IL-6 signaling contributes to cisplatin resistance in non-small cell lung cancer via the up-regulation of anti-apoptotic and DNA repair associated molecules

Yi Qi Chu Tan Formula (YQCTF) inhibited the progress of lung cancer via regulating tumor-associated neutrophil: An integrated study of network pharmacology, proteomics and pharmacodynamics

ETHNOPHARMACOLOGICAL RELEVANCE

Yi Qi Chu Tan Formula (YQCTF), a prescription consisting of eight traditional Chinese medicine for treating lung cancer, has been clinically proven to be effective in improving the life quality and prolonging the survival time of non-small cell lung cancer (NSCLC) patients.

AIM OF THE STUDY

This study aimed to evaluate the therapeutic efficacy of YQCTF on NSCLC mice model and further explore its therapeutic targets by using network pharmacology, proteomics and pharmacodynamic methodologies.

MATERIALS AND METHODS

The network pharmacology analysis was firstly conducted to screen out the potential active ingredients and therapeutic targets of YQCTF against NSCLC. Three kinds of extracts, i.e. the water extract (WE), water extraction-alcohol precipitation (WEAP) and alcohol extract (AE) of YQCTF were prepared, which chemical compositions were subsequently analyzed by using ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS), and which anti-neoplastic efficacy was examined on NSCLC mice model. Mice tumor tissues were collected for proteomics analysis, and the immunomodulatory effects of YQCTF extracts on the tumor microenvironment (TME) were further validated by using flow cytometry, immunofluorescence, ELISA and Western blot.

RESULTS

Network pharmacology identified 60 conjunct genes and ample cancer-related signaling pathways as potential therapeutic targets of YQCTF. Protein-protein interaction (PPI), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that YQCTF might negatively regulate cancer-related inflammation. UPLC-MS/MS analysis showed that the main components of YQCTF include at least ginsenosides, solasodine, solamargine, solasonine, peimisine, peiminine, peimine and sipeimine-3β-D-glucosihde. All kinds of YQCTF extracts significantly inhibited the growth of lung cancer allograft and regulated the ratio of immune cells in tumor tissues, i.e. upregulated the fractions of T cells, promoted the maturation of dendritic cells (DCs), increased the M1/M2 ratio of tumor-related macrophages, but reduced the number of Tregs and immunosuppressive neutrophils. Proteomics identified neutrophils to be the most prominently enriched target linked to NETs formation in mice tumor tissue, which is verified by the downregulation of neutrophil recruiting factors involving IL-6, HIF-1α and IL-8, as well as the decreases of NETs-related biomarkers including H3cit, MPO, CD18, MMP9 and ICAM-1 in immunofluorescence, ELISA and Western blot analysis.

CONCLUSION

YQCTF inhibited the progress of mice NSCLC allograft, suppressed the pro-tumorigenic tumor-associated neutrophils and improved the tumor immune microenvironment (TIME).

The use of non-steroid anti-inflammatory drugs during radical resection correlated with the outcome in non-small cell lung cancer

AIMS

The use of non-steroid anti-inflammatory drugs (NSAIDs) is conventional in management of postoperative pain in cancer patients, and further investigations have reported that some of these drugs correlated with the outcome in cancers. However, the prognostic value of the use of NSAIDs during surgery in non-small cell lung cancer (NSCLC) patients has been less addressed.

METHODS

NSCLC patients staged I-III are retrospectively enrolled, and the data of the use of NSAIDs during surgery are collected. Patients are divided into two subgroups according to the use intensity (UI) (low or high) of the NSAIDs, which was calculated by the accumulate dosage of all the NSAIDs divided by the length of hospitalization. The differences of the clinical features among these groups were checked. And the disease-free survival (DFS) and overall survival (OS) differences in these groups were compared by Kaplan-Meier analysis; risk factors for survival were validated by using a Cox proportional hazards model.

RESULTS

The UI was significant in predicting the DFS (AUC = 0.65, 95% CI: 0.57-0.73, P = 0.001) and OS (AUC = 0.70, 95% CI: 0.59-0.81, P = 0.001). Clinical features including type of resection (P = 0.001), N stages (P < 0.001), and TNM stages (P = 0.004) were significantly different in UI low (< 74.55 mg/day) or high (≥ 74.55 mg/day) subgroups. Patients in UI-high subgroups displayed significant superior DFS (log rank = 11.46, P = 0.001) and OS (log rank = 7.63, P = 0.006) than the UI-low ones. At last, the UI was found to be an independent risk factor for DFS (HR: 0.52, 95% CI: 0.28-0.95, P = 0.034).

CONCLUSIONS

The use of NSAIDs during radical resection in NSCLC patients correlated with the outcome and patients with a relative high UI has better outcome.

Lung cancer treatment potential and limits associated with the STAT family of transcription factors

Lung cancer is one of the mortal cancers and the leading cause of cancer-related mortality, with a cancer survival rate of fewer than 5% in developing nations. This low survival rate can be linked to things like late-stage detection, quick postoperative recurrences in patients receiving therapy, and chemoresistance developing against various lung cancer treatments. Signal transducer and activator of transcription (STAT) family of transcription factors are involved in lung cancer cell proliferation, metastasis, immunological control, and treatment resistance. By interacting with specific DNA sequences, STAT proteins trigger the production of particular genes, which in turn result in adaptive and incredibly specific biological responses. In the human genome, seven STAT proteins have been discovered (STAT1 to STAT6, including STAT5a and STAT5b). Many external signaling proteins can activate unphosphorylated STATs (uSTATs), which are found inactively in the cytoplasm. When STAT proteins are activated, they can increase the transcription of several target genes, which leads to unchecked cellular proliferation, anti-apoptotic reactions, and angiogenesis. The effects of STAT transcription factors on lung cancer are variable; some are either pro- or anti-tumorigenic, while others maintain dual, context-dependent activities. Here, we give a succinct summary of the various functions that each member of the STAT family plays in lung cancer and go into more detail about the advantages and disadvantages of pharmacologically targeting STAT proteins and their upstream activators in the context of lung cancer treatment.

A combined preoperative red cell distribution width and carcinoembryonic antigen score contribute to prognosis prediction in stage I lung adenocarcinoma

AIMS

Hematological markers that can be used for prognosis prediction for stage I lung adenocarcinoma (LUAD) are still lacking. Here, we examined the prognostic value of a combination of the red cell distribution width (RDW) and carcinoembryonic antigen (CEA), namely, the RDW-CEA score (RCS), in stage I LUAD.

MATERIALS AND METHODS

A retrospective study with 154 patients with stage I LUAD was conducted. Patients were divided into RCS 1 (decreased RDW and CEA), RCS 2 (decreased RDW and increased CEA, increased RDW and decreased CEA), and RCS 3 (increased RDW and CEA) subgroups based on the best optimal cutoff points of RDW and CEA for overall survival (OS). The differences in other clinicopathological parameters among RCS subgroups were calculated. Disease-free survival (DFS) and OS among these groups were determined by Kaplan-Meier analysis, and risk factors for outcome were calculated by a Cox proportional hazards model.

RESULTS

Seventy, 65, and 19 patients were assigned to the RCS 1, 2, and 3 subgroups, respectively. Patients ≥ 60 years (P < 0.001), male sex (P = 0.004), T₂ stage (P = 0.004), and IB stage (P = 0.006) were more significant in the RCS 2 or 3 subgroups. The RCS had a good area under the curve (AUC) for predicting DFS (AUC = 0.81, P < 0.001) and OS (AUC = 0.93, P < 0.001). The DFS (log-rank = 33.26, P < 0.001) and OS (log-rank = 42.05, P < 0.001) were significantly different among RCS subgroups, with RCS 3 patients displaying the worst survival compared to RCS 1 or 2 patients. RCS 3 was also an independent risk factor for both DFS and OS.

CONCLUSIONS

RCS is a useful prognostic indicator in stage I LUAD patients, and RCS 3 patients have poorer survival. However, randomized controlled trials are needed to validate our findings in the future.

S1P-Induced TNF-α and IL-6 Release from PBMCs Exacerbates Lung Cancer-Associated Inflammation

Sphingosine-1-phosphate (S1P) is involved in inflammatory signaling/s associated with the development of respiratory disorders, including cancer. However, the underlying mechanism/s are still elusive. The aim of this study was to investigate the role of S1P on circulating blood cells obtained from healthy volunteers and non-small cell lung cancer (NSCLC) patients. To pursue our goal, peripheral blood mononuclear cells (PBMCs) were isolated and stimulated with S1P. We found that the administration of S1P did not induce healthy PBMCs to release pro-inflammatory cytokines. In sharp contrast, S1P significantly increased the levels of TNF-α and IL-6 from lung cancer-derived PBMCs. This effect was S1P receptor 3 (S1PR3)-dependent. The pharmacological blockade of ceramidase and sphingosine kinases (SPHKs), key enzymes for S1P synthesis, completely reduced the release of both TNF-α and IL-6 after S1P addition on lung cancer-derived PBMCs. Interestingly, S1P-induced IL-6, but not TNF-α, release from lung cancer-derived PBMCs was mTOR- and K-Ras-dependent, while NF-κB was not involved. These data identify S1P as a bioactive lipid mediator in a chronic inflammation-driven diseases such as NSCLC. In particular, the higher presence of S1P could orchestrate the cytokine milieu in NSCLC, highlighting S1P as a pro-tumor driver.

