scholarly journals Molecular Mechanisms of Antitumor Activity of PAMAM Dendrimer Conjugates with Anticancer Drugs and a Monoclonal Antibody

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1422 ◽  
Author(s):  
Marcinkowska ◽  
Stanczyk ◽  
Janaszewska ◽  
Gajek ◽  
Ksiezak ◽  
...  

Taxanes are considered fundamental drugs in the treatment of breast cancer, but despite the similarities, docetaxel (doc) and paclitaxel (ptx) work differently. For this reason, it is interesting to identify mechanisms of antitumor activity of PAMAM dendrimer conjugates that carry docetaxel or paclitaxel and monoclonal antibody trastuzumab, specifically targeted to cells which overexpressed HER-2. For this purpose, the impact on the level of reactive oxygen species, the mitochondrial membrane potential, cell cycle distribution and the activity of caspases-3/7, -8 and -9 of PAMAM-doc-trastuzumab and PAMAM-ptx-trastuzumab conjugates was determined and compared with free docetaxel and paclitaxel toward HER-2-positive (SKBR-3) and negative (MCF-7) human breast cancer cell lines. Moreover, apoptosis and necrosis were studied using flow cytometry and confocal microscopy, respectively. Our studies show the complexity of the potential mechanism of cytotoxic action of PAMAM-drug-trastuzumab conjugates that should be sought as a resultant of oxidative stress, mitochondrial activation of the caspase cascade and the HER-2 receptor blockade.

2020 ◽  
Author(s):  
Changran Wei ◽  
Xiangqi Li

Abstract Background Breast cancer (BC) can be separated into four molecular subclassifications including Lumina1 A, Lumina1 B, HER-2 overexpression and Basal-like subtype. These classifications are based on estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2) and cell proliferation antigen (Ki-67). The Hippo signaling pathway plays an indispensable role in BC. The YAP1 gene is a terminal effector of Hippo pathway, and hyperactivation of YAP mediates tumorigenesis. As an inhibitor of YAP, non-photoactivated verteporfin (VP) can inhibit YAP-mediated tumor proliferation and angiogenesis by eliminating its interaction with TEAD. This study set out to determine the effect and molecular mechanisms of VP-mediated inhibition of YAP in different subtypes of BC. Methods Luminal A, Luminal B and Basal-like BC cells were cultivated in vitro in order to study effect of VP on proliferation and apoptosis on these three molecular BC subtypes. Results Our experimental results show that VP inhibits cell proliferation, YAP-TEAD interaction and its downstream target expression. VP also induces tumor cell apoptosis, and promotes the cleavage of Caspase-9 and PARP in various molecular subtypes of BC cells. Conclusion These findings provide a basis for VP as a potential anti-tumor therapeutic for BC by targeting the Hippo pathway effector YAP.


Author(s):  
Qiao Li ◽  
Manran Liu ◽  
Yan Sun ◽  
Ting Jin ◽  
Pengpeng Zhu ◽  
...  

Abstract Background Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, with poor prognosis and limited treatment options. Hypoxia is a key hallmark of TNBC. Metabolic adaptation promotes progression of TNBC cells that are located within the hypoxic tumor regions. However, it is not well understood regarding the precise molecular mechanisms underlying the regulation of metabolic adaptions by hypoxia. Methods RNA sequencing was performed to analyze the gene expression profiles in MDA-MB-231 cell line (20% O2 and 1% O2). Expressions of Slc6a8, which encodes the creatine transporter protein, were detected in breast cancer cells and tissues by quantitative real-time PCR. Immunohistochemistry was performed to detect SLC6A8 protein abundances in tumor tissues. Clinicopathologic correlation and overall survival were evaluated by chi-square test and Kaplan-Meier analysis, respectively. Cell viability assay and flow cytometry analysis with Annexin V/PI double staining were performed to investigate the impact of SLC6A8-mediated uptake of creatine on viability of hypoxic TNBC cells. TNBC orthotopic mouse model was used to evaluate the effects of creatine in vivo. Results SLC6A8 was aberrantly upregulated in TNBC cells in hypoxia. SLC6A8 was drastically overexpressed in TNBC tissues and its level was tightly associated with advanced TNM stage, higher histological grade and worse overall survival of TNBC patients. We found that SLC6A8 was transcriptionally upregulated by p65/NF-κB and mediated accumulation of intracellular creatine in hypoxia. SLC6A8-mediated accumulation of creatine promoted survival and suppressed apoptosis via maintaining redox homeostasis in hypoxic TNBC cells. Furthermore, creatine was required to facilitate tumor growth in xenograft mouse models. Mechanistically, intracellular creatine bolstered cell antioxidant defense by reducing mitochondrial activity and oxygen consumption rates to reduce accumulation of intracellular reactive oxygen species, ultimately activating AKT-ERK signaling, the activation of which protected the viability of hypoxic TNBC cells via mediating the upregulation of Ki-67 and Bcl-2, and the downregulation of Bax and cleaved Caspase-3. Conclusions Our study indicates that SLC6A8-mediated creatine accumulation plays an important role in promoting TNBC progression, and may provide a potential therapeutic strategy option for treatment of SLC6A8 high expressed TNBC.


