Interleukin-12 in multimodal tumor therapies for induction of anti-tumor immunity.

Interleukin-12 (IL-12) can be used as an immunomodulator in cancer immunotherapy. And it has demonstrated enormous potential in inhibiting tumor growth and improving the tumor microenvironment (TME) by several preclinical models. However, some disappointing results have showed in the early clinical trials when IL-12 used as a single agent for systemic cancer therapy. Combination therapy is an effective way to significantly fulfill the great potential of IL-12 as an immunomodulator. Here, we discuss the effects of IL-12 combined with traditional methods (chemotherapy, radiotherapy and surgery), targeted therapy or immunotherapy in the preclinical and clinical studies. Moreover, we summarized the potential mechanism underlying the anti-tumor effect of IL-12 in the combination strategies. And we also discussed the delivery methods and tumor-targeted modification of IL-12 and outlines future prospects for IL-12 as an immunomodulator.

Identification of Notch signaling pathway gene mutations as a prognostic biomarker for bladder cancer.

Purpose: The authors aimed to identify Notch signaling pathway gene mutations as a prognostic biomarker for bladder cancer. Methods: First, critical Notch signaling pathway genes were screened using The Cancer Genome Atlas and validation sets. Second, immune infiltration, protein-protein interaction network, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis analyses were performed. Finally, potential immunotherapy drug targets were screened using T-cell receptors, B-cell receptors and CERES scores for bladder cancer. Results: The NOTCH7 gene was identified, with a significant difference in immune infiltration level between mutant and wild type in bladder cancer, mainly related to T cells. NOTCH7 was an immunotherapy prognostic factor, and IRF1 and B2M were the potential drug targets for NOTCH7 mutation in bladder cancer. Conclusion: NOTCH7 gene mutation can be used as an immunotherapy biomarker for bladder cancer.

Lay abstract Studies have shown that 43% of bladder cancer patients harbor somatic mutations in genes associated with the Notch signaling pathway. However, it is not clear whether these mutations impact the efficacy of immunotherapy in bladder cancer patients. In the present study, the authors aimed to elucidate whether Notch signaling pathway gene mutations are effective biomarkers for predicting immunotherapy response and prognosis in patients with bladder cancer. Results of the present study suggested that seven genes ­ CNTN6, CREBBP, EP300, NCOR1, NCOR2, NOTCH2 and SPEN ­ involved in the Notch signaling pathway can be used to predict the response of patients to immunotherapy. In addition, IRF1 and B2M can act as combination drug targets with these seven genes.

Genetic landscape of breast cancer and mutation tracking with circulating tumor DNA in Chinese women.

Considerable efforts have been devoted to exploring the breast cancer mutational landscape to understand its genetic complexity. However, no studies have yet comprehensively elucidated the molecular characterization of breast tumors in Chinese women. This study aimed to determine the potential clinical utility of peripheral blood assessment for circulating tumor-derived DNA (ctDNA) and comprehensively characterize the female Chinese population's genetic mutational spectrum. We used Omi-Seq to create cancer profiles of 273 patients enrolled at The First Affiliated Hospital of Wenzhou Medical University. The gene landscape results indicate PIK3CA and TP53 as the most frequently detected genes, followed by ERBB2, in Chinese breast cancer patients. The accuracy of ERBB2 copy number variations in tissue/formalin-fixed and paraffin-embedded samples was 95% with 86% sensitivity and 99% specificity. Moreover, mutation numbers varied between different molecular cell-free DNA subtypes, with the basal-like patients harboring a higher number of variants than the luminal patients. Furthermore, ratio changes in the max ctDNA allele fraction highly correlated with clinical response measurements, including cancer relapse and metastasis. Our data demonstrate that ctDNA characterization using the Omi-Seq platform can extend the capacity of personalized clinical cancer management.

Erratum: Overcoming erlotinib resistance in EGFR mutation-positive lung adenocarcinomas through repression of phosphoglycerate dehydrogenase: Erratum.

[This corrects the article DOI: 10.7150/thno.23177.].

Targeting the Hsp90-Cdc37-client protein interaction to disrupt Hsp90 chaperone machinery.