Tumour invasion and dissemination

Activating invasion and metastasis are one of the primary hallmarks of cancer, the latter representing the leading cause of death in cancer patients. Whilst many advances in this area have been made in recent years, the process of cancer dissemination and the underlying mechanisms governing invasion are still poorly understood. Cancer cells exhibit multiple invasion strategies, including switching between modes of invasion and plasticity in response to therapies, surgical interventions and environmental stimuli. The ability of cancer cells to switch migratory modes and their inherent plasticity highlights the critical challenge preventing the successful design of cancer and anti-metastatic therapies. This mini-review presents current knowledge on the critical models of tumour invasion and dissemination. We also discuss the current issues surrounding current treatments and arising therapeutic opportunities. We propose that the establishment of novel approaches to study the key biological mechanisms underlying the metastatic cascade is critical in finding novel targets that could ultimately lead to complete inhibition of cancer cell invasion and dissemination.

circRNA_101277 Influences Cisplatin Resistance of Colorectal Cancer Cells by Modulating the miR-370/IL-6 Axis

Background. Colorectal cancer (CRC) is among the most prevalent malignancies globally. Early detection of precancerous lesions through routine colonoscopy has led to a dramatic reduction in CRC-related incidence and mortality among those between the ages of 50 and 70. However, in those where the disease progresses to an advanced stage, chemotherapy remains the primary available treatment option, and the associated 5-year survival rate remains low. The identification of genes associated with CRC chemoresistance would thus be a beneficial approach to identifying novel treatments for this deadly disease. Methods. The expression of circRNA_101277, miR-370, and IL-6 was assessed via qRT-PCR. IL-6 levels were measured with a human IL-6 ELISA kit based on the provided protocols. CRC cellular proliferation and cisplatin IC50 values were quantified via MTT assays. Luciferase assays were used to detect circRNA_101277 and miR-370 binding sites or miR-370 and IL-6 binding sites. Results. circRNA_101277 was increased in CRC tissues compared with control samples. circRNA_101277 overexpression was evident in CRC cells, and knockdown of this circRNA suppressed cellular proliferation and cisplatin resistance in these cancer cells. At a mechanistic level, circRNA_101277 was found to function by sequestering miR-370, thereby upregulating the miR-370 target gene IL-6 and promoting cisplatin resistance via this miR-370/IL-6 axis. Conclusion. In summary, our data highlight circRNA_101277 as a novel driver of CRC cell cisplatin resistance that functions by sequestering miR-370 and thereby enhancing IL-6 expression. These findings suggest that this circRNA_101277/miR-370/IL-6 axis may represent a critical axis of chemoresistance in CRC that can be targeted to diagnose and/or treat this cancer.

Pre-treatment immune status predicts disease control in NSCLCs treated with chemoradiation and durvalumab

BACKGROUND

The impact of peripheral blood immune measures and radiation-induced lymphopenia on outcomes in non-small cell lung cancer (NSCLC) patients treated with concurrent chemoradiation (cCRT) and immune check point inhibition (ICI) has yet to be fully defined.

METHODS

Stage III NSCLC patients treated with cCRT and ≥1 dose of durvalumab across a cancer center were examined. Peripheral blood counts were assessed pre-cCRT, during cCRT and at the start of ICI. These measures and risk-scores from two published models estimating radiation dose to immune-bearing organs were tested for association with disease control.

RESULTS

We assessed 113 patients treated with cCRT and a median of 8.5 months of durvalumab. Median PFS was 29 months (95% CI 18-35 months). A lower pre-cCRT ALC (HR: 0.51 (95% CI: 0.32-0.82), p = 0.02) and a higher pre-cCRT ANC (HR: 1.14 (1.06-1.23), p = 0.005) were associated with poor PFS. Neither ALC nadir, ALC at ICI start, ANC at ICI start or the normalized change in ALC from pre-cCRT to nadir were significantly associated with PFS (p = 0.07-0.49). Also, risk scores from the two radiation-dose models were not associated with PFS (p = 0.14, p = 0.21) but were so with the ALC Nadir (p = 0.001, p = 0.002). A higher pre-cCRT NLR was the strongest predictor for PFS (HR: 1.09 (1.05-1.14), p = 0.0001). The 12-month PFS in patients with the bottom vs. top NLR tertile was 84% vs 46% (p = 0.000004).

CONCLUSIONS

Baseline differences in peripheral immune cell populations are associated with disease outcomes in NSCLC patients treated with cCRT and ICI.

TIMP-2 regulates 5-Fu resistance via the ERK/MAPK signaling pathway in colorectal cancer

5-Fluorouracil (5-Fu) is the first-line chemotherapeutic option for colorectal cancer. However, its efficacy is inhibited by drug resistance. Cytokines play an important role in tumor drug resistance, even though their mechanisms are largely unknown. Using a cytokine array, we established that tissue inhibitor metalloproteinase 2 (TIMP-2) is highly expressed in 5-Fu resistant colorectal cancer patients. Analysis of samples from 84 patients showed that elevated TIMP-2 expression levels in colorectal patients were correlated with poor prognostic outcomes. In a 5-Fu-resistant patient-derived xenograft (PDX) model, TIMP-2 was also found to be highly expressed. We established an autocrine mechanism through which elevated TIMP-2 protein levels sustained colorectal cancer cell resistance to 5-Fu by constitutively activating the ERK/MAPK signaling pathway. Inhibition of TIMP-2 using an anti-TIMP-2 antibody or ERK/MAPK inhibition by U0126 suppressed TIMP-2 mediated 5-Fu-resistance in CRC patients. In conclusion, a novel TIMP-2-ERK/MAPK mediated 5-Fu resistance mechanism is involved in colorectal cancer. Therefore, targeting TIMP-2 or ERK/MAPK may provide a new strategy to overcome 5-Fu resistance in colorectal cancer chemotherapy.

Tumor Secretome to Adoptive Cellular Immunotherapy: Reduce Me Before I Make You My Partner

Adoptive cellular immunotherapy using chimeric antigen receptor (CAR)-modified T cells and Natural Killer (NK) cells are common immune cell sources administered to treat cancer patients. In detail, whereas CAR-T cells induce outstanding responses in a subset of hematological malignancies, responses are much more deficient in solid tumors. Moreover, NK cells have not shown remarkable results up to date. In general, immune cells present high plasticity to change their activity and phenotype depending on the stimuli they receive from molecules secreted in the tumor microenvironment (TME). Consequently, immune cells will also secrete molecules that will shape the activities of other neighboring immune and tumor cells. Specifically, NK cells can polarize to activities as diverse as angiogenic ones instead of their killer activity. In addition, tumor cell phagocytosis by macrophages, which is required to remove dying tumor cells after the attack of NK cells or CAR-T cells, can be avoided in the TME. In addition, chemotherapy or radiotherapy treatments can induce senescence in tumor cells modifying their secretome to a known as “senescence-associated secretory phenotype” (SASP) that will also impact the immune response. Whereas the SASP initially attracts immune cells to eliminate senescent tumor cells, at high numbers of senescent cells, the SASP becomes detrimental, impacting negatively in the immune response. Last, CAR-T cells are an attractive option to overcome these events. Here, we review how molecules secreted in the TME by either tumor cells or even by immune cells impact the anti-tumor activity of surrounding immune cells.

Pathogenesis and therapeutic strategy in platinum resistance lung cancer

Platinum compounds (cisplatin and carboplatin) represent the most active anticancer agents in clinical use both of lung cancer in mono-and combination therapies. However, platinum resistance limits its clinical application. It is necessary to understand the molecular mechanism of platinum resistance, identify predictive markers, and develop newer, more effective and less toxic agents to treat platinum resistance in lung cancer. Here, it summarizes the main molecular mechanisms associated with platinum resistance in lung cancer and the development of new approaches to tackle this clinically relevant problem. Moreover, it could lead to the development of more effective treatment for refractory lung cancer in future.

Role of cancer-associated fibroblasts in the resistance to antitumor therapy, and their potential therapeutic mechanisms in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a malignant tumor with high morbidity and mortality rates, which seriously endangers human health. Although treatment methods continue to evolve, the emergence of drug resistance is inevitable and seriously hinders the treatment of NSCLC. The tumor microenvironment (TME) protects tumor cells from the effects of chemotherapeutic drugs, which can lead to drug resistance. Cancer-associated fibroblasts (CAFs) are an important component of the TME, and various studies have demonstrated that CAFs play a crucial role in drug resistance in NSCLC. However, the drug resistance mechanism of CAFs and whether CAFs can be used as a target to reverse the resistance of tumor cells remain unclear. The present review discusses this issue and describes the heterogeneity of CAF markers, as well as their origins and resident organs, and the role and mechanism of this heterogeneity in NSCLC progression. Furthermore, the mechanism of CAF-mediated NSCLC resistance to chemotherapy, targeted therapy and immunotherapy is introduced, and strategies to reverse this resistance are described.

