scholarly journals Targeting the mitochondrial RNA methyltransferase TRMT61B reveals new therapeutic opportunities in aneuploid cancer cells

2021 ◽  
Author(s):  
Alberto Martin ◽  
Borja Vilaplana-Marti ◽  
Rocio IR Macias ◽  
Angel Martinez-Ramirez ◽  
Ana Cerezo ◽  
...  

Chromosomal instability (CIN) is an important source of genetic and phenotypic variation that has been extensively reported as a critical cancer related property that improves tumor cell adaptation and survival. CIN and its immediate consequence, aneuploidy, provoke adverse effects on cellular homeostasis that need to be overcome by developing efficient anti-stress mechanisms. Perturbations in these safeguard responses might be detrimental for cancer cells and represent an important tumor specific Achilles heel since CIN and aneuploidy are very rare events in normal cells. On the other hand, epitranscriptomic marks catalyzed by different RNA modifying enzymes have been found to change under several stress insults. Although CIN and aneuploidy are important intracellular stressors, their biological connection with RNA modifications is pending to be determined. In an in silico search for new cancer biomarkers, we have identified TRMT61B, a mitochondrial RNA methyltransferase enzyme, to be associated with high levels of aneuploidy. In the present work, we study the connection of this molecule with cancer and aneuploidy. First, we show increased protein amounts of TRMT61B in tumor cell lines with imbalanced karyotype as well as in different tumor types compared to unaffected control tissues. In addition, we demonstrate that depletion of TRMT61B in melanoma cells reduces cell proliferation either by fostering apoptosis and inhibiting autophagy in high-aneuploid (ANEhigh) cells or by inducing senescence in the case of low-aneuploid (ANElow) cell lines. Further, TRMT61B elimination compromises mitochondrial function and reduces the expression of several mitochondrial encoded proteins that are part of the electron transport chain. Finally, transwell and xenograft experiments revealed a reduced invasive and tumorigenic capacity upon TRMT61B depletion that strengthen the therapeutic value of this aneuploidy-associated biomarker. These results, which connect tumorigenesis, aneuploidy and mitochondrial RNA methylation, bring to the cancer field a new putative strategy to specifically target high aneuploid tumors.

Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4350
Author(s):  
Jessica Castro ◽  
Giusy Tornillo ◽  
Gerardo Ceada ◽  
Beatriz Ramos-Neble ◽  
Marlon Bravo ◽  
...  

Despite the significant advances in cancer research made in recent years, this disease remains one of the leading causes of death worldwide. In part, this is due to the fact that after therapy, a subpopulation of self-renewing tumor cells can survive and promote cancer relapse, resistance to therapies and metastasis. Targeting these cancer stem cells (CSCs) is therefore essential to improve the clinical outcome of cancer patients. In this sense, multi-targeted drugs may be promising agents targeting CSC-associated multifocal effects. We have previously constructed different human pancreatic ribonuclease (RNase) variants that are cytotoxic for tumor cells due to a non-classical nuclear localization signal introduced in their sequence. These cytotoxic RNases affect the expression of multiple genes involved in deregulated metabolic and signaling pathways in cancer cells and are highly cytotoxic for multidrug-resistant tumor cell lines. Here, we show that these cytotoxic nuclear-directed RNases are highly selective for tumor cell lines grown in 3D, inhibit CSCs’ development and diminish the self-renewal capacity of the CSCs population. Moreover, these human RNase variants reduce the migration and invasiveness of highly invasive breast cancer cells and downregulate N-cadherin expression.


2020 ◽  
Vol 41 (7) ◽  
pp. 894-903
Author(s):  
Yunyan Wu ◽  
Meixiang Sang ◽  
Fei Liu ◽  
Jiandong Zhang ◽  
Weijing Li ◽  
...  