Heat shock protein 90 (Hsp90) is a critical molecular chaperone protein that regulates the folding, maturation, and stability of a wide variety of proteins. In recent years, the development of Hsp90-directed inhibitors has grown rapidly, and many of these inhibitors have entered clinical trials. In parallel, the functional dissection of the Hsp90 chaperone machinery has highlighted the activity disruption of Hsp90 co-chaperone as a potential target. With the roles of Hsp90 co-chaperones being elucidated, cell division cycle 37 (Cdc37), a ubiquitous co-chaperone of Hsp90 that directs the selective client proteins into the Hsp90 chaperone cycle, shows great promise. Moreover, the Hsp90-Cdc37-client interaction contributes to the regulation of cellular response and cellular growth and is more essential to tumor tissues than normal tissues. Herein, we discuss the current understanding of the clients of Hsp90-Cdc37, the interaction of Hsp90-Cdc37-client protein, and the therapeutic possibilities of targeting Hsp90-Cdc37-client protein interaction as a strategy to inhibit Hsp90 chaperone machinery to present new insights on alternative ways of inhibiting Hsp90 chaperone machinery.

Overcoming erlotinib resistance in EGFR mutation-positive lung adenocarcinomas through repression of phosphoglycerate dehydrogenase.

How to improve the efficacy and reverse the resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as erlotinib, remains a major challenge in the targeted therapy of lung adenocarcinoma with EGFR-activating mutation. Phosphoglycerate dehydrogenase (PHGDH) is the key enzyme of de novo serine biosynthesis over-expressed in various types of cancer including lung cancer. Elevated PHGDH expression is correlated with a worse overall survival in clinical lung adenocarcinoma patients. Here we investigated the role of PHGDH in lung adenocarcinoma with the acquisition of resistance to erlotinib. Methods: The necessary genes required for the acquired erlotinib resistance in lung adenocarcinoma cells were screened out by RNA-Seq analysis. Then the protein and mRNA levels of PHGDH were confirmed by immunoblotting and qRT-PCR in the erlotinib resistant cells. The effects of PHGDH inhibition or overexpression on erlotinib resistance were examined using cell culture and tumor xenograft mouse models respectively. To explore mechanism, the ROS level and DNA damage marker, γH2AX, were tested by DCFH-DA staining and immunofluorescence after PHGDH inhibition. Results: We found that PHGDH level was significantly increased in the lung adenocarcinoma PC9ER4 and HCC827ER9 cells that acquired resistance to erlotinib. Perturbation of PHGDH by siPHGDH transfection or NCT-503, a small molecular PHGDH inhibitor, synergistically augmented the tumoricidal effect and restored sensitivity to erlotinib in cell lines and xenografts. Over-expression of PHGDH caused xenografts resistant to erlotinib. Furthermore, multiple DNA damage repair pathways related genes were changed by PHGDH depletion specifically in erlotinib resistant cells. ROS stress and DNA damage marker γH2AX were enhanced by siPHGDH and NCT-503, which was reversed by NAC. Conclusion: Our study indicated that PHGDH inhibition has potential therapeutic value in lung adenocarcinoma with the acquired resistance to EGFR-TKIs.

Cell-free circulating tumor DNA in cancer.

Cancer is a common cause of death worldwide. Despite significant advances in cancer treatments, the morbidity and mortality are still enormous. Tumor heterogeneity, especially intratumoral heterogeneity, is a significant reason underlying difficulties in tumor treatment and failure of a number of current therapeutic modalities, even of molecularly targeted therapies. The development of a virtually noninvasive "liquid biopsy" from the blood has been attempted to characterize tumor heterogeneity. This review focuses on cell-free circulating tumor DNA (ctDNA) in the bloodstream as a versatile biomarker. ctDNA analysis is an evolving field with many new methods being developed and optimized to be able to successfully extract and analyze ctDNA, which has vast clinical applications. ctDNA has the potential to accurately genotype the tumor and identify personalized genetic and epigenetic alterations of the entire tumor. In addition, ctDNA has the potential to accurately monitor tumor burden and treatment response, while also being able to monitor minimal residual disease, reducing the need for harmful adjuvant chemotherapy and allowing more rapid detection of relapse. There are still many challenges that need to be overcome prior to this biomarker getting wide adoption in the clinical world, including optimization, standardization, and large multicenter trials.

A Systematic Review of the Anticancer Properties of Compounds Isolated from Licorice (Gancao).

