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ACH YEAR 471 000 CASES AND 233 000 deaths occur from cervical cancer worldwide, of which 80% occur in less-developed countries that have access to less than 5% of global cancer treatment resources. 1 The lifetime risk of a woman developing cervical cancer in a lowresource setting is approximately 2% to 4%. [2][3][4] Cytology-based screening programs have markedly reduced the incidence of cervical cancer in developed countries that have the infrastructure to support these programs. 5 However, screening programs have proven difficult to implement in low-resource settings. There are 2 predominant reasons why cytology-based programs have proven difficult to implement and sustain in low-resource settings. One is the nature of the screening test. 6 Highquality cytology laboratories are difficult to maintain and there are often substantial delays before the results become available. 7 Another is the extensive workup that is typically used for women with abnormal cytological results. In developed countries, women with abnor-

The Karyopherin proteins are involved in nucleo-cytoplasmic trafficking and are critical for protein and RNA subcellular localization. Recent studies suggest they are important in nuclear envelope component assembly, mitosis and replication. Since these are all critical cellular functions, alterations in the expression of the Karyopherins may have an impact on the biology of cancer cells. In this study, we examined the expression of the Karyopherins, Crm1, Karyopherin b1 (Kpnb1) and Karyopherin a2 (Kpna2), in cervical tissue and cell lines. The functional significance of these proteins to cancer cells was investigated using individual siRNAs to inhibit their expression. Microarrays, quantitative RT-PCR and immunofluorescence revealed significantly higher expression of Crm1, Kpnb1 and Kpna2 in cervical cancer compared to normal tissue. Expression levels were similarly elevated in cervical cancer cell lines compared to normal cells, and in transformed epithelial and fibroblast cells. Inhibition of Crm1 and Kpnb1 in cancer cells significantly reduced cell proliferation, while Kpna2 inhibition had no effect. Noncancer cells were unaffected by the inhibition of Crm1 and Kpnb1. The reduction in proliferation of cancer cells was associated with an increase in a subG1 population by cell cycle analysis and Caspase-3/7 assays revealed increased apoptosis. Crm1 and Kpnb1 siRNA-induced apoptosis was accompanied by an increase in the levels of growth inhibitory proteins, p53, p27, p21 and p18. Our results demonstrate that Crm1, Kpnb1 and Kpna2 are overexpressed in cervical cancer and that inhibiting the expression of Crm1 and Kpnb1, not Kpna2, induces cancer cell death, making Crm1 and Kpnb1 promising candidates as both biomarkers and potential anticancer therapeutic targets. ' 2008 Wiley-Liss, Inc.Key words: cervical cancer; nuclear transport proteins; Crm1; Karyopherin b1; Karyopherin a2Cervical cancer is the second most common cancer among women worldwide, 1 with nearly 80% of cases occurring in developing countries. 2 The primary risk factor in the development of the disease is infection with the Human Papillomavirus (HPV), 3,4 and more than 90% of cervical cancers carry high-risk HPV DNA. 4,5 The HPV E6 and E7 oncoproteins are responsible for cancer development, and evidence has shown that they alone are sufficient to immortalize human foreskin keratinocytes. 6 Their continued expression is essential for maintaining the transformed state. 6 HPV E6 and E7 promote cellular transformation by binding to and blocking the functions of the cell cycle regulatory proteins, p53 and pRb, respectively. 7,8 Prophylactic vaccines against lowrisk (HPV6, 11) and high-risk (HPV16 and 18) HPV types have recently been developed. 9 They rely on the vaccination of women before exposure to the virus; hence, their benefit to women already infected with HPV is still unclear, as well as their benefit to women infected with HPV types other than HPV6, 11, 16 and 18.Although the high-risk HPV proteins are the causative agents behind cervical cance...

Cervical cancer screening strategies that incorporate DVI or HPV DNA testing and eliminate colposcopy may offer attractive alternatives to cytology-based screening programs in low-resource settings.