Abstract Cancer testis antigens (CTAs) are promising targets for T cell-based immunotherapy and studies have shown that certain CT genes are epigenetically depressed in cancer cells through DNA demethylation. Melanoma-associated antigen A11 (MAGE-A11) is a CTA that is frequently expressed in esophageal cancer and is correlated with a poor esophageal cancer prognosis. Consequently, MAGE-A11 is a potential immunotherapy target. In this study, we evaluated MAGE-A11 expression in esophageal cancer cells and found that it was downregulated in several tumor cell lines, which restricted the effect of immunotherapy. Additionally, the specific recognition and lytic potential of cytotoxic T lymphocytes (CTLs) derived from the MAGE-A11 was determined. Specific CTLs could kill esophageal cancer cells expressing MAGE-A11 but rarely lysed MAGE-A11-negative tumor cells. Therefore, induction of MAGE-A11 expression is critical for CTLs recognition and lysis of esophageal cancer cells. Treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine increased MAGE-A11 expression in esophageal cancer cells and subsequently enhanced the cytotoxicity of MAGE-A11-specific CD8+T cells against cancer cell lines. Furthermore, we found that PD-L1 expression in esophageal cancer cells affected the antitumor function of CTLs. programmed death-1 (PD-1)/PD-L1 blockade could increase the specific CTL-induced lysis of HLA-A2+/MAGE-A11+ tumor cell lines treated with 5-aza-2′-deoxycytidine. These findings indicate that the treatment of tumor cells with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine augments MAGE-A11 expression in esophageal cancer cells. The combination of epigenetic modulation by 5-aza-2′-deoxycytidine and PD-1/PD-L1 blockade may be useful for T cell-based immunotherapy against esophageal cancer.


2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Xiaotian Sun ◽  
James M. Angelastro ◽  
David Merino ◽  
Qing Zhou ◽  
Markus D. Siegelin ◽  
...  

Abstract Survivin (BIRC5, product of the BIRC5 gene) is highly expressed in many tumor types and has been widely identified as a potential target for cancer therapy. However, effective anti-survivin drugs remain to be developed. Here we report that both vector-delivered and cell-penetrating dominant-negative (dn) forms of the transcription factor ATF5 that promote selective death of cancer cells in vitro and in vivo cause survivin depletion in tumor cell lines of varying origins. dn-ATF5 decreases levels of both survivin mRNA and protein. The depletion of survivin protein appears to be driven at least in part by enhanced proteasomal turnover and depletion of the deubiquitinase USP9X. Survivin loss is rapid and precedes the onset of cell death triggered by dn-ATF5. Although survivin downregulation is sufficient to drive tumor cell death, survivin over-expression does not rescue cancer cells from dn-ATF5-promoted apoptosis. This indicates that dn-ATF5 kills malignant cells by multiple mechanisms that include, but are not limited to, survivin depletion. Cell-penetrating forms of dn-ATF5 are currently being developed for potential therapeutic use and the present findings suggest that they may pose an advantage over treatments that target only survivin.


2015 ◽  
Vol 61 (1) ◽  
pp. 86-93 ◽  
Author(s):  
Natália Cristina Ciufa Kobayashi ◽  
Samuel Marcos Ribeiro de Noronha

Many theories have been proposed to explain the origins of cancer. Currently, evidences show that not every tumor cell is capable of initiating a tumor. Only a small part of the cancer cells, called cancer stem cells (CSCs), can generate a tumor identical to the original one, when removed from human tumors and transplanted into immunosuppressed mice. The name given to these cells comes from the resemblance to normal stem cells, except for the fact that their ability to divide is infinite. These cells are also affected by their microenvironment. Many of the signaling pathways, such as Wnt, Notch and Hedgehog, are altered in this tumoral subpopulation, which also contributes to abnormal proliferation. Researchers have found several markers for CSCs; however, much remains to be studied, or perhaps a universal marker does not even exist, since they vary among tumor types and even from patient to patient. It was also found that cancer stem cells are resistant to radiotherapy and chemotherapy. This may explain the re-emergence of the disease, since they are not completely eliminated and minimal amounts of CSCs can repopulate a tumor. Once the diagnosis in the early stages greatly increases the chances of curing cancer, identifying CSCs in tumors is a goal for the development of more effective treatments. The objective of this article is to discuss the origin of cancer according to the theory of stem cell cancer, as well as its markers and therapies used for treatment.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e14515-e14515
Author(s):  
Ioannis Gavvovidis ◽  
Matthias Leisegang ◽  
Jenifer Oduro ◽  
Matthias Obenaus ◽  
Eugen Leo ◽  
...  

