Vismodegib y sonidegib en el carcinoma de células basales localmente avanzado y metastásico: actualización acerca de los inhibidores de la vía de Hedgehog / Vismodegib and Sonidegib in Locally Advanced and Metastatic Basal Cell Carcinoma: Update on Hedgehog Pathway Inhibitors

El carcinoma de células basales (CBC) es una de las neoplasias malignas más frecuentes, por lo que se ha convertido en una importante carga asistencial. Su incidencia se incrementa anualmente, especialmente en la población con mayor edad. A pesar de que generalmente está bien localizado, el CBC tiene la capacidad de destruir tejidos y evolucionar a un CBC localmente avanzado (CBCla) o incluso, aunque de forma más rara, a un CBC metastásico (CBCm). Las opciones terapéuticas convencionales en estos casos están bien establecidas, entre las cuales se incluyen la cirugía y la radioterapia. Sin embargo, no todos los casos son elegibles para realizar un tratamiento de tipo convencional. Recientemente, los tratamientos biológicos vienen ganando una mayor atención y son objeto de diversos estudios de investigación. De este modo se ha desarrollado una terapia dirigida utilizando los inhibidores de la vía de Hedgehog (IVH), teniendo en cuenta que se trata de una vía patogénica clave tanto en el CBCla como en el CBCm. En la actualidad, para poder tratar el CBCla y el CBCm no operables existen dos IVH aprobados: el vismodegib y el sonidegib. Esta revisión busca explorar la fisiopatología de la vía del Hedgehog responsable del desarrollo del CBC y hacer una actualización en cuanto a la eficacia, así como de las propiedades farmacocinéticas de los IVH, características que los convirtieron en la opción terapéutica ideal en el CBCla o en el CBCm, ya sea en forma de monoterapia o en combinación con alguno de los tratamientos convencionales (AU)

As one of the most common malignancies, basal cell carcinoma (BCC) has evolved as a global burden with incidence annually rising, especially in the older population. Even though the condition is mostly localized, the nature of the disease is destructive and can evolve as either locally advanced BCC (laBCC) or even more rarely as metastatic BCC (mBCC). There are well-established conventional treatment options for these cases, including surgeries and radiotherapy. However, not all cases are eligible for conventional treatments. Recently, biologic treatment has gained a lot of attention and research. This has led to the development of targeted treatment involving the hedgehog pathway inhibitor (HPI), a key pathogenesis in laBCC and mBCC. There are currently two approved HPIs, vismodegib and sonidegib to treat inoperable laBCC and mBCC. This review seeks to explore the pathophysiology of hedgehog pathway behind the development of BCC, and the current update of the efficacy as well as pharmacokinetics properties of HPIs that led to the ideal treatment for laBCC or mBCC, either as monotherapy or in combination with other conventional therapies (AU)

[Translated article] Vismodegib and Sonidegib in Locally Advanced and Metastatic Basal Cell Carcinoma: Update on Hedgehog Pathway Inhibitors / Vismodegib y sonidegib en el carcinoma de células basales localmente avanzado y metastásico: actualización acerca de los inhibidores de la vía de Hedgehog

As one of the most common malignancies, basal cell carcinoma (BCC) has evolved as a global burden with incidence annually rising, especially in the older population. Even though the condition is mostly localized, the nature of the disease is destructive and can evolve as either locally advanced BCC (laBCC) or even more rarely as metastatic BCC (mBCC). There are well-established conventional treatment options for these cases, including surgeries and radiotherapy. However, not all cases are eligible for conventional treatments. Recently, biologic treatment has gained a lot of attention and research. This has led to the development of targeted treatment involving the hedgehog pathway inhibitor (HPI), a key pathogenesis in laBCC and mBCC. There are currently two approved HPIs, vismodegib and sonidegib to treat inoperable laBCC and mBCC. This review seeks to explore the pathophysiology of hedgehog pathway behind the development of BCC, and the current update of the efficacy as well as pharmacokinetics properties of HPIs that led to the ideal treatment for laBCC or mBCC, either as monotherapy or in combination with other conventional therapies (AU)

