A phase II study of raltitrexed and gemcitabine in patients with advanced pancreatic carcinoma

A comparison between raltitrexed plus cisplatin and docetaxel plus cisplatin in concurrent chemoradiation for non-surgical esophageal squamous cell carcinoma

PURPOSE

Chemoradiotherapy (CRT) is considered as a standard treatment for unresectable and inoperable esophageal cancer (EC) patients. However, no consensus has been reached regarding the optimal synchronous chemotherapy regimen and the best combination of radiotherapy and chemotherapy. The aim of this study was to evaluate the efficacy and toxicity of raltitrexed plus cisplatin and docetaxel plus cisplatin to find a safe and effective concurrent chemotherapy schedule.

PATIENTS AND METHODS

Our retrospective study included 151 EC patients treated with raltitrexed and cisplatin (RP) (n=90) or docetaxel and cisplatin (DP) (n=61) from 2011 till 2018. Survival outcomes and treatment related toxicity were analyzed between the two groups.

RESULTS

PFS and OS were 18 and 34 months in the RP group, while 13 and 20 months in the DP group (P=0.118 and P=0.270). The 1-, 2-, 3-year survival rates of the RP group were 71.1, 55.4 and 46.4%. For the DP group, these were 63.9, 44.3 and 37.6%, respectively. Compared with DP group, RP group received a superior CR rate (68.9% versus 52.5%, P=0.041). There was a trend that the total number of toxic reactions in RP group was lower than that in DP group (P=0.058).

CONCLUSIONS

Even RP and DP groups have the similar survival outcomes and toxicity, raltitrexed/cisplatin get a higher complete response rate. Our study suggests that raltitrexed combined with cisplatin is a safe and effective concurrent chemotherapy regimen and it might be used as an alternative for cisplatin/5-FU and cisplatin/docetaxel in CCRT for EC patients.

Emodin alleviates gemcitabine resistance in pancreatic cancer by inhibiting MDR1/P-glycoprotein and MRPs expression

Gemcitabine is a gold standard chemotherapeutic agent for pancreatic cancer. However, gemcitabine has limited effectiveness due to the short-term development of chemoresistance. Emodin, a natural anthraquinone derivative isolated from the roots of rheumatic palm leaves prevents immunosuppression and exerts anticancer effects. The present study aimed to evaluate the effect of emodin on gemcitabine resistance. Gemcitabine-resistant PANC-1 pancreatic cancer cell xenografts were established in athymic mice, which were randomly assigned into four treatments groups as follows: Gemcitabine group, Emodin group, Gemcitabine+Emodin group and Negative control group. Body weight, tumor volume and tumor weight were measured over the course of treatment. The effect of each treatment on tumor tissue proliferation and apoptosis from nude mice was evaluated by using immunohistochemistry. The effect of each treatment on the proliferation of gemcitabine-resistant PANC-1 cells was also determined by using the Cell Counting Kit-8. Then, reverse transcription-quantitative (RT-q) PCR and western blotting were used to detect the mRNA and protein expression, respectively, of multidrug resistance gene 1 (MDR1) and the drug resistance-related proteins MRP1 and MRP5. The function and expression level of DR1 gene product, p-glycoprotein, was also analysed by flow cytometry and RT-qPCR, respectively. The results demonstrated that the combination of gemcitabine and emodin significantly reduced xenograft volume and reduced tumor growth in mice compared with treatment with gemcitabine or emodin only. In addition, emodin treatment reduced resistance to gemcitabine, which was characterized by the downregulation of P-glycoprotein, MRP1 and MRP5 expression in the group receiving combination treatment. The level of P-glycoprotein was also decreased in the group treated with gemcitabine+emodin compared with the single treatment groups. Taken together, these results demonstrated that emodin enhanced gemcitabine efficacy in tumor treatment and alleviated gemcitabine resistance in PANC-1 cell xenografts in mice via suppressing MDR1/P-glycoprotein and MRP expression.

