Management of Esophago-Gastric Junction Carcinoma: A Narrative Multidisciplinary Review

Esophagogastric junction (EGJ) carcinoma represents a specific site of disease, given the opportunities for multimodal clinical care and management and the possibilities of combined treatments. It encompasses various clinical subgroups of disease that are heterogeneous and deserve different treatments; therefore, the guidelines have progressively evolved over time, considering the evidence provided by clinical trials. The aim of this narrative review was to summarize the main evidence, which orientates the current guidelines, and to collect the main ongoing studies to address existing gray areas.

PANHER study: a 20-year treatment outcome analysis from a multicentre observational study of HER2-positive advanced breast cancer patients from the real-world setting

Background:

The evolution of therapeutic landscape of human epidermal growth factor receptor-2 (HER2)-positive breast cancer (BC) has led to an unprecedented outcome improvement, even if the optimal sequence strategy is still debated. To address this issue and to provide a picture of the advancement of anti-HER2 treatments, we performed a large, multicenter, retrospective study of HER2-positive BC patients.

Methods:

The observational PANHER study included 1,328 HER2-positive advanced BC patients treated with HER2 blocking agents since June 2000 throughout July 2020. Endpoints of efficacy were progression-free survival (PFS) and overall survival (OS).

Results:

Patients who received a first-line pertuzumab-based regimen showed better PFS (p < 0.0001) and OS (p = 0.004) than those receiving other treatments. Median PFS and mOS from second-line starting were 8 and 28 months, without significant differences among various regimens. Pertuzumab-pretreated patients showed a mPFS and a mOS from second-line starting not significantly affected by type of second line, that is, T-DM1 or lapatinib/capecitabine (p = 0.80 and p = 0.45, respectively). Conversely, pertuzumab-naïve patients receiving second-line T-DM1 showed a significantly higher mPFS compared with that of patients treated with lapatinib/capecitabine (p = 0.004). Median OS from metastatic disease diagnosis was higher in patients treated with trastuzumab-based first line followed by second-line T-DM1 in comparison to pertuzumab-based first-line and second-line T-DM1 (p = 0.003), although these data might be partially influenced by more favorable prognostic characteristics of patients in the pre-pertuzumab era. No significant differences emerged when comparing patients treated with ‘old’ or ‘new’ drugs (p = 0.43), even though differences in the length of the follow-up between the two cohorts should be taken into account.

Conclusion:

Our results confirmed a relevant impact of first-line pertuzumab-based treatment and showed lower efficacy of second-line T-DM1 in trastuzumab/pertuzumab pretreated, as compared with pertuzumab-naïve patients. Our findings may help delineate a more appropriate therapeutic strategy in HER2-positive metastatic BC. Prospective randomized trials addressing this topic are awaited.

Is the hospital Safety Walkround effective to control the risk of contagion during COVID-19 pandemic?

Background

The Safety Walk Round (SWR) is a risk assessment technique designed to decrease adverse events and improve workers attitudes about safety culture through visits and interviews about safety of care. A new field of application could be the safety requirements that hospitals have to guarantee during the Covid-19 pandemic. Our study aimed to investigate the efficacy of SWR on identifying and solving the critical issues that can increase the risk of SARS-CoV-2 infection in three Italian hospitals.

Materials and Methods

The project was developed during the first wave of SARS-Cov-2 pandemic, from May to July 2020, it involved 3 hospitals in Turin: Traumatology and Orthopaedic Centre, Paediatric Hospital Regina Margherita and Sant'Anna Hospital (obstetric and gynaecological hospital). Pre-triage services and outpatient waiting rooms were identified as areas at higher risk of crowding and potential non-compliance with anti-contagion rules. The first round consisted of observations focused on hands sanitation, safety social distance, PPE correct use. Than the workers of the observed areas were interviewed. Thanks their participation, the critical issues about patient safety and the potential resolutions were identified. A second round was realized to verify the implementation of the planned actions and their effectiveness in solving the issues.

Results

A total of 4907 moments were observed and the 9,1% of them was at risk of contagion. During the interviews 23 critical issues and their possible resolutions were identified. A total of 14 critical issues were solved, 4 partially solved and 5 were build environmental problems and cannot be solved. The 77% of total were completely solved, excluding built environment issues.

Conclusions

SWR project was effective in involving health workers in safety promotion activities, sharing informations and improving trust between hospital managers and operators and spreading new skills about safety culture in Covid-19 pandemic contest.

Key messages

SWR was effective in a pandemic context. During the emergency, the front line staff were enthusiastic about the method and felt listened and guided.This has contributed to achieving the aim of safety.

The study showed that SWR is a useful tool for hospital infection control. It also showed that the SWR method can be used in a time of constant change that requires adaptability like a pandemic.

Assessment of Duration and Effects of 3 vs 6 Months of Adjuvant Chemotherapy in High-Risk Stage II Colorectal Cancer: A Subgroup Analysis of the TOSCA Randomized Clinical Trial

Importance

The addition of oxaliplatin to the standard 6-month fluorouracil-based adjuvant chemotherapy in stage II colorectal cancer has been reported to reduce the risk of relapse although it does not increase survival. The Three or Six Colon Adjuvant (TOSCA) trial compared 3 months with 6 months of adjuvant fluoropyrimidine and oxaliplatin-based chemotherapy in patients with stage III colon cancer. The utility remains unknown.

Objective

To assess the noninferiority and toxic effects of 3 vs 6 months of FOLFOX (fluorouracil, leucovorin, and oxaliplatin) or CAPOX (capecitabine plus oxaliplatin) adjunct chemotherapy among patients with high-risk stage II resected colorectal cancer enrolled in the TOSCA trial.

Design, Setting, and Participants

The TOSCA study was a noninferiority phase 3 randomized clinical trial conducted from June 2007 to March 2013 in 130 Italian centers. Included patients had resected colorectal cancer located 12 cm from the anal verge by endoscopy or above the peritoneal reflection at surgery. In this preplanned study assessing the per-protocol population, 5-year relapse-free survival was evaluated in 1254 patients with high-risk stage II resected colorectal cancer who had received adjuvant FOLFOX (fluorouracil, leucovorin, and oxaliplatin) or CAPOX (capecitabine plus oxaliplatin).

Interventions

Patients were originally randomized (1:1) in the TOSCA trial to receive 3 months (experimental group) or 6 months (control) of standard doses of FOLFOX or CAPOX at the discretion of the treating physician.

Main Outcome and Measures

A hazard ratio of at least 1.2 between the 3-month and 6-month chemotherapy groups was set to reject the null hypothesis of noninferiority.