e14515 Background: As cancer-testis antigens are self-antigens, T cells expressing high-affinity TCRs against such antigens are suppressed via negative thymic selection. Therefore, patient- or donor-derived TCRs are typically of low affinity and result in a reduced antitumor effect. Using our proprietary HuTCR platform, which consists of mouse lines carrying the full human TCR α/β loci in combination with common human HLA alleles, we have isolated high-affinity TCRs specific for the cancer-testis antigen MAGE-A1 and compared them to human-derived MAGE-A1-specific TCRs that are currently reported to be in clinical development. Furthermore, we validated MAGE-A1 as a potential cancer therapy target by using immunohistochemistry to evaluate expression in several major tumor types and healthy tissue. Methods: Using scRNAseq, TCRs were isolated from HuTCR mice. Human-derived MAGE-A1-specific TCR sequences were obtained from publicly available databases. All TCRs were expressed in primary human T cells as verified using peptide-MHC-multimer staining. Functional avidity of the TCRs was analyzed by coculture with T2 target cells loaded with titrated amounts of epitope peptides and measuring cytokine concentration by ELISA. Reactivity of TCRs to endogenously processed MAGE-A1 protein was assessed by co-culture with a panel of tumor cell lines varying in MAGE-A1 and/or MHC-class-I expression. MAGE-A1 expression on protein level was evaluated by immunohistochemistry. Results: Immunization of HuTCR mice with the antigen resulted in robust CD8+ T cell responses and several TCR clonotypes were identified by scRNAseq, with the majority of clonotypes being specific to the MAGE-A1-derived peptide KVLEYVIKV and TCR affinities ranging from 0.3 nM to 3 nM. By comparison, human-derived TCRs exhibited generally lower functional avidity from 3 nM to 60 nM. In addition, HuTCR-mouse-derived TCRs were more sensitive in recognition of tumor cell lines expressing low MAGE-A1 and/or HLA-A2. Immunohistochemical analysis of MAGE-A1 expression in healthy tissues demonstrated highly selective expression of MAGE-A1 in testis, only. Screening for expression confirmed that a significant proportion of several major cancer types expresses MAGE-A1 as reported by various other groups [reviewed in Curr Opin Cell Biol. 2015 December; 37: 1–8]. Conclusions: The HuTCR mouse platform allows for the generation of high-affinity MAGE-A1-specific TCRs with increased anti-tumor efficacy as compared to human-derived TCRs against the same cancer antigen. In addition, it was confirmed that MAGE-A1 has a highly selective expression pattern in healthy tissues (testis, only), but shows distinct expression in several major human tumor types.


Author(s):  
Mohamed El Gendy ◽  
Michael Weinfeld ◽  
Ahmed Abdoon

Background: Gold nanorods (GNRs) are very promising agents that have multiple applications in medicine and biology. However, the cytotoxic effects of GNRs have not been fully explored. Objective: Therefore, the main objective of this study was to determine the selective cytotoxic effect of GNRs towards several human tumor cell lines. Methods: To address this issue, three sizes of GNRs (10-nm, 25-nm, and 50-nm) were tested against two human tumor cell lines, namely, human hepatoma HepG2 and human prostate PC3 cancer cells. As GNRs are usually stored in soft tissues inside living bodies, we also tested the effect of GNRs on murine splenocyte viability. To determine if the GNRs displayed selectivity cytotoxicity towards cancer cells, active GNRs with the size showing the least cytotoxicity to splenocytes were then tested against a panel of 11 human tumor cell lines and two human non-tumor cell lines. Results: Our results showed that the most cytotoxic size of GNRs is 10-nm, followed by the 25-nm GNRs, while the 50-nm GNRs did not show a significant effect. In addition, the 25-nm GNRs were the least cytotoxic to splenocytes when tested for 24 and 48 h. These GNRs showed a selective cytotoxic effect to prostate cancer PC3 cells with median inhibitory concentration (IC50) = 8.3 + 0.37 µM, myeloblastic leukemia HL60 cells (IC50 = 19.7 + 0.89 µM), cervical cancer HeLa cells (IC50 = 24.6 + 0.37 µM), renal adenocarcinoma 786.0 cells (IC50 = 27.34 + 0.6 µM), and hepatoma HepG2 cells (IC50 = 27.79 + 0.03 µM) when compared to the effect on the non-tumor human cells; skin fibroblast BJ cell line (IC50 = 40.13 + 0.7 µM) or epithelial breast MCF10A cells (IC50 = 33.2 + 0.89 µM). A high selectivity indices (SI) were observed in GNRs-treated PC3 and HL60 cells with values ranging from 1.69 to 4.83, whereas moderate SIs were observed in GNRs-treated HeLa, 786.0, and HepG2 cells with values ranging from 1.19 to 1.63. Other cells did not show a similar selective effect, including human laryngeal HEp2 cells, colon HCT116, metastatic renal adenocarcinoma ACHN cells, and human breast cancer cells (MCF7, MDA-MB-231, and MDA-MB-468 cells). The effect of GNRs was confirmed using the colony formation assay and the effect was found to be cell cycle specific. Finally, it was shown that laser treatment can potentiate the cytotoxic effect of the 25-nm GNRs. Conclusion: GNRs are selective cytotoxic agents and they have the potential to act as candidate anticancer agents.


