Regulation of p53 and Cancer Signaling by Heat Shock Protein 40/J-Domain Protein Family Members

Recent Advances on Mutant p53: Unveiling Novel Oncogenic Roles, Degradation Pathways, and Therapeutic Interventions

The p53 protein is the master regulator of cellular integrity, primarily due to its tumor-suppressing functions. Approximately half of all human cancers carry mutations in the TP53 gene, which not only abrogate the tumor-suppressive functions but also confer p53 mutant proteins with oncogenic potential. The latter is achieved through so-called gain-of-function (GOF) mutations that promote cancer progression, metastasis, and therapy resistance by deregulating transcriptional networks, signaling pathways, metabolism, immune surveillance, and cellular compositions of the microenvironment. Despite recent progress in understanding the complexity of mutp53 in neoplastic development, the exact mechanisms of how mutp53 contributes to cancer development and how they escape proteasomal and lysosomal degradation remain only partially understood. In this review, we address recent findings in the field of oncogenic functions of mutp53 specifically regarding, but not limited to, its implications in metabolic pathways, the secretome of cancer cells, the cancer microenvironment, and the regulating scenarios of the aberrant proteasomal degradation. By analyzing proteasomal and lysosomal protein degradation, as well as its connection with autophagy, we propose new therapeutical approaches that aim to destabilize mutp53 proteins and deactivate its oncogenic functions, thereby providing a fundamental basis for further investigation and rational treatment approaches for TP53-mutated cancers.

Systems Biology for Drug Target Discovery in Acute Myeloid Leukemia

Combining new therapeutics with all-trans-retinoic acid (ATRA) could improve the efficiency of acute myeloid leukemia (AML) treatment. Modeling the process of ATRA-induced differentiation based on the transcriptomic profile of leukemic cells resulted in the identification of key targets that can be used to increase the therapeutic effect of ATRA. The genome-scale transcriptome analysis revealed the early molecular response to the ATRA treatment of HL-60 cells. In this study, we performed the transcriptomic profiling of HL-60, NB4, and K562 cells exposed to ATRA for 3-72 h. After treatment with ATRA for 3, 12, 24, and 72 h, we found 222, 391, 359, and 1032 differentially expressed genes (DEGs) in HL-60 cells, as well as 641, 1037, 1011, and 1499 DEGs in NB4 cells. We also found 538 and 119 DEGs in K562 cells treated with ATRA for 24 h and 72 h, respectively. Based on experimental transcriptomic data, we performed hierarchical modeling and determined cyclin-dependent kinase 6 (CDK6), tumor necrosis factor alpha (TNF-alpha), and transcriptional repressor CUX1 as the key regulators of the molecular response to the ATRA treatment in HL-60, NB4, and K562 cell lines, respectively. Mapping the data of TMT-based mass-spectrometric profiling on the modeling schemes, we determined CDK6 expression at the proteome level and its down-regulation at the transcriptome and proteome levels in cells treated with ATRA for 72 h. The combination of therapy with a CDK6 inhibitor (palbociclib) and ATRA (tretinoin) could be an alternative approach for the treatment of acute myeloid leukemia (AML).

A unique chaperoning mechanism in class A JDPs recognizes and stabilizes mutant p53

J-domain proteins (JDPs) constitute a large family of molecular chaperones that bind a broad spectrum of substrates, targeting them to Hsp70, thus determining the specificity of and activating the entire chaperone functional cycle. The malfunction of JDPs is therefore inextricably linked to myriad human disorders. Here, we uncover a unique mechanism by which chaperones recognize misfolded clients, present in human class A JDPs. Through a newly identified β-hairpin site, these chaperones detect changes in protein dynamics at the initial stages of misfolding, prior to exposure of hydrophobic regions or large structural rearrangements. The JDPs then sequester misfolding-prone proteins into large oligomeric assemblies, protecting them from aggregation. Through this mechanism, class A JDPs bind destabilized p53 mutants, preventing clearance of these oncoproteins by Hsp70-mediated degradation, thus promoting cancer progression. Removal of the β-hairpin abrogates this protective activity while minimally affecting other chaperoning functions. This suggests the class A JDP β-hairpin as a highly specific target for cancer therapeutics.

