How to control ATP concentration in HeLa cell

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To control ATP concentration in HeLa cells, various strategies have been employed, targeting different aspects of cellular metabolism and function. One approach involves the use of synthetic ATP-binding proteins, such as DX, which is designed to reduce bioavailable ATP by targeting the mitochondria (Luo et al., 2014). DX expression in HeLa cells led to a significant reduction in cell viability and an increase in apoptosis, correlating with decreased ATP levels (Khav et al., 2016; Luo et al., 2014). Another method is the inhibition of specific proteins involved in ATP production. For instance, BIIB021, an orally available HSP90 inhibitor, has been shown to decrease ATP hydrolysis rate of HSP90, leading to cytotoxic effects on HeLa cell proliferation (Güven & Özgür, 2023).
Interestingly, while some treatments focus on directly reducing ATP levels, others may indirectly affect ATP concentration by inhibiting cell proliferation or inducing cell death, as seen with juglone, casticin, and adenosine treatments (Cui et al., 2017; Gao et al., 2016; Xie et al., 2011). These compounds lead to changes in cell cycle distribution and apoptosis, which would, in turn, impact ATP levels due to reduced cellular metabolism.
In summary, controlling ATP concentration in HeLa cells can be achieved through direct inhibition of ATP production or indirectly by targeting pathways that affect cell viability and proliferation. The use of synthetic ATP-binding proteins like DX represents a direct approach, while the effects of compounds such as juglone, BIIB021, casticin, and adenosine illustrate indirect strategies that ultimately influence ATP levels (Cui et al., 2017; Gao et al., 2016; Güven & Özgür, 2023; Khav et al., 2016; Luo et al., 2014; Xie et al., 2011).

Source Papers

BIIB021, an orally available and small-molecule inhibitor of HSP90, activates intrinsic apoptotic pathway in human cervical adenocarcinoma cell line (HeLa).

Heat shock protein 90 (HSP90) is a highly conserved ATP-dependent chaperone protein that plays a vital role in tumorigenesis. This study aims to investigate the apoptosis inducer role of BIIB021 (orally available HSP90 inhibitors) compound via inhibition of HSP90 activity in the human cervical cancer cell line (HeLa). The anticancer potential of BIIB021 was determined by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)] cell proliferation assay against the human cervical cancer cell line (HeLa). ATPase and luciferase aggregation assays were carried out to detect the HSP90 inhibitor potential of BIIB021. To determine the antiproliferative mechanism of the BIIB021, the expression level of the pro-apoptotic and antiapoptotic markers was determined by reverse transcription polymerase chain reaction (RT-PCR) and ELISA experiments. BIIB021 exhibited a cytotoxic effect on HeLa cell proliferation and the inhibitory concentration (IC)50 dose of BIIB021 was found to be 14.79 nM at 48 h. BIIB021 decreased the ATP hydrolysis rate of HSP90 and blocked the refolding of the desaturated luciferase in the presence of ATP. To understand the antiproliferative mechanism of the BIIB021 in HeLa cells, the mRNA and protein expression levels of the apoptotic markers [BCL-2 associated X (BAX), B-cell lymphoma 2 (BCL-2), cytochrome-c (CYT-c), and caspase-3 (CAS-3)] were determined by RT-PCR and ELISA experiments. The results obtained indicated that BIIB021 decreased BCL-2 levels and increased BAX, CYT-c, and CAS-3 levels in human cervical cancer cells. These results confirmed that BIIB021 inhibited the chaperone activity of HSP90, resulting in anti-proliferating effects in cervical cancer cells via the induction of the intrinsic apoptotic pathways.

Dosimetry study on photodynamic effect of PSD-007 on human cervical cancer cell line Hela

Objective To investigate the photochemotherapeutic effect and the main affecting factors of PSD-007 on human cervical cancer Hela in vitro.Methods Hela cells were treated with different concentrations of PSD-007 (0,3.125,6.25,12.5,25,50,100 μg/ml) for 2 h under the influence of low-level laser (635 nm) therapy at different doses (0,0.6,1.2,2.4,4.8,9.6 J/cm2).Then the OD values and survival rates of Hela cells were measured by MTT assay compared with breast cancer cells MCF-7 in same treatment.Hela cells were treated with 12.5 μg/ml of PSD-007 for 2 h and were treated with different intensities of laser (1.2,2.4,4.8 J/cm2).The cellular apoptosis rate and cell cycle phase distribution of Hela were measured by a flow cytometry (FCM).Results Survival rates of Hela cells declined with more than 25 μg/ml of PSD-007 only,and significant difference in the inhibitory between the PDT group and control group was observed (P<0.05).The survival rates of Hela after PDT was decreased by the concentration of sensitizer and dose of laser.There were no significant differences of cell survival rates among the groups with concentrations more than 12.5 μg/ml and laser energy density more than 4.8 J/cm2.The FCM assay showed a G0/G1 cell cycle arrest in a time-dependent manner.Conclusions PSD-007 has a photodynamic effect on Hela in vitro.Photodynamic effect of PSD-007 was more significant in Hela than MCF-7.Less photosensitizer and laser energy density were needed. Key words: Photodynamic therapy; Human cervical cancer cells; Hela; PSD-007