2020 ◽  
Vol 10 (14) ◽  
pp. 4854
Author(s):  
Zahra El-Schich ◽  
Birgit Janicke ◽  
Kersti Alm ◽  
Nishtman Dizeyi ◽  
Jenny L. Persson ◽  
...  

Breast cancer is the second most common cancer worldwide. Metastasis is the main reason for death in breast cancer, and today, there is a lack of methods to detect and isolate circulating tumor cells (CTCs), mainly due to their heterogeneity and rarity. There are some systems that are designed to detect rare epithelial cancer cells in whole blood based on the most common marker used today, the epithelial cell adhesion molecule (EpCAM). It has been shown that aggressive breast cancer metastases are of non-epithelial origin and are therefore not always detected using EpCAM as a marker. In the present study, we used an in vitro-based circulating tumor cell model comprising a collection of six breast cancer cell lines and white blood cell lines. We used digital holographic cytometry (DHC) to characterize and distinguish between the different cell types by area, volume and thickness. Here, we present significant differences in cell size-related parameters observed when comparing white blood cells and breast cancer cells by using DHC. In conclusion, DHC can be a powerful diagnostic tool for the characterization of CTCs in the blood.


PLoS Genetics ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. e1009873
Author(s):  
Akira Ohkubo ◽  
Lindsey Van Haute ◽  
Danielle L. Rudler ◽  
Maike Stentenbach ◽  
Florian A. Steiner ◽  
...  

Transcription of the human mitochondrial genome and correct processing of the two long polycistronic transcripts are crucial for oxidative phosphorylation. According to the tRNA punctuation model, nucleolytic processing of these large precursor transcripts occurs mainly through the excision of the tRNAs that flank most rRNAs and mRNAs. However, some mRNAs are not punctuated by tRNAs, and it remains largely unknown how these non-canonical junctions are resolved. The FASTK family proteins are emerging as key players in non-canonical RNA processing. Here, we have generated human cell lines carrying single or combined knockouts of several FASTK family members to investigate their roles in non-canonical RNA processing. The most striking phenotypes were obtained with loss of FASTKD4 and FASTKD5 and with their combined double knockout. Comprehensive mitochondrial transcriptome analyses of these cell lines revealed a defect in processing at several canonical and non-canonical RNA junctions, accompanied by an increase in specific antisense transcripts. Loss of FASTKD5 led to the most severe phenotype with marked defects in mitochondrial translation of key components of the electron transport chain complexes and in oxidative phosphorylation. We reveal that the FASTK protein family members are crucial regulators of non-canonical junction and non-coding mitochondrial RNA processing.


2021 ◽  
Author(s):  
mengyang zhang ◽  
dongxu lin ◽  
changcheng luo ◽  
pengyu wei ◽  
kai cui ◽  
...  