Prognosis value of heat-shock proteins in esophageal and esophagogastric cancer: A systematic review and meta-analysis

BACKGROUND

Heat shock proteins (HSPs) are molecular chaperones that play an important role in cellular protection against stress events and have been reported to be overexpressed in many cancers. The prognostic significance of HSPs and their regulatory factors, such as heat shock factor 1 (HSF1) and CHIP, are poorly understood.

AIM

To investigate the relationship between HSP expression and prognosis in esophageal and esophagogastric cancer.

METHODS

A systematic review was conducted in accordance with PRISMA recommendations (PROSPERO: CRD42022370653), on Embase, PubMed, Cochrane, and LILACS. Cohort, case-control, and cross-sectional studies of patients with esophagus or esophagogastric cancer were included. HSP-positive patients were compared with HSP-negative, and the endpoints analyzed were lymph node metastasis, tumor depth, distant metastasis, and overall survival (OS). HSPs were stratified according to the HSP family, and the summary risk difference (RD) was calculated using a random-effect model.

RESULTS

The final selection comprised 27 studies, including esophageal squamous cell carcinoma (21), esophagogastric adenocarcinoma (5), and mixed neoplasms (1). The pooled sample size was 3465 patients. HSP40 and 60 were associated with a higher 3-year OS [HSP40: RD = 0.22; 95% confidence interval (CI): 0.09-0.35; HSP60: RD = 0.33; 95%CI: 0.17-0.50], while HSF1 was associated with a poor 3-year OS (RD = -0.22; 95%CI: -0.32 to -0.12). The other HSP families were not associated with long-term survival. HSF1 was associated with a higher probability of lymph node metastasis (RD = -0.16; 95%CI: -0.29 to -0.04). HSP40 was associated with a lower probability of lymph node dissemination (RD = 0.18; 95%CI: 0.03-0.33). The expression of other HSP families was not significantly related to tumor depth and lymph node or distant metastasis.

CONCLUSION

The expression levels of certain families of HSP, such as HSP40 and 60 and HSF1, are associated with long-term survival and lymph node dissemination in patients with esophageal and esophagogastric cancer.

Enhancement of colorectal cancer therapy through interruption of the HSF1-HSP90 axis by p53 activation or cell cycle inhibition

The stress-associated molecular chaperone system is an actionable target in cancer therapies. It is ubiquitously upregulated in cancer tissues and enables tumorigenicity by stabilizing hundreds of oncoproteins and disturbing the stoichiometry of protein complexes. Most inhibitors target the key component heat-shock protein 90 (HSP90). However, although classical HSP90 inhibitors are highly tumor-selective, they fail in phase 3 clinical oncology trials. These failures are at least partly due to an interference with a negative feedback loop by HSP90 inhibition, known as heat-shock response (HSR): in response to HSP90 inhibition there is compensatory synthesis of stress-inducible chaperones, mediated by the transcription factor heat-shock factor 1 (HSF1). We recently identified that wildtype p53 (p53) actively reduces the HSR by repressing HSF1 via a p21-CDK4/6-MAPK-HSF1 axis. Here we test the hypothesis that in HSP90-based therapies simultaneous p53 activation or direct cell cycle inhibition interrupts the deleterious HSF1-HSR axis and improves the efficiency of HSP90 inhibitors. Indeed, we find that the clinically relevant p53 activator Idasanutlin suppresses the HSF1-HSR activity in HSP90 inhibitor-based therapies. This combination synergistically reduces cell viability and accelerates cell death in p53-proficient colorectal cancer (CRC) cells, murine tumor-derived organoids and patient-derived organoids (PDOs). Mechanistically, upon combination therapy human CRC cells strongly upregulate p53-associated pathways, apoptosis, and inflammatory immune pathways. Likewise, in the chemical AOM/DSS CRC model in mice, dual HSF1-HSP90 inhibition strongly represses tumor growth and remodels immune cell composition, yet displays only minor toxicities in mice and normal mucosa-derived organoids. Importantly, inhibition of the cyclin dependent kinases 4 and 6 (CDK4/6) under HSP90 inhibition phenocopies synergistic repression of the HSR in p53-proficient CRC cells. Even more important, in p53-deficient (mutp53-harboring) CRC cells, an HSP90 inhibition in combination with CDK4/6 inhibitors similarly suppresses the HSF1-HSR system and reduces cancer growth. Likewise, p53-mutated PDOs strongly respond to dual HSF1-HSP90 pathway inhibition and thus, providing a strategy to target CRC independent of the p53 status. In sum, activating p53 (in p53-proficient cancer cells) or inhibiting CDK4/6 (independent of the p53 status) provide new options to improve the clinical outcome of HSP90-based therapies and to enhance colorectal cancer therapy.

