Downregulation of MYPT1 increases tumor resistance in ovarian cancer by targeting the Hippo pathway and increasing the stemness

Interaction of noncoding RNAs with hippo signaling pathway in cancer cells and cancer stem cells

The Hippo signaling pathway has a regulatory function in the organogenesis process and cellular homeostasis, switching the cascade reactions of crucial kinases acts to turn off/on the Hippo pathway, altering the downstream gene expression and thereby regulating proliferation, apoptosis, or stemness. Disruption of this pathway can lead to the occurrence of various disorders and different types of cancer. Recent findings highlight the importance of ncRNAs, such as microRNA, circular RNA, and lncRNAs, in modulating the Hippo pathway. Defects in ncRNAs can disrupt Hippo pathway balance, increasing tumor cells, tumorigenesis, and chemotherapeutic resistance. This review summarizes ncRNAs' inhibitory or stimulatory role in - Hippo pathway regulation in cancer and stem cells. Identifying the relation between ncRNAs and the components of this pathway could pave the way for developing new biomarkers in the treatment and diagnosis of cancers.

Clinical and molecular features of platinum resistance in ovarian cancer

Ovarian cancer is the most lethal of all the gynecological tumors despite remarkable advances in our understanding of its molecular biology. The cornerstone treatment remains cytoreductive surgery followed by platinum-based chemotherapy. Recently, the addition of targeted therapies, such as PARP inhibitors, as first-line maintenance has led to outstanding improvements, mainly in BRCA mutated and homologous recombination deficient tumors. However, a significant proportion of patients will experience recurrence, primarily due to platinum resistance, which ultimately result in fatality. Among these patients, primary platinum-resistant have a particularly dismal prognosis due to their low response to current available therapies, historical exclusion from clinical trials, and the absence of validated biomarkers. In this review, we discuss the concept of platinum resistance in ovarian cancer, the clinical and molecular characteristics of this resistance, and the current and new treatment options for these patients.

PPP1R14B-mediated phosphorylation enhances protein stability of RPS6KA1 to promote hepatocellular carcinoma tumorigenesis

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide with a poor clinical prognosis. Protein phosphatase 1 regulatory subunit 14B (PPP1R14B) is an unidentified protein phosphatase 1 regulatory subunit that is associated with the occurrence and development of various cancers. Recently, PPP1R14B was found to contribute to paclitaxel resistance and cell progression in triple-negative breast cancer; however, the role of PPP1R14B in HCC is unknown. Here, we found that PPP1R14B was highly expressed in HCC tissues, which suggested a poor prognosis. Knockdown of PPP1R14B significantly inhibited the survival and tumorigenic ability of HCC cells, while overexpression of PPP1R14B had the opposite effects. Mechanistically, Ribosomal Protein S6 Kinase type 1(RPS6KA1) was identified as the target gene of PPP1R14B. PPP1R14B maintained the stability and phosphorylation of RPS6KA1, and positively regulated activation of the AKT/NF-κB pathway. Importantly, PPP1R14B-deficient tumor suppression could be partially restored by wild-type but not phosphorylated mutant RPS6KA1. Taken together, these findings shed light on the function and mechanism of PPP1R14B in HCC progression, indicating PPP1R14B is a promising molecular target for the treatment of HCC.

CHD4 R975H mutant activates tumorigenic pathways and promotes stemness and M2-like macrophage polarization in endometrial cancer

Endometrial cancer (EC), one of the most prevalent carcinomas in females, is associated with increasing mortality. We identified the CHD4 R975H mutation as a high-frequency occurrence in EC patients through a comprehensive survey of EC databases. Computational predictions suggest that this mutation profoundly impacts the structural and functional integrity of CHD4. Functional assays revealed that the CHD4 R975H mutation enhances EC cell invasion, proliferation, and colony formation, promoting a cancer stem cell (CSC)-like phenotype. RNA-seq analysis of cells expressing CHD4 R975H mutant revealed a transcriptomic landscape marked by the activation of several cancer-promoting signaling pathways, including TNF-α signaling via NF-κB, KRAS, P53, mTOR, TGF-β, EGFR, Myc and growth factor signaling. Validation assays confirmed the activation of these pathways, further demonstrating that CHD4 R975H mutation induces stemness in EC cells and M2-like polarization of tumor-associated macrophages (TAMs). Our study elucidated the oncogenic role of CHD4 R975H mutation, highlighting its dual impact on facilitating cancer stemness and transforming TAMs into an immunosuppressive subtype. These findings contribute valuable insights into the molecular mechanisms driving EC progression and open avenues for targeted therapeutic interventions.

circ0005027 Acting as a ceRNA Affects the Malignant Biological Behavior of Hypopharyngeal Squamous Cell Carcinoma by Modulating miR-548c-3p/CDH1 Axis

Hypopharyngeal squamous cell carcinoma (HSCC) is a malignant tumor of head and neck. It was verified that circ0005027 was downregulated in HSCC tissues. Here, we aimed to investigate the function and specific regulatory mechanism of circ0005027 in HSCC. Ten pairs tissues of HSCC and adjacent para-cancer were collected. Reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR) measured circ0005027, miR-548c-3p, and Cadherin 1 (CDH1) mRNA expression. CCK-8 analyzed cell proliferation viability. Flow cytometry assay detected cell cycle and apoptosis rate. Clonal formation assay measured the clonal ability. Transwell detected cell invasion ability. Western blot was performed to detect CDH1, LAST1, p-LAST1, MST1, p-MST1, YAP1, p-YAP1, TAZ and p-TAZ protein level. Dual-luciferase, RIP and RNA pull-down assay identified the target relationship among circ0005027, miR-548c-3p and CDH1. circ0005027 was decreased in tissues and FaDu cells of HSCC. Overexpression of circ0005027 inhibited cell viability, G1-S transition, clonal formation, and invasion and increased cell apoptosis. circ0005027 acted as a ceRNA and decreased circ0005027 enhanced the malignant process of FaDu cells through sponging miR-548c-3p and inhibiting CDH1 expression. Overexpression of CDH1 activated YAP1/TAZ pathway and inhibited the growth of HSCC in vitro. circ0005027 might act as a potential biomarker for the progression and prognosis prediction in HSCC by regulating miR-548c-3p/CDH1/ YAP1/TAZ signaling pathway.

ARID1A restrains EMT and stemness of ovarian cancer cells through the Hippo pathway

Genes encoding subunits of SWI/SNF (BAF) chromatin‑remodeling complexes are recurrently mutated in a broad array of tumor types, and among the subunits, ARID1A is the most frequent target with mutations. In the present study, it was reported that ARID1A inhibits the epithelial‑mesenchymal transition (EMT) and stemness of ovarian cancer cells, accompanied by reduced cell viability, migration and colony formation, suggesting that ARID1A acts as a tumor suppressor in ovarian cancer. Mechanistically, ARID1A exerts its inhibitory effects on ovarian cancer cells by activating the Hippo signaling pathway. Conversely, the overexpression of a gain‑of‑function transcriptional co‑activator with PDZ‑binding motif (TAZ) mutant (TAZ‑Ser89) effectively reverses the effects induced by ARID1A. In addition, activation of Hippo signaling apparently upregulates ARID1A protein expression, whereas ectopic expression of TAZ‑Ser89 results in the markedly decreased ARID1A levels, indicating a feedback of ARID1A‑TAZ in regulating ovarian cancer cell EMT and stemness. Thus, the present study uncovered the role of ARID1A through the Hippo/TAZ pathway in modulating EMT and stemness of ovarian cancer cells, and providing with evidence that TAZ inhibitors could effectively prevent initiation and metastasis of ovarian cancer cases where ARID1A is lost or mutated.

Advances in ovarian tumor stem cells and therapy

Ovarian cancer is considered the most lethal among all gynecological malignancies due to its early metastatic dissemination, extensive spread, and malignant ascites. The current standard of care for advanced ovarian cancer involves a combination of cytoreductive surgery and chemotherapy utilizing platinum-based and taxane-based agents. Although initial treatment yields clinical remission in 70-80% of patients, the majority eventually develop treatment resistance and tumor recurrence. A growing body of evidence indicates the existence of cancer stem cells within diverse solid tumors, including ovarian cancer, which function as a subpopulation to propel tumor growth and disease advancement by means of drug resistance, recurrence, and metastasis. The presence of ovarian cancer stem cells is widely considered to be a significant contributor to the unfavorable clinical outcomes observed in patients with ovarian cancer, as they play a crucial role in mediating chemotherapy resistance, recurrence, and metastasis. Ovarian cancer stem cells possess the capacity to reassemble within the entirety of the tumor following conventional treatment, thereby instigating the recurrence of ovarian cancer and inducing resistance to treatment. Consequently, the creation of therapeutic approaches aimed at eliminating ovarian cancer stem cells holds great potential for the management of ovarian cancer. These cells are regarded as one of the most auspicious targets and mechanisms for the treatment of ovarian cancer. There is a pressing need for a comprehensive comprehension of the fundamental mechanisms of ovarian cancer's recurrence, metastasis, and drug resistance, alongside the development of effective strategies to overcome chemoresistance, metastasis, and recurrence. The implementation of cancer stem cell therapies may potentially augment the tumor cells' sensitivity to existing chemotherapy protocols, thereby mitigating the risks of tumor metastasis and recurrence, and ultimately improving the survival rates of ovarian cancer patients.

