Phospholipase D1 Inhibition Linked to Upregulation of ICAT Blocks Colorectal Cancer Growth Hyperactivated by Wnt/β-Catenin and PI3K/Akt Signaling

PLD1 is a key player in cancer stemness and chemoresistance: Therapeutic targeting of cross-talk between the PI3K/Akt and Wnt/β-catenin pathways

The development of chemoresistance is a major challenge in the treatment of several types of cancers in clinical settings. Stemness and chemoresistance are the chief causes of poor clinical outcomes. In this context, we hypothesized that understanding the signaling pathways responsible for chemoresistance in cancers is crucial for the development of novel targeted therapies to overcome drug resistance. Among the aberrantly activated pathways, the PI3K-Akt/Wnt/β-catenin signaling pathway is clinically implicated in malignancies such as colorectal cancer (CRC) and glioblastoma multiforme (GBM). Aberrant dysregulation of phospholipase D (PLD) has been implicated in several malignancies, and oncogenic activation of this pathway facilitates tumor proliferation, stemness, and chemoresistance. Crosstalk involving the PLD and Wnt/β-catenin pathways promotes the progression of CRC and GBM and reduces the sensitivity of cancer cells to standard therapies. Notably, both pathways are tightly regulated and connected at multiple levels by upstream and downstream effectors. Thus, gaining deeper insights into the interactions between these pathways would help researchers discover unique therapeutic targets for the management of drug-resistant cancers. Here, we review the molecular mechanisms by which PLD signaling stimulates stemness and chemoresistance in CRC and GBM. Thus, the current review aims to address the importance of PLD as a central player coordinating cross-talk between the PI3K/Akt and Wnt/β-catenin pathways and proposes the possibility of targeting these pathways to improve cancer therapy and overcome drug resistance.

A positive feedback loop between PLD1 and NF-κB signaling promotes tumorigenesis of nasopharyngeal carcinoma

Phospholipase D (PLD) lipid-signaling enzyme superfamily has been widely implicated in various human malignancies, but its role and underlying mechanism remain unclear in nasopharyngeal carcinoma (NPC). Here, we analyze the expressions of 6 PLD family members between 87 NPC and 10 control samples through transcriptome analysis. Our findings reveal a notable upregulation of PLD1 in both NPC tumors and cell lines, correlating with worse disease-free and overall survival in NPC patients. Functional assays further elucidate PLD1's oncogenic role, demonstrating its pivotal promotion of critical tumorigenic processes such as cell proliferation and migration in vitro, as well as tumor growth in vivo. Notably, our study uncovers a positive feedback loop between PLD1 and the NF-κB signaling pathway to render NPC progression. Specifically, PLD1 enhances NF-κB activity by facilitating the phosphorylation and nuclear translocation of RELA (p65), which in turn binds to the promoter of PLD1, augmenting its expression. Moreover, RELA overexpression significantly rescues the inhibitory effects in PLD1-depleted NPC cells. Importantly, the application of the PLD1 inhibitor, VU0155069, significantly inhibits NPC tumorigenesis in a patient-derived xenograft model. Together, our findings identify PLD1/NF-κB signaling as a positive feedback loop with promising therapeutic and prognostic potential in NPC.

Paeoniflorin inhibits colorectal cancer cell stemness through the miR-3194-5p/catenin beta-interacting protein 1 axis

Paeoniflorin (PF) is a natural plant ingredient with remarkable antitumor effects. Herein, we investigated the biological effects and mechanism of PF in colorectal cancer (CRC) cell stemness. The messenger RNA (mRNA) and protein expressions were assessed using quantitative real-time polymerase chain reaction and western blot. The viability, proliferation, and migration and invasion of CRC cells were evaluated using cell counting kit-8, clone-formation, and transwell migration and invasion assays, respectively. The sphere-formation capacity was determined using the sphere-formation assay. A dual-luciferase reporter gene assay was employed to analyze the interaction between miR-3194-5p and catenin beta-interacting protein 1 (CTNNBIP1). The viability, migration, invasion, epithelial-mesenchymal transition, and stemness of CRC cells were repressed by PF. MiR-3194-5p was upregulated in CRC tissues and cells. MiR-3194-5p knockdown suppressed CRC cell stemness, while miR-3194-5p overexpression had the opposite effect. In addition, the inhibition of CRC cell stemness caused by PF was eliminated by miR-3194-5p overexpression. CTNNBIP1 functioned as the target of miR-3194-5p, whose knockdown abrogated the repression of CRC cell stemness and Wnt/β-catenin signaling activation by PF.PF regulated the miR-3194-5p/CTNNBIP1/Wnt/β-catenin axis to repress CRC cell stemness.

CCN3/NOV Regulates Proliferation and Neuronal Differentiation in Mouse Hippocampal Neural Stem Cells via the Activation of the Notch/PTEN/AKT Pathway

Neural stem cells (NSCs) persist in the subgranular zone (SGZ) throughout the lifespan and hold immense potential for the repair and regeneration of the central nervous system, including hippocampal-related diseases. Several studies have demonstrated that cellular communication network protein 3 (CCN3) regulates multiple types of stem cells. However, the role of CCN3 in NSCs remains unknown. In this study, we identified CCN3 expression in mouse hippocampal NSCs and observed that supplementing CCN3 improved cell viability in a concentration-dependent manner. Additionally, in vivo results showed that the injection of CCN3 in the dentate gyrus (DG) increased Ki-67- and SOX2-positive cells while decreasing neuron-specific class III beta-tubulin (Tuj1) and doublecortin (DCX)-positive cells. Consistently with the in vivo results, supplementing CCN3 in the medium increased the number of BrdU and Ki-67 cells and the proliferation index but decreased the number of Tuj1 and DCX cells. Conversely, both the in vivo and in vitro knockdown of the Ccn3 gene in NSCs had opposite effects. Further investigations revealed that CCN3 promoted cleaved Notch1 (NICD) expression, leading to the suppression of PTEN expression and eventual promotion of AKT activation. In contrast, Ccn3 knockdown inhibited the activation of the Notch/PTEN/AKT pathway. Finally, the effects of changes in CCN3 protein expression on NSC proliferation and differentiation were eliminated by FLI-06 (a Notch inhibitor) and VO-OH (a PTEN inhibitor). Our findings imply that while promoting proliferation, CCN3 inhibits the neuronal differentiation of mouse hippocampal NSCs and that the Notch/PTEN/AKT pathway may be a potential intracellular target of CCN3. Our findings may help develop strategies to enhance the intrinsic potential for brain regeneration after injuries, particularly stem cell treatment for hippocampal-related diseases.

