Cell Proliferation and Epidermal Growth Factor Signaling in Non-small Cell Lung Adenocarcinoma Cell Lines Are Dependent on Rin1

Abstract

Rin1 is a Rab5 guanine nucleotide exchange factor that plays an important role in Ras-activated endocytosis and growth factor receptor trafficking in fibroblasts. In this study, we show that Rin1 is expressed at high levels in a large number of non-small cell lung adenocarcinoma cell lines, including Hop62, H650, HCC4006, HCC827, EKVX, HCC2935, and A549. Rin1 depletion from A549 cells resulted in a decrease in cell proliferation that was correlated to a decrease in epidermal growth factor receptor (EGFR) signaling. Expression of wild type Rin1 but not the Rab5 guanine nucleotide exchange factor-deficient Rin1 (Rin1⌬) complemented the Rin1 depletion effects, and overexpression of Rin1⌬ had a dominant negative effect on cell proliferation. Rin1 depletion stabilized the cell surface levels of EGFR, suggesting that internalization was necessary for robust signaling in A549 cells. In support of this conclusion, introduction of either dominant negative Rab5 or dominant negative dynamin decreased A549 proliferation and EGFR signaling. These data demonstrate that proper internalization and endocytic trafficking are critical for EGFR-mediated signaling in A549 cells and suggest that up-regulation of Rin1 in A549 cell lines may contribute to their proliferative nature. Internalization of epidermal growth factor receptors (EGFR)2 and their subsequent delivery to lysosomes play key roles in attenuating EGF-mediated signaling cascades (1, 2). The proper delivery of EGFR into lysosomes for degradation requires a series of highly regulated targeting and delivery events. Following ligand binding, EGFR is internalized via endocytic vesicles that are subsequently targeted to early endosomes. This targeting event is mediated by the small GTPase, Rab5 (3, 4). Once delivered to the early endosome, receptors that are destined for degradation are incorporated into vesicles that bud into the lumen of the endosome, forming the multivesicular body (reviewed in Refs. 5, 6). Sequestration of the activated cytoplasmic domain of EGFR into the intralumenal vesicles of the multivesicular body effectively terminates receptor signaling (7). Subsequent fusion of the multivesicular body with lysosomes delivers the intralumenal vesicles and their contents into the lumen of the lysosome where they are degraded (reviewed in Refs. 8 -10). Inactivating mutations in Rab5 disrupt the delivery of cell surface receptors, such as EGFR, to early endosomes, thereby inhibiting receptor trafficking to the lysosome and receptor degradation (11,12). Therefore, activation of Rab5 is a key point of regulation for EGFR signaling.Rab5 cycles between an inactive GDP-bound state and an active GTP-bound state, and Rab5 activation requires the exchange of GDP to GTP. This exchange is catalyzed by guanine nucleotide exchange factors (GEFs) that are specific to the Rab5 family of proteins (reviewed in Ref. 13). Rab5 family GEFs all contain a catalytic vacuolar protein sorting 9 (Vps9) domain that facilitates the GDP to GTP exchange (14 -17). Many Rab5 GEFs contain other fu...

Genomic profiles and CRTC1–MAML2 fusion distinguish different subtypes of mucoepidermoid carcinoma

“…23 The 11q12.2-q13.2 and 19p13.2-p13.11 segments contain several cancer-associated genes such as RIN1, FOSL1, and VEGFB (11q12.2-q13.2) and JUNB and JUND (19p13.2-p13.11) that are duplicated/rearranged and/or overexpressed in various forms of epithelial cancers. [30][31][32] Whether the 11q and 19p gains in mucoepidermoid carcinoma target any of these genes remains, however, to be shown. The most frequent copy number alterations detected in the 28 mucoepidermoid carcinomas were losses of 18q12.2-qter, 9p21.3, 6q22.1-q23.1, and 8pter-p12.1, and gains of 8q24.3, 11q12.3-q13.2, 3q26.1-q28, 19p13.2-p13.11, and 8q11.1-q12.2.…”

Endocytosis and Cancer

“…In colorectal tumors, Rin1 expression correlated not only with poor prognosis but also with venous invasion (Senda et al 2007). Congruent with growth-factor-driven invasiveness and metastasis, studies performed on lung cancer cell lines suggested that Rin1 regulates cell proliferation through EGFR (Tomshine et al 2009). These observations suggest that the interactions between Rin1 and Abl are favored in tumors more so than the alternative actions of Rin1 on Rab5 and Raf.…”

Laricitrin suppresses increased benzo(a)pyrene-induced lung tumor-associated monocyte-derived dendritic cell cancer progression

“…The present study investigated the association between certain factors and the effect of BaP on lung cancer progression. Table I shows the background of the cell lines used in the present study (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). A previous study using CD-1 mice indicated that female mice are more susceptible to the carcinogenic effects of BaP compared with males (29).…”

“…Comparison between each TADC-CM and mdDC-CM indicated that HCC2935-TADC-CM had the most marked effect on the proliferation, migration and invasion of cancer cells. The HCC2935 cell line was established from the pleural effusion cells of an adenocarcinoma patient (18)(19)(20)(21)(22). Lung cancer with malignant pleural effusion indicates terminal-stage disease (36).…”