Tamoxifen regulation of sphingolipid metabolism--Therapeutic implications

Tamoxifen, a triphenylethylene antiestrogen and one of the first-line endocrine therapies used to treat estrogen receptor-positive breast cancer, has a number of interesting, off-target effects, and among these is the inhibition of sphingolipid metabolism. More specifically, tamoxifen inhibits ceramide glycosylation, and enzymatic step that can adventitiously support the influential tumor-suppressor properties of ceramide, the aliphatic backbone of sphingolipids. Additionally, tamoxifen and metabolites N-desmethyltamoxifen and 4-hydroxytamoxifen, have been shown to inhibit ceramide hydrolysis by the enzyme acid ceramidase. This particular intervention slows ceramide destruction and thereby depresses formation of sphingosine 1-phosphate, a mitogenic sphingolipid with cancer growth-promoting properties. As ceramide-centric therapies are becoming appealing clinical interventions in the treatment of cancer, agents like tamoxifen that can retard the generation of mitogenic sphingolipids and buffer ceramide clearance via inhibition of glycosylation, take on new importance. In this review, we present an abridged, lay introduction to sphingolipid metabolism, briefly chronicle tamoxifen's history in the clinic, examine studies that demonstrate the impact of triphenylethylenes on sphingolipid metabolism in cancer cells, and canvass works relevant to the use of tamoxifen as adjuvant to drive ceramide-centric therapies in cancer treatment. The objective is to inform the readership of what could be a novel, off-label indication of tamoxifen and structurally-related triphenylethylenes, an indication divorced from estrogen receptor status and one with application in drug resistance.

Factors impacting prognosis prediction in BCLC stage C and Child-Pugh class A hepatocellular carcinoma patients in prospective clinical trials of systemic therapy

BACKGROUND

The purpose of this study was to determine the prognostic significance of clinical factors and staging systems for survival of hepatocellular carcinoma (HCC) patients who are candidates for therapeutic clinical trials.

METHODS

From December 1990 to July 2005, 236 patients with unresectable HCC were enrolled into six published phase II trials assessing various therapeutic regimens. Of these, 156 chemotherapy-naive patients with Child-Pugh class A and Barcelona Clinic Liver Cancer stage C disease were included in this analysis. Twenty-seven relevant clinical characteristics were analyzed to identify prognostic factors of survival. Beyond these prognosticators, the predictive ability of eight staging systems (the tumor-node-metastasis, Okuda, Cancer of the Liver Italian Program [CLIP], Chinese University Prognostic Index, Japanese Integrated Staging, Tokyo, National Taiwan University Risk Estimation, and Advanced Liver Cancer Prognostic System [ALCPS] score) were compared using the Akaike information criteria.

RESULTS

The median overall survival time was 129 days (95% confidence interval, 111-147 days). Significant predictors of a shorter overall survival time were an Eastern Cooperative Oncology Group performance status score ≥2, the presence of symptoms, ascites, an aspartate transaminase level more than two times the upper limit of normal, and regional lymph node involvement. The ALCPS and CLIP scores were superior to the other systems for predicting survival.

CONCLUSIONS

The prognosis of patients with advanced HCC who are candidates for therapeutic clinical trials is affected by several factors related to the patient, liver function, and the tumor. The ALCPS and CLIP scores appear to be superior to the other systems for predicting survival.

Eastern Asian expert panel opinion: designing clinical trials of molecular targeted therapy for hepatocellular carcinoma

The largest burden of hepatocellular carcinoma (HCC) lies in Asia, secondary to hepatitis B virus (HBV) infection. Improved survival with sorafenib has fostered new research but many challenges remain in designing clinical trials. The disease, its management, and populations affected by it are heterogeneous worldwide and within Asia. An expert conference of Eastern Asian oncologists and hepatologists was convened to foster consensus in clinical trial design. The panel identified key areas that need to be addressed to facilitate clinical trials in Asia. Stratification by viral etiology is desirable within Asia and by region in global trials. Antiviral therapy should also be considered as a stratification factor and incorporated into HCC management in trials. The panel agreed that histological diagnosis is not required for trial entry and that Barcelona-Clinic Liver Cancer (BCLC) staging is acceptable for trials as long as portal hypertension can be better defined with standardized methodology. Consensus in treatment must be sought to allow multi-national trials and it must be recognized that first-line sorafenib is not largely feasible in Asia. Finally, Asian nations must be urged to participate in clinical trials, many of which are ongoing, to advance new treatment options in this challenging disease.

