic melanoma patient-derived xenografts. We showed that this approach can be used to isolate actionable vulnerabilities predictive of drug efficacy. In particular, we highlighted that the dual targeting of AURKA and MAPK/extracellular signal-regulated kinase kinase employing the combination of alisertib and trametinib is highly effective in a cohort of metastatic melanoma patient-derived xenografts, both ex vivo and in vivo. Alisertib and trametinib combination therapy outperforms standard-of-care therapy in both BRAF-mutant patient-derived xenografts and targeted therapy-resistant models. Furthermore, alisertib and trametinib treatment modulates several critical cancer pathways, including an early metabolic reprogramming that leads to the transcriptional upregulation of the fatty acid oxidation pathway. This acquired trait unveiled an additional point of intervention for pharmacological targeting, and indeed, the triple combination of alisertib and trametinib with the fatty acid oxidation inhibitor etomoxir proved to be further beneficial, inducing tumor regression and remarkably prolonging the overall survival of the mice.

Low neutrophil-to-lymphocyte ratio and pan-immune-inflammation-value predict nodal pathologic complete response in 1274 breast cancer patients treated with neoadjuvant chemotherapy: a multicenter analysis

Background

Systemic inflammatory markers draw great interest as potential blood-based prognostic factors in several oncological settings.

Objectives

The aim of this study is to evaluate whether neutrophil-to-lymphocyte ratio (NLR) and pan-immune-inflammation value (PIV) predict nodal pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in node-positive (cN+) breast cancer (BC) patients.

Design

Clinically, cN+ BC patients undergoing NAC followed by breast and axillary surgery were enrolled in a multicentric study from 11 Breast Units.

Methods

Pretreatment blood counts were collected for the analysis and used to calculate NLR and PIV. Logistic regression analyses were performed to evaluate independent predictors of nodal pCR.

Results

A total of 1274 cN+ BC patients were included. Nodal pCR was achieved in 586 (46%) patients. At multivariate analysis, low NLR [odds ratio (OR) = 0.71; 95% CI, 0.51-0.98; p = 0.04] and low PIV (OR = 0.63; 95% CI, 0.44-0.90; p = 0.01) were independently predictive of increased likelihood of nodal pCR. A sub-analysis on cN1 patients (n = 1075) confirmed the statistical significance of these variables. PIV was significantly associated with axillary pCR in estrogen receptor (ER)-/human epidermal growth factor receptor 2 (HER2)+ (OR = 0.31; 95% CI, 0.12-0.83; p = 0.02) and ER-/HER2- (OR = 0.41; 95% CI, 0.17-0.97; p = 0.04) BC patients.

Conclusion

This study found that low NLR and PIV levels predict axillary pCR in patients with BC undergoing NAC.

Registration

Eudract number NCT05798806.

Quantification and prospective evaluation of serum NfL and GFAP as blood-derived biomarkers of outcome in acute ischemic stroke patients

Identification of reliable and accessible biomarkers to characterize ischemic stroke patients' prognosis remains a clinical challenge. Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) are markers of brain injury, detectable in blood by high-sensitive technologies. Our aim was to measure serum NfL and GFAP after stroke, and to evaluate their correlation with functional outcome and the scores in rehabilitation scales at 3-month follow-up. Stroke patients were prospectively enrolled in a longitudinal observational study within 24 hours from symptom onset (D1) and monitored after 7 (D7), 30 ± 3 (M1) and 90 ± 5 (M3) days. At each time-point serum NfL and GFAP levels were measured by Single Molecule Array and correlated with National Institute of Health Stroke Scale (NIHSS), modified Rankin scale (mRS), Trunk Control Test (TCT), Functional Ambulation Classification (FAC) and Functional Independence Measure (FIM) scores. Serum NfL and GFAP showed different temporal profiles: NfL increased after stroke with a peak value at D7; GFAP showed an earlier peak at D1. NfL and GFAP concentrations correlated with clinical/rehabilitation outcomes both longitudinally and prospectively. Multivariate analysis revealed that NfL-D7 and GFAP-D1 were independent predictors of 3-month NIHSS, TCT, FAC and FIM scores, with NfL being the biomarker with the best predictive performance.

Dynamic prostate cancer transcriptome analysis delineates the trajectory to disease progression

Comprehensive genomic studies have delineated key driver mutations linked to disease progression for most cancers. However, corresponding transcriptional changes remain largely elusive because of the bias associated with cross-study analysis. Here, we overcome these hurdles and generate a comprehensive prostate cancer transcriptome atlas that describes the roadmap to tumor progression in a qualitative and quantitative manner. Most cancers follow a uniform trajectory characterized by upregulation of polycomb-repressive-complex-2, G2-M checkpoints, and M2 macrophage polarization. Using patient-derived xenograft models, we functionally validate our observations and add single-cell resolution. Thereby, we show that tumor progression occurs through transcriptional adaption rather than a selection of pre-existing cancer cell clusters. Moreover, we determine at the single-cell level how inhibition of EZH2 - the top upregulated gene along the trajectory - reverts tumor progression and macrophage polarization. Finally, a user-friendly web-resource is provided enabling the investigation of dynamic transcriptional perturbations linked to disease progression.

Commensal bacteria promote endocrine resistance in prostate cancer through androgen biosynthesis

[Figure: see text].

Long non-coding RNA TINCR suppresses metastatic melanoma dissemination by preventing ATF4 translation

Transition from proliferative‐to‐invasive phenotypes promotes metastasis and therapy resistance in melanoma. Reversion of the invasive phenotype, however, is challenged by the poor understanding of mechanisms underlying its maintenance. Here, we report that the lncRNA TINCR is down‐regulated in metastatic melanoma and its silencing increases the expression levels of invasive markers, in vitro migration, in vivo tumor growth, and resistance to BRAF and MEK inhibitors. The critical mediator is ATF4, a central player of the integrated stress response (ISR), which is activated in TINCR‐depleted cells in the absence of starvation and eIF2α phosphorylation. TINCR depletion increases global protein synthesis and induces translational reprogramming, leading to increased translation of mRNAs encoding ATF4 and other ISR proteins. Strikingly, re‐expression of TINCR in metastatic melanoma suppresses the invasive phenotype, reduces numbers of tumor‐initiating cells and metastasis formation, and increases drug sensitivity. Mechanistically, TINCR interacts with mRNAs associated with the invasive phenotype, including ATF4, preventing their binding to ribosomes. Thus, TINCR is a suppressor of the melanoma invasive phenotype, which functions in nutrient‐rich conditions by repressing translation of selected ISR RNAs.

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

BACKGROUND

80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality.

METHODS

This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494.

FINDINGS

Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70-8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39-8·80) and upper-middle-income countries (2·06, 1·11-3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26-11·59) and upper-middle-income countries (3·89, 2·08-7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications.

INTERPRETATION

Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications.

FUNDING

National Institute for Health Research Global Health Research Unit.

