Chaperonin-containing TCP-1 Research Articles

Increased CCT5 expression is a potential unfavourable factor promoting the growth of nasopharyngeal carcinoma.

Chaperonin containing TCP1 subunit 5 (CCT5) encodes the CCT5 protein subunit of chaperonin-containing TCP-1 (CCT/TRiC) complex, and is shown to be upregulated in tumour pathogenesis. The study aim was to investigate the differential expression of CCT5 between nasopharyngeal carcinoma (NPC) and noncancerous nasopharyngeal tissues, and the correlation between CCT5 expression and clinicopathological parameters/prognosis in patients with NPC. Microarray assay data were evaluated for differential expression between NPC and noncancerous nasopharyngeal tissues. CCT5 expression in NPC and noncancerous nasopharyngeal tissues was determined at mRNA and protein levels by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. Relationships between CCT5 expression in NPC, clinical parameters, and prognosis were statistically analysed. CCT5-mediated cell proliferation was assessed using EdU and cell counting kit-8. Western blot and co-immunoprecipitation were utilized to explore E3 ubiquitin-protein ligase parkin (PARK2)-induced degradation of CCT5. Microarray data showed CCT5 levels to be significantly increased in NPC versus noncancerous nasopharyngeal tissues, which was confirmed by qRT-PCR and immunohistochemical assays. Increased CCT5 protein levels positively correlated with tumour size, tumour recurrence, and clinical stage, and inversely correlated with patient's overall survival. Multivariate Cox regression analysis showed that enhanced CCT5 protein expression is an independent prognostic factor for patients with NPC. Overexpression of CCT5 markedly induced NPC cell proliferation. Finally, PARK2, as a suppressive E3 ubiquitin-ligase enzyme, was shown to bind CCT5 and induce degradation in NPC. Increased CCT5 may be an unfavourable factor promoting NPC growth. Binding of PARK2 to CCT5 was associated with CCT5 degradation, suggesting that PARK2 is an upstream negative modulator in NPC.

CCT3/ACTN4/TFRC axis protects hepatocellular carcinoma cells from ferroptosis by inhibiting iron endocytosis

Sorafenib is widely used in treating advanced hepatocellular carcinoma (HCC). However, its effectiveness in prolonging patient survival is limited by the development of drug resistance. To systematically investigate the resistance mechanisms of Sorafenib, an integrative analysis combining posttranslational modification (PTM) omics and CRISPR/Cas9 knockout library screening was conducted. This analysis identified ubiquitination at lysine 21 (K21) on chaperonin-containing TCP1 subunit 3 (CCT3) as being associated with Sorafenib resistance. Transcriptomic data from HCC patients treated with Sorafenib revealed that CCT3 expression was lower in responders compared to non-responders. Experimentally, inhibiting the expression of CCT3 sensitized HCC cells to Sorafenib and enhanced Sorafenib-induced ferroptosis. Additionally, CCT3 was found to interact with ACTN4, hindering the recycling of transferrin receptor protein 1 (TFRC) to the cell membrane, thus obstructing iron endocytosis. Mechanistically, the inhibition of ferroptosis by CCT3 depends on the deubiquitination of K6-linked non-degradative ubiquitination at its K21, which occurs upon Sorafenib treatment. Moreover, CCT3 knockdown enhanced the anti-tumor effects of Sorafenib in nude mice. In summary, we have identified a novel function of the chaperone protein. Targeting the CCT3/ACTN4/TFRC axis offers a promising strategy to enhance ferroptosis and overcome Sorafenib resistance in HCC.

CCT6A promotes cell proliferation in colon cancer by targeting BIRC5 associated with p53 status.

Chaperonin-containing TCP1 (CCT) is a multi-subunit complex, known to participate the correct folding of many proteins. Currently, the mechanism underlying CCT subunits in cancer progression is incompletely understood. Based on data analysis, the expression of CCT subunit 6 A (CCT6A) is found higher than the other subunits of CCT and correlated with an unfavorable prognosis in colon cancer. Here, we find CCT6A silencing suppresses colon cancer proliferation and survival phenotype in vitro and in vivo. CCT6A plays a role in cellular process, including the cell cycle, p53, and apoptosis signaling pathways. Further investigations have shown direct binding between CCT6A and both Wtp53 and Mutp53, and BIRC5 is found to act downstream of CCT6A. The highlight is that CCT6A inhibition significantly reduces BIRC5 expression independent of Wtp53 levels in Wtp53 cells. Conversely, in Mutp53 cells, downregulation of BIRC5 by CCT6A inhibition mainly depends on Mutp53 levels. Additionally, combined CCT6A inhibition and Wtp53 overexpression in Mutp53 cell lines effectively suppresses cell proliferation. It is concluded CCT6A is a potential oncogene that influences BIRC5 through distinct pathways in Wtp53 and Mutp53 cells.