Licorice (Gancao in Chinese) has been used worldwide as a botanical source in medicine and as a sweetening agent in food products for thousands of years. Triterpene saponins and flavonoids are its main ingredients that exhibit a variety of biological activities, including hepatoprotective, antiulcer, anti-inflammatory, antiviral and anticancer effects among others. This review attempts to summarize the current knowledge on the anticancer properties and mechanisms of the compounds isolated from licorice and obtain new insights for further research and development of licorice. A broad spectrum of in vitro and in vivo studies have recently demonstrated that the mixed extracts and purified compounds from licorice exhibit evident anticancer properties by inhibition of proliferation, induction of cell cycle arrest, apoptosis, autophagy, differentiation, suppression of metastasis, angiogenesis, and sensitization of chemotherapy or radiotherapy. A combined treatment of licorice compounds and clinical chemotherapy drugs remarkably enhances anticancer effects and reduces the side effects of chemotherapeutics. Furthermore, glycyrrhizic acid and glycyrrhetinic acid in licorice have been indicated to present obvious liver-targeting effects in targeted drug delivery systems for hepatocellular carcinoma treatment.

Elusive liver factor that causes pancreatic α cell hyperplasia: A review of literature.

Tumors and cancers of the gastrointestinal tract and pancreas are commonly derived from precursor lesions so that understanding the physiological, cellular, and molecular mechanisms underlying the pathogenesis of precursor lesions is critical for the prevention and treatment of those neoplasms. Pancreatic neuroendocrine tumors (PNETs) can also be derived from precursor lesions. Pancreatic α cell hyperplasia (ACH), a specific and overwhelming increase in the number of α cells, is a precursor lesion leading to PNET pathogenesis. One of the 3 subtypes of ACH, reactive ACH is caused by glucagon signaling disruption and invariably evolves into PNETs. In this article, the existing work on the mechanisms underlying reactive ACH pathogenesis is reviewed. It is clear that the liver secretes a humoral factor regulating α cell numbers but the identity of the liver factor remains elusive. Potential approaches to identify the liver factor are discussed.

FoxM1 transactivates PTTG1 and promotes colorectal cancer cell migration and invasion.

BACKGROUND: Metastasis is the major cause of cancer-related death. Forkhead Box M1 (FoxM1) is a master regulator of tumor metastasis. This study aims to identify new FoxM1 targets in regulating tumor metastasis using bioinformatics tools as well as biological experiments. METHODS: Illumina microarray was used to profile WT and PTTG1 knockout HCT116 cells. R2 Genomics Analysis was used to identify PTTG1 as a potential FoxM1 targeted gene. Luciferase reporter array, EMSA and Chromatin Immunoprecipitation (ChIP) were used to determine the binding of FoxM1 to PTTG1 promoter. Boyden chamber assay was used to evaluate the effects of FoxM1-PTTG1 on cell migration and invasion. Splenic-injection induced liver metastasis model was used to evaluate the effects of FoxM1-PTTG1 on liver metastasis of colorectal cancer. RESULTS: Analyses of multiple microarray datasets derived from human colorectal cancer indicated that correlation levels of FoxM1 and pituitary tumor transforming gene (PTTG1) are highly concordant (R = 0.68 ~ 0.89, p = 2.1E-226 ~ 9.6E-86). FoxM1 over-expression increased and knock-down decreased PTTG1 expression. Luciferase reporter assay identified that the -600 to -300 bp region of PTTG1 promoter is important for FoxM1 to enhance PTTG1 promoter activity. EMSA and ChIP assays confirmed that FoxM1 directly binds to PTTG1 promoter at the -391 to -385 bp region in colorectal cancer cells. Boyden chamber assay indicated that both FoxM1 and PTTG1 regulate migration and invasion of HCT116 and SW620 colorectal cancer cells. Further in vivo assays indicated that PTTG1 knock out decreased the liver metastasis of FoxM1 over-expressing HCT116 cells. Microarray analyses identified 662 genes (FDR < 0.05) differentially expressed between WT and PTTG1(-/-) HCT116 cells. Among them, dickkopf homolog 1 (DKK1), a known WNT pathway inhibitor, was suppressed by PTTG1 and FoxM1. CONCLUSIONS: PTTG1 is a FoxM1 targeted gene. FoxM1 binds to PTTG1 promoter to enhance PTTG1 transcription, and FoxM1-PTTG1 pathway promotes colorectal cancer migration and invasion.

