Clinical, prognostic, and therapeutic significance of heat shock protein 27 in bladder cancer

The heat shock protein Hsp27 controls mitochondrial function by modulating ceramide generation

Sphingolipids have key functions in membrane structure and cellular signaling. Ceramide is the central molecule of the sphingolipid metabolism and is generated by ceramide synthases (CerS) in the de novo pathway. Despite their critical function, mechanisms regulating CerS remain largely unknown. Using an unbiased proteomics approach, we find that the small heat shock protein 27 (Hsp27) interacts specifically with CerS1 but not other CerS. Functionally, our data show that Hsp27 acts as an endogenous inhibitor of CerS1. Wild-type Hsp27, but not a mutant deficient in CerS1 binding, inhibits CerS1 activity. Additionally, silencing of Hsp27 enhances CerS1-generated ceramide accumulation in cells. Moreover, phosphorylation of Hsp27 modulates Hsp27-CerS1 interaction and CerS1 activity in acute stress-response conditions. Biologically, we show that Hsp27 knockdown impedes mitochondrial function and induces lethal mitophagy in a CerS1-dependent manner. Overall, we identify an important mode of CerS1 regulation and CerS1-mediated mitophagy through protein-protein interaction with Hsp27.

Untangling the complexity of heat shock protein 27 in cancer and metastasis

Heat shock protein 27 is a type of molecular chaperone whose expression gets up-regulated due to reaction towards different stressful triggers including anticancer treatments. It is known to be a major player of resistance development in cancer cells, whereby cells are sheltered against the therapeutics that normally activate apoptosis. Heat shock protein 27 (HSP27) is one of the highly expressed proteins during various cellular insults and is a strong tumor survival factor. HSP27 influences various cellular pathways associated with cancer cell survival and growth such as apoptosis, autophagy, metastasis, angiogenesis, epithelial to mesenchymal transition, etc. HSP27 is molecular machinery which prevents the clumping of numerous substrates or client proteins which get mutated in cancer. It has been reported in several studies that targeting HSP27 is difficult because of its dynamic structure and absence of an ATP-binding site. Here, in this review, we have summarized different modulators of HSP27 and their mechanism of action as well. Effect of deregulated HSP27 in various cancer models, limitations of targeting HSP27, resistance against the conventional drugs generated due to the overexpression of HSP27, and measures to counteract this effect have also been discussed here in detail.

Evaluation of the Small Heat Shock Protein Family Members HSPB2 and HSPB3 in Bladder Cancer Prognosis and Progression

Bladder cancer (BlCa) represents the sixth most commonly diagnosed type of male malignancy. Due to the clinical heterogeneity of BlCa, novel markers would optimize treatment efficacy and improve prognosis. The small heat shock proteins (sHSP) family is one of the major groups of molecular chaperones responsible for the maintenance of proteome functionality and stability. However, the role of sHSPs in BlCa remains largely unknown. The present study aimed to examine the association between HSPB2 and HSPB3 expression and BlCa progression in patients, and to investigate their role in BlCa cells. For this purpose, a series of experiments including reverse transcription-quantitative PCR, Western blotting, MTT assay and flow cytometry were performed. Initial analyses revealed increased vs. human transitional carcinoma cells, expression levels of the HSPB2 and HSPB3 genes and proteins in high grade BlCa cell lines. Therefore, we then evaluated the clinical significance of the HSPB2 and HSPB3 genes expression levels in bladder tumor samples and matched adjusted normal bladder specimens. Total RNA from 100 bladder tumor samples and 49 paired non-cancerous bladder specimens were isolated, and an accurate SYBR-Green based real-time quantitative polymerase chain reaction (qPCR) protocol was developed to quantify HSPB2 and HSPB3 mRNA levels in the two cohorts of specimens. A significant downregulation of the HSPB2 and HSPB3 genes expression was observed in bladder tumors as compared to matched normal urothelium; yet, increased HSPB2 and HSPB3 levels were noted in muscle-invasive (T2-T4) vs. superficial tumors (TaT1), as well as in high-grade vs. low-grade tumors. Survival analyses highlighted the significantly higher risk for post-treatment disease relapse in TaT1 patients poorly expressing HSPB2 and HSPB3 genes; this effect tended to be inverted in advanced disease stages (muscle-invasive tumors) indicating the biphasic impact of HSPB2, HSPB3 genes in BlCa progression. The pro-survival role of HSPB2 and HSPB3 in advanced tumor cells was also evident by our finding that HSPB2, HSPB3 genes expression silencing in high grade BlCa cells enhanced doxorubicin toxicity. These findings indicate that the HSPB2, HSPB3 chaperone genes have a likely pro-survival role in advanced BlCa; thus, they can be targeted as novel molecular markers to optimize treatment efficacy in BlCa and to limit unnecessary interventions.

