Efficacy and Molecular Mechanisms of Differentiated Response to the Aurora and Angiogenic Kinase Inhibitor ENMD-2076 in Preclinical Models of p53-Mutated Triple-Negative Breast Cancer

A Phase Ib Expansion Cohort Evaluating Aurora A Kinase Inhibitor Alisertib and Dual TORC1/2 Inhibitor Sapanisertib in Patients with Advanced Solid Tumors

BACKGROUND

This study further evaluated the safety and efficacy of the combination of alisertib and sapanisertib in an expansion cohort of patients, including a subset of patients with refractory pancreatic adenocarcinoma, with further evaluation of the pharmacodynamic characteristics of combination therapy.

METHODS

Twenty patients with refractory solid tumors and 11 patients with pancreatic adenocarcinoma were treated at the recommended phase 2 dose of alisertib and sapanisertib. Adverse events and disease response were assessed. Patients in the expansion cohort were treated with a 7-day lead-in of either alisertib or sapanisertib prior to combination therapy, with tumor tissue biopsy and serial functional imaging performed for correlative analysis.

RESULTS

Toxicity across treatment groups was overall similar to prior studies. One partial response to treatment was observed in a patient with ER positive breast cancer, and a patient with pancreatic cancer experienced prolonged stable disease. In an additional cohort of pancreatic cancer patients, treatment response was modest. Correlative analysis revealed variability in markers of apoptosis and immune cell infiltrate according to lead-in therapy and response.

CONCLUSIONS

Dual targeting of Aurora A kinase and mTOR resulted in marginal clinical benefit in a population of patients with refractory solid tumors, including pancreatic adenocarcinoma, though individual patients experienced significant response to therapy. Correlatives indicate apoptotic response and tumor immune cell infiltrate may affect clinical outcomes.

Targeting Senescence as a Therapeutic Opportunity for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is associated with an elevated risk of recurrence and poor prognosis. Historically, only chemotherapy was available as systemic treatment, but immunotherapy and targeted therapies currently offer prolonged benefits. TNBC is a group of diseases with heterogeneous treatment sensitivity, and resistance is inevitable and early for a large proportion of the intrinsic subtypes. Although senescence induction by anticancer therapy offers an immediate favorable clinical outcome once the rate of tumor progression reduces, these cells are commonly dysfunctional and metabolically active, culminating in treatment-resistant repopulation associated with worse prognosis. This heterogeneous response can also occur without therapeutic pressure in response to damage or oncogenic stress, playing a relevant role in the carcinogenesis. Remarkably, there is preclinical and exploratory clinical evidence to support a relevant role of senescence in treatment resistance. Therefore, targeting senescent cells has been a scientific effort in many malignant tumors using a variety of targets and strategies, including increasing proapoptotic and decreasing antiapoptotic stimuli. Despite promising results, there are some challenges to applying this technology, including the best schedule of combination, assessment of senescence, specific vulnerabilities, and the best clinical scenarios. This review provides an overview of senescence in TNBC with a focus on future-proofing senotherapy strategies.

ATM kinase inhibitor AZD0156 in combination with irinotecan and 5-fluorouracil in preclinical models of colorectal cancer

Background

AZD0156 is an oral inhibitor of ATM, a serine threonine kinase that plays a key role in DNA damage response (DDR) associated with double-strand breaks. Topoisomerase-I inhibitor irinotecan is used clinically to treat colorectal cancer (CRC), often in combination with 5-fluorouracil (5FU). AZD0156 in combination with irinotecan and 5FU was evaluated in preclinical models of CRC to determine whether low doses of AZD0156 enhance the cytotoxicity of irinotecan in chemotherapy regimens used in the clinic.

Methods

Anti-proliferative effects of single-agent AZD0156, the active metabolite of irinotecan (SN38), and combination therapy were evaluated in 12 CRC cell lines. Additional assessment with clonogenic assay, cell cycle analysis, and immunoblotting were performed in 4 selected cell lines. Four colorectal cancer patient derived xenograft (PDX) models were treated with AZD0156, irinotecan, or 5FU alone and in combination for assessment of tumor growth inhibition (TGI). Immunofluorescence was performed on tumor tissues. The DDR mutation profile was compared across in vitro and in vivo models.