Cultivation of Head and Neck Squamous Cell Carcinoma Cells with Wound Fluid Leads to Cisplatin Resistance via Epithelial-Mesenchymal Transition Induction

Locoregional recurrence is a major reason for therapy failure after surgical resection of head and neck squamous cell carcinoma (HNSCC). The physiological process of postoperative wound healing could potentially support the proliferation of remaining tumor cells. The aim of this study was to evaluate the influence of wound fluid (WF) on the cell cycle distribution and a potential induction of epithelial-mesenchymal transition (EMT). To verify this hypothesis, we incubated FaDu and HLaC78 cells with postoperative WF from patients after neck dissection. Cell viability in dependence of WF concentration and cisplatin was measured by flow cytometry. Cell cycle analysis was performed by flow cytometry and EMT-marker expression by rtPCR. WF showed high concentrations of interleukin (IL)-6, IL-8, IL-10, CCL2, MCP-1, EGF, angiogenin, and leptin. The cultivation of tumor cells with WF resulted in a significant increase in cell proliferation without affecting the cell cycle. In addition, there was a significant enhancement of the mesenchymal markers Snail 2 and vimentin, while the expression of the epithelial marker E-cadherin was significantly decreased. After cisplatin treatment, tumor cells incubated with WF showed a significantly higher resistance compared with the control group. The effect of cisplatin-resistance was dependent on the WF concentration. In summary, proinflammatory cytokines are predominantly found in WF. Furthermore, the results suggest that EMT can be induced by WF, which could be a possible mechanism for cisplatin resistance.

PD-0332991 combined with cisplatin inhibits nonsmall cell lung cancer and reversal of cisplatin resistance

Background: Acquired resistance of chemotherapy, especially cisplatin, is a major challenge in lung cancer treatment. We conducted this study to examine whether a cyclin D kinase 4/6 (CDK4/6) inhibitor, PD 0332991, could reverse cisplatin resistance in human lung cancer cells. In addition, we explored the underlying mechanisms.

Method: We used CCK‐8 assay to got the IC50 of PD‐0332991 and cisplatin in A549 and A549/CDDP respectively. CCK‐8 assay, CalcuSyn 2.0 software, cell cycle distribution and apoptosis used to identify PD‐0332991 could reverse the acquired resistance of cisplatin. At last, western‐blot used to show the mechanism of PD‐0332991 enhances the effects of cisplatin.

Results: We found that PD‐0332991 potentiated cisplatin‐induced growth inhibition in both cisplatin‐sensitive (A549) and cisplatin‐resistant (A549/CDDP) cells via downregulation of the proliferation, induction of apoptosis (A549 increased to 7.06%; A549/CDDP increased to 7.03%), and G0/G1 cell cycle arrest (A549 increased to 9.15%; A549/CDDP increased to 49.92%). Western blot analysis revealed that PD‐0332991 enhance the effect of cisplatin through inhibit Rb‐E2Fs pathway.

Conclusions: These findings suggest that PD‐0332991 could reverse the acquired resistance of cisplatin in lung cancer cells and provide a novel treatment strategy for lung cancer patients with cisplatin resistance.

Down-regulation of GP130 signaling sensitizes bladder cancer to cisplatin by impairing Ku70 DNA repair signaling and promoting apoptosis

Chemoresistance is one of the barriers for the development of bladder cancer treatments. Previously, we showed that glycoprotein-130 (GP130) is overexpressed in chemoresistant bladder cancer cells and that knocking down GP130 expression reduced cell viability. In our current work, we showed that down-regulation of GP130 sensitized bladder cancer cells to cisplatin-based chemotherapy by activating DNA repair signaling. We performed immunohistochemistry and demonstrated a positive correlation between the levels of Ku70, an initiator of canonical non-homologous end joining repair (c-NHEJ) and suppressor of apoptosis, and GP130 in human bladder cancer specimens. GP130 knockdown by SC144, a small molecule inhibitor, in combination with cisplatin, increased the number of DNA lesions, specifically DNA double-stranded breaks, with a subsequent increase in apoptosis and reduced cell viability. Furthermore, GP130 inhibition attenuated Ku70 expression in bladder and breast cancer cells as well as in transformed kidney cells. In addition, we fabricated a novel polymer-lipid hybrid delivery system to facilitate GP130 siRNA delivery that had a similar efficiency when compared with Lipofectamine, but induced less toxicity.

Anti-tumor effects of mevalonate pathway inhibition in ovarian cancer

BACKGROUND

Ovarian cancer remains the most fatal gynecological malignancy. Current therapeutic options are limited due to late diagnosis in the majority of the cases, metastatic spread to the peritoneal cavity and the onset of chemo-resistance. Thus, novel therapeutic approaches are required. Statins and amino-bisphosphonates are inhibitors of the mevalonate pathway, which is a fundamental pathway of cellular metabolism, essential for cholesterol production and posttranslational protein farnesylation and geranylgeranylation. While this pathway has emerged as a promising treatment target in several human malignancies, its potential as a therapeutic approach in ovarian cancer is still not fully understood.

METHODS

Human ovarian cancer cell lines (IGROV-1, A2780, A2780cis) were treated with increasing concentrations (0.5-100 μM) of statins (simvastatin, atorvastatin, rosuvastatin) and zoledronic acid. Effects on cell vitality and apoptosis were assessed using Cell Titer Blue®, Caspase 3/7 Glo®, clonogenic assays as well as cleaved poly (ADP-ribose) polymerase (cPARP) detection. The inhibition of the mevalonate pathway was confirmed using Western Blot of unprenylated Ras and Rap1a proteins. Quantitative real-time PCR and ELISA were used to analyze modulations on several key regulators of ovarian cancer tumorigenesis.

RESULTS

The treatment of IGROV-1 and A2780 cells with statins and zoledronic acid reduced vitality (by up to 80%; p < 0.001) and induced apoptosis by up to 8-folds (p < 0.001) in a dose-dependent fashion. Rescue experiments using farnesyl pyrophosphate or geranylgeranyl pyrophosphate evidenced that blocked geranylgeranylation is the major underlying mechanism of the pro-apoptotic effects. Gene expression of the tumor-promoting cytokines and mediators, such as transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF), interleukin (IL)-8, and IL-6 were significantly suppressed by statins and zoledronic acid by up to 90% (p < 0.001). For all readouts, simvastatin was most potent of all agents used. Cisplatin-resistant A2780cis cells showed a relative resistance to statins and zoledronic acid. However, similar to the effects in A2780 cells, simvastatin and zoledronic acid significantly induced caspase 3/7 activation (6-folds; p < 0.001).

CONCLUSION

Our in vitro findings point to promising anti-tumor effects of statins and zoledronic acid in ovarian cancer and warrant additional validation in preclinical and clinical settings.

Cancer cells undergoing epigenetic transition show short-term resistance and are transformed into cells with medium-term resistance by drug treatment

To elucidate the epigenetic mechanisms of drug resistance, epigenetically reprogrammed H460 cancer cells (R-H460) were established by the transient introduction of reprogramming factors. Then, the R-H460 cells were induced to differentiate by the withdrawal of stem cell media for various durations, which resulted in differentiated R-H460 cells (dR-H460). Notably, dR-H460 cells differentiated for 13 days (13dR-H460 cells) formed a significantly greater number of colonies showing drug resistance to both cisplatin and paclitaxel, whereas the dR-H460 cells differentiated for 40 days (40dR-H460 cells) lost drug resistance; this suggests that 13dR-cancer cells present short-term resistance (less than a month). Similarly, increased drug resistance to both cisplatin and paclitaxel was observed in another R-cancer cell model prepared from N87 cells. The resistant phenotype of the cisplatin-resistant (CR) colonies obtained through cisplatin treatment was maintained for 2–3 months after drug treatment, suggesting that drug treatment transforms cells with short-term resistance into cells with medium-term resistance. In single-cell analyses, heterogeneity was not found to increase in 13dR-H460 cells, suggesting that cancer cells with short-term resistance, rather than heterogeneous cells, may confer epigenetically driven drug resistance in our reprogrammed cancer model. The epigenetically driven short-term and medium-term drug resistance mechanisms could provide new cancer-fighting strategies involving the control of cancer cells during epigenetic transition.