Identification of placenta-specific protein 1 (PLAC-1) expression on human PC-3 cell line-derived prostate cancer stem cells compared to the tumor parental cells

Placenta-specific protein 1 (PLAC-1) is a gene primarily expressed in the placenta and the testis. Interestingly, it is also found to be expressed in many solid tumors, and it is involved in malignant cell features. However, no evidence has been reported regarding the relationship between PLAC-1 and cancer stem cells (CSCs). In the current research, we explored the expression of the PLAC-1 molecule in prostate cancer stem cells (PCSCs) derived from the human PC-3 cell line. The enrichment of PCSCs was achieved using a three-dimensional cell culture technique known as the sphere-formation assay. To confirm the identity of PCSCs, we examined the expression of genes associated with stemness and pluripotency, such as SOX2, OCT4, Nanog, C-Myc, and KLF-4, as well as stem cell differentiation molecules like CD44 and CD133. These evaluations were conducted in both the PCSCs and the original tumor cells (parental cells) using real-time PCR and flow cytometry. Subsequently, we assessed the expression of the PLAC-1 molecule in both enriched cells and parental tumor cells at the gene and protein levels using the same techniques. The tumor cells from the PC-3 cell line formed spheroids with CSC characteristics in a non-adherent medium. The expression of SOX2, OCT4, Nanog, and C-Myc genes (p < 0.01), and the molecules CD44 and CD133 (p < 0.05) were significantly elevated in PCSCs compared to the parental cells. The expression of the PLAC-1 molecule in PCSCs showed a significant increase compared to the parental cells at both gene (p < 0.01) and protein (p < 0.001) levels. In conclusion, it was indicated for the first time that PLAC-1 is up-regulated in PCSCs derived from human PC-3 cell line. This study may propose PLAC-1 as a potential target in targeted therapies, which should be confirmed through further studies.

INHBA regulates Hippo signaling to confer 5-FU chemoresistance mediated by cellular senescence in colon cancer cells

Colon cancer has become a global public health challenge, and 5-Fluorouracil (5-FU) chemoresistance is a major obstacle in its treatment. Chemoresistance can be mediated by therapy-induced cellular senescence. This study intended to investigate mechanisms of INHBA (inhibin A) in 5-FU resistance mediated by cellular senescence in colon cancer. Bioinformatics analysis of INHBA expression in colon cancer tissues, survival analysis, and correlation analysis of cellular senescence markers were performed. The effects of INHBA on the biological characteristics and 5-FU resistance of colon cancer cells were examined through loss/gain-of-function and molecular assays. Finally, a xenograft mouse model was built to validate the mechanism of INHBA in vivo. INHBA was upregulated in colon cancer and was significantly positively correlated with cellular senescence markers uncoupling protein 2 (UCP-2), matrix metalloproteinase-1 (MMP-1), dense and erect panicle 1 (DEP1), and p21. Cellular senescence in colon cancer mediated 5-FU resistance. Downregulation of INHBA expression enhanced 5-FU sensitivity in colon cancer cells, inhibited cell proliferation, promoted apoptosis, increased the proportion of cells in G0/G1 phase, and it resulted in a lower proportion of senescent cells and lower levels of the cellular senescence markers interleukin 6 (IL-6) and interleukin 8 (IL-8). Analysis of whether to use the pathway inhibitor Verteporfin proved that INHBA facilitated colon cancer cell senescence and enhanced 5-FU chemoresistance via inactivation of Hippo signaling pathway, and consistent results were obtained in vivo. Collectively, INHBA conferred 5-FU chemoresistance mediated by cellular senescence in colon cancer cells through negative regulation of Hippo signaling.

Linc00662 sponges miR-15b-5p to promote hypopharyngeal squamous cell carcinoma progression by facilitating cancer stem cell-like phenotypes

Background: Long non-coding RNAs (lncRNAs) are associated with multiple head and neck tumors and play important roles in cancer. This study explored the molecular mechanism of Linc00662 in hypopharyngeal squamous cell carcinoma (HSCC). Methods: Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect gene expression in HSCC tissues. The viability and proliferation of tumor cells were measured using CCK-8 assays. HSCC cell apoptosis was measured using flow cytometry and western blotting. Cell stemness was examined using the sphere formation assay. A xenograft tumor model was established to investigate the role of Linc00662 in vivo. Results: The expression level of Linc00662 in HSCC tissues was significantly higher than that in adjacent normal tissues. The expression of Linc00662 had no significant relationship with the tumor stage. Patients with high Linc00662 expression were found to have shorter overall survival than those with low Linc00662 expression. Linc00662 over-expression promoted cell viability and inhibited apoptosis. Using online databases and a dual luciferase reporter, miR-15b-5p was confirmed as a potential downstream sponge of Linc00662. Moreover, Linc00662 was negatively associated with miR-15b-5p in HSCC cells. Depletion of miR-15b-5p can reverse the function of Linc00662 in vivo and in vitro. Furthermore, Linc00662 promotes tumor growth, which was abolished by miR-15b-5p mimics. Importantly, the stemness of cancer stem cells was mediated by the Linc00662/miR-15b-5p axis. Conclusion: Patients with HSCC with high Linc00662 showed poor prognosis and high Linc00662 induced stemness of tumor cells by targeting miR-15b-5p. Linc00662 may serve as a novel diagnostic and target marker for head and neck squamous cell carcinoma.

Myosin phosphatase targeting subunit1 controls localization and motility of Rab7-containing vesicles: Is myosin phosphatase a cytoplasmic dynein regulator?

Myosin phosphatase targeting subunit1 (MYPT1) is a critical subunit of myosin phosphatase (MP), which brings PP1Cδ phosphatase and its substrate together. We previously showed that MYPT1 depletion resulted in oblique chromatid segregation. Therefore, we hypothesized that MYPT1 may control microtubule-dependent motor activity. Dynein, a minus-end microtubule motor, is known to be involved in mitotic spindle assembly. We thus examined whether MYPT1 and dynein may interact. Proximity ligation assay and co-immunoprecipitation revealed that MYPT1 and dynein intermediate chain (DIC) were associated. We found that DIC phosphorylation is increased in MYPT1-depleted cells in vivo, and that MP was able to dephosphorylate DIC in vitro. MYPT1 depletion also altered the localization and motility of Rab7-containing vesicles. MYPT1-depletion dispersed the perinuclear Rab7 localization to the peripheral in interphase cells. The dispersed Rab7 localization was rescued by microinjection of a constitutively active, truncated MYPT1 mutant, supporting that MP is responsible for the altered Rab7 localization. Analyses of Rab7 vesicle trafficking also revealed that minus-end transport was reduced in MYPT1-depleted cells. These results suggest an unexpected role of MP: MP controls dynein activity in both mitotic and interphase cells, possibly by dephosphorylating dynein subunits including DIC.

PAX8-AS1/microRNA-25-3p/LATS2 regulates malignant progression of ovarian cancer via Hippo signaling

BACKGROUND

Ovarian cancer (OC) is a frequent malignancy of the female reproductive system. Recently, the aberrant expression of numerous lncRNAs has been confirmed as a key factor for cancer development. The regulatory role of PAX8-AS1 in some cancers has been investigated, but its role in OC progression remains unclear. This study focuses on the role and molecular mechanism of PAX8-AS1 in the malignant progression of OC.

METHODS

Bioinformatics means were adopted to analyze the expression of PAX8-AS1, microRNA-25-3p, and LATS2 in OC tissues and the binding sites between the three. qRT-PCR was employed to determine the expression of these genes in OC cells. CCK-8, colony formation, scratch healing, and Transwell assays were used to see cell viability, proliferation, migration, and invasion, respectively. Fluorescence in situ Hybridization was performed to probe the subcellular localization of PAX8-AS1. Western blot was applied to evaluate the expression and phosphorylation levels of YAP and TAZ, and an immunofluorescence assay was used to detect the translocation of them. Dual luciferase assay was applied to validate the binding relationship between PAX8-AS1 and microRNA-25-3p, as well as between microRNA-25-3p and LATS2.