Abstract A15: New treatment opportunities by in vivo and in vitro screening approaches in melanoma

Treatment of metastatic melanoma has been recently revolutionized by the use of targeted and immune inhibitors, though efficiently working only in a fraction of patients. Adverse effects still represent major challenges, as well as the rapid development of drug resistance upon treatment, thus suggesting that it is of utmost importance to elucidate additional molecular pathways and targets to better understand the biology of this tumor. In vivo RNAi screens done in patient-derived xenografts (PDXs) that fully phenocopy the original tumor of the patient represent a powerful tool to identify new putative essential and druggable candidates, and to repurpose drugs already approved for other indications. To this end we have recently generated a platform of melanoma PDXs with which we can recapitulate both melanoma growth and metastasization. We have performed in vivo shRNA screens, where we have found numerous and patient-specific epigenetic genes essential for tumor growth in vivo. With this platform, we have isolated novel frailties whose depletion favors cell senescence. Preliminary data using shRNA libraries of actionable genes for which drugs are already available suggest that specific drugs can be repurposed for melanoma treatment. We have proved that this approach can work in vivo, and we propose to convert it in an in vitro assay to rapidly translate new discoveries to the patient.

Note: This abstract was not presented at the conference.

Citation Format: Federica Marocchi, Letizia Granieri, Fiorenza Lotti, Fernando Palluzzi, Jole Costanza, Laura Riva, Daniela Bossi, Luisa Lanfrancone. New treatment opportunities by in vivo and in vitro screening approaches in melanoma [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr A15.

Prediction of nodal staging in breast cancer patients with 1-2 sentinel nodes in the Z0011 era

The aim of this study was to provide an innovative nomogram to predict the risk of >2 positive nodes in patients fulfilling the Z0011 criteria with 1-2 sentinel lymph nodes (SLNs) only retrieved.From 2007 to 2017, at the Breast Unit of ICS Maugeri Hospital 271 patients with 1-2 macrometastatic SLNs, fulfilling the Z0011 criteria, underwent axillary dissection and were retrospectively reviewed.A mean of 1.5 SLNs per patient were identified and retrieved. One hundred eighty-seven (69.0%) had 1-2 positive nodes, and 84 (31.0%) had >2 metastatic nodes. Independent predictors of axillary status were: positive SLNs/retrieved SLNs ratio (odds ratio [OR] 10.95, P = .001), extranodal extension (OR 5.51, P = .0002), and multifocal disease (OR 2.9, P = .003). A nomogram based on these variables was constructed (area under curve after bootstrap = 0.74).The proposed nomogram might select those patients fulfilling the Z0011 criteria, with 1-2 SLNs harvested, in whom a high axillary tumor burden is expected, aiding to guide adjuvant treatments.

Modeling cell proliferation in human acute myeloid leukemia xenografts

Motivation

Acute myeloid leukemia (AML) is one of the most common hematological malignancies, characterized by high relapse and mortality rates. The inherent intra-tumor heterogeneity in AML is thought to play an important role in disease recurrence and resistance to chemotherapy. Although experimental protocols for cell proliferation studies are well established and widespread, they are not easily applicable to in vivo contexts, and the analysis of related time-series data is often complex to achieve. To overcome these limitations, model-driven approaches can be exploited to investigate different aspects of cell population dynamics.

Results

In this work, we present ProCell, a novel modeling and simulation framework to investigate cell proliferation dynamics that, differently from other approaches, takes into account the inherent stochasticity of cell division events. We apply ProCell to compare different models of cell proliferation in AML, notably leveraging experimental data derived from human xenografts in mice. ProCell is coupled with Fuzzy Self-Tuning Particle Swarm Optimization, a swarm-intelligence settings-free algorithm used to automatically infer the models parameterizations. Our results provide new insights on the intricate organization of AML cells with highly heterogeneous proliferative potential, highlighting the important role played by quiescent cells and proliferating cells characterized by different rates of division in the progression and evolution of the disease, thus hinting at the necessity to further characterize tumor cell subpopulations.

Availability and implementation

The source code of ProCell and the experimental data used in this work are available under the GPL 2.0 license on GITHUB at the following URL: https://github.com/aresio/ProCell.

Supplementary information

Supplementary data are available at Bioinformatics online.

Abstract P3-07-04: A dedicated nomogram to predict nodal pathological complete response in node-positive breast cancer patients undergoing neoadjuvant chemotherapy

Background and rationale In breast cancer patients with nodal metastases at presentation, neoadjuvant chemotherapy (NAC) may downstage axillary disease. Until a few years ago, axillary lymph node dissection (ALND) has been the standard of care for node positive disease, irrespective of nodal status after completion of NAC. However, nodal pathologic complete response (pCR) is well documented in about 40-70% of women presenting with cN+ status at baseline. In this subset of patiens, ALND is therefore unnecessary. Sentinel lymph node (SLN) biopsy is accepted as a staging procedure for clinically node negative patients at baseline. Recent trials have assessed the feasibility of SLN biopsy also for patients who had clinical conversion of nodal status from cN+ to ycN0, if at least three SLNs are retrieved. However, a higher false-negative rate is the major point of controversy about adoption of SLN biopsy in these patients. A preoperative predictive model, able to assess the likelihood of axillary pCR after NAC, could help to select those patients who might be suitable candidates for SLN surgery. This approach could provide reliable nodal staging information, avoiding unjustified ALNDs and associated morbidities. Methods A retrospective review of all node-positive breast cancer patients treated by NAC between November 2000 and April 2019 at the Breast Unit of IRCCS Maugeri Hospital was performed. Patients were considered as cN+ in case of palpable axillary lymph nodes and/or suspicious lymphadenopathy on ultrasound and/or biopsy-proven nodal metastasis. After NAC completion, all patients have been treated by ALND. Baseline pre-NAC and post-NAC variables were collected and analyzed in a multivariate analysis to find predictors of axillary pCR. Identified predictors were included to develop a dedicated nomogram. Results A total of 371 clinically node-positive patients were identified. Axillary pCR (ypN0 status) was achieved in 142 patients (38%). In multivariate analysis, post-NAC clinical N stage (ycN0 vs ycN+, OR 4.61, 95%CI 2.73-7.78, p<0.0001), biomolecular subtype (for triple-negative breast cancer: OR 4.36, 95%CI 1.45-13.15, p=0.009; for ER+/HER2+: OR 3.68, 95%CI 1.86-7.3, p=0.0002; for ER-/HER2+: OR 3.03, 95%CI 1.06-8.62, p=0.038)-) and clinical complete response on the breast assessed on ultrasound (OR 2.26, 95%CI 1.11-4.59, p=0.024) resulted to be the strongest indipendent predictors of axillary pCR. Based on statistical findings and clinically relevant factors, a nomogram for prediction of pCR after NAC was developed and included the above-mentioned variables and Ki67, grading and pre-NAC clinical T stage. The developed model demonstrated a good discrimination capacity (AUC: 0.77). Conclusions The developed nomogram could help to identify, among patiens cN+ at time of diagnosis, those more likely to achieve nodal pCR after completing NAC. In clinical practice, this tool could contribute to select suitable cadidates for SLN biopsy, preventing them from unnecessary ALND.

Citation Format: Fabio Corsi, Valentina Forlini, Daniela Bossi, Sara Albasini, Marta Truffi, Luca Sorrentino. A dedicated nomogram to predict nodal pathological complete response in node-positive breast cancer patients undergoing neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-07-04.