Glycyrrhetinic Acid triggers a protective autophagy by activation of extracellular regulated protein kinases in hepatocellular carcinoma cells.

Glycyrrhetinic acid (GA), one of the main constituents of the famous Chinese medicinal herb and food additive licorice (Glycyrrhiza uralensis Fisch), has been indicated to possess potential anticancer effects and is widely utilized in hepatocellular carcinoma (HCC) targeted drug delivery systems (TDDS) due to the highly expressed target binding sites of GA on HCC cells. This study found that GA reduced the cell viability, increased the release of lactate dehydrogenase, and enhanced the expression of Bax, cleaved caspase-3, and LC3-II in HCC cells. The GA-triggered autophagy has been further confirmed by monodansylcadaverine staining as well as transmission electron microscopy analysis. The cell viability was obviously decreased whereas the expression of cleaved caspases was significantly increased when inhibition of autophagy by choloroquine or bafilomycin A1, suggesting that GA triggered a protective autophagy. Extracellular regulated protein kinase (ERK) was activated after treatment with GA in HepG2 cells and pretreatment with U0126 or PD98059, the MEK inhibitors, reversed GA-triggered autophagy as evidenced by decreased expression of LC3-II and formation of autophagosomes, respectively. Furthermore, GA-induced cell death and apoptosis were enhanced after pretreatment with PD98059. This is the first report that GA triggers a protective autophagy in HCC cells via activation of ERK, which might attenuate the anticancer effects of GA or chemotherapeutic drugs loaded with GA-modified TDDS.

Genomics in personalized cancer medicine and its impact on early drug development in China: report from the 6th Annual Meeting of the US Chinese Anti-Cancer Association (USCACA) at the 50th ASCO Annual Meeting.

The 6th Annual Meeting of the United States Chinese Anti-Cancer Association (USCACA) was held in conjunction with the 50th Annual Meeting of American Society of Clinical Oncology (ASCO) on May 30, 2014 in Chicago, Illinois, the United States of America. With a focus on personalized medicine, the conference featured novel approaches to investigate genomic aberrations in cancer cells and innovative clinical trial designs to expedite cancer drug development in biomarker-defined patient populations. A panel discussion further provided in-depth advice on advancing development of personalized cancer medicines in China. The conference also summarized USCACA key initiatives and accomplishments, including two awards designated to recognize young investigators from China for their achievements and to support their training in the United States. As an effort to promote international collaboration, USCACA will team up with Chinese Society of Clinical Oncology (CSCO) to host a joint session on "Breakthrough Cancer Medicines" at the upcoming CSCO Annual Meeting on September 20th, 2014 in Xiamen, China.

DJ-1 mediates the resistance of cancer cells to dihydroartemisinin through reactive oxygen species removal.

Dihydroartemisinin (DHA), one of the main metabolites of artemisinin and its derivatives, presents anti-cancer potential in vitro and in vivo. To explore the mechanisms of resistance toward DHA, a DHA-resistant cell line, HeLa/DHA, was established with a resistance factor of 7.26 in vitro. Upon DHA treatment, apoptotic cells were significantly elicited in parental HeLa cells but minimally induced in HeLa/DHA cells. HeLa/DHA cells also displayed much less sensitivity to DHA-induced tumor suppression in cancer xenograft models than HeLa cells. Intriguingly, DHA-resistant cells did not display a multidrug-resistant phenotype. Based on a proteomic study employing LC-ESI-MS/MS together with pathway analysis, DJ-1 (PARK7) was found to be highly expressed in HeLa/DHA cells. Western blot and immunofluorescence assays confirmed the higher expression of DJ-1 in HeLa/DHA cells than in parental cells in both cell line and xenograft models. DJ-1 is translocated to the mitochondria of HeLa/DHA cells and oxidized, providing DJ-1 with stronger cytoprotection activity. Further study revealed that DJ-1 knockdown in HeLa/DHA cells abolished the observed resistance, whereas overexpression of DJ-1 endowed the parental HeLa cells with resistance toward DHA. Reactive oxygen species (ROS) were also significantly induced by either DHA or hydrogen peroxide in HeLa cells but not in resistant HeLa/DHA cells. When the cells were pretreated with N-acetyl-l-cysteine, the effect of DJ-1 knockdown on sensitizing HeLa/DHA cells to DHA was significantly attenuated. In summary, our study suggests that overexpression and mitochondrial translocation of DJ-1 provides HeLa/DHA cells with resistance to DHA-induced ROS and apoptosis.

