Optimizing perioperative treatment for potentially resectable stage III squamous cell lung carcinoma: promising results of a condensed four-cycle regimen with tislelizumaband chemotherapy.

BACKGROUND: The standard care for resectable non-small cell lung cancer (NSCLC) involves perioperative therapy combining chemotherapy and immune checkpoint inhibitors, typically lasting 6 to 12 months. However, the optimal treatment strategies for potentially resectable squamous cell lung carcinoma (SCC) remain unclear. This Phase 2 trial aimed to assess the efficacy and safety of a condensed four-cycle perioperative treatment regimen with tislelizumab combined with chemotherapy in patients with potentially resectable stage III SCC. METHODS: Patients with potentially resectable stage IIIA-IIIB (N2) SCC received intravenous tislelizumab, albumin-bound paclitaxel, and carboplatin for up to four cycles. The primary endpoints were major pathologic response (MPR) and incidence of treatment-related adverse events. Safety and potential biomarkers for efficacy prediction were also assessed. RESULTS: Among 35 enrolled patients, 32 underwent surgery with R0 resection achieved in all cases. MPR was achieved in 24 patients and pathological complete response (pCR) in 14 patients. Radiographic objective response was observed in 31 patients. The 12-month and 24-month event-free survival rate was 85.7 and 61.0%, respectively. Four patients experienced grade 3 or 4 adverse events. Tumor tissue based next-generation sequencing revealed the potential associations between several biomarkers and pathological response, including tumor neoantigen burden score, 18-gene expression profile score, CD8 + T cells, M1/M2 macrophages ratio and interferon-gamma expression level. Besides, circulating tumor DNA (ctDNA) dynamics and concentration were also associated with pathological response and the presence of ctDNA at postoperative month 1 was a strong predictor for disease relapse. Furthermore, metagenomic sequencing in bronchoalveolar lavage fluid demonstrated Streptococcus was the most abundant genus in the pCR group. CONCLUSIONS: A condensed four-cycle perioperative treatment regimen of tislelizumab combined with chemotherapy demonstrated promising efficacy and manageable toxicities in potentially resectable stage III SCC. Specific biomarkers showed potential for predicting treatment efficacy and the mechanism of superior antitumor response of pCR patients was preliminarily and indirectly explored. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05024266. Registered August 27, 2021.

Decreased expression of H19/miR-675 ameliorates hypoxia-induced oxaliplatin resistance in colorectal cancer.

Hypoxic microenvironment, a hallmark of solid tumors, contributes to chemoresistance, and long noncoding (lnc) RNAs are involved in hypoxia-induced drug resistance. However, the role of lncRNAs in hypoxic tumor chemotherapy resistance remains unclear. Here, we aimed to elucidate the effects of lncRNAs in hypoxia-mediated resistance in colorectal cancer (CRC), as well as the underlying mechanisms. The results indicated that the expression of lncRNA H19 was enhanced in hypoxia- or oxaliplatin-treated CRC cells; moreover, H19 contributed to drug resistance in CRC cells both in vitro and in vivo. Mechanistically, H19 was noted to act as a competitive endogenous RNA of miR-675-3p to regulate epithelial-mesenchymal transition (EMT). Notably, an miR-675-3p mimic could attenuate the effects of H19 deficiency in CRC cells with hypoxia-induced chemoresistance. In conclusion, H19 downregulation may counteract hypoxia-induced chemoresistance by sponging miR-675-3p to regulate EMT; as such, the H19/miR-675-3p axis might be a promising therapeutic target for drug resistance in CRC.

Neoadjuvant Camrelizumab for Non-Small Cell Lung Cancer: A Retrospective Multicenter, Real-World Study (CTONG2004).