Cancer cells that are transiently resistant to drug therapies owing to changes in their gene expression patterns can become resistant for longer durations if exposed to the drug treatments. A team led by Kyeong-Man Hong and Hyonchol Jang from the National Cancer Center in Goyang, South Korea, used cellular reprogramming technologies to induce changes in the DNA markers that regulate gene expression. Working with lung and gastric cancer cell lines, the researchers found that such epigenetic alterations caused many cells to become resistant to the chemotherapy drugs cisplatin and paclitaxel. In the absence of treatment, the cells soon lost their drug resistance. In the presence of the chemotherapeutics, however, the resistance trait lasted longer, a finding that could inform best practice for how to administer cancer-fighting agents in the face of epigenetic-driven drug resistance.

Long Non-Coding RNA SLC25A21-AS1 Promotes Multidrug Resistance in Nasopharyngeal Carcinoma by Regulating miR-324-3p/IL-6 Axis

Background

Nasopharyngeal carcinoma (NPC), one of the most common types of head and neck tumor, occurred in the epithelial lining of the nasopharynx and is mainly prevalent in Southeast Asia and Southern China. However, the molecular mechanisms of NPC multidrug resistance still remained largely unclear.

Methods

The qRT-PCR assay was performed to examine SLC25A21-AS1, miR-324-3p and IL-6 expression in NPC tissues and cell. The CCK8 assay and colony formation assay were used to detect cell growth. In addition, CCK8 assay was performed to detect IC₅₀ values of different drugs in NPC cell.

Results

In this study, we found that SLC25A21-AS1 expression was increased in NPC tissues and cell line, and knockdown of SLC25A21-AS1 inhibited cell growth and MDR in NPC cell. Moreover, SLC25A21-AS1 acted as a ceRNA for miR-324-3p and facilitates NPC cell growth and MDR by regulating the miR-324-3p/IL-6 axis.

Conclusion

Our findings demonstrated the role of SLC25A21-AS1/miR-324-3p/IL-6 axis in cell growth and MDR in NPC, which might be a potential prognostic and diagnostic marker in NPC patients and provide new insight into the molecular mechanism of MDR in NPC chemotherapy.

4-methylumbelliferone inhibits clonogenic potency by suppressing high molecular weight-hyaluronan in fibrosarcoma cells

The inflammatory response is closely associated with cancer cell survival. It has been reported that inflammatory signaling cascades promote tumor survival and exert detrimental effects in normal tissue. Hyaluronans have different cellular functions depending on their molecular weights and high molecular weight-hyaluronan (HMW-HA) exhibits anti-inflammatory effects. A previous study determined that the co-administration of 4-methylumbelliferone (4-MU) and X-ray irradiation enhanced anti-tumor and anti-inflammatory effects in HT1080 human fibrosarcoma cells. However, many mechanisms underlie the effect of hyaluronan molecular weight on cells and the induction of anti-inflammatory effects via 4-MU. The present study aimed to determine the relationship between hyaluronan synthesis inhibition by 4-MU and its anti-inflammatory and radio-sensitizing effect in the context of hyaluronan molecular weight. The hyaluronan concentration following 2 Gy X-ray irradiation and/or 4-MU administration was analyzed via ELISA. Additionally, the mRNA expressions of hyaluronan synthase (HAS) by 4-MU and various inflammatory cytokines and interleukins (IL) following exogenous HMW-HA administration were evaluated via Reverse transcription-quantitative PCR. Invasive potential was assessed by matrigel transwell assays and cell survival following exposure to 4-MU with HMW-HA was determined using a clonogenic potency assay. The results of the present study demonstrated that 4-MU suppressed HMW-HA production by inhibiting HAS2 and HAS3 expression. In addition, the surviving fraction of fibrosarcoma cells were rescued from the cell-killing effect of 4-MU via the exogenous administration of HMW-HA. The mRNA levels of certain inflammatory cytokines, including IL-1α, IL-36γ and IL-37 were elevated following HMW-HA administration. The surviving fraction of cells irradiated with 2 Gy alone did not increase following exogenous HMW-HA administration. The results of the present study indicated that the radio-sensitizing effect of 4-MU and the inhibitory effect on hyaluronan synthesis were not closely associated. It was also revealed that IL-1α, IL-36γ and IL-37 were associated with the cell-killing effect of 4-MU in HT1080 cells.

Ameliorating effects of Gö6976, a pharmacological agent that inhibits protein kinase D, on collagen-induced arthritis

Toll-like receptor (TLR) signaling can contribute to the pathogenesis of arthritis. Disruption of TLR signaling at early stages of arthritis might thereby provide an opportunity to halt the disease progression and ameliorate outcomes. We previously found that Gö6976 inhibits TLR-mediated cytokine production in human and mouse macrophages by inhibiting TLR-dependent activation of protein kinase D1 (PKD1), and that PKD1 is essential for proinflammatory responses mediated by MyD88-dependent TLRs. In this study, we investigated whether PKD1 contributes to TLR-mediated proinflammatory responses in human synovial cells, and whether Gö6976 treatment can suppress the development and progression of type II collagen (CII)-induced arthritis (CIA) in mouse. We found that TLR/IL-1R ligands induced activation of PKD1 in human fibroblast-like synoviocytes (HFLS). TLR/IL-1R-induced expression of cytokines/chemokines was substantially inhibited in Gö6976-treated HFLS and PKD1-knockdown HFLS. In addition, serum levels of anti-CII IgG antibodies, and the incidence and severity of arthritis after CII immunization were significantly reduced in mice treated daily with Gö6976. Synergistic effects of T-cell receptor and TLR, as well as TLR alone, on spleen cell proliferation and cytokine production were significantly inhibited in the presence of Gö6976. Our results suggest a possibility that ameliorating effects of Gö6976 on CIA may be due to its ability to inhibit TLR/IL-1R-activated PKD1, which might play an important role in proinflammatory responses in arthritis, and that PKD1 could be a therapeutic target for inflammatory arthritis.

Granulocyte Colony-stimulating Factor- and Interleukin-6-producing Large-cell Carcinoma of the Lung with Sarcomatoid Changes Suggestive of Epithelial-mesenchymal Transition: An Autopsy Case Report

A rare case of lung cancer with the simultaneous production of granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6) is reported. A 79-year-old man was admitted to our hospital due to cachectic symptoms and an increased inflammatory response. Laboratory tests and imaging studies suggested metastatic lung cancer with high serum levels of G-CSF and IL-6. He died of progressive disease, and an autopsy showed that the lung tumor had positive protein expression of both cytokines and a solid growth of large-cell carcinoma with sarcomatoid changes, possibly resulting from the epithelial-mesenchymal transition mediated by IL-6 and leading to widespread metastases.

Monospecies and polymicrobial biofilms differentially regulate the phenotype of genotype-specific oral cancer cells

Microbial infection has been shown to involve in oral carcinogenesis; however, the underlying mechanisms remain poorly understood. The present study aimed to characterize the growth of oral microorganisms as both monospecies and polymicrobial biofilms and determine the effects of their products on oral keratinocytes. Candida albicans (ALC3), Actinomyces naeslundii (AN) and Streptococcus mutans (SM) biofilms or a combination of these (TRI) were grown in flow-cell system for 24 h. The biofilms were subjected to fluorescent in situ hybridization using species-specific probes and analysed using confocal laser scanning microscopy. The effluent derived from each biofilm was collected and incubated with malignant (H357) and normal (OKF6) oral keratinocytes to assess extracellular matrix adhesion, epithelial-mesenchymal transition (EMT) and cytokines expression. Incubation of OKF6 with ALC3 and TRI effluent significantly decreased adhesion of the oral keratinocyte to collagen I, whereas incubation of H357 with similar effluent increased adhesion of the oral keratinocyte to laminin I, significantly when compared with incubation with artificial saliva containing serum-free medium (NE; P < 0.05). In OKF6, changes in E-cadherin and vimentin expression were not consistent with EMT although there was evidence of a mesenchymal to epithelial transition in malignant oral keratinocytes incubated with AN and SM effluent. A significant increase of pro-inflammatory cytokines expression, particularly interleukin (IL)-6 and IL-8, was observed when H357 was incubated with all biofilm effluents after 2- and 24-h incubation when compared with NE (P < 0.05). In conclusion, C.albicans, A.naeslundii and S.mutans form polymicrobial biofilms which differentially modulate malignant phenotype of oral keratinocytes.

IL-22 Confers EGFR-TKI Resistance in NSCLC via the AKT and ERK Signaling Pathways

Background: The efficacy of an EGFR-targeted treatment strategy for non-small cell lung cancer (NSCLC) is reduced by drug resistance. IL-22 enhances tumor growth and induces chemotherapy resistance in human lung cancer cells. The present study elucidated the IL-22-induced mechanism underlying EGFR-tyrosine kinase inhibitor (TKI) resistance in NSCLC.