WDR5 inhibition halts metastasis dissemination by repressing the mesenchymal phenotype of breast cancer cells

Background

Development of metastases and drug resistance are still a challenge for a successful systemic treatment in breast cancer (BC) patients. One of the mechanisms that confer metastatic properties to the cell relies in the epithelial-to-mesenchymal transition (EMT). Moreover, both EMT and metastasis are partly modulated through epigenetic mechanisms, by repression or induction of specific related genes.

Methods

We applied shRNAs and drug targeting approaches in BC cell lines and metastatic patient-derived xenograft (PDX) models to inhibit WDR5, the core subunit of histone H3 K4 methyltransferase complexes, and evaluate its role in metastasis regulation.

Result

We report that WDR5 is crucial in regulating tumorigenesis and metastasis spreading during BC progression. In particular, WDR5 loss reduces the metastatic properties of the cells by reverting the mesenchymal phenotype of triple negative- and luminal B-derived cells, thus inducing an epithelial trait. We also suggest that this regulation is mediated by TGFβ1, implying a prominent role of WDR5 in driving EMT through TGFβ1 activation. Moreover, such EMT reversion can be induced by drug targeting of WDR5 as well, leading to BC cell sensitization to chemotherapy and enhancement of paclitaxel-dependent effects.

Conclusions

We suggest that WDR5 inhibition could be a promising pharmacologic approach to reduce cell migration, revert EMT, and block metastasis formation in BC, thus overcoming resistance to standard treatments.

Autologous fat transfer after breast cancer surgery: An exact-matching study on the long-term oncological safety

INTRODUCTION

Autologous fat transfer (AFT) is widely adopted for breast reconstruction, but its long-term oncologic safety is still not clearly established. The aim of the present study was to compare the 10-year loco-regional recurrence (LRR)-free and distant metastases (DM)-free survival probabilities in AFT vs. control patients, also evaluating the impact of AFT in different intrinsic molecular subtypes of breast cancer.

MATERIALS AND METHODS

464 AFT patients were exactly matched with a cohort of 3100 control patients treated between 2007 and 2017. A multivariate survival analysis was performed accounting for all variables related to LRR and DM, including adjuvant/neoadjuvant treatments. End-points were analyzed both overall and in each molecular subtype.

RESULTS

LRR occurred in 6.4% of AFT and in 5.0% of control patients (p = 0.42), while DM were observed respectively in 7.7% and 5.4% of cases (p = 0.20). AFT showed no effect on the 10-year LRR-free survival probability (adjusted HR 0.87, 95%CI 0.43-1.76, p = 0.69) or the 10-year DM-free survival probability (adjusted HR 0.82, 95%CI 0.43-1.57, p = 0.55). Luminal A patients treated by AFT showed a decreased LRR-free survival probability (HR 2.38, 95%CI 0.91-6.17, Log-Rank p = 0.07), which was significantly lower than controls after 80 months (Log-Rank p = 0.02). No differences in the 10-year event-free survival probability were found in Luminal B, HER2-positive or triple-negative patients.

CONCLUSION

AFT does not increase breast cancer recurrence, with the possible exception of late LRRs for Luminal A patients, but further clinical and preclinical data are required to better clarify this data. The use of AFT should not be discouraged.

Involved margins after lumpectomy for breast cancer: Always to be re-excised?

BACKGROUND

The oncologic benefit of upfront re-excision of involved margins after breast-conserving surgery in the context of current multimodal clinical management of breast cancer is unclear. The aim of the present study was to assess the 5-years locoregional recurrence (LRR)-free and distant metastases (DM)-free survival probabilities in patients not undergoing re-excision of positive margins after lumpectomy for breast cancer.

METHODS

A cohort of 104 patients with positive margins not undergoing re-excision was matched by propensity score with a cohort of 2006 control patients with clear margins after breast-conserving surgery, treated between 2008 and 2018. A multivariate survival analysis was performed accounting for all variables related to LRR and DM, including adjuvant treatments.

RESULTS

After adjusting for potential confounders, avoiding to re-excise a positive margin after lumpectomy had no effect on 5-years LRR-free survival probability (HR 0.98, 95%CI 0.36-2.67, p = 0.96) or 5-years DM-free survival probability (HR 0.37, 95%CI 0.08-1.61, p = 0.18). No correlation was found between occurrence of LRR and number of involved margins (HR 1.28, 95%CI 0.10-12.4, Log-rank p = 0.83), or extension of infiltrating disease (HR 1.21, 95%CI 0.20-7.40, Log-rank p = 0.83), but a trend toward higher LRR probability was found for invasive ductal (HR 6.92, 95%CI 0.7-68.8, Log-rank p = 0.10) and invasive lobular cancer (HR 12.95, 95%CI 0.79-213.6, Log-rank p = 0.07) on positive margins.

CONCLUSIONS

In the era of multimodal treatment of breast cancer and accurate strategies to reduce the probability of residual disease in the post-lumpectomy cavity, re-excision of positive margins might be omitted in selected patients with low-risk breast cancers.

Radio-guided and clip-guided preoperative localization for malignant microcalcifications offer similar performances in breast-conserving surgery

Obtaining a tailored breast resection is challenging in microcalcifications detected on screening mammography, and an accurate localization is required. The aim of this study was to compare the efficacy of radio-guided localization (ROLL) versus ultrasound localization of a titanium clip with collagen (TCC) in terms of clear margins, re-intervention rates, excess of resected breast tissue, and operative times in pure malignant microcalcifications detected on screening mammography. Two hundred and twenty-one consecutive patients with malignant microcalcifications detected on screening mammography from a tertiary breast unit were reviewed: 177 patients were localized by TCC and 44 patients by stereotactic ROLL. A propensity score-matched analysis was performed, followed by a logistic regression model, to avoid selection bias. Adequacy of resection was expressed as the calculated resection ratio considering lesion size. No differences were found in clear margins with ROLL versus TCC (77.3% vs 81.8%, adjusted OR 2, P = 0.27). Re-operation rates were similar, being 11.3% with ROLL and 7.4% with TCC (P = 0.627). Mean resection volume was 46.2 cm³ with ROLL versus 54.2 cm³ with TCC (P = 0.222). Adjusted mean calculated resection ratio was 1.8 with ROLL and 2.1 with TCC (P = 0.38). Surgery time was longer with TCC compared to ROLL (69.6 vs 52.7 minutes, P < 0.0001). ROLL and TCC are equally effective to excise malignant microcalcifications with clear margins, providing similar re-intervention rates and resection volumes.

One-step intraoperative radiotherapy optimizes conservative treatment of breast cancer with advantages in quality of life and work resumption

BACKGROUND

Intraoperative radiotherapy (IORT) could be not-inferior to external beam radiotherapy (EBRT) in selected patients, but toxicities, self-perception of body image, quality of life, and resumption of work or daily activities have been poorly explored. The aim of the present study was to compare these outcomes between EBRT, IORT full-dose (IORT-f) and IORT boost (IORT-b).

METHODS

443 consecutive patients, candidates for breast-conserving surgery, were included: EBRT was performed in 220 patients (49.7%), IORT-f in 140 patients (31.6%), and IORT-b in 83 patients (18.7%). Radiotherapy-related toxicities were registered. Patients were evaluated at 6 months for Body Image after Breast Cancer Questionnaire (BIBCQ) to assess possible changes in self-perception of body image and limitations. A second questionnaire explored the impact of EBRT, IORT-f and IORT-b on resumption of work and normal daily activities.