BACKGROUND: Camrelizumab has shown encouraging efficacy in advanced non-small cell lung cancer (NSCLC), either as monotherapy or combined with chemotherapy. However, evidence of neoadjuvant camrelizumab for NSCLC remains lacking. METHODS: Patients with NSCLC treated with neoadjuvant camrelizumab-based therapy followed by surgery between December 2020 and September 2021 were retrospectively reviewed. Demographic and clinical data, details of neoadjuvant therapy and surgical information were retrieved. RESULTS: In this multicenter retrospective real-world study, 96 patients were included. Ninety-five patients (99.0%) received neoadjuvant camrelizumab combined with platinum-based chemotherapy, with a median of 2 cycles (range 1-6). The median interval from the last dose to surgery was 33 days (range 13-102 days). Seventy patients (72.9%) underwent minimally invasive surgery. Lobectomy was the most frequent surgical procedure (94 [97.9%]). The median estimated intraoperative blood loss was 100 mL (range 5-1200 mL), and the median operative time was 3.0 h (range 1.5-6.5 h). The R0 resection rate was 93.8%. Twenty-one patients (21.9%) experienced postoperative complications, with the most common being cough and pain (both 6 [6.3%]). The overall response rate was 77.1% (95% CI 67.4-85.0%), and the disease control rate was 93.8% (95% CI 86.9-97.7%). Twenty-six patients (27.1%, 95% CI 18.5-37.1%) had pathological complete response. Neoadjuvant treatment-related adverse events of grade ≥ 3 were reported in seven patients (7.3%), with the most frequent being abnormal liver enzymes (two [2.1%]). No treatment-related deaths were reported. CONCLUSION: The real-world data indicated that camrelizumab-based therapy had promising efficacy for NSCLC in the neoadjuvant setting, with manageable toxicities. Prospective studies investigating neoadjuvant camrelizumab are warranted.

Effectiveness and safety of camrelizumab in inoperable or advanced non-small cell lung cancer patients: a multicenter real-world retrospective observational study (CTONG2004-ADV).

Background: Camrelizumab plus chemotherapy have been approved as standards for the treatment of advanced non-small cell lung cancer (NSCLC) patients based on two phase III trials. However, clinical trial results may not be representative of the general population, as clinical trials often have specific inclusion and exclusion criteria. Our research aims to investigate the real-world effectiveness and safety of camrelizumab in inoperable or advanced NSCLC patients. Methods: This multicenter retrospective observational study included inoperable or advanced pathologically confirmed NSCLC patients who received at least one dose of camrelizumab at 22 hospitals. Clinical and follow-up data of camrelizumab were collected retrospectively from the medical records. The primary outcome was the objective response rate (ORR) and secondary outcomes were disease control rate (DCR), 6-month progression-free survival (PFS), overall survival (OS), and treatment-related adverse events (TRAEs). Multivariate logistic and Cox regression analyses were applied to identify potential predictive factors of ORR and PFS, respectively. Results: Between July 2019 and March 2021, 336 patients were included. Adenocarcinoma was seen in 58.4% and stage IV disease in 69.3%. Twenty-nine (8.6%) had liver metastasis at baseline. Most patients received camrelizumab in the first-line setting (74.1%) and in combination with chemotherapy (60.7%). The ORR was 40.2% [95% confidence interval (CI): 34.9-45.6%] and DCR was 85.1% (95% CI: 81.3-88.9%), while the 6-month PFS and OS rates were 73.0% (95% CI: 67.1-78.0%) and 93.1% (95% CI: 89.8-95.4%), respectively. In multivariate analyses, liver metastasis [odds ratio (OR), 0.324; 95% CI: 0.115-0.915; P=0.033] and increasing lines of camrelizumab treatment (vs. first line, second line: OR, 0.347; 95% CI: 0.162-0.741; P=0.006; ≥ third line: OR, 0.126; 95% CI: 0.043-0.367; P<0.001) were negatively associated, while a longer duration of camrelizumab treatment was positively associated with ORR and PFS. TRAEs were recorded in 164 (48.8%) patients, without new safety signal. Conclusions: We conducted a comprehensive overview of the effectiveness and safety profile of camrelizumab in a broader NSCLC population in real world NSCLC patients, and subgroup analysis indicated the presence of liver metastasis was associated with worse outcomes.

