Purpose: The constitutive activation of STAT3 through receptor tyrosine kinases triggered breast cancer cell growth, and invasion-metastasis. Atiprimod impacts anti-proliferative, anti-carcinogenic effects in hepatocellular carcinoma, lymphoma, multiple myeloma via hindering the biological activity of STAT3. Dose-dependent atiprimod evokes rst autophagy as a survival mechanism and then apoptosis due to prolonged ER stress in pituitary adenoma cells. The therapeutic e ciency and mechanistic action of atiprimod in breast cancer cells have not been investigated yet. Thus, we aimed to modulate the pivotal role of ER stress in atiprimod-triggered apoptosis in MDA-MB-231 and MDA-MB-468 breast cancer cells.Results: Dose-and time-dependent atiprimod treatment inhibits cell viability and colony formation in MDA-MB-468 and MDA-MB-231 breast cancer cells. A moderate dose of atiprimod (2 mM) inhibited STAT3 phosphorylation at Tyr705 residue and also suppressed the total expression level of p65. In addition, nuclear localization of STAT1, 3 and NF-kB was prevented by atiprimod exposure in MDA-MB-231 and MDA-MB-468 cells. Atiprimod evokes PERK, BiP, ATF-4, CHOP upregulation, and PERK (Thr980), eIF2a (Ser51) phosphorylation's. However, atiprimod suppressed IRE1a-mediated Atg-3, 5, 7, 12 protein expressions and no alteration were observed on Beclin-1, p62 expression levels. PERK/eIF2a/ATF4/CHOP axis pivotal role in atiprimod-mediated G1/S arrest and apoptosis via Bak, Bax, Bim and PUMA upregulation in MDA-MB-468 cells. Moreover, atiprimod renders MDA-MB-231 more vulnerable to type I programmed cell death by plasmid-mediated increased STAT3 expression. Conclusion:Atiprimod induced prolonged ER stress-mediated apoptosis via both activating PERK/eIF2a/ATF4/CHOP axis and suppressing STAT3/NF-kB transcription factors nuclear migration in TBNC cells. HighlightsAtiprimod induced endoplasmic reticulum stress

Aptamers are small and specific oligonucleotides [RNA or single-strand DNA (ssDNA)] with a high binding affinity against target protein. In vitro selection process of aptamer by selective evolution of ligands by exponential enrichment (SELEX) has been invented in 1990 by Larry Gold and Jack Szostak. SELEX is a random amplification of target protein with combined oligonucleotide libraries and selection of synthesized aptamer by magnetic beads, affinity chromatography, and capillary electrophoresisbased methods. According to their low molecular weight, non-immunogenic feature in vivo, low production cost, high thermal stability, increase in production potential, and ample of modification capacities, aptamers are becoming essential medical tools for diagnosis and treatment of diseases such as macular degeneration, hemophilia, heart disease, and various cancer types. The therapeutic potential of aptamers, with high binding affinity against carcinogenesis-associated growth factors, receptors, or proteins frequently overexpressed in specific cancers such as prostate, breast, colon, lung, leukemia, hepatocellular, and cervical carcinoma. The strategies for aptamerbased drugs in cancer therapy design/modify aptamers against cancer biomarkers, accelerate immunotherapy targeting immune system, and increase the drug delivery in cancer cells. In conclusion, aptamers are promising candidate drugs due to their antiproliferative effect on cancer cells and the drug delivery systems during cancer chemotherapy.

Background Growth Hormone Releasing Hormone (GHRH), 44 amino acids containing hypothalamic hormone, retains the biological activity by its first 29 amino acids. GHRH (NH2 1–29) peptide antagonists inhibit the growth of prostate, breast, ovarian, renal, gastric, pancreatic cancer in vitro and in vivo. Aptamers, single-strand RNA, or DNA oligonucleotides are capable of binding to target molecules with high affinity. Our aim in this study is to synthesize and select X-aptamers against both GHRH NH2 (1–29) and GHRH NH2 (1–44) and demonstrate synthesized aptamers’ target binding activity as well as serum stability. Methods and results Aptamers against GHRH NH2 (1–44) and NH2 (1–29) peptides were synthesized, and binding affinity (Kd) of 24 putative X-aptamers was determined by the dot-blot method, co-immunofluorescence staining and, SPR analysis. The serum stability of TKY.T1.08, TKY1.T1.13, TKY.T2.08, TKY.T2.09 X-aptamers was 90–120 h, respectively. The dose-dependent binding of TKY1.T1.13, TKY.T2.08, TKY.T2.09 X-aptamers on GHRHR in MIA PaCa-2 was approved by co-IF assay results. Moreover, SPR analysis indicated the Kd (4.75, 1.21, and 4.0 nM) levels of TKY2.T1.13, TKY.T2.08, TKY.T2.09 putative X-aptamers, respectively. Conclusion Our results illustrate the synthesis of 24 putative X-aptamers against both GHRH NH2 (1–44) and NH2 (1–29) peptides and TKY1.T1.13, TKY.T2.08, TKY.T2.09 X-aptamers have high serum stability, high target binding potential with low Kd levels.

Purpose: The constitutive activation of STAT3 through receptor tyrosine kinases triggered breast cancer cell growth, and invasion-metastasis. Atiprimod impacts anti-proliferative, anti-carcinogenic effects in hepatocellular carcinoma, lymphoma, multiple myeloma via hindering the biological activity of STAT3. Dose-dependent atiprimod evokes first autophagy as a survival mechanism and then apoptosis due to prolonged ER stress in pituitary adenoma cells. The therapeutic efficiency and mechanistic action of atiprimod in breast cancer cells have not been investigated yet. Thus, we aimed to modulate the pivotal role of ER stress in atiprimod-triggered apoptosis in MDA-MB-231 and MDA-MB-468 breast cancer cells. Results: Dose- and time-dependent atiprimod treatment inhibits cell viability and colony formation in MDA-MB-468 and MDA-MB-231 breast cancer cells. A moderate dose of atiprimod (2 mM) inhibited STAT3 phosphorylation at Tyr705 residue and also suppressed the total expression level of p65. In addition, nuclear localization of STAT1, 3 and NF-kB was prevented by atiprimod exposure in MDA-MB-231 and MDA-MB-468 cells. Atiprimod evokes PERK, BiP, ATF-4, CHOP upregulation, and PERK (Thr980), eIF2a (Ser51) phosphorylation’s. However, atiprimod suppressed IRE1a-mediated Atg-3, 5, 7, 12 protein expressions and no alteration were observed on Beclin-1, p62 expression levels. PERK/eIF2a/ATF4/CHOP axis pivotal role in atiprimod-mediated G1/S arrest and apoptosis via Bak, Bax, Bim and PUMA upregulation in MDA-MB-468 cells. Moreover, atiprimod renders MDA-MB-231 more vulnerable to type I programmed cell death by plasmid-mediated increased STAT3 expression. Conclusion: Atiprimod induced prolonged ER stress-mediated apoptosis via both activating PERK/eIF2a/ATF4/CHOP axis and suppressing STAT3/NF-kB transcription factors nuclear migration in TBNC cells.