Kindlin-2 regulates colonic cancer stem-like cells survival and self-renewal via Wnt/β-catenin mediated pathway

BACKGROUND

Cancer Stem Cells (CSCs) have emerged as a critical mediator in recurrence and resistance in cancers. Kindlin-isoform (1 and 2) binds with cytoplasmic β-tail of integrin and are essential co-activators of integrin function. Given their important function in regulating cancer hallmarks such as cell proliferation, invasion, migration, and metastasis, we hypothesize that it might play a critical role in CSC growth, survival, and self-renewal of colon cancer.

MATERIALS AND METHODS

Using knockdown approaches, we inhibited Kindlin-2 expression in HCT116 and HT29 colon cancer cells. Extreme limiting dilution and self-renewal assay were performed to measure the role of Kindlin in colonic CSC. Standard methods such as qRT-PCR and western blotting were carried out to understand the signaling cascade by which Kindlin regulates CSC marker expression and downstream targets.

RESULTS

Our data show isoform-specific upregulation of Kindlin-2 in colonic CSCs. The silencing of Kindlin-2 reduces colonosphere formation, decreases CSC size, and self-renewal marker genes such as CD-133, CXCR-4, LGR-5, and C-MYC. Kindlin-2 silencing reduces colonosphere proliferation, invasion, and migration of colonic CSCs. Mechanistically, Kindlin-2 silencing reduces the expression, and nuclear localization of β-catenin, and decreases β-catenin target genes such as C-MYC, cyclin D1, DKK-1, and Snail-1.

CONCLUSION

Our study delineates the isoform-specific activity of Kindlin-2 in regulating Colonic CSC. Isoform-specific targeting of Kindlin-2 may be a novel strategy to tackle this devastating disease.

Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties

Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.

Cancer as a biophysical disease: Targeting the mechanical-adaptability program

With the number of cancer cases projected to significantly increase over time, researchers are currently exploring "nontraditional" research fields in the pursuit of novel therapeutics. One emerging area that is steadily gathering interest revolves around cellular mechanical machinery. When looking broadly at the physical properties of cancer, it has been debated whether a cancer could be defined as either stiffer or softer across cancer types. With numerous articles supporting both sides, the evidence instead suggests that cancer is not particularly regimented. Instead, cancer is highly adaptable, allowing it to endure the constantly changing microenvironments cancer cells encounter, such as tumor compression and the shear forces in the vascular system and body. What allows cancer cells to achieve this adaptability are the particular proteins that make up the mechanical network, leading to a particular mechanical program of the cancer cell. Coincidentally, some of these proteins, such as myosin II, α-actinins, filamins, and actin, have either altered expression in cancer and/or some type of direct involvement in cancer progression. For this reason, targeting the mechanical system as a therapeutic strategy may lead to more efficacious treatments in the future. However, targeting the mechanical program is far from trivial. As involved as the mechanical program is in cancer development and metastasis, it also helps drive many other key cellular processes, such as cell division, cell adhesion, metabolism, and motility. Therefore, anti-cancer treatments targeting the mechanical program must take great care to avoid potential side effects. Here, we introduce the potential of targeting the mechanical program while also providing its challenges and shortcomings as a strategy for cancer treatment.

LncRNA TP73-AS1 Exacerbates the Non-Small-Cell Lung Cancer (NSCLC) Process via Regulating miR-125a-3p-Mediated ACTN4

Background

LncRNA TP73-AS1 has been revealed to exert a noteworthy impact on the occurrence and advancement of different cancers. In this study, we explored the function of TP73-AS1 in tumor growth, cell progression as well as the relevant molecular mechanism in non-small-cell lung cancer (NSCLC).

Methods

QRT-PCR was employed to assess the expression of TP73-AS1, miR‐125a-3p, and actinin alpha 4 (ACTN4) in NSCLC cells. The biological effect of TP73-AS1 on NSCLC cells was assessed by cell transfection, CCK8, and transwell experiments. We further predicted the interaction among RNAs (TP73-AS1, miR-125a-3p, and ACTN4) through bioinformatics online tools and verified via luciferase reporter, RNA immunoprecipitation, and qRT-PCR assays. Xenograft models of SPC-A1 cells were conducted to test how TP73-AS1 regulates tumorigenesis. Western blot, as well as the immunohistochemistry (IHC) assays, was utilized to measure the expression levels. Functions of TP73-AS1 in NSCLC progression through the miR-125a-3p/ACTN4 axis were investigated by rescue experiments.

