Reduction of QM protein expression correlates with tumor grade in prostatic adenocarcinoma

Abstract

The QM protein is a transcription cofactor inhibiting the activity of AP-1 transcription factors and is also a ribosomal protein participating in protein synthesis. While protein synthesis is known to be increased in many cancers, inhibition of AP-1 activity presumably suppresses development and growth of sex-hormone-regulated tumor cells. The present study is the first report on immunohistochemical data of QM in human prostatic tissues. Paraffin sections of human prostate cancer samples were immunohistochemically stained for QM. The staining scores were analyzed with the clinicopathologic data of the patients. QM protein expression was found in all normal prostate glands adjacent to prostate cancer and in various intraepithelial neoplasia (PIN). In prostate cancer, the staining intensity and stained areas were decreased, compared to the normal glands and PIN lesions; in high-grade tumors only some patches of tumor cells showed positivity. Intense (3 þ ) staining was mostly observed in the Gleason grade three areas (48%) compared to grade 4 and 5 areas (22%), although both low and high-grade tumors showed similar percentages of weakly stained areas. Moreover, staining in prostatic adenocarcinoma was often topographically patchy and varied from negative or weak (1 þ ) to intense (3 þ ). There was an inverse correlation from normal to low-grade tumors and then to high-grade tumors. However, in high-grade tumors, the positive areas were mostly confined to peripheral aspects of tumors and were particularly strong in foci of perineural invasion. This preliminary study suggests that decreased QM expression may be associated with early development of prostate cancer, but later a high level of QM may facilitate progression of the tumors to a more aggressive phenotype.

Spermatogenesis Associated Retrogenes Are Expressed in the Human Ovary and Ovarian Cancers

“…The RPL10 is also a tumor suppressor gene and the protein it encodes is known as the tumor suppression protein QM[24]. Reduced RPL10 expression is associated with increasing grade of prostatic adenocarcinoma[25]. Primers specific to RPL10L and RPL39L were used to screen for expression of these testis specific retrogenes in a panel of ovarian cancers (Table 2; Fig.…”

Cooperative down-regulation of ribosomal protein L10 and NF-κB signaling pathway is responsible for the anti-proliferative effects by DMAPT in pancreatic cancer cells

“…So far, the importance of ribosome function and translational control in tumorigenesis has been underscored although several oncogenes, such as Myc [25], and tumor suppressor genes, such as PTEN [26] and p53 [27], have been linked to direct regulation of ribosome production and protein translation. In prostate cancer patients, reduced expression of RPL10 has been suggested to associate with early development of the cancer; however, high expression of RPL10 at later stages of cancer development could drive forward to a more aggressive phenotype [28]. More importantly, mutations in RPL10 gene have been recently detected in cancer patients who are unrelated to any heritable diseases [29].…”

Loss of heterozygosity and microsatellite instability at the Xq28 and the A/G heterozygosity of the QM gene are associated with ovarian cancer

“…We have recently shown that the decrease in QM protein level, determined by immunohistochemistry, is associated with tumor grade of prostate cancer. 26 Together, these results suggest that QM or a gene at the Xq28 may be a tumor suppressor gene, and its decreased expression could be due to alterations at the genetic level (such as LOH or MSI), transcriptional level or translational level and could be related to the development of ovarian cancer.…”