Suppression of IL-6 Gene by shRNA Augments Gemcitabine Chemosensitization in Pancreatic Adenocarcinoma Cells

Pancreatic adenocarcinoma has an exceedingly poor prognosis, accounting for five-year survival of less than 5%. Presently, improving the efficacy of pancreatic adenocarcinoma treatment has been the focus of medical researchers worldwide. Recently, it has been suggested that deregulation of interleukin- (IL-) 6 is caused by a key gene involved in the beginning and development of pancreatic adenocarcinoma. Herein, we investigated whether suppression of IL-6 could augment gemcitabine sensitivity in the PANC-1 cells. We found considerably higher expression of IL-6 in pancreatic adenocarcinoma tissues than that in the adjacent nontumorous tissues. Suppression of IL-6 by shRNA resulted in apoptosis as well as inhibition of cell proliferation and tumorigenicity. In addition, suppression of IL-6 remarkably promoted antitumor effect of gemcitabine, indicating that the combination of shRNA targeting IL-6 with gemcitabine may provide a potential clinical approach for pancreatic cancer therapy.

Shikonin induces apoptosis and necroptosis in pancreatic cancer via regulating the expression of RIP1/RIP3 and synergizes the activity of gemcitabine

Pancreatic cancer is a lethal solid malignancy with poor prognosis. The optimal therapy for patients with advanced pancreatic cancer remains challenged. Thus, development of novel chemotherapy regimens is extremely urgent. Shikonin (SK) is a naphthoquinone derived from the roots of the Chinese medicinal herb Lithospermum erythrorhizon. It has been considered as effective anti-inflammatory, anti-oxidant, and anti-cancer activity agents in various diseases. In the present study, we found that SK inhibited the growth of human pancreatic cancer and enhanced the anti-tumor effect of gemcitabine in vitro and in vivo. Moreover, SK induced apoptosis and necroptosis in different pancreatic cancer cells by regulating RIP1 and RIP3 expression. The expression of RIP3 correlated with their necrotic response. These results suggest that the combination of SK and gemcitabine may be a promising chemotherapy regimen for pancreatic cancer.

WNT5A modulates cell cycle progression and contributes to the chemoresistance in pancreatic cancer cells

BACKGROUND

Although there are many studies on the mechanism of chemoresistance in cancers, studies on the relations between WNT5A and chemoresistance in pancreatic cancer are rare. The present study was to examine the role of WNT5A in the regulation of cell cycle progression and in chemo-resistance in pancreatic cancer tissues and cell lines.

METHODS

Fresh pancreatic cancer and paracarcinoma tissues were obtained from 32 patients. The expressions of WNT5A, AKT/p-AKT and Cyclin D1 were detected by immunohistochemistry, and the correlation between WNT5A expression and clinicopathological characteristics was analyzed. The relationship between WNT5A expression and gemcitabine resistance was studied in PANC-1 and MIAPaCa2 cell lines. The effect of WNT5A on the regulation of cell cycle and gemcitabine cytotoxicity were investigated. The associations among the expressions of p-AKT, Cyclin D1 and WNT5A were also analyzed in cell lines and the effect of WNT5A on restriction-point (R-point) progression was evaluated.

RESULTS

WNT5A, p-AKT and Cyclin D1 were highly expressed in pancreatic cancer tissues, and the WNT5A expression was correlated with the TNM stages. In vitro, WNT5A expression was associated with gemcitabine chemoresistance. The percentage of cells was increased in G0/G1 phase and decreased in S phase after knockdown of WNT5A in PANC-1. WNT5A promoted Cyclin D1 expression through phosphorylation of AKT which consequently enhanced G1-S transition and gemcitabine resistance. Furthermore, WNT5A enhanced the cell cycle progression toward R-point through regulation of retinoblastoma protein (pRb) and pRb-E2F complex formation.

CONCLUSIONS

WNT5A induced chemoresistance by regulation of G1-S transition in pancreatic cancer cells. WNT5A might serve as a predictor of gemcitabine response and as a potential target for tumor chemotherapy.