Multi-platform-based characterization of ferroptosis in human colorectal cancer

Ferroptosis is a type of programmed cell death potentially playing an important role in colorectal cancer (CRC) development. However, comprehensive investigations toward ferroptosis in human CRC are lacking. Here, we performed multiple investigations on cancer and para-cancer tissues. We demonstrated that the changes of structural variation and chromatin accessibility in CRC were more associated with the altered mRNA expression of ferroptosis-related genes (FRGs), and the expression of CDKN2A, GPX4, ALOXE3, and LINC00336 was related to the overall survival rates. Subsequently, we revealed that CYBB and YAP1 were potentially the hub genes, and that HSF1 and STAT2 were potentially FRGs’ upstream transcription factors. Finally, we depicted the crosstalk between ferroptosis and necrosis, autophagy, and apoptosis. Based on multi-dimensional analyses, we characterized ferroptosis, probable core genes, and the upstream regulators in human CRC. The findings here may improve our understanding of ferroptosis in CRC and provide new opportunities for clinical diagnosis and treatment.

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Characterize ferroptosis in CRC from DNA, RNA, and protein to epigenetic modification

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The potentially functional or hub genes in ferroptosis at multiple molecular levels

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Putative ferroptosis regulators (transcription factors) in human CRC cells

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The genes that probably link ferroptosis to necrosis, autophagy, and apoptosis

SUMOylation of HSP27 regulates PKM2 to promote esophageal squamous cell carcinoma progression

A previous proteomic screening of differentially expressed biomarkers between Kazakh patients with esophageal squamous cell carcinoma (ESCC) and normal adjacent tissues demonstrated that heat shock protein 27 (HSP27) and pyruvate kinase isoenzyme M2 (PKM2) were both highly expressed in ESCC samples compared with normal controls. However, the regulatory association between HSP27 and PKM2 in ESCC remains elusive. In the present study, immunohistochemistry and immunoblotting were adopted to examine the expression of HSP27, PKM2 and other relevant biomarkers involved in epithelial‑to‑mesenchymal transition in clinical tissue samples. The interactions between proteins were detected by co‑immunoprecipitation (Co‑IP) assay and further confirmed by immunofluorescence assay. The growth and motility of ESCC cells were examined by MTT, Transwell and wound healing assays. Overexpression of HSP27 was found to be significantly associated with T‑cell classification, lymph node metastasis and poor prognosis in ESCC. In addition, HSP27 expression was significantly correlated with PKM2 expression in ESCC specimens. Functionally, knockdown of HSP27 inhibited the growth and motility of ESCC cells. Moreover, HSP27 was found to directly interact with small ubiquitin‑related modified protein 2/3 (SUMO2/3) in ESCC cell lines, as evidenced by Co‑IP and laser confocal imaging. In addition, downregulation of HSP27 was shown to decrease PKM2 and E‑cadherin expression. Knockdown of SUMO2/3 was observed to reduce the expression of HSP27, PKM2 and EMT‑related biomarkers. The results of the present study indicated that the SUMOylation of HSP27 enhances the proliferation, invasion and migration of ESCC cells via PKM2.

