X-linked Dilated Cardiomyopathy with Mutation in the 5′ Splice Site Intron 1 of Dystrophin Gene with Utrophin Upregulation

We report a teenage boy presented with dilated cardiomyopathy (DCM) with no initial skeletal involvement and initial normal creatine kinases. One year after the heart transplantation, he had exercise-induced transient muscle weakness with elevated creatine kinases (CKs). Muscle biopsy showed normal structures and normal dystrophin immunohistochemical labeling, but utrophin, which is an autosomal homologue of dystrophin, was overexpressed at sarcolemma. Sanger sequencing confirmed a heterozygous c.31 + 1G > A, 5′ splice site point mutation at the first intron of dystrophin gene. A review of previous reports of patients with different point mutations in the same region, the first exon–intron boundary that involved the muscle promotor to exon 1, confirmed a high correlation of cardiospecific phenotype sparing the muscles with this specific site of mutations. The confirmation of upregulation of brain and Purkinje isoforms of dystrophin protein in the skeletal muscles but not in the heart in past studies help to explain the skeletal sparing presentation. X-linked DCM (XLDCM) is an important cause of isolated cardiomyopathy. Routine immunohistochemical staining study including dystrophin in cardiac muscle biopsy, and dystrophin and utrophin labelling on skeletal muscle biopsy for patients with subsequent muscle symptoms or raised creatine kinases, help in the early diagnosis of the XLDCM. Future experimental study to determine the aberrant pre-mRNA splicing of this specific splice site mutation involving exon 1 and intron 1 will help to understand better the underlying complex mechanism of the splicing regulation.

Abstract P2-08-01: Results from a randomized placebo-controlled phase 2 trial evaluating exemestane ± enzalutamide in patients with hormone receptor–positive breast cancer

This abstract was withdrawn by the authors.

Abstract P3-07-18: Exercise and triple negative breast cancer: Unravelling the anti-neoplastic molecular factors through novel culture method

Background

Despite advances to ameliorate breast cancer survival, triple negative breast cancers (TNBCs) attribute to highly disproportionate mortalities due to its aggressiveness and poor therapeutic response (Bao et al., Cancer Medicine 2014). Despite the lack of target-specific drugs, chemotherapy is the mainstay treatment, warranting more efficacious measures against TNBCs. Studies have shown that physical activity intervention reduced breast cancer risk between 20-80% (Monnikohf et. al., Epidemiology 2007) as well as breast cancer related mortality by 34% (Ibrahim et al., Med Onc 2010). However, it is clear that such intervention uptake in the population may not be feasible given the longstanding public health drive to increase physical activity. Therefore it is imperative to identify the molecular factors that might be involved in cancer prevention and therapy with the long term goal of developing a supplement. Due to the recent epidemiological findings on exercise and breast cancer, we wanted to develop a system to comprehensively identify beneficial myokines using a cell culture system.

Methods

For this study we differentiated C2C12 myoblasts into myotubules. Myotubules were contracted in Krebs Ringer Buffer solution with the C-Pace EP Pacer for 8 hours. Buffer was collected and concentrated using Amicon Ultra-0.5 centrifugal filter tubes to produced an exercise/conditioned medium. To explore the effects of exercise on breast cancer cell lines MCF-7 (ER+) and MDA-MB468 (TNBC line) were treated with conditioned medium for 48 hrs. To explore the effects of exercise and chemotherapeutic efficacy MDA-MB468 cells were treated with doxorubicin, conditioned medium or both for 48 hrs. Protein was isolated and processed for immunoblot analysis. Cell cycle markers p21, pRb, cyclin D1, PCNA as well as apoptotic marker cPARP were assessed to reveal the effects treatment.

