Noncoding RNA Ginir functions as an oncogene by associating with centrosomal proteins.

Long noncoding RNAs constitute a major fraction of the eukaryotic transcriptome, and together with proteins, they intricately fine-tune various growth regulatory signals to control cellular homeostasis. Here, we describe the functional characterisation of a novel pair of long intergenic noncoding RNAs (lincRNAs) comprised of complementary, fully overlapping sense and antisense transcripts Genomic Instability Inducing RNA (Ginir) and antisense RNA of Ginir (Giniras), respectively, from mouse cells. This transcript pair is expressed in a spatiotemporal manner during embryonic development. The individual levels of the sense and antisense transcripts are finely balanced during embryonic growth and in adult tissues. Functional studies of the individual transcripts performed using overexpression and knock-down strategies in mouse cells has led to the discovery that Ginir RNA is a regulator of cellular proliferation and can act as an oncogene having a preeminent role in malignant transformation. Mechanistically, we demonstrate that the oncogenic function of Ginir is mediated by its interaction with centrosomal protein 112 (Cep112). Additionally, we establish here a specific interaction between Cep112 with breast cancer type 1 susceptibility protein (Brca1), another centrosome-associated protein. Next, we prove that the mutual interaction between Cep112 with Brca1 is significant for mitotic regulation and maintenance of genomic stability. Furthermore, we demonstrate that the Cep112 protein interaction with Brca1 protein is impaired when an elevated level of Ginir RNA is present in the cells, resulting in severe deregulation and abnormality in mitosis, leading to malignant transformation. Inhibiting the Ginir RNA function in transformed cells attenuates transformation and restores genomic stability. Together, these findings unravel, to our knowledge, a hitherto-unknown mechanism of oncogenesis mediated by a long noncoding RNA and establishes a unique role of Cep112-Brca1 interaction being modulated by Ginir RNA in maintaining mitotic fidelity.

Impact of Chemotherapeutic Stress Depends on The Nature of Breast Cancer Spheroid and Induce Behavioral Plasticity to Resistant Population.

Cellular or tumor dormancy, identified recently as one of the main reasons behind post-therapy recurrence, can be caused by diverse reasons. Chemotherapy has recently been recognized as one of such reasons. However, in-depth studies of chemotherapy-induced dormancy are lacking due to the absence of an in vitro human-relevant model tailor-made for such a scenario. This report utilized multicellular breast cancer spheroid to create a primary platform for establishing a chemotherapy-induced dormancy model. It is observed that extreme chemotherapeutic stress affects invasive and non-invasive spheroids differently. Non-invasive spheroids exhibit more resilience and maintain viability and migrational ability, while invasive spheroids display heightened susceptibility and improved tumorigenic capacity. Heterogenous spheroids exhibit increased tumorigenic capacity while show minimal survival ability. Further probing of chemotherapeutically dormant spheroids is needed to understand the molecular mechanism and identify dormancy-related markers to achieve therapeutic success in the future.

Inherent aggressive character of invasive and non-invasive cells dictates the in vitro migration pattern of multicellular spheroid.

Cellular migration, a process relevant to metastasis, is mostly studied in the conventional 2D condition. However, cells cultured in the 3D condition assumed to mimic the in vivo conditions better. The current study is designed to compare an invasive and non-invasive adenocarcinoma cell with an invasive fibrosarcoma cell to understand the migration pattern of the multicellular spheroid. It is observed that conventional haplotaxis, chemotactic and pseudo-3D migration assay cannot distinguish between the invasive and non-invasive cells conclusively under 2D condition. Invasive spheroids migrate rapidly in sprouting assay in comparison to non-invasive spheroids. Effects of cytochalasin B, marimastat and blebbistatin are tested to determine the influence of different migration modality namely actin polymerization, matrix metalloprotease and acto-myosin in both culture conditions. Altered mRNA profile of cellular migration related genes (FAK, Talin, Paxillin, p130cas and Vinculin) is observed between 2D and 3D condition followed by the changed expression of matrix metallo proteases. A distinct difference is observed in distribution and formation of focal adhesion complex under these culture conditions. This study demonstrates the efficacy of multicellular spheroids in identifying the intrinsic aggressive behavior of different cell lines as a proof of concept and recognizes the potential of spheroids as a migration model.