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Prostate cancer is the most common noncutaneous cancer among men in the United States. A genetic contribution to prostate cancer risk has been documented, but knowledge of the molecular mechanisms involved in prostate cancer initiation is still not well understood. Loss of heterozygosity (LOH) of chromosomal regions is crucial in tumor progression. In human prostate cancer, several chromosomal regions demonstrating a high frequency of LOH have been previously identified. KCTD11 (REN) is a tumor suppressor gene mapping on human chromosome 17p13.2, whose expression is frequently lost in human medulloblastoma and in several other cancer types. KCTD11 acts as a negative regulator of the Hedgehog (Hh) signaling. Here, we demonstrated that KCTD11 LOH is a common genetic lesion in human prostate adenocarcinoma. Indeed, nuclear KCTD11 protein expression is strongly reduced in primary prostate cancer, and this event correlated with overexpression of proteins acting into the Hedgehog pathway. Low levels of KCTD11 mRNA have been also observed in prostatic cancer cells, and ectopic overexpression of KCTD11 led to growth arrest. Our study demonstrates and supports that KCTD11, as well as negatively regulated downstreameffectors belonging to Hh signaling, plays a role in prostate cancer pathogenesis. This could be suitable to characterize new diagnostic and therapeutic markers. [ABSTRACT FROM AUTHOR]

The Ikaros gene encodes a Krüppel-like zinc-finger transcription factor involved in hematopoiesis regulation. Ikaros has been established as one of the most clinically relevant tumor suppressors in several hematological malignancies. In fact, expression of dominant negative Ikaros isoforms is associated with adult B-cell acute lymphoblastic leukemia, myelodysplastic syndrome, acute myeloid leukemia and adult and juvenile chronic myeloid leukemia. Here, we report the isolation of a novel, non-canonical Ikaros splice variant, called Ikaros 11 (Ik11). Ik11 is structurally related to known dominant negative Ikaros isoforms, due to the lack of a functional DNA-binding domain. Interestingly, Ik11 is the first Ikaros splice variant missing the transcriptional activation domain. Indeed, we demonstrated that Ik11 works as a dominant negative protein, being able to dimerize with Ikaros DNA-binding isoforms and inhibit their functions, at least in part by retaining them in the cytoplasm. Notably, we demonstrated that Ik11 is the first dominant negative Ikaros isoform to be aberrantly expressed in B-cell lymphoproliferative disorders, such as chronic lymphocytic leukemia. Aberrant expression of Ik11 interferes with both proliferation and apoptotic pathways, providing a mechanism for Ik11 involvement in tumor pathogenesis. Thus, Ik11 could represent a novel marker for B-cell lymphoproliferative disorders. [ABSTRACT FROM AUTHOR]

A hallmark of several human cancers is loss of heterozygosity (LOH) of chromosome 17p13. The same chromosomal region is also frequently hypermethylated in cancer. Although loss of 17p13 has been often associated with p53 genetic alteration or Hypermethylated in Cancer 1 (HIC1) gene hypermethylation, other tumor suppressor genes (TSGs) located in this region have critical roles in tumorigenesis. A novel TSG mapping on human chromosome 17p13.2 is KCTD11REN (KCTD11). We have recently demonstrated that KCTD11 expression is frequently lost in human medulloblastoma (MB), in part by LOH and in part by uncharacterized epigenetic events. Using a panel of human 177 tumor samples and their normal matching samples representing 18 different types of cancer, we show here that the down-regulation of KCTD11 protein level is a specific and a diffusely common event in tumorigenesis. Additionally, in order to characterize the regulatory regions in KCTD11 promoter, we identified a CpG island and several Sp1 binding sites on this promoter, and demonstrated that Sp1 transcription factor and DNA methylation contribute, at least in part, to regulate KCTD11 expression. Our findings identify KCTD11 as a widely downregulated gene in human cancers, and provide a basis to understand how its expression might be deregulated in tumor cells. [ABSTRACT FROM AUTHOR]

Cell fractionation is a method used to study different cellular events like protein translocation and sequestration by disrupting cells and fractionating their contents, thus allowing an enrichment of the protein of interest. Using different concentrations of sucrose or detergent buffer formulations in combination with centrifugations, the cell fractions are separated based on their density and size.

Peptides are emerging as an increasingly dependable class of therapeutics in the treatment of cancer and metabolic and cardiovascular diseases, which are all areas of high interest to the pharmaceutical industry. The global market for peptide therapeutics was valued at about 25 billion USD in 2018 and is estimated to reach 57.2 billion USD by the end of 2027. Here, we describe a method for the screening and deconvolution of combinatorial peptide libraries to discover compounds that target discrete signaling components of the NF-κB pathway. Recently, we used this approach to specifically disrupt the interaction between the JNK-activating kinase, MKK7, and the NF-κB-regulated antiapoptotic factor, GADD45β, in multiple myeloma (MM). We showed that the GADD45β/MKK7 complex is a functionally critical survival module downstream of NF-κB in MM cells and as such provides an attractive therapeutic target to selectively inhibit NF-κB antiapoptotic signaling in cancer cells. By integrating the library screening and deconvolution methods described here with a rational chemical optimization strategy, we developed the first-in-class GADD45β/MKK7 inhibitor, DTP3 (a D-tripeptide), which is now being trialed in MM and diffuse large B-cell lymphoma (DLBCL) patients. The same drug discovery approach may be generally applied to therapeutically target other key components of the NF-κB pathway in cancers beyond MM and DLBCL, as well as in non-malignant NF-κB-driven diseases.

Immunohistochemistry (IHC) is a technique aimed at detecting specific antigens on tissue sections by the use of targeting reagents labeled with reporter molecules. This technique allows a snapshot of the structure of tissue and determines the cellular and subcellular localization of a target antigen. This chapter describes how to identify and localize NF-κB proteins in human tissue using immunohistochemical staining on formalin-fixed paraffin-embedded and frozen tissue.

The reprogramming of cell metabolism is a hallmark of cancer. NF-κB transcription factors coordinate the host defense responses to stress, injury, and infection. They also play a central role in oncogenesis, at least in part by regulating cell metabolism and the adaptation to energy stress conditions in various types of cancer, such as colorectal carcinoma (CRC). Here, we describe the XF Cell Mito Stress Test methodology aimed at characterizing the metabolic and bioenergetic profile of CRC cells following the silencing of the essential NF-κB subunit, RelA. This methodology may also be applied to other cancers to reveal novel core vulnerabilities of malignant cells.