Epsilon subunit of T-complex protein-1 from Leishmania donovani: A tetrameric chaperonin

The cytosolic T-complex protein-1 ring complex (TRiC), also referred as chaperonin containing TCP-1(CCT), comprising eight different subunits stacked in double toroidal rings, binds to around 10 % of newly synthesized polypeptides and facilitates their folding in ATP dependent manner. In Leishmania, among five subunits of TCP1 complex, identified either by transcriptome or by proteome analysis, only LdTCP1γ has been well characterized. It forms biologically active homo-oligomeric complex and plays role in protein folding and parasite survival. Lack of information regarding rest of the TCP1 subunits and its structural configuration laid down the necessity to study individual subunits and their role in parasite pathogenicity. The present study involves the cloning, expression and biochemical characterization of TCP1ε subunit (LdTCP1ε) of Leishmania donovani, the causative agent of visceral leishmaniasis. LdTCP1ε exhibited significant difference in primary structure as compared to LdTCP1γ and was evolutionary close to LdTCP1 zeta subunit. Recombinant protein (rLdTCP1ε) exhibited two major bands of 132 kDa and 240 kDa on native-PAGE that corresponds to the dimeric and tetrameric assembly of the epsilon subunit, which showed the chaperonin activity (ATPase and luciferase refolding activity). LdTCP1ε also displayed an increased expression upto 2.7- and 1.8-fold in the late log phase and stationary phase promastigotes and exhibited majorly vesicular localization. The study, thus for the first time, provides an insight for the presence of highly diverge but functionally active dimeric/tetrameric TCP1 epsilon subunit in Leishmania parasite.

Abstract 2747: Chaperonin-containing TCP-1 promotes the release of exosomes from prostate and breast cancer cells

Abstract Coping with cancer recurrence and assessing metastatic risk are challenges for cancer patients that could be addressed with an effective diagnostic predictor. Exosomes, a subpopulation of extracellular vesicles released by tumor cells, can promote distal metastatic site development and could have promising diagnostic applications. However, the mechanisms controlling exosome secretion by cancer cells remain to be determined, which impedes clinical development. The actions of protein-folding chaperones could facilitate tumor exosome formation, payload loading, and extracellular release. Protein folding complexes link the expression of tumor-promoting oncogenes with the proteins driving oncogenic cancer behavior. Of these, the eukaryotic type II chaperonin, Chaperonin-Containing TCP-1 (CCT), folds many of the oncoproteins (e.g., KRAS, MYC, CDKs, STAT3, etc.) responsible for cancer growth and invasion. CCT is a complex machine composed of eight subunits, each encoded by a unique gene (cct1-8), which folds proteins in an ATP-dependent fashion. We and others showed that CCT is upregulated in breast, lung, and prostate cancer cells as well as neuroblastoma, leading to alterations in apoptosis, migration, cell morphology, and proliferation. Using T47D breast cancer and PC3 and 22rV1 prostate cancer cells, we exogenously expressed or depleted the second subunit of the CCT complex (CCT2). With these cells, we isolated exosomes from culture media by membrane-based affinity binding and examined exosomal RNA and protein content. In exosomes from prostate and breast cancer cells, we found abundant CCT2 subunit mRNA and protein in CD63+ exosomes ranging from 50 to 120 microns in size. When CCT2 was exogenously expressed in breast and prostate cancer cells, CCT2 mRNA and protein were higher in exosomes than other CCT subunits, and CCT2 was randomly distributed throughout the size range of exosomes. Of interest, an increase in CD63+ small exosomes (50-75 microns) was evident in cancer cells exogenously expressing CCT2 compared to mock-transfected and parental controls, suggesting a role for CCT2 in the exosomal secretory pathway. FACS-sorted CD63+ exosomes subjected to mass spectrometry yielded distinct protein content based on CCT2 expression. These findings are the first report of CCT2 driving exosome secretion in cancer cells and suggest that exosomes containing CCT2 RNA and protein are associated with metastatic potential. Exosomal CCT2 thus represents a promising diagnostic indicator for a liquid biopsy approach to monitor cancer recurrence and metastasis. Citation Format: Annette R. Khaled, Lam Truong, Colten Frank, Carolyn Dang, James Velazquez, Priya Gopalan, Sally Litherland. Chaperonin-containing TCP-1 promotes the release of exosomes from prostate and breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2747.