Radical Resection Combined With Intestinal Autotransplantation for Locally Advanced Pancreatic Cancer After Neoadjuvant Therapy: A Report of 36 Consecutive Cases.

OBJECTIVE: To achieve radical resection of locally advanced pancreatic ductal adenocarcinoma (PDAC), and tested the safety and benefits of intestinal autotransplantation in pancreatic surgery. BACKGROUND: PDAC has an extremely dismal prognosis. Radical resection was proved to improve the prognosis of patients with PDAC; however, the locally advanced disease had a very low resection rate currently. We explored and evaluated whether the combination of modern advances in systemic treatment and this macroinvasive surgery was feasible in clinical practice. METHODS: Patients diagnosed as PDAC with superior mesenteric artery involvement and with or without celiac trunk involvement were included. Patients were treated with modified-FOLFIRINOX chemotherapy with or without anti-PD-1 antibodies and were applied to tumor resection combined with intestinal autotransplantation. Data on operative parameters, pathologic results, mortality, morbidity, and survival were analyzed. RESULTS: A total of 36 consecutive cases were applied to this strategy and underwent radical resection combined with intestinal autotransplantation. Among these patients, 24 of them received the Whipple procedure, 11 patients received total pancreatectomy, and the other 1 patient received distal pancreatectomy. The median operation time was 539 minutes. Postoperative pathology showed an R0 resection rate of 94.4%, and tumor invasion of a superior mesenteric artery or superior mesenteric vein was confirmed in 32 patients. The median number of dissected lymph nodes was 43, and 25 patients were positive for lymph node metastasis. The median time of intensive care unit stay was 4 days. Two patients died within 30 days after surgery due to multiorgan failure. The severe postoperative adverse events (equal to or higher than grade 3) were observed in 12 out of 36 patients, and diarrhea, gastroparesis, and abdominal infection were the most frequent adverse events. Postoperative hospital stay was averagely of 34 days. The recurrence-free survival is 13.6 months. The median overall survival of patients after diagnosis and after surgery was 21.4 months and 14.5 months, respectively. CONCLUSIONS: Our attempt suggests the safety of this modality and may be clinically beneficial for highly selected patients with PDAC. However, the experience in multidisciplinary pancreatic cancer care and intestinal transplantation is warranted.

HOTAIR/miR-1277-5p/ZEB1 axis mediates hypoxia-induced oxaliplatin resistance via regulating epithelial-mesenchymal transition in colorectal cancer.

The hypoxic microenvironment contributes to the chemoresistance of many malignant tumors including colorectal cancer (CRC). Accumulating studies have indicated that long non-coding RNAs (lncRNAs) play important roles in chemotherapy resistance. In this study, we aimed to determine the effect of lncRNAs in hypoxia-mediated resistance in CRC and its potential mechanism. Here, we discovered that hypoxia-induced oxaliplatin resistance and HOX transcript antisense RNA (HOTAIR) expression was increased in hypoxia-treated CRC cell lines and CRC tumors. Knockdown of HOTAIR by siRNA reduced the viability and proliferation of CRC cells treated with oxaliplatin and reversed hypoxia-induced resistance. Mechanically, we found that HOTAIR modulates zinc finger E-box binding homeobox 1 (ZEB1) expression by negative regulations of miR-1277-5p. When miR-1277-5p was silenced, knockdown of HOTAIR was unable to reduce the oxaliplatin resistance in CRC cells. In mouse models of CRC, HOTAIR knockdown markedly inhibited the tumor growth when treated with oxaliplatin. Thus, HOTAIR/miR-1277-5p/ZEB1 axis appears a promising therapeutic target for improving the oxaliplatin efficacy in CRC.

Nanocarrier-Based Tumor-Targeting Drug Delivery Systems for Hepatocellular Carcinoma Treatments: Enhanced Therapeutic Efficacy and Reduced Drug Toxicity.