Regulation of phosphosignaling pathways involved in transcription of cell cycle target genes by TRH receptor activation in GH1 cells

Thyrotropin-releasing hormone (TRH) is known to activate several cellular signaling pathway, but the activation of the TRH receptor (TRH-R) has not been reported to regulate gene transcription. The aim of this study was to identify phosphosignaling pathways and phosphoprotein complexes associated with gene transcription in GH1 pituitary cells treated with TRH or its analog, taltirelin (TAL), using label-free bottom-up mass spectrometry-based proteomics. Our detailed analysis provided insight into the mechanism through which TRH-R activation may regulate the transcription of genes related to the cell cycle and proliferation. It involves control of the signaling pathways for β-catenin/Tcf, Notch/RBPJ, p53/p21/Rbl2/E2F, Myc, and YY1/Rb1/E2F through phosphorylation and dephosphorylation of their key components. In many instances, the phosphorylation patterns of differentially phosphorylated phosphoproteins in TRH- or TAL-treated cells were identical or displayed a similar trend in phosphorylation. However, some phosphoproteins, especially components of the Wnt/β-catenin/Tcf and YY1/Rb1/E2F pathways, exhibited different phosphorylation patterns in TRH- and TAL-treated cells. This supports the notion that TRH and TAL may act, at least in part, as biased agonists. Additionally, the deficiency of β-arrestin2 resulted in a reduced number of alterations in phosphorylation, highlighting the critical role of β-arrestin2 in the signal transduction from TRH-R in the plasma membrane to transcription factors in the nucleus.

DNAJ heat shock protein family member C1 can regulate proliferation and migration in hepatocellular carcinoma

Background

DNAJ heat shock protein family (Hsp40) member C1(DNAJC1) is a member of the DNAJ family. Some members of the DNAJ gene family had oncogenic properties in many cancers. However, the role of DNAJC1 in hepatocellular carcinoma (HCC) was unclear.

Methods

In this study, expression and prognostic value of DNAJC1 in HCC were analyzed by bioinformatics. Quantitative real-time PCR and Western blotting were used to verify DNAJC1 expression in liver cancer cell lines. Furthermore, immunohistochemical (IHC) was used to detect DNAJC1 expression in liver cancer tissues. Subsequently, the effect of DNAJC1 on the proliferation, migration, invasion and apoptosis of HCC cells was detected by knocking down DNAJC1. Finally, gene set enrichment analysis (GSEA) was used to investigate the potential mechanism of DNAJC1 and was verified by Western blotting.

Results

DNAJC1 was highly expressed in HCC and was significantly associated with the prognosis of patients with HCC. Importantly, the proliferation, migration and invasion of Huh7 and MHCC97H cells were inhibited by the knockdown of DNAJC1 and the knockdown of DNAJC1 promoted Huh7 and MHCC97H cell apoptosis. Furthermore, compared to the negative control group, DNAJC1 knockdown in Huh7 and MHCC97H cells promoted the expression of p21, p53, p-p53(Ser20), Bax and E-cadherin proteins, while inhibiting the expression of PARP, MMP9, Vimentin, Snai1, Bcl-2 and N-cadherin proteins.