El carcinoma de células basales (CBC) es una de las neoplasias malignas más frecuentes, por lo que se ha convertido en una importante carga asistencial. Su incidencia se incrementa anualmente, especialmente en la población con mayor edad. A pesar de que generalmente está bien localizado, el CBC tiene la capacidad de destruir tejidos y evolucionar a un CBC localmente avanzado (CBCla) o incluso, aunque de forma más rara, a un CBC metastásico (CBCm). Las opciones terapéuticas convencionales en estos casos están bien establecidas, entre las cuales se incluyen la cirugía y la radioterapia. Sin embargo, no todos los casos son elegibles para realizar un tratamiento de tipo convencional. Recientemente, los tratamientos biológicos vienen ganando una mayor atención y son objeto de diversos estudios de investigación. De este modo se ha desarrollado una terapia dirigida utilizando los inhibidores de la vía de Hedgehog (IVH), teniendo en cuenta que se trata de una vía patogénica clave tanto en el CBCla como en el CBCm. En la actualidad, para poder tratar el CBCla y el CBCm no operables existen dos IVH aprobados: el vismodegib y el sonidegib. Esta revisión busca explorar la fisiopatología de la vía del Hedgehog responsable del desarrollo del CBC y hacer una actualización en cuanto a la eficacia, así como de las propiedades farmacocinéticas de los IVH, características que los convirtieron en la opción terapéutica ideal en el CBCla o en el CBCm, ya sea en forma de monoterapia o en combinación con alguno de los tratamientos convencionales (AU)

The ECM Modulator ITIH5 Affects Cell Adhesion, Motility and Chemotherapeutic Response of Basal/Squamous-Like (BASQ) Bladder Cancer Cells.

This study aims at characterizing the role of the putative tumor suppressor ITIH5 in basal-type bladder cancers (BLCA). By sub-classifying TCGA BLCA data, we revealed predominant loss of ITIH5 expression in the basal/squamous-like (BASQ) subtype. ITIH5 expression inversely correlated with basal-type makers such as KRT6A and CD44. Interestingly, Kaplan-Meier analyses showed longer recurrence-free survival in combination with strong CD44 expression, which is thought to mediate ITIH-hyaluronan (HA) binding functions. In vitro, stable ITIH5 overexpression in two basal-type BLCA cell lines showing differential CD44 expression levels, i.e., with (SCaBER) and without squamous features (HT1376), demonstrated clear inhibition of cell and colony growth of BASQ-type SCaBER cells. ITIH5 further enhanced HA-associated cell-matrix attachment, indicated by altered size and number of focal adhesion sites resulting in reduced cell migration capacities. Transcriptomic analyses revealed enrichment of pathways and processes involved in ECM organization, differentiation and cell signaling. Finally, we provide evidence that ITIH5 increase sensitivity of SCaBER cells to chemotherapeutical agents (cisplatin and gemcitabine), whereas responsiveness of HT1376 cells was not affected by ITIH5 expression. Thus, we gain further insights into the putative role of ITIH5 as tumor suppressor highlighting an impact on drug response potentially via the HA-CD44 axis in BASQ-type BLCA.

One- and Two-Photon Phototherapeutic Effects of RuII Polypyridine Complexes in the Hypoxic Centre of Large Multicellular Tumor Spheroids and Tumor-Bearing Mice*.

During the last decades, photodynamic therapy (PDT), an approved medical technique, has received increasing attention to treat certain types of cancer. Despite recent improvements, the treatment of large tumors remains a major clinical challenge due to the low ability of the photosensitizer (PS) to penetrate a 3D cellular architecture and the low oxygen concentrations present in the tumor center. To mimic the conditions found in clinical tumors, exceptionally large 3D multicellular tumor spheroids (MCTSs) with a diameter of 800 µm were used in this work to test a series of new RuII polypyridine complexes as one-photon and two-photon PSs. These metal complexes were found to fully penetrate the 3D cellular architecture and to generate singlet oxygen in the hypoxic center upon light irradiation. While having no observed dark toxicity, the lead compound of this study showed an impressive phototoxicity upon clinically relevant one-photon (595 nm) or two-photon (800 nm) excitation with a full eradication of the hypoxic center of the MCTSs. Importantly, this efficacy was also demonstrated on mice bearing an adenocarcinomic human alveolar basal epithelial tumor.