The HPV16 E6, E7/miR-23b-3p/ICAT signaling axis promotes proliferation, migration, invasion and EMT of cervical cancer cells

Cervical cancer (CC) remains one of the most common female malignancies, with higher incidence and mortality rates. more than 99% of CCs are associated with persistent infection with high-risk human papillomavirus. In view of the growing evidence that HPV 16 E6 and E7, two key oncoproteins encoded by HPV 16, regulate the expression of many other multifunctional genes and downstream effectors that contribute to the development of CC. Herein, we undertook a comprehensive effort into how HPV16 E6, E7 oncogenes affect the progression of CC cells. Previous studies have shown that ICAT expression was significantly increased in CC and had a pro-cancer effect. We observed that knockdown of HPV16 E6, E7 expression in SiHa and CasKi cells resulted in significant inhibition of ICAT expression and upregulation of miR-23b-3p expression. Besides, dual luciferase assays confirmed that ICAT was a target gene of miR-23b-3p, and negatively modulated by miR-23b-3p. Functional experiments showed that the overexpression of miR-23b-3p suppressed malignant behaviors of CC cells, such as migration, invasion and EMT. The overexpression of ICAT counteracted the suppressive effect of miR-23b-3p on HPV16-positive CC cells. Furthermore, after the knockdown of HPV16 E6 and E7, the inhibition of miR-23b-3p could increase the ICAT expression and rescue the siRNA HPV16 E6, E7-mediated suppressive impact on the aggressiveness of SiHa and CaSki cells. Collectively, our findings uncover that HPV16 E6, E7/miR-23b-3p/ ICAT axis plays an important role in HPV16-positive CC pathogenesis, which may serve as a promising therapeutic target for HPV16-associated CC.

API-2-Induced Cell Migration Is Overcome by Small Molecular Approaches Inhibiting β-Catenin

Frequent mutation of APC (90%) in advanced colorectal cancer (CRC) results in the simultaneous activation of Wnt/β-catenin and AKT signaling pathways, and the current therapeutic limitations of the AKT inhibitors for treating CRC patients are nuclear β-catenin-induced EMT and bypassing apoptosis. In this study, we discover that the combinatorial treatment of an AKT inhibitor and KY1022, a β-catenin destabilizer, effectively overcomes the current limitations of API-2, an AKT inhibitor, by reducing nuclear β-catenin. Taken together, we demonstrate that the simultaneous suppression of Wnt/β-catenin with the AKT signaling pathways is an ideal strategy for suppressing the AKT-inhibitor-mediated metastasis and for maximizing the therapeutic effects of AKT inhibitors.

Inhibition of phospholipase D1 induces immunogenic cell death and potentiates cancer immunotherapy in colorectal cancer

Phospholipase D (PLD) is a potential therapeutic target against cancer. However, the contribution of PLD inhibition to the antitumor response remains unknown. We developed a potent and selective PLD1 inhibitor based on computer-aided drug design. The inhibitor enhanced apoptosis in colorectal cancer (CRC) cells but not in normal colonic cells, and in vitro cardiotoxicity was not observed. The inhibitor downregulated the Wnt/β-catenin signaling pathway and reduced the migration, invasion, and self-renewal capacity of CRC cells. In cancer, therapeutic engagement of immunogenic cell death (ICD) leads to more effective responses by eliciting the antitumor immunity of T cells. The CRC cells treated with the inhibitor showed hallmarks of ICD, including downregulation of “do not eat-me” signals (CD24, CD47, programmed cell death ligand 1 [PD-L1]), upregulation of “eat-me” signal (calreticulin), release of high-mobility group Box 1, and ATP. PLD1 inhibition subsequently enhanced the phagocytosis of cancer cells by macrophages through the surface expression of costimulatory molecules; as a result, the cancer cells were more susceptible to cytotoxic T-cell-mediated killing. Moreover, PLD1 inhibition attenuated colitis-associated CRC and orthotopically injected tumors, probably by controlling multiple pathways, including Wnt signaling, phagocytosis checkpoints, and immune signaling. Furthermore, combination therapy with a PLD1 inhibitor and an anti-PD-L1 antibody further enhanced tumor regression via immune activation in the tumor environment. Collectively, in this study, PLD1 was identified as a critical regulator of the tumor microenvironment in colorectal cancer, suggesting the potential of PLD1 inhibitors for cancer immunotherapy based on ICD and immune activation. PLD1 inhibitors may act as promising immune modulators in antitumor treatment via ICD.

A novel drug that can inhibit an enzyme involved in colorectal cancer progression shows promise in trials on mouse models. The phospholipase D1 (PLD1) enzyme reinforces a critical signaling pathway that promotes cancer progression and drug resistance. Using computer-aided drug design, South Korean researchers led by Do Sik Min and Gyoonhee Han at Yonsei University in Incheon and Seoul, respectively, have developed a drug that specifically binds to and inhibits PLD1. In trials, the researchers observed downregulation of PLD1’s associated signaling pathway, and reductions in the ability of colorectal cancer cells to migrate, invade and replicate. The drug suppressed the cancer cells’ “don’t-eat-me” signals and upregulated “eat-me” signals, triggering improved responses from the immune system. The drug was even more effective when used in combination with an immunotherapy agent.

Phospholipase D1 promotes cervical cancer progression by activating the RAS pathway