Conclusions

DNAJC1 had a predictive value for the prognosis of HCC. Knockdown of DNAJC1 may inhibit HCC cell proliferation, migration and invasion and promote the HCC cell apoptosis through p53 and EMT signaling pathways.

Transcriptomic profiles of the ruminal wall in Italian Mediterranean dairy buffaloes fed green forage

BACKGROUND

Green feed diet in ruminants exerts a beneficial effect on rumen metabolism and enhances the content of milk nutraceutical quality. At present, a comprehensive analysis focused on the identification of genes, and therefore, biological processes modulated by the green feed in buffalo rumen has never been reported. We performed RNA-sequencing in the rumen of buffaloes fed a total mixed ration (TMR) + the inclusion of 30% of ryegrass green feed (treated) or TMR (control), and identified differentially expressed genes (DEGs) using EdgeR and NOISeq tools.

RESULTS

We found 155 DEGs using EdgeR (p-values < 0.05) and 61 DEGs using NOISeq (prob ≥0.8), 30 of which are shared. The rt-qPCR validation suggested a higher reliability of EdgeR results as compared with NOISeq data, in our biological context. Gene Ontology analysis of DEGs identified using EdgeR revealed that green feed modulates biological processes relevant for the rumen physiology and, then, health and well-being of buffaloes, such as lipid metabolism, response to the oxidative stress, immune response, and muscle structure and function. Accordingly, we found: (i) up-regulation of HSD17B13, LOC102410803 (or PSAT1) and HYKK, and down-regulation of CDO1, SELENBP1 and PEMT, encoding factors involved in energy, lipid and amino acid metabolism; (ii) enhanced expression of SIM2 and TRIM14, whose products are implicated in the immune response and defense against infections, and reduced expression of LOC112585166 (or SAAL1), ROR2, SMOC2, and S100A11, encoding pro-inflammatory factors; (iii) up-regulation of NUDT18, DNAJA4 and HSF4, whose products counteract stressful conditions, and down-regulation of LOC102396388 (or UGT1A9) and LOC102413340 (or MRP4/ABCC4), encoding detoxifying factors; (iv) increased expression of KCNK10, CACNG4, and ATP2B4, encoding proteins modulating Ca²⁺ homeostasis, and reduced expression of the cytoskeleton-related MYH11 and DES.

CONCLUSION

Although statistically unpowered, this study suggests that green feed modulates the expression of genes involved in biological processes relevant for rumen functionality and physiology, and thus, for welfare and quality production in Italian Mediterranean dairy buffaloes. These findings, that need to be further confirmed through the validation of additional DEGs, allow to speculate a role of green feed in the production of nutraceutical molecules, whose levels might be enhanced also in milk.

Prognostic model and immunotherapy prediction based on molecular chaperone-related lncRNAs in lung adenocarcinoma

Introduction: Molecular chaperones and long non-coding RNAs (lncRNAs) have been confirmed to be closely related to the occurrence and development of tumors, especially lung cancer. Our study aimed to construct a kind of molecular chaperone-related long non-coding RNAs (MCRLncs) marker to accurately predict the prognosis of lung adenocarcinoma (LUAD) patients and find new immunotherapy targets.

Methods: In this study, we acquired molecular chaperone genes from two databases, Genecards and molecular signatures database (MsigDB). And then, we downloaded transcriptome data, clinical data, and mutation information of LUAD patients through the Cancer Genome Atlas (TCGA). MCRLncs were determined by Spearman correlation analysis. We used univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis to construct risk models. Kaplan-meier (KM) analysis was used to understand the difference in survival between high and low-risk groups. Nomogram, calibration curve, concordance index (C-index) curve, and receiver operating characteristic (ROC) curve were used to evaluate the accuracy of the risk model prediction. In addition, we used gene ontology (GO) enrichment analysis and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses to explore the potential biological functions of MCRLncs. Immune microenvironmental landscapes were constructed by using single-sample gene set enrichment analysis (ssGSEA), tumor immune dysfunction and exclusion (TIDE) algorithm, “pRRophetic” R package, and “IMvigor210” dataset. The stem cell index based on mRNAsi expression was used to further evaluate the patient’s prognosis.

