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| 2. |
- Mallikarjuna, Pramod, et al.
(författare)
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Interactions between TGF-β type I receptor and hypoxia-inducible factor-alpha mediates a synergistic crosstalk leading to poor prognosis for patients with clear cell renal cell carcinoma
- 2019
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Ingår i: Cell Cycle. - : Taylor & Francis. - 1538-4101 .- 1551-4005. ; 18:17, s. 2141-2156
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the significance of expression of HIF-1 alpha, HIF-2 alpha, and SNAIL1 proteins; and TGF-beta signaling pathway proteins in ccRCC, their relation with clinicopathological parameters and patient's survival were examined. We also investigated potential crosstalk between HIF-alpha and TGF-beta signaling pathway, including the TGF-beta type 1 receptor (ALK5-FL) and the intracellular domain of ALK5 (ALK5-ICD). Tissue samples from 154 ccRCC patients and comparable adjacent kidney cortex samples from 38 patients were analyzed for HIF-1 alpha/2 alpha, TGF-beta signaling components, and SNAIL1 proteins by immunoblot. Protein expression of HIF-1 alpha and HIF-2 alpha were significantly higher, while SNAIL1 had similar expression levels in ccRCC compared with the kidney cortex. HIF-2 alpha associated with poor cancer-specific survival, while HIF-1 alpha and SNAIL1 did not associate with survival. Moreover, HIF-2 alpha positively correlated with ALK5-ICD, pSMAD2/3, and PAI-1; HIF-1 alpha positively correlated with pSMAD2/3; SNAIL1 positively correlated with ALK5-FL, ALK5-ICD, pSMAD2/3, PAI-1, and HIF-2 alpha. Intriguingly, in vitro experiments performed under normoxic conditions revealed that ALK5 interacts with HIF-1 alpha and HIF-2 alpha, and promotes their expression and the expression of their target genes GLUT1 and CA9, in a VHL dependent manner. We found that ALK5 induces expression of HIF-1 alpha and HIF-2 alpha, through its kinase activity. Under hypoxic conditions, HIF-alpha proteins correlated with the activated TGF-beta signaling pathway. In conclusion, we reveal that ALK5 plays a pivotal role in synergistic crosstalk between TGF-beta signaling and hypoxia pathway, and that the interaction between ALK5 and HIF-alpha contributes to tumor progression.
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| 3. |
- Mallikarjuna, Pramod, 1987-
(författare)
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The role of transforming growth factor‐β signaling and hypoxia‐inducible factors in renal cell carcinoma
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Renal cell carcinoma (RCC) is the cancer of the kidneys; about 1100 patients with RCC are diagnosed in Sweden each year. RCC can be classified into several subtypes, clear cell renal cell carcinoma (ccRCC) is most common accounting to about 70% of all RCCs, and also the most lethal; papillary renal cell carcinoma (pRCC) accounts to about 10%‐15%, while chromophobe renal cell carcinoma (chRCC) accounts to about 5% of all RCCs. There is a need to study the distinguishing features of RCC subtypes to design treatment. Von Hippel‐Lindau tumor suppressor gene (VHL) is often inactivated in ccRCC, unlike in pRCC or chRCC. Transforming growth factor‐β (TGF‐β) is a cytokine involved in various biological processes such as differentiation, proliferation, apoptosis, migration, andepithelial‐mesenchymal transition. TGF‐β exerts its functions through canonical (Smad‐dependent) and non‐canonical (Smadindependent) signaling pathways. In the first study, we have shown that both canonical and non‐canonical TGF‐β signaling pathways are associated with ccRCC tumor progression. VHL is known to have a dampening effect on TGF‐β signaling in RCC. However, the effects of pVHL status on the TGF‐β signaling pathway in ccRCC and non-ccRCC has not yet been studied in detail. In the second study, we have investigated the effects of the TGF‐β signaling pathway in the presence or absence of pVHL in ccRCC and non‐ccRCC. We show that, in ccRCC, VHL has an inhibiting effect exclusively on canonical TGF‐β signaling, and has no effect on non‐canonical TGF‐β signaling via ALK5‐ICD. In non‐ccRCC, TGF‐β signaling did not have an effect on tumor progression. Further, we demonstrate that VHL, through its ubiquitin ligases activity ubiquitinates ALK5 in a K48 dependent manner and subjects it to proteasomal degradation. During the normoxic