This study aimed to further investigate the effect of PLD1 on the biological characteristics of human cervical cancer (CC) cell line, CASKI and the potential related molecular mechanism. CRISPR/Cas9 genome editing technology was used to knock out the PLD1 gene in CASKI cells. Cell function assays were performed to evaluate the effect of PLD1 on the biological function of CASKI cells in vivo and in vitro. A PLD1‐overexpression rescue experiment in these knockout cells was performed to further confirm its function. Two PLD1‐knockout CASKI cell lines (named PC‐11 and PC‐40, which carried the ins1/del4 mutation and del1/del2/ins1 mutation, respectively), were constructed by CRISPR/Cas9. PLD1 was overexpressed in these knockout cells (named PC11‐PLD1 and PC40‐PLD1 cells), which rescued the expression of PLD1 by approximately 71.33% and 74.54%, respectively. In vivo, the cell function assay results revealed that compared with wild‐type (WT)‐CASKI cells, the ability of PC‐11 and PC‐40 cells to proliferate, invade and migrate was significantly inhibited. The expression of H‐Ras and phosphorylation of Erk1/2 (p‐Erk1/2) was decreased in PC‐11 and PC‐40 cells compared with WT‐CASKI cells. PC‐11 and PC‐40 cells could sensitize CASKI cells to cisplatin. More importantly, the proliferation, migration and invasion of PC11‐PLD1 and PC40‐PLD1 cells with PLD1 overexpression were significantly improved compared with those of the two types of PLD1 knockout cells. The sensitivity to cisplatin was decreased in PC11‐PLD1 and PC40‐PLD1 cells compared with PC‐11 and PC‐40 cells. In vivo, in the PC‐11 and PC‐40 tumour groups, tumour growth was significantly inhibited and tumour weight (0.95 ± 0.27 g and 0.66 ± 0.43 g vs. 1.59 ± 0.67 g, p = 0.0313 and 0.0108) and volume (1069.41 ± 393.84 and 1077.72 mm³ ± 815.07 vs. 2142.94 ± 577.37 mm³, p = 0.0153 and 0.0128) were significantly reduced compared to those in the WT‐CASKI group. Tumour differentiation of the PC‐11 and PC40 cells was significantly better than that of the WT‐CASKI cells. The immunohistochemistry results confirmed that the expression of H‐Ras and p‐Erk1/2 was decreased in PC‐11 and PC‐40 tumour tissues compared with WT‐CASKI tumour tissues. PLD1 promotes CC progression by activating the RAS pathway. Inhibition of PLD1 may serve as an attractive therapeutic modality for CC.

MiR-21 regulating PVT1/PTEN/IL-17 axis towards the treatment of infectious diabetic wound healing by modified GO-derived biomaterial in mouse models

BACKGROUND

Diabetic foot ulcer (DFU), persistent hyperglycemia and inflammation, together with impaired nutrient and oxygen deficiency, can present abnormal angiogenesis following tissue injury such that these tissues fail to heal properly. It is critical to design a new treatment method for DFU patients with a distinct biomechanism that is more effective than current treatment regimens.

METHOD

Graphene oxide (GO) was combined with a biocompatible polymer as a kind of modified GO-based hydrogel. The characterization of our biomaterial was measured in vitro. The repair efficiency of the biomaterial was evaluated in the mouse full-skin defect models. The key axis related to diabetic wound (DW) was identified and investigated using bioinformatics analyses and practical experiments.

RESULT

In the study, we found that our modified GO-based wound dressing material is a promising option for diabetic wound. Secondly, our biomaterial could enhance the secretion of small EVs (sEVs) with more miR-21 by adipose-derived mesenchymal stem cells (AD-MSCs). Thirdly, the PVT1/PTEN/IL-17 axis was found to be decreased to promote DFU wound healing by modifying miR-21 with the discovery of PVT1 as a critical LncRNA by bioinformatics analysis and tests.

CONCLUSION

These findings could aid in the development of clinical care strategies for DFU wounds.

Downregulated Wnt2B Expression Suppresses Proliferation, Invasion, and Angiogenesis of Ovarian Cancer Cells Through Inhibiting the Wnt/β-Catenin Signaling Pathway

Ovarian cancer (OC) is known to be the most malignant gynecologic cancers. Wnt2B, a member of the Wnt family, plays a critical role in tumor development. However, the effect of Wnt2B on the occurrence and development of OC remains largely uncharacterized. In this study, immunohistochemistry assay indicated that Wnt2B was increased in our study cohort (OC). In addition, the expression of Wnt2B was positively correlated with TNM stages and metastasis of OC patients. Wnt2B markedly mediated the regulation of OC proliferation, invasion, and angiogenesis. Moreover, Wnt2B knockdown inactivated the Wnt/β-catenin signaling pathway. More importantly, the Wnt/β-catenin signaling pathway activator LiCl reversed the effect of Wnt2B knockdown on OC cell proliferation, angiogenesis, and invasion. Our data indicated that Wnt2B silencing could inhibit the proliferation, invasion, and angiogenesis of OC cells through downregulating the activity of Wnt/β-catenin pathway.

Harmine Hydrochloride Triggers G2/M Cell Cycle Arrest and Apoptosis in HCT116 Cells through ERK and PI3K/AKT/mTOR Signaling Pathways

Colorectal carcinoma (CRC) is one of the most common and aggressive malignant carcinomas. There is a pressing need to develop naturally derived novel drugs with minimal side effects for treatment of CRC. In this study, we aimed to investigate the anticancer effects of harmine hydrochloride (HMH), a hydrophilic and stable substance that is easily absorbed by tissues and similar to harmine, and the underlying mechanism of action in human CRC HCT116 cells. HMH inhibited the growth, colony formation, and migration ability of HCT116 cells. Additionally, HMH induced G2 cell cycle arrest by reducing expression of p-cdc2, cdc2, and cyclin B1, proteins that regulate the G2/M phase, and expression of Rb, a protein that regulates cell proliferation, in a dose-dependent manner. HMH mediated apoptosis by downregulating expression of apoptotic proteins (such as caspase-3, caspase-9, and PARP) and the anti-apoptotic protein Bcl-2 and by inducing expression of Bax, a pro-apoptotic protein. Furthermore, HMH reduced the levels of p-ERK, p-PI3K, p-AKT, and p-mTOR in HCT116 cells, and significantly inhibited p-ERK and p-AKT expression in cells treated with of HMH and PD98059, an ERK inhibitor, or LY294002, an AKT inhibitor (P<0.05 and P<0.01). These results demonstrate the inhibi-tory effect of HMH on cell proliferation and migration through inducing apoptosis by inhibiting ERK and PI3K/AKT/mTOR signaling pathways, indicating its potential therapeutic applications in CRC.