Results

Overall, 1254 patients (mean [SD] age, 62.4 [9.8] years; 565 women [45.1%]) with clinical high-risk stage II resected colorectal cancer were analyzed at a median follow-up of 62 months (interquartile range, 53-71) months. Of them, 301 patients (24.0%) had pT4N0M0 tumors, and the remaining 953 patients (76.0%) had high-risk pT3N0M0 tumors; 776 patients (61.9%) received FOLFOX and 478 (38.1%) received CAPOX. The 5-year relapse-free survival was 82.2% for the 3-month arm and 88.2% for the 6-month arm, with an estimated hazard ratio of 1.41 (95% CI, 1.05-1.89; P = .86 for noninferiority). For CAPOX, the 5-year relapse-free survival was similar in the 2 arms (difference, 0.76% favoring the 6-month arm; 95% CI, -6.28% to 7.80%), whereas for FOLFOX, the difference was pronounced: 8.56% in favor of the longer-duration arm (95% CI, 3.45%-13.67%). Nevertheless, the test for an interaction between duration and regimen was not statistically significant. Neurotoxicity was approximately 5 times lower in the shorter duration arm than in the longer duration arm.

Conclusions and Relevance

In the 3-month arm, the treatment was significantly less toxic than in the 6-month arm. Noninferiority was not shown for 5-year relapse-free survival. However, a possible regimen effect was observed, suggesting that either 3 months of CAPOX or 6 months of FOLFOX therapy can be used whenever an oxaliplatin doublet is indicated for treatment of patients with stage II colorectal cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT0064660.

Loss of HER2 and decreased T-DM1 efficacy in HER2 positive advanced breast cancer treated with dual HER2 blockade: the SePHER Study

BACKGROUND

HER2-targeting agents have dramatically changed the therapeutic landscape of HER2+ advanced breast cancer (ABC). Within a short time frame, the rapid introduction of new therapeutics has led to the approval of pertuzumab combined with trastuzumab and a taxane in first-line, and trastuzumab emtansine (T-DM1) in second-line. Thereby, evidence of T-DM1 efficacy following trastuzumab/pertuzumab combination is limited, with data from some retrospective reports suggesting lower activity. The purpose of the present study is to investigate T-DM1 efficacy in pertuzumab-pretreated and pertuzumab naïve HER2 positive ABC patients. We also aimed to provide evidence on the exposure to different drugs sequences including pertuzumab and T-DM1 in HER2 positive cell lines.

METHODS

The biology of HER2 was investigated in vitro through sequential exposure of resistant HER2 + breast cancer cell lines to trastuzumab, pertuzumab, and their combination. In vitro experiments were paralleled by the analysis of data from 555 HER2 + ABC patients treated with T-DM1 and evaluation of T-DM1 efficacy in the 371 patients who received it in second line. Survival estimates were graphically displayed in Kaplan Meier curves, compared by log rank test and, when possibile, confirmed in multivariate models.

RESULTS

We herein show evidence of lower activity of T-DM1 in two HER2+ breast cancer cell lines resistant to trastuzumab+pertuzumab, as compared to trastuzumab-resistant cells. Lower T-DM1 efficacy was associated with a marked reduction of HER2 expression on the cell membrane and its nuclear translocation. HER2 downregulation at the membrane level was confirmed in biopsies of four trastuzumab/pertuzumab-pretreated patients. Among the 371 patients treated with second-line T-DM1, median overall survival (mOS) from diagnosis of advanced disease and median progression-free survival to second-line treatment (mPFS2) were 52 and 6 months in 177 patients who received trastuzumab/pertuzumab in first-line, and 74 and 10 months in 194 pertuzumab-naïve patients (p = 0.0006 and 0.03 for OS and PFS2, respectively).

CONCLUSIONS

Our data support the hypothesis that the addition of pertuzumab to trastuzumab reduces the amount of available plasma membrane HER2 receptor, limiting the binding of T-DM1 in cancer cells. This may help interpret the less favorable outcomes of second-line T-DM1 in trastuzumab/pertuzumab pre-treated patients compared to their pertuzumab-naïve counterpart.

[Organization and management of clinical-care pathways at the Regina Margherita Hospital in Turin during Covid-19 emergency]

The Covid-19 pandemic significantly increased the workload for the Italian Health Service. There is few information in the literature on the pediatric population and on the management of pediatric hospitals. The aim of this article is to describe the management of healthcare services during Covid-19 emergency in Regina Margherita Children's Hospital. The Regina Margherita Children's Hospital is specialized in the prevention, diagnosis and treatment of pediatric diseases. About 1000 health worker work in this Hospital and 278 hospitalization places are available.

Predicting difficult discharge from surgical wards: a cohort study in an Italian sample

Background

Poor discharge planning (DP) can increase costs for European hospitals and worsen patient's experience. Validated scores are used in internal medicine to identify clinical or social difficulties in discharges upon admission but there is a lack of such a tool in the surgical context. This study aims to detect early predictors of difficult discharge.

Methods

Socio-demographic and clinical data from 15,165 surgical Hospital Discharge Records (SDOs) of the Molinette hospital of Turin, including an additional pre-surgery evaluation of social vulnerabilites from a subgroup of 388 patients, were collected between 2017 and 2019. Outcomes were length of stay (LOS), discharge destination (home, Long Term Care - LTC). Descriptive analysis and multivariable regressions were performed.

Results

52.3% of patients were male and the median age was 61 (IQR 22). Median LOS was 6 days (IQR 6) but 15 (IQR 30) for patients discharged to LTC. 18.7% were admitted through the Emergency Department (ED) with a median LOS of 7 (IQR 10). 17.6% of the subsample declared living alone. Linear regression showed associations between discharge to LTC, admission through ED, diagnosis of neoplasia and a longer LOS (Bs 10.76, 5.21 and 2.57 respectively, p &lt; 0.001). Logistic regression showed associations between admission by ED, age and discharge to LTC (OR 1.77 and 1.02 respectively, p &lt; 0.001). Preliminary analysis of the subsample did not show any new association with social vulnerabilities, but 98.2% attended elective surgery and thus probably had time to prepare for discharge.

Conclusions

Surgery LOSs are extremely diversified among patients. This study identified several predictors of difficult discharge, mainly admission through ED, discharge to LTC and diagnosis of neoplasia, suggesting difficulties handling an unexpected event by patients' relatives. Further studies gathering patients' data at admission are required in order to develop a predictive tool useful for European hospitals.

Key messages

Clinical (cancer) and social (sudden event, no housing solutions) factors can determine a difficult discharge for European patients and should be investigated to anticipate discharge planning. Elective surgery patients seem less prone to social vulnerabilities (e.g. living alone), probably because relatives have time to prepare, while ED patients often need help in the discharge process.