Inhibitory effect of geraniol in combination with gemcitabine on proliferation of BXPC-3 human pancreatic cancer cells

Objective

To investigate the inhibitory effect of geraniol alone, or in combination with gemcitabine, on the proliferation of BXPC-3 pancreatic cancer cells.

Methods

BXPC-3 cells were treated under different conditions: with geraniol at 10, 20, 40, 80 and 160 µmol/l each for 24 h, 48 h or 72 h; with 20 µmol/l geraniol for 24 h or 0 h before 20 µmol/l gemcitabine for 24 h; with 20 µmol/l geraniol for 24 h, 48 h and 72 h following 20 µmol/l gemcitabine for 24 h; or with 20 µmol/l gemcitabine alone as a control. Cell proliferation was assessed and changes in cell morphology were assessed by light and fluorescence microscopy. Apoptosis was detected using flow cytometry.

Results

Geraniol inhibited BXPC-3 cell proliferation in a time- and dosa-dependent manner. Geraniol alone or combined with gemcitabine induced BXPC-3 cell apoptosis. BXPC-3 inhibition rates with combined treatment were 55.24%, 50.69%, 49.83%, 41.85% and 45.27% following treatment with 20 µmol/l geraniol for 24 h or 0 h before 20 µmol/l gemcitabine for 24 h, or 20 µmol/l geraniol for 24 h, 48 h and 72 h, following 20 µmol/l gemcitabine for 24 h, respectively.

Conclusion

Geraniol inhibited the proliferation of BXPC-3 cells. Geraniol significantly increased the antiproliferative and apoptosis-inducing effects of gemcitabine on BXPC-3 cells. Maximum inhibition of BXPC-3 cells was achieved with geraniol treatment for 24 h before gemcitabine treatment.

Involvement of the phosphoinositide 3-kinase/Akt pathway in apoptosis induced by capsaicin in the human pancreatic cancer cell line PANC-1

Capsaicin, one of the major pungent ingredients found in red peppers, has been recently demonstrated to induce apoptosis in various malignant cell lines through an unclear mechanism. In this study, the effect of capsaicin on proliferation and apoptosis in the human pancreatic cancer cell line PANC-1 and its possible mechanism(s) of action were investigated. The results of a Cell Counting Kit-8 (CCK-8) assay revealed that capsaicin significantly decreased the viability of PANC-1 cells in a dose-dependent manner. Capsaicin induced G0/G1 phase cell cycle arrest and apoptosis in PANC-1 cells as demonstrated by a flow cytometric assessment. Caspase-3 expression at both the protein and mRNA level was promoted following capsaicin treatment. Furthermore, we revealed that phospho-PI3 Kinase p85 (Tyr458) and phospho-Akt (Ser473) in PANC-1 cells were downregulated in response to capsaicin. Moreover, capsaicin gavage significantly inhibited the growth of pancreatic cancer PANC-1 cell xenografts in athymic nude mice. An increased number of TUNEL-positive cells and cleaved caspase-3 were observed in capsaicin-treated mice. In vivo, capsaicin downregulated the expression of phospho-PI3 Kinase p85 (Tyr458) and phospho-Akt (Ser473). In conclusion, we have demonstrated that capsaicin is an inhibitor of growth of PANC-1 cells, and downregulation of the phosphoinositide 3-kinase/Akt pathway may be involved in capsaicin-induced apoptosis in vitro and in vivo.

Molecular evidence for increased antitumor activity of gemcitabine in combination with a cyclin-dependent kinase inhibitor, P276-00 in pancreatic cancers

Background

P276-00 is a novel cyclin-dependent kinase inhibitor currently in Phase II clinical trials. Gemcitabine is a standard of care for the treatment of pancreatic cancer. The present study investigated the effect of the combination of P276-00 and gemcitabine in five pancreatic cancer cell lines.

Methods

Cytotoxic activity was evaluated by Propidium Iodide assay. Cell cycle and apoptosis was analyzed by flow cytometry. Genes and proteins known to inhibit apoptosis and contribute to chemoresistance were analysed using western blot analysis and RT-PCR. In vivo efficacy was studied in PANC-1 xenograft model.

