scholarly journals HIF-independent synthetic lethality between CDK4/6 inhibition and VHL loss across species

2019 ◽  
Vol 12 (601) ◽  
pp. eaay0482 ◽  
Author(s):  
Hilary E. Nicholson ◽  
Zeshan Tariq ◽  
Benjamin E. Housden ◽  
Rebecca B. Jennings ◽  
Laura A. Stransky ◽  
...  

Inactivation of the VHL tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, and causes the accumulation of hypoxia-inducible factor 2α (HIF-2α). HIF-2α inhibitors are effective in some ccRCC cases, but both de novo and acquired resistance have been observed in the laboratory and in the clinic. Here, we identified synthetic lethality between decreased activity of cyclin-dependent kinases 4 and 6 (CDK4/6) and VHL inactivation in two species (human and Drosophila) and across diverse human ccRCC cell lines in culture and xenografts. Although HIF-2α transcriptionally induced the CDK4/6 partner cyclin D1, HIF-2α was not required for the increased CDK4/6 requirement of VHL−/− ccRCC cells. Accordingly, the antiproliferative effects of CDK4/6 inhibition were synergistic with HIF-2α inhibition in HIF-2α–dependent VHL−/− ccRCC cells and not antagonistic with HIF-2α inhibition in HIF-2α–independent cells. These findings support testing CDK4/6 inhibitors as treatments for ccRCC, alone and in combination with HIF-2α inhibitors.

2021 ◽  
Author(s):  
Zhicheng Liu ◽  
Dongxu Lin ◽  
Linmeng Zhang ◽  
Chen Yang ◽  
Bin Guo ◽  
...  

Abstract Background The emerging of targeted therapies has revolutionized the treatment modalities of advanced clear cell renal cell carcinoma (ccRCC) over the past fifteen years. However, lack of personalized treatment limits the development of effective clinical guidelines and improvement of patient prognosis. In this study, large-scale genomic profiles of ccRCC cohorts were exploited for conducting an integrative analysis. Method Based on synthetic lethality (SL), a concept that simultaneous losses of two genes cause cell death while a single loss does not, we sought to develop a computational pipeline to infer potential SL partners of ccRCC. Drug response prediction were received from three pharmacological databases to select agents which are likely to be effective in precisely treating patients with target gene mutation. Results We developed a credible method to identify SL pairs and determined a list of 72 candidate pairs which might be utilized to selectively eliminate tumors with genetic aberrations through SL partners of specific mutations. Further analysis identified BRD4 and PRKDC as novel medicine targets for patients with BAP1 mutations. After mapping these target genes to comprehensive drug datasets, two agents (BI-2536 and PI-103) were found to have considerable therapeutic potential in BAP1 mutant tumors. Conclusion Overall, our findings provide insight into the overview of ccRCC mutation patterns and offer novel opportunities for improving individualized cancer treatment.


2021 ◽  
Vol 118 (39) ◽  
pp. e2106947118
Author(s):  
Ritesh K. Aggarwal ◽  
Rebecca A. Luchtel ◽  
Venkata Machha ◽  
Alexander Tischer ◽  
Yiyu Zou ◽  
...  

Reduced succinate dehydrogenase (SDH) activity resulting in adverse succinate accumulation was previously considered relevant only in 0.05 to 0.5% of kidney cancers associated with germline SDH mutations. Here, we sought to examine a broader role for SDH loss in kidney cancer pathogenesis/progression. We report that underexpression of SDH subunits resulting in accumulation of oncogenic succinate is a common feature in clear cell renal cell carcinoma (ccRCC) (∼80% of all kidney cancers), with a marked adverse impact on survival in ccRCC patients (n = 516). We show that SDH down-regulation is a critical brake in the TCA cycle during ccRCC pathogenesis and progression. In exploring mechanisms of SDH down-regulation in ccRCC, we report that Von Hippel-Lindau loss-induced hypoxia-inducible factor–dependent up-regulation of miR-210 causes direct inhibition of the SDHD transcript. Moreover, shallow deletion of SDHB occurs in ∼20% of ccRCC. We then demonstrate that SDH loss-induced succinate accumulation contributes to adverse loss of 5-hydroxymethylcytosine, gain of 5-methylcytosine, and enhanced invasiveness in ccRCC via inhibition of ten-eleven translocation (TET)-2 activity. Intriguingly, binding affinity between the catalytic domain of recombinant TET-2 and succinate was found to be very low, suggesting that the mechanism of succinate-induced attenuation of TET-2 activity is likely via product inhibition rather than competitive inhibition. Finally, exogenous ascorbic acid, a TET-activating demethylating agent, led to reversal of the above oncogenic effects of succinate in ccRCC cells. Collectively, our study demonstrates that functional SDH deficiency is a common adverse feature of ccRCC and not just limited to the kidney cancers associated with germline SDH mutations.


2008 ◽  
Vol 86 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Qingzhou Ji ◽  
Robert D. Burk

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene occurs in the majority of clear-cell renal cell carcinomas (RCCs). It was previously shown that VHL decreased the abundance of integrins α2, α5, and β1, which is consistent with VHL-associated changes in cell–cell and cell – extracellular matrix adhesions. We investigated the mechanism by which VHL downregulates integrins. Although VHL can target hypoxia-inducible factor alpha (HIFα) subunits for degradation, VHL-dependent reduction of integrins was independent of O2 concentration and HIFα levels. VHL reduced the half-lives of integrins, and this activity was blocked by proteasomal inhibition. Although ectopically expressed FLAG-VHL retained HIFα degradation activity, it neither downregulated integrins nor promoted adherens and tight intercellular junctions, in contrast to expressed wild-type VHL. Moreover, integrins co-immunoprecipitated with wild-type VHL, but not FLAG-VHL. These data indicate that the downregulation of integrins by VHL is distinct from the regulation of HIFα subunits by VHL, and suggests that the loss of this activity contributes to VHL-associated RCC development through disruption of adherens and tight junctions.


Oncotarget ◽  
2015 ◽  
Vol 6 (6) ◽  
pp. 4066-4079 ◽  
Author(s):  
Wei Xiang ◽  
Jun He ◽  
Chao Huang ◽  
Lejun Chen ◽  
Dan Tao ◽  
...  

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