The Chaperone Protein Cct5 is Essential for Hematopoietic Stem Cell Maintenance.

Proper proteostasis is indispensable for the long-term maintenance of hematopoietic stem and progenitor cells (HSPCs). The TRiC/CCT (chaperonin-containing TCP-1) complex, a key constituent of cellular machinery facilitating accurate protein folding, has remained enigmatic in its specific function within HSPCs. Here we show that conditional knockout (KO) of Cct5 significantly impairs the maintenance of murine HSPCs. Primary and secondary transplantation experiments unequivocally demonstrate the incapacity of Cct5 KO HSPCs to reconstitute both myeloid and lymphoid lineage cells in recipient mice, highlighting the pivotal role of the TRiC/CCT complex in governing these cellular lineages. Furthermore, leveraging an integrated approach that merges a Protein-Protein Interaction (PPI) database with RNA sequencing (RNA-seq) data of HSPCs, our analysis reveals intricate interactions between Cct5 and vital transcription factors crucial for HSC homeostasis. Notably, Cct5 engages with MYC, PIAS1, TP53, ESR1, HOXA1, and JUN, intricately regulating the transcriptional landscape governing autophagy, myeloid differentiation, and cytoskeleton organization within HSPCs. Our study unveils the profound significance of TRiC/CCT complex-mediated proteostasis in orchestrating the maintenance and functionality of HSPCs.

Loss of PMFBP1 Disturbs Mouse Spermatogenesis by Downregulating HDAC3 Expression.

Polyamine modulating factor 1 binding protein (PMFBP1) acts as a scaffold protein for the maintenance of sperm structure. The aim of this study was further to identify the new role and molecular mechanism of PMFBP1 during mouse spermatogenesis. We identified a profile of proteins interacting with PMFBP1 by immunoprecipitation combined with mass spectrometry and demonstrated that class I histone deacetylases, particularly HDAC3 and chaperonin-containing TCP1 subunit 3 (CCT3), were potential interaction partners of PMFBP1 based on network analysis of protein-protein interactions and co-immunoprecipitation. Immunoblotting and immunochemistry assays showed that loss of Pmfbp1 would result in a decline in HDACs and change the proteomic profile of mouse testis, in which differently expressed proteins are associated with spermatogenesis and assembly of flagella, which was proved by proteomic analysis of testis tissue obtained from Pmfbp1-/- mice. After integrating with transcriptome data for Hdac3-/- and Sox30-/- round sperm obtained from a public database, RT-qPCR confirmed ring finger protein 151 (Rnf151) and ring finger protein 133 (Rnf133) were key downstream response factors of the Pmfbp1-Hdac axis affecting mouse spermatogenesis. Taken together, this study indicates a previously unidentified molecular mechanism of PMFBP1 in spermatogenesis whereby PMFBP1 interacts with CCT3, affecting the expression of HDAC3, followed by the downregulation of RNF151 and RNF133, resulting in an abnormal phenotype of sperm beyond the headless sperm tails. These findings not only advance our understanding of the function of Pmfbp1 in mouse spermatogenesis but also provide a typical case for multi-omics analysis used in the functional annotation of specific genes.

Multi-Omics Analysis and Verification of the Oncogenic Value of CCT8 in Pan-Cancers.