Advanced basal cell cancer: concise review of molecular characteristics and novel targeted and immune therapeutics.

Metastatic basal cell carcinoma is an ultra-rare manifestation of a common disease, appearing in 0.0028%-0.5% of basal cell carcinomas. Initial therapeutic efforts focused on cytotoxic chemotherapy administration. However, it is now known that the Hedgehog signaling pathway is crucial for basal cell proliferation and Hedgehog pathway mutations may lead to tumorigenesis; thus, small-molecule inhibitors of alterations in the components of this pathway, including smoothened (SMO) and GLI, have been the focus of recent therapeutic developments. Indeed, the European Medicines Agency and the Food and Drug Administration have approved the SMO inhibitors, vismodegib and sonidegib, with additional GLI inhibitors currently in clinical trials. Molecular profiling of these tumors has revealed other potential targets for therapy, including high tumor mutational burden and PD-L1 amplification, which predict response to immune checkpoint blockade (PD-1 and PD-L1 inhibitors). An illustrative patient with a giant, advanced, unresectable basal cell carcinoma who obtained an ongoing complete remission after treatment with a combination of an immune checkpoint inhibitor (due to the tumor's high mutational burden) and the Hedgehog inhibitor vismodegib is described. A fuller understanding of the genomic portfolio of these patients can assist in developing novel, rational therapeutic approaches that should continue to improve responses and outcomes.

Respuesta al tratamiento con HeberFERON desde el diagnóstico de enfermería en pacientes con neoplasia basocelular / Response to Treatment with HeberFERON since the Nursing Diagnosis in Patients with Basal Cell Neoplasia

RESUMEN Introducción: En Cuba, la introducción del HeberFERON para el tratamiento de neoplasias de piel no melanomas perioculares ha permitido respuestas clínicas y estéticas muy favorables, evitando cirugías y reconstrucciones complejas, obteniéndose resultados muy promisorios. Objetivo: Describir la respuesta al tratamiento con HeberFERON en pacientes con neoplasia basocelular desde el diagnóstico de enfermería. Métodos: Estudio descriptivo longitudinal prospectivo en el Servicio de Oftalmología del Hospital General Docente Abel Santamaría Cuadrado de Pinar del Río en el periodo julio-diciembre 2017. El universo estuvo constituido por 12 pacientes con neoplasia basocelular, tratados con HeberFERON. Las variables analizadas fueron: edad, sexo, fototipo de piel, localización y tamaño de la lesión, respuesta al tratamiento, diagnóstico de enfermería. Resultados: El 50,00 por ciento de los pacientes estudiados pertenecieron al grupo de edades de 71 y más, de sexo masculino, y la lesión tenía un tamaño de menos de 20 mm, el 66,66 por ciento fototipo de piel II , la lesión se localizaba en el parpado inferior y tuvieron una respuesta completa al tratamiento con el HeberFERON, el diagnóstico de enfermería de desconfianza e insuficiente conocimiento de su enfermedad estuvo en el 100,00 por ciento de los casos , temor a la muerte en el 91,66 por ciento, y el deterioro de la piel y los tejidos adyacentes en un 83,33 por ciento de los casos estudiados. Conclusiones: La mayoría de los pacientes tratados con HeberFERON presentaron una respuesta completa a la terapéutica utilizada, traducido en una desaparición completa de la neoplasia(AU)

