Morphoproteomic confirmation of a constitutively activated mTOR pathway in high grade prostatic intraepithelial neoplasia and prostate cancer

Preclinical studies have implicated the mammalian target of rapamycin (mTOR) pathway in the cell cycle progression and growth of prostate cancer cells. Downstream signaling from PI3'-K/Akt leads to phosphorylation (p) of mTOR at serine 2448 and to activation of its substrate, p70S6Kinase (p70S6K), phosphorylated on threonine 389. This promotes translation and cell cycle progression. Morphoproteomic analysis, that combines both the application of phosphospecific probes directed against putative sites of activation on protein analytes and cellular compartmentalization [1] was carried out on tissue microarray (TMA) slides from 64 cases of primary, previously untreated adenocarcinomas of the prostate. Gleason scores ranged from 6 to 10. High grade prostatic intraepithelial neoplasia (HGPIN), which accompanied the invasive cancer in 20 cases, and 15 non-neoplastic controls from benign prostatic hypertrophy specimens in a separate TMA were also included. Ninety-three percent (93%) of tumors exhibited moderate to strong cytoplasmic/plasmalemmal expression of p-mTOR and eighty-five percent (85%) showed similar staining intensity for p-p70S6K. HGPIN demonstrated comparable and occasionally, stronger expression levels for these protein analytes. Quantitative digital imaging revealed an overall increase in the mean expression levels in HGPIN, reaching statistical significance for p-mTOR (Ser 2448) at p<0.05. Morphoproteomic analysis confirms the constitutive activation of the mTOR pathway in prostate cancer and HGPIN, with relative overexpression of p-mTOR in HGPIN. These findings coincide with preclinical studies in supporting a role for the mTOR pathway in the biology and development of prostate cancer through its putative precursor lesion, HGPIN and in suggesting a potential therapeutic target.

The CD44 receptor is a molecular predictor of survival in ovarian cancer

PURPOSE

CD44 is a cell surface receptor implicated in cancer progression and metastases. Malignant tumors may show a loss of CD44 splice control mechanisms. We investigated the role of CD44 splice variant expression in ovarian tumors and metastases, and its association with survival.

EXPERIMENTAL DESIGN

We tested CD44 expression in 142 cases of epithelial carcinoma of the ovary and 265 metastatic sites by immunohistochemistry.

RESULTS

Survival analysis showed that the expression of CD44s, CD44-v4, -v5, -v6, -v9, and -v10 are significant predictors for survival in univariate analysis. After stage, the expression of CD44-v10 in metastases was the strongest predictor of decreased survival in multivariate analysis (p = 0.0009). Conversely, CD44-v10 expression in the primary tumor was an independent predictor of improved survival in multivariate analysis (p = 0.0002). The expression of CD44s in the tumor/stroma interface of the primary tumor was associated with improved survival (p < 0.0001).

CONCLUSIONS

CD44 variant expression is a molecular prognostic maker for epithelial ovarian carcinomas. CD44-v10 expression is an independent prognostic indicator and the site of expression determines a positive or negative influence in survival. Our results also indicate that CD44 may be involved in important tumor/stroma interactions.

NFkappaB: a pivotal transcription factor in prostate cancer metastasis to bone

Prostate cancers frequently metastasize to bone and this accounts for substantial morbidity. We investigated the potential role of the transcription factor NFkappaB as a central regulator of prostate cancer metastasis using the prostate adenocarcinoma cell line, PC-3, in a series of in vitro studies. Wild type PC-3 cells (PC-3.WT) have high basal levels of NFkappaB signaling, otherwise absent in PC-3 cells stably expressing a mutant form of the inhibitory kappa B (IkappaB) protein alpha (PC-3.mIkappaB). Although PC-3.WT cells in co-culture with rat bone marrow cells enhance bone resorption, no increase was observed in co-cultures with PC-3.mIkappaB cells. Similarly, although PC-3.WT cells were invasive in a chicken chorioallantoic membrane extravasation model, PC-3.mIkappaB cells lose this capacity to invade. NFkappaB reciprocally regulated genes involved in cellular invasion, with upregulation of MMP-9 and downregulation of its inhibitor, TIMP-1 in PC-3.WT cells, whereas MMP-9 was downregulated and TIMP-1 was upregulated in PC-3.mIkappaB cells. Finally, high basal gene and protein expression of the osteoclast-activating cytokine IL-6, observed in PC-3.WT cells, was absent in PC-3.mIkappaB cells. These in vitro experiments suggest NFkappaB as an important target to prevent prostate cancer bone metastasis and provide a rationale for further study of this transcription factor in metastatic disease.