Chaperonin-containing TCP1 subunit 8 (CCT8) has been proved to be involved in the occurrence and development of some cancers. However, no study has reported the potential role of CCT8 in a pan-cancer manner. TIMER2.0, GEPIA2, UALCAN and Sangerbox were used to explore the expression, prognosis and methylation of CCT8. We used cBioPortal, TISIDB, SangerBox, TIMER2.0 and TISMO to investigate the genetic alteration of CCT8 and the relationship of CCT8 with molecular subtype, immune subtype, immune infiltration and immunotherapy response. CCT8-related genes were screened out through GEPIA and STRING for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. CCK-8, the colony formation assay, the wound healing assay and the Transwell assay were performed to explore the influence of CCT8 on proliferation and migration. CCT8 was highly expressed in most cancers with a poor prognosis. The expression level of CCT8, which was affected by the promoter region methylation and genetic alteration, was related to the molecular and immune subtype of cancers. Interestingly, CCT8 was positively associated with the activated CD4 T cells and type 2 T-helper cells. CCT8 played a vital role in the cell cycle and RNA transport of cancers, and it significantly inhibited the proliferation and migration of lung adenocarcinoma cells when it was knocked down. CCT8 plays an indispensable role in promoting the proliferation and migration of many cancers. CCT8 might be a biomarker of T-helper type 2 (Th2) cell infiltration and a promising therapeutic target for T-helper type 1(Th1)/Th2 imbalance.

CCT6A promotes esophageal squamous cell carcinoma cell proliferation, invasion and epithelial-mesenchymal transition by activating TGF-β/Smad/c-Myc pathway.

Chaperonin-containing TCP1 subunit 6A (CCT6A) facilitates several malignant cancer behaviors, but its regulation of esophageal squamous cell carcinoma (ESCC) has not been reported. This study aimed to investigate the effect of CCT6A on cell proliferation, apoptosis, invasion and epithelial-mesenchymal transition (EMT) and its interaction with the TGF-β/Smad/c-Myc pathway in ESCC. CCT6A expression was detected in ESCC and normal esophageal epithelial cell lines by RT‒qPCR and western blotting. Furthermore, CCT6A siRNA, negative control (NC) siRNA, CCT6A encoding plasmid and NC encoding plasmid were transfected into OE21 and TE-1 cells. Subsequently, CCT6A siRNA- and NC siRNA-transfected cells were treated with TGF-β for rescue experiments. Cell proliferation, apoptosis, invasion, and E-cadherin/N-cadherin and p-Smad2/p-Smad3/c-Myc expression were detected. CCT6A expression was increased in KYSE-180, TE-1, TE-4 and OE21 cells compared with HET-1A cells. In both OE21 and TE-1 cells, CCT6A knockdown inhibited cell proliferation, invasion and N-cadherin expression while promoting cell apoptosis and E-cadherin expression; meanwhile, CCT6A overexpression had the opposite effects. Furthermore, in both OE21 and TE-1 cells, CCT6A knockdown decreased p-Smad2/Smad2, p-Smad3/Smad3 and c-Myc/GAPDH expression; CCT6A overexpression had the opposite effects. Next, TGF-β facilitated cell proliferation, invasion, and N-cadherin, p-Smad2/Smad2, p-Smad3/Smad2 and c-Myc/GAPDH expression while repressing cell apoptosis and E-cadherin expression in OE21 and TE-1 cells; importantly, TGF-β could compensate for the regulation of CCT6A knockdown on these activities. CCT6A facilitates ESCC malignant activities by activating the TGF-β/Smad/c-Myc pathway, which sheds light on the identification of a possible therapeutic target in the management of ESCC.

Maize tubulin folding cofactor B is required for cell division and cell growth through modulating microtubule homeostasis.

Tubulin folding cofactors (TFCs) are required for tubulin folding, α/β tubulin heterodimer formation, and microtubule (MT) dynamics in yeast and mammals. However, the functions of their plant counterparts remain to be characterized. We identified a natural maize crumpled kernel mutant, crk2, which exhibits reductions in endosperm cell number and size, as well as embryo/seedling lethality. Map-based cloning and functional complementation confirmed that ZmTFCB is causal for the mutation. ZmTFCB is targeted mainly to the cytosol. It facilitates α-tubulin folding and heterodimer formation through sequential interactions with the cytosolic chaperonin-containing TCP-1 ε subunit ZmCCT5 and ZmTFCE, thus affecting the organization of both the spindle and phragmoplast MT array and the cortical MT polymerization and array formation, which consequently mediated cell division and cell growth. We detected a physical association between ZmTFCB and the maize MT plus-end binding protein END-BINDING1 (ZmEB1), indicating that ZmTFCB1 may modulate MT dynamics by sequestering ZmEB1. Our data demonstrate that ZmTFCB is required for cell division and cell growth through modulating MT homeostasis, an evolutionarily conserved machinery with some species-specific divergence.