ABSTRACT Introduction: In Cuba, HeberFERON introduction in the treatment of non-melanomas periocular skin neoplasms has allowed very favorable clinical and aesthetic outcomes, avoiding complex surgeries and reconstructions and obtaining very promising results. Objective: To describe the response to HeberFERON treatment in patients with basal cell neoplasia since the nursing diagnosis. Methods: Prospective, longitudinal and descriptive study carried out in the ophthalmology service of Abel Santamaría Cuadrado General Teaching Hospital of Pinar del Río, in the period from July to December 2017. The study population consisted of 12 patients with basal cell neoplasia and treated with HeberFERON. The variables analyzed were age, sex, skin phototype, location and size of the lesion, response to treatment, and nursing diagnosis. Results: 50.00 percent of the patients studied belonged to the age group of 71 years or older, of male sex, and whose lesion was less than 20 mm in size. 66.66 percent had a skin phototype II. The lesion was located in the lower eyelid and had a complete response to treatment with HeberFERON. Based on the nursing diagnosis, lack of confidence and knowledge about the disease was in 100 percent of the cases; fear of death, in 91.66 percent; deterioration of skin and tissues around, in 83.33 percent. Conclusions: The majority of the patients treated with HeberFERON presented a complete response to the therapy, resulting in a total disappearance of the neoplasm(AU)

Histamine receptor 1 inhibition enhances antitumor therapeutic responses through extracellular signal-regulated kinase (ERK) activation in breast cancer.

Histamine receptor 1 (HRH1) belongs to the rhodopsin-like G-protein-coupled receptor family. Its activation by histamine triggers cell proliferation, embryonic development, and tumor growth. We recently established that HRH1 is up-regulated in basal and human epidermal growth factor receptor 2 (HER2)-enriched human breast tumors and that its expression correlates with a worse prognosis. Nevertheless, the functional role of HRH1 in basal and HER2-targeted therapy-resistant breast cancer (BC) progression has not yet been addressed. Using terfenadine, a selective chemical inhibitor of HRH1, we showed that the inhibition of HRH1 activity in basal BC cells leads to sub-G0 cell accumulation, suppresses proliferation, promotes cell motility and triggers the activation of extracellular signal-regulated kinase (ERK) signaling, initiating the mitochondrial apoptotic pathway. Furthermore, HER2-targeted therapy-resistant cells express higher levels of HRH1 and are more sensitive to terfenadine treatment. Moreover, in vivo experiments showed that terfenadine therapy reduced the tumor growth of basal and trastuzumab-resistant BC cells. In conclusion, our results suggest that targeting HRH1 is a promising new clinical approach to consider that could enhance the effectiveness of current therapeutic treatment in patients with basal and BC tumors resistant to HER2-targeted therapies.

Molecular pathogenesis of human prostate basal cell hyperplasia.

BACKGROUND: Understanding the molecular pathogenesis of distinct phenotypes in human benign prostatic hyperplasia (BPH) is essential to improving therapeutic intervention. Current therapies target smooth muscle and luminal epithelia for relief of lower urinary tract symptoms (LUTS) due to BPH, but basal cell hyperplasia (BCH) remains untargeted. The incidence of has been reported at 8-10%, but a molecular and cellular characterization has not been performed on this phenotype. METHODS: Using freshly digested tissue from surgical specimens, we performed RNA-seq analysis of flow cytometry-purified basal epithelia from 3 patients with and 4 patients without a majority BCH phenotype. qPCR was performed on 28 genes identified as significant from 13 non-BCH and 7 BCH specimens to confirm transcriptomic analysis. IHC was performed on several non-BCH and BCH specimens for 3 proteins identified as significant by transcriptomic analysis. RESULTS: A total of 141 human BPH specimens were analyzed for the presence of BCH. Clinical characteristics of non-BCH and BCH cohorts revealed no significant differences in age, PSA, prostate volume, medical treatment, or comorbidities. Quantitation of cellular subsets by flow cytometry in 11 BCH patients vs. 11 non-BCH patients demonstrated a significant increase in the ratio of basal to luminal epithelia in patients with BCH (P <0.05), but no significant differences in the total number of leukocytes. RNA-seq data from flow cytometry isolated basal epithelia from patients with and without BCH were subjected to gene set enrichment analysis of differentially expressed genes, which revealed increased expression of members of the epidermal differentiation complex. Transcriptomic data were complemented by immunohistochemistry for members of the epidermal differentiation complex, revealing a morphological similarity to other stratified squamous epithelial layers. CONCLUSIONS: Increased expression of epidermal differentiation complex members and altered epithelial stratification resembles the progression of other metaplastic diseases. These data provide insight into the plasticity of the human prostate epithelium and suggest a classification of basal cell hyperplasia as a metaplasia.

