Abstract New efforts are being focused on signalling pathways as targets for cancer therapy. This particular study was designed to investigate whether blockade of the phosphatidylinositol 3OH‐kinase (PI3K) pathway (a survival/anti‐apoptosis pathway, overexpressed in various tumours) could sensitise human breast cancer cells to the effect of chemotherapeutics. Doxorubicin (Dox) and LY294002 (LY, a PI3K inhibitor) were used individually or in combination on MDA‐MB‐231 ( p53 mutant, ER‐), T47D ( p53 mutant, ER+), and MCF‐7 ( p53 wildtype, ER+) human breast cancer cell lines, and on 184A1, a nonmalignant human breast epithelial cell line ( p53 wildtype, ER‐). Each drug showed time‐ and dose‐dependent growth inhibition of cell proliferation on all 4 cell lines. The combination of Dox+LY resulted in enhanced cell growth inhibition in MDA‐MB‐231 and T47D cells, and additive inhibition in MCF‐7 and 184A1 cells. Cell cycle analysis showed that Dox+LY enhanced the arrest of MDA‐MB‐231 and T47D cells in G2 with the appearance of a sub‐G1 peak indicating apoptosis/necrosis, a notion supported by enhanced depolarisation of mitochondrial membrane potential in these cell types. The combination also caused a greater additive increase in Cyclin B1. Thus, the synergistic effect of the combination on cell proliferation in some, but not all, breast cancer cells may be through enhanced induction of both G2 arrest and apoptosis, in which p53 may play a role. Substantially lower doses of doxorubicin could be used with low doses of inhibitors of the PI3K pathway, without compromising the anti‐cancer effect, but also lowering detrimental side‐effects of doxorubicin. This study supports the notion that survival signalling pathways offer special targets for chemotherapy in cancer. © 2008 Wiley‐Liss, Inc.

LY294002

10.1002/ijc.23671

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Citations (36)

Prolactin induced tyrosine phosphorylation of p59fyn may mediate phosphatidylinositol 3-kinase activation in Nb2 cells

Journal of Molecular Endocrinology (1997)

Kaltoom Al‐Sakkaf P.R.M. Dobson B. L. Brown

Our previous studies indicated that PI3-kinase is involved in prolactin (PRL) signalling. We have now examined the involvement of the src tyrosine kinase, fyn, in PRL-induced the activation of PI3-kinase in the rat lymphoma cell line, Nb2. Cells were stimulated with increasing doses of PRL, lysed and immunoprecipitated with anti-fyn specific antibody. Then PI3-kinase activity was measured as the increase in the phosphorylation of phosphatidylinositol to phosphatidylinositol 3-phosphate separated by TLC. Our data indicated that, in PRL treated cells, co-precipitation of PI3-kinase with anti-fyn antiserum led to time and dose-dependent activation of PI3-kinase in vitro and that this activation was blocked by the addition of LY294002. However, LY294002 appeared to have no effect on fyn autophosphorylation. Furthermore, the physical association of PI3-kinase with fyn was confirmed by Western blot analysis employing the same specific antisera. These data provide evidence that PRL-induced activation of PI3-kinase may be mediated by the tyrosine phosphorylation of fyn in Nb2 cells.

FYN

10.1677/jme.0.0190347

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Citations (44)

Cytokine-induced activation of protein kinases in breast cancer cells

Cytokine (1994)

Kaltoom Al‐Sakkaf CAROLYN DAWSON Guylène Page James E. Dunford P.R.M. Dobson

10.1016/1043-4666(94)90308-5

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Differential crosstalk between the AMPK and PI3K/Akt pathways in breast cancer cells of differing genotypes: Leptin inhibits the effectiveness of AMPK activation

Oncology Reports (2015)

Omar S. El-Masry Kaltoom Al‐Sakkaf B. L. Brown Pauline R.M. Dobson

AMP-activated protein kinase (AMPK), a sensor of cellular energy, is widely reported as a potential therapeutic target in treatment of breast and other cancers. The activated enzyme has been shown to be a promising anti-proliferative agent in breast cancer cell lines. However, little data exist on crosstalk between AMPK and the cellular survival axis of PI3K/Akt/mTOR pathway and the impact of microenvironment on cellular responses to AMPK activation. We present results which show differential crosstalk between AMPK and Akt, dependent on the cellular genetics of each breast cancer cell type. We also show that leptin blocks activation of AMPK and partially or completely attenuates the anti-proliferative effect of AMPK activation depending on the cell type. This suggests that leptin within the local environment might impose limitations on therapeutic usage of AMPK activators in cancer, thereby attenuating their effective use in many obese subjects.