RESULTS

EBRT had a higher risk of breast fibrosis and retraction (OR 3.58, 95% CI 1.024-12.526, p = 0.046) and breast edema (OR 6, 95% CI 2.077-17.335, p = 0.001) compared to IORT-f, but a lower risk of seroma compared to IORT-b (OR 0.36, 95% CI 0.166-0.785, p = 0.01). The BIBCQ scores showed a better outcome in arm concerns with IORT-f (-3.3) vs. IORT-b (-1.3, p = 0.002) and EBRT (-1.7, p = 0.006), although biased by the lower rate in axillary dissections. Return to daily activities occurred after 70.6 days with EBRT vs. 41 days with IORT-f (p < 0.0001) and 53.3 days with IORT-b (p = 0.07), without any effect of age or axillary dissection.

CONCLUSION

IORT could reduce adverse effects, allowing faster resumption of job and houseworks.

RNAi screens identify CHD4 as an essential gene in breast cancer growth

Epigenetic regulation plays an essential role in tumor development and epigenetic modifiers are considered optimal potential druggable candidates. In order to identify new breast cancer vulnerabilities and improve therapeutic chances for patients, we performed in vivo and in vitro shRNA screens in a human breast cancer cell model (MCF10DCIS.com cell line) using epigenetic libraries. Among the genes identified in our screening, we deeply investigated the role of Chromodomain Helicase DNA binding Protein 4 (CHD4) in breast cancer tumorigenesis. CHD4 silencing significantly reduced tumor growth in vivo and proliferation in vitro of MCF10DCIS.com cells. Similarly, in vivo breast cancer growth was decreased in a spontaneous mouse model of breast carcinoma (MMTV-NeuT system) and in metastatic patient-derived xenograft models. Conversely, no reduction in proliferative ability of non-transformed mammary epithelial cells (MCF10A) was detected. Moreover, we showed that CHD4 depletion arrests proliferation by inducing a G0/G1 block of cell cycle associated with up-regulation of CDKN1A (p21). These results highlight the relevance of genetic screens in the identification of tumor frailties and the role of CHD4 as a potential pharmacological target to inhibit breast cancer growth.

Sentinel node biopsy in ductal carcinoma in situ of the breast: Never justified?

Sentinel lymph node biopsy for ductal carcinoma in situ (DCIS) of the breast is not standard of care. However, nodal involvement for DCIS patients is reported. Aim of our study was to identify preoperative features predictive of nodal involvement in DCIS patients. We have retrospectively reviewed 175 patients with a preoperative diagnosis of DCIS following a vacuum-assisted breast biopsy, and undergoing surgery with sentinel node biopsy. Variables distribution was compared between patients upstaged to invasive cancer at final pathology and patients with a confirmed DCIS, and between positive vs negative sentinel node patients. Univariate and multivariate analyses were performed for risk of a positive node. Lymph node biopsy was positive in 13 (7.4%) patients, with 8 (61.5%) macrometastases and 5 (38.5%) micrometastases. In these patients, Breast Imaging Reporting and Data System (BI-RADS) index >4 (OR 4.69, 95% CI 1.282-17.224, P = .02), lesion extension ≥20 mm (OR 4.25, 95% CI 1.255-14.447, P = .02), multifocal disease (OR 4.12, 95% CI 0.987-17.174, P = .05), comedo type (OR 3.54, 95% CI 1.044-11.969, P = .04), and upstaging (OR 4.56, 95% CI 1.080-19.249, P = .04) were all predictive of nodal involvement, although upstaging could not be predicted preoperatively. By multivariate analysis, the only independent factor predictive for positive sentinel node was multifocal disease (OR 5.14, 95% CI 1.015-26.066, P < .05). A preoperative diagnosis of DCIS, also including advanced biopsy systems such as vacuum-assisted breast biopsy, may be not always sufficient to exclude patients from sentinel node biopsy. DCIS patients with associated BI-RADS >4, lesion extension ≥20 mm, comedo type, and above all multifocal disease should be considered for axillary evaluation.

Active music therapy approach for stroke patients in the post-acute rehabilitation

Guidelines in stroke rehabilitation recommend the use of a multidisciplinary approach. Different approaches and techniques with music are used in the stroke rehabilitation to improve motor and cognitive functions but also psychological outcomes. In this randomized controlled pilot trial, relational active music therapy approaches were tested in the post-acute phase of disease. Thirty-eight hospitalized patients with ischemic and hemorrhagic stroke were recruited and allocated in two groups. The experimental group underwent the standard of care (physiotherapy and occupational therapy daily sessions) and relational active music therapy treatments. The control group underwent the standard of care only. Motor functions and psychological aspects were assessed before and after treatments. Music therapy process was also evaluated using a specific rating scale. All groups showed a positive trend in quality of life, functional and disability levels, and gross mobility. The experimental group showed a decrease of anxiety and, in particular, of depression (p = 0.016). In addition, the strength of non-dominant hand (grip) significantly increased in the experimental group (p = 0.041). Music therapy assessment showed a significant improvement over time of non-verbal and sonorous-music relationships. Future studies, including a greater number of patients and follow-up evaluations, are needed to confirm promising results of this study.

Is there a role for homeopathy in breast cancer surgery? A first randomized clinical trial on treatment with Arnica montana to reduce post-operative seroma and bleeding in patients undergoing total mastectomy

AIM

This study aimed to evaluate the benefits of Arnica montana on post-operative blood loss and seroma production in women undergoing unilateral total mastectomy by administering Arnica Montana 1000 Korsakovian dilution (1000 K).

MATERIALS AND METHODS

From 2012 to 2014, 53 women were randomly assigned to A. montana or placebo and were followed up for 5 days. The main end point was the reduction in blood and serum volumes collected in drainages. Secondary end points were duration of drainage, a self-evaluation of pain, and the presence of bruising or hematomas.

RESULTS

The per-protocol analysis revealed a lower mean volume of blood and serum collected in drainages with A. montana (-94.40 ml; 95% confidence interval [CI]: 22.48-211.28; P = 0.11). A regression model including treatment, volume collected in the drainage on the day of surgery, and patient weight showed a statistically significant difference in favor of A. montana (-106.28 ml; 95% CI: 9.45-203.11; P = 0.03). Volumes collected on the day of surgery and the following days were significantly lower with A. montana at days 2 (P = 0.033) and 3 (P = 0.0223). Secondary end points have not revealed significant differences.

CONCLUSIONS

A. montana 1000 K could reduce post-operative blood and seroma collection in women undergoing unilateral total mastectomy. Larger studies are needed with different dilutions of A. montana to further validate these data.

