buparlisib and Triple-Negative-Breast-Neoplasms

Treatment options for triple-negative breast cancer remain limited. Activation of the PI3K pathway via loss of PTEN and/or INPP4B is common. Buparlisib is an orally bioavailable, pan-class I PI3K inhibitor. We evaluated the safety and efficacy of buparlisib in patients with metastatic triple-negative breast cancer.. This was a single-arm phase 2 study enrolling patients with triple-negative metastatic breast cancer. Patients were treated with buparlisib at a starting dose of 100 mg daily. The primary endpoint was clinical benefit, defined as confirmed complete response (CR), partial response (PR), or stable disease (SD) for ≥ 4 months, per RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity. A subset of patients underwent pre- and on-treatment tumor tissue biopsies for correlative studies.. Fifty patients were enrolled. Median number of cycles was 2 (range 1-10). The clinical benefit rate was 12% (6 patients, all SD ≥ 4 months). Median PFS was 1.8 months (95% confidence interval [CI] 1.6-2.3). Median OS was 11.2 months (95% CI 6.2-25). The most frequent adverse events were fatigue (58% all grades, 8% grade 3), nausea (34% all grades, none grade 3), hyperglycemia (34% all grades, 4% grade 3), and anorexia (30% all grades, 2% grade 3). Eighteen percent of patients experienced depression (12% grade 1, 6% grade 2) and anxiety (10% grade 1, 8% grade 2). Alterations in PIK3CA/AKT1/PTEN were present in 6/27 patients with available targeted DNA sequencing (MSK-IMPACT), 3 of whom achieved SD as best overall response though none with clinical benefit ≥ 4 months. Of five patients with paired baseline and on-treatment biopsies, reverse phase protein arrays (RPPA) analysis demonstrated reduction of S6 phosphorylation in 2 of 3 patients who achieved SD, and in none of the patients with progressive disease.. Buparlisib was associated with prolonged SD in a very small subset of patients with triple-negative breast cancer; however, no confirmed objective responses were observed. Downmodulation of key nodes in the PI3K pathway was observed in patients who achieved SD. PI3K pathway inhibition alone may be insufficient as a therapeutic strategy for triple-negative breast cancer.. NCT01790932 . Registered on 13 February 2013; NCT01629615 . Registered on 27 June 2012.

Topics: Adult; Aged; Aminopyridines; Antineoplastic Combined Chemotherapy Protocols; Class I Phosphatidylinositol 3-Kinases; Disease Progression; Female; High-Throughput Nucleotide Sequencing; Humans; Middle Aged; Morpholines; Neoplasm Metastasis; Patient Safety; Protein Kinase Inhibitors; Proteomics; Response Evaluation Criteria in Solid Tumors; Survival Rate; Treatment Outcome; Triple Negative Breast Neoplasms

The identification of patients with homologous recombination deficiency (HRD) beyond BRCA1/2 mutations is an urgent task, as they may benefit from PARP inhibitors. We have previously developed a method to detect mutational signature 3 (Sig3), termed SigMA, associated with HRD from clinical panel sequencing data, that is able to reliably detect HRD from the limited sequencing data derived from gene-focused panel sequencing.. We apply this method to patients from two independent datasets: (i) high-grade serous ovarian cancer and triple-negative breast cancer (TNBC) from a phase Ib trial of the PARP inhibitor olaparib in combination with the PI3K inhibitor buparlisib (BKM120; NCT01623349), and (ii) TNBC patients who received neoadjuvant olaparib in the phase II PETREMAC trial (NCT02624973).. We find that Sig3 as detected by SigMA is positively associated with improved progression-free survival and objective responses. In addition, comparison of Sig3 detection in panel and exome-sequencing data from the same patient samples demonstrated highly concordant results and superior performance in comparison with the genomic instability score.. Our analyses demonstrate that HRD can be detected reliably from panel-sequencing data that are obtained as part of routine clinical care, and that this approach can identify patients beyond those with germline BRCA1/2mut who might benefit from PARP inhibitors. Prospective clinical utility testing is warranted.