Methods: The plasma and tissues of patients who received EGFR-TKIs were utilized to determine the association between IL-22 expression and gefitinib efficacy. The IL-22 effect on the EGFR/ERK/AKT pathways in NSCLC HCC827 and PC-9 cells was determined using the CCK-8 assay, western blot, and flow cytometric analysis. A PC-9 xenograft model of IL-22 exposure was established. Gefitinib was administered to mice in combination with IL-22 or vehicle.

Results: We showed that IL-22 expression was higher in the EGFR-TKI-resistant group compared to EGFR-TKI-sensitive group. IL-22 expression was associated with EGFR-TKI efficacy in plasma. Additional treatment of IL-22 induced gefitinib resistance and reduced apoptosis in PC-9 and HCC827 cell lines. Furthermore, we showed that the effects of IL-22 attributed to p-ERK, p-EGFR, and p-AKT up-regulation. IL-22 neutralizing antibody completely abrogated the effects of IL-22 on apoptosis and AKT/EGFR/ERK signaling. Finally, we showed that IL-22 enhanced tumor growth and induced gefitinib resistance in the PC-9 xenograft model. Moreover, compared with gefitinib alone, the combination of IL-22 and gefitinib led to an increase in Ki67-positive staining and a reduction in TUNEL staining.

Conclusions: Our findings indicate that IL-22 plays a role in tumor progression and EGFR-TKI resistance in NSCLC. Thus, IL-22 might serve as a novel biomarker to overcome resistance of EGFR-TKI.

STAT3: A Potential Drug Target for Tumor and Inflammation

STAT (Signal Transducers and Activators of Transcription) is a cellular signal transcription factor involved in the regulation of many cellular activities, such as cell differentiation, proliferation, angiogenesis in normal cells. During the study of the STAT family, STAT3 was found to be involved in many diseases, such as high expression and sustained activation of STAT3 in tumor cells, promoting tumor growth and proliferation. In the study of inflammation, it was found that it plays an important role in the anti-inflammatory and repairing of damage tissues. Because of the important role of STAT3, a large number of studies have been obtained. At the same time, after more than 20 years of development, STAT3 has also been used as a target for drug therapy. And the discovery of small molecule inhibitors also promoted the study of STAT3. Since STAT3 has been extensively studied in inflammation and tumor regulation, this review presents the current state of research on STAT3.

Interleukin-6 mediates resistance to PI3K-pathway-targeted therapy in lymphoma

Background

The phosphoinositol 3-kinase (PI3K) pathway is associated with poor prognosis of hematologic malignancies, providing a strong rationale for the use of PI3K inhibitors in the treatment of malignant lymphoma. However, development of resistance limits the use of PI3K inhibitors in lymphoma patients.

Methods

We established copanlisib (pan-PI3K inhibitor)-resistant B-cell lymphoma and duvelisib (PI3Kδ and -γ inhibitor)-resistant T-cell lymphoma cell lines. The cytokine array and the phospho-kinase array were used to identify up-regulated proteins in the resistant cells. Cytokine expression and phospho-kinase levels were examined by ELISA and Western blot analysis, respectively. Cell proliferation capabilities were measured by using CCK-8 kit and colony formation assay. The effects of inhibitors on apoptosis were detected using an Annexin V-FITC Apoptosis Detection Kit and a flow cytometry system. The underlying mechanisms were studied by transfecting recombinant plasmids or siRNA into lymphoma cell lines. Cells were transiently transfected using the Amaxa electroporation system. We evaluated the effects of PI3K inhibitor alone and in combination with JAK inhibitor (BSK805) on lymphoma proliferation and signaling pathway activation.

Results

Cytokine arrays revealed upregulation of interleukin (IL)-6 in both copanlisib- and duvelisib-resistant cell lines. Phosphorylated STAT5, AKT, p70S6K and MAPK were increased in copanlisib-resistant B-cell lymphoma cells, whereas phosphorylated STAT3 and NF-κB were increased in duvelisib-resistant T cell lymphoma cells. Conversely, depletion of IL-6 sensitized both resistant cell lines, and led to downregulation of phosphorylated STAT3 and STAT5 in copanlisib- and duvelisib-resistant cells, respectively. Moreover, combined treatment with a JAK inhibitor (BSK805) and a PI3K inhibitor circumvented the acquired resistance to PI3K inhibitors in lymphoma, and concurrent inhibition of the activated pathways produced combined effects.

Conclusions

IL-6–induced STAT3 or STAT5 activation is a critical mechanism underlying PI3K inhibitor resistance in lymphoma, supporting the utility of IL-6 as an effective biomarker to predict therapeutic response to PI3K inhibitors.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6057-7) contains supplementary material, which is available to authorized users.

Epithelial-to-mesenchymal transition (EMT) to sarcoma in recurrent lung adenosquamous carcinoma following adjuvant chemotherapy

Adjuvant chemotherapy has long been indicated to extend survival in completely resected stage IB to IIIA non‐small cell lung cancer (NSCLC). However, there is accumulating evidence that chemotherapy or chemoradiotherapy can induce epithelial‐to‐mesenchymal transition (EMT) in disseminated or circulating NSCLC cells. Here, we describe the first case of EMT as the cause of recurrence and metastasis in a patient with resected stage IIB lung adenosquamous carcinoma after adjuvant chemotherapy. We review the literature and explore the possible mechanisms by which EMT occurs in disseminated tumor cells (DTC) or circulating tumor cells (CTC) in response to adjuvant chemotherapy (cisplatin) as a stressor. We also explore the possible therapeutic strategies to reverse EMT in patients with recurrence. In summary, although adjuvant cisplatin‐based chemotherapy in resected NSCLC does extend survival, it may lead to the adverse phenomenon of EMT in disseminated tumor cells (DTC) or circulating tumor cells (CTC) causing recurrence and metastasis.

Inflammation-induced DNA damage, mutations and cancer

The relationships between inflammation and cancer are varied and complex. An important connection linking inflammation to cancer development is DNA damage. During inflammation reactive oxygen and nitrogen species (RONS) are created to combat pathogens and to stimulate tissue repair and regeneration, but these chemicals can also damage DNA, which in turn can promote mutations that initiate and promote cancer. DNA repair pathways are essential for preventing DNA damage from causing mutations and cytotoxicity, but RONS can interfere with repair mechanisms, reducing their efficacy. Further, cellular responses to DNA damage, such as damage signaling and cytotoxicity, can promote inflammation, creating a positive feedback loop. Despite coordination of DNA repair and oxidative stress responses, there are nevertheless examples whereby inflammation has been shown to promote mutagenesis, tissue damage, and ultimately carcinogenesis. Here, we discuss the DNA damage-mediated associations between inflammation, mutagenesis and cancer.

Triptolide exerts an anti-tumor effect on non‑small cell lung cancer cells by inhibiting activation of the IL‑6/STAT3 axis

Lung cancer is the leading cause of cancer‑associated mortality and current treatments are not sufficiently effective. Numerous studies have revealed that triptolide (TP), a classical traditional Chinese medicine compound widely used as an anti‑inflammatory and antirheumatic drug, also has an antitumor effect. This effect is hypothesized to be mediated by multiple pathways, with signal transducer and activator of transcription 3 (STAT3) possibly one of them. Evidence indicates that STAT3 participates in the initiation and progression of lung cancer during cell proliferation, apoptosis and migration; however, whether and how TP affects STAT3 and its targets remain unclear. In this study, the potential role of TP in the proliferation, apoptosis, and migration of non‑small cell lung cancer cell lines was investigated and evaluated the impact of TP on the interleukin‑6 (IL‑6)/STAT3 axis. The results showed that TP inhibited cell proliferation and migration and induced apoptosis. TP decreased the phosphorylation of STAT3, inhibited STAT3 translocation into the nucleus, and reduced the expression of STAT3 target genes involved in cell survival, apoptosis and migration, e.g. C‑myc, BCL‑2, myeloid cell leukemia‑1 (MCL‑1), and matrix metallopeptidase 9 (MMP‑9). Additionally, IL‑6‑induced activation of STAT3 target genes (e.g. MCL‑1 and BCL‑2) was attenuated by TP and homoharringtonine. In conclusion, the effect of TP on STAT3 signaling points to a promising strategy for drug development.

Regulation of radiosensitivity by 4-methylumbelliferone via the suppression of interleukin-1 in fibrosarcoma cells

Tumor recurrence and distant metastasis following radiotherapy, which can lead to poor prognosis, are caused by residual cancer cells that acquire radioresistance. Chemotherapy or a combination of targeted inhibitors can potentially enhance radiation sensitivity and prevent metastasis. It was previously reported that co-administration of the hyaluronan synthesis inhibitor 4-methylumbelliferone (4-MU) enhanced the lethality of X-ray irradiation in HT1080 human fibrosarcoma cells and decreased their invasiveness to a greater extent than either treatment alone. To clarify the molecular basis of these effects, the present study conducted mRNA expression profiling by cDNA microarray to identify the signaling pathways that are altered under this combination treatment. The activation state of the signaling pathways was classified by z-scores in the Ingenuity Pathway Analysis. The results revealed that the pro-inflammatory cytokines interleukin (IL)-6 and IL-8 were activated by 2 Gy X-ray irradiation, an effect that was abolished by co-administration of 4-MU. Similar trends were observed for the upstream signaling component IL-1. These results indicate that the radiosensitivity of fibrosarcoma cells is improved by suppressing inflammation through the administration of 4-MU.