Hepatocellular carcinoma (HCC), due to the lack of efficient diagnostic methods and short of available treatments, becomes the third main cause of cancer deaths. Novel treatments for HCCs are thus in great need. The fast-growing area of drug delivery provides intriguing possibility to design nanocarriers with unique properties. The nanocarriers performanced as drug deliver vehicles enable the design of diverse drug delivery systems, which could serve multiple purposes, including improved bioavailability, controlled or triggered release and targeted delivery, leading to enhanced drug efficacy and lowered drug toxicity. This paper provides an overview on the types of delivery vehicles, functions of drug nanocarriers and types of ligand-based targeting systems and highlights the advances made towards better HCC treatments.

The emerging role of ubiquitin-specific protease 20 in tumorigenesis and cancer therapeutics.

As a critical member of the ubiquitin-specific proteolytic enzyme family, ubiquitin-specific peptidase 20 (USP20) regulates the stability of proteins via multiple signaling pathways. In addition, USP20 upregulation is associated with various cellular biological processes, such as cell cycle progression, proliferation, migration, and invasion. Emerging studies have revealed the pivotal role of USP20 in the tumorigenesis of various cancer types, such as breast cancer, colon cancer, lung cancer, gastric cancer and adult T cell leukemia. In our review, we highlight the different mechanisms of USP20 in various tumor types and demonstrate that USP20 regulates the stability of multiple proteins. Therefore, regulating the activity of USP20 is a novel tumor treatment. However, the clinical significance of USP20 in cancer treatment merits more evidence. Finally, different prospects exist for the continued research focus of USP20.

Prognostic Value of Lymph Node Evaluation in Stage II Small Bowel Adenocarcinoma: An Updated Analysis of Surveillance, Epidemiology, and End Results Database.

Background: Due to the lack of large-scale clinical trials, the treatment strategies of small bowel adenocarcinoma (SBA) are controversial, especially for stage II patients. According to the National Comprehensive Cancer Network (NCCN) guideline, few lymph nodes (LNs) examined (<5 for duodenum or <8 for jejunal/ileal primary location) are one of the high-risk features for stage II patients, for whom adjuvant chemotherapy is recommended. This consensus is originally drawn from data in the Surveillance, Epidemiology, and End Results Database (SEER) between 1988 and 2010. However, the surgical modalities and chemotherapy strategies changed a lot after 2004 for SBA patients. The previous data may not represent a true picture of current therapeutics. Thus, we reanalyzed the SEER database and updated the cutoff point of LN numbers resected with respect to cancer-specific survival (CSS) using the latest SEER information. Methods: Patients diagnosed with stage II SBA and who underwent curative surgery between 2004 and 2018 were extracted from the SEER database. CSS was calculated using the Kaplan-Meier method and compared by log-rank test. Maximum survival differences based on total LNs examined for duodenal and jejunoileal tumors were determined separately with the cut-point analysis and maximum log-rank χ2 statistic. A nomogram model was constructed based on the multivariate Cox analysis to predict 5- and 10-year CSS and was then validated with an internal cohort. Results: A total of 935 stage II SBA patients met the inclusion criteria. The greatest difference in survival was found in patients who had removal of at least 5 LNs for duodenal and 12 LNs for jejunoileal tumors. Multivariate Cox analysis showed that age, T stage, histology grade, primary site, and LN numbers were independent prognostic factors for survival. The C index of nomogram model was 0.701 (95% CI, 0.661-0.741, p < 0.001). Conclusions: The number of LNs harvested is an important prognostic factor for survival in stage II SBA patients. LN number examined <5 remains a high-risk factor for duodenum, but the cutoff point for jejunal/ileal tumors should rise from 8 to 12. Appropriate radical lymphadenectomy should be performed in stage II SBA surgery.

Label-Free Sensing of Cysteine through Cadmium Ion Coordination: Smartphone-Based Electrochemical Detection.