Targeting PI3K/Akt signal transduction for cancer therapy

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays a crucial role in various cellular processes and is aberrantly activated in cancers, contributing to the occurrence and progression of tumors. Examining the upstream and downstream nodes of this pathway could allow full elucidation of its function. Based on accumulating evidence, strategies targeting major components of the pathway might provide new insights for cancer drug discovery. Researchers have explored the use of some inhibitors targeting this pathway to block survival pathways. However, because oncogenic PI3K pathway activation occurs through various mechanisms, the clinical efficacies of these inhibitors are limited. Moreover, pathway activation is accompanied by the development of therapeutic resistance. Therefore, strategies involving pathway inhibitors and other cancer treatments in combination might solve the therapeutic dilemma. In this review, we discuss the roles of the PI3K/Akt pathway in various cancer phenotypes, review the current statuses of different PI3K/Akt inhibitors, and introduce combination therapies consisting of signaling inhibitors and conventional cancer therapies. The information presented herein suggests that cascading inhibitors of the PI3K/Akt signaling pathway, either alone or in combination with other therapies, are the most effective treatment strategy for cancer.

miR-29a-3p promotes migration and invasion in ameloblastoma via Wnt/β-catenin signaling by targeting catenin beta interacting protein 1

BACKGROUND

Ameloblastoma (AB) is a common epithelial odontogenic tumor. The Wnt/β-catenin pathway has been found to be related to AB invasion.

METHODS

The alteration expression of microRNAs (miRNAs) and messenger RNAs (mRNAs) was performed by miRNA and mRNA microarray analysis and validated by quantitative real-time polymerase chain reaction (RT-PCR). The effects of miR-29a-3p on migration and invasion in AB cells were evaluated by a transwell assay. Bioinformatic prediction was conducted using the miRSystem and validated by quantitative RT-PCR, western blot, and a luciferase reporter assay.

RESULTS

miR-29a-3p was overexpressed in AB tissues, which promoted the migration and invasion of AB cells in vitro. Catenin beta interacting protein 1 (CTNNBIP1), a negative regulator of the Wnt/β-catenin pathway, was predicted to be a target of miR-29a-3p. miR-29a-3p inhibited the expression of CTNNBIP1 and promoted the expression of the downstream molecules of the Wnt/β-catenin pathway.

CONCLUSIONS

miR-29a-3p promoted migration and invasion in AB via Wnt/β-catenin signaling by targeting CTNNBIP1.

MiR-486-3p promotes osteogenic differentiation of BMSC by targeting CTNNBIP1 and activating the Wnt/β-catenin pathway

BACKGROUND

Dysfunction in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) leads to bone loss/osteoporosis. The catenin beta interacting protein 1 (CTNNBIP1) is an inhibitor of Wnt/β-catenin signaling, whose role in osteogenesis remains elusive. This study aimed to reveal the effects of miR-486-3p/CTNNBIP1 in osteogenesis.

METHODS

Bone marrow samples from healthy individuals and osteoporosis patients and mice with sham or ovariectomy (OVX) surgeries were collected. Levels of CTNNBIP1 and miR-486-3p were assessed. A dual-luciferase reporter assay was used to confirm the interactions between CTNNBIP1 and miR-486-3p. MiR-486-3p mimics/inhibitor or CTNNBIP1 overexpression lentiviruses were transfected to human BMSCs (hBMSCs) and an osteogenic assay was performed. Alizarin red S (ARS) and Alkaline phosphatase (ALP) intensity and expression of osteogenic genes Runx2, Alp, Cola1 and Bglap were measured. Key proteins in the Wnt/β-catenin pathway including active β-catenin, Bcl-2, and Cyclin D1 were assessed.

RESULTS

CTNNBIP1 was upregulated while miR-486-3p was downregulated in osteoporosis patients and OVX mice. CTNNBIP1 was confirmed as a target of miR-486-3p. MiR-486-3p overexpression promoted, while miR-486-3p knockdown suppressed, osteogenic differentiation and Wnt/β-catenin signaling. Rescue experiments confirmed the negative effects of CTNNBIP1 overexpression on osteoblastic differentiation and that miR-486-3p mimics could reverse canonical Wnt signaling.

CONCLUSION

This study demonstrated that miR-486-3p targets CTNNBIP1, thus activating the Wnt/β-catenin signaling pathway to promote osteogenesis of BMSCs.

An Update on the Potential Roles of E2F Family Members in Colorectal Cancer

Colorectal cancer (CRC) is a major health burden worldwide, and thus, optimised diagnosis and treatments are imperative. E2F transcription factors (E2Fs) are a family of transcription factors consisting of eight genes, contributing to the oncogenesis and development of CRC. Importantly, E2Fs control not only the cell cycle but also apoptosis, senescence, DNA damage response, and drug resistance by interacting with multiple signaling pathways. However, the specific functions and intricate machinery of these eight E2Fs in human CRC remain unclear in many respects. Evidence on E2Fs and CRC has been scattered on the related regulatory genes, microRNAs (miRNAs), and competing endogenous RNAs (ceRNAs). Accordingly, some drugs targeting E2Fs have been transferred from preclinical to clinical application. Herein, we have systemically reviewed the current literature on the roles of various E2Fs in CRC with the purpose of providing possible clinical implications for patient diagnosis and prognosis and future treatment strategy design, thereby furthering the understanding of the E2Fs.

A recombinant Chinese measles virus vaccine strain rMV-Hu191 inhibits human colorectal cancer growth through inducing autophagy and apoptosis regulating by PI3K/AKT pathway

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The recombinant Chinese measles virus vaccine strain rMV-Hu191 induced efficient infection and oncolytic effects in human CRC both in vitro and in vivo.

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rMV-Hu191 induced the caspase-dependent apoptosis and complete autophagy in CRC cells.

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Autophagy served as a protective role in human CRC cells’ apoptosis induced by rMV-Hu191.

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rMV-Hu191-induced autophagy and apoptosis were regulated by the PI3K/AKT signaling pathway in human CRC.

The potential therapeutic effects of oncolytic measles virotherapy have been verified against plenty of malignancies. However, the oncolytic effects and underlying mechanisms of the recombinant Chinese measles virus vaccine strain Hu191 (rMV-Hu191) against human colorectal cancer (CRC) remain elusive. In this study, the antitumor effects of rMV-Hu191 were evaluated in CRC both in vitro and in vivo. From our data, rMV-Hu191 induced remarkably caspase-dependent apoptosis and complete autophagy in vitro. In mice bearing CRC xenografts, tumor volume was remarkably suppressed and median survival was prolonged significantly with intratumoral treatment of rMV-Hu191. To gain further insight into the relationship of rMV-Hu191-induced apoptosis and autophagy, we utilized Rapa and shATG7 to regulate autophagy. Our data suggested that autophagy was served as a protective role in rMV-Hu191-induced apoptosis in CRC. PI3K/AKT signaling pathway as one of the common upstream pathways of apoptosis and autophagy was activated in CRC after treatment with rMV-Hu191. And inhibition of PI3K/AKT pathway using LY294002 was accompanied by enhanced apoptosis and decreased autophagy which suggested that PI3K/AKT pathway promoted rMV-Hu191-induced autophagy and inhibited rMV-Hu191-induced apoptosis. This is the first study to demonstrate that rMV-Hu191 could be used as a potentially effective therapeutic agent in CRC treatment. As part of the underlying cellular mechanisms, apoptosis and autophagy were involved in the oncolytic effects generated by rMV-Hu191. And the cross-talk between these two processes and the PI3K/AKT signaling pathway was well identified.