Transition of care from paediatric to adult age for rare chronic disorders: an Italian experience

Background

Transition of care represents the transfer from child to adult care. An effective transition maintains continuity of care and presents better clinical outcomes. Thanks to improved survivorship of chronic paediatric patients to adulthood, this process has assumed growing relevance. Aim of the study was to evaluate quality and effectiveness of transition of care model of one of the biggest Hospitals of Northern Italy, that has organised a common structured model, differentiated according to patients' clinical and social complexity.

Methods

The sample consisted of patients with chronic rare diseases transited within the Hospital in the years 2016-2019. To analyse the evolution of all pathologies, for each patient the medical record was consulted; questionnaires were then administered to patients to investigate their illness perception and quality of life.

Results

The average age at transition of the retrospective study patients was 19.8±4.7 years. For most disorders, 100% of patients made the first post-transition visit. More than 90% of patients who did not make further post-transition visits were patients with Neurofibromatosis 1. Only 7 out of 18 patients with NF1 continued their treatment to the indicated specialist. One-year drop-out was 13%. Regarding the perception of one's own illness, 78% of respondents consider their health status from good to excellent, but more than 30% of respondents believe not to have currently adequate psychological and social support.

Conclusions

Transition of care represents an important phase in chronic diseases management. The proposed model assures a multidisciplinary approach, involving all specialists of both paediatric and adult teams. Preliminary data were positive and showed how this model could be an example for other institutions in Europe. Anyway, the transition model might be still be improved. Our data underlined the importance of a complete taking charge, with peculiar attention to psychological and social support.

Key messages

The study shows to the European Healthcare Providers the importance of a personalized planning of transition of care, that considers the complexity of clinical situation and concomitant social issues. A successful strategy of transition of care requires a multidisciplinary approach, that guarantees a complete taking charge, with peculiar attention to psychological and social support.

Clinical Practice Guidelines for Diagnosis, Treatment and Follow-Up of Exocrine Pancreatic Ductal Adenocarcinoma: Evidence Evaluation and Recommendations by the Italian Association of Medical Oncology (AIOM)

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related death in women (7%) and the sixth in men (5%) in Italy, with a life expectancy of around 5% at 5 years. From 2010, the Italian Association of Medical Oncology (AIOM) developed national guidelines for several cancers. In this report, we report a summary of clinical recommendations of diagnosis, treatment and follow-up of PDAC, which may guide physicians in their current practice. A panel of AIOM experts in upper gastrointestinal cancer malignancies discussed the available scientific evidence supporting the clinical recommendations.

Impact of BMI on HER2+ metastatic breast cancer patients treated with pertuzumab and/or trastuzumab emtansine. Real-world evidence

Body mass index (BMI) is a main indicator of obesity and its association with breast cancer is well established. However, little is known in the metastatic setting, especially in HER2-positive patients. We assessed the influence of BMI on clinical outcomes of patients treated with pertuzumab and/or trastuzumab emtansine (T-DM1) for HER2+ metastatic breast cancer (mBC). BMI was addressed as a categorical variable, being classified on the basis of the following ranges, that is, 18.5-24.9, 25-29.9, and 30.0-34.9, namely, normal weight, overweight, and Class I obesity. The outcomes chosen were progression-free survival to first-line chemotherapy (PFS1) and overall survival (OS). Overall (N = 709), no impact of BMI was observed on PFS1 (p = .15), while BMI ≥ 30 was associated with worse OS (p = .003). In subjects who progressed to first line (N = 575), analyzing data across PFS1 quartiles and strata of disease burden, BMI predicted lower PFS1 in patients within the I PFS1 quartile and with the lowest disease burden (p = .001). Univariate analysis showed a detrimental effect of BMI ≥ 30 on OS for women within the I PFS1 quartile (p = .03). Results were confirmed in multivariate analysis. According to PFS1 quartiles a higher percentage of patients with high BMI and low disease burden progressed within 6 months of therapy. The effect of BMI on prognosis was also confirmed in multivariate analysis of OS for overall population. In our cohort, a BMI ≥ 30 correlated with worse OS in patients with HER2+ mBC who received pertuzumab and/or T-DM1 but had no impact on PFS to first line. BMI predicted worse I PFS1 quartile.

Predictive Impact of Mucinous Tumors on the Clinical Outcome in Patients with Poorly Differentiated, Stage II Colon Cancer: A TOSCA Subgroup Analysis

BACKGROUND

Although American Society of Clinical Oncology and European Society for Medical Oncology guidelines have identified the negative prognostic factors that clinicians have to consider when treating their patients with stage II colon cancer (CC), the role of histological subtype is controversial.

SUBJECTS, MATERIALS, AND METHODS

The randomized, multicenter, phase III TOSCA trial compared 3 versus 6 months of fluoropyrimidine-oxaliplatin adjuvant chemotherapy in 3,759 patients with high-risk stage II or stage III CC. The objective of this substudy was to evaluate the influence of histological subtypes on the impact of the treatment duration of adjuvant chemotherapy in terms of relapse-free survival (RFS) and overall survival (OS) in 85 mucinous adenocarcinoma (MUC) and 389 nonmucinous adenocarcinoma (NMUC) patients with high-risk stage II, grade 3 CC.

RESULTS

A significant interaction between treatment duration and histology was observed in both RFS (p = .027) and OS (p = .017). In the subgroup of patients with MUC, worse RFS (adjusted hazard ratio [HR], 3.95; 95% confidence interval [CI], 1.03-15.17; p = .045) and OS (HR, 9.56; 95% CI, 1.14-79.98; p = .037) were detected for patients treated in the 3-month arm. No statistically significant differences were found in the subgroup of patients with NMUC.

CONCLUSION

Patients with MUC, grade 3, stage II CC require special attention and may need 6 months of oxaliplatin-based chemotherapy. Larger studies are required to assess the combined use of histology and other prognostic/predictive factors to define the administration of chemotherapy in patients with stage II CC and to improve their prognosis.

IMPLICATIONS FOR PRACTICE

Although ASCO and ESMO guidelines define the prognostic factors for patients with stage II colon cancer to establish the use of adjuvant chemotherapy, the influence of histological subtypes is controversial in this population. This study underscores that patients with grade 3 mucinous adenocarcinomas may need adjuvant chemotherapy with oxaliplatin and fluoropyrimidines for a duration of 6 months rather than 3 months.