HMGN5 promotes IL-6-induced epithelial-mesenchymal transition of bladder cancer by interacting with Hsp27

Bladder cancer (BC) is one of the most common cancers worldwide, with a high rate of recurrence and poor outcomes. High-mobility group nucleosome-binding domain 5 (HMGN5) is overexpressed in many cancers and could cause carcinogenesis in BC. By protein-protein-interaction (PPI) analysis, we found that heat shock protein 27 (Hsp27), also a crucial functional factor in BC carcinogenesis, is significantly related to HMGN5. Hsp27 is required for IL-6-mediated EMT via STAT3/Twist signaling in prostate cancer. Here, we hypothesize that HMGN5 may interact with Hsp27 to affect IL-6-induced EMT and invasion in BC via STAT3 signaling. In the present study, we found that HMGN5 and Hsp27 are highly expressed in BC tissues and positively correlated with each other. HMGN5 interacts with Hsp27 in vitro, to modulate the cell invasion and EMT in BC. Moreover, HMGN5 could modulate IL-6-Hsp27-induced EMT and invasion in BC cells by regulating STAT3 phosphorylation and STAT3 targeting of the Twist promoter. HMGN5 interacts with Hsp27 to promote tumor growth in a human BC xenograft model in nude mice. In summary, HMGN5 interacts with Hsp27 to promote IL-6-induced EMT, therefore promoting invasion in BC and contributing to the progression of BC.

Increased Expression of DNAJC12 is Associated with Aggressive Phenotype of Gastric Cancer

BACKGROUND

Identification of gastric cancer-related molecules is necessary to elucidate the pathological mechanisms of this heterogeneous disease. The purpose of this study was to identify novel genes associated with aggressive phenotypes of gastric cancer.

METHODS

Global expression profiling was conducted using tissues from four patients with metastatic gastric cancer to identify genes overexpressed in gastric cancer. Fifteen gastric cell lines and 262 pairs of surgically resected gastric tissues were subjected to mRNA expression analysis. The contribution of the candidate gene on gastric cancer cell proliferation, invasion, adhesion, and migration were evaluated using small interfering RNA.

RESULTS

DnaJ heat shock protein family (Hsp40) member C12 (DNAJC12) was identified as a candidate gene by transcriptome analysis. In clinical samples, DNAJC12 mRNA levels were higher in gastric cancer tissues compared with normal adjacent tissues. Patients with high DNAJC12 expression showed significantly shorter overall survival in our cohort and in the extra-validation cohort analyzed by a published microarray dataset. High DNAJC12 expression in gastric cancer tissues was significantly associated with lymphatic involvement, infiltrative growth type, lymph node metastasis, and advanced stage and was identified as an independent prognostic factor for overall survival in multivariable analysis. Increased expression of DNAJC12 was found in 12 of 14 examined gastric cancer cell lines. Knockdown of DNAJC12 expression significantly decreased the proliferation and invasion abilities of gastric cancer cells.

CONCLUSIONS

Our findings support DNAJC12 as a candidate gene associated with aggressive phenotypes of gastric cancer.

Anticancer Effects of Green Tea and the Underlying Molecular Mechanisms in Bladder Cancer

Green tea and green tea polyphenols (GTPs) are reported to inhibit carcinogenesis and malignant behavior in several diseases. Various in vivo and in vitro studies have shown that GTPs suppress the incidence and development of bladder cancer. However, at present, opinions concerning the anticancer effects and preventive role of green tea are conflicting. In addition, the detailed molecular mechanisms underlying the anticancer effects of green tea in bladder cancer remain unclear, as these effects are regulated by several cancer-related factors. A detailed understanding of the pathological roles and regulatory mechanisms at the molecular level is necessary for advancing treatment strategies based on green tea consumption for patients with bladder cancer. In this review, we discuss the anticancer effects of GTPs on the basis of data presented in in vitro studies in bladder cancer cell lines and in vivo studies using animal models, as well as new treatment strategies for patients with bladder cancer, based on green tea consumption. Finally, on the basis of the accumulated data and the main findings, we discuss the potential usefulness of green tea as an antibladder cancer agent and the future direction of green tea-based treatment strategies for these patients.