Results

Enhanced effects on cellular proliferation and regrowth were observed with the combination of AZD0156 and SN38 in select models. In cell cycle analysis of these models, increased G2/M arrest was observed with combination treatment over either single agent. Immunoblotting results suggest an increase in DDR associated with irinotecan therapy, with a reduced effect noted when combined with AZD0156, which is more pronounced in some models. Increased TGI was observed with the combination of AZD0156 and irinotecan as compared to single-agent therapy in some PDX models. The DDR mutation profile was variable across models.

Conclusions

AZD0156 and irinotecan provide a rational and active combination in preclinical colorectal cancer models. Variability across in vivo and in vitro results may be related to the variable DDR mutation profiles of the models evaluated. Further understanding of the implications of individual DDR mutation profiles may help better identify patients more likely to benefit from treatment with the combination of AZD0156 and irinotecan in the clinical setting.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.

Vascular Endothelial Growth Factor Receptors [VEGFR] as Target in Breast Cancer Treatment: Current Status in Preclinical and Clinical Studies and Future Directions

Breast cancer [BC] is one of the most common cancers among women, one of the leading causes of a considerable number of cancer-related death globally. Among all procedures leading to the formation of breast tumors, angiogenesis has an important role in cancer progression and outcomes. Therefore, various anti-angiogenic strategies have developed so far to enhance treatment's efficacy in different types of BC. Vascular endothelial growth factors [VEGFs] and their receptors are regarded as the most well-known regulators of neovascularization. VEGF binding to vascular endothelial growth factor receptors [VEGFRs] provides cell proliferation and vascular tissue formation by the subsequent tyrosine kinase pathway. VEGF/VEGFR axis displays an attractive target for anti-angiogenesis and anti-cancer drug design. This review aims to describe the existing literature regarding VEGFR inhibitors, focusing on BC treatment reported in the last two decades.

Oxethazaine inhibits esophageal squamous cell carcinoma proliferation and metastasis by targeting aurora kinase A

Esophageal squamous cell carcinoma (ESCC), a malignant neoplasm with high incidence, is a severe global public health threat. The current modalities used for treating ESCC include surgery, chemotherapy, and radiotherapy. Although ESCC management and treatment strategies have improved over the last decade, the overall 5-year survival rate remains <20%. Therefore, the identification of novel therapeutic strategies that can increase ESCC patient survival rates is urgently needed. Oxethazaine, an amino-amide anesthetic agent, is mainly prescribed in combination with antacids to relieve esophagitis, dyspepsia, and other gastric disorders. In the present study, we found that oxethazaine inhibited the proliferation and migration of esophageal cancer cells. According to the results of in vitro screening and binding assays, oxethazaine binds directly to AURKA, suppresses AURKA activity, and inhibits the downstream effectors of AURKA. Notably, we found that oxethazaine suppressed tumor growth in three patient-derived esophageal xenograft mouse models and tumor metastasis in vivo. Our findings suggest that oxethazaine can inhibit ESCC proliferation and metastasis in vitro and in vivo by targeting AURKA.

Aurora kinase inhibitors: a patent review (2014-2020)

Introduction: Aurora kinases are a family of serine/threonine kinases, and promote mitotic spindle assembly by regulating centrosome duplication and separation. Aurora kinases are overexpressed in a variety of tumor cell lines, thus, the use of Aurora kinase small-molecule inhibitors has become a potential treatment option for cancer.Areas covered: As a continuing review of Aurora kinase inhibitors and their patents published in 2009, 2011 and 2014. Herein, we updated the information for Aurora kinase inhibitors in clinical trials and the patents filed from 2014 to 2020. PubMed, Scopus, SciFinder, and www.clinicaltrials.gov databases were used for searching the clinical information and patents of Aurora kinase inhibitors.Expert opinion: Even though Aurora A or B selective as well as pan inhibitors show preclinical and clinical efficacy, so far, no Aurora kinase inhibitor has been approved for clinical use. Preliminary evidence suggested that highly selective Aurora kinase or multi-target inhibitors as a single agent as well as in combination therapy are still the current main development trend of Aurora kinase inhibitors.