Results: Sixteen MCRLncs were identified as independent prognostic indicators in patients with LUAD. Patients in the high-risk group had significantly worse overall survival (OS). ROC curve suggested that the prognostic features of MCRLncs had a good predictive ability for OS. Immune system activation was more pronounced in the high-risk group. Prognostic features of the high-risk group were strongly associated with exclusion and cancer-associated fibroblasts (CAF). According to this prognostic model, a total of 15 potential chemotherapeutic agents were screened for the treatment of LUAD. Immunotherapy analysis showed that the selected chemotherapeutic drugs had potential application value. Stem cell index mRNAsi correlates with prognosis in patients with LUAD.

Conclusion: Our study established a kind of novel MCRLncs marker that can effectively predict OS in LUAD patients and provided a new model for the application of immunotherapy in clinical practice.

Administration of 4‑hexylresorcinol increases p53‑mediated transcriptional activity in oral cancer cells with the p53 mutation

The p53 mutation is inherent in over 50% of human cancers. In head and neck squamous cell carcinoma, the p53 mutation is associated with a poor prognosis. 4-Hexylresorcinol (4HR) is a pharmacologic chaperone. The present study aimed to investigate the effect of 4HR on p53 transcriptional activity in oral carcinoma cells with p53 mutations. To identify conformational changes induced by 4HR administration, peptides including the DNA-binding domain from mutant and wild-type p53 were synthesized, and Fourier transform infrared spectroscopy was performed. To determine the effect of 4HR on p53 mutant carcinoma cells, western blot analysis, p53 transcriptional activity analysis, MTT assay and apoptosis immunocytochemistry were performed. The YD-15 cell line has a mutation in the DNA binding domain of p53 (Glu258Ala). When p53 Ala-258 was coupled by 4HR, the p53 Ala-258 structure lost its original conformation and approached a conformation similar to that of p53 Glu-258. In the cell experiments, 4HR administration to p53 mutant cells increased p53 transcriptional activity and the expression levels of apoptosis-associated proteins such as B-cell lymphoma 2 (BCL2), BCL2-associated X (BAX) and BCL2-associated agonist of cell death (BAD). Accordingly, 4HR administration on YD-15 cells decreased cell viability and increased apoptosis. In conclusion, 4HR is a potential substance for use in the recovery of loss-of-function in mutant p53 as a pharmacologic chaperone.

Inhibition of TP53 Mutant Oral Cancer by Reactivating p53

Background: Mutation of p53 is a frequent event, and mutant p53 exhibits low levels of acetylation and phosphorylation. This study aimed to investigate the effect of the histone deacetylase (HDAC) inhibitor, 4-hexylresorcinol (4HR), on the acetylation and phosphorylation of mutant p53 carcinoma cells and its therapeutic effects in a xenograft model. Methods: To determine the effect of 4HR on the acetylation and phosphorylation of p53, western blot analysis was performed using YD-9 and YD-15 cells. p53 siRNA was used to examine whether 4HR acts in a p53-dependent or independent manner. This was evaluated using a xenograft model. Results: In in vitro experiments when the concentration of 4HR was increased, the expression levels of HDAC4, acetylated p53 (Ac-p53), and phosphorylated p53 (p-p53) increased. Transfection with TP53 siRNA successfully suppressed p53 protein and TP53 mRNA expression. When 4HR was administered to a xenograft model, the tumour expansion rate was suppressed compared with the control, and the mice exhibited a higher survival rate. Conclusions: Our findings reveal that 4HR is a potential agent that restores loss of function in mutant p53 cancer cells via acetylation and phosphorylation of p53 as well as inhibition of HDAC4.