Efficacy and safety of epirubicin and etoposide combination chemotherapy in advanced hepatocellular carcinoma: a retrospective analysis

BACKGROUND AND AIM

Systemic treatments of advanced hepatocellular carcinoma (AHCC) have offered marginal clinical benefits. Recently, Italian investigators reported that etoposide and epirubicin combination (EE) chemotherapy was highly active against AHCC, with a response rate of 39% and a median overall survival (OS) of 10 months. We report our efficacy and safety results of EE in clinical practice.

METHODS

Between December 1999 and October 2005, 35 patients with AHCC and fitting the preset eligibility criteria were treated with EE. Twenty-eight patients (80%) had liver disease associated with hepatitis B virus (HBV) and 26 (74%) had a prior history of transarterial chemoembolization (TACE) using cisplatin. The EE chemotherapy consisted of epirubicin 40 mg/m(2) on day 1 and etoposide 120 mg/m(2) on days 1, 3 and 5 every 4 weeks.

RESULTS

A total of 102 chemotherapy cycles were administered, with a median of two cycles per patient (range one to eight cycles). Two patients had a partial response and nine had stable disease, with a tumor control rate of 32% (95% CI 17-48). The median progression-free survival (PFS) was 2.1 months (95% CI 1.8-2.4) and the median OS was 6.4 months (95% CI 4.4-8.5). There was a tendency toward improved PFS in patients seronegative for HBsAg and peritoneal seeding (P = 0.06 and P = 0.054, respectively). Overall survival was significantly better in patients without HBsAg and Cancer Liver Italian Program (CLIP) score 0-1 (P = 0.024 and P = 0.033, respectively). The main toxicities were hematological events, including grade 3/4 neutropenia in 29% and febrile neutropenia in 11% of patients.

CONCLUSION

Treatment with EE showed minimal antitumor activity with acceptable toxicity in HBV-associated AHCC, especially in patients pretreated with TACE.

Systemic therapy for advanced hepatocellular carcinoma: a review

Hepatocellular carcinoma (HCC) is a common cause of cancer mortality worldwide. Whilst local treatments are useful in selected patients, they are not suitable for many with advanced disease. Here, we review phase II and III trials for systemic therapy of advanced disease, finding no strong evidence that any chemotherapy, hormonal therapy, or immunotherapy regimen trialled to date benefits survival in this setting. Many trials were inadequately powered, single centre, and enrolled highly selected patients. From this review, we cannot recommend any therapeutic approach in these patients outside of a clinical trial setting. Including an untreated control arm in clinical trials in HCC is still justified. Every effort should be made to enroll these patients into adequately powered trials, and promising phase II results must be tested in a multicentre phase III setting, preferably against a placebo control arm. Prevention of hepatitis B and C remains vital to decrease deaths from HCC.

Beta 1-integrin protects hepatoma cells from chemotherapy induced apoptosis via a mitogen-activated protein kinase dependent pathway

BACKGROUND

beta 1-integrin modulates cellular phenotype by mediating signals from the extracellular matrix (ECM). Although overexpression of integrin molecules in hepatocellular carcinoma (HCC) has been reported, the role of overexpressed beta 1-integrin in the disease process of HCC is not fully understood. The authors investigated the effects of beta 1-integrin on apoptosis in hepatoma cells.

METHODS

Human hepatoma cell lines HepG2, Huh7, and HLE were stably transfected with full-length beta 1-integrin. Cells underwent apoptosis induced by chemotherapeutic reagents, including cis-platinum (II)-diammine dichloride, etoposide, and docetaxel. Cell survival and intracellular signaling pathways dependent on beta 1-integrin-mediated apoptosis effects were analyzed by treating cells with PD98059 (ERK inhibitor), SB203580 (p38MAP kinase inhibitor), wortmannin (phosphatidyl inositol-3-kinase inhibitor), and herbimycin A (tyrosine kinase inhibitor).

RESULTS

All three hepatoma cell lines overexpressing beta 1-integrin were protected from apoptosis induced by chemotherapeutic reagents, whereas parental or mock transfected cells were not. Treatment with PD98059 or SB203580 abolished the protective effect on apoptosis in cells overexpressing beta 1-integrin. Neither herbimycin nor wortmannin blocked the protective effects of beta 1-integrin overexpression.

CONCLUSIONS

These data suggest that overexpression of beta 1-integrin confers resistance to apoptosis in hepatoma cells via a MAP kinase dependent pathway. beta1-integrin mediated signaling from the ECM in HCC cells may contribute to chemotherapy resistance.