Current methods in translational cancer research

Recent developments in pre-clinical screening tools, that more reliably predict the clinical effects and adverse events of candidate therapeutic agents, has ushered in a new era of drug development and screening. However, given the rapid pace with which these models have emerged, the individual merits of these translational research tools warrant careful evaluation in order to furnish clinical researchers with appropriate information to conduct pre-clinical screening in an accelerated and rational manner. This review assesses the predictive utility of both well-established and emerging pre-clinical methods in terms of their suitability as a screening platform for treatment response, ability to represent pharmacodynamic and pharmacokinetic drug properties, and lastly debates the translational limitations and benefits of these models. To this end, we will describe the current literature on cell culture, organoids, in vivo mouse models, and in silico computational approaches. Particular focus will be devoted to discussing gaps and unmet needs in the literature as well as current advancements and innovations achieved in the field, such as co-clinical trials and future avenues for refinement.

Targeting AURKA in Cancer: molecular mechanisms and opportunities for Cancer therapy

Aurora kinase A (AURKA) belongs to the family of serine/threonine kinases, whose activation is necessary for cell division processes via regulation of mitosis. AURKA shows significantly higher expression in cancer tissues than in normal control tissues for multiple tumor types according to the TCGA database. Activation of AURKA has been demonstrated to play an important role in a wide range of cancers, and numerous AURKA substrates have been identified. AURKA-mediated phosphorylation can regulate the functions of AURKA substrates, some of which are mitosis regulators, tumor suppressors or oncogenes. In addition, enrichment of AURKA-interacting proteins with KEGG pathway and GO analysis have demonstrated that these proteins are involved in classic oncogenic pathways. All of this evidence favors the idea of AURKA as a target for cancer therapy, and some small molecules targeting AURKA have been discovered. These AURKA inhibitors (AKIs) have been tested in preclinical studies, and some of them have been subjected to clinical trials as monotherapies or in combination with classic chemotherapy or other targeted therapies.

Preclinical and Dose-Finding Phase I Trial Results of Combined Treatment with a TORC1/2 Inhibitor (TAK-228) and Aurora A Kinase Inhibitor (Alisertib) in Solid Tumors

PURPOSE

The purpose of this study was to evaluate the rational combination of TORC1/2 inhibitor TAK-228 and Aurora A kinase inhibitor alisertib in preclinical models of triple-negative breast cancer (TNBC) and to conduct a phase I dose escalation trial in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

TNBC cell lines and patient-derived xenograft (PDX) models were treated with alisertib, TAK-228, or the combination and evaluated for changes in proliferation, cell cycle, mTOR pathway modulation, and terminal cellular fate, including apoptosis and senescence. A phase I clinical trial was conducted in patients with advanced solid tumors treated with escalating doses of alisertib and TAK-228 using a 3+3 design to determine the maximum tolerated dose (MTD).

RESULTS

The combination of TAK-228 and alisertib resulted in decreased proliferation and cell-cycle arrest in TNBC cell lines. Treatment of TNBC PDX models resulted in significant tumor growth inhibition and increased apoptosis with the combination. In the phase I dose escalation study, 18 patients with refractory solid tumors were enrolled. The MTD was alisertib 30 mg b.i.d. days 1 to 7 of a 21-day cycle and TAK-228 2 mg daily, continuous dosing. The most common treatment-related adverse events were neutropenia, fatigue, nausea, rash, mucositis, and alopecia.

CONCLUSIONS

The addition of TAK-228 to alisertib potentiates the antitumor activity of alisertib in vivo, resulting in increased cell death and apoptosis. The combination is tolerable in patients with advanced solid tumors and should be evaluated further in expansion cohorts with additional pharmacodynamic assessment.

A Biobank of Colorectal Cancer Patient-Derived Xenografts

Colorectal cancer (CRC) is a challenging disease, with a high mortality rate and limited effective treatment options, particularly for late-stage disease. Patient-derived xenografts (PDXs) have emerged as an informative, renewable experimental resource to model CRC architecture and biology. Here, we describe the generation of a biobank of CRC PDXs from stage I to stage IV patients. We demonstrate that PDXs within our biobank recapitulate the histopathological and mutation features of the original patient tumor. In addition, we demonstrate the utility of this resource in pre-clinical chemotherapy and targeted treatment studies, highlighting the translational potential of PDX models in the identification of new therapies that will improve the overall survival of CRC patients.