RESULTS

PAX8-AS1 and LATS2 were lowly expressed. MicroRNA-25-3p was highly expressed in OC. PAX8-AS1 was expressed in cytoplasm and regulated LATS2 expression by sponging microRNA-25-3p. Overexpressing PAX8-AS1 can suppress the malignant behaviors of OC cells, whereas treatment with microRNA-mimic can reverse these results. In addition, the phosphorylation levels of YAP and TAZ increased upon oe-LATS2 treatment, and oe-LATS2 could promote YAP and TAZ translocate from the nucleus to cytoplasm. Rescue experiments demonstrated that sh-PAX8-AS1 fostered malignant progression of OC, which was reversed by simultaneous oe-LATS2.

CONCLUSION

In summary, PAX8-AS1/microRNA-25-3p/LATS2 regulated the malignant progression of OC through Hippo signaling, which suggested that PAX8-AS1/microRNA-25-3p/LATS2 axis may be a novel target for OC treatment.

A miRNA-7704/IL2RB/AKT feedback loop regulates tumorigenesis and chemoresistance in ovarian cancer

Ovarian cancer is one of the most common gynecological tumors worldwide. Despite the availability of multiple treatments for ovarian cancer, its resistance to chemotherapy remains a significant challenge. miRNAs play crucial roles in the initiation and progression of cancer by affecting processes such as differentiation, proliferation, and chemoresistance. According to microarray and qPCR analyses, miR-7704 is significantly downregulated in cisplatin-resistant cells compared to parental cells. In this study, we found that miR-7704 inhibited the proliferation and promoted cisplatin sensitivity of ovarian cancer cells in vitro and in vivo. Moreover, ectopic expression of miR-7704 had the same effect as IL2RB knockdown. Further mechanistic studies revealed that miR-7704 played an inhibitory role by regulating IL2RB expression to inactivate the AKT signaling pathway. Furthermore, IL2RB reversed the miR-7704 mediated resistance to cisplatin in ovarian cancer. Based on these findings, miR-7704 and IL2RB show the potential as novel therapeutic targets for ovarian cancer.

GALNT2 targeted by miR-139-5p promotes proliferation of clear cell renal cell carcinoma via inhibition of LATS2 activation

Polypeptide N-Acetylgalactosaminyltransferase (GALNTs) are critical enzymes that initiate mucin type-O glycosylation, and are closely associated with the occurrence and development of multiple cancers. However, the significance of GALNT2 in clear cell renal cell carcinoma (ccRCC) progression remains largely undetermined. Based on public multi-omics analysis, GALNT2 was strongly elevated in ccRCC versus adjoining nontumor tissues, and it displayed a relationship with poor overall survival (OS) of ccRCC patients. In addition, GALNT2 over-expression accelerated proliferation of renal cancer cell (RCC) lines. In contrast, GALNT2 knockdown using shRNAs suppressed cell proliferation, and this was rescued by LATS2 knockdown. Similarly, GALNT2 deficiency enhanced p-LATS2/LATS2 expression. LATS2 is activated by phosphorylation (p-LATS2) and, in turn, phosphorylate the downstream substrate protein YAP. Phosphorylated YAP (p-YAP) stimulated its degradation and cytoplasmic retention, as it was unable to translocate to the nucleus. This resulted in reduced cell proliferation. Subsequently, we explored the upstream miRNAs of GALNT2. Using dual luciferase reporter assay, we revealed that miR-139-5p interacted with the 3' UTR of GALNT2. Low miR-139-5p expression was associated with worse ccRCC patient outcome. Based on our experiments, miR-139-5p overexpression inhibited RCC proliferation, and this phenotype was rescued by GALNT2 overexpression. Given these evidences, the miR-139-5p-GALNT2-LATS2 axis is critical for RCC proliferation, and it is an excellent candidate for a new therapeutic target in ccRCC.

HIPK3 maintains sensitivity to platinum drugs and prevents disease progression in gastric cancer

In the realm of cancer therapeutics and resistance, kinases play a crucial role, particularly in gastric cancer (GC). Our study focused on platinum-based chemotherapy resistance in GC, revealing a significant reduction in homeodomain-interacting protein kinase 3 (HIPK3) expression in platinum-resistant tumors through meticulous analysis of transcriptome datasets. In vitro and in vivo experiments demonstrated that HIPK3 knockdown enhanced tumor proliferation and metastasis, while upregulation had the opposite effect. We identified the myocyte enhancer factor 2C (MEF2C) as a transcriptional regulator of HIPK3 and uncovered HIPK3's role in downregulating the morphogenesis regulator microtubule-associated protein (MAP7) through ubiquitination. Phosphoproteome profiling revealed HIPK3's inhibitory effects on mTOR and Wnt pathways crucial in cell proliferation and movement. A combined treatment strategy involving oxaliplatin, rapamycin, and IWR1-1-endo effectively overcame platinum resistance induced by reduced HIPK3 expression. Monitoring HIPK3 levels could serve as a GC malignancy and platinum resistance indicator, with our proposed treatment strategy offering novel avenues for reversing resistance in gastric cancer.

Essential role of PLD2 in hypoxia-induced stemness and therapy resistance in ovarian tumors

BACKGROUND

Hypoxia in solid tumors is an important source of chemoresistance that can determine poor patient prognosis. Such chemoresistance relies on the presence of cancer stem cells (CSCs), and hypoxia promotes their generation through transcriptional activation by HIF transcription factors.

METHODS

We used ovarian cancer (OC) cell lines, xenograft models, OC patient samples, transcriptional databases, induced pluripotent stem cells (iPSCs) and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq).

RESULTS

Here, we show that hypoxia induces CSC formation and chemoresistance in ovarian cancer through transcriptional activation of the PLD2 gene. Mechanistically, HIF-1α activates PLD2 transcription through hypoxia response elements, and both hypoxia and PLD2 overexpression lead to increased accessibility around stemness genes, detected by ATAC-seq, at sites bound by AP-1 transcription factors. This in turn provokes a rewiring of stemness genes, including the overexpression of SOX2, SOX9 or NOTCH1. PLD2 overexpression also leads to decreased patient survival, enhanced tumor growth and CSC formation, and increased iPSCs reprograming, confirming its role in dedifferentiation to a stem-like phenotype. Importantly, hypoxia-induced stemness is dependent on PLD2 expression, demonstrating that PLD2 is a major determinant of de-differentiation of ovarian cancer cells to stem-like cells in hypoxic conditions. Finally, we demonstrate that high PLD2 expression increases chemoresistance to cisplatin and carboplatin treatments, both in vitro and in vivo, while its pharmacological inhibition restores sensitivity.

CONCLUSIONS

Altogether, our work highlights the importance of the HIF-1α-PLD2 axis for CSC generation and chemoresistance in OC and proposes an alternative treatment for patients with high PLD2 expression.

NRP1 Induces Enhanced Stemness and Chemoresistance in Glioma Cells via YAP

Neuropilin-1 (NRP1), a transmembrane glycoprotein, plays an important role in the malignant progression of gliomas; however, its role in chemoresistance is not fully understood. In this study, we observed the effects of NRP1 on the stemness and chemoresistance of glioma cells and the mediating role of Yes-associated protein (YAP). We constructed NRP1 overexpressing LN-229 glioma cells. Cells were treated with recombinant NRP1 protein (rNRP1) and the YAP inhibitor Super-TDU when necessary. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect the sensitivity of cells to temozolomide (TMZ). Sphere and clone formation assays were performed to detect the sphere- and clone-forming abilities of cells. Western blotting was performed to detect cellular CD133, CD44, p-LATS1, and p-YAP protein expression. Immunofluorescence and flow cytometry were used to detect the subcellular localization of YAP and apoptosis, respectively. We found that both NRP1 overexpression and rNRP1 treatment enhanced self-renewal, TMZ resistance, and CD133 and CD44 protein expression in LN-229 cells. NRP1 overexpression and rNRP1 treatment also induced LATS1 and YAP dephosphorylation and YAP nuclear translocation. Super-TDU inhibits NRP1 overexpression-induced enhanced self-renewal and TMZ resistance in LN-229 cells. Our study suggests that NRP1 induces increased stemness in glioma cells, resulting in chemoresistance, and that this effect is associated with YAP activation.