2021 ◽  
Vol 22 (9) ◽  
pp. 4655
Author(s):  
Priyanka Bapat ◽  
Debalina Goswami Sewell ◽  
Mallory Boylan ◽  
Arun K. Sharma ◽  
Julian E. Spallholz

Her/2+ breast cancer accounts for ~25% mortality in women and overexpression of Her/2 leads to cell growth and tumor progression. Trastuzumab (Tz) with Taxane is the preferred treatment for Her/2+ patients. However, Tz responsive patients often develop resistance to Tz treatment. Herein, redox selenides (RSe-) were covalently linked to Tz using a selenium (Se)-modified Bolton–Hunter Reagent forming Seleno-Trastuzumab (Se-Tz; ~25 µgSe/mg). Se-Tz was compared to Tz and sodium selenite to assess the viability of JIMT-1 and BT-474 cells. Comparative cell viability was examined by microscopy and assessed by fluorometric/enzymatic assays. Se-Tz and selenite redox cycle producing superoxide (O2•−) are more cytotoxic to Tz resistant JIMT-1 and Tz sensitive BT-474 cells than Tz. The results of conjugating redox selenides to Tz suggest a wider application of this technology to other antibodies and targeting molecules.


Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5616
Author(s):  
Eugenia Fernandez ◽  
Luis Ubillos ◽  
Nabila Elgul ◽  
María Florencia Festari ◽  
Daniel Mazal ◽  
...  

Breast cancer is a public health concern and is currently the fifth cause of mortality worldwide. Identification of different biological subtypes is essential for clinical management; therefore, the role of pathologists is essential and useful tools for immunohistochemistry diagnosis are needed. Polypeptide-GalNAc-transferases are emerging novel biomarkers related to cancer behavior and GalNAc-T13, correlated with aggressiveness in some tumors, is an interesting candidate. Few monoclonal antibodies reacting with native proteins, and not affected by fixation and paraffin embedding, have been reported. The aim of this work was to develop a useful monoclonal antibody anti-GalNAc-T13 and to assess its potential significance in breast cancer diagnosis. We evaluated 6 human breast cancer cell lines, 338 primary breast tumors and 48 metastatic lymph nodes and looked for clinical significance correlating GalNAc-T13 expression with patients’ clinical features and survival. We found high GalNAc-T13 expression in 43.8% of the cases and observed a significant higher expression in metastatic lymph nodes, correlating with worse overall survival. We hypothesized several possible molecular mechanisms and their implications. We conclude that GalNAc-T13 may be a novel biomarker in breast cancer, useful for routine pathological diagnosis. Elucidation of molecular mechanisms related to aggressiveness should contribute to understand the role of GalNAc-T13 in breast cancer biology.