Anti-vascular effects of the cytosolic phospholipase A2 inhibitor AVX235 in a patient-derived basal-like breast cancer model.

BACKGROUND: Group IVA cytosolic phospholipase A2 (cPLA2α) plays an important role in tumorigenesis and angiogenesis. It is overexpressed in basal-like breast cancer (BLBC), which is aggressive and usually triple-negative, making it unresponsive to current targeted therapies. Here, we evaluated the anti-angiogenic effects of a specific cPLA2α inhibitor, AVX235, in a patient-derived triple-negative BLBC model. METHODS: Mice bearing orthotopic xenografts received i.p. injections of AVX235 or DMSO vehicle daily for 1 week and then every other day for up to 19 days. Six treated and six control mice were terminated after 2 days of treatment, and the tumors excised for high resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS) and prostaglandin E2 (PGE2) enzyme immunoassay (EIA) analysis. A 1-week imaging study was performed on a separate cohort of mice. Longitudinal dynamic contrast enhanced (DCE)-MRI was performed before, after 4 days, and after 1 week of treatment. The mice were then perfused with a radiopaque vascular casting agent, and the tumors excised for micro-CT angiography. Subsequently, tumors were sectioned and stained with lectin and for Ki67 or α-smooth muscle actin to quantify endothelial cell proliferation and vessel maturity, respectively. Partial least squares discriminant analysis was performed on the multivariate HR MAS MRS data, and non-parametric univariate analyses using Mann-Whitney U tests (α = 0.05) were performed on all other data. RESULTS: Glycerophosphocholine and PGE2 levels, measured by HR MAS MRS and EIA, respectively, were lower in treated tumors after 2 days of treatment. These molecular changes are expected downstream effects of cPLA2α inhibition and were followed by significant tumor growth inhibition after 8 days of treatment. DCE-MRI revealed that AVX235 treatment caused a decrease in tumor perfusion. Concordantly, micro-CT angiography showed that vessel volume fraction, density, and caliber were reduced in treated tumors. Moreover, histology showed decreased endothelial cell proliferation and fewer immature vessels in treated tumors. CONCLUSIONS: These results demonstrate that cPLA2α inhibition with AVX235 resulted in decreased vascularization and perfusion and subsequent inhibition of tumor growth. Thus, cPLA2α inhibition may be a potential new therapeutic option for triple-negative basal-like breast cancer.

LSD1 overexpression is associated with poor prognosis in basal-like breast cancer, and sensitivity to PARP inhibition.

LSD1, a lysine-specific histone demethylase, is overexpressed in several types of cancers and linked to poor outcomes. In breast cancer, the significance of LSD1 overexpression is not clear. We have performed an in silico analysis to assess the relationship of LSD1 expression to clinical outcome. We demonstrate that LSD1 overexpression is a poor prognostic factor in breast cancer, especially in basal-like breast cancer, a subtype of breast cancer with aggressive clinical features. This link is also observed in samples of triple negative breast cancer. Interestingly, we note that overexpression of LSD1 correlates with down-regulation of BRCA1 in triple negative breast cancer. This phenomenon is also observed in in vitro models of basal-like breast cancer, and is associated with an increased sensitivity to PARP inhibitors. We propose therefore that high expression levels of the demethylase LSD1 is a potential prognostic factor of poor outcome in basal-like breast cancer, and that PARP inhibition may be a therapeutic strategy of interest in this poor prognostic subtype with overexpression of LSD1.

Chemogenetic evaluation of the mitotic kinesin CENP-E reveals a critical role in triple-negative breast cancer.

