RhoC regulates radioresistance via crosstalk of ROCK2 with the DNA repair machinery in cervical cancer

The Distant Molecular Effects on the Brain by Cancer Treatment

Cancer survivors experience cancer-related cognitive impairment (CRCI) secondary to treatment. Chemotherapy and radiation therapy independently contribute to cognitive dysfunction; however, the underlying mechanisms leading to dysfunction remain unclear. We characterized brain gene expression changes in a mouse model of CRCI to identify the mechanistic underpinnings. Eleven-to-twelve-week-old SKH1 mice were treated with doxorubicin (DOX), hindlimb radiation (RT), concurrent hindlimb radiation and doxorubicin (DOX-RT), or no treatment (control). Sixteen days following treatment, gene expression was measured from murine brains using the NanoString nCounter® glial profiling panel. Gene expression was normalized and compared between groups. No two groups shared the same expression pattern, and only Gnb1 and Srpr were upregulated in multiple treatment groups. Brains from DOX-treated mice had upregulated Atf2, Atp5b, Gnb1, Rad23b, and Srpr and downregulated Sirt5 expression compared to control brains. Brains from RT-treated mice demonstrated increased Abcg2 and Fgf2 and decreased C1qa and C1qb expression compared to control brains. Brains from DOX-RT-treated mice had upregulated Adar, E2f3, Erlec1, Gnb1, Srpr, Vim, and Pdgfra expression and downregulated Rock2 and Inpp5f expression compared to control brains. The gene expression changes demonstrated here highlight roles for neuronal transmission and oxidative stress in the pathogenesis of doxorubicin-related CRCI and inflammation in RT-related CRCI.

Review of possible mechanisms of radiotherapy resistance in cervical cancer

Radiotherapy is one of the main treatments for cervical cancer. Early cervical cancer is usually considered postoperative radiotherapy alone. Radiotherapy combined with cisplatin is the standard treatment for locally advanced cervical cancer (LACC), but sometimes the disease will relapse within a short time after the end of treatment. Tumor recurrence is usually related to the inherent radiation resistance of the tumor, mainly involving cell proliferation, apoptosis, DNA repair, tumor microenvironment, tumor metabolism, and stem cells. In the past few decades, the mechanism of radiotherapy resistance of cervical cancer has been extensively studied, but due to its complex process, the specific mechanism of radiotherapy resistance of cervical cancer is still not fully understood. In this review, we discuss the current status of radiotherapy resistance in cervical cancer and the possible mechanisms of radiotherapy resistance, and provide favorable therapeutic targets for improving radiotherapy sensitivity. In conclusion, this article describes the importance of understanding the pathway and target of radioresistance for cervical cancer to promote the development of effective radiotherapy sensitizers.

PSME3 induces radioresistance and enhances aerobic glycolysis in cervical cancer by regulating PARP1

Cervical cancer (CC) ranks the fourth in gynecologic cancers. The incidence and mortality of CC has been decreased due to the cancer screening and early treatments in recent years, but the prognosis of CC patients at advanced stage is still sorrowful. Whether PSME3 exerted a role in the radioresistance of CC cells remains to be investigated. In this study, the expression of PSME3 in mRNA and protein levels was measured by RT-qPCR and western blot analysis, and increased expression of PSME3 in CC tissues and cells was observed. CCK-8 and colony formation assay revealed that the cell viability and proliferation of Hela and CaSki cells treated with different doses of X-ray was reduced due to the depletion of PSME3, indicating that silencing of PSME3 enhanced the radiosensitivity of CC cells. In addition, repair on DNA damage in CC cells was enhanced by PSME3 and the damage was attenuated by PSME3. Besides, the expression of glycolysis-related proteins (GLUT1, PGC-1α, LDHA and HK2) were enhanced by PSME3 but reduced by silencing PSME3 in CC cells. PSME3 restraint attenuated the levels of glucose consumption and lactate production, suggesting PSME3 depletion suppressed abnormal glycolysis of CC cells. Mechanically, PSME3 increased the PARP1 expression via elevating c-myc. Finally, we observed PSME3 attenuation inhibited CC growth in vivo. In conclusion, PSME3 enhanced radioresistance and aerobic glycolysis in CC by regulating PARP1, which might shed a light into the function of PSME3 in CC treatment.

