The TP53-Induced Glycolysis and Apoptosis Regulator mediates cooperation between HTLV-1 p30II and the retroviral oncoproteins Tax and HBZ and is highly expressed in an in vivo xenograft model of HTLV-1-induced lymphoma

Abstract

The human T-cell leukemia virus type-1 (HTLV-1) is an oncoretrovirus that infects and transforms CD4+ T-cells and causes adult T-cell leukemia/lymphoma (ATLL) -an aggressive lymphoproliferative disease that is highly refractive to most anticancer therapies. The HTLV-1 proviral genome encodes several regulatory products within a conserved 3' nucleotide sequence, known as pX; however, it remains unclear how these factors might cooperate or dynamically interact in virus-infected cells. Here we demonstrate that the HTLV-1 latency-maintenance factor p30 induces the TP53-induced glycolysis and apoptosis regulator (TIGAR) and counters the oxidative stress, mitochondrial damage, and cytotoxicity caused by the viral oncoproteins Tax and HBZ. The p30 protein cooperates with Tax and HBZ and enhances their oncogenic potential in colony transformation/foci-formation assays. Further, we have shown that TIGAR is highly expressed in HTLV-1-induced tumors associated with oncogene dysregulation and increased angiogenesis in an in vivo xenograft model of HTLV-1-induced T-cell lymphoma. These findings provide the first evidence that p30 likely collaborates as an ancillary factor for the major oncoproteins Tax and HBZ during retroviral carcinogenesis.

The human T-cell leukemia virus type-1 tax oncoprotein dissociates NF-κB p65RelA-Stathmin complexes and causes catastrophic mitotic spindle damage and genomic instability

“…The Tax protein activates the IκK signalosome through binding to the scaffold subunit, NEMO or IκK-γ, via lysine K63linked polyubiquitin chains (Sun et al, 1994;Geleziunas et al, 1998;Harhaj et al, 2000Harhaj et al, , 2007Ho et al, 2015;Yamaoka et al, 1998;Shembade et al, 2007;Wu and Sun, 2007) and induces constitutive NF-κB-signaling which is essential for the survival and proliferation of HTLV-1-transformed tumor cells (Harhaj and Giam, 2018;Zhang et al, 2016;Choi and Harhaj, 2014;. However, hyperactivation of the NF-κB pathway by Tax has been shown to induce oxidative stress and cumulative DNA-damage (Baydoun et al, 2015;Belgnaoui et al, 2010;Durkin et al, 2008;Haoudi et al, 2003;Chaib-Mezrag et al, 2014;Kinjo et al, 2010;Hutchison et al, 2018;Takahashi et al, 2013;Los et al, 1998), resulting in cellular senescence and cytotoxicity (Kinjo et al, 2010;Hutchison et al, 2018;Kuo and Giam, 2006;Ho et al, 2012;Zhi et al, 2011;Nicot and Harrod, 2000;Takahashi et al, 2013;Los et al, 1998) which can be countered through its cooperation with other pX-encoded viral proteins (HBZ or p30 II ) that inhibit NF-κB transactivation (Hutchison et al, 2018;Zhi et al, 2011; see Fig. 1A, E, 1F, 2B, 5A, 5B, 7A-7F, 7H).…”

“…wildtype (wt) or ACH. p30 II mutant provirus, defective for p30 II production (Hutchison et al, 2018;Bartoe et al, 2000;Romeo et al, 2018;Kimata et al, 1994;Robek et al, 1998), were cotransfected with 0.25 μg of a tk-renillaluciferase plasmid and increasing amounts (0.1, 0.25, 0.5, and 0.75 μg) of an E-Selectin promoter-firefly-luciferase (A) or HIV-1 κB-LTR (ΔTAR)-firefly-luciferase reporter plasmid (B). Dual luciferase assays were carried out and the relative NF-κB-dependent firefly-luciferase activities were quantified and normalized for equivalent renilla-luciferase levels.…”

