Browsing by Author "Gogna, Rajan"

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    Cell competition and tumor heterogeneity
    (Elsevier, 2019) Parker, Taylor M.; Henriques, Vanessa; Beltran, Antonio; Nakshatri, Harikrishna; Gogna, Rajan; Surgery, School of Medicine
    Cancers exhibit a remarkable degree of intratumoral heterogeneity (ITH), which results from complex cellular interactions amongst various cell types. This phenomenon provides an opportunity for clonal selection and growth advantages to aggressive cancer cell types, resulting in worse prognosis and challenges to anti-cancer therapy. Cell competition is a conserved mechanism operational in cellular and organ systems, which allows neighboring cells to compare their relative fitness levels and results in the elimination of viable but suboptimal cells. By abuse of this conserved homeostasis mechanism, aggressive cancer cell types gain an advantage over normal cell types by achieving traits like increased proliferation, de-differentiation, and stemness. This review presents recent evidence that cell competition mechanisms actively participate in the regulation of intratumoral cell-cell interactions and thus contribute to ITH, and this process is essential for cancer development and progression.
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    The curcumin analog HO-3867 selectively kills cancer cells by converting mutant p53 protein to transcriptionally active wildtype p53
    (American Society for Biochemistry and Molecular Biology, 2018-03-23) Madan, Esha; Parker, Taylor M.; Bauer, Matthias R.; Dhiman, Alisha; Pelham, Christopher J.; Nagane, Masaki; Kuppusamy, M. Lakshmi; Holmes, Matti; Holmes, Thomas R.; Shaik, Kranti; Shee, Kevin; Kiparoidze, Salome; Smith, Sean D.; Park, Yu-Soon A.; Gomm, Jennifer J.; Jones, Louise J.; Tomás, Ana R.; Cunha, Ana C.; Selvendiran, Karuppaiyah; Hansen, Laura A.; Fersht, Alan R.; Hideg, Kálmán; Gogna, Rajan; Kuppusamy, Periannan; Surgery, School of Medicine
    p53 is an important tumor-suppressor protein that is mutated in more than 50% of cancers. Strategies for restoring normal p53 function are complicated by the oncogenic properties of mutant p53 and have not met with clinical success. To counteract mutant p53 activity, a variety of drugs with the potential to reconvert mutant p53 to an active wildtype form have been developed. However, these drugs are associated with various negative effects such as cellular toxicity, nonspecific binding to other proteins, and inability to induce a wildtype p53 response in cancer tissue. Here, we report on the effects of a curcumin analog, HO-3867, on p53 activity in cancer cells from different origins. We found that HO-3867 covalently binds to mutant p53, initiates a wildtype p53-like anticancer genetic response, is exclusively cytotoxic toward cancer cells, and exhibits high anticancer efficacy in tumor models. In conclusion, HO-3867 is a p53 mutant-reactivating drug with high clinical anticancer potential.
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    HIF-transcribed p53 chaperones HIF-1α
    (Oxford University Press, 2019-11-04) Madan, Esha; Parker, Taylor M.; Pelham, Christopher J.; Palma, Antonio M.; Peixoto, Maria L.; Nagane, Masaki; Chandaria, Aliya; Tomás, Ana R.; Canas-Marques, Rita; Henriques, Vanessa; Galzerano, Antonio; Cabral-Teixeira, Joaquim; Selvendiran, Karuppaiyah; Kuppusamy, Periannan; Carvalho, Carlos; Beltran, Antonio; Moreno, Eduardo; Pati, Uttam K.; Gogna, Rajan; Surgery, School of Medicine
    Chronic hypoxia is associated with a variety of physiological conditions such as rheumatoid arthritis, ischemia/reperfusion injury, stroke, diabetic vasculopathy, epilepsy and cancer. At the molecular level, hypoxia manifests its effects via activation of HIF-dependent transcription. On the other hand, an important transcription factor p53, which controls a myriad of biological functions, is rendered transcriptionally inactive under hypoxic conditions. p53 and HIF-1α are known to share a mysterious relationship and play an ambiguous role in the regulation of hypoxia-induced cellular changes. Here we demonstrate a novel pathway where HIF-1α transcriptionally upregulates both WT and MT p53 by binding to five response elements in p53 promoter. In hypoxic cells, this HIF-1α-induced p53 is transcriptionally inefficient but is abundantly available for protein-protein interactions. Further, both WT and MT p53 proteins bind and chaperone HIF-1α to stabilize its binding at its downstream DNA response elements. This p53-induced chaperoning of HIF-1α increases synthesis of HIF-regulated genes and thus the efficiency of hypoxia-induced molecular changes. This basic biology finding has important implications not only in the design of anti-cancer strategies but also for other physiological conditions where hypoxia results in disease manifestation.
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    Molecular Classification of Bladder Urothelial Carcinoma Using NanoString-Based Gene Expression Analysis
    (MDPI, 2021-11-01) Lopez-Beltran, Antonio; Blanca, Ana; Cimadamore, Alessia; Gogna, Rajan; Montironi, Rodolfo; Cheng, Liang; Pathology and Laboratory Medicine, School of Medicine
    Molecular classification of bladder carcinoma is a relevant topic in modern bladder cancer oncology due to its potential to improve oncological outcomes. The available molecular classifications are generally based on transcriptomic profiles, generating highly diverse categories with limited correlation. Implementation of molecular classification in practice is typically limited due to the high complexity of the required technology, the elevated costs, and the limited availability of this technology worldwide. We have conducted a gene expression analysis using a four-gene panel related to luminal and basal subtypes in a series of 91 bladder cancer cases. NanoString-based gene expression analysis using typically luminal (GATA3+/KRT20+) and basal markers (KRT14+/KRT5+/GATA3low/-/KRT20low/-) classified urothelial bladder carcinoma samples as luminal, basal, and a third category (KRT14-/KRT5-/GATA3-/KRT20-), null/double negative (non-luminal/non-basal). These three categories were meaningful in terms of overall cancer-specific survival (p < 0.0001) or when classified as conventional urothelial carcinoma and variant histology urothelial carcinoma (p < 0.0001), NMIBC vs. MIBC (p < 0.001), or by AJCC stage category Ta (p = 0.0012) and T1 (p < 0.0001) but did not reach significance in T2-T4 (p = 0.563). PD-L1 expression (low vs. high) was also different according to molecular subtype, with high PD-L1 expression mostly seen in basal and null subtypes and carcinomas with variant histology (p = 0.002). Additionally, the luminal subtype was enriched in NMIBC with favorable cancer-specific survival (p < 0.0001). In contrast, basal and null subtypes resulted in aggressive MIBC tumors with shorter cancer-specific survival (p < 0.0001), some of which presented variant histology. In conclusion, a comprehensive evaluation of a gene classifier related to molecular taxonomy using NanoString technology is feasible. Therefore, it might represent an accessible and affordable tool in this rapidly expanding area of precision genomics.