A landscape of response to drug combinations in non-small cell lung cancer

Combination of anti-cancer drugs is broadly seen as way to overcome the often-limited efficacy of single agents. The design and testing of combinations are however very challenging. Here we present a uniquely large dataset screening over 5000 targeted agent combinations across 81 non-small cell lung cancer cell lines. Our analysis reveals a profound heterogeneity of response across the tumor models. Notably, combinations very rarely result in a strong gain in efficacy over the range of response observable with single agents. Importantly, gain of activity over single agents is more often seen when co-targeting functionally proximal genes, offering a strategy for designing more efficient combinations. Because combinatorial effect is strongly context specific, tumor specificity should be achievable. The resource provided, together with an additional validation screen sheds light on major challenges and opportunities in building efficacious combinations against cancer and provides an opportunity for training computational models for synergy prediction.

Combined GSK-3β and MEK inhibitors modulate the stemness and radiotherapy sensitivity of cervical cancer stem cells through the Wnt signaling pathway

Cancer stem cells (CSCs) are the basis of cancer and lead to the recurrence and metastasis of cervical cancer. The aim of this study was to investigate the effects of antineoplastic agents on the stemness and radiotherapy sensitivity of cervical CSCs. Side population (SP) and non-side population (NSP) cells from the SiHa cervical cancer cell line were separated using flow cytometry. The cell spheroidization, proliferation, and subcutaneous tumor formation abilities of SP cells were stronger than those of NSP cells, and cervical CSC marker expressions increased in SP cells. The proliferation, anti-apoptosis and migration of SP cells under ionizing radiation were higher than those of SiHa cells. GSK-3β and/or MEK inhibitors can increase the proliferation, migration and anti-apoptosis of SP cells, and CSC marker expressions. The Wnt pathway inhibitor decreased CSC stemness maintenance by combination of GSK-3β and MEK inhibitors. Injection of GSK-3β and MEK inhibitors under ionizing radiation promoted tumor growth and activated downstream factor expressions in the Wnt signaling pathway in vivo. This study demonstrated that combining GSK-3β and MEK inhibitors can activate Wnt signaling pathway in cervical CSCs, thereby affecting their stemness maintenance and radiotherapy sensitivity.

RhoC in association with TET2/WDR5 regulates cancer stem cells by epigenetically modifying the expression of pluripotency genes

Emerging evidence illustrates that RhoC has divergent roles in cervical cancer progression where it controls epithelial to mesenchymal transition (EMT), migration, angiogenesis, invasion, tumor growth, and radiation response. Cancer stem cells (CSCs) are the primary cause of recurrence and metastasis and exhibit all of the above phenotypes. It, therefore, becomes imperative to understand if RhoC regulates CSCs in cervical cancer. In this study, cell lines and clinical specimen-based findings demonstrate that RhoC regulates tumor phenotypes such as clonogenicity and anoikis resistance. Accordingly, inhibition of RhoC abrogated these phenotypes. RNA-seq analysis revealed that RhoC over-expression resulted in up-regulation of 27% of the transcriptome. Further, the Infinium MethylationEPIC array showed that RhoC over-expressing cells had a demethylated genome. Studies divulged that RhoC via TET2 signaling regulated the demethylation of the genome. Further investigations comprising ChIP-seq, reporter assays, and mass spectrometry revealed that RhoC associates with WDR5 in the nucleus and regulates the expression of pluripotency genes such as Nanog. Interestingly, clinical specimen-based investigations revealed the existence of a subset of tumor cells marked by RhoC+/Nanog+ expression. Finally, combinatorial inhibition (in vitro) of RhoC and its partners (WDR5 and TET2) resulted in increased sensitization of clinical specimen-derived cells to radiation. These findings collectively reveal a novel role for nuclear RhoC in the epigenetic regulation of Nanog and identify RhoC as a regulator of CSCs. The study nominates RhoC and associated signaling pathways as therapeutic targets.