conditions, VHL is implicated in ubiquitination and proteasomal degradation of Hypoxia‐inducible factors (HIFs). In hypoxic conditions or when the loss of VHL occurs, HIFs accumulates in the cytoplasm and enters the nucleus to initiate angiogenesis, cell proliferation, and tumor progression. In the third study, we have explored a potential synergistic cross‐talk between TGF‐β signaling and hypoxia in ccRCC. We demonstrate a correlation between TGF‐β signaling components and HIF‐1α/2α in ccRCC. We have also shown that TGF‐β signaling enhances the expression of HIF‐1α/2α and their target genes even under normoxic conditions, dependent on the kinase activity of ALK5 and dictated by the status of VHL. We present novel data that the synergistic crosstalk between hypoxia and TGF‐β is orchestrated through interactions between ALK5 and HIF‐1α/2α. HIF‐3α is only limited studied, compared with HIF‐1α and HIF‐2α. In the fourth study, we have analyzed the roles of HIF‐3α in ccRCC and pRCC and show that HIF‐3α is associated with advanced stage and metastasized tumors. We also found that HIF‐3α is associated with TRAF6, a crucial component of non‐canonical TGF‐β signaling.
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| 4. |
- Mallikarjuna, Pramod, et al.
(författare)
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VHL status regulates transforming growth factor-β signaling pathways in renal cell carcinoma
- 2018
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 9:23, s. 16297-16310
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the role of pVHL in the regulation of TGF-β signaling pathways in clear cell renal cell carcinoma (ccRCC) as well as in non-ccRCC; the expression of pVHL, and the TGF-β pathway components and their association with clinicopathological parameters and patient’s survival were explored. Tissue samples from 143 ccRCC and 58 non-ccRCC patients were examined by immunoblot. ccRCC cell lines were utilized for mechanistic in-vitro studies. Expression levels of pVHL were significantly lower in ccRCC compared with non-ccRCC. Non-ccRCC and ccRCC pVHL-High expressed similar levels of pVHL. Expression of the TGF-β type I receptor (ALK5) and intra-cellular domain were significantly higher in ccRCC compared with non-ccRCC. In non-ccRCC, expressions of ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 had no association with clinicopathological parameters and survival. In ccRCC pVHL-Low, ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 were significantly related with tumor stage, size, and survival. In ccRCC pVHL-High, the expression of PAI-1 was associated with stage and survival. In-vitro studies revealed that pVHL interacted with ALK5 to downregulate its expression through K48-linked poly-ubiquitination and proteasomal degradation, thus negatively controlling TGF-β induced cancer cell invasiveness. The pVHL status controls the ALK5 and can thereby regulate the TGF-β pathway, aggressiveness of tumors, and survival of the ccRCC and non-ccRCC patients.
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| 5. |
- Tumkur Sitaram, Raviprakash, 1974-, et al.
(författare)
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Role of Wnt Signaling Pathways in Clear Cell Renal Cell Carcinoma Pathogenesis in Relation to VHL and HIF Status
- 2020
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Ingår i: Clinical Oncology and Research. - 2613-4942. ; 3:3
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Forskningsöversikt (refereegranskat)abstract
- Renal cell carcinoma (RCC) encompasses various tumor types characterized by a variety of genetic abnormalities. The genetic changes, like mutations, deletions, and epigenetic alterations, can affect the signaling components and signaling networks, causing the modification of tumor pathogenesis and prognosis of RCC. The most prevalent RCC, clear cell RCC (ccRCC), is asymptomatic in the early stages, refractory to chemotherapy and radiation therapy, and has a poorer prognosis compared with the papillary and chromophobe ccRCC types. Loss of the VHL gene and upregulation of oxygen sensors, hypoxia-inducible factor alphas (HIF-α), which promote different growth factors, is a signature of sporadic ccRCC. The VHL-HIF-α and Wnt/β-catenin pathways are closely connected and contribute to the ontogeny of ccRCC. This review confines to ccRCC and the role of the Wnt/β-catenin signaling pathways and its crosstalk with VHL/HIF.