Results

Knockdown of TP73-AS1 suppressed the growth and simultaneously attenuated the migration and invasion ability of NSCLC SPC-A1 and A549 cells. Bioinformatics and molecular mechanism assays demonstrated that TP73-AS1 could bind to miR-125a-3p/ACTN4 and regulate their expression. Moreover, the rescued‐function experiment demonstrated that suppressing miR-125a-3p or elevating ACTN4 turned around the suppression effect of sh-TP73-AS1 on NSCLC progression. TP73-AS1 inhibition could also inhibit the NSCLC tumor growth and correspondingly regulated the expression of miR-125a-3p and ACTN4 in the tumor xenograft model.

Conclusion

The present study indicated that TP73-AS1 affects NSCLC progression through a new competitive RNA (ceRNA) regulatory network of miR-125a-3p/ACTN4, providing an underlying target for NSCLC treatment in the future.

Biomechanics of cancer stem cells

Cancer stem cells (CSCs) have been believed to be one driving force for tumor progression and drug resistance. Despite the significance of biochemical signaling in malignancy, highly malignant tumor cells or CSCs exhibit lower cellular stiffness than weakly malignant cells or non-CSCs, which are softer than their healthy counterparts, suggesting the inverse correlation between cell stiffness and malignancy. Recent years have witnessed the rapid accumulation of evidence illustrating the reciprocity between cell cytoskeleton/mechanics and CSC functions and the potential of cellular stiffness for specific targeting of CSCs. However, a systematic understanding of tumor cell mechanics and their role in CSCs and tumor progression is still lacking. The present review summarizes the recent progress in the alterations of tumor cell cytoskeleton and stiffness at different stages of tumor progression and recapitulates the relationship between cellular stiffness and CSC functions. The altered cell mechanics may mediate the mechanoadaptive responses that possibly empower CSCs to survive and thrive during metastasis. Furthermore, we highlight the possible impact of tumor cell mechanics on CSC malignancy, which may potentiate low cell stiffness as a mechanical marker for CSC targeting.

RNF38 suppress growth and metastasis via ubiquitination of ACTN4 in nasopharyngeal carcinoma

Background

Accumulated evidence suggests that RING finger proteins (RNFs) are involved in the carcinogenesis of cancers. However, RNF38, a member of the RNF protein family, has not been studied in nasopharyngeal carcinoma (NPC).

Methods

RNF38 expression was analyzed by RT-PCR, Western blotting and Immunohistochemistry. Biological functions of RNF38 were evaluated by cell growth, colony formation, apoptosis, migration and invasion assays in vitro. Xenograft growth and lung metastasis models were conducted to investigate the effect of RNF38 in vivo. Liquid chromatography coupled with tandem mass spectrometry, co-immunoprecipitation, and CHX assay were implemented to detect the interaction among RNF38 and ACTN4.

Results

RNF38 was significantly downregulated in NPC cells and tissues. Immunohistochemistry implied that loss of RNF38 was an independent prognostic factor for poor outcomes of NPC patients. Gain- and loss-of-function experiments showed that RNF38 inhibited proliferation and metastasis in NPC in vitro and in vivo. Upregulation of RNF38 promoted apoptosis of NPC cells to etoposide but not cisplatin. ACTN4 was upregulated in NPC and negatively correlated with RNF38. Mechanistic investigations suggested that RNF38 inactivates the NF-𝛋B and ERK1/2 signaling pathways by inducing ubiquitination and degradation of ACTN4. RNF38 suppress the development of NPC by interacting with ACTN4.

Conclusions

RNF38 plays a potential cancer suppressor gene role in NPC tumorigenesis and is a prognostic biomarker in NPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09641-x.