Distinct HR expression patterns significantly affect the clinical behavior of metastatic HER2+ breast cancer and degree of benefit from novel anti-HER2 agents in the real world setting

We analyzed data from 738 HER2‐positive metastatic breast cancer (mbc) patients treated with pertuzumab‐based regimens and/or T‐DM1 at 45 Italian centers. Outcomes were explored in relation to tumor subtype assessed by immunohistochemistry (IHC). The median progression‐free survival at first‐line (mPFS1) was 12 months. Pertuzumab as first‐line conferred longer mPFS1 compared to other first‐line treatments (16 vs. 9 months, p = 0.0001), regardless of IHC subtype. Median PFS in second‐line (mPFS2) was 7 months, with no difference by IHC subtype, but it was more favorable with T‐DM1 compared to other agents (7 vs. 6 months, p = 0.03). There was no PFS2 gain in patients with tumors expressing both hormonal receptors (HRs; p = 0.17), while a trend emerged for tumors with one HR (p = 0.05). Conversely, PFS2 gain was significant in HRs‐negative tumors (p = 0.04). Median overall survival (mOS) was 74 months, with no significant differences by IHC subtypes. Survival rates at 2 and 3 years in patients treated with T‐DM1 in second‐line after pertuzumab were significantly lower compared to pertuzumab‐naïve patients (p = 0.01). When analyzed by IHC subtype, the outcome was confirmed if both HRs or no HRs were expressed (p = 0.02 and p = 0.006, respectively). Our results confirm that HRs expression impacts the clinical behavior and novel treatment‐related outcomes of HER2‐positive tumors when treatment sequences are considered. Moreover, multivariate analysis showed that HRs expression had no effect on PFS and OS. Further studies are warranted to confirm our findings and clarify the interplay between HER2 and estrogen receptor pathways in HER2‐positive (mbc) patients.

What's new?

About half of breast cancers positive for human epidermal growth factor (HER2) also express hormone receptors but the impact of hormone receptor status on the success of HER2‐directed treatments is not fully explored. Here the authors retrospectively assessed tumor behavior and treatment outcomes in 738 women with HER2+ metastatic breast cancer treated with new generation anti‐HER2 agents. Distinct hormone receptor expression patterns significantly affected the progression free and overall survival, justifying further studies to define optimal treatment regimens and the interplay between hormone receptor and HER2 signaling.

The unmet need for oncofertility preservation in women: Results of a survey by different oncological specialists in Lazio, Italy

In recent years, we have witnessed a growing interest in the prevention of the loss of reproductive efficacy in young women as a result of cancer or its treatments. Indeed, recent studies have shown that loss of fertility impacts deeply on young women and sometimes may be even more stressful than the cancer diagnosis itself. In fact, the risk of treatment-associated infertility and premature menopause is a major concern for patients. Nevertheless, the approach to fertility preservation in women diagnosed with cancer is far from being standardized, and counseling strategies are poorly adopted in clinical practice. In Italy, the federal structure of public health makes it difficult to refer patients to local referral centers experienced in fertility preservation. In particular, a need exists to identify oncologists in the Lazio region specialized in fertility preservation and those facilities who are able to counsel patients regarding their sexuality. For these reasons, the Lazio section of Italian Association of Medical Oncology has led an oncofertility and oncosexuality survey to assess deficiencies in the path to start fertility preservation procedures and to help patients with cancer-related sexual problems. In total, 273 healthcare providers participated in the survey. Overall, the participants had a low interest in their patients' infertility problems, which led to a poor referral of patients to fertility preservation centers. This behavior demonstrated by healthcare providers is attributed to the necessity to rapidly start oncological treatments, the lack of knowledge of referral centers, and the little experience in tackling the subject with the patients. The interviewees also recognize communication difficulties related to lack of information on issues, absence of rehabilitations paths, and embarrassment.

Abstract P4-13-07: SEQUERPLUS: A multicenter real practice observational study investigating the endocrine-based (E) therapies sequential approach in hormonal receptor positive (HR+) HER2 negative (-) metastatic breast cancer (MBC)

Background: Despite the sequential E therapy is recognized as the preferred approach for HR+/HER2- MBC, no data from clinical trials support the choice between the different sequential strategies.

Methods: In this retrospective study descriptive statistics are reported using the median (Interquartile range, IQR) or frequency. Progression Free Survival (PFS) curves were estimated with the Kaplan-Meier method and compared with the log-rank test. Analysis were performed by SPSS version 21.0 (SPSS Inc., Chicago, IL).

Results: From January 2006 to December 2017, 240 patients (pts) with HR+/HER2- MBC receiving at least two consecutive E therapies as first approach were selected from 12 italian cancer centers. The median age at the time of metastasis onset was 63.5 (IQR: 55-72.5) years; 184 (76.7%) pts were in menopausal status; 38 (16%) had de novo stage IV disease and the remaining 202 (84%) had recurrent BC with a median time of 78 months (5-396 months). At the beginning of MBC diagnosis, 148 (62%) pts had a single site of distant disease, 108 (45%) of whom had bone only disease and 45 (18.8%) presented visceral involvement too. The aromatase inhibitor (AI) was chosen as I-line therapy in 146 (60.9%) pts, followed by Fulvestrant (F) in 62 (25.8%) pts; the alternative I-line options were everolimus-exemestane (Eve-Exe), tamoxifene (T), Palbociclib (P)+AI and F+AI in 13 (5.4%), 14 (5.8%), 1 (0.4%) and 4 (1.7%) pts, respectively. The most favourite II-line option resulted F for 111 (46.2%) pts while the Eve-Exe combination was chosen in 70 (29.2%) pts, AI in 30 (12.5%) pts; T, AI+F, P+F and antiprogestincwere administered in 4 (1.7%), 4 (1.7%), 19 (7.9%) and 2 (0.8%) pts, respectively. For I and II-line, the AI followed by F (40%) and F followed by Eve-Exe (18%) were the most common sequential therapeutic approaches; the several alternative options were scanty used (in less than 10%). The median Progression-Free Survival (PFS) from first and second-line E therapies resulted 15.7 (95% CI 13.3-18.1) and 10.3 months (95% CI 8.7-11.9), respectively. Among 194 pts with disease progression after second-line E therapy, 87 (44.8%) received further E therapies with a median PFS 9.4 months (95% CI 7.9-10.9). The remaining 70 (29.2%) pts was treated with palliative chemotherapy. Interestingly, the median Overall Survival (OS) was even longer for pts receiving more lines of E therapies compared to the group with earlier introduction of chemotherapy (204.3 vs 92.8; p=0.007).

Finally, in the subgroup analyses a longer PFS benefit was observed in pts with disease recurrence over 12 months from initial diagnosis (38.1 vs 30.3 months p=0.04) and limited sites of disease involvement at the time of MBC diagnosis (37.6 vs 28.3 months, p=0.03)

Conclusions: The sequential use in first and second-line setting of E therapies for HR+/HER2- MBC improves median PFS up to 32.3 months. According to real practice experience the optimal sequences could be AIs followed by F and F followed by Eve-Exe. A role for these compounds should be redefined in the light of recently introduction of CDK 4/6 inhibitors in combination with AIs or F for the first or later lines.