Breast cancer patients with tumors lacking the three diagnostic markers (ER, PR, and HER2) are classified as triple-negative (primarily basal-like) and have poor prognosis because there is no disease-specific therapy available. To address this unmet medical need, gene expression analyses using more than a thousand breast cancer samples were conducted, which identified elevated centromere protein E (CENP-E) expression in the basal-a molecular subtype relative to other subtypes. CENP-E, a mitotic kinesin component of the spindle assembly checkpoint, is shown to be induced in basal-a tumor cell lines by the mitotic spindle inhibitor drug docetaxel. CENP-E knockdown by inducible shRNA reduces basal-a breast cancer cell viability. A potent, selective CENP-E inhibitor (PF-2771) was used to define the contribution of CENP-E motor function to basal-like breast cancer. Mechanistic evaluation of PF-2771 in basal-a tumor cells links CENP-E-dependent molecular events (e.g., phosphorylation of histone H3 Ser-10; phospho-HH3-Ser10) to functional outcomes (e.g., chromosomal congression defects). Across a diverse panel of breast cell lines, CENP-E inhibition by PF-2771 selectively inhibits proliferation of basal breast cancer cell lines relative to premalignant ones and its response correlates with the degree of chromosomal instability. Pharmacokinetic-pharmacodynamic efficacy analysis in a basal-a xenograft tumor model shows that PF-2771 exposure is well correlated with increased phospho-HH3-Ser10 levels and tumor growth regression. Complete tumor regression is observed in a patient-derived, basal-a breast cancer xenograft tumor model treated with PF-2771. Tumor regression is also observed with PF-2771 in a taxane-resistant basal-a model. Taken together, CENP-E may be an effective therapeutic target for patients with triple-negative/basal-a breast cancer.

Sanguinarine suppresses basal-like breast cancer growth through dihydrofolate reductase inhibition.

Basal-like breast cancer (BLBC) remains a great challenge because of its clinically aggressive nature and lack of effective targeted therapy. We analyzed the potential anti-neoplastic effects of sanguinarine, a natural benzophenanthridine alkaloid, against BLBC cells. Sanguinarine treatment resulted in a reduction of cell migration, in a dose-dependent inhibition of cell viability and in the induction of cell death by apoptosis in both human (MDA-MB-231 cells) and mouse (A17 cells) in vitro models of BLBC. In vivo experiments demonstrated that oral administration of sanguinarine reduced the development and growth of A17 transplantable tumors in FVB syngeneic mice. Western blotting analysis revealed that suppression of BLBC growth by sanguinarine was correlated with a concurrent upregulation of p27 and downregulation of cyclin D1 and with the inhibition of STAT3 activation. In addition, we identified sanguinarine as a potent inhibitor of dihydrofolate reductase (DHFR), able to impair enzyme activity even in methotrexate resistant MDA-MB-231 cells. These results provide evidence that sanguinarine is a promising anticancer drug for the treatment of BLBC.

Sumoylation pathway is required to maintain the basal breast cancer subtype.

The TFAP2C/AP-2γ transcription factor regulates luminal breast cancer genes, and loss of TFAP2C induces epithelial-mesenchymal transition. By contrast, the highly homologous family member, TFAP2A, lacks transcriptional activity at luminal gene promoters. A detailed structure-function analysis identified that sumoylation of TFAP2A blocks its ability to induce the expression of luminal genes. Disruption of the sumoylation pathway by knockdown of sumoylation enzymes, mutation of the SUMO-target lysine of TFAP2A, or treatment with sumoylation inhibitors induced a basal-to-luminal transition, which was dependent on TFAP2A. Sumoylation inhibitors cleared the CD44(+/hi)/CD24(-/low) cell population characterizing basal cancers and inhibited tumor outgrowth of basal cancer xenografts. These findings establish a critical role for sumoylation in regulating the transcriptional mechanisms that maintain the basal cancer phenotype.

MET is a potential target for use in combination therapy with EGFR inhibition in triple-negative/basal-like breast cancer.