The long and short non-coding RNAs modulating EZH2 signaling in cancer

Non-coding RNAs (ncRNAs) are a large family of RNA molecules with no capability in encoding proteins. However, they participate in developmental and biological processes and their abnormal expression affects cancer progression. These RNA molecules can function as upstream mediators of different signaling pathways and enhancer of zeste homolog 2 (EZH2) is among them. Briefly, EZH2 belongs to PRCs family and can exert functional roles in cells due to its methyltransferase activity. EZH2 affects gene expression via inducing H3K27me3. In the present review, our aim is to provide a mechanistic discussion of ncRNAs role in regulating EZH2 expression in different cancers. MiRNAs can dually induce/inhibit EZH2 in cancer cells to affect downstream targets such as Wnt, STAT3 and EMT. Furthermore, miRNAs can regulate therapy response of cancer cells via affecting EZH2 signaling. It is noteworthy that EZH2 can reduce miRNA expression by binding to promoter and exerting its methyltransferase activity. Small-interfering RNA (siRNA) and short-hairpin RNA (shRNA) are synthetic, short ncRNAs capable of reducing EZH2 expression and suppressing cancer progression. LncRNAs mainly regulate EZH2 expression via targeting miRNAs. Furthermore, lncRNAs induce EZH2 by modulating miRNA expression. Circular RNAs (CircRNAs), like lncRNAs, affect EZH2 expression via targeting miRNAs. These areas are discussed in the present review with a focus on molecular pathways leading to clinical translation.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

The role of polyphenols in overcoming cancer drug resistance: a comprehensive review

Chemotherapeutic drugs are used to treat advanced stages of cancer or following surgery. However, cancers often develop resistance against drugs, leading to failure of treatment and recurrence of the disease. Polyphenols are a family of organic compounds with more than 10,000 members which have a three-membered flavan ring system in common. These natural compounds are known for their beneficial properties, such as free radical scavenging, decreasing oxidative stress, and modulating inflammation. Herein, we discuss the role of polyphenols (mainly curcumin, resveratrol, and epigallocatechin gallate [EGCG]) in different aspects of cancer drug resistance. Increasing drug uptake by tumor cells, decreasing drug metabolism by enzymes (e.g. cytochromes and glutathione-S-transferases), and reducing drug efflux are some of the mechanisms by which polyphenols increase the sensitivity of cancer cells to chemotherapeutic agents. Polyphenols also affect other targets for overcoming chemoresistance in cancer cells, including cell death (i.e. autophagy and apoptosis), EMT, ROS, DNA repair processes, cancer stem cells, and epigenetics (e.g. miRNAs).

α-actinin-4 drives invasiveness by regulating myosin IIB expression and myosin IIA localization

The mechanisms by which the mechanoresponsive actin crosslinking protein α-actinin-4 (ACTN4) regulates cell motility and invasiveness remains incompletely understood. Here we show that in addition to regulating protrusion dynamics and focal adhesion formation, ACTN4 transcriptionally regulates expression of non-muscle myosin IIB (NMM IIB), which is essential for mediating nuclear translocation during 3D invasion. We further show that an indirect association between ACTN4 and NMM IIA mediated by a functional F-actin cytoskeleton is essential for retention of NMM IIA at the cell periphery and modulation of focal adhesion dynamics. A protrusion-dependent model of confined migration recapitulating experimental observations predicts a dependence of protrusion forces on the degree of confinement and on the ratio of nucleus to matrix stiffness. Together, our results suggest that ACTN4 is a master regulator of cancer invasion that regulates invasiveness by controlling NMM IIB expression and NMM IIA localization.

Development of biomarkers for predicting recurrence by determining the metastatic ability of cancer cells

Adjuvant chemotherapy has been carried out for patients with cancer who underwent curative resection, but it is basically not needed for patients without micro-metastatic lesions who undergo a perfectly curative surgical operation. The patients who need adjuvant chemotherapy are defined as those whose micro-metastases cannot be detected by imaging modalities in the other sites of the resective areas, despite curative resection for the primary sites. If biomarkers to efficiently evaluate the metastatic potential of each patient could be developed, we may be able to provide personalized adjuvant chemotherapy in the clinical setting. Actinin-4 (ACTN4, gene name ACTN4) is an actin-bundling protein that we identified in 1998 as a novel molecule involved in cancer invasion and metastasis. Protein overexpression of actinin-4 in cancer cells leads to the invasive phenotype, and patients with gene amplification of ACTN4 have a worse prognosis than patients with a normal copy number in some cancers, including pancreas, lung, and salivary gland cancers. In this review, the biological roles of actinin-4 for cancer invasion and metastasis are summarized, and the potential usefulness of actinin-4 as a biomarker for evaluation of metastatic ability is examined.

ACTN1 supports tumor growth by inhibiting Hippo signaling in hepatocellular carcinoma

Background

Alpha actinins (ACTNs) are major cytoskeletal proteins and exhibit many non-muscle functions. Emerging evidence have uncovered the regulatory role of ACTNs in tumorigenesis, however, the expression pattern, biological functions, and underlying mechanism of ACTN1 in hepatocellular carcinoma (HCC) remain largely unexplored.