Basal levels and patterns of anticancer drug-induced activation of nuclear factor-kappaB (NF-kappaB), and its attenuation by tamoxifen, dexamethasone, and curcumin in carcinoma cells

Nuclear factor-kappaB (NF-kappaB) has been implicated in the development of drug resistance in cancer cells. We systematically examined the baseline levels of NF-kappaB activity of representative carcinoma cell lines, and the change of NF-kappaB activity in response to a challenge with four major anticancer drugs (doxorubicin, 5-fluorouracil, cisplatin, and paclitaxel). We found that the basal level of NF-kappaB activity was heterogeneous and roughly correlated with drug resistance. When challenged with various drugs, all the cell lines examined responded with a transient activation of NF-kappaB which then declined to basal level despite variation in the concentration of the agent and the timing of the treatment. In contrast to tumor necrosis factor-alpha (TNF-alpha), which activates NF-kappaB in minutes, NF-kappaB activation induced by anticancer drugs usually occurred more than 1hr after stimulation. A gradual increase of total NF-kappaB and its nuclear translocation, and cytoplasmic translocation of nuclear IkappaBalpha and its degradation were involved in this process. In particular, when cells were pretreated with common biologic modulators such as tamoxifen, dexamethasone, and curcumin, the doxorubicin-induced NF-kappaB activation was attenuated significantly. This inhibition may play a role in sensitizing cancer cells to chemotherapeutic drugs. This study has demonstrated that activation of NF-kappaB is a general cellular response to anticancer drugs, and the mechanism of activation appears to be distinct from that induced by TNF-alpha. These observations may have implications for improving the efficacy of systemic chemotherapy for cancer patients.

Liver cancer

The prognosis of patients with HCC remains dismal. Even in the subgroups of patients who have the most favorable characteristics and are eligible for surgical resection, the 5-year survival rate is less than 25%. For patients with more advanced disease, the median survival time is less than 1 year. The good news in HCC research is that the disease can be prevented. In Taiwan, the rate of HCC in children aged 6 to 9 years decreased from 5.2 per million population before the neonatal vaccination program began in 1984 to 1.3 per million population in the first vaccinated cohort. Treatment of viral hepatitis with IFN may decrease the rates of long-term development of HCC. Other agents that may prevent second primary tumors following resection of HCC, such as polyprenoic acid and acylic retinoid, are also being investigated.

Nonsurgical treatment of hepatocellular carcinoma

Given the poor prognosis of HCC and the therapeutic challenge posed by underlying liver cirrhosis, efforts and resources must be directed towards preventive strategies. Return on the investment in such research is likely to be greater than can be expected from treatment of advanced disease.

[Hepatocellular carcinoma. Part 2. Treatment]

Recent improvements on the therapeutical management of hepatocellular carcinoma are revised with special attention to evaluate the role of surgery for the disease. Considering that definitive surgical intervention is not feasible in most cases because of extreme tumor extension, multiplicity of tumor foci, and associated advanced liver cirrhosis at the time of diagnosis, others forms of treatment are listed, such as transcatheterarterial chemoembolization, percutaneous ethanol and acetic acid injections, and chemotherapy only to a small portion of patients with no indication for standard treatments. The emerging role of retinoic acid metabolism blocking agents, was examined and may offer a significant new potential treatment for cancer, inclusive the possibility of combining other anticancer drugs with exogenous retinoids or modulation of endogenous retinoids as a real opportunity to advance our ability to treat or prevent human cancer effectively Octreotide, nitrosamine and other drugs are analyzed and is concluded that improves survival and is a valuable alternative in the treatment of inoperable hepatocellular carcinoma. The potential role of intersticial laser coagulation for patients with irresectable hepatic tumors was investigated, and in terms of experience, it has now been developed sufficiently to study its effect on these patients survival. The homeostatic control of angiogenesis and its influences on the tumor growth and for migration of metastatic cells, was focused in this concise review, given that hepatocytes are the source of much of the precursor pool, regulation of angiogenesis may be regarded as a new liver function with important consequences for tissue repair and cancer. Early hepatocellular carcinoma and its recognition in routine clinical practice contributes to improved patients survival. Recombinant-Interferon-alpha therapy surely prevents, the development of cirrhosis or hepatocellular carcinoma in about one-third of patients, with chronic hepatitis C, with sustained response. Finally, in individuals with life-threatening liver disease, such as those with cirrhosis and hepatocellular carcinoma, the liver transplantation, must be considered, besides controversial, however, with increasing experience the results of the procedure in these patients have improved, and may offer a better long-term survival than liver resection.

