NOTCH3 expression is linked to breast cancer seeding and distant metastasis.

BACKGROUND: Development of distant metastases involves a complex multistep biological process termed the invasion-metastasis cascade, which includes dissemination of cancer cells from the primary tumor to secondary organs. NOTCH developmental signaling plays a critical role in promoting epithelial-to-mesenchymal transition, tumor stemness, and metastasis. Although all four NOTCH receptors show oncogenic properties, the unique role of each of these receptors in the sequential stepwise events that typify the invasion-metastasis cascade remains elusive. METHODS: We have established metastatic xenografts expressing high endogenous levels of NOTCH3 using estrogen receptor alpha-positive (ERα+) MCF-7 breast cancer cells with constitutive active Raf-1/mitogen-associated protein kinase (MAPK) signaling (vMCF-7Raf-1) and MDA-MB-231 triple-negative breast cancer (TNBC) cells. The critical role of NOTCH3 in inducing an invasive phenotype and poor outcome was corroborated in unique TNBC cells resulting from a patient-derived brain metastasis (TNBC-M25) and in publicly available claudin-low breast tumor specimens collected from participants in the Molecular Taxonomy of Breast Cancer International Consortium database. RESULTS: In this study, we identified an association between NOTCH3 expression and development of metastases in ERα+ and TNBC models. ERα+ breast tumor xenografts with a constitutive active Raf-1/MAPK signaling developed spontaneous lung metastases through the clonal expansion of cancer cells expressing a NOTCH3 reprogramming network. Abrogation of NOTCH3 expression significantly reduced the self-renewal and invasive capacity of ex vivo breast cancer cells, restoring a luminal CD44low/CD24high/ERαhigh phenotype. Forced expression of the mitotic Aurora kinase A (AURKA), which promotes breast cancer metastases, failed to restore the invasive capacity of NOTCH3-null cells, demonstrating that NOTCH3 expression is required for an invasive phenotype. Likewise, pharmacologic inhibition of NOTCH signaling also impaired TNBC cell seeding and metastatic growth. Significantly, the role of aberrant NOTCH3 expression in promoting tumor self-renewal, invasiveness, and poor outcome was corroborated in unique TNBC cells from a patient-derived brain metastasis and in publicly available claudin-low breast tumor specimens. CONCLUSIONS: These findings demonstrate the key role of NOTCH3 oncogenic signaling in the genesis of breast cancer metastasis and provide a compelling preclinical rationale for the design of novel therapeutic strategies that will selectively target NOTCH3 to halt metastatic seeding and to improve the clinical outcomes of patients with breast cancer.

Safety and Efficacy of the Combination Lurbinectedin plus Doxorubicin from a Phase 1b Trial in Patients with Advanced/Metastatic Soft-Tissue Sarcoma.

PURPOSE: While cytotoxic chemotherapy is the standard first-line treatment for patients with metastatic soft-tissue sarcoma (STS), clinical outcomes remain suboptimal. Our prior study showed lurbinectedin plus doxorubicin is well tolerated with promising clinical activity in STS. We designed this phase 1b trial to optimize dosing as the basis for a randomized trial in leiomyosarcoma and to further explore the safety profile and efficacy signal. PATIENTS AND METHODS: Patients had advanced/metastatic STS and no prior anthracycline/lurbinectedin/trabectedin. Escalation followed a 3 + 3 design with 3-week cycles: lurbinectedin (3.2 mg/m2 day 1) and two doxorubicin levels (DL1, 25 mg/m2 day 1; DL2, 25 mg/m2 days 1 and 8). The primary objectives were to identify the maximum tolerated dose and recommended dose for subsequent randomized trials. RESULTS: Ten patients were enrolled in a 6-month period. The most common treatment-emergent adverse events were grade (G) 2 fatigue and nausea, and G2 cytopenias with no febrile neutropenia events. There were two dose-limiting toxicities (DLTs) at DL2 [day 8 (G2 alanine aminotransferase [ALT]/aspartate aminotransferase increase, G3 neutropenia)], and one DLT in DL1 (G3 ALT increase). These were reversible and all patients continued the study. DL1 was chosen for further study. At the time of data cutoff, the estimated median progression-free survival is 16.5 months [95% confidence interval (CI), 6.0-ND]. The objective response rate was 60% (6/10 confirmed partial responses). CONCLUSIONS: In this phase 1b study, the recommended dose is lurbinectedin 3.2 mg/m2 in combination with doxorubicin 25 mg/m2 every 3 weeks. The study combination was well tolerated and demonstrated intriguing clinical activity.