Topics: BRCA1 Protein; BRCA2 Protein; Female; Homologous Recombination; Humans; Mutation; Ovarian Neoplasms; Phosphatidylinositol 3-Kinases; Poly(ADP-ribose) Polymerase Inhibitors; Prospective Studies; Triple Negative Breast Neoplasms

Co-targeting PARP and PI3K by PARP/PI3K dual inhibitors has been recognized as a promising chemotherapeutic strategy for the treatment of triple negative breast cancer (TNBC) in our previous work. To further explore novel and more potent PARP/PI3K dual inhibitors, a series of compounds were designed, synthesized and evaluated for their pharmacological properties, resulting in the candidate compound 12, a potent and highly selective PARP/PI3K dual inhibitor. Compared to Olaparib, compound 12 exhibits a superior antiproliferative profile against BRCA-proficient MDA-MB-468 cells. In MDA-MB-468 cell-derived xenograft model, compound 12 displayed excellent antitumor efficacy at a dose of 50 mg/kg, which is considerably more efficacious than the single administration of Olaparib or BKM120. Furthermore, compound 12 displayed good metabolic stability and high safety. Taken together, these results suggest that compound 12 as a novel PARP/PI3K dual inhibitor is worthy for further study.

Topics: Aminopyridines; Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; Drug Synergism; Humans; Male; Mice; Mice, Inbred BALB C; Models, Molecular; Molecular Docking Simulation; Molecular Targeted Therapy; Morpholines; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phthalazines; Piperazines; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Protein Binding; Solubility; Structure-Activity Relationship; Triple Negative Breast Neoplasms

Poly (ADP-ribose) polymerase (PARP) inhibitors offer a significant clinical benefit for triple-negative breast cancers (TNBCs) with BRCA1/2 mutation. However, the narrow clinical indication limits the development of PARP inhibitors. Phosphoinositide 3-kinase (PI3K) inhibition sensitizes BRCA-proficient TNBC to PARP inhibition, which broadens the indication of PARP inhibitors. Previously researches have reported that PI3K inhibition induced the defect of homologous recombination (HR) mediated repair by downregulating the expression of BRCA1/2 and Rad51. However, the mechanism for their synergistic effects in the treatment of TNBC is still unclear. Herein, we focused on DNA damage, DNA single-strand breaks (SSBs) repair and DNA double-strand breaks (DSBs) repair three aspects to investigate the mechanism of dual PI3K and PARP inhibition in DNA damage response. We found that dual PI3K and PARP inhibition with BKM120 and olaparib significantly reduced the proliferation of BRCA-proficient TNBC cell lines MDA-MB-231 and MDA231-LM2. BKM120 increased cellular ROS to cause DNA oxidative damage. Olaparib resulted in concomitant gain of PARP1, forkhead box M1 (FOXM1) and Exonuclease 1 (Exo1) while inhibited the activity of PARP. BKM120 downregulated the expression of PARP1 and PARP2 to assist olaparib in blocking PARP mediated repair of DNA SSBs. Meanwhile, BKM120 inhibited the expression of BRAC1/2 and Rad51/52 to block HR mediated repair through the PI3K/Akt/NFκB/c-Myc signaling pathway and PI3K/Akt/ FOXM1/Exo1 signaling pathway. BKM120 induced HR deficiency expanded the application of olaparib to HR proficient TNBCs. Our findings proved that PI3K inhibition impaired the repair of both DNA SSBs and DNA DSBs. FOXM1 and Exo1 are novel therapeutic targets that serves important roles in DNA damage response.

Topics: Aminopyridines; Antineoplastic Agents; BRCA1 Protein; BRCA2 Protein; Cell Line, Tumor; DNA Repair Enzymes; Exodeoxyribonucleases; Female; Forkhead Box Protein M1; Gene Expression Regulation, Neoplastic; Humans; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Phthalazines; Piperazines; Triple Negative Breast Neoplasms

Topics: Aminopyridines; Animals; Apoptosis; Ascorbic Acid; Cell Line, Tumor; Drug Synergism; Female; Gene Expression Regulation, Neoplastic; Histone Code; Humans; Mice; Mice, Inbred NOD; Mice, SCID; Molecular Targeted Therapy; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Precision Medicine; Triple Negative Breast Neoplasms; Xenograft Model Antitumor Assays

