Improved cellular automata model shows that indirect apoptotic cell death due to vascular damage enhances the local control of tumors by single fraction high-dose irradiation

Author(s):  
Daisuke Kawahara ◽  
Yasushi Nagata ◽  
Yoichi Watanabe

Abstract We investigated the effects of indirect apoptotic cell death due to vascular damage on tumor response to a single large dose with an improved two-dimensional cellular automata model. The tumor growth was simulated by considering the oxygen and nutrients supplied to the tumor through the blood vessels. The cell damage processes were modeled by taking account of the direct cell death and the indirect death due to the radiation-induced vascular damages. The radiation increased the permeation of oxygen and nutrients through the blood vessel or caused the breakdown of the vasculature. The amount of oxygen in cancer cells affected the response of cancer cells to radiation and the tumor growth rate after irradiation. The lack of oxygen led to the apoptotic death of cancer cells. We calculated the tumor control probability (TCP) at different radiation doses, D, the probability of apoptotic death, PO2_ap, the threshold of the oxygen level for indirect apoptotic death, O2t, the average oxygen level in cancer cells, [O2]av, and the vessel survival probability after radiation damage, Pv. Due to the vessel damage, indirect cell death led to a 4% increase in TCP for the dose ranging from 15 Gy to 20 Gy. TCP increased with increasing PO2_ap and O2t due to increased apoptotic death. The variation of TCP as a function of [O2]av exhibited the minimum at [O2]av of 2.7%. The apoptosis increased as [O2]av decreased, leading to an increasing TCP. On the other hand, the direct radiation damage increased, and the apoptosis decreased for higher [O2]av, resulting in a higher TCP. We showed by modeling the radiation damage of blood vessels in a 2D CA simulation that the indirect apoptotic death of cancer cells, caused by the reduction of the oxygen level due to vascular damage after high dose irradiation, increased TCP.

2013 ◽  
Vol 3 (3) ◽  
pp. 66 ◽  
Author(s):  
Vanessa Hörmann ◽  
Sivanesan Dhandayuthapani ◽  
James Kumi-Diaka ◽  
Appu Rathinavelu

Background: Prostate cancer is the second most common cancer in American men. The development of alternative preventative and/or treatment options utilizing a combination of phytochemicals and chemotherapeutic drugs could be an attractive alternative compared to conventional carcinoma treatments. Genistein isoflavone is the primary dietary phytochemical found in soy and has demonstrated anti-tumor activities in LNCaP prostate cancer cells. Topotecan Hydrochloride (Hycamtin) is an FDA-approved chemotherapy for secondary treatment of lung, ovarian and cervical cancers. The purpose of this study was to detail the potential activation of the intrinsic apoptotic pathway in LNCaP prostate cancer cells through genistein-topotecan combination treatments. Methods: LNCaP cells were cultured in complete RPMI medium in a monolayer (70-80% confluency) at 37ºC and 5% CO2. Treatment consisted of single and combination groups of genistein and topotecan for 24 hours. The treated cells were assayed for i) growth inhibition through trypan blue exclusion assay and microphotography, ii) classification of cellular death through acridine/ ethidium bromide fluorescent staining, and iii) activation of the intrinsic apoptotic pathway through Jc-1: mitochondrial membrane potential assay, cytochrome c release and Bcl-2 protein expression.Results: The overall data indicated that genistein-topotecan combination was significantly more efficacious in reducing the prostate carcinoma’s viability compared to the single treatment options. In all treatment groups, cell death occurred primarily through the activation of the intrinsic apoptotic pathway.Conclusion: The combination of topotecan and genistein has the potential to lead to treatment options with equal therapeutic efficiency as traditional chemo- and radiation therapies, but lower cell cytotoxicity and fewer side effects in patients. Key words: topotecan; genistein; intrinsic apoptotic cell death


Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2004
Author(s):  
Prabhu Thirusangu ◽  
Christopher L. Pathoulas ◽  
Upasana Ray ◽  
Yinan Xiao ◽  
Julie Staub ◽  
...  

We previously reported that the antimalarial compound quinacrine (QC) induces autophagy in ovarian cancer cells. In the current study, we uncovered that QC significantly upregulates cathepsin L (CTSL) but not cathepsin B and D levels, implicating the specific role of CTSL in promoting QC-induced autophagic flux and apoptotic cell death in OC cells. Using a Magic Red® cathepsin L activity assay and LysoTracker red, we discerned that QC-induced CTSL activation promotes lysosomal membrane permeability (LMP) resulting in the release of active CTSL into the cytosol to promote apoptotic cell death. We found that QC-induced LMP and CTSL activation promotes Bid cleavage, mitochondrial outer membrane permeabilization (MOMP), and mitochondrial cytochrome-c release. Genetic (shRNA) and pharmacological (Z-FY(tBU)-DMK) inhibition of CTSL markedly reduces QC-induced autophagy, LMP, MOMP, apoptosis, and cell death; whereas induced overexpression of CTSL in ovarian cancer cell lines has an opposite effect. Using recombinant CTSL, we identified p62/SQSTM1 as a novel substrate of CTSL, suggesting that CTSL promotes QC-induced autophagic flux. CTSL activation is specific to QC-induced autophagy since no CTSL activation is seen in ATG5 knockout cells or with the anti-malarial autophagy-inhibiting drug chloroquine. Importantly, we showed that upregulation of CTSL in QC-treated HeyA8MDR xenografts corresponds with attenuation of p62, upregulation of LC3BII, cytochrome-c, tBid, cleaved PARP, and caspase3. Taken together, the data suggest that QC-induced autophagy and CTSL upregulation promote a positive feedback loop leading to excessive autophagic flux, LMP, and MOMP to promote QC-induced cell death in ovarian cancer cells.


2015 ◽  
Vol 59 (2) ◽  
pp. 178-189 ◽  
Author(s):  
Raquel Ordoñez ◽  
Anna Fernández ◽  
Néstor Prieto-Domínguez ◽  
Laura Martínez ◽  
Carmen García-Ruiz ◽  
...  

APOPTOSIS ◽  
2009 ◽  
Vol 14 (7) ◽  
pp. 913-922 ◽  
Author(s):  
A-Mi Seo ◽  
Seung-Woo Hong ◽  
Jae-Sik Shin ◽  
In-Chul Park ◽  
Nam-Joo Hong ◽  
...  

Molecules ◽  
2018 ◽  
Vol 23 (3) ◽  
pp. 621 ◽  
Author(s):  
Jeong-Hyeon Ko ◽  
Seok-Geun Lee ◽  
Woong Yang ◽  
Jae-Young Um ◽  
Gautam Sethi ◽  
...  

Embelin is a naturally-occurring benzoquinone compound that has been shown to possess many biological properties relevant to human cancer prevention and treatment, and increasing evidence indicates that embelin may modulate various characteristic hallmarks of tumor cells. This review summarizes the information related to the various oncogenic pathways that mediate embelin-induced cell death in multiple cancer cells. The mechanisms of the action of embelin are numerous, and most of them induce apoptotic cell death that may be intrinsic or extrinsic, and modulate the NF-κB, p53, PI3K/AKT, and STAT3 signaling pathways. Embelin also induces autophagy in cancer cells; however, these autophagic cell-death mechanisms of embelin have been less reported than the apoptotic ones. Recently, several autophagy-inducing agents have been used in the treatment of different human cancers, although they require further exploration before being transferred from the bench to the clinic. Therefore, embelin could be used as a potential agent for cancer therapy.


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