Regulation of Hippo-YAP/CTGF signaling by combining an HDAC inhibitor and 5-fluorouracil in gastric cancer cells

Histone deacetylase (HDAC) inhibitors diminish carcinogenesis, metastasis, and cancer cell proliferation by inducing death in cancer cells. Tissue regeneration and organ development are highly dependent on the Hippo signaling pathway. Targeting the dysregulated hippo pathway is an excellent approach for cancer treatment. According to the results of this study, the combination of panobinostat, a histone deacetylase inhibitor, and 5-fluorouracil (5-FU), a chemotherapy drug, can act synergistically to induce apoptosis in gastric cancer cells. The combination of panobinostat and 5-FU was more effective in inhibiting cell viability than either treatment alone by elevating the protein levels of cleaved PARP and cleaved caspase-9. By specifically targeting E-cadherin, vimentin, and MMP-9, the combination of panobinostat and 5-FU significantly inhibited cell migration. Additionally, panobinostat significantly increased the anticancer effects of 5-FU by activating Hippo signaling (Mst 1 and 2, Sav1, and Mob1) and inhibiting the Akt signaling pathway. As a consequence, there was a decrease in the amount of Yap protein. The combination therapy of panobinostat with 5-FU dramatically slowed the spread of gastric cancer in a xenograft animal model by deactivating the Akt pathway and supporting the Hippo pathway. Since combination treatment exhibits much higher anti-tumor potential than 5-FU alone, panobinostat effectively potentiates the anti-tumor efficacy of 5-FU. As a result, it is believed that panobinostat and 5-FU combination therapy will be useful as supplemental chemotherapy in the future.

Prediction of Chemoresistance-How Preclinical Data Could Help to Modify Therapeutic Strategy in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is one of the most lethal tumors generally and the most fatal cancer of the female genital tract. The approved standard therapy consists of surgical cytoreduction and platinum/taxane-based chemotherapy, and of targeted therapy in selected patients. The main therapeutic problem is chemoresistance of recurrent and metastatic HGSOC tumors which results in low survival in the group of FIGO III/IV. Therefore, the prediction and monitoring of chemoresistance seems to be of utmost importance for the improvement of HGSOC management. This type of cancer has genetic heterogeneity with several subtypes being characterized by diverse gene signatures and disturbed peculiar epigenetic regulation. HGSOC develops and metastasizes preferentially in the specific intraperitoneal environment composed mainly of fibroblasts, adipocytes, and immune cells. Different HGSOC subtypes could be sensitive to distinct sets of drugs. Moreover, primary, metastatic, and recurrent tumors are characterized by an individual biology, and thus diverse drug responsibility. Without a precise identification of the tumor and its microenvironment, effective treatment seems to be elusive. This paper reviews tumor-derived genomic, mutational, cellular, and epigenetic biomarkers of HGSOC drug resistance, as well as tumor microenvironment-derived biomarkers of chemoresistance, and discusses their possible use in the novel complex approach to ovarian cancer therapy and monitoring.

YY1 modulates the radiosensitivity of esophageal squamous cell carcinoma through KIF3B-mediated Hippo signaling pathway

Radiotherapy is an important strategy in the comprehensive treatment of esophageal squamous cell carcinoma (ESCC). However, effectiveness of radiotherapy is still restricted by radioresistance. Herein, we aimed to understand the mechanisms underlying ESCC radioresistance, for which we looked into the potential role of YY1. YY1 was upregulated in radioresistant tissues and correlated with poor prognosis of patients with ESCC. YY1 depletion enhanced the radiosensitivity of ESCC in vitro and in vivo. Multi-group sequencing showed that downregulation of YY1 inhibited the transcriptional activity of Kinesin Family Member 3B (KIF3B), which further activated the Hippo signaling pathway by interacting with Integrin-beta1 (ITGB1). Once the Hippo pathway was activated, its main effector, Yes-associated protein 1 (YAP1), was phosphorylated in the cytoplasm and its expression reduced in the nucleus, thus enhancing the radiosensitivity by regulating its targeted genes. Our study provides new insights into the mechanisms underlying ESCC radioresistance and highlights the potential role of YY1 as a therapeutic target for ESCC.

The deubiquitinating enzyme USP19 facilitates hepatocellular carcinoma progression through stabilizing YAP

Hippo pathway plays a crucial role in the progression of hepatocellular carcinoma (HCC), and yes-associated protein (YAP) is one of the major factors of the Hippo pathway. However, the mechanism of abnormal YAP activation in HCC has not been well elucidated. Here, we screened a Deubiquitinating enzymes' (DUB) siRNA library targeting DUBs, and identified Ubiquitin Specific Peptidase 19 (USP19) as a specific deubiquitinating enzyme of YAP in HCC, which could stabilize YAP at K76 and K90 sites via removing the K48- and K11-linked ubiquitin chains. USP19 knockdown decreased the expression of YAP protein and its target gene (CTGF, CYR61, ANKRD1) expression. Through substantial in vivo and in vitro experiments, we prove that USP19 facilities the proliferation and migration of HCC. More importantly, we found that USP19 was upregulated in HCC tissues and associated with poor prognosis. In general, our research revealed a novel post-translational mechanism between USP19 and YAP in HCC, suggesting that USP19 may be a pivotal therapeutic target for HCC treatment.

A nanocomposite competent to overcome cascade drug resistance in ovarian cancer via mitochondria dysfunction and NO gas synergistic therapy

Ovarian cancer (OC) is one of the most common and recurring malignancies in gynecology. Patients with relapsed OC always develop "cascade drug resistance" (CDR) under repeated chemotherapy, leading to subsequent failure of chemotherapy. To overcome this challenge, amphiphiles (P1) carrying a nitric oxide (NO) donor (Isosorbide 5-mononitrate, ISMN) and high-density disulfide are synthesized for encapsulating mitochondria-targeted tetravalent platinum prodrug (TPt) to construct a nanocomposite (INP@TPt). Mechanism studies indicated that INP@TPt significantly inhibited drug-resistant cells by increasing cellular uptake and mitochondrial accumulation of platinum, depleting glutathione, and preventing apoptosis escape through generating highly toxic peroxynitrite anion (ONOO-). To better replicate the microenvironmental and histological characteristics of the drug resistant primary tumor, an OC patient-derived tumor xenograft (PDXOC) model in BALB/c nude mice was established. INP@TPt showed the best therapeutic effects in the PDXOC model. The corresponding tumor tissues contained high ONOO- levels, which were attributed to the simultaneous release of O2•- and NO in tumor tissues. Taken together, INP@TPt-based systematic strategy showed considerable potential and satisfactory biocompatibility in overcoming platinum CDR, providing practical applications for ovarian therapy.

The Hippo pathway in endometrial cancer: a potential therapeutic target?

Endometrial cancer, one of the most prevalent malignant cancers tumors of the female reproductive tract, has been increasing in incidence and mortality rates around the world. The Hippo pathway, one of the eight traditional human cancer signaling pathways, is an intricate signaling network that regulates cell proliferation, differentiation, and migration as well as restricting organ size in response to a range of intracellular and extracellular signals. Inhibiting the Hippo pathway results in aberrant activation of its downstream core component YAP/TAZ, which can enhance cancer cells' metabolism and maintain their stemness. Additionally, the Hippo pathway can modulate the tumor microenvironment and induce drug resistance, where tumorigenesis and tumor progression occur. However, the Hippo pathway has been little researched in endometrial cancer. Here, we aim to review how the Hippo pathway contributes to the onset, development and the potential treatment of endometrial cancer with the aim of providing new therapeutic targets.

FAT10 differentially stabilizes MYPT2 isoforms

Myosin phosphatase (MP) is an enzyme complex that regulates muscle contraction and plays important roles in various physiological and pathological conditions. Myosin phosphatase targeting subunit (MYPT) 2, a subunit of MP, interacts with protein phosphatase 1c to regulate its phosphatase activity. MYPT2 exists in various isoforms that differ in the composition of essential motifs that contribute to its function. However, regulatory mechanisms underlying these isoforms are poorly understood. Human leukocyte antigen-F adjacent transcript 10 (FAT10) is a ubiquitin-like modifier that not only targets proteins for proteasomal degradation but also stabilizes its interacting proteins. In this study, we investigated the effect of the interaction between FAT10 and MYPT2 isoform a (the canonical full-length form of MYPT2) or MYPT2 isoform f (the natural truncated form of MYPT2). FAT10 interacted with both MYPT2 isoforms a and f; however, only MYPT2 isoform f was increased by FAT10, whereas MYPT2 isoform a remained unaffected by FAT10. We further confirmed that, in contrast to MYPT2 isoform a, MYPT2 isoform f undergoes rapid degradation via the ubiquitin-proteasome pathway and that FAT10 stabilizes MYPT2 isoform f by inhibiting its ubiquitination. Therefore, our findings suggest that the interaction between FAT10 and MYPT2 isoforms leads to distinct stabilization effects on each isoform, potentially modulating MP activity.