Fusion genes can be therapeutically relevant if they result in constitutive activation of oncogenes or repression of tumor suppressors. However, the prevalence and role of fusion genes in female cancers remain largely unexplored. Here, we investigate the fusion gene landscape in triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSOC), two subtypes of female cancers with high molecular similarity but limited treatment options at present.. RNA-seq was utilized to identify fusion genes in a cohort of 18 TNBC and HGSOC patients treated with the PI3K inhibitor buparlisib and the PARP inhibitor olaparib in a phase I clinical trial (NCT01623349). Differential gene expression analysis was performed to assess the function of fusion genes in silico. Finally, these findings were correlated with the reported clinical outcomes.. A total of 156 fusion genes was detected, whereof 44/156 (28%) events occurred in more than one patient. Low recurrence across samples indicated that the majority of fusion genes were private passenger events. The long non-coding RNA MALAT1 was involved in 97/156 (62%) fusion genes, followed in prevalence by MUC16, FOXP1, WWOX and XIST. Gene expression of FOXP1 was significantly elevated in patients with vs. without FOXP1 fusion (P= 0.02). From a clinical perspective, FOXP1 fusions were associated with a favorable overall survival.. In summary, this study provides the first characterization of fusion genes in a cohort of TNBC and HGSOC patients. An improved mechanistic understanding of fusion genes will support the future identification of innovative therapeutic approaches for these challenging diseases.

Topics: Adult; Aged; Aminopyridines; Antineoplastic Combined Chemotherapy Protocols; Clinical Trials, Phase I as Topic; Cystadenocarcinoma, Serous; Female; Forkhead Transcription Factors; Gene Expression Profiling; Gene Fusion; Humans; Middle Aged; Morpholines; Ovarian Neoplasms; Phthalazines; Piperazines; Repressor Proteins; RNA-Seq; Triple Negative Breast Neoplasms

Triple‑negative breast cancer (TNBC) refers to a heterogeneous group of tumors, for which there is currently a lack of targeted therapies. Poly(ADP‑ribose) polymerase (PARP) inhibitors, phosphatidylinositol 3‑kinase (PI3K) inhibitors and carboplatin (CBP) have demonstrated sufficient efficacy and safety for their use as individual drugs for the treatment of TNBC; however, their effects on TNBC when used as a combination have not been investigated. The primary objectives of the present study were to determine the effects of a combination of CBP, olaparib and NVP‑BKM120 (BKM120), and to investigate the mechanism underlying their effects on TNBC cells. The drug combination was cytotoxic to TNBC cells, both with regards to short‑term and long‑term sensitivity, as determined using colony forming assays, and they exerted strong synergistic effects on MDA‑MB‑231 and CAL51 cell lines. All drugs affected cell cycle progression, and western blotting and immunofluorescence indicated that the the drug combination exerted its cytotoxicity via DNA damage, enhancing non‑homologous end joining repair and inhibiting homologous recombination repair. These data provide a strong rationale to explore the therapeutic use of olaparib in combination with CBP and BKM120 in animal models, and later in clinical trials on patients with TNBC.

Topics: Aminopyridines; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA End-Joining Repair; DNA Repair; Drug Synergism; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; Morpholines; Phthalazines; Piperazines; Triple Negative Breast Neoplasms

Deregulation of the phosphatidylinositol-3-kinase (PI3K)/Akt signalling pathway is common in breast cancer and is frequently associated with resistance to both traditional chemotherapy and targeted drugs. There is a growing body of evidence indicating that a small subpopulation of self-renewing cells, the so called cancer stem cells (CSC), are responsible for the growth of drug resistant secondary tumors. As many CSCs have upregulated the PI3K/Akt signalling pathway, preclinical and clinical studies are addressing the inhibition of this axis to target drug resistance. We evaluated the susceptibility of breast CSCs to NVP-BKM120 (BKM120), a new generation of PI3K-specific inhibitor, when used individually or in combination with trastuzumab or RAD001 both in vitro and in vivo. For this, a stem-like cell population (SC) was enriched from breast cancer cell lines after mammosphere cultures. We demonstrated that BKM120 inhibits growth, generation of drug-resistant derivatives and SC formation in a panel of four breast cancer cell lines: MCF-7, MDA-MB-231, SK-BR-3 and CAL51. Importantly, BKM120 inhibits the PI3K/Akt signalling pathway in SCs from these cell lines. When BKM120 was used in combination with trastuzumab, a targeted therapy to treat HER2-positive breast cancer, we found synergistic cell growth inhibition, generation of drug resistant cells as well as SC formation from SK-BR-3 cells. Importantly, SK-BR-3 xenograft-derived tumors showed marginal growth when the drug combination was used. We also found a similar synergistic anticancer effect of BKM120 in combination with RAD001, an mTOR inhibitor, when treating triple-negative breast cancer cells in vitro and in both MDA-MB-231 and CAL51- mouse xenografts. Moreover, mouse data indicate that these drug combinations are well tolerated and provide the proof-of-concept and rationale to initiate clinical trials in both HER2-positive and triple-negative breast cancer.