Cervical cancer heterogeneity: a constant battle against viruses and drugs

Cervical cancer is the first identified human papillomavirus (HPV) associated cancer and the most promising malignancy to be eliminated. However, the ever-changing virus subtypes and acquired multiple drug resistance continue to induce failure of tumor prevention and treatment. The exploration of cervical cancer heterogeneity is the crucial way to achieve effective prevention and precise treatment. Tumor heterogeneity exists in various aspects including the immune clearance of viruses, tumorigenesis, neoplasm recurrence, metastasis and drug resistance. Tumor development and drug resistance are often driven by potential gene amplification and deletion, not only somatic genomic alterations, but also copy number amplifications, histone modification and DNA methylation. Genomic rearrangements may occur by selection effects from chemotherapy or radiotherapy which exhibits genetic intra-tumor heterogeneity in advanced cervical cancers. The combined application of cervical cancer therapeutic vaccine and immune checkpoint inhibitors has become an effective strategy to address the heterogeneity of treatment. In this review, we will integrate classic and recently updated epidemiological data on vaccination rates, screening rates, incidence and mortality of cervical cancer patients worldwide aiming to understand the current situation of disease prevention and control and identify the direction of urgent efforts. Additionally, we will focus on the tumor environment to summarize the conditions of immune clearance and gene integration after different HPV infections and to explore the genomic factors of tumor heterogeneity. Finally, we will make a thorough inquiry into completed and ongoing phase III clinical trials in cervical cancer and summarize molecular mechanisms of drug resistance among chemotherapy, radiotherapy, biotherapy, and immunotherapy.

LACTB suppresses migration and invasion of glioblastoma via downregulating RHOC/Cofilin signaling pathway

Glioblastoma (GBM) is the most malignant tumor in human brain. High invasiveness of this tumor is the main reason causing treatment failure and recurrence. Previous study has found that LACTB is a novel tumor suppressor in breast cancer. Moreover, the function of LACTB in other tumors and mechanisms involving LACTB were also reported. However, the role and relevant mechanisms of LACTB in GBM invasion remains to be revealed. Our aim is to investigate the role LACTB in GBM migration and invasion. We found that LACTB was downregulated in gliomas compared to normal brain tissues. Overexpression of LACTB suppressed migration and invasion of LN229 and U87 cell lines. Mechanistically, LACTB overexpression downregulated the mesenchymal markers. Moreover, LACTB overexpression downregulated the expression of RHOC and inhibited RHOC/Cofilin signaling pathway. The study suggests that LACTB suppresses migration and invasion of GBM cell lines via downregulating RHOC/Cofilin signaling pathway. These findings suggest that LACTB may be a potential treatment target of GBM.

Recent progress of the tumor microenvironmental metabolism in cervical cancer radioresistance

Radiotherapy is widely used as an indispensable treatment option for cervical cancer patients. However, radioresistance always occurs and has become a big obstacle to treatment efficacy. The reason for radioresistance is mainly attributed to the high repair ability of tumor cells that overcome the DNA damage caused by radiotherapy, and the increased self-healing ability of cancer stem cells (CSCs). Accumulating findings have demonstrated that the tumor microenvironment (TME) is closely related to cervical cancer radioresistance in many aspects, especially in the metabolic processes. In this review, we discuss radiotherapy in cervical cancer radioresistance, and focus on recent research progress of the TME metabolism that affects radioresistance in cervical cancer. Understanding the mechanism of metabolism in cervical cancer radioresistance may help identify useful therapeutic targets for developing novel therapy, overcome radioresistance and improve the efficacy of radiotherapy in clinics and quality of life of patients.