Abstract 214: Intracellular ATP depletion in cancer cells by a synthetic ATP-binding protein

Abstract Introduction: Altered cellular energy metabolism is a crucial characteristic of most cancers regardless of tissue or cellular origin. In contrast to normal cells, which generate most of their adenosine triphosphate (ATP) through oxidative phosphorylation, cancer cells are dependent on aerobic glycolysis to meet energy demands (Warburg effect). However, recent studies demonstrate an upregulation in mitochondrial activity (O2 consumption and ATP production) when cancer cells are subjected to stress, such as radiation/chemotherapy treatment. To understand the significance of ATP produced by oxidative phosphorylation in cancer cells, a synthetic ATP-binding protein, DX, was targeted to the mitochondria in HeLa cells to reduce bioavailable ATP. Hypothesis: Reduced available ATP, due to DX in the mitochondria of HeLa cells, will negatively affect cellular metabolism, viability and chemoresistance. Methods: For controlled expression, DX was cloned into the pcDNA™5/TO expression vector under the control of a tetracycline (Tet)-regulated promoter. The DX construct was designed to translocate into the matrix of the mitochondria using the mitochondria targeting sequence and the 3’ UTR of a nuclear SOD2 gene. Cultured T-REx™ HeLa cells (which stably express the Tet-repressor protein) were transfected with pcDNA™5/TO::DX-MITO. As a control, T-REx™ HeLa cells were transfected with the parent plasmid, pcDNA™5/TO, and cultured under identical conditions. RT-PCR was performed to confirm DX expression, while western blot analysis was performed to confirm DX localization to the mitochondria. The impact of DX on cell viability and morphology was assessed using a tetrazolium-based colorimetric assay, caspase 3/7 assay, and by light/fluorescent microscopy. To correlate phenotypic change with DX activity, the level of bioavailable ADP /ATP was measured at specific time points following DX induction. Results: RT-PCR and western blot analysis confirmed DX expression and translation in HeLa cells, respectively, following Tet induction. Cells expressing DX experienced a significant reduction in viability and alteration in morphology compared to control HeLa cells. Contemporaneous with DX expression, bioavailable ATP decreased and the levels of caspases 3/7 increased suggesting that a majority of cells undergo apoptosis in response to energy crisis. Conclusion: Reduced intracellular ATP levels, mediated by a synthetic ATP-binding protein, negatively affects the viability of cervical cancer cells. The consequence of this on biochemical pathways, mitochondrial function and cell viability requires further investigation. We suggest DX, could be used to control and regulate energy metabolism and represents a new approach for cancer chemotherapy. Citation Format: Eddie Khav, Bernardo Chavira, Matt Hamada, Nagaraj Vinay Janthakahalli, Shaleen Korch. Intracellular ATP depletion in cancer cells by a synthetic ATP-binding protein. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 214.

Abstract 3694: Metabolic response in human cervical cancer cells to modifications in bioavailable ATP

Abstract Introduction: Cancer cells utilize a markedly reduced oxidative phosphorylation (OXPHOS) when experiencing conditions of high oxygen stress (Warburg Effect/aerobic glycolysis), a phenomenon first studied by Otto Warburg. While there have been many discoveries associated with metabolic differences across cancer cells, one of the most common alterations is the primary means of generating ATP. The importance of deciphering these cellular decisions will enable an understanding of the multifaceted role ATP has in cancer proliferation, senescence, and chemotherapeutic resistance. The use of synthetic protein DX, a man-made ATP chelator with high specificity and affinity, is a proposed method of investigating the metabolic response in cancer cells. Hypothesis: Following DX expression, HeLa cells respond to energy stress (reduced intracellular ATP) via metabolic adaptations, specifically inducing the spare respiratory capacity. Methods: The impact of DX on cell viability was determined using a tetrazolium-based colorimetric cell viability assay and a caspase 3/7 assay. To correlate phenotypic/viability change with DX activity, bioavailable ATP levels were measured at specific time points following DX expression. Additionally, the relative contribution of glycolysis and OXPHOS to the total ATP production rate was measured using the label-free XF Real Time ATP Rate Assay and XF Cell Mito Stress Test (XFe96 Seahorse, Agilent Technologies) over time post DX expression. To determine the impact of ATP stress on mitochondrial and nuclear content, both were quantified following DX-expression. Results: In a time- and dose- dependent manner, DX negatively impacted cell growth and induced cell death via apoptosis, at a time concomitant with a decrease in bioavailable ATP. In response to DX over time, the total ATP production rates in HeLa cells significantly decreased. Importantly, this reduction in the rate of ATP production was associated with a significant downregulation in both OXPHOS and glycolysis. Conclusion: Advances in synthetic biology have allowed for the intentional design of artificial proteins that maintain function in vivo. These proteins can be developed into powerful investigative tools to study biological questions, such as cellular decisions involved in cancer cell metabolism. In response to DX-potentiated ATP stress, the significant reduction in both glycolysis and oxidative phosphorylation suggests metabolic downregulation is required to maintain HeLa cell viability. Citation Format: Parth K. Jayaswal, Taha Muhammad, Ashley Brown, Jeffrey Norris, Shaleen B. Korch. Metabolic response in human cervical cancer cells to modifications in bioavailable ATP. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3694.