MET, a cell surface receptor for hepatocyte growth factor, is involved in the development of triple-negative/basal-like breast cancer (TNBC/BLBC). However, its utility as a therapeutic target in this subtype of breast cancer is poorly understood. To evaluate MET fully as a potential therapeutic target for TNBC/BLBC, we investigated the relationship between MET expression and clinical outcomes of patients with breast cancer and the functional effect of MET inhibition. Using automated immunohistochemistry (Ventana), we analyzed MET expression in 924 breast cancer patients with relevant clinicopathologic parameters. BLBC showed the strongest relationship with MET expression (57.5%, p < 0.001). High expression of MET in breast cancer resulted in poor overall survival (p = 0.001) and disease-free survival (DFS, p = 0.010). MET expression was relatively high in TNBC cell lines, and the silencing of MET via small interfering RNA reduced cell proliferation and migration. We observed reduced TNBC cell viability after treatment with the MET inhibitor PHA-665752. In the most drug-resistant cell line, MDA-MB-468, which showed elevated epidermal growth factor receptor (EGFR) expression, silencing of EGFR resulted in increased sensitivity to PHA-665752 treatment. We confirmed that PHA-665752 synergizes with the EGFR inhibitor erlotinib to decrease the viability of MDA-MB-468 cells. TNBC patients coexpressing MET and EGFR showed significantly worse DFS than that in patients expressing EGFR alone (p = 0.021). Our findings strongly suggest that MET may be a therapeutic target in TNBC and that the combined therapy targeting MET and EGFR may be beneficial for the treatment of TNBC/BLBC patients.

Antitumor activity of the glutaminase inhibitor CB-839 in triple-negative breast cancer.

Glutamine serves as an important source of energy and building blocks for many tumor cells. The first step in glutamine utilization is its conversion to glutamate by the mitochondrial enzyme glutaminase. CB-839 is a potent, selective, and orally bioavailable inhibitor of both splice variants of glutaminase (KGA and GAC). CB-839 had antiproliferative activity in a triple-negative breast cancer (TNBC) cell line, HCC-1806, that was associated with a marked decrease in glutamine consumption, glutamate production, oxygen consumption, and the steady-state levels of glutathione and several tricarboxylic acid cycle intermediates. In contrast, no antiproliferative activity was observed in an estrogen receptor-positive cell line, T47D, and only modest effects on glutamine consumption and downstream metabolites were observed. Across a panel of breast cancer cell lines, GAC protein expression and glutaminase activity were elevated in the majority of TNBC cell lines relative to receptor positive cells. Furthermore, the TNBC subtype displayed the greatest sensitivity to CB-839 treatment and this sensitivity was correlated with (i) dependence on extracellular glutamine for growth, (ii) intracellular glutamate and glutamine levels, and (iii) GAC (but not KGA) expression, a potential biomarker for sensitivity. CB-839 displayed significant antitumor activity in two xenograft models: as a single agent in a patient-derived TNBC model and in a basal like HER2(+) cell line model, JIMT-1, both as a single agent and in combination with paclitaxel. Together, these data provide a strong rationale for the clinical investigation of CB-839 as a targeted therapeutic in patients with TNBC and other glutamine-dependent tumors.

Effect of niclosamide on basal-like breast cancers.

Basal-like breast cancers (BLBC) are poorly differentiated and display aggressive clinical behavior. These tumors become resistant to cytotoxic agents, and tumor relapse has been attributed to the presence of cancer stem cells (CSC). One of the pathways involved in CSC regulation is the Wnt/ß-catenin signaling pathway. LRP6, a Wnt ligand receptor, is one of the critical elements of this pathway and could potentially be an excellent therapeutic target. Niclosamide has been shown to inhibit the Wnt/ß-catenin signaling pathway by causing degradation of LRP6. TRA-8, a monoclonal antibody specific to TRAIL death receptor 5, is cytotoxic to BLBC cell lines and their CSC-enriched populations. The goal of this study was to examine whether niclosamide is cytotoxic to BLBCs, specifically the CSC population, and if in combination with TRA-8 could produce increased cytotoxicity. Aldehyde dehydrogenase (ALDH) is a known marker of CSCs. By testing BLBC cells for ALDH expression by flow cytometry, we were able to isolate a nonadherent population of cells that have high ALDH expression. Niclosamide showed cytotoxicity against these nonadherent ALDH-expressing cells in addition to adherent cells from four BLBC cell lines: 2LMP, SUM159, HCC1187, and HCC1143. Niclosamide treatment produced reduced levels of LRP6 and ß-catenin, which is a downstream Wnt/ß-catenin signaling protein. The combination of TRA-8 and niclosamide produced additive cytotoxicity and a reduction in Wnt/ß-catenin activity. Niclosamide in combination with TRA-8 suppressed growth of 2LMP orthotopic tumor xenografts. These results suggest that niclosamide or congeners of this agent may be useful for the treatment of BLBC.