Wee1 Inhibition Enhances the Anti-Tumor Effects of Capecitabine in Preclinical Models of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype defined by lack of hormone receptor expression and non-amplified HER2. Adavosertib (AZD1775) is a potent, small-molecule, ATP-competitive inhibitor of the Wee1 kinase that potentiates the activity of many DNA-damaging chemotherapeutics and is currently in clinical development for multiple indications. The purpose of this study was to investigate the combination of AZD1775 and capecitabine/5FU in preclinical TNBC models. TNBC cell lines were treated with AZD1775 and 5FU and cellular proliferation was assessed in real-time using IncuCyte^® Live Cell Analysis. Apoptosis was assessed via the Caspase-Glo 3/7 assay system. Western blotting was used to assess changes in expression of downstream effectors. TNBC patient-derived xenograft (PDX) models were treated with AZD1775, capecitabine, or the combination and assessed for tumor growth inhibition. From the initial PDX screen, two of the four TNBC PDX models demonstrated a better response in the combination treatment than either of the single agents. As confirmation, two PDX models were expanded for statistical comparison. Both PDX models demonstrated a significant growth inhibition in the combination versus either of the single agents. (TNBC012, p < 0.05 combo vs. adavosertib or capecitabine, TNBC013, p < 0.01 combo vs. adavosertib or capecitabine.) An enhanced anti-proliferative effect was observed in the adavosertib/5FU combination treatment as measured by live cell analysis. An increase in apoptosis was observed in two of the four cell lines in the combination when compared to single-agent treatment. Treatment with adavosertib as a single agent resulted in a decrease in p-CDC2 in a dose-dependent manner that was also observed in the combination treatment. An increase in γH2AX in two of the four cell lines tested was also observed. No significant changes were observed in Bcl-xL following treatment in any of the cell lines. The combination of adavosertib and capecitabine/5FU demonstrated enhanced combination effects both in vitro and in vivo in preclinical models of TNBC. These results support the clinical investigation of this combination in patients with TNBC, including those with brain metastasis given the CNS penetration of both agents.

Selected by gene co-expression network and molecular docking analyses, ENMD-2076 is highly effective in glioblastoma-bearing rats

Background: Glioblastoma is the most common type of malignant brain tumor. Bioinformatics technology and structure biology were effectively and systematically used to identify specific targets in malignant tumors and screen potential drugs.

Results: GBM patients have higher AURKA and KDR mRNA expression compared with normal samples. Then, we identified a small molecular compound, ENMD-2076, could effectively inhibit Aurora kinase A and VEGFR-2 (encoded by KDR) activities. ENMD-2076 is predicted without toxic properties and also has absorption and gratifying brain/blood barrier penetration ability. Further results demonstrated that ENMD-2076 could significantly inhibit GBM cell lines proliferation and vitality, it also suppressed GBM cells migration and invasion. ENMD-2076 induced glioblastoma cell cycle arrest in G2-M phase and apoptosis by inhibiting PI3K/AKT/mTOR signaling pathways. Additionally, ENMD-2076 prolonged the median survival time of tumor-bearing rats and restrained growth rate of tumor volume in vivo.

Conclusions: Our findings reveal that ENMD-2076 is a promising drug in dealing with glioblastoma and have a perspective application.

Methods: We show that AURKA and KDR genes are hub driver genes in glioblastoma with bioinformatics technology including WGCNA analysis, PPI network, GO, KEGG analysis and GSEA analysis. After identifying a compound via virtual screening analysis, further experiments were carried out to examine the anti-glioblastoma activities of the compound in vivo and in vitro.

First-in-Class Phosphorylated-p68 Inhibitor RX-5902 Inhibits β-Catenin Signaling and Demonstrates Antitumor Activity in Triple-Negative Breast Cancer

RX-5902 is a first-in-class anticancer agent targeting phosphorylated-p68 and attenuating nuclear shuttling of β-catenin. The purpose of this study was to evaluate the efficacy of RX-5902 in preclinical models of triple-negative breast cancer (TNBC) and to explore effects on β-catenin expression. A panel of 18 TNBC cell lines was exposed to RX-5902, and changes in proliferation, apoptosis, cellular ploidy, and effector protein expression were assessed. Gene expression profiling was used in sensitive and resistant cell lines with pathway analysis to explore pathways associated with sensitivity to RX-5902. The activity of RX-5902 was confirmed in vivo in cell line and patient-derived tumor xenograft (PDX) models. RX-5902 demonstrated potent antiproliferative activity in vitro against TNBC cell lines with an average IC₅₀ of 56 nmol/L in sensitive cell lines. RX-5902 treatment resulted in the induction of apoptosis, G₂-M cell-cycle arrest, and aneuploidy in a subset of cell lines. RX-5902 was active in vivo against TNBC PDX models, and treatment resulted in a decrease in nuclear β-catenin. RX-5902 exhibited dose-proportional pharmacokinetics and plasma and tumor tissue in nude mice. Pathway analysis demonstrated an increase in the epithelial-to-mesenchymal transformation (EMT), TGFβ, and Wnt/β-catenin pathways associated with sensitivity to RX-5902. RX-5902 is active against in vitro and in vivo preclinical models of TNBC. Target engagement was confirmed with decreases in nuclear β-catenin and MCL-1 observed, confirming the proposed mechanism of action. This study supports the continued investigation of RX-5902 in TNBC and combinations with immunotherapy.