Crosstalk

10.3892/or.2015.4198

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Citations (26)

The Potential Role of Nigella sativa Seed Oil as Epigenetic Therapy of Cancer

Molecules (2022)

Safialdin Alsanosi Ryan A. Sheikh Sultan N. Sonbul Hisham N. Altayb Afnan S. Batubara

Nigella sativa oil, commonly known as black seed oil (BSO), is a well-known Mediterranean food, and its consumption is associated with beneficial effects on human health. A large number of BSO's therapeutic properties is attributed to its pharmacologically active compound, thymoquinone (TQ), which inhibits cell proliferation and induces apoptosis by targeting several epigenetic players, including the ubiquitin-like, containing plant homeodomain (PHD) and an interesting new gene, RING finger domains 1 (UHRF1), and its partners, DNA methyltransferase 1 (DNMT1) and histone deacetylase 1 (HDAC1). This study was designed to compare the effects of locally sourced BSO with those of pure TQ on the expression of the epigenetic complex UHRF1/DNMT1/HDAC1 and the related events in several cancer cells. The gas chromatographs obtained from GC-MS analyses of extracted BSO showed that TQ was the major volatile compound. BSO significantly inhibited the proliferation of MCF-7, HeLa and Jurkat cells in a dose-dependent manner, and it induced apoptosis in these cell lines. BSO-induced inhibitory effects were associated with a significant decrease in mRNA expression of UHRF1, DNMT1 and HDAC1. Molecular docking and MD simulation showed that TQ had good binding affinity to UHRF1 and HDAC1. Of note, TQ formed a stable metal coordinate bond with zinc tom, found in the active site of the HDAC1 protein. These findings suggest that the use of TQ-rich BSO represents a promising strategy for epigenetic therapy for both solid and blood tumors through direct targeting of the trimeric epigenetic complex UHRF1/DNMT1/ HDAC1.

DNMT1

HDAC1

Thymoquinone

DNA methyltransferase

Epigenetic Therapy

10.3390/molecules27092779

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Abstract 243: Integration of transcriptome and metabolome provides unique insights to pathways associated with obese breast cancer patients

Cancer Research (2020)

Mohammed Abdullah Hassan Kaltoom Al‐Sakkaf Mohammed Razeeth Shait Mohammed Ashraf Dallol Jaudah Al‐Maghrabi

Abstract Information regarding transcriptome and metabolome has significantly contributed to the identification of potential therapeutic targets for the management of a variety of cancers. Obesity has been shown to have profound effects on both cancer cell transcriptome and metabolome and to affect the outcome of cancer therapy. The information regarding the potential effects of obesity on breast cancer (BC) transcriptome, metabolome, and its integration to identify novel pathways related to disease progression are still elusive. We assessed the whole blood transcriptome and serum metabolome as circulating metabolites, of obese BC patients and compared them with non-obese BC patients. In these patients, 186 differentially expressed genes (DEGs) were observed, with 156 upregulated and 30 downregulated, significantly. The DEGs were enriched in different cellular pathways: cell cycle, one carbon pathway, homologous recombination cellular senescence, and notch signaling pathway. Our results confirmed the altered expression of several DEGs by quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, 96 deregulated metabolites were identified when untargeted metabolomics was performed in obese BC patients when compared to non-obese BC patients, these were enriched in 71 pathways, most of them involved in ATP generation and cell proliferation. Finally, to provide a more comprehensive understanding of the association between obesity and BC, integration analysis between transcriptome and metabolomics data at the pathway level, revealed seven enriched pathways in obese BC vs. non-obese BC patients, that includes glutathione metabolism, glycine and serine metabolism, valine, leucine, and isoleucine degradation, purine metabolism, pyrimidine metabolism, thyroid hormone synthesis, and vitamin B6 metabolism; which may provide resistance for BC cell to dodge the circulating immune cells in whole blood. In conclusion, this study provides information on the unique pathways alteration at transcriptome and metabolome levels in obese BC patients, which may become an important tool for researchers and contribute to a rise in the knowledge on the molecular interaction between obesity and BC. Further studies are needed to confirm this and to elucidate the exact underlying mechanism for the effects of obesity on the BC initiation or/and progression. Citation Format: Mohammed Abdullah Hassan, Kaltoom Al-Sakkaf, Mohammed Razeeth Shait Mohammed, Ashraf Dallol, Jaudah Al-Maghrabi, Alia Aldahlawi, Sawsan Ashoor, Mabrouka Maamra, Jiannis Ragoussis, Wei Wu, Mohammad Imran Khan, Abdulrahman Al-Malki, Hani Choudhry. Integration of transcriptome and metabolome provides unique insights to pathways associated with obese breast cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 243.