Results

Treatment of conditioned medium in MCF-7 revealed marked changes in both p21 (92% increase, p=0.05) and pRb protein expression (62% decrease, p<0.05) as well as a modest reduction in PCNA (24% decrease , p<0.02). Conditioned medium treatment in MDA-MB468 cells showed a reduction in cyclin D1 and PCNA expression (40%, p<0.01 and 30%, p<0.02) as well as an induction of cPARP expression (32%, p=0.09). Doxorubicin treatment increased p21 and cPARP protein expression (2.2-fold increase, p<0.01 and 80% increase, p<0.05 respectively). Treatment of conditioned medium and doxorubicin displayed a synergistic effect with a 3.65-fold increase in p21 (p<0.01) and 130% increase in cPARP (p=0.01).

Conclusions

We have developed a novel system that may enable, for the first time, mechanistic studies to elucidate the role of skeletal muscle/exercise in breast cancer prevention and chemotherapy. Our data indicates a secreted factor(s) from skeletal muscles that plays a role in anti-proliferative and pro-apoptotic effects, which are the hallmark of exercise's anti-neoplastic properties. Studies are ongoing to further understand, characterize and isolate this factor(s) for therapeutic purposes. Given the limited chemotherapeutic options and heterogeneity in TNBC, our exercise culture system sheds a promising light on novel drug development and chemo-sensitization.

Citation Format: Dela Cruz MA, Roy P, Chowdhury S, Chan S, Roy HK. Exercise and triple negative breast cancer: Unravelling the anti-neoplastic molecular factors through novel culture method [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-18.

Abstract P4-22-08: A single-arm phase 2 study to assess clinical activity, efficacy and safety of enzalutamide with trastuzumab in HER2+ AR+ metastatic or locally advanced breast cancer

Background:Androgen receptor (AR) expression has been observed in up to 77% of human epidermal growth factor receptor 2–positive (HER2+) breast cancer (BC).References:1 Enzalutamide (ENZA) is a potent AR inhibitor approved for patients (pts) with metastatic castration-resistant prostate cancer. In vitro, ENZA enhances antitumor activity of trastuzumab in HER2+ AR+ cell lines and inhibits proliferation in trastuzumab-resistant HER2+ cell lines.2

Methods:Pts with metastatic or locally advanced BC that was HER2+ AR+ by local or central laboratory assessment were enrolled in a single-arm, Simon 2-stage phase 2 study (NCT02091960). Key eligibility criteria included availability of a tissue sample, presence of measurable or evaluable disease per RECIST v1.1, progression on prior trastuzumab and ≥1 prior line of anti-HER2 therapy as the most recent regimen. Brain metastases and history of seizure were exclusionary. Evaluable pts were those with centrally confirmed nuclear AR expression≥10% by immunohistochemistry who received ≥1 dose of ENZA and had ≥1 postbaseline tumor assessment. Pts received ENZA 160 mg daily and trastuzumab 6 mg/kg every 21 days until disease progression. The primary objective was clinical benefit rate at 24 weeks (CBR24), defined as complete or partial response (CR or PR) or stable disease (SD) for ≥24 weeks in evaluable pts. Additional endpoints included safety and progression-free survival (PFS). CBR24 in ≥3 of 21 evaluable pts was required to continue to stage 2 and enrollment of up to 66 evaluable pts total. This design yields a 1-sided type 1 error of 5% and 90% power when the true response is 25%.

Results:Here we present results from stage 1 (data cutoff: Mar 23, 2016), with 22 evaluable pts enrolled (pts 21 and 22 enrolled simultaneously); 18 had received ≥4 prior lines of therapy. Median duration of ENZA exposure was 144 days (range, 22-495), mean number of complete trastuzumab infusions was 6.5. CBR24 was 27.3% (95% confidence interval [CI], 10.7-50.2); 2 confirmed PR and 4 SD ≥24 weeks. Median PFS was 108 days (95% CI, 56-144). All pts experienced ≥1 adverse event (AE) any grade; 5 pts experienced AEs grade ≥3. ENZA-related AEs were reported in 16 pts (72.7%), the most common (in ≥10% of pts) were fatigue (22.7%), nausea (18.2%), diarrhea (13.6%) and arthralgia (13.6%). Serious AEs were reported in 6 pts (27.3%; 2 each of infection and back pain, 1 each of abdominal pain, nausea, vomiting, pyrexia, urinary retention and pulmonary edema). Two pts discontinued due to drug-related AEs: 1 related to both drugs, 1 related to trastuzumab. One on-study death from pulmonary edema was reported, which was not considered related to either drug.