Aurora-A/ERK1/2/mTOR axis promotes tumor progression in triple-negative breast cancer and dual-targeting Aurora-A/mTOR shows synthetic lethality

Triple-negative breast cancer (TNBC), defined as a tumor subtype that lacks ER, PR, and HER2, shows a poor prognosis due to its aggressive tumor biology and limited treatment options. Deregulation of Aurora kinase A (Aur-A), a member of the mitotic serine/threonine Aurora kinase family, and overactivation of the mTOR pathway commonly occur in multiple cancer types. We previously found that Aur-A activated the mTOR pathway and inhibited autophagy activity in breast cancer cell models. Whether and how Aur-A regulates mTOR in TNBC are still unclear. Here, we found that Aur-A and p-mTOR are highly expressed and positively associated with each other in TNBC cells and tissues. Inhibition or knockdown of Aur-A decreased p-mTOR and suppressed cell proliferation and migration, whereas overexpression of Aur-A increased p-mTOR levels and promoted cell proliferation and migration, which was significantly abrogated by simultaneous silencing of mTOR. Intriguingly, overexpression of Aur-A enhanced the expression of p-mTOR and p-ERK1/2, and silencing or inhibition of ERK1/2 blocked Aur-A-induced p-mTOR. However, silencing or inhibition of mTOR failed to reverse Aur-A-induced ERK1/2, indicating that Aur-A/ERK1/2/mTOR forms an oncogenic cascade in TNBC. We finally found that double inhibition of Aur-A and mTOR showed significant synergistic effects in TNBC cell lines and a xenograft model, indicating that Aur-A and mTOR are potential therapeutic targets in the TNBC subtype.

Aurora kinase A stabilizes FOXM1 to enhance paclitaxel resistance in triple-negative breast cancer

Triple-negative breast cancer (TNBC) has a relatively poor outcome. Acquired chemoresistance is a major clinical challenge for TNBC patients. Previously, we reported that kinase-dead Aurora kinase A (Aurora-A) could effectively transactivate the FOXM1 promoter. Here, we demonstrate an additional pathway through which Aurora-A stabilizes FOXM1 by attenuating its ubiquitin in TNBC. Specifically, Aurora-A stabilizes FOXM1 in late M phase and early G1 phase of the cell cycle, which promotes proliferation of TNBC cells. Knock-down of Aurora-A significantly suppresses cell proliferation in TNBC cell lines and can be rescued by FOXM1 overexpression. We observe that paclitaxel-resistant TNBC cells exhibit high expression of Aurora-A and FOXM1. Overexpression of Aurora-A offers TNBC cells an additional growth advantage and protection against paclitaxel. Moreover, Aurora-A and FOXM1 could be simultaneously targeted by thiostrepton. Combination of thiostrepton and paclitaxel treatment reverses paclitaxel resistance and significantly inhibits cell proliferation. In conclusion, our study reveals additional mechanism through which Aurora-A regulates FOXM1 and provides a new therapeutic strategy to treat paclitaxel-resistant triple-negative breast cancer.

Overexpression of Uric Acid Transporter SLC2A9 Inhibits Proliferation of Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-associated mortality worldwide. Although the mechanisms of HCC progression are not well understood, recent studies demonstrated the potential contribution of uric acid transporter SLC2A9 to tumor suppression. However, the roles and underlying mechanisms are still unknown. We aimed to study the roles and mechanisms of SLC2A9 in HCC. The present study showed that SLC2A9 expression was decreased in human HCC tissues and cell lines. In addition, overexpression of SLC2A9 inhibited HCC cell proliferation. SCL2A9 induced HCC cell apoptosis by inhibiting the expression of caspase 3. Our study also revealed that upregulation of SLC2A9 reduced intracellular reactive oxygen species (ROS) accumulation. Furthermore, SLC2A9 increased the mRNA and protein expression of tumor suppressor p53 in HCC cells. Probenecid inhibits SLC2A9-mediated uric acid transport, which promotes cell proliferation, inhibits cell apoptosis, induces intracellular ROS, and decreases the expression of p53 in HCC cells. Therefore, the present study demonstrated that SLC2A9 may be a novel tumor suppressor gene and a potential therapeutic target in HCC.