Hypoxia-induced cofilin 1 promotes hepatocellular carcinoma progression by regulating the PLD1/AKT pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is the fourth fatal malignant tumour type worldwide. However, the exact molecular mechanism involved in HCC progression remains unclear.

METHODS

Three pairs of HCC and matched portal vein tumour thrombus (PVTT) tissue samples were analysed by isobaric tags for relative and absolute quantification (iTRAQ) assay to investigate the differentially expressed proteins. Real-time quantitative PCR, immunostaining, and immunoblotting were performed to detect cofilin 1 (CFL1) in HCC and non-tumour tissues. CCK8 and EdU, and Transwell assays, respectively, determined cell proliferation, migration, and invasion of HCC cells. Further, subcutaneous and tail vein injection were performed in nude mice for investigating HCC growth and lung metastasis in vivo. Regulatory effect of hypoxia-inducible factor-1α (HIF-1α) on CFL1 was confirmed by chromatin immunoprecipitation (ChIP) assay. Finally, interaction between CFL1 and phospholipase D1 (PLD1) was studied using immunoprecipitation (IP) assay.

RESULTS

The iTRAQ analysis identified expression of CFL1 to be significantly upregulated in PVTT than in HCC tissues. Increased expression of CFL1 was closely associated with unfavourable clinical features, and was an independent risk predictor of overall survival in HCC patients. The knockdown of CFL1 inhibited cell growth viability, invasiveness, and epithelial-mesenchymal transformation (EMT) in HCC cells. Furthermore, CFL1 silencing significantly suppressed the growth and lung metastasis of HCC cells in nude mice. Next, HIF-1α directly regulated CFL1 transcription by binding to the hypoxia-responsive element (HRE) in the promoter. Moreover, we disclosed the interaction between CFL1 and PLD1 in HCC cells using IP assay. Mechanistically, CFL1 maintained PLD1 expression by repressing ubiquitin-mediated protein degradation, thereby activating AKT signalling in HCC cells. Notably, the CFL1/PLD1 axis was found mediating the hypoxia-induced activation of the AKT pathway and EMT.

CONCLUSION

The analysis suggests that hypoxia-induced CFL1 increases the proliferation, migration, invasion, and EMT in HCC by activating the PLD1/AKT pathway.

MiR-122-5p and miR-326-3p promote cadmium-induced NRK-52E cell apoptosis by downregulating PLD1

Cadmium is a toxic heavy metal distributed broadly in the environment and manufactory industry. Long-term exposure to cadmium, considered as a risk for kidney injury, leads to chronic kidney disease eventually. Phospholipase D1 (PLD1) promotes cell proliferation and inhibits apoptosis, and might be involved in cadmium-induced kidney injury. In this study, we used miRNA microarray assays and bioinformatics analysis to identify miRNAs, which may regulate PLD1 expression and exert an impact on cadmium-induced kidney injury. MiR-122-5p and miR-326-3p，selected as candidates, were explored for their regulatory functions in kidney injury, using NRK-52E cells. Both of these two miRNAs exhibited higher expression in kidneys of SD rats after exposure to cadmium for 6 weeks. Cadmium treatment also increased miR-122-5p and miR-326-3p and decreased PLD1 in NRK-52E cells. Both of miR-122-5p and miR-326-3p could downregulate PLD1 expression through targeting its 3'UTR and enhance cadmium-induced apoptosis, while inhibiting either of these two miRNAs could reverse such effects. In conclusion, our results suggest that miR-122-5p and miR-326-3p might enhance cadmium-induced NRK-52E cell apoptosis through downregulating PLD1 expression.

Blockade of PLD1 potentiates the antitumor effects of bortezomib in multiple myeloma cells by inhibiting the mTOR/NF-κB signal pathway

OBJECTIVE

Phospholipase D1 (PLD1) is an enzyme of the phospholipase D (PLD) superfamily. It is involved in the occurrence of various tumors. However, its role in multiple myeloma (MM) remained undefined. This study aimed to investigate the mechanism of PLD1 in the therapy of myeloma disease.

MATERIAL AND METHODS

Cell lines U266 and H929 were treated with PLD1 specific inhibitor VU0359595 combined bortezomib, a proteasome inhibitor. Their effects on MM cell proliferation, apoptosis, and relevant signal pathways of apoptosis were determined by cell counting kit-8 (CCK-8), real-time polymerase reaction chain (RT-PCR), ATP assay, and western blot.

RESULTS

PLD1 was highly expressed in U266 and H929 cells. VU0359595 didn't affect the proliferation and apoptosis of MM cells. However, VU0359595 could enhance growth inhibition, decreasing mitochondrial membrane potentials (MMPs) and ATP levels of bortezomib treated MM cells. VU0359595 also strengthened bortezomib-induced apoptosis via activating caspase-8, caspase-9, caspase-3; and down-regulating the expressions of anti-apoptosis proteins BCL-2. In addition, the bortezomib-induced cytotoxicity on MM cells was significantly augmented by VU0359595 through efficient suppression of the mTOR/NF-κB signal pathway.

CONCLUSION

PLD1 inhibition can remarkably exert antitumor effects with bortezomib on MM, which is a novel potentially targeting therapeutic agent, especially for drug-resistant MM patients.

Structural insights into phospholipase D function

Phospholipase D (PLD) and its metabolic active product phosphatidic acid (PA) engage in a wide range of physiopathologic processes in the cell. PLDs have been considered as a potential and promising drug target. Recently, the crystal structures of PLDs in mammalian and plant have been solved at atomic resolution. These achievements allow us to understand the structural differences among different species of PLDs and the functions of their key domains. In this review, we summarize the sequence and structure of different species of PLD isoforms, and discuss the structural mechanisms for PLD interactions with their binding partners and the functions of each key domain in the regulation of PLDs activation and catalytic reaction.