Methods

Immunohistochemical analysis of a HCC tissue microarray (n = 157) was performed to determine the expression pattern and prognostic value of ACTN1 in HCC. In vitro loss-of-function study in HCC cells were carried out to investigate ACTN1 knockdown on cell proliferation. In vivo subcutaneous xenograft model and intrahepatic transplantation model were generated to decipher the contribution of ACTN1 in the tumor growth of HCC. Gene set enrichment analysis, quantitative real-time PCR, Co-immunoprecipitation, immunofluorescence and western blotting were performed to identify the underlying molecular mechanism.

Results

It was found that ACTN1 was significantly upregulated in HCC tissues and closely related to llpha-fetoprotein level, tumor thrombus, tumor size, TNM stage and patient prognoses. Knockdown of ACTN1 suppressed in vitro cell proliferation and in vivo tumor growth of HCC cells. Mechanistically, knockdown of ACTN1 increased Hippo signaling pathway activity and decreased Rho GTPases activities. Mechanistically, ACTN1 could competitively interact with MOB1 and decrease the phosphorylation of LATS1 and YAP. The growth-promoting effect induced by ACTN1 was significantly abrogated by pharmacological inhibition of YAP with verteporfin or super-TDU.

Conclusions

ACTN1 is highly expressed in HCC tissues and acts as a tumor promoter by suppressing Hippo signaling via physical interaction with MOB1. ACTN1 may serve as a potential prognostic marker and therapeutic target for HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-020-01821-6.

Dual relationship between long non-coding RNAs and STAT3 signaling in different cancers: New insight to proliferation and metastasis

Uncontrolled growth and metastasis of cancer cells is an increasing challenge for overcoming cancer, and improving survival of patients. Complicated signaling networks account for proliferation and invasion of cancer cells that need to be elucidated for providing effective cancer therapy, and minimizing their malignancy. Long non-coding RNAs (lncRNAs) are RNA molecules with a length of more than 200 nucleotides. They participate in cellular events, and their dysregulation in a common phenomenon in different cancers. Noteworthy, lncRNAs can regulate different molecular pathways, and signal transducer and activator of transcription 3 (STAT3) is one of them. STAT3 is a tumor-promoting factors in cancers due to its role in cancer proliferation (cell cycle progression and apoptosis inhibition) and metastasis (EMT induction). LncRNAs can function as upstream mediators of STAT3 pathway, reducing/enhancing its expression. This dual relationship is of importance in affecting proliferation and metastasis of cancer cells. The response of cancer cells to therapy such as chemotherapy and radiotherapy is regulated by lncRNA/STAT3 axis. Tumor-promoting lncRNAs including NEAT1, SNHG3 and H19 induces STAT3 expression, while tumor-suppressing lncRNAs such as MEG3, PTCSC3 and NKILA down-regulate STAT3 expression. Noteworthy, upstream mediators of STAT3 such as microRNAs can be regulated by lncRNAs. These complicated signaling networks are mechanistically described in the current review.

Combined Detection of ACTN4 and SCC-Ag is a Promising Serological Biomarker for Cervical Intraepithelial Neoplasia 3 or Worse: A Case-Control Study

Purpose

Cervical cancer (CC) is a common malignancy in women. Squamous cell carcinoma antigen (SCC-Ag) and cancer antigen (CA)-125 are widely used to help diagnose CC, but novel tumour markers with superior sensitivity and specificity are needed. α-Actinin 4(ACTN4) is overexpressed in CC, though its diagnostic value for CC is unclear. This study examined the diagnostic value of ACTN4 and SCC-Ag as biomarkers for cervical intraepithelial neoplasia (CIN) 3 or worse.

Methods

Women screened for CC at Fujian Medical University Union Hospital were recruited from 2017.1 to 2018.5. Cervical tissues and blood were collected at the same time. Patients pathologically diagnosed as CIN3+ or NILM/CIN1/CIN2 were classified into the case and control groups, respectively. ACTN4 mRNA and protein levels were detected through quantitative PCR and immunohistochemistry, respectively, and ACTN4 and SCC-Ag concentrations were analysed by ELISA. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood rate (PLR), negative likelihood rate (NLR), and Youden index (YI) of ACTN4 and SCC-Ag were evaluated. The optimum cut-off points for ACTN4 and SCC-Ag were determined by receiver operating characteristic (ROC) curve analysis, and accuracy was evaluated by the area under the ROC curve.