Citation Format: Fabi A, Giannarelli D, Botticelli A, Scagnoli S, Pellegrino A, Fabbri A, Corsi D, Magri V, Pizzuti L, Paris I, Bruni V, Pace R, Lanzetta G, Stani S, Moscetti L, Marchetti P, Piesco G, Cognetti F, Rossi V. SEQUERPLUS: A multicenter real practice observational study investigating the endocrine-based (E) therapies sequential approach in hormonal receptor positive (HR+) HER2 negative (-) metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-13-07.

Palbociclib plus endocrine therapy in HER2 negative, hormonal receptor-positive, advanced breast cancer: A real-world experience

Data from 423 human epidermal growth factor receptor 2-negative (HER2-), hormone receptor-positive (HR+) advanced breast cancer (aBC) patients treated with palbociclib and endocrine therapy (ET) were provided by 35 Italian cancer centers and analyzed for treatment outcomes. Overall, 158 patients were treated in first line and 265 in second/later lines. We observed 19 complete responses and 112 partial responses. The overall response rate (ORR) was 31% (95% confidence interval [CI], 26.6-35.4) and clinical benefit was 52.7% (95% CI, 48-57.5). ORR was negatively affected by prior exposure to everolimus/exemestane ( p = 0.002) and favorably influenced by early line-treatment ( p < 0.0001). At 6 months, median progression-free survival was 12 months (95% CI, 8-16) and median overall survival was 24 months (95% CI, 17-30). More favorable outcomes were associated with palbociclib in early lines, no visceral metastases and no prior everolimus/exemestane. The main toxicity reported was neutropenia. Our results provide further support to the use of palbociclib with ET in HER2-, HR+ aBC. Differences in outcomes across patients subsets remain largely unexplained.

A multicenter REtrospective observational study of first-line treatment with PERtuzumab, trastuzumab and taxanes for advanced HER2 positive breast cancer patients. RePer Study

We carried out a retrospective observational study of 264 HER2-positive advanced breast cancer (ABC) patients to explore the efficacy of first-line treatment with pertuzumab/trastuzumab/taxane in real-world setting. Survival data were analyzed by Kaplan Meier curves and log rank test. Median follow-up, length of pertuzumab/trastuzumab/taxane treatment and of pertuzumab, trastuzumab maintenance were 21, 4 and 15 months, respectively. The response rate was 77.3%, and the clinical benefit rate 93.6%. Median progression-free survival (mPFS) was 21 months, and median overall survival (mOS) was not reached. When comparing patients by trastuzumab-pretreatment, similar PFS were observed, although a longer OS was reached in trastuzumab-naïve patients (p = 0.02). Brain metastases at baseline and their development in course of therapy were associated with significantly shorter PFS (p = 0.0006) and shorter OS, although at a not fully statistically relevant extent (p = 0.06). The addition of maintenance endocrine therapy (ET) to pertuzumab/trastuzumab maintenance was associated with longer PFS (p = 0.0001), although no significant differences were detected in OS (p = 0.31). Results were confirmed by propensity score analysis (p = 0.003 and p = 0.46, respectively). In multivariate models, longer PFS was related to lower Performance Status (PS) (p = 0.07), metastatic stage at diagnosis (p = 0.006) and single metastatic site (p < 0.0001). An OS advantage was observed with lower PS (p < 0.0001), single metastatic site (p = 0.004), no prior exposure to trastuzumab (p = 0.004) and response to pertuzumab-based treatment (p = 0.003). Our results confirm that trastuzumab/pertuzumab/taxane is the standard of care as first-line treatment of patients with HER2-positive ABC even in the real-world setting. Moreover, the double-maintenance therapy (HER2 block and ET) is strongly recommended when feasible.

Abstract CT088: Efficacy of anti-EGFR rechallenge in RAS and BRAF wt metastatic colorectal cancer: Clinical and translational results of the phase II CRICKET study by GONO

Introduction CRICKET (NCT02296203) trial was designed to investigate the activity of the rechallenge with cetuximab (cet) and irinotecan (iri) as third-line treatment in RAS and BRAF wild-type mCRC patients (pts) with acquired resistance to 1st-line cet- and iri-based therapy. Recent data highlighted the clonal evolution and heterogeneity of acquired resistance to anti-EGFR treatments, and suggested the role of liquid biopsy as a reliable tool to track molecular events in circulating tumor DNA (ctDNA) and to properly inform treatment choices.

Materials and Methods: The primary endpoint was response rate (RR) according to RECIST v1.1. Setting p0 = 5%, and p1 = 20%, with 1-sided-α and β errors of 0.05 and 0.20, 27 patients were required. Null hypothesis would have been rejected if RECIST response had been observed in at least 4 patients. Main eligibility criteria included: RAS/RAF wild-type status in tissue samples; acquired resistance to 1st-line cet and iri-based regimen with at least RECIST partial response (PR), 1st-line PFS ≥6 months, and progression (PD) within 4 weeks after the last administration of cet; 2nd-line bevacizumab and oxaliplatin-based regimen. 3rd-line cet + iri was administered until PD. Liquid biopsies were collected at the rechallenge baseline. ctDNA was analyzed with ddPCR for specific RAS and BRAF mutations (mut), and then by means of ultra-deep next-generation sequencing (NGS) with Ion Torrent S5 XL (Thermo Fisher Scientific, Waltham, MA, USA).

Results: Between January 2015 and June 2017, 28 pts were enrolled in 9 centers. The primary endpoint was met. Six pts had PRs (RR: 21.4%) that were not confirmed in two consecutive evaluations in two cases, and 9 achieved disease stabilization (Disease Control Rate: 53.6%). Three patients were not evaluable for RECIST response. RAS mut were found in liquid biopsies collected at the rechallenge baseline in 12 (48%) out of 25 evaluable patients. No BRAF or PI3KCA mut were found. As shown in table 1, no RAS mut were detected in samples from patients who achieved a confirmed PR.

Conclusion:  Rechallenge with cet + iri is active in some RAS and BRAF wild-type mCRC patients with acquired resistance to 1st-line iri- and cet-based therapy. Candidate patients' selection may be improved by treating only those who do not bear any RAS mut or other less frequent resistance mechanisms in ctDNA at the rechallenge baseline.

Partially funded by Merck Serono SpA.