Diagnosis and management of dedifferentiated liposarcoma: A multidisciplinary position statement.

Dedifferentiated liposarcoma (DDLPS) is a malignant mesenchymal neoplasm in desperate need of novel therapeutic approaches. Often occurring in conjunction with well-differentiated liposarcoma (WDLPS), DDLPS can behave more aggressively and exhibits a significant risk for developing recurrence or metastatic disease when compared to its well-differentiated counterpart. A multidisciplinary approach is critically important, particularly for patients with localized disease, as disease presentations are often complex, and the management of patients has become increasingly nuanced as treatment approaches have become more refined. Expert pathology review and appropriate application of diagnostic molecular techniques are key components of DDLPS diagnosis and also reflect an improved understanding of the underlying pathogenesis of the disease. Systemic therapies remain limited for DDLPS, but novel therapies targeting important underlying molecular drivers have resulted in ongoing clinical trials aiming to improve outcomes for patients with advanced disease. In recognition of the increased activity and interest within the DDLPS field, a multidisciplinary group of nationally recognized experts in medical oncology, surgical oncology, radiation oncology, and pathology was convened to summarize key insights. This position paper highlights important points from the meeting and provides evidence-based recommendations for practicing clinicians.

Phase II Study of Eribulin plus Pembrolizumab in Metastatic Soft-tissue Sarcomas: Clinical Outcomes and Biological Correlates.

PURPOSE: Eribulin modulates the tumor-immune microenvironment via cGAS-STING signaling in preclinical models. This non-randomized phase II trial evaluated the combination of eribulin and pembrolizumab in patients with soft-tissue sarcomas (STS). PATIENTS AND METHODS: Patients enrolled in one of three cohorts: leiomyosarcoma (LMS), liposarcomas (LPS), or other STS that may benefit from PD-1 inhibitors, including undifferentiated pleomorphic sarcoma (UPS). Eribulin was administered at 1.4 mg/m2 i.v. (days 1 and 8) with fixed-dose pembrolizumab 200 mg i.v. (day 1) of each 21-day cycle, until progression, unacceptable toxicity, or completion of 2 years of treatment. The primary endpoint was the 12-week progression-free survival rate (PFS-12) in each cohort. Secondary endpoints included the objective response rate, median PFS, safety profile, and overall survival (OS). Pretreatment and on-treatment blood specimens were evaluated in patients who achieved durable disease control (DDC) or progression within 12 weeks [early progression (EP)]. Multiplexed immunofluorescence was performed on archival LPS samples from patients with DDC or EP. RESULTS: Fifty-seven patients enrolled (LMS, n = 19; LPS, n = 20; UPS/Other, n = 18). The PFS-12 was 36.8% (90% confidence interval: 22.5-60.4) for LMS, 69.6% (54.5-89.0) for LPS, and 52.6% (36.8-75.3) for UPS/Other cohorts. All 3 patients in the UPS/Other cohort with angiosarcoma achieved RECIST responses. Toxicity was manageable. Higher IFNα and IL4 serum levels were associated with clinical benefit. Immune aggregates expressing PD-1 and PD-L1 were observed in a patient that completed 2 years of treatment. CONCLUSIONS: The combination of eribulin and pembrolizumab demonstrated promising activity in LPS and angiosarcoma.