Acquired temozolomide resistance in MGMTlow gliomas is associated with regulation of homologous recombination repair by ROCK2

It was reported that MGMT^low gliomas may still be resistant to TMZ, while the mechanisms remain poorly understood. In this study, we demonstrated that rho-associated kinase 2 (ROCK2), a cytoskeleton regulator, was highly expressed in MGMT^low recurrent gliomas, and its expression strongly correlated with poor overall survival (OS) time in a subset of MGMT^low recurrent gliomas patients with TMZ therapy. And we also found that overactive ROCK2 enhanced homologous recombination repair (HR) in TMZ-resistant (TMZ-R) glioma cell lines with low MGMT expression. Silencing ROCK2 impaired HR repair, and induced double-strand break (DSB) and eradicated TMZ-R glioma cells in culture. Notably, in MGMT^low TMZ-R models, as a key factor of HR, ataxia telangiectasia-mutated (ATM) expression was upregulated directly by hyper-activation of ROCK2 to improve HR efficiency. ROCK2 enhanced the binding of transcription factor zinc finger E-box binding homeobox 1 (ZEB1) to ATM promoter for increasing ATM expression. Moreover, ROCK2 transformed ZEB1 into a gene activator via Yes-associated protein 1 (YAP1). These results provide evidence for the use of ROCK inhibitors in the clinical therapy for MGMT^low TMZ-resistant glioma. Our study also offered novel insights for improving therapeutic management of MGMT^low gliomas.

ROCK2 Polymorphism and Expression Contribute to Increased Susceptibility and Poor Prognosis in Hepatocellular Carcinoma

Aim

To analyze the association between ROCK2 gene polymorphism/expression and susceptibility/prognosis of hepatocellular carcinoma (HCC).

Methods

Peripheral venous blood from 204 hepatocellular carcinoma patients (HCC group), 242 chronic hepatitis B patients (CHB group), 215 liver cirrhosis patients (LC group) and 201 healthy volunteers (normal group) were collected. ROCK2 gene (including the rs9808232 locus) was amplified by PCR and the products were sequenced. Tumor tissues from patients with HCC and liver tissues from CHB, LC and normal groups were collected, and mRNA and protein expression of ROCK2 gene in liver tissues were tested by RT-qPCR and immunofluorescence, respectively.

Results

Compared with the normal group, the mRNA and protein expression levels of ROCK2 in the HCC group increased significantly (P < 0.05), but there are no obvious increases in the CHB and LC groups (P > 0.05). ROCK2 gene rs9808232 polymorphism was associated with an increased susceptibility of HCC, and genotypes AC and CC may be risk factors for HCC (P < 0.001). There was a significant association between the ROCK2 gene rs9808232 polymorphism and the route of metastasis in HCC patients (P < 0.05). According to the Kaplan–Meier analysis, the overall survival of patients with AC and CC genotypes of ROCK2 rs9808232 was much shorter than that of patients with AA genotype (median overall survival, 25.5 months vs 16.0 months; Log rank P = 0.006). The overall survival time of patients with high ROCK2 expression is much shorter than that of patients with low ROCK2 expression (median overall survival time, 15.0 months vs 20.5 months; Log rank P = 0.008). Compared with genotype AA, the ROCK2 protein levels of genotypes AC and CC were distinctly increased in the HCC group, especially genotype CC (P< 0.05).

Conclusion

ROCK2 gene rs9808232 polymorphism may contribute to its expression in liver tissue, which may increase the susceptibility and poor prognosis of HCC.

Rho-Kinase as a Target for Cancer Therapy and Its Immunotherapeutic Potential

Cancer immunotherapy is fast rising as a prominent new pillar of cancer treatment, harnessing the immune system to fight against numerous types of cancer. Rho-kinase (ROCK) pathway is involved in diverse cellular activities, and is therefore the target of interest in various diseases at the cellular level including cancer. Indeed, ROCK is well-known for its involvement in the tumor cell and tumor microenvironment, especially in its ability to enhance tumor cell progression, migration, metastasis, and extracellular matrix remodeling. Importantly, ROCK is also considered to be a novel and effective modulator of immune cells, although further studies are needed. In this review article, we describe the various activities of ROCK and its potential to be utilized in cancer treatment, particularly in cancer immunotherapy, by shining a light on its activities in the immune system.