Proteomic characterization of breast cancer xenografts identifies early and late bevacizumab-induced responses and predicts effective drug combinations.

PURPOSE: Neoangiogenesis is an important feature in tumor growth and progression, and combining chemotherapy and antiangiogenic drugs have shown clinical efficacy. However, as treatment-induced resistance often develops, our goal was to identify pathways indicating response and/or evolving resistance to treatment and inhibit these pathways to optimize the treatment strategies. EXPERIMENTAL DESIGN: To identify markers of response and/or resistance, reverse-phase protein array (RPPA) was used to characterize treatment-induced changes in a bevacizumab-responsive and a nonresponsive human breast cancer xenograft. Results were combined with bioinformatic modeling to predict druggable targets for optimization of the treatment. RESULTS: RPPA analysis showed that both tumor models responded to bevacizumab with an early (day 3) upregulation of growth factor receptors and downstream signaling pathways, with persistent mTOR signaling until the end of the in vivo experiment. Adding doxorubicin to bevacizumab showed significant and superior growth inhibition of basal-like tumors, whereas no additive effect was seen in the luminal-like model. The combination treatment corresponded to a continuous late attenuation of mTOR signaling in the basal-like model, whereas the inhibition was temporary in the luminal-like model. Integrating the bevacizumab-induced dynamic changes in protein levels with bioinformatic modeling predicted inhibition of phosphoinositide 3-kinase (PI3K) pathway to increase the efficacy of bevacizumab monotherapy. In vivo experiments combining bevacizumab and the PI3K/mTOR inhibitor BEZ235 confirmed their significant and additive growth-inhibitory effect in the basal-like model. CONCLUSIONS: Treatment with bevacizumab caused compensatory upregulation of several signaling pathways. Targeting such pathways increased the efficacy of antiangiogenic therapy.

Manganese superoxide dismutase is a promising target for enhancing chemosensitivity of basal-like breast carcinoma.

AIMS: Although earlier reports highlighted a tumor suppressor role for manganese superoxide dismutase (MnSOD), recent evidence indicates increased expression in a variety of human cancers including aggressive breast carcinoma. In the present article, we hypothesized that MnSOD expression is significantly amplified in the aggressive breast carcinoma basal subtype, and targeting MnSOD could be an attractive strategy for enhancing chemosensitivity of this highly aggressive breast cancer subtype. RESULTS: Using MDA-MB-231 and BT549 as a model of basal breast cancer cell lines, we show that knockdown of MnSOD decreased the colony-forming ability and sensitized the cells to drug-induced cell death, while drug resistance was associated with increased MnSOD expression. In an attempt to develop a clinically relevant approach to down-regulate MnSOD expression in patients with basal breast carcinoma, we employed activation of the peroxisome proliferator-activated receptor gamma (PPARγ) to repress MnSOD expression; PPARγ activation significantly reduced MnSOD expression, increased chemosensitivity, and inhibited tumor growth. Moreover, as a proof of concept for the clinical use of PPARγ agonists to decrease MnSOD expression, biopsies derived from breast cancer patients who had received synthetic PPARγ ligands as anti-diabetic therapy had significantly reduced MnSOD expression. Finally, we provide evidence to implicate peroxynitrite as the mechanism involved in the increased sensitivity to chemotherapy induced by MnSOD repression. INNOVATION AND CONCLUSION: These data provide evidence to link increased MnSOD expression with the aggressive basal breast cancer, and underscore the judicious use of PPARγ ligands for specifically down-regulating MnSOD to increase the chemosensitivity of this subtype of breast carcinoma.