Biomedical subjects

Anuradha S Budhu

Publications and source records attributed to Anuradha S Budhu.

3 recordsLinked to original sources

PubMed2005

Loading and unloading: orchestrating centrosome duplication and spindle assembly by Ran/Crm1.

The cell cycle is an intricate process of DNA replication and cell division that concludes with the formation of two genetically equivalent daughter cells. In this progression, the centrosome is duplicated once and only once during the G1/S transition to produce the bipolar spindle and ensure proper chromosome segregation. The presence of multiple centrosomes in cancer cells suggests that this process is mis-regulated during carcinogenesis. This suggests that certain factors exist that license the progression of centrosome duplication and serve to inhibit further duplications during a single cell cycle. Recent studies suggest that the Ran/Crm1 complex not only regulates nucleocytoplasmic transport but is also independently involved in mitotic spindle assembly. Factors that are capable of interacting with Ran/Crm1 through their nuclear export sequences, such as cyclins/cdks, p53 and Brca1/2, may potentially function as centrosome checkpoints akin to the G1/S and G2/M checkpoints of the cell cycle. Our recent findings indicate that nucleophosmin, a protein whose trafficking is mediated by the Ran/Crm1 network, is one of such checkpoint factors for maintaining proper centrosome duplication. We propose that Ran/Crm1 may act as a 'loading dock' to coordinate various checkpoint factors in regulating the fidelity of centrosome duplication during cell cycle progression, and the disruption of these processes may lead to genomic instability and an acceleration of oncogenesis.

Animals↗

PubMed2005

The molecular signature of metastases of human hepatocellular carcinoma.

The current metastasis paradigm suggests that the primary tumor starts off benign but over time slowly acquires changes that provide a few rare cells within the tumor the ability to metastasize. However, this concept has been challenged by several recent studies using the microarray-based approach. We have recently found that the molecular signature of primary hepatocellular carcinoma (HCC) is very similar to that of their corresponding metastases, while it differs significantly in primary HCCs with or without metastasis. Similar findings are also evident in primary cancers of the lung, breast, and prostate. Such a signature can be used to predict the prognosis of HCC patients. Moreover, there are significant differences in the gene expression profiles of liver parenchyma among HCC patients with or without intrahepatic metastases. These findings imply that many of the metastasis-promoting genes are embedded in the primary tumors and that the ability to metastasize may be an inherent quality of the tumor from the beginning. In addition, the condition of liver parenchyma may dictate the intrahepatic metastasis potential, which is consistent with the hypothesis that the degree of viral-hepatitis-mediated liver damage or possibly the genetic makeup of individuals may play an important role in metastasis.

Biomarkers, Tumor↗

PubMed2002

Direct channeling of retinoic acid between cellular retinoic acid-binding protein II and retinoic acid receptor sensitizes mammary carcinoma cells to retinoic acid-induced growth arrest.

Cellular retinoic acid-binding protein II (CRABP-II) is an intracellular lipid-binding protein that associates with retinoic acid with a subnanomolar affinity. We previously showed that CRABP-II enhances the transcriptional activity of the nuclear receptor with which it shares a common ligand, namely, the retinoic acid receptor (RAR), and we suggested that it may act by delivering retinoic acid to this receptor. Here, the mechanisms underlying the effects of CRABP-II on the transcriptional activity of RAR and the functional consequences of these effects were studied. We show that CRABP-II, a predominantly cytosolic protein, massively undergoes nuclear localization upon binding of retinoic acid; that it interacts with RAR in a ligand-dependent fashion; and that, in the presence of retinoic acid, the CRABP-II-RAR complex is a short-lived intermediate. The data establish that potentiation of the transcriptional activity of RAR stems directly from the ability of CRABP-II to channel retinoic acid to the receptor. We demonstrate further that overexpression of CRABP-II in MCF-7 mammary carcinoma cells dramatically enhances their sensitivity to retinoic acid-induced growth inhibition. Conversely, diminished expression of CRABP-II renders these cells retinoic acid resistant. Taken together, the data unequivocally establish the function of CRABP-II in modulating the RAR-mediated biological activities of retinoic acid.

Animals↗