Role of RhoC in cancer cell migration

Migration is one of the five major behaviors of cells. Although RhoC—a classic member of the Rho gene family—was first identified in 1985, functional RhoC data have only been widely reported in recent years. Cell migration involves highly complex signaling mechanisms, in which RhoC plays an essential role. Cell migration regulated by RhoC—of which the most well-known function is its role in cancer metastasis—has been widely reported in breast, gastric, colon, bladder, prostate, lung, pancreatic, liver, and other cancers. Our review describes the role of RhoC in various types of cell migration. The classic two-dimensional cell migration cycle constitutes cell polarization, adhesion regulation, cell contraction and tail retraction, most of which are modulated by RhoC. In the three-dimensional cell migration model, amoeboid migration is the most classic and well-studied model. Here, RhoC modulates the formation of membrane vesicles by regulating myosin II, thereby affecting the rate and persistence of amoeba-like migration. To the best of our knowledge, this review is the first to describe the role of RhoC in all cell migration processes. We believe that understanding the detail of RhoC-regulated migration processes will help us better comprehend the mechanism of cancer metastasis. This will contribute to the study of anti-metastatic treatment approaches, aiding in the identification of new intervention targets for therapeutic or genetic transformational purposes.

CD24 gene inhibition and TIMP-4 gene upregulation by Imperata cylindrica's root extract prevents metastasis of CaSki cells via inhibiting PI3K/Akt/snail signaling pathway and blocking EMT

ETHNOPHARMACOLOGICAL RELEVANCE

Imperata cylindrica (L.) Raeusch (Gramineae) is a medicinal spice traditionally used in the treatment of hypertension and cancer.

AIM OF THE STUDY

To assess the anti-metastatic potential of the methanol extract of I. cylindrica roots and determined its mechanisms of action.

MATERIAL AND METHODS

The growth inhibition activity of I. cylindrica root extract in vitro and in vivo in human cervical cancer. The scratch assay and Boyden Chamber assay were used to determine the anti-migrative and anti-invasion actions of the plant extract. The whole-genome gene expression profiling using RNA-Seq was performed to determine the differentially expressed genes in CaSki cells after exposure to I. cylindrica to identify its targeted genes related to metastasis. Using protein analysis (western blotting) and gene expression analysis (RTqPCR), the targeted pathways of the key genes that were initially identified with RNA-Seq, were evaluated.

RESULTS

I. cylindrica extract showed dose-dependent cytotoxicity in vitro and in vivo in mice bearing tumors. Furthermore, I. cylindrica root extract significantly inhibited cell migration and cell invasion. After the genome-wide transcriptome analysis, we found that important genes involved in cancer progression and metastasis of cervical cancer, that is, CD24 and TIMP-4 were significantly downregulated and upregulated, respectively. Moreover, I. cylindrica root extract significantly inhibited the PI3/AKT/Snail signaling pathway and blocked the EMT of CaSki cells.

CONCLUSION

These findings provide an anti-metastatic mechanism of action of I. cylindrica root extract toward the human cervical cancer suggesting that this plant maybe developed into selective chemotherapy.

Synergic radiosensitization of sinomenine hydrochloride and radioiodine on human papillary thyroid carcinoma cells

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This is the first time to study and find out that sinomenine hydrochloride and iodine-131 synergic enhance the apoptosis and regulate DNA repair and cell cycle checkpoint on papillary thyroid carcinoma cells.

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This is the first time to study and find out that sinomenine hydrochloride increased the radiosensitivity of papillary thyroid carcinoma cells and normal thyroid cells.

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This is the first time to study and find out that sinomenine hydrochloride could be a potential therapeutic radiosensitizer in papillary thyroid carcinoma radiotherapy after total thyroidectomy .

Radioiodine (¹³¹I) therapy is an important treatment for thyroid carcinoma. The response to radiotherapy sometimes limited by the development of radioresistance. Sinomenine hydrochloride(SH), was reported as a prospective radiosensitizer. This study was aim to evaluate synergic radiosensitization of SH and ¹³¹I on papillary thyroid carcinoma (PTC). We evaluated HTori-3, BCPAP and TPC-1 cells, the cell viability was evaluated by MTT. The experiment was divided into 4 groups: control group, SH (0.8 mM) group, I (¹³¹I 14.8 MBq/ml) group and ISH (SH 0.8 mM plus ¹³¹I 14.8 MBq/ml) group. Flow cytometry was used to investigate cell cycle phases and cell apoptosis. RT-PCR and western blotting were performed to determine the molecular changes. Compared to control group, SH significantly increased apoptosis and enhanced radiosensitivity of HTori-3 and PTC cells were related to the ratio of Bcl-2 to Bax protein downregulation and Fas, p21, p-ATM, p-Chk1, p-Chk2 and p53 protein expression upregulation in the ISH group (P < 0.05). Our results indicate that synergic radiosensitization of SH and iodine-131 on PTC cells and SH could be a potential therapeutic radiosensitizer in PTC radio therapy after total thyroidectomy.