Development of an animal model for prostate cancer cell metastasis to adult human bone

BACKGROUND

Prostate cancer metastases to bone are associated with significant morbidity and mortality. Presently, there is little known about the biological interaction between prostate cancer cells and bone. Development of an animal model using adult human bone will enhance our ability to study the biology of prostate cancer metastasis to bone.

METHODS

Bone was harvested from patients undergoing total joint arthroplasty and implanted in the hindlimbs of pre-treated SCID mice. Two months after bone implantation 4 x 104 prostate cancer cells (PC-3 or LAPC-4) were injected near the bone implantation site. The animals were sacrificed approximately 8 to 12 weeks after the injections of the cells. Complete histological analysis including immunostaining was performed.

RESULTS

Both the PC-3 and LAPC-4 prostate cancer cells homed to the human bone implant, specifically the reconstituted bone marrow cavity. Analysis of the bone-tumor interaction after injection of PC-3 cells revealed strong labeling for PTHrP, TNF alpha and IL-6, consistent with osteoclast recruitment and osteoclast activity. These cells also were positively stained for CK18. After cellular injection of LAPC-4 cells, there was strong labeling for TNF alpha, IL-6, and IL-1 (osteoclast recruitment and osteolytic activity). PTHrP staining was also noted. The bone cells were strongly stained for osteocalcin, and the tumor cells for PSA.

CONCLUSIONS

These data suggest that the tumor cells may induce an osteolytic response to enhance their ability to metastasize to bone. This animal model allows us to study the biologic interaction between prostate cancer cells and human bone and may enhance our understanding of the events associated with prostate cancer metastasis to bone.

A newly recognized entity: intraductal "oncocytic" papillary neoplasm of the pancreas

Intraductal papillary-mucinous tumors of the pancreas are increasingly recognized, and their characteristic endoscopic and radiological features are well reported in the literature in recent years. Oncocytic features in these tumors are uncommon and unrecognized. Intraductal oncocytic papillary neoplasm is a distinct pancreatic tumor and is a recently recognized entity. We report a case of a 69-yr-old patient who presented with symptoms mimicking pancreatitis, resulting in delay in the diagnosis of her pancreatic tumor. She underwent a successful Whipple's procedure and subsequently has remained well. The resected specimen showed an intraductal oncocytic papillary-mucinous neoplasm. The entity is new and the literature information is inadequate at present to judge the biological behavior of this tumor. We discuss this recently recognized entity.

Leiomyomatosis peritonealis disseminata, endometriosis, and multicystic mesothelioma: an unusual association

A 32-year-old, previously healthy woman with a diffuse, complex tumoral process is described. While she was being evaluated for primary infertility, a laparoscopic procedure revealed a disseminated peritoneal process associated with bilateral ovarian lesions. A clinical diagnosis of stage III ovarian cancer was made and total hysterectomy, bilateral salpingo-oophorectomy, and omentectomy were performed. Pathologic studies showed an admixture of leiomyomatosis peritonealis disseminata (LPD) endometriosis, and an extensive multicystic mesothelial proliferation. Although endometriosis is known to occur in conjunction with either LPD or multicystic mesothelioma, to our knowledge this is the first report of all three lesions occurring simultaneously.