Phosducin-like 3 is a novel prognostic and onco-immunological biomarker in glioma: A multi-omics analysis with experimental verification.

Malignant glioma is the most frequent primary tumor of the central nervous system. PDCL3 is a member of the phosducin-like protein family, and its imbalance has been shown to be associated with several human diseases. However, the underlying role of PDCL3 in human malignant cancers, especially in malignant gliomas, is unclear. In this study, we combined public database analysis and experimental verification to explore the differential expression, prognostic value and potential functions and mechanisms of PDCL3. The results revealed that PDCL3 is upregulated in multiple cancers and acts as a potential prognostic biomarker of glioma. Mechanistically, PDCL3 expression is associated with epigenetic modifications and genetic mutations. PDCL3 may directly interact with the chaperonin-containing TCP1 complex, regulating cell malignancy, cell communication and the extracellular matrix. More importantly, the association of PDCL3 with the infiltration of immune cells, immunomodulatory genes, immune checkpoints, cancer stemness and angiogenesis suggested that PDCL3 may regulate the glioma immune landscape. Furthermore, PDCL3 interference also decreased the proliferation, invasion and migration of glioma cells. In conclusion, PDCL3 is a novel oncogene and can be adopted as a biomarker with value in assisting clinical diagnosis, predicting patient outcomes and assessing the immune landscape of the tumor microenvironment in glioma.

Structural and Dynamic Disturbances Revealed by Molecular Dynamics Simulations Predict the Impact on Function of CCT5 Chaperonin Mutations Associated with Rare Severe Distal Neuropathies

Mutations in genes encoding molecular chaperones, for instance the genes encoding the subunits of the chaperonin CCT (chaperonin containing TCP-1, also known as TRiC), are associated with rare neurodegenerative disorders. Using a classical molecular dynamics approach, we investigated the occurrence of conformational changes and differences in physicochemical properties of the CCT5 mutations His147Arg and Leu224Val associated with a sensory and a motor distal neuropathy, respectively. The apical domain of both variants was substantially but differently affected by the mutations, although these were in other domains. The distribution of hydrogen bonds and electrostatic potentials on the surface of the mutant subunits differed from the wild-type molecule. Structural and dynamic analyses, together with our previous experimental data, suggest that genetic mutations may cause different changes in the protein-binding capacity of CCT5 variants, presumably within both hetero- and/or homo-oligomeric complexes. Further investigations are necessary to elucidate the molecular pathogenic pathways of the two variants that produce the two distinct phenotypes. The data and clinical observations by us and others indicate that CCT chaperonopathies are more frequent than currently believed and should be investigated in patients with neuropathies.

Superenhancer activation of KLHDC8A drives glioma ciliation and hedgehog signaling.

Glioblastoma ranks among the most aggressive and lethal of all human cancers. Self-renewing, highly tumorigenic glioblastoma stem cells (GSCs) contribute to therapeutic resistance and maintain cellular heterogeneity. Here, we interrogated superenhancer landscapes of primary glioblastoma specimens and patient-derived GSCs, revealing a kelch domain-containing gene, specifically Kelch domain containing 8A (KLHDC8A) with a previously unknown function as an epigenetically driven oncogene. Targeting KLHDC8A decreased GSC proliferation and self-renewal, induced apoptosis, and impaired in vivo tumor growth. Transcription factor control circuitry analyses revealed that the master transcriptional regulator SOX2 stimulated KLHDC8A expression. Mechanistically, KLHDC8A bound chaperonin-containing TCP1 (CCT) to promote the assembly of primary cilia to activate hedgehog signaling. KLHDC8A expression correlated with Aurora B/C Kinase inhibitor activity, which induced primary cilia and hedgehog signaling. Combinatorial targeting of Aurora B/C kinase and hedgehog displayed augmented benefit against GSC proliferation. Collectively, superenhancer-based discovery revealed KLHDC8A as what we believe to be a novel molecular target of cancer stem cells that promotes ciliogenesis to activate the hedgehog pathway, offering insights into therapeutic vulnerabilities for glioblastoma treatment.

CCT3 as a Diagnostic and Prognostic Biomarker in Cervical Cancer.