circNSUN2 promotes the malignant biological behavior of colorectal cancer cells via the miR‑181a‑5p/ROCK2 axis

Aberrant expression of circular RNAs (circRNAs) has been demonstrated to be related to the development of colorectal cancer (CRC), the third most common cancer worldwide. However, the mechanism of the effect of circRNA NOP2/Sun domain family, member 2 (circNSUN2) on the malignant biological behavior of CRC remains unclear. In the present study, the expression of circNSUN2 and microRNA (miR)‑181a‑5p was detected by RT‑qPCR. The expression of Rho‑associated coiled‑coil‑containing protein kinase 2 (ROCK2) was measured by western blotting. Cell proliferation was detected by CCK‑8 assay. The cell apoptosis rate was measured by flow cytometry. Cell migration ability was evaluated by Transwell assay. The interactions between circNSUN2, miR‑181a‑5p and ROCK2 were verified by dual‑luciferase reporter assay. The results revealed that circNSUN2 was highly expressed in CRC tissues and cell lines. Knockdown of circNSUN2 inhibited the malignant biological behavior of CRC in vivo and in vitro. Moreover, miR‑181a‑5p was revealed to be a target gene of circNSUN2, and the expression of ROCK2 was negatively regulated by miR‑181a‑5p. Knockdown of circNSUN2 inhibited proliferation and migration, and induced apoptosis of CRC cells and suppressed tumor growth by targeting miR‑181a‑5p to decrease ROCK2 expression. In conclusion, circNSUN2 promoted the progression of CRC by sponging miR‑181a‑5p to increase the expression of ROCK2.

Ras Homolog Family Member F, Filopodia Associated Promotes Hepatocellular Carcinoma Metastasis by Altering the Metabolic Status of Cancer Cells Through RAB3D

BACKGROUND AND AIMS

The mechanism by which tumor cells resist metabolic stress remains unclear, but many oncogenes are known to regulate this process. Accordingly, metabolic stress is closely associated with tumor metastasis. In this study, gene chip technology showed that Ras homolog family member F, filopodia associated (RHOF), a member of the Rho guanosine triphosphatase family, is an oncogene that is significantly related to hepatocellular carcinoma (HCC) metastasis; however, it has rarely been reported in tumors. Our aim was to determine the clinicopathological significance and role of RHOF in HCC progression and investigate the associated mechanisms.

APPROACH AND RESULTS

The results showed that compared to expression in adjacent noncancerous tissues, RHOF was frequently up-regulated in HCC tumor samples and elevated under conditions of glucose deprivation. RHOF expression was associated with tumor-node-metastasis stage, T grade, metastasis status, recurrence, and survival in HCC. RHOF also affected cell morphology and promoted migration, invasion, and epithelial-mesenchymal transition (EMT) of HCC cell lines. Analysis of the underlying mechanism showed that RHOF promoted the Warburg effect by up-regulating the expression and function of several glycolytic enzymes in HCC cells. This metabolic shift enhanced HCC cell migration and invasion. Specifically, RHOF exerted a tumor-promoting effect by directly interacting with AMP-activated protein kinase (AMPK) and increasing the phosphorylation of AMPK. This subsequently affected RAB3D mRNA stability and led to elevated RAB3D expression, thereby amplifying the Warburg effect and malignant biological behaviors of HCC cells.

CONCLUSIONS

RHOF helps tumor cells resist metabolic stress through modulating the Warburg effect and plays a critical role in promoting HCC cell migration, invasion, and EMT, highlighting its important role in remodeling the metastatic microenvironment and regulating tumor metastasis. RHOF shows potential as a therapeutic target and prognostic biomarker for HCC.