The detection of biologically important compounds such as cysteine remains a challenge for monitoring body metabolism. This work proposes a transition metal ion coordination-based label-free cysteine sensor with smartphone-based square wave voltammetry sensing system for the point-of-care testing (POCT). In the sensing system, potential excitation and current measurements were accomplished by a miniaturized and integrated circuit board with a smartphone to wirelessly control the system via Bluetooth. The electrochemical currents changed with the cysteine concentrations ranging from 0 µM to 200 µM with a linearity correlation coefficient of 0.9915. The limit of detection was as low as 0.0149 µM for cysteine. The smartphone-based system provides an effective strategy for cysteine detection, and it can also serve as a promising portable sensing platform for the analysis of other small molecules.

Reducing Acneiform Rash Induced by EGFR Inhibitors With Honeysuckle Therapy: A Prospective, Randomized, Controlled Study.

Background: Epidermal growth factor receptor inhibitors (EGFRIs), including cetuximab, erlotinib, gefitinib and icotinib, have been proven to be effective in treating colorectal cancer or lung cancer. However, most of patients who receive EGFRIs treatment experience cutaneous toxicities, such as acneiform or papulopustular rashes, which affects quality of life and leads to discontinuation of cancer therapies. Honeysuckle is a traditional herb historically used to treat skin rash for thousands of years in Eastern Asia and showed proven safety in human. Methods: To investigate whether honeysuckle therapy could control EGFRIs induced acneiform rashes, a total of 139 colorectal and lung cancer patients with EGFRIs treatments were recruited in a prospective study. Patients were randomized to 3 arms (Arm A: prophylactic treatment with honeysuckle before rash occurred; Arm B: symptomatic treatment with honeysuckle when rash occurred; Arm C: conventional treatment with minocycline and a topical solution when rash occurred). The incidences, severities and recovery time of acneiform rash were observed in each arm. Results: Honeysuckle treatment reduced incidences of EGFRIs induced acneiform rash, which were 56.5, 68.1 and 71.7% in Arm A, B and C, respectively (p = 0.280). Severities of rash (CTCAE grade 2 and 3) were significantly lower in prophylactic honeysuckle treatment (Arm A) compared to conventional treatment (Arm C) (p = 0.027), which was 10-21%, respectively. Patients with honeysuckle treatment recovered more quickly from pruritus, the median time was 22, 36 and 58 days in Arm A, B and C, respectively (p = 0.016). Conclusion: Honeysuckle was effective in reducing incidences and severities of EGFRIs induced acneiform rash, especially for prophylactic treatment.

Modulation of the tumour microenvironment in hepatocellular carcinoma by tyrosine kinase inhibitors: from modulation to combination therapy targeting the microenvironment.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Tyrosine kinase inhibitors (TKIs) remain the backbone of systematic therapy for advanced hepatocellular carcinoma. Sorafenib and lenvatinib are currently approved as first-line therapeutic drugs, and regorafenib and cabozantinib are applied as second-line treatments. With inhibition of angiogenesis as the main target, TKIs exert a profound effect on the tumour microenvironment (TME). The TME is a complex mixture of cellular and noncellular components surrounding the tumour mass, and is associated with tumour progression partially through the epithelial-mesenchymal transition. Specifically, the TME of HCC is characterized by profound extracellular matrix remodelling and an immunosuppressive microenvironment. The purpose of this review is to provide a summary of TME remodelling mediated by four Food and Drug Administration approved TKIs in HCC and thus summarize the rationale and potential targets for combination therapy. The modulatory effect of TKIs on the TME of HCC was reported to enhance the antitumour effect of TKIs through pyroptosis of macrophages and subsequent natural killer cell activation, T cell activation, regulatory T cell reduction in HCC. Meanwhile, TKIs also induce drug resistance via M2 polarization and accumulation, recruitment of tumour-associated neutrophils, and induction of the epithelial-mesenchymal transition. In conclusion, the effect of TKIs on TME can enhance its antitumour effect, but might also partially contribute to the drug resistance that hinders the progression of TKIs as treatment for HCC. Additionally, the effect of TKIs also provides the rationale for combination therapy, including combining TKIs with immune checkpoint inhibitors, to facilitate increased drug efficacy of TKIs.