Chemotherapy and Inflammatory Cytokine Signalling in Cancer Cells and the Tumour Microenvironment

Cancer is the result of a cell's acquisition of a variety of biological capabilities or 'hallmarks' as outlined by Hanahan and Weinberg. These include sustained proliferative signalling, the ability to evade growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and the ability to invade other tissue and metastasize. More recently, the ability to escape immune destruction has been recognized as another important hallmark of tumours. It is suggested that genome instability and inflammation accelerates the acquisition of a variety of the above hallmarks. Inflammation, is a product of the body's response to tissue damage or pathogen invasion. It is required for tissue repair and host defense, but prolonged inflammation can often be the cause for disease. In a cancer patient, it is often unclear whether inflammation plays a protective or deleterious role in disease progression. Chemotherapy drugs can suppress tumour growth but also induce pathways in tumour cells that have been shown experimentally to support tumour progression or, in other cases, encourage an anti-tumour immune response. Thus, with the goal of better understanding the context under which each of these possible outcomes occurs, recent progress exploring chemotherapy-induced inflammatory cytokine production and the effects of cytokines on drug efficacy in the tumour microenvironment will be reviewed. The implications of chemotherapy on host and tumour cytokine pathways and their effect on the treatment of cancer patients will also be discussed.

Constitutional mismatch repair-deficiency: current problems and emerging therapeutic strategies

Mismatch repair (MMR) proteins remove errors from newly synthesized DNA, improving the fidelity of DNA replication. A loss of MMR causes a mutated phenotype leading to a predisposition to cancer. In the last 20 years, an increasing number of patients have been described with biallelic MMR gene mutations in which MMR defects are inherited from both parents. This leads to a syndrome with recessive inheritance, referred to as constitutional mismatch repair-deficiency (CMMRD). CMMRD is a rare childhood cancer predisposition syndrome. The spectrum of CMMRD tumours is broad and CMMRD-patients possess a high risk of multiple cancers including hematological, brain and intestinal tumors. The severity of CMMRD is highlighted by the fact that patients do not survive until later life, emphasising the requirement for new therapeutic interventions. Many tumors in CMMRD-patients are hypermutated leading to the production of truncated protein products termed neoantigens. Neoantigens are recognized as foreign by the immune system and induce antitumor immune responses. There is growing evidence to support the clinical efficacy of neoantigen based vaccines and immune checkpoint inhibitors (collectively referred to as immunotherapy) for the treatment of CMMRD cancers. In this review, we discuss the current knowledge of CMMRD, the advances in its diagnosis, and the emerging therapeutic strategies for CMMRD-cancers.

A preclinical model to investigate the role of surgically-induced inflammation in tumor responses to intraoperative photodynamic therapy

OBJECTIVE

Inflammation is a well-known consequence of surgery. Although surgical debulking of tumor is beneficial to patients, the onset of inflammation in injured tissue may impede the success of adjuvant therapies. One marker for postoperative inflammation is IL-6, which is released as a consequence of surgical injuries. IL-6 is predictive of response to many cancer therapies, and it is linked to various molecular and cellular resistance mechanisms. The purpose of this study was to establish a murine model by which therapeutic responses to photodynamic therapy (PDT) can be studied in the context of surgical inflammation.

MATERIALS AND METHODS

Murine models with AB12 mesothelioma tumors were treated with either surgical resection or sham surgery with tumor incision but no resection. The timing and extent of IL-6 release in the tumor and/or serum was measured using enzyme-linked immunosorbent assay (ELISA) and compared to that measured in the serum of 27 consecutive, prospectively enrolled patients with malignant pleural mesothelioma (MPM) who underwent macroscopic complete resection (MCR).

RESULTS

MPM patients showed a significant increase in IL-6 at the time MCR was completed. Similarly, IL-6 increased in the tumor and serum of mice treated with surgical resections. However, investigations that combine resection with another therapy make it necessary to grow tumors for resection to a larger volume than those that receive secondary therapy alone. As the larger size may alter tumor biology independent of the effects of surgical injury, we assessed the tumor incision model. In this model, tumor levels of IL-6 significantly increased after tumor incision.

CONCLUSION

The tumor incision model induces IL-6 release as is seen in the surgical setting, yet it avoids the limitations of surgical resection models. Potential mechanisms by which surgical induction of inflammation and IL-6 could alter the nature and efficacy of tumor response to PDT are reviewed. These include a wide spectrum of molecular and cellular mechanisms through which surgically-induced IL-6 could change the effectiveness of therapies that are combined with surgery. The tumor incision model can be employed for novel investigations of the effects of surgically-induced, acute inflammation on therapeutic response to PDT (or potentially other therapies). Lasers Surg. Med. 50:440-450, 2018. © 2018 Wiley Periodicals, Inc.

STAT3 and apoptosis challenges in cancer

Several studies have processed conceivable evidence for the vital role of Signal Transducer and Activator of Transcription 3 (STAT3) in cancer transformation and carcinogenesis. Therefore, one of the important factors in formation of cancer is STAT3 and for design of novel anticancer drugs is a suitable target. On the other hand, apoptosis pathway has a critical role in the cancers pathogenesis. Generally, increasing developments have been existed to expression, production, phosphorylation or activation of STAT3 in the effective or responsible cells of most of the cancers. In return, apoptosis process in this cells have been suffered inhibition, decrease in expression, produce or activation in some related factors which lead to debilitation or inhibition of the process. Further understanding of the STAT3 related signaling and apoptosis pathway can lead to the invention of novel approaches for therapies in unstudied disease. In this manuscript, review and highlight recent knowledge of the STAT3 pathway and its connection with apoptosis process in cancers and discuss STAT3-targeting agents to therapeutic developments.

IRF9 and unphosphorylated STAT2 cooperate with NF-κB to drive IL6 expression

We describe unexpected cooperation between two cytokines that are important in regulating the growth of cancers, namely, type I interferons (IFNs) and interleukin 6 (IL6). It is well established that IL6 is vital for the ability of many tumor types to prosper, and the work in the current paper reveals that the signaling pathway driven by IFN, which is also evident in many cancers, increases the expression of IL6 through a direct effect on the IL6 gene. The findings may help to identify new antitumor targets for therapy.

In response to IFNβ, the IL6 gene is activated, modestly at early times by ISGF3 (IRF9 plus tyrosine-phosphorylated STATs 1 and 2), and strongly at late times by U-ISGF3 (IRF9 plus U-STATs 1 and 2, lacking tyrosine phosphorylation). A classical IFN-stimulated response element (ISRE) at −1,513 to −1,526 in the human IL6 promoter is required. Pretreating cells with IFNβ or increasing the expression of U-STAT2 and IRF9 exogenously greatly enhances IL6 expression in response to the classical NF-κB activators IL1, TNF, and LPS. U-STAT2 binds tightly to IRF9, the DNA binding subunit of ISGF3, and also to the p65 subunit of NF-κB. Therefore, as shown by ChIP analyses, U-STAT2 can bridge the ISRE and κB elements in the IL6 promoter. In some cancer cells, the protumorigenic activation of STAT3 will be enhanced by the increased synthesis of IL6 that is facilitated by high expression of U-STAT2 and IRF9.

A FASN-TGF-β1-FASN regulatory loop contributes to high EMT/metastatic potential of cisplatin-resistant non-small cell lung cancer

Cisplatin-resistant A549CisR and H157CisR cell lines were developed by treating parental A549 (A549P) and H157 (H157P) cells. These cisplatin-resistant cells showed slight growth retardation, but exhibited higher epithelial-mesenchymal transition (EMT) and increased metastatic potential compared to parental cells. We observed a highly up-regulated fatty acid synthase (FASN) level in A549CisR and H157CisR cells compared to parental cells and the up-regulation of FASN was also detected in A549P and H157P cells after short time treatment with cisplatin, suggesting that the high level of FASN in cisplatin-resistant cells may be from the accumulated cellular responses during cisplatin-resistance developmental process. We next investigated whether the inhibition of FASN by using a specific FASN inhibitor, cerulenin, can influence growth and EMT/metastatic potential of A549CisR and H157CisR cells. There was slight growth inhibition, but significantly reduced EMT/metastatic potential in cisplatin-resistant cells upon inhibitor treatment. The in vitro result was further investigated in orthotopic xenograft mouse models established with luciferase-tagged H157P and H157CisR cells. Mice were injected with cerulenin or vehicle after tumors were developed. No significant tumor regression was detected at the end of cerulenin treatment, but IHC staining showed higher expression of EMT/metastasis markers in H157CisR cell-derived tumors than H157P cell-derived tumors, and showed dramatic reduction of these markers in tumor tissues of cerulenin-treated mice, confirming the in vitro results. In mechanism dissection studies, we revealed the existence of the FASN-TGF-β1-FASN positive loop in A549CisR and H157CisR cells, but not in parental cells, which is believed to augment the FASN function in cisplatin-resistant cells.