Results

In total, 105 patients were classified as CIN3+ cases and 106 as controls. The median ACTN4 levels in case and control tissues were 10.6 and 4.15, respectively. The ACTN4 and SCC-Ag concentrations were significantly higher in cases than controls (P_ACTN4=0.0007; P_SCC-Ag=0.0067). The sensitivity, specificity, PPV, NPV, PLR, NLR and YI of ACTN4 were 68.6%, 76.3%, 76.3%, 72.5%, 2.89, 0.41 and 44.9, respectively; SCC-Ag had a similar diagnostic value (P>0.05), and ACTN4 combined with SCC-Ag had a superior diagnostic value (75.6%, 87.5%, 88.6%, 73.7%, 6.05, 0.28, and 63.1, respectively).

Conclusion

Combined ACTN4 and SCC-Ag detection is a promising serological biomarker for patients with CIN3 or worse.

Study on the regulatory mechanism and experimental verification of icariin for the treatment of ovarian cancer based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Herba Epimedii (Berberidaceae) has the advantages of "nourishing the kidney and reinforcing the Yang". Many species in this genus have long been used in traditional Chinese medicine (TCM) and have been used as anticancer drugs in traditional Chinese herbal medicine formulations. Icariin, a major flavonoid glycoside extracted from Epimedium brevicornum Maxim, has been widely proven to exert an inhibitory effect on ovarian cancer (OC), and icariin can induce apoptosis and inhibit invasion and migration. However, the underlying mechanism remains unclear, so further research is necessary to verify its traditional use.

AIM OF THE STUDY

This study aimed to explore the regulatory mechanism of icariin in the biological network and signalling pathway of OC through network pharmacology and cytological experiments.

METHODS

Public databases and R × 3.6.2 software were adopted to predict the potential targets, construct the protein-protein interaction (PPI) network, and perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. After the network pharmacological analysis, cytological experiments, real-time quantitative PCR (qPCR) and Western blot (WB) analyses were used to verify the key signalling pathway.

RESULTS

The targets related to treatment were TNF, MMP9, STAT3, PIK3CA, ERBB2, MTOR, IL2, PTGS2, KDR, and F2. GO and KEGG enrichment analyses indicated that various kinases and the PI3K/AKT signalling pathway were the most enriched molecules and pathways. Icariin inhibited OC SKOV3 cell proliferation, migration and invasion in vitro and promoted apoptosis by inhibiting the PI3K/AKT signalling pathway.

CONCLUSION

Icariin promotes apoptosis and suppresses SKOV3 cell activities through the PI3K-Akt signalling pathway. This research not only provides a theoretical and experimental basis for more in-depth studies but also offers an efficient method for the rational utilization of a series of icariin flavonoids as anti-tumour drugs.

Involvement of Actin and Actin-Binding Proteins in Carcinogenesis

The actin cytoskeleton plays a crucial role in many cellular processes while its reorganization is important in maintaining cell homeostasis. However, in the case of cancer cells, actin and ABPs (actin-binding proteins) are involved in all stages of carcinogenesis. Literature has reported that ABPs such as SATB1 (special AT-rich binding protein 1), WASP (Wiskott-Aldrich syndrome protein), nesprin, and villin take part in the initial step of carcinogenesis by regulating oncogene expression. Additionally, changes in actin localization promote cell proliferation by inhibiting apoptosis (SATB1). In turn, migration and invasion of cancer cells are based on the formation of actin-rich protrusions (Arp2/3 complex, filamin A, fascin, α-actinin, and cofilin). Importantly, more and more scientists suggest that microfilaments together with the associated proteins mediate tumor vascularization. Hence, the presented article aims to summarize literature reports in the context of the potential role of actin and ABPs in all steps of carcinogenesis.

The Expressions and Mechanisms of Sarcomeric Proteins in Cancers

The sarcomeric proteins control the movement of cells in diverse species, whereas the deregulation can induce tumours in model organisms and occurs in human carcinomas. Sarcomeric proteins are recognized as oncogene and related to tumor cell metastasis. Recent insights into their expressions and functions have led to new cancer therapeutic opportunities. In this review, we appraise the evidence for the sarcomeric proteins as cancer genes and discuss cancer-relevant biological functions, potential mechanisms by which sarcomeric proteins activity is altered in cancer.