Abstract Background: RNA activation, as a method of regulating gene expression at the transcriptional level, is far less widely used than RNA interference because of the insufficient understanding of the mechanism and the unstable success rate. It is necessary to analyze the failure cases of RNA activation to promote the application of RNA activation. When we validated the saRNAs designed to induce KLK1 expression, we found that saKLK1-374 can up-regulate KLK1 expression in prostate tumor cell lines, but failed in normal prostate cell lines. In addition, we also found that saKLK1-374 inhibited the growth of prostate cancer cells, which seems to be the opposite of the function of KLK1. This article is about experimental research and analysis of these two issues.Methods: To determine whether the phenomenon that the RNA activation of normal cells is difficult to succeed is only valid when the target gene is KLK1, we used p21WAF1/CIP1 as the target gene to perform RNA activation experiments in normal prostate cells and prostate cancer cells. Next, to determine whether the above phenomenon exists in other tissues, we also performed RNA activation experiments with KLK1 and p21WAF1/CIP1 as target genes in normal cell lines and tumor cell lines derived from the bladder. We have also extended the time from transfection to the detection of target gene expression to evaluate whether a longer saRNA action time can change the phenomenon that saRNA fails to up-regulate target gene expression in normal cells. In terms of mechanism research, we used fluorescently labeled dsRNA to evaluate the transfection efficiency, and also detected the expression of Ago2 and IPO8 proteins. In another issue of saKLK1-374 inhibiting prostate cancer cells, we tested the ROS content and apoptosis levels of prostate cancer cells after saKLK1-374 transfection. We used recombinant KLK1 protein to directly interfere with prostate cancer cells as a positive control for KLK1 function research. In turn, we also used siRNA to inhibit the expression of KLK1 in prostate cancer cells to compare the growth of prostate cancer cells when KLK1 mRNA was up-regulated and reduced.Results: The p21WAF1/CIP1 gene could be significantly upregulated by saRNA in prostate cancer cell lines, but not in normal prostate cell lines. The expression of KLK1 in bladder-derived cell lines was extremely low and could not be induced by saRNA. The p21WAF1/CIP1 gene could be up-regulated by saRNA to a higher extent in bladder cancer cell lines, while it was up-regulated by saRNA in normal urothelial cell line to a lower extent. Prolonging the action time of saRNA could not change that saRNA failed to induce the expression of target genes in normal cell lines. Compared with tumor cell lines, normal cell lines had lower transfection efficiency or lower expression of Ago2 and IPO8. After being transfected with saKLK1-374, prostate cancer cells had increased ROS and increased levels of apoptosis. The recombinant KLK1 protein did not increase ROS in prostate cancer cells, nor did it inhibit their growth. Even though saKLK1-374 up-regulated the expression of KLK1 in prostate cancer cells, siRNA still suppressed the expression of KLK1 below the baseline level, and in this case, the growth of prostate cancer cells was still at a suppressed level.Conclusion: Normal cell lines may be more difficult to be successfully induced target gene expression than tumor cells due to low transfection efficiency or low Ago2 and IPO8 expression. In addition, although saKLK1-374 is designed to up-regulate the expression of KLK1, the reason that it inhibits the proliferation of prostate cancer cells is irrelevant to the up-regulated expression of KLK1.


2016 ◽  
Vol 113 (16) ◽  
pp. E2258-E2266 ◽  
Author(s):  
Melanie Pribisko ◽  
Joshua Palmer ◽  
Robert H. Grubbs ◽  
Harry B. Gray ◽  
John Termini ◽  
...  

We report derivatives of gallium(III) tris(pentafluorophenyl)corrole, 1 [Ga(tpfc)], with either sulfonic (2) or carboxylic acids (3, 4) as macrocyclic ring substituents: the aminocaproate derivative, 3 [Ga(ACtpfc)], demonstrated high cytotoxic activity against all NCI60 cell lines derived from nine tumor types and confirmed very high toxicity against melanoma cells, specifically the LOX IMVI and SK-MEL-28 cell lines. The toxicities of 1, 2, 3, and 4 [Ga(3-ctpfc)] toward prostate (DU-145), melanoma (SK-MEL-28), breast (MDA-MB-231), and ovarian (OVCAR-3) cancer cells revealed a dependence on the ring substituent: IC50 values ranged from 4.8 to >200 µM; and they correlated with the rates of uptake, extent of intracellular accumulation, and lipophilicity. Carboxylated corroles 3 and 4, which exhibited about 10-fold lower IC50 values (<20 µM) relative to previous analogs against all four cancer cell lines, displayed high efficacy (Emax = 0). Confocal fluorescence imaging revealed facile uptake of functionalized gallium corroles by all human cancer cells that followed the order: 4 >> 3 > 2 >> 1 (intracellular accumulation of gallium corroles was fastest in melanoma cells). We conclude that carboxylated gallium corroles are promising chemotherapeutics with the advantage that they also can be used for tumor imaging.


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