KIF11 silencing and inhibition induces chromosome instability that may contribute to cancer

Abstract

Understanding the aberrant pathways that contribute to oncogenesis and identifying the altered genes involved in these pathways is a critical first step to develop effective strategies to better combat cancer. Chromosome instability (CIN) is an aberrant phenotype that occurs in ∼80% of all cancer types and is associated with aggressive tumors, the acquisition of multidrug resistance and poor patient prognosis. Despite these associations however, the aberrant genes and molecular defects underlying CIN remain poorly understood. KIF11 is an evolutionarily conserved microtubule motor protein that functions in centrosome and chromosome dynamics in mitosis. Interestingly, the yeast ortholog of KIF11, namely CIN8 is a CIN gene and thus aberrant KIF11 expression and function is suspected to underlie CIN. In support of this possibility, KIF11 is somatically altered in a large number of cancer types. Using a complementary biochemical and genetic approach we examined whether KIF11 silencing with siRNAs or inhibition with monastrol was able to convert two distinct and karyotypically stable cell lines into karyotypically unstable cell lines. Indeed, quantitative imaging microscopy and flow cytometry revealed that KIF11 silencing induced increases in nuclear areas, micronucleus formation, DNA content and chromosome numbers relative to controls that was also observed following KIF11 inhibition. Collectively, this study identifies and validates KIF11 as an evolutionarily conserved CIN gene, and further suggests that aberrant expression and function may contribute to the pathogenesis of a subset of cancers.

Reduced SKP1 Expression Induces Chromosome Instability through Aberrant Cyclin E1 Protein Turnover

“…To firmly establish the CIN phenotypes observed above were due to on-target effects, a distinct set of ON-TARGETplus (Dharmacon, Lafayette, CO, USA) siRNA duplexes were used for validation. To further show that the results are cell type independent, work was expanded into a third karyotypically stable cell line, HCT116, which has been used extensively in similar CIN-based studies [6,[21][22][23]. Western blots established the silencing efficiencies of all 10 genes ( Figure S2) and scQuantIM validated the results of the initial hTERT screen.…”

Chromosome Instability; Implications in Cancer Development, Progression, and Clinical Outcomes

“…Single cell approaches have also been developed to quantify and compare surrogate markers of CIN (e.g., CIN-associated phenotypes), including micronucleus formation [28,29] and changes in nuclear areas [29] or human artificial chromosomes [30]. Conceptually, micronuclei are extra nuclear bodies that are found outside the primary nucleus and are hallmarks of CIN that typically arise due to chromosome missegregation events [31][32][33], while changes in nuclear areas and human artificial chromosomes are associated with small and large (i.e., ploidy) scale changes in DNA content, respectively [30,[34][35][36][37][38]. These approaches typically involve quantitative imaging microscopy or flow cytometry that are each capable of rapidly assessing CIN-associated phenotypes in hundreds-to-thousands of cells [28,29,39].…”

“…In any case, endpoint approaches offer unparalleled insight into the level of cell-to-cell heterogeneity and population diversity associated with CIN. For example, these endpoint approaches and subsequent cytogenetic validation have been instrumental in expanding our understanding of the molecular determinants of CIN, which includes genes regulating chromosome cohesion and condensation [35,36,[40][41][42], histone modifications [43][44][45][46], microtubule motor proteins [34,47], and ubiquitin regulating complexes [37,48,49]. Only once these single cell approaches are more readily applied in both experimental and clinical contexts will we begin to expand our current understanding of the intimate and causal relationships existing between CIN and cancer so that we can ultimately realize its clinical potential in enhancing case management and predicting clinical outcomes.…”

“…In fact, of the~2300 CIN genes (i.e., genes whose aberrant expression induces CIN) predicted to exist [34,68], fewer than 150 have been identified and validated to date. Furthermore, of those that have been identified, most encode functions within intuitive pathways that orchestrate chromosome dynamics and/or DNA repair, including chromosome segregation [12,69], sister chromatid cohesion [36,40,41], chromosome condensation [35,42], mitotic spindle dynamics [69][70][71], spindle assembly/mitotic checkpoint [72][73][74][75], kinetochore-microtubule attachments [34,[76][77][78][79], centrosome dynamics [80][81][82], telomere biology [83][84][85], and DNA replication and repair [12,86,87]. Thus, significant efforts are required to greatly advance our limited understanding of the molecular determinants of CIN and their implications for cancer development, particularly as CIN pertains to intertumoral and intratumoral heterogeneity.…”

Meiotic arrest and spindle defects are associated with altered KIF11 expression in porcine oocytes

“…KIF11 regulates the spindle formation to actuate chromosomal separation, which is elemental for the establishment of the bipolar spindle and the isolation of sister chromatids in mitosis (Blangy et al, 1995;Kapitein et al, 2005). KIF11 suppression reduces chromosome stability and could induce tumorigenesis (Asbaghi et al, 2017). KIF11 knockdown hastens neuronal migration, while KIF11 overexpression slows neuronal migration (Falnikar et al, 2011).…”