Human La Protein: An RNA-Binding Protein Involved in Ovarian Cancer Development and Multidrug Resistance

Multidrug resistance is the main cause of chemotherapy failure and death in patients with advanced ovarian cancer. Drug resistance is a problem that must be solved to improve the survival rate of patients with advanced ovarian cancer. The RNA-binding protein La and the La-related protein family are highly expressed in various malignant tumors, including ovarian cancer. This article reviews the mechanisms of La protein in tumorigenesis, development, and drug resistance. High La protein expression in tumor cells promotes tumor proliferation, invasion, and migration; disrupts cell cycle; and inhibits tumor cell apoptosis caused by chemotherapeutic drugs through various pathways, resulting in chemotherapy resistance in ovarian cancer. Further study of the role of La protein in ovarian cancer multidrug resistance may be conducive to the development of human La protein-specific inhibitors that suppress ovarian cancer drug resistance.

5-FU promotes stemness of colorectal cancer via p53-mediated WNT/β-catenin pathway activation

5-Fluorouracil (5-FU) remains the first-line treatment for colorectal cancer (CRC). Although 5-FU initially de-bulks the tumor mass, recurrence after chemotherapy is the barrier to effective clinical outcomes for CRC patients. Here, we demonstrate that p53 promotes WNT3 transcription, leading to activation of the WNT/β-catenin pathway in Apc^Min/+/Lgr5^EGFP mice, CRC patient-derived tumor organoids (PDTOs) and patient-derived tumor cells (PDCs). Through this regulation, 5-FU induces activation and enrichment of cancer stem cells (CSCs) in the residual tumors, contributing to recurrence after treatment. Combinatorial treatment of a WNT inhibitor and 5-FU effectively suppresses the CSCs and reduces tumor regrowth after discontinuation of treatment. These findings indicate p53 as a critical mediator of 5-FU-induced CSC activation via the WNT/β-catenin signaling pathway and highlight the significance of combinatorial treatment of WNT inhibitor and 5-FU as a compelling therapeutic strategy to improve the poor outcomes of current 5-FU-based therapies for CRC patients.

Phospholipase D1 and D2 Synergistically Regulate Thrombus Formation

Previously, we reported that phospholipase D1 (PLD1) and PLD2 inhibition by selective PLD1 and PLD2 inhibitors could prevent platelet aggregation in humans, but not in mice. Moreover, only the PLD1 inhibitor, but not PLD2 inhibitor, could effectively prevent thrombus formation in mice, indicating that PLD might play different roles in platelet function in humans and mice. Although PLD1 and PLD2 were reported to be implicated in thrombotic events, the role of PLD in mice remains not completely clear. Here, we investigated the role of PLD1 and PLD2 in acute pulmonary thrombosis and transient middle cerebral artery occlusion-induced brain injury in mice. The data revealed that inhibition of PLD1, but not of PLD2, could partially prevent pulmonary thrombosis-induced death. Moreover, concurrent PLD1 and PLD2 inhibition could considerably increase survival rate. Likewise, inhibition of PLD1, but not PLD2, partially improved ischemic stroke and concurrent inhibition of PLD1, and PLD2 exhibited a relatively better protection against ischemic stroke, as evidenced by the infarct size, brain edema, modified neurological severity score, rotarod test, and the open field test. In conclusion, PLD1 might play a more important role than PLD2, and both PLD1 and PLD2 could act synergistically or have partially redundant functions in regulating thrombosis-relevant events.

Transcriptional Regulation of Wnt/β-Catenin Pathway in Colorectal Cancer

The Wnt/β-catenin signaling pathway exerts integral roles in embryogenesis and adult homeostasis. Aberrant activation of the pathway is implicated in growth-associated diseases and cancers, especially as a key driver in the initiation and progression of colorectal cancer (CRC). Loss or inactivation of Adenomatous polyposis coli (APC) results in constitutive activation of Wnt/β-catenin signaling, which is considered as an initiating event in the development of CRC. Increased Wnt/β-catenin signaling is observed in virtually all CRC patients, underscoring the importance of this pathway for therapeutic intervention. Prior studies have deciphered the regulatory networks required for the cytoplasmic stabilisation or degradation of the Wnt pathway effector, β-catenin. However, the mechanism whereby nuclear β-catenin drives or inhibits expression of Wnt target genes is more diverse and less well characterised. Here, we describe a brief synopsis of the core canonical Wnt pathway components, set the spotlight on nuclear mediators and highlight the emerging role of chromatin regulators as modulators of β-catenin-dependent transcription activity and oncogenic output.

Phospholipase D1 inhibition sensitizes glioblastoma to temozolomide and suppresses its tumorigenicity

Resistance of glioblastoma to the chemotherapeutic compound temozolomide is associated with the presence of glioblastoma stem cells in glioblastoma and is a key obstacle for the poor prognosis of glioblastoma. Here, we show that phospholipase D1 is elevated in CD44^High glioblastoma stem cells and in glioblastoma, especially recurring glioblastoma. Phospholipase D1 elevation positively correlated with the level of CD44 and poor prognosis in glioblastoma patients. Temozolomide significantly upregulated the expression of phospholipase D1 in the low and moderate CD44 populations of glioblastoma stem cells, but not in the CD44^High population in which phospholipase D1 is highly expressed. Phospholipase D1 conferred resistance to temozolomide in CD44^High glioblastoma stem cells and increased their self‐renewal capacity and maintenance. Phospholipase D1 expression significantly correlated with levels of temozolomide resistance factors, which were suppressed by microRNA‐320a and ‐4496 induced by phospholipase D1 inhibition. Genetic and pharmacological targeting of phospholipase D1 attenuated glioblastoma stem cell‐derived intracranial tumors of glioblastoma using the microRNAs, and improved survival. Treatment solely with temozolomide produced no benefits on the glioblastoma, whereas in combination, phospholipase D1 inhibition sensitized glioblastoma stem cells to temozolomide and reduced glioblastoma tumorigenesis. Together, these findings indicate that phospholipase D1 inhibition might overcome resistance to temozolomide and represents a potential treatment strategy for glioblastoma. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Causal Disturbance Analysis: A Novel Graph Centrality Based Method for Pathway Enrichment Analysis