Metabolome

Pyrimidine metabolism

Metabolic pathway

10.1158/1538-7445.am2020-243

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Suppression of circulating AP001429.1 long non‑coding RNA in obese patients with breast cancer

Oncology Letters (2021)

Hani Choudhry Mohammed Hassan Abdulrahman L. Al‐Malki Kaltoom Al‐Sakkaf

Long non‑coding RNAs (lncRNAs), a type of cellular RNA, play a critical regulatory role in several physiological developments and pathological processes, such as tumorigenesis and tumor progression. Obesity is a risk factor for a number of serious health conditions, including breast cancer (BC). However, the underlying mechanisms behind the association between obesity and increased BC incidence and mortality remain unclear. Several studies have reported changes in lncRNA expression due to obesity and BC, independently encouraging further investigation of the relationship between the two in connection with lncRNAs. The present study was designed to first screen for the expression of 29 selected lncRNAs that showed a link to cancer or obesity in the blood of a selected cohort of 6 obese and 6 non‑obese patients with BC. The expression levels of significantly expressed lncRNAs, AP001429.1, PCAT6, P5549, P19461 and P3134, were further investigated in a larger cohort of 69 patients with BC (36 obese and 33 non‑obese), using reverse transcription‑quantitative polymerase chain reaction. Results showed not only that AP001429.1 remained significantly downregulated in the larger cohort (P=0.002), but also that it was associated with several clinicopathological characteristics, such as negative HER2 status, negative E‑cadherin expression, negative vascular invasion, negative margin invasion and LCIS. These findings suggest that obesity may have a role in inhibiting AP001429.1 expression, which may serve as a novel potential biomarker and therapeutic target for BC.

10.3892/ol.2021.12769

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Apoptotic mechanisms in T47D and MCF-7 human breast cancer cells

British Journal of Cancer (2002)

Laura Mooney Kaltoom Al‐Sakkaf B. L. Brown Pauline R.M. Dobson

To investigate the mechanisms underlying apoptosis in breast cancer cells, staurosporine was used as an apoptotic stimulus in the human breast cancer cell lines MCF-7 and T47D. Staurosporine induced dose and time dependent increases in DNA fragmentation which was abrogated by z-VAD-fmk. MCF-7 cells did not express caspase-3, suggesting that DNA fragmentation occurred in the absence of caspase-3 and that other caspases may be involved. Staurosporine induced DEVDase activity in T47D cells suggesting the involvement of caspase-3 and/or caspase-7, yet there was no DEVDase activity in MCF-7 cells, probably ruling out the involvement caspase-7. However, staurosporine induced the cleavage of pro-caspase-6 in MCF-7 cells, but not in T47D cells. Caspase dependent PARP cleavage was detected in MCF-7 cells at 3 h, whereas only partial PARP cleavage was detected in T47D cells and then only after 24 h. Moreover, staurosporine led to cytochrome c release at 2 h in MCF-7 cells and 6 h in T47D cells. In addition, a time dependent and caspase-independent reduction of the mitochondrial transmembrane potential was observed; which appeared to occur after the release of cytochrome c. Translocation of Bax from the cytosol to mitochondria was observed in both cell types, and this preceded cytochrome c release in both T47D and MCF-7 cells. Apoptotic events in both cell types differ temporally, involving activation of different caspases and mitochondrial changes.

Staurosporine

MCF-7

Caspase 7

10.1038/sj.bjc.6600541

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Citations (184)

Herpesvirus entry mediator as a potential biomarker in breast cancer compared with conventional cytotoxic T‑lymphocyte‑associated antigen 4

Biomedical Reports (2023)

Alia Aldahlawi Fatemah Basingab Jehan Alrahimi Kawther Zaher Peter Natesan Pushparaj

Breast cancer (BC) is the most common cancer in women worldwide, with 2.3 million cases recorded in 2020. Despite improvements in cancer treatment, patients with BC still succumb to the disease, due to regional and distant metastases when diagnosed at later stages. Several immune checkpoint inhibitors have been approved for BC treatment, based on their expression and role in maintaining immunosurveillance against tumors. The present study aimed to evaluate the expression of 12 immune checkpoints in patients with BC, and assess their role as diagnostic and therapeutic markers. Expression levels were measured using reverse transcription‑quantitative polymerase chain reaction. Among the 12 immune markers, herpesvirus entry mediator (HVEM) was found to be significantly upregulated in patients with malignant BC compared to non‑malignant controls, with a relative fold change (FC) of 1.46 and P=0.012. A similar finding was observed for cytotoxic T‑lymphocyte‑associated antigen 4 (CTLA4; FC=1.47 and P=0.035). In addition, receiver operating characteristic curve analysis revealed that HVEM expression allowed significant differentiation between groups, with an area under the curve of 0.74 (P=0.013). Upregulation in both HVEM and CTLA4 was revealed to be significantly associated with the human epidermal growth factor receptor‑2 (HER2)‑enriched phenotype (FC=3.53, P=0.009 and FC=5.98, P=0.002, respectively), while only HVEM was significantly associated with the triple‑negative phenotype (FC=2.07, P=0.016). Furthermore, HVEM was significantly higher in patients with grade III tumors (FC=1.88, P=0.025) and negative vascular invasion (FC=1.67, P=0.046) compared with non‑malignant controls. Serum protein levels were assessed by multiplex immunoassay, and a significant increase in HVEM was detected in patients with malignant BC compared with that in non‑malignant controls (P=0.035). These data indicated that HVEM may serve as a potential biomarker and target for immunotherapy, especially for certain types of BC.

Immunosurveillance

10.3892/br.2023.1638

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Citations (2)