The Interaction Between SMAD1 and YAP1 Is Correlated with Increased Resistance of Gastric Cancer Cells to Cisplatin

Drug resistance is a major obstacle leading to treating failure and poor outcome in gastric cancer (GC). This study explores the interaction between SMAD family member 1 (SMAD1) and Yes1-associated transcriptional regulator (YAP1) and their roles in cisplatin (DDP) resistance in GC. Transcriptome analysis predicted that SMAD1 is highly expressed in DDP-resistant cells. Elevated SMAD1 expression was detected in GC tissue and cells, especially in DDP-resistant cells (MKN-45/DDP and AGS/DDP). SMAD1 downregulation in cells decreased 50% inhibition value of DDP, reduced proliferation, migration, and invasion, and promoted cell cycle arrest and apoptosis. A protein-protein interaction network suggested a possible SMAD1 and YAP1 interaction in GC. The SMAD1 and YAP1 interaction was validated by chromatin immunoprecipitation (ChIP), co-immunoprecipitation (Co-IP), and luciferase assays. SMAD1 bound to YAP1 and activated its transcription. SMAD1 formed complexes with YAP1 in nucleus, and YAP1 upregulation enhanced SMAD1 activity as well. Upregulation of YAP1 restored the malignant behaviors of GC cells suppressed by SMAD1 silencing. In vivo, SMAD1 silencing suppressed growth and DDP resistance of xenograft tumors in nude mice, and this suppression was blocked by YAP1 overexpression again. In conclusion, this study demonstrates that SMAD1 can interact with YAP1 to enhance the DDP resistance of GC cells.

Targeting Hippo signaling in cancer: novel perspectives and therapeutic potential

As highly conserved among diverse species, Hippo signaling pathway regulates various biological processes, including development, cell proliferation, stem cell function, tissue regeneration, homeostasis, and organ size. Studies in the last two decades have provided a good framework for how these fundamental functions of Hippo signaling are tightly regulated by a network with numerous intracellular and extracellular factors. The Hippo signaling pathway, when dysregulated, may lead to a wide variety of diseases, especially cancer. There is growing evidence demonstrating that dysregulated Hippo signaling is closely associated with tumorigenesis, cancer cell invasion, and migration, as well as drug resistance. Therefore, the Hippo pathway is considered an appealing therapeutic target for the treatment of cancer. Promising novel agents targeting the Hippo signaling pathway for cancers have recently emerged. These novel agents have shown antitumor activity in multiple cancer models and demonstrated therapeutic potential for cancer treatment. However, the detailed molecular basis of the Hippo signaling-driven tumor biology remains undefined. Our review summarizes current advances in understanding the mechanisms by which Hippo signaling drives tumorigenesis and confers drug resistance. We also propose strategies for future preclinical and clinical development to target this pathway.

YAP1 affects the prognosis through the regulation of stemness in endometrial cancer

Background

Endometrial cancer stem-like cells (ECSCs) have been proven to be responsible for recurrence, metastasis, and drug-resistance in patients with endometrial cancer. The HIPPO pathway has been shown to play an important role in the development and maintenance of stemness in a variety of tumors. While there was less research about its function in ECSCs. The aim of this study was to explore the role of YAP1, a core molecular of HIPPO pathway, in the stemness of endometrial cancer and to reveal its influence on prognosis.

Methods

We collected specimens and clinical data from 774 patients with endometrial cancer to analyze the correlation between YAP1 expression and prognosis. We then examined the expression of YAP1 in ECSCs and EC cell lines (Ishikawa; HEC1-A) in vitro experiments. Changes in the stemness of cell lines were detected after YAP1 silencing by siRNA. Finally, high-throughput sequencing was used to predict the potential molecular interactions and mechanisms of YAP1's effect on stemness.

Result

Down-regulation of YAP1 significantly suppresses the stemness of EC cell lines. High expression of YAP1 leads to poor prognosis in EC by regulation of stemness.

Conclusion

YAP1 plays an important role in the prognosis of patients with EC by regulation of stemness.

HLF promotes ovarian cancer progression and chemoresistance via regulating Hippo signaling pathway

Hepatic leukemia factor (HLF) is aberrantly expressed in human malignancies. However, the role of HLF in the regulation of ovarian cancer (OC) remains unknown. Herein, we reported that HLF expression was upregulated in OC tissues and ovarian cancer stem cells (CSCs). Functional studies have revealed that HLF regulates OC cell stemness, proliferation, and metastasis. Mechanistically, HLF transcriptionally activated Yes-associated protein 1 (YAP1) expression and subsequently modulated the Hippo signaling pathway. Moreover, we found that miR-520e directly targeted HLF 3'-UTR in OC cells. miR-520e expression was negatively correlated with HLF and YAP1 expression in OC tissues. The combined immunohistochemical (IHC) panels exhibited a better prognostic value for OC patients than any of these components alone. Importantly, the HLF/YAP1 axis determines the response of OC cells to carboplatin treatment and HLF depletion or the YAP1 inhibitor verteporfin abrogated carboplatin resistance. Analysis of patient-derived xenografts (PDXs) further suggested that HLF might predict carboplatin benefits in OC patients. In conclusion, these findings suggest a crucial role of the miR-520e/HLF/YAP1 axis in OC progression and chemoresistance, suggesting potential therapeutic targets for OC.

Biomimetic Microenvironmental Stiffness Boosts Stemness of Pancreatic Ductal Adenocarcinoma via Augmented Autophagy

Pancreatic ductal adenocarcinoma (PDAC) features high recurrence rates and intensified lethality, accompanied by stiffening of the extracellular matrix (ECM) microenvironment, which is mainly due to the deposition, remodeling, and cross-linking of collagen. Boosted stemness plays an essential role during occurrence and progression, which indicates a poor prognosis. Therefore, it is of great importance to understand the effect of the underlying interaction of matrix stiffness and stemness on PDAC. For this purpose, a methacrylated gelatin (GelMA) hydrogel with tunable stiffness was applied for incubating MIA PaCa-2 and PANC-1 cells. The results demonstrated that compared to the soft group (5% GelMA, w/v), the expression of stemness-related genes (SOX2, OCT4, and NANOG) in the stiff group (10% GelMA, w/v) displayed pronounced elevation as well as sphere formation. Intriguingly, we also observed that matrix stiffness regulated autophagy of PDAC, which played a momentous role in stemness promotion. In order to clarify the underlying relationship between matrix stiffness-mediated cell autophagy and stemness, rescue experiments with rapamycin and chloroquine were conducted with transmission electron microscopy, immunofluorescence staining, sphere formation, and qRT-PCR assays to evaluate the level of stemness and autophagy. For exploring the molecular mechanism in depth, RNA-seq and differential expression of miRNAs were carried out, which may sensor and respond to matrix stiffness during the regulation of stemness and autophagy. In conclusion, we validated that blocking autophagy repressed the stemness induced by matrix stiffness in PDAC and provided a potential therapeutic strategy for this aggressive cancer.

DDX18 drives tumor immune escape through transcription-activated STAT1 expression in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) resists to current treatments due to its inherent tumor heterogeneity, therapy-resistant cancer stem/initiating cells survival, and immune evasion in the immunosuppressive tumor microenvironment (TME). Here, the results show that clinical PDAC and adjacent tissues undergo distinct chromatin remodeling. Multiple omics analysis revealed DEAD-box RNA helicase 18 (DDX18), a carcinogenic gene with similar H3K4me3 profile, is up-regulated and correlates with poor survival in PDAC patients. We validated that DDX18 deposits on the STAT1 promoter region and counteracts H3K27me3 deposition on the STAT1 promoter sequence by modulating the formation of the PRC2 complex to up-regulate the expression of STAT1, which results in the up-regulation of PD-L1 expression, T lymphocyte accumulation and overactivation in the highly desmoplastic and immunosuppressive pancreatic TME. DDX18-STAT1 axis inhibition also affects stemness of cancer cells, epithelial-mesenchymal transition (EMT) and disrupts the immunosuppressive TME simultaneously, producing sustained remissions of aggressive PDAC by synergizing with anti-PD-L1 therapy. Combining DDX18 inhibition with anti-PD-L1 immunochemotherapy to treat PDAC patients will pave a new way for clinical treatment of patients with PDAC. This study found that clinical PDAC and adjacent pancreatic tissues undergo distinct chromatin remodeling featured by the upregulation of DEAD-box RNA helicase 18 (DDX18). We further validated that DDX18 deposits on the STAT1 promoter region and counteracts H3K27me3 deposition on the STAT1 promoter by modulating the formation of the PRC2 complex to up-regulate the expression of STAT1. DDX18-STAT1 axis enhances the stemness of cancer cells, the upregulation of PD-L1 expression, T lymphocyte accumulation and overactivation in the highly desmoplastic and immunosuppressive pancreatic TME.