Results

The combination of gemcitabine followed by P276-00 was found to be highly to weakly synergistic in various pancreatic cancer cell lines as assessed by the combination index. Enhancement of apoptosis in PANC-1 cells and decrease in the antiapoptotic protein Bcl-2 and survivin was seen. P276-00 potentiated the gemcitabine-induced cytotoxicity by modulation of proteins involved in chemoresistance to gemcitabine and cell cycle viz. antiapoptotic proteins p8 and cox-2, proapoptotic protein BNIP3 and cell cycle related proteins Cdk4 and cyclin D1. The above results could explain the novel mechanisms of action of the combination therapy. We also show here that gemcitabine in combination with P276-00 is much more effective as an antitumor agent compared with either agent alone in the PANC-1 xenograft tumor model in SCID mice.

Conclusions

The chemosensitzation of pancreatic tumors to gemcitabine would likely be an important and novel strategy for treatment of pancreatic cancer and enable the use of lower and safer concentrations, to pave the way for a more effective treatment in this devastating disease. Phase IIb clinical trials of P276-00 in combination with gemcitabine in pancreatic cancer patients are ongoing.

Dihydroartemisinin inactivates NF-kappaB and potentiates the anti-tumor effect of gemcitabine on pancreatic cancer both in vitro and in vivo

Gemcitabine is currently the best known chemotherapeutic option available for pancreatic cancer, but the tumor returns de novo with acquired resistance over time, which becomes a major issue for all gemcitabine-related chemotherapies. In this study, for the first time, we demonstrated that dihydroartemisinin (DHA) enhances gemcitabine-induced growth inhibition and apoptosis in both BxPC-3 and PANC-1 cell lines in vitro. The mechanism is at least partially due to DHA deactivates gemcitabine-induced NF-kappaB activation, so as to decrease tremendously the expression of its target gene products, such as c-myc, cyclin D1, Bcl-2, Bcl-xL. In our in vivo studies, gemcibabine also manifested remarkably enhanced anti-tumor effect when combined with DHA, as manifested by significantly increased apoptosis, as well as decreased Ki-67 index, NF-kappaB activity and its related gene products, and predictably, significantly reduced tumor volume. We concluded that inhibition of gemcitabine-induced NF-kappaB activation is one of the mechanisms that DHA dramatically promotes its anti-tumor effect on pancreatic cancer.

Enhanced anti-tumor effect of combination therapy with gemcitabine and apigenin in pancreatic cancer

Apigenin is a dietary flavonoid possessing therapeutic potential against cancers. This study was designed to investigate whether combination therapy with gemcitabine and apigenin enhanced anti-tumor efficacy in pancreatic cancer. In vitro, the combination treatment resulted in more growth inhibition and apoptosis through the down-regulation of NF-kappa B activity with suppression of Akt activation in pancreatic cancer cell lines (MiaPaca-2, AsPC-1). In vivo, the combination therapy augmented tumor growth inhibition through the down-regulation of NF-kappa B activity with the suppression of Akt in tumor tissue. The combination of gemcitabine and apigenin enhanced anti-tumor efficacy through Akt and NF-kappa B activity suppression and apoptosis induction.

Pancreatic cancer: a review of recent advances

Pancreatic cancer is one of the most common causes of cancer-related death. Despite the advances of the molecular pathogenesis, pancreatic cancer remains a major unsolved health problem. Overall, the 5-year survival rate is < 5% and only approximately 20% of the 10% of patients with resectable disease survive 5 years. Recently, the European Study Group for Pancreatic Cancer 1 trial demonstrated substantially increased survival from adjuvant chemotherapy with 5-fluorouracil-folinic acid and preliminary data showed prolonged disease-free survival from adjuvant gemcitabine. Current palliative therapeutic approaches mostly focused on evaluating chemotherapy regimens in which gemcitabine is combined with a second cytotoxic agent. Recently, large randomised trials of combinations of gemcitabine with either capecitabine or with erlotinib demonstrated prolonged survival and 1-year survival rates of approximately 25%. The advance of molecular biology has led to the elucidation of molecular events that are important for pancreatic carcinogenesis and has provided a foundation for the development of novel chemotherapeutic and biological agents that appear to be promising and are likely to play a future role in the treatment of patients with advanced pancreatic cancer.