The chaperonin-containing TCP1 complex subunit 3 (CCT3) has been reported to be involved in the development and prognosis of many tumors, including cervical cancer (CC). This study aimed to analyze the expression and prognostic value of CCT3 in CC by bioinformatics and retrospective study. CCT3 gene expression profiles and clinical information in CC were downloaded from the cancer genome atlas (TCGA) and gene expression omnibus (GEO) databases. CCT3 expression was verified by quantitative real-time polymerase chain reaction (RT-qPCR), Western blot, and immunohistochemistry (IHC). Logistic regression and chi-square testing were used to analyze the relationship between CCT3 expression and the clinical characteristics of CC. Kaplan-Meier and Cox analyses were used to evaluate whether CCT3 affects the prognosis of CC. Nomogram and calibration curves were used to test the predictive value of CCT3. The expression of CCT3 in CC tissues was significantly upregulated compared with that in adjacent benign tissues, and was related to HPV16/18 infection, grade, and positive lymph nodes. High expression of CCT3 is associated with poor prognosis of CC and can be used as an independent risk factor for CC. The prognostic model based on CCT3 and CC clinical features has good predictive ability. CCT3 is overexpressed in CC, which is related to poor prognosis and expected to become a biomarker for CC.

CCT6A knockdown suppresses osteosarcoma cell growth and Akt pathway activation in vitro.

We assessed the role of the protein-coding gene chaperonin-containing TCP1 subunit 6A (CCT6A) in osteosarcoma, as this is currently unknown. Using data from the R2 online genomic analysis and visualization application, we found that CCT6A messenger ribonucleic acid (RNA) expression is increased in osteosarcoma tissue and cells. Transfection of CCT6A small interfering RNA into cultured osteosarcoma cells revealed that CCT6A knockdown attenuates cell growth, cell viability, cell survival, and induced apoptosis and cell cycle progression at the G0/G1 phases. Moreover, CCT6A knockdown downregulated phospho-protein kinase B (p-Akt), cyclinD1 and B-cell lymphoma-2, whereas upregulated Bcl-2-associated X-protein expression. Thus, CCT6A knockdown inhibits cell proliferation, induces cell apoptosis, and suppresses the Akt pathway.

The malaria parasite chaperonin containing TCP-1 (CCT) complex: Data integration with other CCT proteomes.

The multi-subunit chaperonin containing TCP-1 (CCT) is an essential molecular chaperone that functions in the folding of key cellular proteins. This paper reviews the interactome of the eukaryotic chaperonin CCT and its primary clients, the ubiquitous cytoskeletal proteins, actin and tubulin. CCT interacts with other nascent proteins, especially the WD40 propeller proteins, and also assists in the assembly of several protein complexes. A new proteomic dataset is presented for CCT purified from the human malarial parasite, P. falciparum (PfCCT). The CCT8 subunit gene was C-terminally FLAG-tagged using Selection Linked Integration (SLI) and CCT complexes were extracted from infected human erythrocyte cultures synchronized for maximum expression levels of CCT at the trophozoite stage of the parasite's asexual life cycle. We analyze the new PfCCT proteome and incorporate it into our existing model of the CCT system, supported by accumulated data from biochemical and cell biological experiments in many eukaryotic species. Together with measurements of CCT mRNA, CCT protein subunit copy number and the post-translational and chemical modifications of the CCT subunits themselves, a cumulative picture is emerging of an essential molecular chaperone system sitting at the heart of eukaryotic cell growth control and cell cycle regulation.

Abstract B026: Expression levels of chaperonin containing TCP1 in cancer are among the highest in sarcomas

Abstract Protein folding complexes are essential for oncogenesis. Of these, the multi-subunit complex, Chaperonin-Containing TCP-1 (CCT or TRiC), is upregulated across a spectrum of cancers and folds many of the oncoproteins that drive cancer growth. Using the UCSC Xena online database, which includes datasets from TCGA, TARGET, GTEx, and KidsFirst, we found significant increases in gene expression of the subunits (CCT1-8) that form the chaperonin complex in sarcomas, both adult and pediatric, as compared to other cancers like invasive breast carcinoma, lung carcinoma, glioblastoma multiforme, or prostate cancer. Most notably was the high expression of the second subunit (CCT2) in Rhabdomyosarcoma compared to other pediatric cancers. These findings were confirmed with other databases (e.g., Oncomine). Expression of CCT subunits, like CCT2, was decreased in normal tissues, such as muscle, kidney, and uterus, as compared to sarcoma tissues. Bioinformatic data was confirmed by finding detectable staining of CCT2 protein in sarcoma tissues. This was supported by data from the human protein atlas showing minimal staining for CCT2 in normal smooth and skeletal muscle. Cancer adjacent tissues from a metastatic breast cancer patient study had minimal staining for CCT2 in muscle, fat, and bone. These data show that CCT is increased in sarcomas, while decreased in normal tissues, and has potential for further study as a driver of sarcoma development and a target for therapeutic intervention. Citation Format: Amanda J. Cox, Annette Khaled. Expression levels of chaperonin containing TCP1 in cancer are among the highest in sarcomas [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr B026.