Dual modulation of MCL-1 and mTOR determines the response to sunitinib

Most patients who initially respond to treatment with the multi-tyrosine kinase inhibitor sunitinib eventually relapse. Therefore, developing a deeper understanding of the contribution of sunitinib's numerous targets to the clinical response or to resistance is crucial. Here, we have shown that cancer cells respond to clinically relevant doses of sunitinib by enhancing the stability of the antiapoptotic protein MCL-1 and inducing mTORC1 signaling, thus evoking little cytotoxicity. Inhibition of MCL-1 or mTORC1 signaling sensitized cells to clinically relevant doses of sunitinib in vitro and was synergistic with sunitinib in impairing tumor growth in vivo, indicating that these responses are triggered as prosurvival mechanisms that enable cells to tolerate the cytotoxic effects of sunitinib. Furthermore, higher doses of sunitinib were cytotoxic, triggered a decline in MCL-1 levels, and inhibited mTORC1 signaling. Mechanistically, we determined that sunitinib modulates MCL-1 stability by affecting its proteasomal degradation. Dual modulation of MCL-1 stability at different dose ranges of sunitinib was due to differential effects on ERK and GSK3β activity, and the latter also accounted for dual modulation of mTORC1 activity. Finally, comparison of patient samples prior to and following sunitinib treatment suggested that increases in MCL-1 levels and mTORC1 activity correlate with resistance to sunitinib in patients.

Abstract B43: PILOT: a patient-oriented in vivo functional platform to identify new lethalities and optimize cancer treatment

Large-scale genomics efforts have provided the opportunity to access a comprehensive catalog of genetic alterations in multiple cancers. However, it has also become apparent that very few driver mutations are emerging and as a consequence of that, limited opportunities exist to target mutated oncogenic proteins. It is imperative therefore to develop alternative approaches to therapy that can leverage the selective vulnerabilities of tumor cells resulting from the engagement of abnormal pathway connectivity. These can be best exploited in vivo, in a context that is closer to the environment tumors strive in. To identify new relevant actionable dependencies we have developed PILOT (Patient-oriented In vivo Lethality to Optimize Treatment), a loss-of-function in vivo platform for rapid identification of potential therapeutic targets in Patient-Derived Xenografts (PDXs). By optimizing primary tumor explant and expansion, determination of tumor-initiating cell frequency trough retroviral-mediated transduction, in vivo RNA interference screens, next-generation sequencing and analytic pipelines, we have been able to establish a comprehensive “patient-centric” approach oriented towards the identification of the highest priority genetic targets in specific clinico-pathological and mutational settings. So far, the main limitation for the systematic exploitation of in vivo functional genomics systems to elucidate patient vulnerabilities in the PDX models come from the limited number of human cells contributing to tumor establishment in a transplantation setting. The frequency of these tumors initiating cells (TICs) is commonly estimated by time-consuming limiting dilution assays and may consistently vary between different tumor origins. With this in mind, we have integrated in our platform a system based on scrambled barcoded libraries that allows to directly assess the required coverage of screening libraries in each model and adjust the RNAi screens for this factor. Our coverage study demonstrated to be a powerful tool to identify the minimal number of cells/barcode required to sustain a complex library in PDX models and at the same time a step forward to personalize the in vivo screening patient-by-patient. As proof of concept, we applied our PILOT platform to systematically interrogate context-specific epigenetic dependencies in pancreatic ductal adenocarcinoma (PDAC). In addition to the well-known genetic alterations (KRAS, TP53, CDKN2A/p16, SMAD4), some epigenetic mechanisms demonstrated to play a central role in PDAC progression and some of them could intriguingly represent new points of vulnerability, due to the low-frequency of mutation (ex. collateral or synthetic lethality). Our screening system utilized fully annotated low-passage PDAC xenografts and a lentiviral library of pooled shRNAs targeting 230 potentially “druggable” epigenetic regulators adjusted for the coverage study in each PDX. Hairpin-associated molecular barcodes were quantified by massively parallel sequencing and clustered according to their depletion or enrichment in comparison to a control population before transplantation. To date, we have completed a total of 5 in vivo screens using diverse PDAC xenograft models and, applying our comprehensive mutational and functional data analytics pipeline, we have developed a high-throughput validation scheme to triage “hits” that emerge from each screen. Focusing on epigenetic regulators, we identified WDR5, a core member of the COMPASS histone H3 Lys4 (H3K4) MLL (1-4) methyltransferase complex, as a top tumor maintenance hit required across multiple PDAC tumors and associated with the presence of G1-checkpoint alterations (p53 or p16). Mechanistically, WDR5 functions to sustain proper execution of DNA replication in PDAC cells, as previously suggested by replication stress studies involving MLL1, a critical ATR substrate, and c-Myc, also found to interact with WDR5. We indeed demonstrated that the WDR5-Myc interaction is critical for this replicative function and protects the PDAC cells from the excessive DNA damage accumulation and mitotic catastrophe. Intriguingly, this checkpoint function executed by the WDR5-Myc axis to protect the S-phase seems to be an addiction of the cancer cells, that have more active replication forks to stabilize in order to sustain the abnormal proliferative burst. To confirm this new cancer-associated lethality, we demonstrated that normal cells display less sensitivity to this replication checkpoint in virtue of their proficient G1-checkpoints and reduced time spent in S-phase compared to cancer cells. So, our PILOT platform was able to illuminate new therapeutic vulnerabilities that can be rapidly evaluated in the clinic through the development of WDR5-Myc inhibitors. In the near future, we plan to extend this platform in syngeneic mouse models, where one can probe the effects of target inhibition in the context of an intact immune response and in the presence of immune checkpoint activators, and in association with approved drugs, to identify new therapeutic options for recalcitrant tumor populations.

Citation Format: Alessandro Carugo, Giannicola Genovese, Sahil Seth, Luigi Nezi, Angelo Cicalese, Daniela Bossi, Johnathon L. Rose, Andrea Viale, Luisa Lanfrancone, Timothy P. Heffernan, Giulio F. Draetta. PILOT: a patient-oriented in vivo functional platform to identify new lethalities and optimize cancer treatment. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B43.

Abstract A28: Challenging new epigenetic vulnerabilities in human metastatic melanoma PDXs

Metastatic melanoma is one of the most aggressive cancers, refractory to most of the current therapies in its late stage. Melanoma is characterized by a strong molecular heterogeneity, and patients can be stratified in different subtypes according to genetic alterations. Despite the approval of new targeted drugs, patient treatment produces only partial responses and frequent and rapid relapses, mostly due to increased resistance. Mounting evidence highlights the necessity to better stratify melanomas on the basis of altered molecular pathways and to define new specific and effective tailored therapies. Our main goal is the genetic and functional characterization of metastatic melanomas aimed to generate new predictive and prognostic biomarkers and to identify new potential “druggable” candidates involved in melanoma progression.

We have generated a series of human-in-mouse melanoma models, by xeno-transplantation of a cohort of human melanoma samples in immune-compromised mice. Our patient-derived xenografts (PDXs) faithfully recapitulate the heterogeneity of the original tumors at phenotypic and genetic level. Taking advantage of our model, we performed the first in vivo genetic screen on patient-derived tumors, using metastatic NRAS- and BRAF-mutant melanomas and targeting chromatin genes (~240). Our screens revealed unprecedented numerosity of tumor drivers (~50% of tested genes) and unexpected functional heterogeneity among patients (~60 drivers per tumor; &lt;15% in common). Tumor drivers, however, were not activated by somatic mutations in the same patients. Several genes have been validated in vivo and then characterized in vitro on primary cultures derived from the patients' cells. We analysed underlying molecular mechanisms of one of the identified drivers, the Histone-lysine N-methyltransferase KMT2D, and showed that it promotes tumorigenesis by dysregulating a subset of transcriptional enhancers and genes involved in cell migration.