Chinese Expert Consensus on Immunotherapy for Hepatocellular Carcinoma (2021 Edition).

Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies in China. Most HCC patients are first diagnosed at an advanced stage, and systemic treatments are the mainstay of treatment. Summary: In recent years, immune checkpoint inhibitors have made a breakthrough in the systemic treatment of middle-advanced HCC, breaking the single therapeutic pattern of molecular-targeted agents. To better guide the clinical treatment for effective and safe use of immunotherapeutic drugs, the Chinese Association of Liver Cancer and Chinese Medical Doctor Association has gathered multidisciplinary experts and scholars in relevant fields to formulate the "Chinese Clinical Expert Consensus on Immunotherapy for Hepatocellular Carcinoma (2021)" based on current clinical studies and clinical medication experience for reference in China. Key Messages: The consensus contained 17 recommendations, including the preferred regimen for first- and second-line immunotherapy, evaluation and monitoring before/during/after treatment, management of complications, precautions for special patients, and potential population for immunotherapy.

BRAF Mutation as a Potential Therapeutic Target for Checkpoint Inhibitors: A Comprehensive Analysis of Immune Microenvironment in BRAF Mutated Colon Cancer.

BRAF mutated colon cancer presents with poor survival, and the treatment strategies are controversial. The tumor microenvironment, which plays a key role in tumorigenesis as well as responses to treatments, of this subtype is largely unknown. In the present study, we analyzed the differences of immune microenvironments between BRAF mutated and BRAF wild-type colon cancer utilizing datasets from The Cancer Genome Atlas and Gene Expression Omnibus and confirmed the findings by tissue specimens of patients. We found that BRAF mutated colon cancer had more stromal cells, more immune cell infiltration, and lower tumor purity. Many immunotherapeutic targets, including PD-1, PD-L1, CTLA-4, LAG-3, and TIM-3, were highly expressed in BRAF mutated patients. BRAF mutation was also correlated with higher proportions of neutrophils and macrophages M1, and lower proportions of plasma cells, dendritic cells resting, and T cells CD4 naïve. In conclusion, our study demonstrates a different pattern of the immune microenvironment in BRAF mutated colon cancer and provides insights into the future use of checkpoint inhibitors in this subgroup of patients.

Efficacy of Pyrotinib in a Heavily Pretreated Patient with Lung Adenocarcinoma Harboring HER2 Amplification and Exon 20 Insertions: A Case Report.

The clinical benefits of HER2 inhibitors in patients with non-small cell lung cancer (NSCLC) have been limited. There is a paucity of effective therapies in NSCLC after developing resistance to initial anti-HER2 therapy. Herein, we presented the clinical benefit of pyrotinib in a 53-year-old patient with advanced lung adenocarcinoma whose circulating tumor DNA (ctDNA) analysis of pleural effusion revealed the coexistence of HER2 exon 20 p.Y772_A775dup (mutation ratio: 38.86%) and HER2 amplification (copy number: 4.5) following failures of multiple therapies including afatinib and ado-trastuzumab emtansine (T-DM1). Notably, pyrotinib treatment induced rapid and marked improvement of clinical symptoms, and partial response was observed after 8 weeks. CtDNA monitoring during the treatment showed that the mutation ratio of HER2 decreased to 7.99%, and the amplification disappeared. The patient achieved a progression-free survival of 7.5 months after treatment with pyrotinib. Thus, pyrotinib may be a new treatment strategy for the subgroup of lung adenocarcinoma patients, with coexistence of HER2 exon 20 p.Y772_A775dup and HER2 amplification even after failures of multiple anti-HER2 therapies. It also indicated the value of capture-based next-generation sequencing to monitor and guide therapy.

Concurrent Treatment with Anti-DLL4 Enhances Antitumor and Proapoptotic Efficacy of a γ-Secretase Inhibitor in Gastric Cancer.