Systematic Review of Patient-Derived Xenograft Models for Preclinical Studies of Anti-Cancer Drugs in Solid Tumors

Patient-derived xenograft (PDX) models are used as powerful tools for understanding cancer biology in PDX clinical trials and co-clinical trials. In this systematic review, we focus on PDX clinical trials or co-clinical trials for drug development in solid tumors and summarize the utility of PDX models in the development of anti-cancer drugs, as well as the challenges involved in this approach, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Recently, the assessment of drug efficacy by PDX clinical and co-clinical trials has become an important method. PDX clinical trials can be used for the development of anti-cancer drugs before clinical trials, with their efficacy assessed by the modified response evaluation criteria in solid tumors (mRECIST). A few dozen cases of PDX models have completed enrollment, and the efficacy of the drugs is assessed by 1 × 1 × 1 or 3 × 1 × 1 approaches in the PDX clinical trials. Furthermore, co-clinical trials can be used for personalized care or precision medicine with the evaluation of a new drug or a novel combination. Several PDX models from patients in clinical trials have been used to assess the efficacy of individual drugs or drug combinations in co-clinical trials.

Recent therapeutic trends and promising targets in triple negative breast cancer

Breast cancer accounts for 25% of all types of cancer in women, and triple negative breast cancer (TNBC) comprises around 15~20% of breast cancers. Conventional chemotherapy and radiation are the primary systemic therapeutic strategies; no other FDA-approved targeted therapies are yet available as for TNBC. TNBC is generally characterized by a poor prognosis and high rates of proliferation and metastases. Due to these aggressive features and lack of targeted therapies, numerous attempts have been made to discover viable molecular targets for TNBC. Massive cohort studies, clinical trials, and in-depth analyses have revealed diverse molecular alterations in TNBC; however, controversy exists as to whether many of these changes are beneficial or detrimental in caner progression. Here we review the complicated tumorigenic processes and discuss critical findings and therapeutic trends in TNBC with a focus on promising therapeutic approaches, the clinical trials currently underway, and potent experimental compounds under preclinical and evaluation.

A phase II clinical trial of the Aurora and angiogenic kinase inhibitor ENMD-2076 for previously treated, advanced, or metastatic triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) remains an aggressive breast cancer subtype with limited treatment options. ENMD-2076 is a small-molecule inhibitor of Aurora and angiogenic kinases with proapoptotic and antiproliferative activity in preclinical models of TNBC.

Methods

This dual-institution, single-arm, two-stage, phase II clinical trial enrolled patients with locally advanced or metastatic TNBC previously treated with one to three prior lines of chemotherapy in the advanced setting. Patients were treated with ENMD-2076 250 mg orally once daily with continuous dosing in 4-week cycles until disease progression or unacceptable toxicity occurred. The primary endpoint was 6-month clinical benefit rate (CBR), and secondary endpoints included progression-free survival, pharmacokinetic profile, safety, and biologic correlates in archival and fresh serial tumor biopsies in a subset of patients.

Results

Forty-one patients were enrolled. The 6-month CBR was 16.7% (95% CI, 6–32.8%) and included two partial responses. The 4-month CBR was 27.8% (95% CI, 14–45.2%), and the average duration of benefit was 6.5 cycles. Common adverse events included hypertension, fatigue, diarrhea, and nausea. Treatment with ENMD-2076 resulted in a decrease in cellular proliferation and microvessel density and an increase in p53 and p73 expression, consistent with preclinical observations.

Conclusions

Single-agent ENMD-2076 treatment resulted in partial response or clinical benefit lasting more than 6 months in 16.7% of patients with pretreated, advanced, or metastatic TNBC. These results support the development of predictive biomarkers using archival and fresh tumor tissue, as well as consideration of mechanism-based combination strategies.

Trial registration

ClinicalTrials.gov, NCT01639248. Registered on July 12, 2012.