Emerging predictive biomarkers in the management of bone and soft tissue sarcomas.

INTRODUCTION: Soft tissue and bone sarcomas are a heterogeneous group of malignancies, each with a unique biology and clinical course. As our understanding of individual sarcoma subtypes and their molecular landscapes increases, predictive biomarkers are emerging to improve patient selection for chemotherapies, targeted therapies, and immunotherapy approaches. AREAS COVERED: This review highlights predictive biomarkers rooted in molecular mechanisms of sarcoma biology, focusing on cell cycle regulation, DNA damage repair, and immune microenvironment interactions. We review CDK4/6 inhibitor predictive biomarkers, including CDKN2A loss, ATRX status, MDM2 levels, and Rb1 status. We discuss homologous recombination deficiency (HRD) biomarkers that predict vulnerability to DNA damage repair (DDR) pathway inhibitors, such as molecular signatures and functional HRD markers. We describe tertiary lymphoid structures and suppressive myeloid cells in the sarcoma immune microenvironment that may influence immunotherapy efficacy. EXPERT OPINION: While predictive biomarkers are not routinely used in sarcoma clinical practice currently, emerging biomarkers are being developed alongside clinical advancements. Novel therapies and predictive biomarkers will be essential for individualizing future approaches to sarcoma management and improving patient outcomes.

MRTX1719 Is an MTA-Cooperative PRMT5 Inhibitor That Exhibits Synthetic Lethality in Preclinical Models and Patients with MTAP-Deleted Cancer.

Previous studies implicated protein arginine methyltransferase 5 (PRMT5) as a synthetic lethal target for MTAP-deleted (MTAP del) cancers; however, the pharmacologic characterization of small-molecule inhibitors that recapitulate the synthetic lethal phenotype has not been described. MRTX1719 selectively inhibited PRMT5 in the presence of MTA, which is elevated in MTAP del cancers, and inhibited PRMT5-dependent activity and cell viability with >70-fold selecti-vity in HCT116 MTAP del compared with HCT116 MTAP wild-type (WT) cells. MRTX1719 demonstrated dose-dependent antitumor activity and inhibition of PRMT5-dependent SDMA modification in MTAP del tumors. In contrast, MRTX1719 demonstrated minimal effects on SDMA and viability in MTAP WT tumor xenografts or hematopoietic cells. MRTX1719 demonstrated marked antitumor activity across a panel of xenograft models at well-tolerated doses. Early signs of clinical activity were observed including objective responses in patients with MTAP del melanoma, gallbladder adenocarcinoma, mesothelioma, non-small cell lung cancer, and malignant peripheral nerve sheath tumors from the phase I/II study. SIGNIFICANCE: PRMT5 was identified as a synthetic lethal target for MTAP del cancers; however, previous PRMT5 inhibitors do not selectively target this genotype. The differentiated binding mode of MRTX1719 leverages the elevated MTA in MTAP del cancers and represents a promising therapy for the ∼10% of patients with cancer with this biomarker. See related commentary by Mulvaney, p. 2310. This article is featured in Selected Articles from This Issue, p. 2293.

Recent advances in the understanding and management of liposarcoma.

Liposarcomas are a common subfamily of soft tissue sarcoma with several subtypes recognized by the World Health Organization: atypical lipomatous tumors (ALT)/well-differentiated liposarcoma (WDLPS), dedifferentiated liposarcoma (DDLPS), myxoid liposarcoma (MLPS), pleomorphic liposarcoma (PLPS), and myxoid pleomorphic liposarcoma (MPLPS). Despite shared adipocytic features among liposarcomas, the clinical approach to each subtype differs based on histology, location, clinical behavior, and specific oncogenic drivers. In this review, we highlight subtype-specific molecular features with the potential to generate novel therapies. We discuss recent clinical trials investigating the use of preoperative radiation therapy for retroperitoneal liposarcoma, chemotherapy, small molecule inhibitors, and innovative immunotherapy approaches and describe how we incorporate these advancements into the management of liposarcoma.