Transcatheter arterial chemoembolization for hepatocellular carcinoma in patients with Child's grade A or B cirrhosis: a multivariate analysis of prognostic factors

We evaluated factors affecting long-term survival after transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) complicating cirrhosis. One hundred eighty-two patients with Child's class A or B cirrhosis and an HCC, not amenable to surgery or percutaneous ethanol injection, underwent 346 TACEs (mean 1.9) with epirubicin, iodized oil, and gelatin sponge. Many prognostic factors were subjected to univariate analysis and thereafter, when significant, to the Cox's hazard proportional model. Finally, the significant indices in the Cox's model were used to estimate the accuracy of the probability of death with computation of the area under the receiving operative characteristic (ROC) curve. The cumulative survival rates at 1, 2, 3, and 5 years were 0.83, 0.52, 0.40, and 0.16, respectively. According to Cox's model, the factors associated with significantly worse survival were the presence of ascites (p = 0.0027), elevated bilirubin levels (p = 0.0163), elevated alpha-fetoprotein (alphaFP) values (p = 0.0067), a tumor greater than 5 cm in diameter (p = 0.0001), and the absence of a tumor capsule-like rim (p = 0.0278). According to these parameters, the accuracy of the probability of death estimated with ROC analysis was 0.63. Minor and major complications occurred in 82 patients (45%) and caused death in 2 patients. Long-term prognosis after TACE for HCCs in patients with Child's class A or B cirrhosis depends on the presence of ascites, the bilirubin level, the alphaFP value, the diameter of the tumor, and the presence of a tumor capsule-like rim. However, when considered altogether, these variables are poor predictors to evaluate survival, and other factors should be investigated to identify subjects more responsive to TACE. Complications occur in a high percentage of patients, but they do not affect long-term prognosis.

Sex and androgenic steroid receptor expression in hepatic adenomas

Sex hormones and anabolic-androgenic steroids are implicated in the development and progression of hepatic adenomas (HA). We studied the expression of their receptors in HA and adjacent liver. Archival tissue sections of 27 HA (16 resections, four needle biopsies, seven aspirations) from 18 patients, and the adjacent liver, were immunostained with monoclonal antibody to estrogen receptor (ER, 1/80) (Dako, Carpinteria, CA), progesterone receptor (PR, 1/50) (BioGenex, San Ramon, CA), and androgen receptor (AR, 1/80) (BioGenex). An avidin-biotin complex technique was used with microwave antigen retrieval. Nuclear expression was assessed as 1+ to 3+ intensity, with semiquantitation of the percentage of nuclei immunopositive. Five percent or more nuclei immunopositive was regarded as positive. The 18 patients included 16 females of 34 years mean age (range, 16 to 49) with an available history of oral contraceptives in five; the two men were 24 and 30 years, with no history of androgenic steroids. ER, PR, and AR were present in seven (26%) (1+/-2+ intensity, 5% to 10% of nuclei) of HA, seven (26%) (1+/-2+ intensity, 5% to 30% of nuclei) and nine (33%) (1+/-3+ intensity, 5% to 80% of nuclei), respectively. In the adjacent liver in 11 cases, there were one (9%) ER, (2+ intensity, 5% of nuclei), four (36%) PR (1+/-2+ intensity, 5% to 20% of nuclei), and two (18%) AR (2+/-3+ intensity, 10% of nuclei). Receptors are present and may mediate the action of sex hormones or androgenic steroids on HA and adjacent liver, but in less than one third of patients. This may have therapeutic implications.

Endocrine treatment of hepatocellular carcinoma. Any evidence of benefit?

In the past 20 years, a number of studies have investigated the relationship between sex hormones and liver cancer. Experimental studies indicate that a dynamic process, with sequential modifications in the pattern of sex hormones in the serum and of sex hormone receptors in the liver, occurs progressively during hepatocarcinogenesis. Overall, it seems that both androgens and oestrogens may enhance liver carcinogenesis, while androgens may also support the growth of established liver tumours. Unfortunately, clinical studies of endocrine treatment of hepatocellular carcinoma (HCC) have not adequately tested the suggestions from biological studies. So far, no clinical trial has been performed to test the efficacy of endocrine manipulation for the chemoprevention of HCC in cirrhotic patients nor in preventing relapse after radical resection of primary HCC. Anti-oestrogens have been the most studied agents for the endocrine treatment of established HCC, although the rationale that supports their use is weaker than for anti-androgens. Studies with anti-androgens have produced prevalently negative results, due to either a lack of activity or excessive toxicity. The use of chemical castration, which theoretically could enhance the activity of antihormonal compounds, yielded no benefit at all. In summary, there is, as yet, no definitive evidence that endocrine treatment favourably affects the outcome of patients with HCC.