Molecular evidence for increased antitumor activity of gemcitabine by genistein in vitro and in vivo using an orthotopic model of pancreatic cancer

Soy isoflavone genistein exhibits growth inhibitory activity against human pancreatic cancer cell lines. We previously reported the potential of genistein to augment chemotherapeutic response of pancreatic cancer cells in vitro. In the present study, we investigated whether genistein pretreatment could be used as a novel strategy for gemcitabine-induced killing in vitro and enhanced antitumor activity in vivo using an orthotopic tumor model. We conducted our studies using paired isogenic human pancreatic cancer cell line with differences in metastatic behavior (COLO 357 and L3.6pl). In vitro studies were done to measure growth inhibition and degree of apoptotic cell death induced by either genistein alone, gemcitabine alone, or genistein followed by gemcitabine. Our results show that pretreatment of cells with genistein for 24 hours followed by gemcitabine resulted in 60% to 80% growth inhibition compared with 25% to 30% when gemcitabine was used alone. The overall growth inhibition was directly correlated with apoptotic cell death irrespective of the metastatic potential of cells. Several genes that are known to inhibit apoptosis and contribute to chemoresistance such as nuclear factor-kappaB (NF-kappaB) and Akt were assessed to investigate the basis for the observed chemosensitizing effects of genistein. Genistein potentiated the gemcitabine-induced killing by down-regulation of NF-kappaB and Akt. In contrast, Akt and NF-kappaB were found to be up-regulated when pancreatic cancer cells were exposed to gemcitabine alone, suggesting the potential mechanism of acquired chemoresistance. In addition to in vitro results, we show here for the first time, that genistein in combination with gemcitabine is much more effective as an antitumor agent compared with either agent alone in our orthotopic tumor model. But most importantly, our data also showed that a specific target, such as NF-kappaB, was inactivated in genistein-treated animal tumors and that gemcitabine-induced activation of NF-kappaB was completely inhibited in animal tumors treated with genistein and gemcitabine. These results provide strong molecular in vivo evidence in support of our hypothesis that inactivation of NF-kappaB signaling pathway by genistein could also abrogate gemcitabine-induced activation of NF-kappaB resulting in the chemosensitization of pancreatic tumors to gemcitabine, which is likely to be an important and novel strategy for the treatment of pancreatic cancer.

Primary tumor of pancreatic cancer as a measurable target lesion in chemotherapy trials

BACKGROUND

It is unclear whether primary pancreatic cancer (PC) tumors can be accepted as measurable target lesions in chemotherapy trials. We reviewed recent PC patients to clarify the significance of their computed tomography (CT) responses of the primary tumor after chemotherapy.

METHODS

The patient selection criteria were (i) having been admitted between January 2002 and December 2004, (ii) diagnosed as having histologically or cytologically proven adenocarcinoma of the pancreas, (iii) treated with chemotherapy with no previous anticancer treatment and (iv) having been evaluated by follow-up CT to assess the response according to the Response Evaluation Criteria in Solid Tumors criteria.

RESULTS

A total of 143 patients met the selection criteria. It was possible to measure the largest diameter of the primary tumor in 119 (83%) of the 143, and primary tumor shrinkage was observed in 10 (8%) of the 119. When regarding the primary as measurable as opposed to non-measurable, the number of patients with measurable disease became 127 from 67, and the frequencies of partial response (PR), stable disease (SD) and progressive disease (PD) became 11, 74 and 15% of the 127 from 18, 52 and 30% of the 67, respectively. In the former situation, large primary tumor sometimes canceled the shrinkage or progression of small metastasis. In each setting, PR or SD represented a favorable prognosis compared with PD, however, there were no statistical differences between the PR and the SD.

CONCLUSION

Measuring the primary tumor is acceptable in approximately 80% of PC patients. However, we must be aware that the frequency of SD may increase compared with the PR or PD.