PLAGL2 promotes bladder cancer progression via RACGAP1/RhoA GTPase/YAP1 signaling

PLAGL2 is upregulated in various tumors, including bladder cancer (BCa). However, the mechanisms underlying the tumorigenic effects of PLAGL2 in BCa remain unclear. In our study, we proved that PLAGL2 was overexpressed in BCa tissues and correlated with decreased survival. Functionally, PLAGL2 deficiency significantly suppressed the proliferation and metastasis of BCa cells in vitro and in vivo. RNA sequencing, qRT‒PCR, immunoblotting, immunofluorescence staining, luciferase reporter, and ChIP assays revealed that overexpressed PLAGL2 disrupted the Hippo pathway and increased YAP1/TAZ activity by transactivating RACGAP1. Further investigations demonstrated that PLAGL2 activated YAP1/TAZ signaling via RACGAP1-mediated RhoA activation. Importantly, the RhoA inhibitor simvastatin or the YAP1/TAZ inhibitor verteporfin abrogated the proproliferative and prometastatic effects of BCa enhanced by PLAGL2. These findings suggest that PLAGL2 promotes BCa progression via RACGAP1/RhoA GTPase/YAP1 signaling. Hence, the core nodes of signaling may be promising therapeutic targets for BCa.

Deciphering Common Traits of Breast and Ovarian Cancer Stem Cells and Possible Therapeutic Approaches

Breast cancer (BC) and ovarian cancer (OC) are among the most common and deadly cancers affecting women worldwide. Both are complex diseases with marked heterogeneity. Despite the induction of screening programs that increase the frequency of earlier diagnosis of BC, at a stage when the cancer is more likely to respond to therapy, which does not exist for OC, more than 50% of both cancers are diagnosed at an advanced stage. Initial therapy can put the cancer into remission. However, recurrences occur frequently in both BC and OC, which are highly cancer-subtype dependent. Therapy resistance is mainly attributed to a rare subpopulation of cells, named cancer stem cells (CSC) or tumor-initiating cells, as they are capable of self-renewal, tumor initiation, and regrowth of tumor bulk. In this review, we will discuss the distinctive markers and signaling pathways that characterize CSC, their interactions with the tumor microenvironment, and the strategies they employ to evade immune surveillance. Our focus will be on identifying the common features of breast cancer stem cells (BCSC) and ovarian cancer stem cells (OCSC) and suggesting potential therapeutic approaches.

An immune related signature inhibits the occurrence and development of serous ovarian cancer by affecting the abundance of dendritic cells

Serous ovarian cancer is one of the major causes of cancer related death among women worldwide. The advanced diagnosis worsens the prognosis of patients with serous ovarian cancer. The immune system has an important impact on the progression of ovarian cancer. Herein, we aimed to establish an immune related prognostic signature to assist in the early diagnosis, treatment, and prognostic evaluation of patients with serous ovarian cancer. Multiple public data sets and immune related genes were obtained from various online public databases, and immune related prognostic signatures were developed through differential expression analysis, univariate Cox proportional hazard regression analysis, and the Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression model. The nomogram model, Kaplan-Meier survival curve analysis, receiver operating characteristic (ROC) curve analysis, and decision curve analysis showed that this signature had a good prediction potential. In conclusion, an immune related signature with good prediction efficiency was established through systematic bioinformatics analysis, which may play a tumor inhibition role by affecting the abundance of activated dendritic cells.

Targeting XPO6 inhibits prostate cancer progression and enhances the suppressive efficacy of docetaxel

BACKGROUND

Although XPO6, one of the Exportin family members, functions in malignant progression of certain types of cancer, its role in prostate cancer (PCa) has not been elucidated. Herein, we investigated the oncogenic effect and clarified the downstream mechanism of XPO6 in PCa cells.

METHODS

We detected the expression level of XPO6 in PCa tissues by immunohistochemistry (IHC) and analyzed the correlation between clinicopathological characteristics and XPO6 level based on TCGA database. The effects of XPO6 in the proliferation and migration or resistance to docetaxel (DTX) in PCa cells were assessed using CCK8, colony formation, wound-healing and Transwell assays. Mice experiments were performed to investigate the role of XPO6 in tumor progression and DTX effect in vivo. Further, functional analysis of DEGs revealed the correlation of XPO6 with Hippo pathway and XPO6 could promote the expression and nuclear translocation of YAP1 protein. Furthermore, blocking Hippo pathway with YAP1 inhibitor leads to the loss of XPO6-mediated regulation of biological functions.

RESULTS

XPO6 was highly expressed and positively correlated with the clinicopathological characteristics of PCa. Functional experiments indicated that XPO6 could promote tumor development and DTX resistance in PCa. Mechanistically, we further confirmed that XPO6 could regulate Hippo pathway via mediating YAP1 protein expression and nuclear translocation thereby promoting PCa progression and chemotherapeutic resistance.

CONCLUSION

In conclusion, our research reveals that XPO6 potentially function as an oncogene and promotes DTX resistance of PCa, suggesting that XPO6 could be both a potential prognostic marker as well as a therapeutic target to effectively overcome DTX resistance.

Metabolic pathways of potential miRNA biomarkers derived from liquid biopsy in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the type of OC with the highest mortality rate. Due to the asymptomatic nature of the disease and few available diagnostic tests, it is mostly diagnosed at the advanced stage. Therefore, the present study aimed to discover predictive and/or early diagnostic novel circulating microRNAs (miRNAs or miRs) for EOC. Firstly, microarray analysis of miRNA expression levels was performed on 32 samples of female individuals: Eight plasma samples from patients with pathologically confirmed EOC (mean age, 45 (30-54) years), eight plasma samples from matched healthy individuals (HIs) (mean age, 44 (30-65) years), eight EOC tissue samples (mean age, 45 (30-54) years) and eight benign ovarian (mean age, 35 (17-70) years) neoplastic tissue samples A total of 31 significantly dysregulated miRNAs in serum and three miRNAs in tissue were identified by microarray. The results were validated using reverse transcription-quantitative PCR on samples from 10 patients with pathologically confirmed EOC (mean age, 47(30-54) years), 10 matched His (mean age, 40(26-65) years], 10 EOC tissue samples (mean age, 47(30-54) years) and 10 benign ovarian neoplastic tissue samples (mean age, 40(17-70) years). The 'Kyoto Encyclopedia of Genes and Genomes' (KEGG) database was used for target gene and pathway analysis. A total of three miRNAs from EOC serum (hsa-miR-1909-5p, hsa-miR-885-5p and hsa-let-7d-3p) and one microRNA from tissue samples (hsa-miR-200c-3p) were validated as significant to distinguish patients with EOC from HIs. KEGG pathway enrichment analysis showed seven significant pathways, which included 'prion diseases', 'proteoglycans in cancer', 'oxytocin signaling pathway', 'hippo signaling pathway', 'adrenergic signaling in cardiomyocytes', 'oocyte meiosis' and 'thyroid hormone signaling pathway', in which the validated miRNAs served a role. This supports the hypothesis that four validated miRNAs, have the potential to be a biomarker of EOC diagnosis and target for treatment.

Glutamine metabolism targeting liposomes for synergistic chemosensitization and starvation therapy in ovarian cancer

Platinum-based chemotherapy is a first-line therapeutic regimen against ovarian cancer (OC); however, the therapeutic potential is always reduced by glutamine metabolism. Herein, a valid strategy of inhibiting glutamine metabolism was proposed to cause tumor starvation and chemosensitization. Specifically, reactive oxygen species-responsive liposomes were developed to co-deliver cisplatin (CDDP) and bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to CDDP by reducing glutathione generation to prevent CDDP detoxification, suppressing ATP production to avoid CDDP efflux, hindering nucleotide synthesis to aggravate DNA damage induced by CDDP, and blocking mammalian target of rapamycin (mTOR) signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs. STATEMENT OF SIGNIFICANCE: This work proposed a valid strategy of inhibiting glutamine metabolism to cause tumor starvation and chemosensitization. Specifically, ROS-responsive liposomes were developed to co-deliver cisplatin CDDP and BPTES [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to cisplatin by reducing glutathione generation to prevent cisplatin detoxification, suppressing ATP production to avoid cisplatin efflux, hindering nucleotide synthesis to aggravate DNA damage induced by cisplatin, and blocking mTOR signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs.