Caveolin-1-mediated STAT3 activation determines electrotaxis of human lung cancer cells

Migration of cancer cells leads to the invasion of distant organs by primary tumors. Further, endogenous electric fields (EFs) in the tumor microenvironment direct the migration of lung cancer cells by a process referred to as electrotaxis – although the precise mechanism remains unclear. Caveolin-1 (Cav-1) is a multifunctional scaffolding protein that is associated with directional cell migration and lung cancer invasion; however, its precise role in lung cancer electrotaxis is unknown. In the present study, we first detected outward electric currents on the tumor body surface in lung cancer xenografts using a highly-sensitive vibrating probe. Next, we found that highly-metastatic H1650-M3 cells migrated directionally to the cathode. In addition, reversal of the EF polarity reversed the direction of migration. Mechanistically, EFs activated Cav-1 and the downstream signaling molecule STAT3. RNA interference of Cav-1 reduced directional cell migration, which was accompanied by dampened STAT3 activation. Furthermore, pharmacological inhibition of STAT3 significantly reduced the electrotactic response, while rescue of STAT3 activation in Cav-1 knock-down cells restored electrotaxis. Taken together, these results suggest that endogenous EFs in the tumor micro-environment might play an important role in lung cancer metastasis by guiding cell migration through a Cav-1/STAT3-mediated signaling pathway.

Enhancing NK cell-mediated cytotoxicity to cisplatin-resistant lung cancer cells via MEK/Erk signaling inhibition

Major progress has been made clinically in inhibiting the programmed death receptor 1 (PD-1)/PD-L1 interaction to enhance T cell-mediated immune function, yet the effectiveness of anti-PD-L1/PD-1 agents in enhancing natural killer (NK) cell’s function remains largely unknown. Susceptibilities of cisplatin-resistant A549CisR and H157CisR cells vs. parental cells to the cytotoxic action of NK cells were examined. We found cisplatin-resistant cells more resistant to NK cell cytotoxicity than parental cells. There were constitutively higher expressions of PD-L1 in A549CisR and H157CisR cells than in parental cells in vitro, as well as in H157CisR cell-derived tumors than H157P cell-derived tumors. In contrast, we observed that the expression of PD-1 in NK cells was induced after co-culture with cisplatin-resistant cells. We also observed increased susceptibility of cisplatin-resistant cells to NK cell cytotoxicity when neutralizing antibody of PD-1 or PD-L1 was added. Further, we found that the NK group 2, member D (NKG2D) ligand levels were lower in A549CisR and H157CisR cells than in parental cells. Meanwhile, we discovered that the MEK/Erk signaling pathway played a significant role in this regulation, and the addition of a MEK/Erk pathway inhibitor significantly enhanced the PD-L1 Ab effect in enhancing NK cell cytotoxicity to cisplatin-resistant cells.

Simultaneous targeting of ATM and Mcl-1 increases cisplatin sensitivity of cisplatin-resistant non-small cell lung cancer

Development of cisplatin-resistance is an obstacle in non-small cell lung cancer (NSCLC) therapeutics. To investigate which molecules are associated with cisplatin-resistance, we analyzed expression profiles of several DNA repair and anti-apoptosis associated molecules in parental (A549P and H157P) and cisplatin-resistant (A549CisR and H157CisR) NSCLC cells. We detected constitutively upregulated nuclear ATM and cytosolic Mcl-1 molcules in cisplatin-resistant cells compared with parental cells. Increased levels of phosphorylated ATM (p-ATM) and its downstream molecules, CHK2, p-CHK2, p-53, and p-p53 were also detected in cisplatin-resistant cells, suggesting an activation of ATM signaling in these cells. Upon inhibition of ATM and Mcl-1 expression/activity using specific inhibitors of ATM and/or Mcl-1, we found significantly enhanced cisplatin-cytotoxicity and increased apoptosis of A549CisR cells after cisplatin treatment. Several A549CisR-derived cell lines, including ATM knocked down (A549CisR-siATM), Mcl-1 knocked down (A549CisR-shMcl1), ATM/Mcl-1 double knocked down (A549CisR-siATM/shMcl1) as well as scramble control (A549CisR-sc), were then developed. Higher cisplatin-cytotoxicity and increased apoptosis were observed in A549CisR-siATM, A549CisR-shMcl1, and A549CisR-siATM/shMcl1 cells compared with A549CisR-sc cells, and the most significant effect was shown in A549CisR-siATM/shMcl1 cells. In in vivo mice studies using subcutaneous xenograft mouse models developed with A549CisR-sc and A549CisR-siATM/shMcl1 cells, significant tumor regression in A549CisR-siATM/shMcl1 cells-derived xenografts was observed after cisplatin injection, but not in A549CisR-sc cells-derived xenografts. Finally, inhibitor studies revealed activation of Erk signaling pathway was most important in upregulation of ATM and Mcl-1 molcules in cisplatin-resistant cells. These studies suggest that simultaneous blocking of ATM/Mcl-1 molcules or downstream Erk signaling may recover the cisplatin-resistance of lung cancer.

Inhibition of STAT3 with the Generation 2.5 Antisense Oligonucleotide, AZD9150, Decreases Neuroblastoma Tumorigenicity and Increases Chemosensitivity

Purpose: Neuroblastoma is a pediatric tumor of peripheral sympathoadrenal neuroblasts. The long-term event-free survival of children with high-risk neuroblastoma is still poor despite the improvements with current multimodality treatment protocols. Activated JAK/STAT3 pathway plays an important role in many human cancers, suggesting that targeting STAT3 is a promising strategy for treating high-risk neuroblastoma.Experimental Design: To evaluate the biologic consequences of specific targeting of STAT3 in neuroblastoma, we assessed the effect of tetracycline (Tet)-inducible STAT3 shRNA and the generation 2.5 antisense oligonucleotide AZD9150 which targets STAT3 in three representative neuroblastoma cell line models (AS, NGP, and IMR32).Results: Our data indicated that Tet-inducible STAT3 shRNA and AZD9150 inhibited endogenous STAT3 and STAT3 target genes. Tet-inducible STAT3 shRNA and AZD9150 decreased cell growth and tumorigenicity. In vivo, STAT3 inhibition by Tet-inducible STAT3 shRNA or AZD9150 alone had little effect on growth of established tumors. However, when treated xenograft tumor cells were reimplanted into mice, there was a significant decrease in secondary tumors in the mice receiving AZD9150-treated tumor cells compared with the mice receiving ntASO-treated tumor cells. This indicates that inhibition of STAT3 decreases the tumor-initiating potential of neuroblastoma cells. Furthermore, inhibition of STAT3 significantly increased neuroblastoma cell sensitivity to cisplatin and decreased tumor growth and increased the survival of tumor-bearing mice in vivoConclusions: Our study supports the development of strategies targeting STAT3 inhibition in combination with conventional chemotherapy for patients with high-risk neuroblastoma. Clin Cancer Res; 23(7); 1771-84. ©2016 AACR.

Krüppel-Like Factor 4 Enhances Sensitivity of Cisplatin to Lung Cancer Cells and Inhibits Regulating Epithelial-to-Mesenchymal Transition

In order to improve therapeutic efficacy, it is a current emergency to better know the mechanisms underlying cisplatin resistance in lung cancer cells. In this study, we aim to investigate the role of Krüppel-like factor 4 (KLF4) in cisplatin-resistant lung cancer cells. We developed cisplatin-resistant lung cancer cell line A549/DDP, and then a battery of experiments was used to analyze the effects of KLF4 in cisplatin resistance of lung cancer. We found that KLF4 was significantly downregulated in cisplatin-resistant A549 cells and forced KLF4 expression inhibited cell growth and induced apoptosis. Further, we found that overexpression of KLF4 was able to inhibit cell migration and invasion, to inhibit the expression of Slug, Twist, and vimentin, and to increase the expression of E-cadherin and subsequent inhibition of the EMT process. Thus, overexpression of KLF4 may be a potential strategy for lung cancer treatment, especially for cisplatin-resistant cases.