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| 6. |
- Tumkur Sitaram, Raviprakash, 1974-, et al.
(författare)
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Significance of PI3K Signalling pathway in clear cell renal cell carcinoma in relation to VHL and HIF status
- 2021
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Ingår i: Journal of Clinical Pathology. - : BMJ Publishing Group Ltd. - 0021-9746 .- 1472-4146. ; 74:4, s. 216-222
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Forskningsöversikt (refereegranskat)abstract
- Renal cell carcinoma (RCC) includes diverse tumor types characterized by various genetic abnormalities. The genetic changes, like mutations, deletions, and epigenetic alterations, play a crucial role in the modification of signaling networks, tumor pathogenesis, and prognosis. The most prevalent RCC type, clear cell RCC (ccRCC), is asymptomatic in the early stages and has a poorer prognosis compared with the papillary and the chromophobe typesRCCs. Generally, ccRCC is refractory to chemotherapy and radiation therapy. Loss of VHL gene and upregulation of hypoxia-inducible factors (HIF), the signature of most sporadic ccRCC, promote multiple growth factors. Hence, VHL/HIF and a variety of pathways, including PTEN/PI3K/AKT, are closely connected and contribute to the ontogeny of ccRCC. In the recent decade, multiple targeting agents have been developed based on blocking major signaling pathways directly or indirectly involved in ccRCC tumor progression, metastasis, angiogenesis, and survival. However, most of these drugs have limitations; either metastatic ccRCC develops resistance to these agents, or despite blocking receptors, tumor cells utilize alternate signaling pathways. This review compiles the state of knowledge about the PI3K/AKT signaling pathway confined to ccRCC and their cross-talks with VHL/HIF pathways.
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| 7. |
- Tumkur Sitaram, Raviprakash, 1974-, et al.
(författare)
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Transforming growth factor-β promotes aggressiveness and invasion of clear cell renal cell carcinoma
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:24, s. 35917-35931
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Tidskriftsartikel (refereegranskat)abstract
- The molecular mechanisms whereby transforming growth factor-β (TGF-β) promotes clear cell renal cell carcinoma (ccRCC) progression is elusive. The cell membrane bound TGF-β type I receptor (ALK5), was recently found to undergo proteolytic cleavage in aggressive prostate cancer cells, resulting in liberation and subsequent nuclear translocation of its intracellular domain (ICD), suggesting that ALK5-ICD might be a useful cancer biomarker. Herein, the possible correlation between ALK5 full length (ALK5-FL) and ALK5-ICD protein, phosphorylated Smad2/3 (pSmad2/3), and expression of TGF-β target gene PAI-1, was investigated in a clinical ccRCC material, in relation to tumor grade, stage, size and cancer specific survival. Expression of ALK5-FL, ALK5-ICD, pSmad2/3 and PAI-1 protein levels were significantly higher in higher stage and associated with adverse survival. ALK5-ICD, pSmad2/3 and PAI-1 correlated with higher grade, and ALK5-FL, pSmad2/3 and PAI-1 protein levels were significantly correlated with larger tumor size. Moreover, the functional role of the TGF-β - ALK5-ICD pathway were investigated in two ccRCC cell lines by treatment with ADAM/MMP2 inhibitor TAPI-2, which prevented TGF-β-induced ALK5-ICD generation, nuclear translocation, as well as cell invasion. The present study demonstrated that canonical TGF-β Smad2/3 pathway and generation of ALK5-ICD correlates with poor survival and invasion of ccRCC in vitro.
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