A collagen-remodeling gene signature regulated by TGF-ß signaling is associated with metastasis and poor survival in serous ovarian cancer.

PURPOSE: To elucidate molecular pathways contributing to metastatic cancer progression and poor clinical outcome in serous ovarian cancer. EXPERIMENTAL DESIGN: Poor survival signatures from three different serous ovarian cancer datasets were compared and a common set of genes was identified. The predictive value of this gene signature was validated in independent datasets. The expression of the signature genes was evaluated in primary, metastatic, and/or recurrent cancers using quantitative PCR and in situ hybridization. Alterations in gene expression by TGF-ß1 and functional consequences of loss of COL11A1 were evaluated using pharmacologic and knockdown approaches, respectively. RESULTS: We identified and validated a 10-gene signature (AEBP1, COL11A1, COL5A1, COL6A2, LOX, POSTN, SNAI2, THBS2, TIMP3, and VCAN) that is associated with poor overall survival (OS) in patients with high-grade serous ovarian cancer. The signature genes encode extracellular matrix proteins involved in collagen remodeling. Expression of the signature genes is regulated by TGF-ß1 signaling and is enriched in metastases in comparison with primary ovarian tumors. We demonstrate that levels of COL11A1, one of the signature genes, continuously increase during ovarian cancer disease progression, with the highest expression in recurrent metastases. Knockdown of COL11A1 decreases in vitro cell migration, invasion, and tumor progression in mice. CONCLUSION: Our findings suggest that collagen-remodeling genes regulated by TGF-ß1 signaling promote metastasis and contribute to poor OS in patients with serous ovarian cancer. Our 10-gene signature has both predictive value and biologic relevance and thus may be useful as a therapeutic target.

Genomic characterization of human and rat prolactinomas.

Although prolactinomas can be effectively treated with dopamine agonists, about 20% of patients develop dopamine resistance or tumor recurrence after surgery, indicating a need for better understanding of underlying disease mechanisms. Although estrogen-induced rat prolactinomas have been widely used to investigate the development of this tumor, the extent that the model recapitulates features of human prolactinomas is unclear. To prioritize candidate genes and gene sets regulating human and rat prolactinomas, microarray results derived from human prolactinomas and pituitaries of estrogen-treated ACI rats were integrated and analyzed. A total of 4545 differentially expressed pituitary genes were identified in estrogen-treated ACI rats [false discovery rate (FDR) < 0.01]. By comparing pituitary microarray results derived from estrogen-treated Brown Norway rats (a strain not sensitive to estrogen), 4073 genes were shown specific to estrogen-treated ACI rats. Human prolactinomas exhibited 1177 differentially expressed genes (FDR < 0.05). Combining microarray data derived from human prolactinoma and pituitaries of estrogen-treated ACI rat, 145 concordantly expressed genes, including E2F1, Myc, Igf1, and CEBPD, were identified. Gene set enrichment analysis revealed that 278 curated pathways and 59 gene sets of transcription factors were enriched (FDR < 25%) in estrogen-treated ACI rats, suggesting a critical role for Myc, E2F1, CEBPD, and Sp1 in this rat prolactinoma. Similarly increased Myc, E2F1, and Sp1 expression was validated using real-time PCR and Western blot in estrogen-treated Fischer rat pituitary glands. In summary, characterization of individual genes and gene sets in human and in estrogen-induced rat prolactinomas validates the model and provides insights into genomic changes associated with this commonly encountered pituitary tumor.

CEBPD suppresses prolactin expression and prolactinoma cell proliferation.

Hyperprolactinemia, usually caused by a pituitary lactotroph tumor, leads to galactorrhea and infertility. Increased prolactin (PRL) levels may be due to enhanced PRL expression or proliferation of PRL-secreting cells. We hypothesize that PRL expression and PRL-secreting cell proliferation are linked. Using microarray-based gene expression profiling, we identified CCAAT-enhancer-binding protein δ (CEBPD) transcription factor as a critical gene that regulates both PRL expression and lactotroph cell proliferation. CEBPD expression levels are decreased approximately 7-fold in experimental rat prolactinoma cells. Forced expression of this transcription factor in PRL-secreting cells (GH3 and MMQ) inhibited PRL expression and cellular proliferation, and CEBPD knockdown by small interfering RNA leads to increased PRL expression in both cell lines. To determine mechanisms underlying this observation, we determined binding of CEBPD to the PRL promoter and also showed marked suppression (96%) of PRL promoter activity. CEBPD and Pit1 interact and attenuate each other's binding to the PRL promoter. CEBPD also suppresses expression of proliferation-related genes, including c-Myc, survivin, as well as cyclins B1, B2, and D1. These results show that PRL expression and cell proliferation are controlled in part by CEBPD.