Citation Format: Daniela Bossi, Angelo Cicalese, Ivan Gaetano Dellino, Lucilla Luzi, Simona Punzi, Carolina D'Alesio, Elena Cavallaro, Saverio Minucci, PierGiuseppe Pelicci, Luisa Lanfrancone. Challenging new epigenetic vulnerabilities in human metastatic melanoma PDXs. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A28.

In Vivo Functional Platform Targeting Patient-Derived Xenografts Identifies WDR5-Myc Association as a Critical Determinant of Pancreatic Cancer

Current treatment regimens for pancreatic ductal adenocarcinoma (PDAC) yield poor 5-year survival, emphasizing the critical need to identify druggable targets essential for PDAC maintenance. We developed an unbiased and in vivo target discovery approach to identify molecular vulnerabilities in low-passage and patient-derived PDAC xenografts or genetically engineered mouse model-derived allografts. Focusing on epigenetic regulators, we identified WDR5, a core member of the COMPASS histone H3 Lys4 (H3K4) MLL (1-4) methyltransferase complex, as a top tumor maintenance hit required across multiple human and mouse tumors. Mechanistically, WDR5 functions to sustain proper execution of DNA replication in PDAC cells, as previously suggested by replication stress studies involving MLL1, and c-Myc, also found to interact with WDR5. We indeed demonstrate that interaction with c-Myc is critical for this function. By showing that ATR inhibition mimicked the effects of WDR5 suppression, these data provide rationale to test ATR and WDR5 inhibitors for activity in this disease.

In Vivo Genetic Screens of Patient-Derived Tumors Revealed Unexpected Frailty of the Transformed Phenotype

The identification of genes maintaining cancer growth is critical to our understanding of tumorigenesis. We report the first in vivo genetic screen of patient-derived tumors, using metastatic melanomas and targeting 236 chromatin genes by expression of specific shRNA libraries. Our screens revealed unprecedented numerosity of genes indispensable for tumor growth (∼50% of tested genes) and unexpected functional heterogeneity among patients (<15% in common). Notably, these genes were not activated by somatic mutations in the same patients and are therefore distinguished from mutated cancer driver genes. We analyzed underlying molecular mechanisms of one of the identified genes, the Histone-lysine N-methyltransferase KMT2D, and showed that it promotes tumorigenesis by dysregulating a subset of transcriptional enhancers and target genes involved in cell migration. The assembly of enhancer genomic patterns by activated KMT2D was highly patient-specific, regardless of the identity of transcriptional targets, suggesting that KMT2D might be activated by distinct upstream signaling pathways.

SIGNIFICANCE

Drug targeting of biologically relevant cancer-associated mutations is considered a critical strategy to control cancer growth. Our functional in vivo genetic screens of patient-derived tumors showed unprecedented numerosity and interpatient heterogeneity of genes that are essential for tumor growth, but not mutated, suggesting that multiple, patient-specific signaling pathways are activated in tumors. Cancer Discov; 6(6); 650-63. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 561.

Abstract 1701: Identification of epigenetic modifiers able to suppress growth of pancreatic ductal adenocarcinoma: A patient-oriented in vivo functional platform

We have seen great advances in our knowledge of the genetic regulation of various cancers in recent years, thanks in large part to large-scale genome sequencing efforts. As we catalogue and characterize the genomic aberrations associated with cancers with increasing detail and accuracy, we are faced with the challenge of having to cull bystanders from biologically active drivers and establish relevant disease context in which these drivers are rate-limiting. To address this challenge, we have adapted a loss-of-function screening approach to function in the context of an intact tumor microenvironment using patient-derived tumors that more faithfully recapitulate the human disease compared to established cell lines. Due to the genetic heterogeneity between human tumors, we have integrated independent screening approaches in a flexible platform for the interrogation of patient-derived samples as well as GEM models in exactly the same experimental conditions. The goal of this platform is to identify context-specific genetic vulnerabilities and translate these findings into drug discovery opportunities. As proof of concept, we developed an in vivo loss-of-function screen to systematically interrogate epigenetic dependencies in pancreatic ductal adenocarcinoma (PDAC). The screening system utilizes tumor cells isolated from low-passage xenograft tissue and a lentiviral library of pooled shRNAs targeting 230 “druggable” epigenetic regulators. The custom-designed shRNA library (10 shRNAs per gene) was engineered with unique molecular barcodes that allow quantitation of each clone by deep sequencing. To date, we have completed a total of 5 in vivo screens using diverse PDAC models that have informed on novel epigenetic dependencies. So far, the main limitation for the systematic exploitation of in vivo loss-of-function screens come from the limited number of human cells contributing to tumor establishment in a transplantation setting. The frequency of these tumor initiating cells (TICs) is commonly estimated by limiting dilution assays and may consistently vary between tumor origins. With this in mind, we have integrated in our platform a system based on scrambled barcoded libraries that allow to directly assess the required coverage of screening libraries in each model. Our coverage study demonstrated to be a powerful tool to identify the minimal number of cells/barcode required to sustain a complex library and at the same time a step forward to personalize the in vivo screening patient by patient. We optimized a comprehensive data analytics pipeline and developed a high-throughput validation scheme to triage “hits” that emerge from each screen. The most potent “hits” have been enrolled in both functional and clinico-pathological validation studies to determine the highest priority targets for this devastating disease. Results from these studies will be presented.

Note: This abstract was not presented at the meeting.

Citation Format: Alessandro Carugo, Giannicola Genovese, Sahil Seth, Luigi Nezi, Johnathon L. Rose, Andrea Viale, Piergiorgio F. Pettazzoni, Angelo Cicalese, Daniela Bossi, Wantong Yao, Jason B. Fleming, Luisa Lanfrancone, Timothy P. Heffernan, Giulio F. Draetta. Identification of epigenetic modifiers able to suppress growth of pancreatic ductal adenocarcinoma: A patient-oriented in vivo functional platform. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1701. doi:10.1158/1538-7445.AM2015-1701

Functional characterization of a novel FGFR1OP-RET rearrangement in hematopoietic malignancies

The RET (REarranged during Transfection) receptor tyrosine kinase is targeted by oncogenic rearrangements in thyroid and lung adenocarcinoma. Recently, a RET (exon 12) rearrangement with FGFR1OP [fibroblast growth factor receptor 1 (FGFR1) oncogene partner] (exon 12) was identified in one chronic myelomonocytic leukemia (CMML) patient. We report the molecular cloning and functional characterization of a novel FGFR1OP (exon 11)-RET (exon 11) gene fusion event (named FGFR1OP-RET), mediated by a reciprocal translocation t(6; 10)(q27; q11), in a patient affected by primary myelofibrosis (PMF) with secondary acute myeloid leukemia (AML). The FGFR1OP-RET fusion protein displayed constitutive tyrosine kinase and transforming activity in NIH3T3 fibroblasts, and induced IL3-independent growth and activation of PI3K/STAT signaling in hematopoietic Ba/F3 cells. FGFR1OP-RET supported cytokine-independent growth, protection from stress and enhanced self-renewal of primary murine hematopoietic progenitor and stem cells in vitro. In vivo, FGFR1OP-RET caused a spectrum of disease phenotypes, with >50% of mice showing a fatal myeloproliferative disorder (MPD). Other phenotypes were leukemia transplantable in secondary recipients, dramatic expansion of the mast cell lineage, and reduction of repopulating activity upon lethal irradiation. In conclusion, FGFR1OP-RET chimeric oncogenes are endowed with leukemogenic potential and associated to myeloid neoplasms (CMML and PMF/AML).