Topics: Aminopyridines; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Humans; MCF-7 Cells; Mice; Mice, Nude; Morpholines; Neoplastic Stem Cells; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Receptor, ErbB-2; Signal Transduction; Trastuzumab; Triple Negative Breast Neoplasms; Xenograft Model Antitumor Assays

We previously reported that combining a phosphoinositide 3-kinase (PI3K) inhibitor with a poly-ADP Rib polymerase (PARP)-inhibitor enhanced DNA damage and cell death in breast cancers that have genetic aberrations in BRCA1 and TP53. Here, we show that enhanced DNA damage induced by PI3K inhibitors in this mutational background is a consequence of impaired production of nucleotides needed for DNA synthesis and DNA repair. Inhibition of PI3K causes a reduction in all four nucleotide triphosphates, whereas inhibition of the protein kinase AKT is less effective than inhibition of PI3K in suppressing nucleotide synthesis and inducing DNA damage. Carbon flux studies reveal that PI3K inhibition disproportionately affects the nonoxidative pentose phosphate pathway that delivers Rib-5-phosphate required for base ribosylation. In vivo in a mouse model of BRCA1-linked triple-negative breast cancer (K14-Cre BRCA1(f/f)p53(f/f)), the PI3K inhibitor BKM120 led to a precipitous drop in DNA synthesis within 8 h of drug treatment, whereas DNA synthesis in normal tissues was less affected. In this mouse model, combined PI3K and PARP inhibition was superior to either agent alone to induce durable remissions of established tumors.

Topics: Aminopyridines; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cell Proliferation; DNA Damage; DNA, Neoplasm; Female; Humans; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Morpholines; Nucleosides; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Poly(ADP-ribose) Polymerase Inhibitors; Triple Negative Breast Neoplasms

To explore the molecular mechanisms of resistance to phosphatidyl inositol 3-kinase (PI3K) inhibitors in triple-negative breast cancer (TNBC) cells.. HCC70 cells (TNBC) were transfected with siFZD7, siWANT5B or siGSK3 using lipofectamine 2000 transfection reagent. The expression levels of key proteins of WNT/β-catenin and PI3K/AKT/mTOR pathways were determined by Western blot analysis. After HCC70, MCF-7 (ER-positive) and SK-BR3 (HER2-positive) cells were treated with PI3K/AKT/mTOR inhibitors, the inhibition rates of cell proliferation were measured by MTT assay, and half maximal inhibitory concentrations (IC50) were calculated. The altered activities of WNT/β-catenin and PI3K/AKT/mTOR proteins were detected by Western blot and luciferase report gene assay, respectively. The nuclear translocation of β-catenin protein was examined by immunofluorescence assay. Xenograft nude mouse model was used to evaluate the tumorigenicity of breast cancer cells treated with BKM120 in vivo. The expression levels of p-LRP6, p-4EBP1 and β-catenin proteins in the tumor tissues were determined by immunohistochemical staining.. The expression levels of FZD7, WANT5B and GSK3 proteins were significantly reduced in the HCC70 cells transfected with the target siRNAs. Meanwhile, the activity of WNT/β-catenin was enhanced and PI3K/AKT/mTOR pathway was inhibited. PI3K/AKT/mTOR inhibitors suppressed MCF-7 and SK-BR3 cell proliferation. The IC50 of GDC-094, BKM120, XL147, perifosine, everolimus, and BEZ235 in MCF-7 cells were 0.46 mmol/L, 1.44 mmol/L, 4.34 mmol/L, 11.35 μmol/L, 53.71 μmol/L and 12.87 μmol/L respectively, and 0.63 mmol/L, 0.58 mmol/L, 3.74 mmol/L, 13.22 μmol/L, 60.00 μmol/L and 11.38 μmol/L in the SK-BR3 cells, respectively. The results of luciferase report gene assay showed that the luciferase activities in HCC70, MCF-7 and SK-BR3 cells treated with BKM120 were 1.75±0.05, 1.13±0.02 and 0.43±0.01, respectively. The luciferase activities in HCC70 and SK-BR3 cells were significantly different from that of the control cells (1.00±0.02, P<0.05). The immunohistochemical analysis showed that BKM120 inhibited mTOR activity, and the enhanced WNT/β-catenin activity reversed the phenotype of inhibitory mTOR induced by BKM120. BKM120 suppressed the tumorigenic ability of MCF-7 and SK-BR3 cells in vivo, but had no effect on cultured HCC70 cells. The immunohistochemical analysis showed nuclear translocation of β-catenin protein and increased expression level of p-LRP-6 protein in transplanted tumor tissues from HCC70 cells treated with BKM120, increased the level of p-LRP-6 protein, and no changes of p-4EBP1 protein expression. However, no nuclear translocation of β-catenin protein and no decrease of p-LRP6 and p-4EBP1 protein levels in the transplanted tumor tissue of MCF-7 cells after treatment with BKM120.. The triple-negative breast cancer HCC70 cells have drugs-resistance to PI3K inhibitors. The WNT/β-catenin signaling pathway may regulate the PI3K/AKT/mTOR pathway, therefore, inducing the drug-resistance of TNBC cells to PI3K inhibitors.

