Elevated mRNA expression of CHAC1 splicing variants is associated with poor outcome for breast and ovarian cancer patients.

BACKGROUND: The role of CHAC1 (cation transport regulator-like protein 1), a recently identified component of the unfolded protein response (UPR) pathway, in gynaecological cancers has not yet been characterised. Now, this work illustrates CHAC1 mRNA expression and associated clinical outcome in breast and ovarian cancer. METHODS: The prognostic value of CHAC1 and its two transcript variants was investigated in 116 breast and 133 ovarian tissues using quantitative real-time reverse-transcriptase PCR. Subsequently, we conducted functional studies using short-interfering RNA-mediated knockdown and plasmid-mediated overexpression of CHAC1 in breast and ovarian cancer cells. RESULTS: Poorly differentiated tumours exhibited higher CHAC1 mRNA expression (breast cancer: P=0.004; ovarian cancer: P=0.024). Hormone receptor-negative breast tumours and advanced-staged ovarian cancers demonstrated elevated CHAC1 mRNA expression levels (P<0.001 and P=0.026, respectively). The multivariate survival analysis showed a prognostic value of both transcript variants in breast cancer (transcript variant 1: RR(death) 6.7 (2.4-18.9); P<0.001), RR(relapse) 6.7 (2.1-21.3); P=0.001); (transcript variant 2: RR(death) 4.9 (2.0-12.4); P<0.001), RR(relapse) 8.0 (2.4-26.8); P<0.001). Ovarian cancer patients aged younger than 62.6 years with high CHAC1 mRNA expression showed poorer relapse-free- and overall-survival (P=0.030 and P=0.012, respectively). In functional studies CHAC1 knockdown suppressed cell migration, whereas ectopic overexpression opposed these effects. CONCLUSION: High CHAC1 mRNA expression could be an independent indicator for elevated risk of cancer recurrence in breast and ovarian cancer.

Glucocorticoid-induced apoptosis and glucocorticoid resistance: molecular mechanisms and clinical relevance.

The ability of glucocorticoids (GC) to efficiently kill lymphoid cells has led to their inclusion in essentially all chemotherapy protocols for lymphoid malignancies. This review summarizes recent findings related to the molecular basis of GC-induced apoptosis and GC resistance, and discusses their potential clinical implications. Accumulating evidence suggests that GC may induce cell death via different pathways resulting in apoptotic or necrotic morphologies, depending on the availability/responsiveness of the apoptotic machinery. The former might result from regulation of typical apoptosis genes such as members of the Bcl-2 family, the latter from detrimental GC effects on essential cellular functions possibly perpetuated by GC receptor (GR) autoinduction. Although other possibilities exist, GC resistance might frequently result from defective GR expression, perhaps the most efficient means to target multiple antileukemic GC effects. Numerous novel drug combinations are currently being tested to prevent resistance and improve GC efficacy in the therapy of lymphoid malignancies.