The lysophosphatidic acid-regulated signal transduction network in ovarian cancer cells and its role in actomyosin dynamics, cell migration and entosis

Lysophosphatidic acid (LPA) species accumulate in the ascites of ovarian high-grade serous cancer (HGSC) and are associated with short relapse-free survival. LPA is known to support metastatic spread of cancer cells by activating a multitude of signaling pathways via G-protein-coupled receptors of the LPAR family. Systematic unbiased analyses of the LPA-regulated signal transduction network in ovarian cancer cells have, however, not been reported to date. Methods: LPA-induced signaling pathways were identified by phosphoproteomics of both patient-derived and OVCAR8 cells, RNA sequencing, measurements of intracellular Ca²⁺ and cAMP as well as cell imaging. The function of LPARs and downstream signaling components in migration and entosis were analyzed by selective pharmacological inhibitors and RNA interference. Results: Phosphoproteomic analyses identified > 1100 LPA-regulated sites in > 800 proteins and revealed interconnected LPAR1, ROCK/RAC, PKC/D and ERK pathways to play a prominent role within a comprehensive signaling network. These pathways regulate essential processes, including transcriptional responses, actomyosin dynamics, cell migration and entosis. A critical component of this signaling network is MYPT1, a stimulatory subunit of protein phosphatase 1 (PP1), which in turn is a negative regulator of myosin light chain 2 (MLC2). LPA induces phosphorylation of MYPT1 through ROCK (T853) and PKC/ERK (S507), which is majorly driven by LPAR1. Inhibition of MYPT1, PKC or ERK impedes both LPA-induced cell migration and entosis, while interference with ROCK activity and MLC2 phosphorylation selectively blocks entosis, suggesting that MYPT1 figures in both ROCK/MLC2-dependent and -independent pathways. We finally show a novel pathway governed by LPAR2 and the RAC-GEF DOCK7 to be indispensable for the induction of entosis. Conclusion: We have identified a comprehensive LPA-induced signal transduction network controlling LPA-triggered cytoskeletal changes, cell migration and entosis in HGSC cells. Due to its pivotal role in this network, MYPT1 may represent a promising target for interfering with specific functions of PP1 essential for HGSC progression.

Hippo Signaling in the Ovary: Emerging Roles in Development, Fertility, and Disease

Emerging studies indicate that the Hippo pathway, a highly conserved pathway that regulates organ size control, plays an important role in governing ovarian physiology, fertility, and pathology. Specific to the ovary, the spatiotemporal expression of the major components of the Hippo signaling cascade are observed throughout the reproductive lifespan. Observations from multiple species begin to elucidate the functional diversity and molecular mechanisms of Hippo signaling in the ovary in addition to the identification of interactions with other signaling pathways and responses to various external stimuli. Hippo pathway components play important roles in follicle growth and activation, as well as steroidogenesis, by regulating several key biological processes through mechanisms of cell proliferation, migration, differentiation, and cell fate determination. Given the importance of these processes, dysregulation of the Hippo pathway contributes to loss of follicular homeostasis and reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency, and ovarian cancers. This review highlights what is currently known about the Hippo pathway core components in ovarian physiology, including ovarian development, follicle development, and oocyte maturation, while identifying areas for future research to better understand Hippo signaling as a multifunctional pathway in reproductive health and biology.

The Hippo signalling pathway and its implications in human health and diseases

As an evolutionarily conserved signalling network, the Hippo pathway plays a crucial role in the regulation of numerous biological processes. Thus, substantial efforts have been made to understand the upstream signals that influence the activity of the Hippo pathway, as well as its physiological functions, such as cell proliferation and differentiation, organ growth, embryogenesis, and tissue regeneration/wound healing. However, dysregulation of the Hippo pathway can cause a variety of diseases, including cancer, eye diseases, cardiac diseases, pulmonary diseases, renal diseases, hepatic diseases, and immune dysfunction. Therefore, therapeutic strategies that target dysregulated Hippo components might be promising approaches for the treatment of a wide spectrum of diseases. Here, we review the key components and upstream signals of the Hippo pathway, as well as the critical physiological functions controlled by the Hippo pathway. Additionally, diseases associated with alterations in the Hippo pathway and potential therapies targeting Hippo components will be discussed.

MYPT1 inhibits the metastasis of renal clear cell carcinoma via the MAPK8/N-cadherin pathway

Myosin phosphatase target subunit 1 (MYPT1) is a subunit of myosin phosphatase that is capable of regulating smooth muscle contraction. MYPT1 has been reported to be involved in a wide variety of tumours, but its expression and biological functions in renal clear cell carcinoma (ccRCC) remain obscure. Herein, we analysed the relationship between patient clinicopathological characteristics and MYPT1 expression levels in ccRCC patients using a tissue microarray (TMA) and data retrieved from the TCGA-KIRC dataset. MYPT1 was overexpressed or depleted using siRNA in ccRCC cells to assess the effects on migration and invasion in vitro and in vivo. Additionally, RNA-sequencing and bioinformatics analysis were performed to investigate the precise mechanism. MYPT1 expression in ccRCC tissues was observed to be lower than that in nonmalignant tissues (P < 0.05). In addition, MYPT1 downregulation was closely linked to advanced pathological stage (P < 0.05), and poor OS (overall survival; P < 0.05). Functionally, increased expression of MYPT1 suppressed ccRCC migration and invasion in vitro, and inhibited tumour metastasis in vivo. In addition, MYPT1 overexpression exerted its suppressive effects via the MAPK8/N-cadherin pathway in ccRCC.

Phase separation in Cancer: From the Impacts and Mechanisms to Treatment potentials

Cancer is a public health problem of great concern, and it is also one of the main causes of death in the world. Cancer is a disease characterized by dysregulation of diverse cellular processes, including avoiding growth inhibitory factors, avoiding immune damage and promoting metastasis, etc. However, the precise mechanism of tumorigenesis and tumor progression still needs to be further elucidated. Formations of liquid-liquid phase separation (LLPS) condensates are a common strategy for cells to achieve diverse functions, such as chromatin organization, signal transduction, DNA repair and transcriptional regulation, etc. The biomolecular aggregates formed by LLPS are mainly driven by multivalent weak interactions mediated by intrinsic disordered regions (IDRs) in proteins. In recent years, aberrant phase separations and transition have been reported to be related to the process of various diseases, such as neurodegenerative diseases and cancer. Herein, we discussed recent findings that phase separation regulates tumor-related signaling pathways and thus contributes to tumor progression. We also reviewed some tumor virus-associated proteins to regulate the development of virus-associated tumors via phase separation. Finally, we discussed some possible strategies for treating tumors by targeting phase separation.

Immunotherapy checkpoints in ovarian cancer vasculogenic mimicry: Tumor immune microenvironments, and drugs

Vasculogenic mimicry (VM), a vessel-like structure independent of endothelial cells, commonly exists in solid tumors which requires blood vessels to grow. As a special source of blood supply for tumor progression to a more aggressive state, VM has been observed in a variety of human malignant tumors and is tightly associated with tumor proliferation, invasion, metastasis, and poor patient prognosis. So far, various factors, including immune cells and cytokines, were reported to regulate ovarian cancer progression by influencing VM formation. Herein, we review the mechanisms that regulate VM formation in ovarian cancer and the effect of cells, cytokines, and signaling molecules in the tumor microenvironment on VM formation, Furthermore, we summarize the current clinical application of drugs targeting VM formation.

The Hippo Pathway Effector Transcriptional Co-activator With PDZ-Binding Motif Correlates With Clinical Prognosis and Immune Infiltration in Colorectal Cancer

The transcriptional co-activator with PDZ-binding motif (TAZ) is a downstream effector of the Hippo pathway. It has been identified as an oncogene in certain tumor types; however, the function and role of TAZ in colorectal cancer (CRC) has not been illustrated. Here, we aimed to analyze the expression and role of TAZ in CRC. In this study, we investigated the expression level of TAZ in 127 CRC and matched adjacent normal tissues by immunohistochemistry (IHC) and analyzed its correlation with clinicopathological characteristics in CRC. Moreover, we further analyzed the role of TAZ in the CRC-associated immunology using integrative bioinformatic analyses. The cBioPortal and WebGestalt database were used to analyze the co-expressed genes and related pathways of TAZ in CRC by gene ontology (GO) and KEGG enrichment analyses. Meanwhile, the correlations between TAZ and the infiltrating immune cells and gene markers were analyzed by TIMER database. Our study revealed that TAZ expression is higher in CRC tissues than in matched adjacent non-tumor tissues. In addition, CRC patients with higher TAZ expression demonstrated poor overall survival (OS) and recurrent-free survival rates as compared to CRC patients with lower expression of TAZ. Furthermore, the TAZ expression was identified to closely associate with the immune infiltration of CD4 + T, CD8 + T, and B cells. Taken together, our findings suggest that TAZ may serve as a promising prognostic biomarker and therapeutic target in CRC.