MRE11 as a molecular signature and therapeutic target for cancer treatment with radiotherapy

MRE11, the core of the MRE11/RAD50/NBS1 complex, is one of key DNA damage response proteins. Increasing evidence suggests that its expression in cancer cells is critical to developing radioresistance; as such, MRE11 is an emerging marker for targeted radiosensitization strategies. Elevated MRE11 in tumor tissues has been associated with poor survival in patients undergoing radiotherapy, although in some cancer types, the opposite has been noted. The recent discovery of ionizing radiation-induced truncation of MRE11, which decreases its efficacy, may explain some of these paradoxical findings. The progress of research on the biological modulation of MRE11 expression is also discussed, with the potential application of small molecule or large molecule inhibitors of MRE11 for enhancing radiosensitivity. Current research has further highlighted both nuclease and non-nuclease activities of MRE11 in cancer cells treated with ionizing radiation, and differentiation between these is essential to verify the targeting effects of radiosensitizing agents. These updates clarify our understanding of how MRE11 expression may be utilized in future stratification of cancer patients for radiotherapy, and how it may be leveraged in shaping novel radiosensitization strategies.

GTPases, genome, actin: A hidden story in DNA damage response and repair mechanisms

The classical small Rho GTPase (Rho, Rac, and Cdc42) protein family is mainly responsible for regulating cell motility and polarity, membrane trafficking, cell cycle control, and gene transcription. Cumulative recent evidence supports important roles for these proteins in the maintenance of genomic stability. Indeed, DNA damage response (DDR) and repair mechanisms are some of the prime biological processes that underlie several disease phenotypes, including genetic disorders, cancer, senescence, and premature aging. Many reports guided by different experimental approaches and molecular hypotheses have demonstrated that, to some extent, direct modulation of Rho GTPase activity, their downstream effectors, or actin cytoskeleton regulation contribute to these cellular events. Although much attention has been paid to this family in the context of canonical actin cytoskeleton remodeling, here we provide a contextualized review of the interplay between Rho GTPase signaling pathways and the DDR and DNA repair signaling components. Interesting questions yet to be addressed relate to the spatiotemporal dynamics of this collective response and whether it correlates with different subcellular pools of Rho GTPases. We highlight the direct and indirect targets, some of which still lack experimental validation data, likely associated with Rho GTPase activation that provides compelling evidence for further investigation in DNA damage-associated events and with potential therapeutic applications in translational medicine.

ROCK2 Promotes Osteosarcoma Growth and Glycolysis by Up-Regulating HKII via Phospho-PI3K/AKT Signalling

Background

Osteosarcoma (OS) is a malignant bone tumour that exhibits a high mortality. While tumours thrive in a state of malnutrition, the mechanism by which OS cells adapt to metabolic stress through metabolic reprogramming remains unclear.

Methods

We analysed the expression of ROCK2 in osteosarcoma tissues by RT-qPCR and Western blot. Cell proliferation were analysed using CCK8, EdU and colony formation assays. The level of cell glycolysis was detected by glucose-6 phosphate, glucose consumption, lactate production and ATP levels.

Results

Herein, our study showed that ROCK2 expression in OS tissues was higher than in adjacent tissues. Functional assays have demonstrated that ROCK2 contributes to the growth of OS cells by inducing aerobic glycolysis. The current study revealed that ROCK2 knockdown decreased the levels of mitochondrial hexokinase II (HKII). And also indicated that ROCK2 served as a key enzyme in glycolysis and that it served an important role in tumour growth. A significant positive correlation was identified between the mRNA and protein expressions of ROCK2 and HKII, further demonstrating that ROCK2-induced glycolysis and proliferation was dependent on HKII expression in OS cells. Mechanistically, ROCK2 promotes HKII expression by activating the phospho-PI3K/AKT signalling pathway.

Conclusion

Taken together, the results of the current study linked the two drivers of OS growth and aerobic glycolysis and identified a new mechanism of ROCK2 control in OS.