Topics: Adaptor Proteins, Signal Transducing; Aminopyridines; Animals; beta Catenin; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Humans; Imidazoles; Mice; Morpholines; Phosphatidylinositol 3-Kinase; Phosphatidylinositol 3-Kinases; Phosphoproteins; Proto-Oncogene Proteins c-akt; Quinolines; Signal Transduction; TOR Serine-Threonine Kinases; Triple Negative Breast Neoplasms

The polycomb protein MEL-18 has been proposed as a tumor suppressor in breast cancer; however, its functional relevance to the hormonal regulation of breast cancer remains unknown. Here, we demonstrated that MEL-18 loss contributes to the hormone-independent phenotype of breast cancer by modulating hormone receptor expression. In multiple breast cancer cohorts, MEL-18 was markedly downregulated in triple-negative breast cancer (TNBC). MEL-18 expression positively correlated with the expression of luminal markers, including estrogen receptor-α (ER-α, encoded by ESR1). MEL-18 loss was also associated with poor response to antihormonal therapy in ER-α-positive breast cancer. Furthermore, whereas MEL-18 loss in luminal breast cancer cells resulted in the downregulation of expression and activity of ER-α and the progesterone receptor (PR), MEL-18 overexpression restored ER-α expression in TNBC. Consistently, in vivo xenograft experiments demonstrated that MEL-18 loss induces estrogen-independent growth and tamoxifen resistance in luminal breast cancer, and that MEL-18 overexpression confers tamoxifen sensitivity in TNBC. MEL-18 suppressed SUMOylation of the ESR1 transactivators p53 and SP1, thereby driving ESR1 transcription. MEL-18 facilitated the deSUMOylation process by inhibiting BMI-1/RING1B-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). These findings demonstrate that MEL-18 is a SUMO-dependent regulator of hormone receptors and suggest MEL-18 expression as a marker for determining the antihormonal therapy response in patients with breast cancer.

Topics: Aminopyridines; Animals; Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Breast Neoplasms; Carcinoma, Ductal, Breast; Cysteine Endopeptidases; Drug Resistance, Neoplasm; Endopeptidases; Estrogen Receptor alpha; Estrogens; Female; Humans; Kaplan-Meier Estimate; Mice; Morpholines; Neoplasm Proteins; Neoplasm Transplantation; Neoplasms, Hormone-Dependent; Polycomb Repressive Complex 1; Progesterone; Proportional Hazards Models; Proteasome Endopeptidase Complex; Protein Processing, Post-Translational; Receptor, ErbB-2; Receptors, Progesterone; RNA, Messenger; RNA, Neoplasm; Sp1 Transcription Factor; Sumoylation; Tamoxifen; Triple Negative Breast Neoplasms; Tumor Suppressor Protein p53

To investigatethe effect of NVP-BKM120 on the triple-negative breast cancer cell lines.. Breast cancer cell line MDA-MB-231 and Cal51 were divided into control group and experimental group. The inhibitory effects of BKM120 were evaluated by MTT assays. The drug effects on CSC population and characteristics were investigated through mammosphere formation assay and colony formation assay. Western blot was used to observe the expressionof related protein. The BALB/c mice were injected with stem cells (SCs) and different treatments were administered subsequently.. In MDA-MB-231 cell lines, IC50 of BKM120 was (20.01±3.46) µmol/L for SCs and (3.07±0.14) µmol/L for total cells. BKM120 significantly inhibit the cell growth, in vitrocloning and microspheres formed of triple-negative breast cancer cells. BKM120 can inhibit tumor growth in nude mice without significant adverse reactions.. BKM120 can significantly inhibit the proliferation of the triple-negative breast cancer cell lines.

Topics: Aminopyridines; Animals; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Mice; Mice, Inbred BALB C; Mice, Nude; Morpholines; Triple Negative Breast Neoplasms