Lymphangiogenesis is thought to be essential for
cancer progression, making it an important target in
cancer therapy. Lymphangiogenic factors (
VEGF-C and
VEGF-D) are upregulated in various
tumors/
cancers, and play an important role in lymphangiogenesis and
lymph node metastasis. Similarly,
semaphorin 4D (
Sema4D) is a potent inducer of angiogenesis, and its overexpression is associated with
tumor progression and poor prognosis in a variety of
malignancies. However, little is known regarding the functional relationship between
Sema4D and
VEGF-C/
VEGF-D and in the mediation of lymphangiogenesis and
lymph node metastasis and clinical outcome. The current study aimed to evaluate the effect of
Sema4D expression on outcome in patients with
cervical cancer, and to explore the molecular mechanism of
Sema4D in
tumor progression. We evaluated
Sema4D expression, density of lymphatic vessels, and invasion of lymphatic vessels with immunohistochemical methods in 232 human
cervical cancers with long-term follow-up.
Sema4D expression was correlated with patho-clinical parameters and patients' outcome. A
cervical cancer cell line was used to investigate the contribution of
sema4D to
tumor progression by studying the role of
Sema4D in
VEGF-C/-D and cell migration using reverse transcription-polymerase chain reaction and Western blotting. We observed that
Sema4D expression was higher in metastatic
cervical cancer than in nonmetastatic
cervical cancer (P<0.001). CD34-positive or D2-40-positive lymphatic vessel density was significantly increased in cases with
lymph node metastasis compared with those without
lymph node metastasis. The increased
Sema4D expression was associated with
VEGF-C/-D, the presence of lymphatic invasion, the occurrence of
lymph node metastasis, and FIGO stage. We also observed a novel association between
Sema4D upregulation and poor prognosis in
cervical cancer. In vitro, the
Sema4D inhibitory antibody and Sema4D-shRNA suppressed
VEGF-C and
VEGF-D in the human cervical
carcinoma cell lines HeLa, Siha, and Caski cells. Invasiveness assay demonstrated that
Sema4D could augment the invasive potential of the
tumor cells in the
cervical cancer lines and induction of cellular invasiveness by
Sema4D stimulation could be inhibited by knockdown of plexinB1 by
siRNA. Further mechanistic investigations of
tumor cell invasiveness showed that
Sema4D could induce activation of
GTPase Ras homolog gene family, member A (RhoA), MAPK and AKT. In addition, plexinB1 knockdown by
siRNA could suppress the
Sema4D signal transmitted to MAPK and Akt. Taken together, these results suggest that
Sema4D autocrine within
tumor cells contributes to enhanced invasion and
tumor progression through increased motility of
cervical cancer and
VEGF-C/-D-mediated lymphangiogenesis.
Sema4D might be useful as a molecular marker of poor prognosis in
cervical cancer.