PTTG1 attenuates drug-induced cellular senescence.

As PTTG1 (pituitary tumor transforming gene) abundance correlates with adverse outcomes in cancer treatment, we determined mechanisms underlying this observation by assessing the role of PTTG1 in regulating cell response to anti-neoplastic drugs. HCT116 cells devoid of PTTG1 (PTTG1(-/-)) exhibited enhanced drug sensitivity as assessed by measuring BrdU incorporation in vitro. Apoptosis, mitosis catastrophe or DNA damage were not detected, but features of senescence were observed using low doses of doxorubicin and TSA. The number of drug-induced PTTG1(-/-) senescent cells increased ∼4 fold as compared to WT PTTG1-replete cells (p<0.001). p21, an important regulator of cell senescence, was induced ∼3 fold in HCT116 PTTG1(-/-) cells upon doxorubicin or Trichostatin A treatment. Binding of Sp1, p53 and p300 to the p21 promoter was enhanced in PTTG1(-/-) cells after treatment, suggesting transcriptional regulation of p21. p21 knock down abrogated the observed senescent effects of these drugs, indicating that PTTG1 likely suppresses p21 to regulate drug-induced senescence. PTTG1 also regulated SW620 colon cancer cells response to doxorubicin and TSA mediated by p21. Subcutaneously xenografted PTTG1(-/-) HCT116 cells developed smaller tumors and exhibited enhanced responses to doxorubicin. PTTG1(-/-) tumor tissue derived from excised tumors exhibited increased doxorubicin-induced senescence. As senescence is a determinant of cell responses to anti-neoplastic treatments, these findings suggest PTTG1 as a tumor cell marker to predict anti-neoplastic treatment outcomes.

Mouse models of colorectal cancer.

Colorectal cancer is one of the most common malignancies in the world. Many mouse models have been developed to evaluate features of colorectal cancer in humans. These can be grouped into genetically-engineered, chemically-induced, and inoculated models. However, none recapitulates all of the characteristics of human colorectal cancer. It is critical to use a specific mouse model to address a particular research question. Here, we review commonly used mouse models for human colorectal cancer.

Lineage-specific restraint of pituitary gonadotroph cell adenoma growth.

Although pituitary adenomas are usually benign, unique trophic mechanisms restraining cell proliferation are unclear. As GH-secreting adenomas are associated with p53/p21-dependent senescence, we tested mechanisms constraining non-functioning pituitary adenoma growth. Thirty six gonadotroph-derived non-functioning pituitary adenomas all exhibited DNA damage, but undetectable p21 expression. However, these adenomas all expressed p16, and >90% abundantly expressed cytoplasmic clusterin associated with induction of the Cdk inhibitor p15 in 70% of gonadotroph and in 26% of somatotroph lineage adenomas (p  =  0.006). Murine LßT2 and αT3 gonadotroph pituitary cells, and αGSU.PTTG transgenic mice with targeted gonadotroph cell adenomas also abundantly expressed clusterin and exhibited features of oncogene-induced senescence as evidenced by C/EBPß and C/EBPδ induction. In turn, C/EBPs activated the clusterin promoter ∼5 fold, and elevated clusterin subsequently elicited p15 and p16 expression, acting to arrest murine gonadotroph cell proliferation. In contrast, specific clusterin suppression by RNAis enhanced gonadotroph proliferation. FOXL2, a tissue-specific gonadotroph lineage factor, also induced the clusterin promoter ∼3 fold in αT3 pituitary cells. As nine of 12 pituitary carcinomas were devoid of clusterin expression, this protein may limit proliferation of benign adenomatous pituitary cells. These results point to lineage-specific pathways restricting uncontrolled murine and human pituitary gonadotroph adenoma cell growth.