Immune checkpoint inhibitors: an emerging cause of insulin-dependent diabetes.

Objective: Insulin-dependent diabetes can occur with immune checkpoint inhibitor (ICI) therapy. We aimed to characterize the frequency, natural history and potential predictors of ICI-induced diabetes. Research design and methods: We reviewed 1444 patients treated with ICIs over 6 years at our cancer center, and from the 1163 patients who received programmed cell death protein 1 (PD-1) inhibitors, we identified 21 such cases, 12 of which developed new-onset insulin-dependent diabetes and 9 experienced worsening of pre-existing type 2 diabetes. Results: ICI-induced diabetes occurred most frequently with pembrolizumab (2.2%) compared with nivolumab (1%) and ipilimumab (0%). The median age was 61 years, and body mass index was 31 kg/m2, which are both higher than expected for spontaneous type 1 diabetes. Other immune-related adverse events occurred in 62%, the most common being immune mediated thyroid disease. New-onset insulin-dependent diabetes developed after a median of four cycles or 5 months; 67% presented with diabetic ketoacidosis and 83% with low or undetectable C-peptide. Autoantibodies were elevated in 5/7 (71%) at the time of new-onset diabetes. Diabetes did not resolve during a median follow-up of 1 year. Conclusions: PD-1 inhibitors can lead to insulin deficiency presenting as new-onset diabetes or worsening of pre-existing type 2 diabetes, with a frequency of 1.8 %. The underlying mechanism appears similar to spontaneous type 1 diabetes but there is a faster progression to severe insulin deficiency. Better characterization of ICI-induced diabetes will improve patient care and enhance our understanding of immune-mediated diabetes.

Using social media to disseminate education about Alzheimer's prevention & treatment: a pilot study on Alzheimer's universe (www.AlzU.org).

BACKGROUND: The use of social media may be a valuable tool for dissemination of patient education interventions. However, in Alzheimer's disease (AD), little data exists about the effectiveness, associated cost, or conditions for utilization. METHODS: Alzheimer's Universe (www.AlzU.org) is an online educational portal that provides evidence-based educational content for the public and a variety of activities related to optimizing AD management. The primary goal of our study was to assess the effectiveness of using the social media platform Facebook.com as a tool to recruit subjects to visit AlzU.org via targeted advertising and evaluate the associated costs. Secondary outcomes included AlzU.org join rates, lesson and activity completion rates, user demographics and attitudes about the education research platform. RESULTS: A total of $706 generated 4268 visits to AlzU.org via a series of page posts promoted with targeted advertising to individuals with previously expressed interest in 'Alzheimer's disease,' to those who had 'liked' the Alzheimer's Association page, and followers of www.facebook.com/AlzheimersDisease. Advertising used different promotional taglines in the Facebook Advertising manager tool using 'Cost Per Click' and the 'Optimized for Engagement' settings. Across all strategies combined, 503 visitors joined AlzU.org (11.8% join rate), 412 engaged with at least one lesson/activity (82%), and 100 completed all available lessons and activities (19.8%). Users were primarily women (79.8%) and the most common age group was 50's (43.3%, range 22-92). The majority joined AlzU.org to learn more about AD prevention or treatment (66.3% and 65.3%, respectively). Over 90% were satisfied with their experience. DISCUSSION: Subjects were quickly and cost-effectively recruited to AlzU.org. Completion rates of education content and activities were adequate, and subjects were highly satisfied with their experiences. Overall, targeted advertising on Facebook.com was an effective means of disseminating AD education online.

Extraskeletal Osteosarcoma: Outcomes and the Role of Chemotherapy.