Pathway enrichment analysis models (PEM) are the premier methods for interpreting gene expression profiles from high-throughput experiments. PEM often use a priori background knowledge to infer the underlying biological functions and mechanisms. A shortcoming of standard PEM is their disregarding of interactions for simplicity, which potentially results in partial and inaccurate inference. In this study, we introduce a graph-based PEM, namely Causal Disturbance Analysis (CADIA), that leverages gene interactions to quantify the topological importance of genes' expression profiles in pathways organizations. In particular, CADIA uses a novel graph centrality model, namely Source/Sink, to measure the topological importance. Source/Sink Centrality quantifies a gene's importance as a receiver and a sender of biological information, which allows for prioritizing the genes that are more likely to disturb a pathways functionality. CADIA infers an enrichment score for a pathway by deriving statistical evidence from Source/Sink centrality of the differentially expressed genes and combines it with classical over-representation analysis. Through real-world experimental and synthetic data evaluations, we show that CADIA can uniquely infer critical pathway enrichments that are not observable through other PEM. Our results indicate that CADIA is sensitive towards topologically central gene-level changes that and provides an informative framework for interpreting high-throughput data.

Phospholipase D1 is upregulated by vorinostat and confers resistance to vorinostat in glioblastoma

Glioblastoma (GBM) is an aggressive brain tumor and drug resistance remains a major barrier for therapeutics. Epigenetic alterations are implicated in GBM pathogenesis, and epigenetic modulators including histone deacetylase (HDAC) inhibitors are exploited as promising anticancer therapies. Here, we demonstrate that phospholipase D1 (PLD1) is a transcriptional target of HDAC inhibitors and confers resistance to HDAC inhibitor in GBM. Treatment of vorinostat upregulates PLD1 through PKCζ‐Sp1 axis. Vorinostat induces dynamic changes in the chromatin structure and transcriptional machinery associated with PLD1 promoter region. Cotreatment of vorinostat with PLD1 inhibitor further attenuates invasion, angiogenesis, colony‐forming capacity, and self‐renewal capacity, compared with those of either treatment. PLD1 inhibitor overcomes resistance to vorinostat in GBM cells intracranial GBM tumors. Our finding provides new insight into the role of PLD1 as a target of resistance to vorinostat, and PLD1 inhibitor might provide the basis for therapeutic combinations with improved efficacy of HDAC inhibitor.

Small molecule-induced simultaneous destabilization of β-catenin and RAS is an effective molecular strategy to suppress stemness of colorectal cancer cells

BACKGROUND

Cancer stem cells (CSCs), the major driver of tumorigenesis, is a sub-population of tumor cells responsible for poor clinical outcomes. However, molecular mechanism to identify targets for controlling CSCs is poorly understood.

METHODS

Gene Set Enrichment Analyses (GSEA) of Wnt/β-catenin and RAS signaling pathways in stem-like subtype of colorectal cancer (CRC) patients were performed using two gene expression data set. The therapeutic effects of destabilization of β-catenin and RAS were tested by treatment of small molecule KYA1797K using CRC patient derived cells.

RESULTS

Treatment with KYA1797K, a small molecule that destabilizes both β-catenin and RAS via Axin binding, effectively suppresses the stemness of CSCs as shown in CRC spheroids and small intestinal tumors of Apc^Min/+/K-Ras^G12DLA2 mice. Moreover, KYA1797K also suppresses the stemness of cells in CRC patient avatar model systems, such as patient-derived tumor organoids (PDTOs) and patient-derived tumor xenograft (PDTX).

CONCLUSION

Our results suggest that destabilization of both β-catenin and RAS is a potential therapeutic strategy for controlling stemness of CRC cells. Video abstract.

Phospholipase D as a key modulator of cancer progression

The phospholipase D (PLD) family has a ubiquitous expression in cells. PLD isoforms (PLDs) and their hydrolysate phosphatidic acid (PA) have been demonstrated to engage in multiple stages of cancer progression. Aberrant expression of PLDs, especially PLD1 and PLD2, has been detected in various cancers. Inhibition or elimination of PLDs activity has been shown to reduce tumour growth and metastasis. PLDs and PA also serve as downstream effectors of various cell-surface receptors, to trigger and regulate propagation of intracellular signals in the process of tumourigenesis and metastasis. Here, we discuss recent advances in understanding the functions of PLDs and PA in discrete stages of cancer progression, including cancer cell growth, invasion and migration, and angiogenesis, with special emphasis on the tumour-associated signalling pathways mediated by PLDs and PA and the functional importance of PLDs and PA in cancer therapy.

Knockdown of long noncoding RNA PVT1 suppresses cell proliferation and invasion of colorectal cancer via upregulation of microRNA-214-3p

Long noncoding RNAs (lncRNAs) have been reported to be involved in the occurrence and tumorigenesis of numerous malignant cancers. Microarray expression profiles were used to screen colorectal cancer (CRC)-related differentially expressed genes and lncRNAs, which revealed that insulin receptor substrate 1 (IRS1) and lncRNA plasmacytoma variant translocation 1 (PVT1) were highly expressed in CRC. This study aimed to investigate the regulatory role of lncRNA PVT1 in CRC. Subcellular localization detected by fluorescence in situ hybridization identified that lncRNA PVT1 was primarily located in the cytoplasm. The interaction between lncRNA PVT1 and microRNA-214-3p (miR-214-3p) and IRS1 was predicted using the RNA22 website. Next the dual luciferase reporter gene assay, RNA pull-down, and RNA immunoprecipitation assays verified lncRNA PVT1 to be a competitive endogenous RNA (ceRNA) against miR-214-3p, and IRS1 was found to be a target of miR-214-3p. The expression pattern of lncRNA PVT1, miR-214-3p, IRS1, phosphoinositide 3-kinase (PI3K), and Akt was characterized in response to lncRNA PVT1 silencing or miR-214-3p upregulation. Meanwhile, their regulatory effects on cell proliferation, invasion, and apoptosis were detected in CRC cells. With increased levels of miR-214-3p and decreased levels of lncRNA PVT1 in CRC cells, the expression of phosphatidylinositol 3-kinase, putative (PI3K) and Akt was reduced, and consequently, the cell apoptosis was stimulated and cell proliferation and invasion were suppressed. All in all, lncRNA PVT1 competitively binds to miR-214-3p to upregulate the expression of IRS1 thus activating the PI3K/Akt signaling pathway, thus accelerating CRC progression. This study suggests that lncRNA PVT1 might be a potential target of therapeutic strategies for CRC treatment.NEW & NOTEWORTHY This study mainly suggests that long noncoding (lnc)RNA plasmacytoma variant translocation 1 (PVT1) is a downregulated lncRNA in colorectal cancer (CRC), accelerating CRC progression. Strikingly, lncRNA PVT1 acts as a competitive endogenous RNA against microRNA (miR)-214-3p, whereas miR-214-3p targets insulin receptor substrate 1, which draws a comprehensive picture of the potential molecular mechanisms of lncRNA PVT1 in CRC.