Persistent hiccup after surgical resection of a brainstem arteriovenous malformation: a case successfully treated with gabapentin during rehabilitation. Case report

Persistent hiccup rarely occurs during rehabilitation, but its management can prove to be very difficult, particularly in presence of associated dysphagia, requiring longer hospitalization and higher risk of severe clinical complications. We present a case of persistent hiccup after surgical resection of a brainstem arteriovenous malformation successfully treated with gabapentin during rehabilitation.

Usefulness of BFB/EMG in facial palsy rehabilitation

OBJECTIVE

To analyze and to compare the recovery and the development of synkinesis in patients with idiopathic facial palsy (Bell's palsy) following treatment with two methods of rehabilitation, kinesitherapy (KT) and biofeedback/EMG (BFB/EMG).

STUDY DESIGN

Retrospective cases--series review.

METHODS

Seventy-four patients with Bell' palsy were clinically evaluated within 1 month from onset of palsy and at 12 months after palsy (House scale and synkinesis evaluation). Electromyography (EMG) and Electroneurography (ENG) were performed about 4 weeks after palsy to better evaluate functional abnormalities due to facial nerve lesion. The patients followed two different protocols for rehabilitation: the first 32 patients were treated with therapeutic exercises performed by therapists (KT group), the latter 42 patients were treated using BFB/EMG methods (BFB group) with inhibition of synkinetic movement as the primary goal.

RESULTS

KT and BFB patients were evaluated for clinical and neurophysiological characteristics before rehabilitative treatment. BFB patients showed better clinical recovery and minor synkinesis than KT patients.

CONCLUSIONS

BFB/EMG seems to be more useful than KT in Bell's palsy treatment. This could be due to the fact that BFB/EMG gives more accurate information than KT on muscle activation with better modulation in voluntary recruitment of motor unit.

An uncommon cause of corrosive esophageal injury

We present an unusual case of corrosive esophageal injury following liquid glue ingestion. The endoscopic findings were tissue sloughing and blackened appearance of the esophagogastric junction, due to caustic esophageal injuries following ingestion of glue containing toluene.

A redundant oncogenic potential of the retinoic receptor (RAR) alpha, beta and gamma isoforms in acute promyelocytic leukemia

Alterations of the retinoic acid receptor (RAR)alpha locus are found in 100% of acute promyelocytic leukemia patients, where chromosomal translocations generate the promyelocytic leukemia (PML)-RARalpha chimeric protein. Here, we have investigated the biological properties of the other RAR isoforms (RARbeta and RARgamma), through the generation and characterization of artificial PML-RAR'x' fusion proteins. Surprisingly, we found that all of the RAR isoforms share an identical oncogenic potential in vitro, thus implying that the selection of the RARalpha locus in leukemia patients must occur--rather than through functional differences among the various RAR isoforms-as the consequence of the nuclear architecture of the different RAR loci.

The methyl-CpG binding protein MBD1 is required for PML-RARalpha function

PML-RARalpha induces a block of hematopoietic differentiation and acute promyelocytic leukemia. This block is based on its capacity to inactivate target genes by recruiting histone deacetylase (HDAC) and DNA methyltransferase activities. Here we report that MBD1, a member of a conserved family of proteins able to bind methylated DNA, cooperates with PML-RARalpha in transcriptional repression and cellular transformation. PML-RARalpha recruits MBD1 to its target promoter through an HDAC3-mediated mechanism. Binding of HDAC3 and MBD1 is not confined to the promoter region but instead is spread over the locus. Knock-down of HDAC3 expression by RNA interference in acute promyelocytic leukemia cells alleviates PML-RAR-induced promoter silencing. We further demonstrate that retroviral expression of dominant-negative mutants of MBD1 in hematopoietic precursors compromises the ability of PML-RARalpha to block their differentiation and thus restored cell differentiation. Our results demonstrate that PML-RARalpha functions by recruiting an HDAC3-MBD1 complex that contributes to the establishment and maintenance of the silenced chromatin state.

MOZ-TIF2 inhibits transcription by nuclear receptors and p53 by impairment of CBP function

Chromosomal rearrangements associated with acute myeloid leukemia (AML) include fusions of the genes encoding the acetyltransferase MOZ or MORF with genes encoding the nuclear receptor coactivator TIF2, p300, or CBP. Here we show that MOZ-TIF2 acts as a dominant inhibitor of the transcriptional activities of CBP-dependent activators such as nuclear receptors and p53. The dominant negative property of MOZ-TIF2 requires the CBP-binding domain (activation domain 1 [AD1]), and coimmunoprecipitation and fluorescent resonance energy transfer experiments show that MOZ-TIF2 interacts with CBP directly in vivo. The CBP-binding domain is also required for the ability of MOZ-TIF2 to extend the proliferative potential of murine bone marrow lineage-negative cells in vitro. We show that MOZ-TIF2 displays an aberrant nuclear distribution and that cells expressing this protein have reduced levels of cellular CBP, leading to depletion of CBP from PML bodies. In summary, our results indicate that disruption of the normal function of CBP and CBP-dependent activators is an important feature of MOZ-TIF2 action in AML.

A functional assessment methodology for alcohol dependent patients undergoing rehabilitative treatments

PURPOSE

We propose a functional assessment approach for patients with alcoholic dependence of working age undergoing aerobic training. The background is the WHO indication (ICIDH-2) to use measurable 'activities' as a means to assess the individual 'participation' in social life which also implies work capacity. Defining sustainable energetic levels for the individual is an important issue for both the quantification of an effective training and the evaluation of possible improvements following training.

METHODS

Fifty-six 'alcohol dependent' patients, as defined by DSM IV (Diagnostic and Statistical Manual of Mental Disorders), admitted to our Unit in a 16 month-period participated in the study. Eighteen healthy subjects served as controls (Group C). Out of all the 56 patients, 33 (Group A) underwent an aerobic training and 23 subjects (Group N) underwent the same pharmacological and psychological therapy but without aerobic training. Patients were assigned to the treatment (A) or no treatment (N) group according to a 'quasi-experimental' design (i.e. temporal selection criteria). The evaluation protocol consisted of submaximal symptom-limited tests. The tests consisted of bouts of 'basic' activities (walking, lifting, arm-work) to be performed at different intensities. We estimated the total energetic work (TW) performed in the tests by means of formulas available in the literature. The maximal energetic intensity (EI) reached during the tests was also estimated and expressed in MET (multiple of the basal metabolism).

RESULTS

Significant differences in work capacity were observed between patients and healthy subjects at baseline. Group A significantly increased TW after rehabilitation, while Group N did not increment their performance at the re-test.

CONCLUSIONS

The proposed approach could be useful in the functional assessment of deconditioned subjects with alcohol dependence in working age, and could monitor the changes in work capacity following training.