The Roles of Drug Metabolism-Related ADH1B in Immune Regulation and Therapeutic Response of Ovarian Cancer

Background: The different pharmacological effects of drugs in different people can be explained by the polymorphisms of drug metabolism-related genes. Emerging studies have realized the importance of drug metabolism-related genes in the treatment and prognosis of cancers, including ovarian cancer (OV). In this study, using comprehensive bioinformatics and western blot, we identified that the drug metabolism-related gene, ADH1B, was significantly down-regulated in OV cells and tissues. The patients with a high level of ADH1B presented a good prognosis. We also found a negative correlation between ADH1B expression and the activity of chemotherapeutic agents, such as cyclophosphamide. In addition, positive correlations were observed between ADH1B expression and multiple immune checkpoints, including LAG3 and HAVCR2. The immune infiltration analysis further indicated that aberrantly expressed ADH1B might have important roles in regulating the infiltration of macrophages and neutrophils in OV tissues. Then, the co-expression analysis was conducted and the top three enriched KEGG pathways were spliceosome, RNA transport, and DNA replication. In conclusion, the drug metabolism-related gene ADH1B and its interactive network play an essential role in the immune regulation and therapeutic response and maybe identified as promising therapeutic targets for OV patients.

The interplay between noncoding RNA and YAP/TAZ signaling in cancers: molecular functions and mechanisms

The Hippo signaling pathway was found coordinately modulates cell regeneration and organ size. Its dysregulation contributes to uncontrolled cell proliferation and malignant transformation. YAP/TAZ are two critical effectors of the Hippo pathway and have been demonstrated essential for the initiation or growth of most tumors. Noncoding RNAs (ncRNAs), including miRNAs, lncRNAs, and circRNAs, have been shown to play critical roles in the development of many cancers. In the past few decades, a growing number of studies have revealed that ncRNAs can directly or indirectly regulate YAP/TAZ signaling. YAP/TAZ also regulate ncRNAs expression in return. This review summarizes the interactions between YAP/TAZ signaling and noncoding RNAs together with their biological functions on cancer progression. We also try to describe the complex feedback loop existing between these components.

The biology of YAP in programmed cell death

In the last few decades, YAP has been shown to be critical in regulating tumor progression. YAP activity can be regulated by many kinase cascade pathways and proteins through phosphorylation and promotion of cytoplasmic localization. Other factors can also affect YAP activity by modulating its binding to different transcription factors (TFs). Programmed cell death (PCD) is a genetically controlled suicide process present with the scope of eliminating cells unnecessary or detrimental for the proper development of the organism. In some specific states, PCD is activated and facilitates the selective elimination of certain types of tumor cells. As a candidate oncogene correlates with many regulatory factors, YAP can inhibit or induce different forms of PCD, including apoptosis, autophagy, ferroptosis and pyroptosis. Furthermore, YAP may act as a bridge between different forms of PCD, eventually leading to different outcomes regarding tumor development. Researches on YAP and PCD may benefit the future development of novel treatment strategies for some diseases. Therefore, in this review, we provide a general overview of the cellular functions of YAP and the relationship between YAP and PCD.

MiR-320b and miR-320d as Biomarkers to Predict and Participate in the Formation of Platinum Resistance in Ovarian Cancer Patients

Patients with ovarian cancer who receive platinum-based chemotherapy typically develop platinum resistance, which leads to tumor recurrence and mortality. Therefore, finding the underlying mechanisms and biomarkers is critical. A total of 51 platinum-resistant and 70 platinum-sensitive ovarian cancer patients were enrolled in this study. We examined the GSE131978 dataset in the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus database for differentially expressed long non-coding RNAs and messenger RNAs (mRNAs) between platinum-resistant and platinum-sensitive patients and completed a microRNA chip analysis. After filtering by Pearson correlation analysis, the competitive endogenous RNA (ceRNA) networks were subsequently constructed. Then, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology enrichment analyses about mRNAs in ceRNA networks were accomplished. More crucially, we demonstrated the differentially expressed microRNAs using quantitative real-time PCR and fluorescence in situ hybridization. The feasibility of microRNAs as biomarkers to predict platinum resistance and tumor recurrence was assessed using the receiver operating characteristic curve and survival analysis. MiR-320b and miR-320d exhibited high area under the curve values of 0.757 and 0.702, respectively. In our study, ceRNA networks including miR-320b and miR-320d probably provided novel insights for platinum resistance in ovarian cancer patients.

Circ_0058063 contributes to cisplatin-resistance of bladder cancer cells by upregulating B2M through acting as RNA sponges for miR-335-5p

Bladder cancer (BC) is one of the most common malignant tumors of the urinary system, and cisplatin (CDDP) is a critical chemical drug for the treatment of BC. However, CDDP-resistance seriously limits the therapeutic efficacy of this drug for clinical utilization. Thus, identification of pivotal molecule targets that regulate CDDP-resistance in BC become urgent and necessary. In this study, we firstly identified a novel BC-associated circular RNA circ_0058063 that participates in the regulation of CDDP-resistance in BC. Specifically, circ_0058063 was significantly overexpressed in CDDP-resistant tissue and cells, in contrast with the corresponding CDDP-sensitive counterparts. Further loss-of-function experiments validated that downregulation of circ_0058063 suppressed cell proliferation and tumor growth, whereas induced cell apoptosis in the CDDP-resistant BC cells in vitro and in vivo. In addition, we disclosed that circ_0058063 acts as a sponge for miR-335-5p to positively regulate B2M expression, and further rescuing experiments verified that the enhancing effects of sh-circ_0058063 on CDDP-sensitivity in the CDDP-resistant BC cells were abrogated by silencing miR-335-5p. Taken together, our results demonstrated that circ_0058063 contributed to CDDP resistance of bladder cancer cells via sponging miR-335-5p, and B2M might be the downstream effector gene. This study firstly evidenced that targeting circ_0058063 might be an effective strategy to improve CDDP-sensitivity in BC.

CCNB1, Negatively Regulated by miR-559, Promotes the Proliferation, Migration, and Invasion of Ovarian Carcinoma Cells

Cyclin B1 (CCNB1) is regarded as an oncogene in multiple tumors. This work aims to investigate the expression, function, and related mechanisms of CCNB1 in ovarian carcinoma (OC). Three microarray datasets (GSE14407, GSE18520, and GSE54388) were obtained from the Gene Expression Omnibus (GEO) database and screened for differentially expressed genes (DEGs) of OC tissues and normal ovarian tissues. CCNB1 expression in OC tissues and paracancerous tissues was detected by immunohistochemistry. Kaplan-Meier plotter database was utilized to analyze the correlation between CCNB1 expression and the prognosis of OC patients. After the loss-of-function and gain-of-function cell models were established, cell counting kit-8 (CCK-8), bromo-deoxyuridine (BrdU), and transwell experiments were employed to examine the proliferation, migration, and invasion of OC cells, respectively. The targeting relationship between miR-559 and CCNB1 was verified using the dual-luciferase reporter gene experiment. The expressions of CCNB1 mRNA and miR-559 were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Western blot was used to quantify the protein expression of CCNB1. In addition, xenograft nude mouse models were established to examine the effects of CCNB1 on lung metastasis in vivo. CCNB1 expression was markedly increased in OC tissues and cell lines. The overall survival, progression-free survival, and post-progression survival of OC patients with high CCNB1 expression were significantly shorter. OC cell proliferation, migration, and invasion were enhanced by CCNB1 overexpression while CCNB1 knockdown led to opposite effects. MiR-559 expression was remarkably reduced in OC tissues and cell lines, and miR-559 markedly suppressed the malignant characteristics of OC cells. Besides, miR-559 directly targeted the 3' UTR of CCNB1 mRNA and reduced CCNB1 expression at both the mRNA and protein levels. Overexpression of CCNB1 accelerated lung metastasis of OC cells in vivo. CCNB1, of which expression is modulated by miR-559, facilitates proliferation, migration, and invasion of OC cells, therefore, working as a potential therapeutic target of OC. This work provides new insights into the clinical diagnosis and treatment of OC.

Molecular mechanisms of platinum‑based chemotherapy resistance in ovarian cancer (Review)

Cisplatin is one of the most effective chemotherapy drugs for ovarian cancer, but resistance is common. The initial response to platinum‑based chemotherapy is as high as 80%, but in most advanced patients, final relapse and death are caused by acquired drug resistance. The development of resistance to therapy in ovarian cancer is a significant hindrance to therapeutic efficacy. The resistance of ovarian cancer cells to chemotherapeutic mechanisms is rather complex and includes multidrug resistance, DNA damage repair, cell metabolism, oxidative stress, cell cycle regulation, cancer stem cells, immunity, apoptotic pathways, autophagy and abnormal signaling pathways. The present review provided an update of recent developments in our understanding of the mechanisms of ovarian cancer platinum‑based chemotherapy resistance, discussed current and emerging approaches for targeting these patients and presented challenges associated with these approaches, with a focus on development and overcoming resistance.