Non-surgical treatment of hepatocellular carcinoma

A decade ago, surgery was the only satisfactory treatment modality for hepatocellular carcinoma (HCC), but it was limited only to selected cases. For the majority of cases of HCC, systemic chemotherapy was one of the few treatment alternatives, but provided only marginal benefit. In the past 20 years, diagnostic methods have improved to an extent that small HCC less than 1 cm can be detected. Moreover, non-surgical treatment is available, of which regional therapy has been shown to prolong patients' survival, and may even replace surgical resection in some cases. Regional therapy is indicated for the treatment of HCC when there is no extrahepatic metastasis and the patient has adequate liver function reserve, thus permitting repeated therapy. Transcatheter hepatic arterial embolization (TAE) using various embolizers has been well documented to include controlled studies. However, it is not indicated for patients with thrombosed main portal veins. Its therapeutic effect is also doubtful when the tumour is infiltrative in nature or is hypovascular, too large or too small. Additional chemotherapeutic agents mixed into the embolizer with lipiodol and degraded starch microspheres or styrene-maleic acid-neocarzinostatin in which chemotherapeutic agents are embedded, are used with a better response, but the survival rate has not shown significant improvement. Ultrasound-guided local injection therapy is another new method of treatment of HCC. Of these techniques, percutaneous ethanol injection therapy (PEIT) is widely used with excellent results for small, encapsulated tumours in livers with less than three HCC. Percutaneous ethanol injection therapy can also be used in cases with portal vein thrombosis, but it is not suitable for patients having coagulopathy or ascites. Using acetic acid, OK-432, interferon or anti-cancer drugs in the injection therapy shows no further benefit over ethanol alone. Transcatheter echoguided thermotherapy or cryotherapy has been reported in small series of patients, as has target therapy with immune or radiotherapy and conformal radiotherapy. Preliminary studies show encouraging results. Systemic therapy with either single drug or multidrugs is ineffective, with a response rate of less than 20%. Immunotherapy, such as with interferon or other cytokines, is not beneficial. Hormone therapy has not been promising, except for treatment with tamoxifen, which has been reported to show some beneficial effect. Gene therapy is still in its infancy. In summary, recent progress in non-surgical treatment of HCC has resulted in a breakthrough of regional therapy looking quite promising. Moreover, a combination of different types of regional therapies may yield better outcomes in selected individuals.

Expression of P-glycoprotein and p53 in advanced hepatocellular carcinoma treated by single agent chemotherapy: clinical correlation

Hepatocellular carcinoma (HCC), a chemoresistant tumour, is the most common fatal cancer in Taiwan. Hepatocellular carcinoma frequently expresses a high level of P-glycoprotein (P-gp), which is a specific phenotype of a multidrug-resistance gene, and harbours mutations of the tumour suppressor gene p53. A modulatory relationship between p53 and P-gp has been reported. In this study, we analysed the expression of P-gp in relation to chemotherapeutic response and p5353 protein expression in advanced HCC. Prechemotherapeutic tumour samples were obtained from 25 patients with HCC which had been treated with either etoposide (VP-16) or doxorubicin. P-glycoprotein and p53 in HCC were visualized by immunohistochemical staining using the monoclonal antibodies JSB-1 and DO1, respectively. We investigated the correlation of P-gp expression with chemotherapeutic responses, clinicopathological features and p53 protein expression. In our study, seven cases achieved partial remission, and the remaining 18 cases had a poor response to chemotherapy. Expression of P-gp was observed in 13 tumours (52%). Positive P-gp protein expression was significantly associated with non-responders (8% or 1/13 vs 50% or 6/12, P = 0.03). Thus, P-gp expression inversely correlated with chemotherapeutic response. Expression of p53 protein was seen in 12 cases and did not correlate with chemosensitivity or P-gp expression. In summary, P-gp expression correlates with the chemosensitivity of HCC that has been treated with VP-16 or doxorubicin and p 53 mutations do not appear to be a major determinant of P-gp expression in advanced HCC.