Table 1PatientsRAS status on ctDNAObjective Response#1Wild-typeConfirmed PR#2KRAS G12DPD#3Wild-typeConfirmed PR#4Wild-typePD#5KRAS G12DSD#6Wild-typePD#7Wild-typeSD#9Wild-typeConfirmed PR#10Wild-typeUnconfirmed PR#11Wild-typePD#12KRAS G12DPD#13KRAS G12VPD#15NRAS Q61LSD#16Wild-typeSD#17KRAS G12V/ Q61HPD#18KRAS G12VPD#19Wild-typeConfirmed PR#21KRAS G12DSD#22KRAS G12VSD#23KRAS G12VPD#24KRAS G12DUnconfirmed PR#25KRAS G12DSD#26Wild-typeSD#27Wild-typePD#28Wild-typeSD

Citation Format: Daniele Rossini, Chiara Cremolini, Marzia Del Re, Sara Lonardi, Adele Busico, Eleonora Rofi, Silvio Ken Garattini, Emiliano Tamburini, Emanuela Dell'Aquila, Domenico Corsi, Francesca Bergamo, Carlo Barone, Gianluca Masi, Francesca Pucci, Monica Cattaneo, Filippo Pietrantonio, Federica Perrone, Giuseppe Tonini, Daniele Santini, Alfredo Falcone. Efficacy of anti-EGFR rechallenge in RAS and BRAF wt metastatic colorectal cancer: Clinical and translational results of the phase II CRICKET study by GONO [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT088.

Phase III study with FOLFIRI + cetuximab versus FOLFIRI + cetuximab followed by cetuximab alone in RAS and BRAF WT mCRC

The optimal duration and intensity of first-line therapy in metastatic colorectal cancer patients once they have achieved an objective response is controversial. In a molecularly selected RAS and BRAF wild-type (wt) population, this concern is amplified. Once disease control has been achieved with a combination therapy including an anti-EGFR antibody, further exposure both to cytotoxic drugs and targeted therapy might result only in increased toxicity. In unresectable metastatic RAS and BRAF wt colorectal cancer patients, a deintensified therapy could represent a valuable option that might preserve quality of life. We designed a study to compare FOLFIRI/cetuximab to FOLFIRI/cetuximab for eight cycles followed by cetuximab alone in first-line treatment of RAS and BRAF (wt) metastatic colorectal cancer patients.

Early Integration of Palliative Care in Oncology Practice: Results of the Italian Association of Medical Oncology (AIOM) Survey

BACKGROUND

Early integration of palliative care in oncology practice ("simultaneous care", SC) has been shown to provide better care resulting in improved quality-of-life and also survival. We evaluated the opinions of Italian Association of Medical Oncology (AIOM) members.

PATIENTS AND METHODS

A 37-item questionnaire was delivered to 1119 AIOM members. Main areas covered were: social, ethical, relational aspects of disease and communication, training, research, organizational and management models in SC. Three open questions explored the definition of Quality of Life, Medical Oncologist and Palliative Care.

RESULTS

Four hundred and forty-nine (40.1%) medical oncologists returned the questionnaires. Forty-nine percent stated they address non-curability when giving a diagnosis of metastatic tumor, and 43% give the information only to patients who clearly ask for it. Fifty-five percent say the main formative activity in palliative medicine came from attending meetings and 90% agree that specific palliative care training should be part of the core curriculum in oncology. Twenty-two percent stated they consulted guidelines for symptom management, 45% relied upon personal experience and 26% make a referral to a palliative care specialist. Seventy-four percent were in favor of more research in palliative medicine. An integration between Units of Oncology and Palliative Care Services early in the course of advanced disease was advocated by 86%. Diverse and multifaceted definitions were given for the concepts of Quality of Life, Palliative Care and Medical Oncologist.

CONCLUSION

SC is felt as an important task, as well as training of medical oncologists in symptom management and research in this field.

Evaluation of relapse-free survival in T3N0 colon cancer: the role of chemotherapy, a multicentric retrospective analysis

Background

Adjuvant chemotherapy (AC) in Stage II Colon Cancer (CC) is still under debate. Choice should be based on patients and disease characteristics. According to guidelines AC should be considered in high-risk T3N0 patients. No data are available for better option in low-risk patients. The aim of the study is to retrospectively evaluate relapse-free survival (RFS) and disease-free survival (DFS) according to treatment received in T3N0 CC.

Methods

RFS and DFS are evaluated with Kaplan-Meier method. Multivariate Cox proportional hazard model was developed using stepwise regression, enter limit and remove limit were p = 0.10 and p = 0.15, respectively.

Results

834 patients with T3N0 CC were recruited. Median age was 69 (29–93), M/F 463/371, 335 low-risk patients (40.2%), 387 high-risk (46.4%), 112 unknown (13.4%); 127 (15.2%) patients showed symptoms at diagnosis. Median sampled lymph nodes were 15 (1–76); 353 (42.3%) patients were treated with AC. Median follow up was 5 years (range 3–24). The 5-years RFS was 78.4% and the 5-years DFS was 76.7%. At multivariate analysis symptoms, lymph nodes, and adjuvant chemotherapy were prognostic factors for RFS. AC is prognostic factor for all endpoints.

In low-risk group 5-years RFS was 87.3% in treated patients and 74.7% in non-treated patients (p 0.03); in high-risk group was respectively 82.7% and 71.4% (p 0.005).

Conclusions

Data confirmed the role of known prognostic factors and suggest the relevance of adjuvant chemotherapy also in low-risk stage II T3N0 CC patients. However, the highest risk in low-risk subgroup should be identified to be submitted to AC.

Local effects of atherosclerotic plaque on arterial distensibility

Hypertension, diabetes, and hypercholesterolemia are characterized by a reduction in arterial distensibility and by accelerated atherosclerosis. Whether arterial stiffening is an inherent feature of these conditions or just the consequence of the atherosclerotic clinical or subclinical lesions is not known, however. Our aim was to obtain information on this issue by directly measuring, in humans, arterial distensibility both at the site of an atherosclerotic lesion and at the proximal normal site. In 10 patients (8 men; mean+/-SEM age, 65.2+/-3.4 years) affected by monolateral hemodynamic significant internal carotid artery stenosis, we measured arterial distensibility (Wall Track System; PIE Medical) bilaterally, both at the internal carotid artery and at the common carotid artery level. In the common carotid artery, measurements were made 3 cm below the bifurcation. In the affected internal carotid artery, measurements were made at the plaque shoulder (wall thickness of 2 mm). Measurements were made in the contralateral internal carotid artery at a symmetrical level. Arterial wall thickness was measured in the same site of arterial distensibility. Arterial distensibility was less in the internal than in the common carotid artery, with a marked reduction at the plaque internal carotid artery level compared with the corresponding contralateral site (-45%, P<0.01). It was also less, however, in the common carotid artery branching into the atherosclerotic internal carotid artery than in the contralateral common carotid artery (-25%, P<0.05). Wall thickness was similar in the 2 common carotid arteries and obviously greater in the affected internal carotid artery than in the contralateral artery. Arterial distensibility was markedly less in the internal carotid artery where there was a plaque compared with the intact contralateral internal carotid artery; it was also less, however, in the common carotid artery of the affected side in comparison with the contralateral common carotid artery. This provides evidence that the effect of a plaque on arterial mechanical properties is not limited to the actual plaque site but rather extends to a considerable degree in a proximal direction.