OBJECTIVES: Extraskeletal osteosarcoma (EO) is a malignant neoplasm that produces osteoid, bone, and chondroid material without direct attachment to bone or periosteum. Surgical resection is the mainstay of treatment; the role of chemotherapy is not well defined. Therefore, we evaluated the impact of chemotherapy in the survival of patients with EO. METHODS: All EO patients seen at Mayo Clinic between 1990 and 2014 were assessed. Forty-three patients were included after all archived pathology slides were reviewed to confirm the diagnosis of EO. RESULTS: Of 43 patients, 37 patients had localized disease and 6 patients had metastatic disease at diagnosis. Chemotherapy was used in 73% and 75% of patients, respectively. Chemotherapy was predominantly anthracycline based, and included platinum in 22 patients (84%).Median overall survival (OS) and progression-free survival (PFS) were 50 months (95% confidence interval, 25-99), and 21 months (95% confidence interval, 13-not reached), respectively. There was a trend towards longer OS and PFS in patients who received chemotherapy. Those who received platinum-based therapy had remarkably prolonged OS (median, 182 vs. 18 mo; 5-year, 61% vs. 0%; P=0.01) and PFS (median, not reached vs. 10 mo; 5-year, 56% vs. 0%; P=0.005). Baseline characteristics were similar in the platinum and nonplatinum group.In patients who received chemotherapy, relapse/recurrence rate was lower in the platinum-based group (41%) as opposed to the nonplatinum-based group (100%; P=0.02). In the neoadjuvant setting, the overall response rate of platinum-containing regimens was 27%. CONCLUSIONS: Our results suggest a clinical benefit when platinum-based chemotherapy is incorporated in the management of patients with EO. We plan to validate this further with an expanded multicenter analysis.

Representation of Minorities and Women in Oncology Clinical Trials: Review of the Past 14 Years.

PURPOSE: Many cancer clinical trials lack appropriate representation of specific patient populations, limiting their generalizability. Therefore, we determined the representation of ethnic minorities and women in cancer clinical trials. METHODS: Enrollment data from all therapeutic trials reported as completed in ClinicalTrials.gov from 2003 to 2016 were analyzed. We calculated enrollment fractions (EFs) for each group, defined as the number of enrollees divided by the 2013 Surveillance, Epidemiology, and End Results (SEER) database cancer prevalence. RESULTS: Of 1,012 clinical trials, 310 (31%) reported ethnicity with a total of 55,689 enrollees. Participation varied significantly across ethnic groups. Non-Hispanic whites were more likely to be enrolled in clinical trials (EF, 1.2%) than African Americans (EF, 0.7%; P < .001) and Hispanics (EF, 0.4%; P < .001). A decrease in African American (6% v 9.2%) and Hispanic (2.6% v 3.1%) enrollment was observed when compared with historical data from 1996 to 2002. Younger patients (age younger than 65 years) were more likely to be enrolled in clinical trials than the elderly (64% v 36%; P < .001). Low recruitment of female patients was observed in clinical trials for melanoma (35%), lung cancer (39%), and pancreatic cancer (40%). CONCLUSION: We observed a decrease in recruitment of minorities over the past 14 years compared with historical data. African Americans, Hispanics, and women were less likely to be enrolled in cancer clinical trials. Future trials should take extra measures to recruit participants that adequately represent the US cancer population.

Aurora-A overexpression is linked to development of aggressive teratomas derived from human iPS cells.