A baker's yeast mutant (fil1) with a specific, partially inactivating mutation in adenylate cyclase maintains a high stress resistance during active fermentation and growth

The initiation of fermentation in the yeast Saccharomyces cerevisiae is associated with a rapid drop in stress resistance. This is disadvantageous for several biotechnological applications, e.g. the preparation of freeze doughs. We have isolated mutants in a laboratory strain which are deficient in fermentation-induced loss of stress resistance ('fil' mutants) using a heat shock selection protocol. We show that the fil1 mutant contains a mutation in the CYR1 gene which encodes adenylate cyclase. It causes a change at position 1682 of glutamate into lysine and results in a tenfold drop in adenylate cyclase activity. The fil1 mutant displays a reduction in the glucose-induced cAMP increase, trehalase activation and loss of heat resistance. Interestingly, the fil1 mutant shows the same growth and fermentation rate as the wild type strain, as opposed to other mutants with reduced activity of the cAMP pathway. Introduction of the fil1 mutation in the vigorous Y55 strain and cultivation of the mutant under pilot scale conditions resulted in a yeast that displayed a higher freeze and drought resistance during active fermentation compared to the wild type Y55 strain. These results show that high stress resistance and high fermentation activity are compatible biological properties. Isolation of fil-type mutations appears a promising avenue for development of industrial yeast strains with improved stress resistance during active fermentation.

Red cell physiology

The erythrocyte, the ultimate product of mammalian erythroid maturation, appears as a highly specialized and, paradoxically, a very simplified cell. In fact it lacks a nucleus and the intracellular organelles are essentially designed to transport oxygen from the outer environment to respiring tissues through the sophisticated functional properties of intraerythrocytic hemoglobin. In this respect, since oxygen transport is such a vital process, the red cell has often been considered, in an excess of oversimplification, as merely a "biological bag' enveloping a viscous solution of concentrated hemoglobin and containing only those few enzymes which are needed to maintain the cell functionally active. However, within the cell a number of different processes are contemporaneously going on, hemoglobin acts as an oxygen and carbon dioxide transporter, glycolysis and the pentose phosphate shunt are devoted to the production of ATP and NADPH, respectively, and membrane organization provides the cell with a good deformability, allowing it to cross narrow splenic capillaries and channels without any appreciable damage for several weeks of activity. All these processes are, indeed, highly integrated and concur to define a complex scenery centered on the oxygenation-deoxygenation cycle of hemoglobin. Within this emerging scheme, hemoglobin appears to display, besides the basic function of oxygen transport, several other biological functions which are driven by the oxygen-linked conformational transition and whose relative importance, in the economy of the cell and of the organism, is not easy to qualify. Some of these aspects are described and discussed.

Hemolytic anemias due to disorders of red cell membrane skeleton

During the past 10 years, knowledge of the composition, function and supramolecular assembly of the red cell membrane has been greatly expanded by progress in molecular and cell biology. Detailed information on the organization of membrane cytoskeletal proteins and their molecular characterization has allowed us to correlate a number of protein abnormalities with clinical symptoms that are peculiar to hereditary hemolytic anemias (HHA). In particular, three general principles emerge that can help us to understand the pathogenetic mechanisms of HHA: (a) protein-protein and protein-lipid interactions greatly influence the correct assembly of the membrane skeleton; (b) the red blood cell (RBC) membrane skeleton mostly determines the shape (discocyte), deformability (rheologic properties) and durability (half-life and resistence to shear stress) of the erythrocytes; (c) changes in cytoskeletal composition and/or organization can produce alterations in all of the above properties, and therefore they are responsible for the onset of the hemolytic damage.

The effect of magnesium on glycolysis of permeabilized Ehrlich ascites tumor cells

We have previously observed that extracellular Mg2+ influences the phosphofructokinase (PFK) activity of intact Ehrlich Ascites tumour cells (EATC). In this study we have investigated the mechanism by which Mg2+ modulates this key glycolytic enzyme in EATC made permeable to the cation by either digitonin or dextran sulphate. Results showed that when Mg2+ is freely permeable to the cytosol, the in vivo PFK activity, calculated as FDP/G6P ratio, is not increased as it is in intact cells. We also observed that in permeabilized cells Mg2+ determines the increase of glucose 6 phosphate (G6P), fructose 1,6 bisphosphate (FDP) and lactate production. We hypothesize that extracellular Mg2+ regulates PFK and glycolysis in these neoplastic cells not by entering the cytosol but by a specific interaction with the plasma membrane.

Magnesium in normal and neoplastic cell proliferation: state of the art on in vitro data

Information about the involvement of Mg2+ in all biochemical processes that participate in cell proliferation is reviewed in order to define the role of this divalent cation in normal and pathological growth. The lack of conclusive data about cell Mg2+ homeostasis does not suggest any definitive model for its role in the control of cell proliferation. On the other hand, new important information about its absolute requirement in crucial steps of cell activation that can, beside other functions, trigger cell division, strongly support the involvement of Mg2+ in the control of cell proliferation. Studies on the growth of cells in vitro, however, while confirming the indispensible requirement for Mg2+ in extracellular media, do not completely clarify the mechanism(s) or the exact phase/point of the cell cycle where Mg2+ exerts its regulation. Furthermore, the observation that tumour cells grown in culture are influenced by external divalent cations confirms the involvement of Mg2+ in cancer as well as in normal cell proliferation. The proposed explanations (theories, hypotheses) are described and discussed.

The effect of Mg2+ upon 6-phosphofructokinase activity in Ehrlich ascites tumor cells in vivo

The effect of Mg2+ addition to intact Ehrlich ascites tumor cells (EATC) has been investigated. A decrease of glucose 6-phosphate (G6P) content and an increase of fructose 1,6-diphosphate (FDP) content are detected in glucose utilizing EATC incubated with increasing Mg2+ concentrations (from 0 to 5.0 mM). The strong enhancement of FDP/G6P ratio is taken as evidence for in vivo stimulation of phosphofructokinase 1 (PFK) (ATP:D-fructose-6-phosphate 1-phosphotransferase; EC 2.7.1.11). A similar effect can be observed when glucose is replaced by fructose as the glycolytic substrate. Stimulation of PFK is paralleled by substantial depletion of ATP. Cytochalasin B prevents the observed phenomena. Cell total Mg increases by about 15% when EATC are incubated with 5 mM Mg2+. The overall data show that extracellular Mg2+ may modulate glycolytic flux in EATC in vivo. Implications and significance of these phenomena in the regulation of cancer cell metabolic features are discussed.

Impairment of microsomal calcium sequestration activity upon superoxide dismutase depletion in rat liver

We have studied the Ca2+-accumulation activity of microsomal vesicles isolated from the liver of rats held for from 2 to 8 weeks on a copper-deficient diet. With this treatment that deeply modifies fatty acid composition, microsomal membranes show progressively lower Ca2+ sequestration. The activity can be fully restored upon physiological copper supply to the depleted animals. The determination of kinetic parameters of microsomal Ca2+ uptake shows that copper deficiency affects mainly the apparent velocity, leaving unaffected the apparent affinity of the pump for Ca2+. Many similarities were found between this model and the Morris hepatomas with different growth rate. The data support the hypothesis that the oxidative stress imposed on the cell by the loss of superoxide dismutase can influence many cell features, with different implications in the regulation of several biological and biochemical functions.