Conclusion:Stage 1 met its primary objective. No new safety signals were identified, and the safety profile in this study was similar to that in men with prostate cancer and women with other BC subtypes treated with ENZA. These results are encouraging for a heavily pretreated population with advanced HER2+ AR+ BC. Enrollment in stage 2 continues with the combination of ENZA and trastuzumab.

1. Micello D et al. Virchows Arch. 2010;457:467-476.

2. Richer J. Presented at AACR Advances in Breast Cancer, San Diego, CA, 2013.

Citation Format: Krop I, Cortes J, Miller K, Huizing MT, Provencher L, Gianni L, Chan S, Trudeau M, Steinberg J, Sugg J, Liosatos M, Paton VE, Peterson A, Wardley A. A single-arm phase 2 study to assess clinical activity, efficacy and safety of enzalutamide with trastuzumab in HER2+ AR+ metastatic or locally advanced breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-08.

Quantitative Evaluation of Medial Temporal Lobe Morphology in Children with Febrile Status Epilepticus: Results of the FEBSTAT Study

BACKGROUND AND PURPOSE

The pathogenesis of febrile status epilepticus is poorly understood, but prior studies have suggested an association with temporal lobe abnormalities, including hippocampal malrotation. We used a quantitative morphometric method to assess the association between temporal lobe morphology and febrile status epilepticus.

MATERIALS AND METHODS

Brain MR imaging was performed in children presenting with febrile status epilepticus and control subjects as part of the Consequences of Prolonged Febrile Seizures in Childhood study. Medial temporal lobe morphologic parameters were measured manually, including the distance of the hippocampus from the midline, hippocampal height:width ratio, hippocampal angle, collateral sulcus angle, and width of the temporal horn.

RESULTS

Temporal lobe morphologic parameters were correlated with the presence of visual hippocampal malrotation; the strongest association was with left temporal horn width (P < .001; adjusted OR, 10.59). Multiple morphologic parameters correlated with febrile status epilepticus, encompassing both the right and left sides. This association was statistically strongest in the right temporal lobe, whereas hippocampal malrotation was almost exclusively left-sided in this cohort. The association between temporal lobe measurements and febrile status epilepticus persisted when the analysis was restricted to cases with visually normal imaging findings without hippocampal malrotation or other visually apparent abnormalities.

CONCLUSIONS

Several component morphologic features of hippocampal malrotation are independently associated with febrile status epilepticus, even when complete hippocampal malrotation is absent. Unexpectedly, this association predominantly involves the right temporal lobe. These findings suggest that a spectrum of bilateral temporal lobe anomalies are associated with febrile status epilepticus in children. Hippocampal malrotation may represent a visually apparent subset of this spectrum.

Liposomal Doxorubicin in Breast Cancer

Drug-delivery carriers represent an important step in the development of targeted therapy. Encapsulation of drug into liposomes represents such a carrier, and helps to minimize side effects of conventional doxorubicin by improving the tumor-specific biodistribution profile. We review the development of the two liposomal doxorubicin formulations, pegylated liposomal doxorubicin and liposomal-encapsulated doxorubicin citrate from reconstitution and comparative pharmacokinetics to pivotal Phase III trials, with special emphasis in breast cancer. The relative differences in the toxicity profile can be attributed to their differences in the liposomal formulations. Areas of special interest include the reduction in cardiac toxicities and the improved efficacy, such as in the treatment of ovarian cancer. These improvements have also increased the potential of these liposomal formulations of doxorubicin for combination and sequencing with other biological and cytotoxic agents for clinical benefit.