Identification of Blood Erythroid Markers Useful in Revealing Erythropoietin Abuse in Athletes

Recombinant human erythropoietin (rEpo) is being used with increasing frequency by endurance athletes to improve aerobic potential. Although rEpo administration has been banned by the International Olympic Committee, no methods are available to unequivocally detect its abuse in sports. Prompted by these considerations, we evaluated the main hematological and biochemical modifications measured in the blood of 18 volunteers upon rEpo administration. Different rEpo regimens, iron, folic acid, and vitamin B12 administration did not significantly modify the percentage increase in hematocrit. However, a significant decrease in circulating ferritin (fr) and an increase in the soluble transferrin receptor (sTfr) were not found in athletes receiving low (30 IU/kg) doses of rEpo. Thus, an increase in the sTfr/fr ratio cannot be used as an indicator of rEpo abuse, at least when the hormone is administered at low concentrations. In contrast, the amounts of beta-globin mRNA detected by quantitative competitive (RT)-PCR in whole blood samples significantly increased above the threshold levels in all of the treatments investigated. Taken together, these data suggest that hematocrit value, reticulocyte count, soluble transferrin receptor content, and concentration of beta-globin mRNA, when included in a new multiparametric formula, can detect rEpo abuse in 57.5% of the samples examined with a confidence interval of 99.99%. Thus, the method reported in this paper could significantly improve the tests currently available, which in similar experiments allowed the detection of rEpo abuse in only 7.6% of the samples examined.

Unscheduled cyclin B expression and p34 cdc2 activation in T lymphocytes from HIV-infected patients

OBJECTIVE

To study the role of cell cycle regulation during HIV infection by investigating in vivo and in vitro cyclin B and p34 cdc kinase expression.

METHODS

Cyclin B expression was analysed by Western blot in CD4 and CD8 cells from 25 HIV-infected patients and 24 uninfected individuals. In eight patients, a sequential analysis was performed after initiation of antiretroviral therapy (ART), and correlations with CD4 cell count and HIV viremia were studied. Sequential changes in cyclin B expression and p34 cdc kinase expression and activity were also studied in lymphocytes activated in vitro with phytohaemagglutinin (PHA).

RESULTS

Lymphocytes from untreated HIV-infected patients demonstrate persistent in vivo overexpression of cyclin B in both CD4 and CD8 cell subpopulations. When cells are stimulated to proliferate in vitro, biochemical events that characterize the entrance into the cell cycle [ornithine decarboxylase (ODC) activity, interleukin 2 production, interleukin 2 alpha-chain receptor (IL-2R, CD25) expression, total protein synthesis, total DNA synthesis] show similar timing and sequence in lymphocytes from HIV-infected and uninfected individuals. However, in peripheral blood lymphocytes (PBL) from HIV-infected patients, cyclin B and p34 cdc kinase show premature expression during the cell cycle. Both in vivo cyclin B overexpression and in vitro unscheduled cyclin B expression were almost completely reversed 2-4 weeks after initiation of effective ART.

CONCLUSION

Increased and unscheduled expression of cyclin B and p34 cdc kinase is consistently observed in CD4 and CD8 cells from HIV-infected patients, both in vivo and after in vitro mitogenic stimulation. These alterations correlate with the level of viremia and may provide a link between the perturbation of lymphocyte proliferative homeostasis and the exaggerated propensity towards apoptosis.

Alteration of alpha-spectrin ubiquitination due to age-dependent changes in the erythrocyte membrane

Mammalian red blood cell alpha-spectrin is ubiquitinated in vitro and in vivo [Corsi, D., Galluzzi, L., Crinelli, R., Magnani, M. (1995) J. Biol. Chem. 270, 8928-8935]. This process shows a cell age-dependent decrease, with senescent red blood cells having approximately one third of the amount of ubiquitinated alpha-spectrin found in young cells. In-vitro ubiquitination of alpha-spectrin was dependent on the source of the red cell membranes (those from older cells are less susceptible to ubiquitination than those from younger cells), on the source of ubiquitin-conjugating enzymes (those from older cells catalyze the process at a reduced rate compared to those from younger cells) and on the ubiquitin isopeptidase activity (which decreases during red cell ageing). However, once alpha-spectrin has been extracted from the membranes of young or old red blood cells, it is susceptible to ubiquitination to a similar extent regardless of source. This suggests that it is the membrane architecture, and not spectrin itself, that is responsible for the age-dependent decline in ubiquitination. Furthermore, spectrin oligomers, tetramers and dimers are also equally susceptible to ubiquitination. As spectrin ubiquitination occurs on domains alphaIII and alphaV of alpha-spectrin, and domain alphaV contains the nucleation site for the association of the alpha- and beta-spectrin chains, alterations in ubiquitination during red cell ageing could affect the stability and deformability of the erythrocyte membrane.

Protein degradation and apoptotic death in lymphocytes during Fiv infection: activation of the ubiquitin-proteasome proteolytic system

The movement of a cell through the sequential phases of apoptosis is accompanied by a progressive decrease in cell size with loss in protein mass. In lymphocytes from Hiv-infected persons, protein loss during apoptosis is due to increased protein degradation rather than decreased synthesis. To identify and characterize the proteolytic enzymes or enzyme systems involved in this process, we studied several features of protein turnover in lymphocytes from peripheral blood and lymph nodes during the natural and experimental infection by feline immunodeficiency virus (Fiv). This animal model allowed us to integrate in vivo results with in vitro observations of protein damage. Here we report that protein breakdown in apoptotic cells is concomitant with the activation of the ATP and ubiquitin-dependent multicatalytic system (proteasome). We suggest that proteasome activation is part of the proteolytic cascade in the execution phases of apoptosis in AIDS.