Integrated analyses of microRNA-29 family and the related combination biomarkers demonstrate their widespread influence on risk, recurrence, metastasis and survival outcome in colorectal cancer

Background

Emerging evidence has revealed miR-29 family as promising biomarkers for colorectal cancer (CRC), but their biomarker potential and molecular mechanisms remain poorly understood.

Methods

We performed a comprehensive meta-analysis to evaluate the biomarker performance of individual miR-29 and the related miRNA combination biomarkers. Meanwhile, we conducted an integrative bioinformatics analysis to unfold the underlying biological function of miR-29 and their relationship with CRC.

Results

Using miR-29 expression to diagnose CRC produced 0.82 area under the curve, 70% sensitivity and 81% specificity while the combination biomarkers based on miR-29 enhanced the diagnostic power with an AUC of 0.86, a sensitivity of 78% and a specificity of 91%. For the prognosis evaluation, patients with higher expression of miR-29 had better survival outcome (pooled HR 0.78; 95% CI 0.56–1.07). In addition, miR-29 has also been identified as potential biomarker for predicting recurrence and metastasis in CRC. Then the genes regulated by the miR-29 family were retrieved and found closely associated with the molecular pathogenesis of CRC according to the gene ontology and pathway analysis. Furthermore, hub nodes and significant modules were identified from the protein–protein interaction network constructed with miR-29 family targets, which were also confirmed highly involved in the establishment and development of CRC.

Conclusions

Current evidences suggest miR-29 family may become promising biomarkers for risk, recurrence, metastasis and survival outcome of CRC. Meanwhile our data highlight the potential clinical use of miRNA combination biomarkers. Nevertheless, further prospective studies are warranted before the application of the useful biomarkers in the clinical.

Knockdown of LncRNA SCAMP1 suppressed malignant biological behaviours of glioma cells via modulating miR-499a-5p/LMX1A/NLRC5 pathway

Dysregulation of long non‐coding RNAs (lncRNAs) confirm that it plays a crucial role in tumourigenesis and malignant progression of glioma. The present study demonstrated that LncRNA secretory carrier membrane protein 1 (SCAMP1) was up‐regulated and functioned as an oncogene in glioma cells. In addition, miR‐499a‐5p was down‐regulated meanwhile exerted tumour‐suppressive function in glioma cells. Subsequently, inhibition of SCAMP1 significantly restrained the cell proliferation, migration and invasion, as well as promoted apoptosis by acting as a molecular sponge of miR‐499a‐5p. Transcription factor LIM homeobox transcription factor 1, alpha (LMX1A) was overexpressed in glioma tissues and cells. Moreover, miR‐499a‐5p targeted LMX1A 3′‐UTR in a sequence‐specific manner. Hence, down‐regulation of SCAMP1 remarkably reduced the expression level of LMX1A, indicating that LMX1A participated in miR‐499a‐5p‐induced tumour‐suppressive effects on glioma cells. Furthermore, knockdown of LMX1A decreased NLR family, CARD domain containing 5 (NLRC5) mRNA and protein expression levels through directly binding to the NLRC5 promoter region. Down‐regulation of NLRC5 obviously inhibited malignant biological behaviours of glioma cells through attenuating the activity of Wnt/β‐catenin signalling pathway. In conclusion, our study clarifies that SCAMP1/miR‐499a‐5p/LMX1A/NLRC5 axis plays a critical role in modulating malignant progression of glioma cells, which provide a novel therapeutic strategy for glioma treatment.

mTOR Signalling in Head and Neck Cancer: Heads Up

The mammalian target of rapamycin (mTOR) signalling pathway is a central regulator of metabolism in all cells. It senses intracellular and extracellular signals and nutrient levels, and coordinates the metabolic requirements for cell growth, survival, and proliferation. Genetic alterations that deregulate mTOR signalling lead to metabolic reprogramming, resulting in the development of several cancers including those of the head and neck. Gain-of-function mutations in EGFR, PIK3CA, and HRAS, or loss-of-function in p53 and PTEN are often associated with mTOR hyperactivation, whereas mutations identified from The Cancer Genome Atlas (TCGA) dataset that potentially lead to aberrant mTOR signalling are found in the EIF4G1, PLD1, RAC1, and SZT2 genes. In this review, we discuss how these mutant genes could affect mTOR signalling and highlight their impact on metabolic processes, as well as suggest potential targets for therapeutic intervention, primarily in head and neck cancer.

Downregulation of Lgr6 inhibits proliferation and invasion and increases apoptosis in human colorectal cancer

The aim of the present study was to analyze the role of leucine‑rich repeat‑containing G‑protein coupled receptor 6 (Lgr6) in the proliferation and invasion of colorectal cancer (CRC) cells, and to investigate its possible mechanisms. The expression of Lgr6 in CRC tissues was observed by real time‑quantitative polymerase chain reaction and western blotting. Then cell viability, apoptosis and cell invasion was measured by MTT, flow cytometry or Matrigel‑Transwell system, respectively in CRC cells after transfected with Lgr6 siRNA or Lgr6 vector. Furthermore, the expression of apoptosis‑associated protein and PI3K/AKT signaling (phosphorylated‑PI3K, phosphorylated‑AKT, t‑PI3K, t‑AKT) were measured by real‑time PCR/or western blot analysis. The results demonstrated that the level of Lgr6 was higher in CRC tissues than that in adjacent tissues, and Lgr6 overexpression increased CRC proliferation, and invasion of CRC cells in vitro. Notably, suppressing the expression of Lgr6 in CRC cells increased the expression of B‑cell lymphoma-2 (Bcl‑2)‑associated X protein and caspase‑3, but decreased the expression of Bcl‑2 at the mRNA and protein levels. Lgr6 also had the ability to regulate the phosphoinositide 3‑kinase/AKT signaling pathway. It was concluded that Lgr6 has a tumor‑promoting role in the development of CRC, and may serve as a potential diagnostic and prognostic biomarker for the disease.