The Notch signaling pathway has been identified as a therapeutic target for cancers. γ-Secretase inhibitors (GSIs) have been progressively recognized as potential anticancer drugs. The present study aimed to investigate the effects of anti-delta like legend 4 (anti-DLL4) treatment on the anticancer efficacy of GSIs in gastric cancer. SGC-7901-GFP human gastric cancer cells were tested for DLL4 expression by rosette formation test and immunofluorescence, and then were treated with anti-DLL4 antibody N-[N-(3,5-difluorophenacetyl)-L-ananyl]-S-phenylglycine t-butyl ester (DAPT, a type of GSI), or a combination of anti-DLL4 antibody and DAPT. The effects of in vitro treatments on cell apoptosis, cell cycle, and cell invasion were analyzed. For in vivo study, an orthotopic mouse model of gastric cancer was established with green fluorescence expressing SGC-7901. Ultrasound targeted microbubble destruction was used to treat tumor-bearing mice with anti-DLL4 antibody conjugated microbubbles, DAPT, and a combination of the two. Real-time fluorescence imaging was performed to assess tumor cell inhibition in each group. Following in vivo treatments, apoptosis of tumor cells and the expression of apoptosis-related genes BAX, Bcl-2, and P53 were detected by TUNEL and immunohistochemical staining. In vivo combined treatment of anti-DLL4 and DAPT led to a higher rate of cell apoptosis and greater inhibition of cell invasion than that observed with DAPT treatment alone. DAPT and anti-DLL4 combination therapy resulted in decreased cell distribution at G1 phase and increased cell distribution at S phase, compared to the untreated control group (P < .01). In vivo combined therapy with anti-DLL4 and DAPT significantly increased tumor growth inhibition and tumor cell apoptosis when compared to DAPT therapy alone (P < .05). In addition, combined treatment significantly increased expression of BAX and P53 and reduced Bcl-2 expression (P < .05). Conversely, treatment with DAPT alone only increased expression of BAX and P53 (P < .05), suggesting that the reduction of Bcl-2 expression may play an important role in the synergetic antitumor and proapoptosis effects of the combined treatment. Concurrent treatment with anti-DLL4 enhances the antitumor and proapoptotic efficacy of the γ-secretase inhibitor in gastric cancer both in vitro and in vivo.

Ursolic acid sensitized colon cancer cells to chemotherapy under hypoxia by inhibiting MDR1 through HIF-1α.

OBJECTIVE: To explore the efficacy of ursolic acid in sensitizing colon cancer cells to chemotherapy under hypoxia and its underlying mechanisms. METHODS: Three colon cancer cell lines (RKO, LoVo, and SW480) were used as in vitro models. 5-Fluorouracil (5-FU) and oxaliplatin were used as chemotherapeutic drugs. Cell viability and apoptosis were tested to evaluate the sensitivity of colon cancer cells to chemotherapy. The transcription and expression levels of hypoxia-inducible factor-1α (HIF-1α), multidrug resistance gene 1 (MDR1), and vascular endothelial growth factors (VEGF) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunoblotting. Cycloheximide and MG132 were used to inhibit protein synthesis and degradation, respectively. In vitro tube formation assay was used to evaluate angiogenesis. RESULTS: We demonstrated the chemosensitizing effects of ursolic acid with 5-FU and oxaliplatin in three colon cancer cell lines under hypoxia. This effect was correlated to its inhibition of MDR1 through HIF-1α. Moreover, ursolic acid was capable of inhibiting HIF-1α accumulation with little effects on its constitutional expression in normoxia. In addition, ursolic acid also down-regulated VEGF and inhibited tumor angiogenesis. CONCLUSIONS: Ursolic acid exerted chemosensitizing effects in colon cancer cells under hypoxia by inhibiting HIF-1α accumulation and the subsequent expression of the MDR1 and VEGF.

Ursolic acid synergistically enhances the therapeutic effects of oxaliplatin in colorectal cancer.