2020 ◽  
pp. 72-82
Author(s):  
Mossa Gardaneh ◽  
Zahra Nayeri ◽  
Parvin Akbari ◽  
Mahsa Gardaneh ◽  
Hasan Tahermansouri

Background: We investigated molecular mechanisms behind astaxanthinmediated induction of apoptosis in breast cancer cell lines toward combination therapy against cancer drug resistance. Methods: Breast cancer cell lines were treated with serial concentrations of astaxanthin to determine its IC50. We used drug-design software to predict interactions between astaxanthin and receptor tyrosine kinases or other key gene products involved in intracellular signaling pathways. Changes in gene expression were examined using RT-PCR. The effect of astaxanthin-nanocarbons combinations on cancer cells was also evaluated. Results: Astaxanthin induced cell death in all three breast cancer cell lines was examined so that its IC50 in two HER2-amplifying lines SKBR3 and BT-474 stood, respectively, at 36 and 37 ?M; however, this figure for MCF-7 was significantly lowered to 23 ?M (P<0.05). Astaxanthin-treated SKBR3 cells showed apoptotic death upon co-staining. Our in silico examinations showed that some growth-promoting molecules are strongly bound by astaxanthin via their specific amino acid residues with their binding energy standing below -6 KCa/Mol. Next, astaxanthin was combined with either graphene oxide or carboxylated multi-walled carbon nanotube, with the latter affecting SKBR cell survival more extensively than the former (P<0.05). Finally, astaxanthin coinduced tumor suppressors p53 and PTEN but downregulated the expression of growth-inducing genes in treated cells. Conclusion: These findings indicate astaxanthin carries' multitarget antitumorigenic capacities and introduce the compound as a suitable candidate for combination therapy regimens against cancer growth and drug resistance. Development of animal models to elucidate interactions between the compound and tumor microenvironment could be a major step forward towards the inclusion of astaxanthin in cancer therapy trials.


2021 ◽  
Vol 23 (1) ◽  
pp. 88-92
Author(s):  
Inna P. Ganshina ◽  
Kristina A. Ivanova ◽  
Olga O. Gordeeva ◽  
Aleksandr V. Arkhipov ◽  
Liudmila G. Zhukova

Triple-negative breast cancer is 1024% of all cases of breast cancer and is characterized by the absence of estrogen, progesterone, and HER-2 receptors in the tumor. The therapy of this illness is a difficult clinical case. In contrast to hormone-positive and HER-2-positive phenotypes, in which we successfully use targeted drugs (antiestrogens and anti-HER-2 drugs), for triple-negative breast cancer we have not had such targets for a long time. Thus, despite the impressive results of immunotherapy of triple-negative breast cancer, there remains a fairly large group of patients with negative PD-L1 status, for whom it is necessary to develop other treatment strategies. One of the approaches in the treatment of malignant tumors includes not the impact on tumor cells, but the process of angiogenesis. Antiangiogenic drugs have positively proven themselves in the treatment of a large number of malignant tumors but are underestimated for breast cancer (including triple-negative phenotype). The use of bevacizumab in combinations with cytostatic drugs in breast cancer therapy (including triple-negative breast cancer) has been studied in a large number of clinical trials but was undeservedly forgotten in some countries due to the revoked FDA registration. This review presents the role of bevacizumab in the treatment of patients with triple-negative breast cancer and suggests the conditions when the administration of this drug is justified and leads to better results.


Author(s):  
Mengyao Xu ◽  
Shan Huang ◽  
Xiaoli Dong ◽  
Yanan Chen ◽  
Miao Li ◽  
...  

Abstract Metastases are the main cause of cancer-related mortality in breast cancer. Although significant progress has been made in the field of tumor metastasis, the exact molecular mechanisms involved in tumor metastasis are still unclear. Here, we report that ATOH8-V1, a novel isoform of ATOH8, is highly expressed in breast cancer and is a negative prognostic indicator of survival for patients. Forced expression of ATOH8-V1 dramatically enhances, while silencing of ATOH8-V1 decreases the metastasis of breast cancer cell lines. Moreover, ATOH8-V1 directly binds to the RhoC promoter and stimulates the expression of RhoC, which in turn enhances the metastasis of breast cancer. Altogether, our data demonstrate that ATOH8-V1 is a novel pro-metastatic factor that enhances cancer metastasis, suggesting that ATOH8-V1 is a potential therapeutic target for treatment of metastatic cancers.


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