IL-6 Mediates Macrophage Infiltration after Irradiation via Up-regulation of CCL2/CCL5 in Non-small Cell Lung Cancer

Radiotherapy is effective in reducing primary tumors, however, it may enhance macrophage infiltration to tumor sites, accelerating tumor progression in several ways. We investigated whether radiation can increase macrophage infiltration into non-small cell lung carcinoma (NSCLC) cells. Analysis of in vitro macrophage (differentiated THP-1 cells) migration to either nonirradiated or irradiated tumor cells showed increased migration to the irradiated tumor cells. Because the IL-6 levels in A549 and H157 cells were significantly increased after irradiation, we then investigated whether this increased IL-6 level contributes to radiation-induced macrophage migration. Radiation-induced macrophage infiltration was reduced when IL-6 was knocked down in tumor cells, indicating a positive IL-6 role in this process. To validate this in vitro result, an orthotopic mouse model was developed using a luciferase-tagged H157siIL-6/scramble control (sc) cell set. After tumors developed, the lungs were irradiated, and infiltration of endogenous macrophages and tail-vein injected fluorescent macrophages to tumor sites was investigated. In both groups, increased macrophage infiltration was observed in H157sc cell-derived xenografts compared to H157siIL-6 cell-derived xenografts, confirming the positive IL-6 role in the radiation-induced macrophage infiltration process. In mechanistic dissection studies, radiation-induced up-regulation of CCL2 and CCL5 by IL-6 was detected, and blocking the action of CCL2/CCL5 molecules significantly reduced the number of migrated macrophages to tumor cells after irradiation. These results demonstrate that targeting the IL-6 signaling or CCL2/CCL5 molecules in combination with conventional radiotherapy potentially blocks undesired radiation-induced macrophage infiltration.

IL-6 promotes growth and epithelial-mesenchymal transition of CD133+ cells of non-small cell lung cancer

We examined IL-6 effects on growth, epithelial-mesenchymal transition (EMT) process, and metastatic ability of CD133+ and CD133– cell subpopulations isolated from three non-small cell lung cancer (NSCLC) cell lines: A549, H157, and H1299. We developed IL-6 knocked-down and scramble (sc) control cells of A549 and H157 cell lines by lentiviral infection system, isolated CD133+ and CD133– sub-populations, and investigated the IL-6 role in self-renewal/growth of these cells. IL-6 showed either an inhibitory or lack of effect in modulating growth of CD133– cells depending on intracellular IL-6 levels, but there was higher self-renewal ability of IL-6 expressing CD133+ cells than IL-6 knocked down cells, confirming the promoter role of IL-6 in CD133+ cells growth. We then examined tumor growth of xenografts developed from CD133+ cells of A549IL-6si vs. A549sc cell lines. Consistently, there was retarded growth of tumors developed from A549IL-6si, CD133+ cells compared to tumors originating from A549sc, CD133+ cells. The effect of IL-6 in promoting CD133+ self-renewal was due to hedgehog (Hhg) and Erk signaling pathway activation and higher Bcl-2/Bcl-xL expression. We also investigated whether IL-6 regulates the EMT process of CD133− and CD133+ cells differently. Expression of the EMT/metastasis-associated molecules in IL-6 expressing cells was higher than in IL-6 knocked down cells. Together, we demonstrated dual roles of IL-6 in regulating growth of CD133– and CD133+ subpopulations of lung cancer cells and significant regulation of IL-6 on EMT/metastasis increase in CD133+ cells, not in CD133– cells.

Sageone, a diterpene from Rosmarinus officinalis, synergizes with cisplatin cytotoxicity in SNU-1 human gastric cancer cells

BACKGROUND AND PURPOSE

Chemotherapy resistance is a major obstacle for the effective treatment of cancers. Although several studies have described the anticancer properties of rosemary extract and its components, the detailed mechanisms of action are poorly understood.

METHODS

Activity-guided fractionation and repeated chromatographic separation of the n-hexane fraction of the aqueous methanol extract over silica gel, RP C18, and Sephadex LH-20 led to the isolation of three compounds. The structures of the compounds were determined using ¹H, ¹³C, and two-dimensional nuclear magnetic resonance spectroscopy, mass spectroscopy, and infrared spectroscopy. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to evaluate the cytotoxicity of these compounds. Cell cycle, apoptotic cell populations, and mitochondrial membrane potential were analyzed by flow cytometry. Western blot analysis was conducted to detect apoptosis-related proteins.

RESULTS

An abietane diterpenoid, sageone (1), an icetexane diterpenoid, (-)-barbatusol (2), and a monoterpene, (+)-verbenone (3), were identified. Of these compounds, sageone (1) showed cytotoxicity against SNU-1 cells with an IC₅₀ of 9.45 ± 1.33 µM. Sageone reduced the expression of Akt dramatically, as opposed to cisplatin, which increased phosphorylated Akt. Sageone combined with a subtoxic dose of cisplatin had synergistic effects on apoptosis induction in SNU-1 cells, as confirmed by calculating the combination index. Co-treatment was significantly more effective than monotherapy at reducing cell viability and inducing apoptosis, as determined by analyzing DNA fragmentation. The combined treatment of sageone and cisplatin markedly reduced Akt expression and phosphorylation, accompanied by increases in cleaved caspase-3, -9 and PARP.

CONCLUSION

This is the first time compounds 1 and 2 have been isolated from R. officinalis. Sageone induced apoptosis in SNU-1 human gastric cancer cells and notably enhanced the cytotoxicity of cisplatin in SNU-1 cells, which are known to be resistant to cisplatin. These findings suggest that sageone represents a promising anticancer agent against gastric cancer that warrants further study.

Baicalin attenuates DDP (cisplatin) resistance in lung cancer by downregulating MARK2 and p-Akt

DDP (cisplatin) resistance in lung cancer has been widely reported. Baicalin is a flavone glycoside found in genus Scutellaria. However, the effects of baicalin on DDP resistance in lung cancer are unclear. The aim of present study was to investigate effects of combination of baicalin and DDP on proliferation and invasion of human lung cancer cells, and explore possible mechanisms. MTT assay was utilized to evaluate effects of baicalin and DDP on the proliferation of A549 and A549/DPP (DPP-resistant) human lung cancer cells. The probability sum method was used to determine effects of the drug combination. Transwell invasion assay was utilized to detect tumor cell invasion. The mRNA expression of MARK2 in A549 and A549/DPP cells was detected by qPCR. Protein expression of MARK2, p-Akt and Akt was detected by western blot analysis. Baicalin and DPP when used alone inhibited the proliferation of A549 and A549/DDP cells in a dose-dependent manner at 24 and 48 h. For A549 cells, baicalin (8 µg/ml) antagonized DDP (1, 2, 4 and 8 µg/ml) at 24 h. For A549/DDP cells, baicalin and DDP were additive when the concentration of DDP was 4 µg/ml at 24 h. Effects of baicalin and DDP on proliferation inhibition were additive and synergistic when concentrations of DDP were 8 and 4 µg/ml, respectively, at 48 h for both A549 and A549/DDP cells. When baicalin (8 µg/ml) and DDP (4 µg/ml) were combined, the inhibitory rate of tumor cell invasion increased markedly compared to DPP or baicalin alone groups in both A549 and A549/DDP cells. A549/DDP cells had significantly higher MARK2 mRNA levels and protein expression of MARK2 and p-Akt. Baicalin decreased MARK2 mRNA and protein expression of MARK2 and p-Akt in A549/DDP cells dose-dependently. In conclusion, baicalin and DDP were synergistic at inhibiting proliferation and invasion of human lung cancer cells at appropriate dosages and incubation time in the presence or absence of DDP resistance. The attenuation of DDP resistance was associated with downregulation of MARK2 and p-Akt.

Combination of gambogic acid with cisplatin enhances the antitumor effects on cisplatin-resistant lung cancer cells by downregulating MRP2 and LRP expression

Cisplatin resistance is a main clinical problem of lung cancer therapy. Gambogic acid (GA) could prohibit the proliferation of a variety of human cancer cells. However, the effects of GA on cisplatin-resistant lung cancer are still unclear. The objective of the present study was to find out the antitumor effects of GA on cisplatin-resistant human lung cancer A549/DDP cells and further explore its underlying mechanisms. Cell Counting Kit-8 assay was used to observe the impacts of GA and/or cisplatin on the proliferation of lung cancer cells; flow cytometry was used to detect the effects of GA on cell cycle and apoptosis; Western blot was used to examine the effects of GA on the expression of lung resistance protein (LRP) and multidrug resistance-associated protein 2 (MRP2) protein in A549/DDP cells. Our results showed that GA dose- and time-dependently prohibited the proliferation and induced significant cell apoptosis in A549 and A549/DDP cells. GA also induced G0/G1 arrest in both A549/DDP and A549 cells. Moreover, GA upregulated protein expression level of cleaved caspase-3 and Bax and downregulated protein expression level of pro-caspase-9 and Bcl-2 in time- and dose-dependent way in A549/DDP cells. GA combined with cisplatin enhanced the cells apoptotic rate and reduced the cisplatin resistance index in A549/DDP cells. In addition, GA reduced the MRP2 and LRP protein expression level in A549/DDP cells. GA inhibits the proliferation, induces cell cycle arrest and apoptosis in A549/DDP cells. Combination of GA with cisplatin enhances the antitumor effects on cisplatin-resistant lung cancer cells by downregulating MRP2 and LRP expression.