Chaperonin-containing TCP-1 subunit 2-mediated aggrephagy: A potential target for treating neurodegeneration.

Chaperonin-containing TCP-1 subunit 2-mediated aggrephagy: A potential target for treating neurodegeneration.

Chaperonin containing TCP1 as a marker for identification of circulating tumor cells in blood

Herein we report the use of Chaperonin-Containing TCP-1 (CCT or TRiC) as a marker to detect circulating tumor cells (CTCs) that are shed from tumors during oncogenesis. Most detection methods used in liquid biopsy approaches for enumeration of CTCs from blood, employ epithelial markers like cytokeratin (CK). However, such markers provide little information on the potential of these shed tumor cells, which are normally short-lived, to seed metastatic sites. To identify a marker that could go beyond enumeration and provide actionable data on CTCs, we evaluated CCT. CCT is a protein-folding complex composed of eight subunits. Previously, we found that expression of the second subunit (CCT2 or CCTβ) inversely correlated with cancer patient survival and was essential for tumorigenesis in mice, driving tumor-promoting processes like proliferation and anchorage-independent growth. In this study, we examined CCT2 expression in cancer compared to normal tissues and found statistically significant increases in tumors. Because not all blood samples from cancer patients contain detectable CTCs, we used the approach of spiking a known number of cancer cells into blood from healthy donors to test a liquid biopsy approach using CCT2 to distinguish rare cancer cells from the large number of non-cancer cells in blood. Using a clinically validated method for capturing CTCs, we evaluated detection of intracellular CCT2 staining for visualization of breast cancer and small cell lung (SCLC) cancer cells. We demonstrated that CCT2 staining could be incorporated into a CTC capture and staining protocol, providing biologically relevant information to improve detection of cancer cells shed in blood. These results were confirmed with a pilot study of blood from SCLC patients. Our studies demonstrate that detection of CCT2 could identify rare cancer cells in blood and has application in liquid biopsy approaches to enhance the use of minimally invasive methods for cancer diagnosis.

The TRiCky Business of Protein Folding in Health and Disease.

Maintenance of the cellular proteome or proteostasis is an essential process that when deregulated leads to diseases like neurological disorders and cancer. Central to proteostasis are the molecular chaperones that fold proteins into functional 3-dimensional (3D) shapes and prevent protein aggregation. Chaperonins, a family of chaperones found in all lineages of organisms, are efficient machines that fold proteins within central cavities. The eukaryotic Chaperonin Containing TCP1 (CCT), also known as Tailless complex polypeptide 1 (TCP-1) Ring Complex (TRiC), is a multi-subunit molecular complex that folds the obligate substrates, actin, and tubulin. But more than folding cytoskeletal proteins, CCT differs from most chaperones in its ability to fold proteins larger than its central folding chamber and in a sequential manner that enables it to tackle proteins with complex topologies or very large proteins and complexes. Unique features of CCT include an asymmetry of charges and ATP affinities across the eight subunits that form the hetero-oligomeric complex. Variable substrate binding capacities endow CCT with a plasticity that developed as the chaperonin evolved with eukaryotes and acquired functional capacity in the densely packed intracellular environment. Given the decades of discovery on the structure and function of CCT, much remains unknown such as the scope of its interactome. New findings on the role of CCT in disease, and potential for diagnostic and therapeutic uses, heighten the need to better understand the function of this essential molecular chaperone. Clues as to how CCT causes cancer or neurological disorders lie in the early studies of the chaperonin that form a foundational knowledgebase. In this review, we span the decades of CCT discoveries to provide critical context to the continued research on the diverse capacities in health and disease of this essential protein-folding complex.