Effects of flow triggering on breathing effort during partial ventilatory support

The effects of flow triggering (FT) as compared with pressure triggering (PT) on breathing effort have been the focus of several studies, and discrepant results have been reported. In the initial part of our study, a lung model was used to quantify triggering effort (airway pressure-time product, PTPaw) for a range of sensitivity settings in nine new-generation ventilators. A ventilator providing both FT and PT was then used to compare these systems during pressure-support (PSV) and volume-targeted assist-control ventilation (ACV) in eight ventilator-dependent patients, using sensitivity settings (2 L/min for FT and -2 cm H2O for PT) that had proven significantly different in the initial bench study. Indexes of effort included the esophageal and transdiaphragmatic pressure-time products and inspiratory work of breathing per minute (PTPes/min, PTPdi/min, and Wi/min, respectively). The experimental study revealed significant differences between ventilators in PTPaw at commonly used settings. In two of three ventilators featuring both systems, PTPaw was significantly lower with FT than PT (p < 0.001). In the clinical study, FT as compared with PT, was associated with reductions in all indexes of breathing effort during PSV: 16 +/- 6% (p < 0.001), 13 +/- 10% (p < 0.01), and 14 +/- 12% (p < 0.05) for PTPdi/min, PTPes/min, and Wi/min, respectively. By contrast, no differences were found when FT was used during ACV. Although FT reduced triggering effort in both modes (p < 0.001), the effects observed during the post-trigger phase differed, and explained the discrepant results between the two modes. We conclude that FT more effectively reduces breathing effort when used in conjunction with a pressure-targeted mode than with a volume-targeted mode, especially when flow delivery is close to or below demand.

Oxidative protein damage and degradation in lymphocytes from patients infected with human immunodeficiency virus

It has been proposed that oxidative stress is the common mediator of apoptotic cell death in AIDS. However, mechanistic relationships between oxidative damage and cell death are far from clear. It is reported here that the mitogenic activation of T lymphocytes from human immunodeficiency virus-positive subjects involves perturbation of redox balance, as indicated by the increase in hydroethydine intracellular oxidation and manganese superoxide dismutase adaptive induction. Principal molecular targets of oxidative injury are cellular proteins whose content in carbonyl groups increases together with a dramatic increase in degradation of newly synthesized proteins catalyzed by the ATP- and ubiquitin-dependent proteolytic system. The major consequence of this metabolic anomaly is the decrease in protein cell mass leading to cells that are smaller than normal at lethal mitosis.

Identification of alpha-spectrin domains susceptible to ubiquitination

Previously, we demonstrated that alpha-spectrin is a substrate for the ubiquitin system and that this conjugation is a dynamic process (Corsi, D., Galluzzi, L., Crinelli, R., and Magnani, M. (1995) J. Biol. Chem. 270, 8928-8935). In this study, we mapped the sites of ubiquitination on erythrocyte alpha-spectrin. A peptide map of digested alpha-spectrin, previously submitted to in vitro 125I-ubiquitin conjugation, revealed the presence of four distinct labeled bands with Mr 40,000, 36,000, 29,000, and 25,500. Western blotting experiments using antibodies against each alpha-spectrin domain revealed that only IgG anti-alphaIII domain recognized the 125I-labeled ubiquitin peptide of 29 kDa, whereas the IgG anti-alphaV domain recognized the Mr 40,000 125I-ubiquitin-labeled peptide. The other two labeled bands of Mr 36,000 and Mr 25,500 were identified as tetra and tri multiubiquitin chains. Ubiquitination of the alphaIII and alphaV domains was further confirmed by anti-alpha-spectrin domain immunoaffinity chromatography. Endoprotease Lys C-digested spectrin conjugated previously to 125I-ubiquitin was incubated with antibodies against each trypsin-resistant domain of alpha-spectrin. Gamma counting of the radiolabeled antigen-antibody complexes purified by protein A chromatography showed labeling in the IgG anti-alphaIII and anti-alphaV complexes alone. Domain alphaIII is not associated with any known function, whereas domain alphaV contains the nucleation site for the association of the alpha and beta chains. Ubiquitination of the latter domain suggests a role for ubiquitin in the modulation of the stability, deformability, and viscoelastic properties of the erythrocyte membrane.

High-level expression and purification of a human "mini"-hexokinase

Human hexokinase type I is a 100-kDa enzyme with the catalytic site located in the C-terminal domain. We had previously expressed this domain in Escherichia coli, however only a small amount of the recombinant enzyme was catalytically active. To overcome this problem we have now expressed the "mini"-hexokinase using the pET expression system. An average of 1000 U of enzyme per liter of culture was obtained. The recombinant enzyme was purified to homogeneity by a combination of ion-exchange chromatography, affinity chromatography, and dye-ligand chromatography. The enzyme was unstable under ultrafiltration; thus, a multicolumn purification procedure was developed in order to avoid the ultrafiltration steps. The recombinant "mini"-hexokinase was found to have the same kinetic properties as the entire enzyme. Using the method described, the enzyme can be obtained in sufficient quantities for biophysical and biochemical investigations.

Ubiquitin is conjugated to the cytoskeletal protein alpha-spectrin in mature erythrocytes

Ubiquitination of red blood cell (RBC) proteins was investigated by encapsulation of 125I-ubiquitin into human erythrocytes using a procedure of hypotonic dialysis, isotonic resealing, and reannealing. Incubation (37 degrees C, up to 2 h) of 125I-ubiquitin-loaded cells resulted in the recovery of 125I-ubiquitin with the cytosolic proteins (9.22 +/- 0.4 micrograms/ml RBC) and conjugated to membrane proteins (2.18 +/- 0.05 micrograms/ml RBC). This conjugation was time-dependent, and the predominant membrane protein band that became labeled showed an apparent molecular mass of 240 kDa on SDS-polyacrylamide gel electrophoresis (PAGE). Western blotting experiments with three different anti-ubiquitin antibodies revealed that this protein is also ubiquitinated in vivo. Cell-free experiments have shown that fraction II (a DEAE-bound protein fraction eluted by 0.5 M KCl) prepared from both mature erythrocytes and reticulocytes is able to conjugate ubiquitin to this protein. Ubiquitin conjugation was ATP-dependent (Km 0.09 mM), time-dependent, and fraction II-dependent (8 +/- 0.5 pmol of 125I-ubiquitin/h/mg of fraction II). Isolation of the major RBC membrane protein that is ubiquitinated was obtained by using biotinylated ubiquitin. Membrane proteins, once ubiquitinated with this derivative, were extracted and purified by affinity chromatography on immobilized avidin. The major components retained by the column were two peptides of molecular masses 220 and 240 kDa. Both proteins are recognized by a monoclonal anti-spectrin antibody, but only the 240-kDa component is detected by streptavidin peroxidase conjugate. That indeed the ubiquitinated membrane protein of 240-kDa is alpha-spectrin was confirmed by immunoaffinity chromatography using 125I-ubiquitin and a monoclonal anti-spectrin antibody. Antigen-antibody complexes were purified by protein A chromatography and analyzed by SDS-PAGE and autoradiography. Again two bands of 240 and 220 kDa were eluted (alpha- and beta-spectrin), but only one band corresponding to the electrophoretic mobility of alpha-spectrin was detected by autoradiography. Thus, alpha-spectrin is a substrate for the ATP-dependent ubiquitination system, suggesting that the cytoskeleton is covalently modified by ubiquitination both in reticulocytes and mature RBC.