The discovery of human induced pluripotent stem cells (hiPSCs) is a promising advancement in the field of regenerative and personalized medicine. Expression of SOX2, KLF4, OCT4 and MYC transcription factors induces the nuclear reprogramming of somatic cells into hiPSCs that share striking similarities with human embryonic stem cells (hESCs). However, several studies have demonstrated that hESCs and hiPSCs could lead to teratoma formation in vivo, thus limiting their current clinical applications. Aberrant cell cycle regulation of hESCs is linked to centrosome amplification, which may account, for their enhanced chromosomal instability (CIN), and thus increase their tumorigenicity. Significantly, the tumor suppressor p53 plays a key role as a 'guardian of reprogramming', safeguarding genomic integrity during hiPSC reprogramming. Nevertheless, the molecular mechanisms leading to development of CIN during reprogramming and increased tumorigenic potential of hiPSCs remains to be fully elucidated. In the present study, we analyzed CIN in hiPSCs derived from keratinocytes and established that chromosomal and mitotic aberrations were linked to centrosome amplification, Aurora-A overexpression, abrogation of p53-mediated G1/S cell cycle checkpoint and loss of Rb tumor-suppressor function. When hiPSCs were transplanted into the kidney capsules of immunocompromised mice, they developed high-grade teratomas characterized by the presence of cells that exhibited non-uniform shapes and sizes, high nuclear pleomorphism and centrosome amplification. Significantly, ex vivo cells derived from teratomas exhibited high self-renewal capacity that was linked to Aurora-A kinase activity and gave rise to lung metastasis when injected into the tail vein of immunocompromised mice. Collectively, these findings demonstrated a high risk for malignancy of hiPSCs that exhibit Aurora-A overexpression, loss of Rb function, centrosome amplification and CIN. Based on these findings, we proposed that Aurora-A-targeted therapy could represent a promising prophylactic therapeutic strategy to decrease the likelihood of CIN and development of aggressive teratomas derived from hiPSCs.

Submandibular parasympathetic gangliogenesis requires sprouty-dependent Wnt signals from epithelial progenitors.

Parasympathetic innervation is critical for submandibular gland (SMG) development and regeneration. Parasympathetic ganglia (PSG) are derived from Schwann cell precursors that migrate along nerves, differentiate into neurons, and coalesce within their target tissue to form ganglia. However, signals that initiate gangliogenesis after the precursors differentiate into neurons are unknown. We found that deleting negative regulators of FGF signaling, Sprouty1 and Sprouty2 (Spry1/2DKO), resulted in a striking loss of gangliogenesis, innervation, and keratin 5-positive (K5+) epithelial progenitors in the SMG. Here we identify Wnts produced by K5+ progenitors in the SMG as key mediators of gangliogenesis. Wnt signaling increases survival and proliferation of PSG neurons, and inhibiting Wnt signaling disrupts gangliogenesis and organ innervation. Activating Wnt signaling and reducing FGF gene dosage rescues gangliogenesis and innervation in both the Spry1/2DKO SMG and pancreas. Thus, K5+ progenitors produce Wnt signals to establish the PSG-epithelial communication required for organ innervation and progenitor cell maintenance.

Osteosarcoma in pediatric patients and young adults: a single institution retrospective review of presentation, therapy, and outcome.

Background. Little is known about how cumulative chemotherapy delivery influences the poorer outcome observed in young adult (YA, 18-40 years) versus pediatric (<18 years) osteosarcoma patients. Here, we retrospectively examined differences in presentation, therapy, including cumulative chemotherapy dose, and outcome in YA and pediatric patients. Methods. We reviewed 111 cases of high-grade osteosarcoma at Moffitt Cancer Center between 1988 and 2012. Presentation factors, therapies, and survival were compared between YA and pediatric cohorts. Results. The cohorts were equivalent with respect to metastatic status, gender, tumor size, tumor site, and histological subtype. We found that the YA patients tended to have poorer histologic response to neoadjuvant chemotherapy measured by necrosis with 55% and 35% of pediatric versus YA patients responding favorably (P = 0.06). Only 39% of YA patients achieved the typical pediatric dose of methotrexate, doxorubicin, and cisplatin. These patients had a 3-year EFS of 76% (CI 53-100%) versus 47% (CI 26-69%; P = 0.09) in those who received less chemotherapy. Conclusion. Age continues to be a prognostic factor in osteosarcoma. Our study suggests that presentation factors are not associated with prognosis, while poorer response to chemotherapy and lower cumulative dose of chemotherapy delivered to YA patients may contribute to poorer outcomes.