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

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

Rho GTPases in cancer radiotherapy and metastasis

Despite treatment advances, radioresistance and metastasis markedly impair the benefits of radiotherapy to patients with malignancies. Functioning as molecular switches, Rho guanosine triphosphatases (GTPases) have well-recognized roles in regulating various downstream signaling pathways in a wide range of cancers. In recent years, accumulating evidence indicates the involvement of Rho GTPases in cancer radiotherapeutic efficacy and metastasis, as well as radiation-induced metastasis. The functions of Rho GTPases in radiotherapeutic efficacy are divergent and context-dependent; thereby, a comprehensive integration of their roles and correlated mechanisms is urgently needed. This review integrates current evidence supporting the roles of Rho GTPases in mediating radiotherapeutic efficacy and the underlying mechanisms. In addition, their correlations with metastasis and radiation-induced metastasis are discussed. Under the prudent application of Rho GTPase inhibitors based on critical evaluations of biological contexts, targeting Rho GTPases can be a promising strategy in overcoming radioresistance and simultaneously reducing the metastatic potential of tumor cells.

Hyperoxia sensitizes hypoxic HeLa cells to ionizing radiation by downregulating HIF‑1α and VEGF expression

The current study investigated whether hyperoxia may reverse hypoxia-induced radioresistance (RR) in cervical cancer. Human HeLa cells exposed to hypoxic, normoxic or hyperoxic conditions were irradiated using X-rays. Cell proliferation and apoptosis were analyzed using MTT assays and flow cytometry. The expression levels of hypoxia-inducible factor-1α (HIF-1α), VEGF₁₆₅, VEGFRs, Akt and ERK were measured via western blotting and/or ELISA. The results demonstrated that hypoxia stimulated HIF-1α and VEGF expression, and induced RR in HeLa cells. The administration of recombinant VEGF or the forced expression of VEGF promoted RR, whereas inactivating HIF-1α or blocking the VEGF-VEGFR interaction abrogated hypoxia-induced RR. Notably, hyperoxia decreased the level of hypoxia-stimulated HIF-1α and VEGF, and enhanced radiosensitivity in hypoxic HeLa cells. The results demonstrated that hyperoxia suppressed the hypoxia-activated Akt and ERK signaling pathways in HeLa cells. Therefore, a high O₂ concentration may be considered as a radiotherapeutic sensitizer for hypoxic HeLa cells.

Rho GTPases in Gynecologic Cancers: In-Depth Analysis toward the Paradigm Change from Reactive to Predictive, Preventive, and Personalized Medical Approach Benefiting the Patient and Healthcare

Rho guanosine triphospatases (GTPases) resemble a conserved family of GTP-binding proteins regulating actin cytoskeleton dynamics and several signaling pathways central for the cell. Rho GTPases create a so-called Ras-superfamily of GTPases subdivided into subgroups comprising at least 20 members. Rho GTPases play a key regulatory role in gene expression, cell cycle control and proliferation, epithelial cell polarity, cell migration, survival, and apoptosis, among others. They also have tissue-related functions including angiogenesis being involved in inflammatory and wound healing processes. Contextually, any abnormality in the Rho GTPase function may result in severe consequences at molecular, cellular, and tissue levels. Rho GTPases also play a key role in tumorigenesis and metastatic disease. Corresponding mechanisms include a number of targets such as kinases and scaffold/adaptor-like proteins initiating GTPases-related signaling cascades. The accumulated evidence demonstrates the oncogenic relevance of Rho GTPases for several solid malignancies including breast, liver, bladder, melanoma, testicular, lung, central nervous system (CNS), head and neck, cervical, and ovarian cancers. Furthermore, Rho GTPases play a crucial role in the development of radio- and chemoresistance e.g. under cisplatin-based cancer treatment. This article provides an in-depth overview on the role of Rho GTPases in gynecological cancers, highlights relevant signaling pathways and pathomechanisms, and sheds light on their involvement in tumor progression, metastatic spread, and radio/chemo resistance. In addition, insights into a spectrum of novel biomarkers and innovative approaches based on the paradigm shift from reactive to predictive, preventive, and personalized medicine are provided.