Oxaliplatin is a key drug in chemotherapy of colorectal cancer (CRC). However, its efficacy is unsatisfied due to drug resistance of cancer cells. In this study, we tested whether a natural agent, ursolic acid, was able to enhance the efficacy of oxaliplatin for CRC. Four CRC cell lines including SW480, SW620, LoVo, and RKO were used as in vitro models, and a SW620 xenograft mouse model was used in further in vivo study. We found that ursolic acid inhibited proliferation and induced apoptosis of all four cells and enhanced the cytotoxicity of oxaliplatin. This effect was associated with down-regulation of Bcl-xL, Bcl-2, survivin, activation of caspase-3, 8, 9, and inhibition of KRAS expression and BRAF, MEK1/2, ERK1/2, p-38, JNK, AKT, IKKα, IκBα, and p65 phosphorylation of the MAPK, PI3K/AKT, and NF-κB signaling pathways. The two agents also showed synergistic effects against tumor growth in vivo. In addition, ursolic acid restored liver function and body weight of the mice treated with oxaliplatin. Thus, we concluded that ursolic acid could enhance the therapeutic effects of oxaliplatin against CRC both in vitro and in vivo, which offers an effective strategy to minimize the burden of oxaliplatin-induced adverse events and provides the groundwork for a new clinical strategy to treat CRC.

Non-enzymatic action of RRM1 protein upregulates PTEN leading to inhibition of colorectal cancer metastasis.

Ribonucleotide reductase large subunit M1 (RRM1) forms a holoenzyme with small subunits to provide deoxyribonucleotides for DNA synthesis and cell proliferation. Here, we reported a non-RR role of the catalytic subunit protein RRM1 and related pathway in inhibiting colorectal cancer (CRC) metastasis. Ectopic overexpression of the wild-type RRM1, and importantly, its Y738F mutant that lacks RR enzymatic activity, prevented the migration and invasion of CRC cells by promoting phosphatase and tensin homolog on chromosome 10 (PTEN) transactivation. Furthermore, overexpression of the wild-type and RR-inactive mutant RRM1 similarly reduced the phosphorylation of Akt and increased the E-cadherin expression in CRC cells, which were blocked by PTEN knockdown attenuation. Examination of clinical CRC specimens demonstrated that both RRM1 protein expression and RR activity were elevated in most cancer tissues compared to the paired normal tissues. However, while RR activity did not change significantly in different cancer stages, the RRM1 protein level was significantly increased at stages T1-3 but decreased at stage T4, in parallel with the PTEN expression level and negatively correlated with invasion and liver metastasis. Thus, we propose that RRM1 protein can inhibit CRC invasion and metastasis at the advanced stage by regulating PTEN transactivation and its downstream pathways in addition to forming an RR holoenzyme for supporting cancer proliferation. Understanding of the seemingly contrary dual roles of RRM1 protein may further help to explain the complex mechanisms by which this key enzyme and its components are involved in cancer development.

Interferon regulatory factor 1 transactivates expression of human DNA polymerase η in response to carcinogen N-methyl-N'-nitro-N-nitrosoguanidine.

DNA polymerase η (Polη) implements translesion DNA synthesis but has low fidelity in replication. We have previously shown that Polη plays an important role in the genesis of nontargeted mutations at undamaged DNA sites in cells exposed to the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Here, we report that MNNG-induced Polη expression in an interferon regulatory factor 1 (IRF1)-dependent manner in human cells. Mutagenesis analysis showed that four critical residues (Arg-82, Cys-83, Asn-86, and Ser-87) located in the IRF family conserved DNA binding domain-helix α3 were involved in DNA binding and POLH transactivation by IRF1. Furthermore, Polη up-regulation induced by IRF1 was responsible for the increase of mutation frequency in a SupF shuttle plasmid replicated in the MNNG-exposed cells. Interestingly, IRF1 was acetylated by the histone acetyltransferase CBP in these cells. Lys → Arg substitution revealed that Lys-78 of helix α3 was the major acetylation site, and the IRF1-K78R mutation partially inhibited DNA binding and its transcriptional activity. Thus, we propose that IRF1 activation is responsible for MNNG-induced Polη up-regulation, which contributes to mutagenesis and ultimately carcinogenesis in cells.