“…One distinguishing pathological feature of acute/lymphoma-stage ATLL is the presence of tumor lymphocytes with atypical pleomorphic or polylobate ("flowershaped") nuclei (Johnson et al, 2001;Bangham and Ratner, 2015). The viral transactivator protein Tax induces clastogenic DNA-damage and genomic instability through the generation of reactive oxygen species (ROS) and the inhibition of cellular DNA-damage surveillance and repair components, and by targeting various regulators of the cell-cycle checkpoints (Baydoun et al, 2015;Belgnaoui et al, 2010;Durkin et al, 2008;Haoudi et al, 2003;Chaib-Mezrag et al, 2014;Dayaram et al, 2013;Baydoun et al, 2015;Chaib-Mezrag et al, 2014;Majone and Jeang, 2000;Kinjo et al, 2010;Hutchison et al, 2018;Jin et al, 1998;Majone and Jeang, 2000;Liu et al, 2005;Kehn et al, 2005;Neuveut et al, 1998;Ching et al, 2006;Peloponese et al, 2005;Belgnaoui et al, https://doi.org/10.1016/j.virol.2019.07.003 Received 1 April 2019; Received in revised form 21 June 2019; Accepted 2 July 2019 2010; Durkin et al, 2008;Haoudi et al, 2003;Dayaram et al, 2013;Zane et al, 2012;Jin et al, 1998;Majone and Jeang, 2000;Liu et al, 2005;Kehn et al, 2005;Neuveut et al, 1998). Further, Tax activates NF-κB-dependent expression of the inducible Nitric oxide synthase (iNOS) which results in nitric oxide (NO) production and double-strand DNA breaks in HTLV-1-infected cells (Baydoun et al, 2015).…”

“…Whereas NF-κB transactivation is essential for the continuous proliferation and survival of HTLV-1-transformed lymphocytes (Harhaj and Giam, 2018;Zhang et al, 2016;Choi and Harhaj, 2014;, the hyperactivation of NF-κB-signaling by Tax induces DNA-damage that can lead to cellular senescence and apoptosis (Baydoun et al, 2015;Chaib-Mezrag et al, 2014;Kinjo et al, 2010;Kuo and Giam, 2006;Ho et al, 2012;Zhi et al, 2011;Nicot and Harrod, 2000;Takahashi et al, 2013;Los et al, 1998). We recently demonstrated in Hutchison et al (2018) that the HTLV-1 latency-maintenance factor p30 II (Nicot et al, 2004;Younis et al, 2004;Zhang et al, 2000;Bartoe et al, 2000) inhibits Tax-induced cytotoxicity and cooperates with the viral transactivator to promote oncogenic colony formation in vitro, dependent upon the activation of p53-regulated pro-survival signals, including the TP53-induced glycolysis and apoptosis regulator (TIGAR; Bensaad et al, 2006;Bensaad et al, 2009) which suppresses Tax-induced oxidative stress. p30 II interacts with the MYST-family acetyltransferase TIP60 (Awasthi et al, 2005;Romeo et al, 2015) and inhibits lysine K120acetylation of the p53 protein (Romeo et al, 2018) which differentially regulates the expression of p53-dependent pro-apoptotic genes (Sykes et al, 2006;Tang et al, 2006;Kurash et al, 2008;Dar et al, 2013;Xu et al, 2014).…”

“…p30 II interacts with the MYST-family acetyltransferase TIP60 (Awasthi et al, 2005;Romeo et al, 2015) and inhibits lysine K120acetylation of the p53 protein (Romeo et al, 2018) which differentially regulates the expression of p53-dependent pro-apoptotic genes (Sykes et al, 2006;Tang et al, 2006;Kurash et al, 2008;Dar et al, 2013;Xu et al, 2014). Interestingly, the p53 tumor suppressor is mutated in nearly half of all cancers; however, it is rarely mutated in HTLV-1+ ATLL clinical isolates which frequently contain high levels of wildtype p53 (Zane et al, 2012;b Pise-Masison et al, 1998;Tabakin-Fix et al, 2006;Mengle-Gaw and Rabbitts, 1987), suggesting the subversion of p53-regulated target genes may contribute to viral carcinogenesis (Hutchison et al, 2018;Romeo et al, 2018). Although there is currently no commercial antibody available to detect the p30 II protein, the alternatively-spliced pX-orfII-p30 mRNA has been detected by RT-PCR in chronically HTLV-1-infected T-cell-lines, primary uncultured ATLL clinical isolates, and PBMCs from asymptomatic carriers (Princler et al, 2003;Berneman et al, 1992;Koralnik et al, 1992;Ciminale et al, 1992).…”