Proposed treatment of cancer by inhibition of gluconeogenesis

PCK1 dysregulation in cancer: Metabolic reprogramming, oncogenic activation, and therapeutic opportunities

The last few decades have witnessed an advancement in our understanding of multiple cancer cell pathways related to metabolic reprogramming. One of the most important cancer hallmarks, including aerobic glycolysis (the Warburg effect), the central carbon pathway, and multiple-branch metabolic pathway remodeling, enables tumor growth, progression, and metastasis. Phosphoenolpyruvate carboxykinase 1 (PCK1), a key rate-limiting enzyme in gluconeogenesis, catalyzes the conversion of oxaloacetate to phosphoenolpyruvate. PCK1 expression in gluconeogenic tissues is tightly regulated during fasting. In tumor cells, PCK1 is regulated in a cell-autonomous manner rather than by hormones or nutrients in the extracellular environment. Interestingly, PCK1 has an anti-oncogenic role in gluconeogenic organs (the liver and kidneys), but a tumor-promoting role in cancers arising from non-gluconeogenic organs. Recent studies have revealed that PCK1 has metabolic and non-metabolic roles in multiple signaling networks linking metabolic and oncogenic pathways. Aberrant PCK1 expression results in the activation of oncogenic pathways, accompanied by metabolic reprogramming, to maintain tumorigenesis. In this review, we summarize the mechanisms underlying PCK1 expression and regulation, and clarify the crosstalk between aberrant PCK1 expression, metabolic rewiring, and signaling pathway activation. In addition, we highlight the clinical relevance of PCK1 and its value as a putative cancer therapeutic target.

Revisiting the Warburg Effect: Diet-Based Strategies for Cancer Prevention

It is widely acknowledged that cancer cell energy metabolism relies mainly on anaerobic glycolysis; this phenomenon is described as the Warburg effect. However, whether the Warburg effect is caused by genetic dysregulation in cancer or is the cause of cancer remains unknown. The exact reasons and physiology of this abnormal metabolism are unclear; therefore, many researchers have attempted to reduce malignant cell growth in tumors in preclinical and clinical studies. Anticancer strategies based on the Warburg effect have involved the use of drug compounds and dietary changes. We recently reviewed applications of the Warburg effect to understand the benefits of this unusual cancer-related metabolism. In the current article, we summarize diet strategies for cancer treatment based on the Warburg effect.

Parenteral Hyperalimentation in Patients with Advanced Neoplastic Disease

Two groups of patients suffering from advanced neoplastic disease were fed parenterally for a period ranging from 1 to 16 weeks. The parameters considered were: weight change, serum albumin level, lymphocyte transformation test and serum immunoglobulin level. There were 23 patients in one group and 21 patients in the other. Regimens included for group I: saline solution (1000–1500 ml), glucose (100–150 g) and amino acids (15–30 g) per day; for group 2: 40–50 Cal/kg per day (dextrose about 15 g/kg per day), about 2 g of amino acids/kg/day and about 40–50 ml water/kg/day. In addition, 13 patients underwent both treatments sequentially. All the Group I patients lost weight (1.3 kg/week); while out of 23 patients in Group 2, 15 gained weight, 2 remained unchanged and 6 continued to lose weight, but to a lesser rate than before hyperalimentation (the average weight gain was 1.1 kg/week). Serum albumin levels decreased in 19 out of 25 patients in Group I and increased in 14 out of 26 patients of Group 2. Initial values of the lymphocyte blast transformation test were very low in both groups of patients, and an increase was observed only in patients treated by hyperalimentation. The increase was more evident in patients who were not under antiblastic treatment. Changes in serum immunoglobulin levels were not significant. The authors conclude that malnutrition plays a very important role in neoplastic cachexia and can be improved by parenteral hyperalimentation. Although it is possible that in the near future hyperalimentation and conventional neoplastic therapies will play complementary roles in treatment of advanced neoplastic disease, malnutrition is still the specific indication for intravenous hyperalimentation.

Metabolic adaptation to cancer growth: from the cell to the organism

Tumour cells proliferate much faster than normal cells; nearly all anticancer treatments are toxic to both cell types, limiting their efficacy. The altered metabolism resulting from cellular transformation and cancer progression supports cellular proliferation and survival, but leaves cancer cells dependent on a continuous supply of energy and nutrients. Hence, many metabolic enzymes have become targets for new cancer therapies. In addition to its well-described roles in cell-cycle progression and cancer, the cyclin/CDK-pRB-E2F1 pathway contributes to lipid synthesis, glucose production, insulin secretion, and glycolytic metabolism, with strong effects on overall metabolism. Notably, these cell-cycle regulators trigger the adaptive "metabolic switch" that underlies proliferation.

Primer on integrative oncology

At the present time, there is no obvious answer for many of these design difficulties. This problem will continue to constrain ability to determine the efficacy of integrative medical techniques for patients who have cancer. Patients, however, will continue to gravitate toward alternative treatments, especially when standard cancer treatments fail. Therefore oncologists must be aware of alternative medical agents and techniques, and be able to guide their patients, rather than simply being dismissive.

Cancer cachexia demonstrates the energetic impact of gluconeogenesis in human metabolism

A review-based hypothesis is presented on the energy flow in cancer patients. This hypothesis centres on the hypoxic condition of tumours, the essential metabolic consequences, especially the gluconeogenesis, the adaptation of the body, and the pathogenesis of cancer cachexia. In growing tumours the O(2) concentration is critically low. Mammalian cells need O(2) for the efficient oxidative dissimilation of sugars and fatty acids, which gives 38 and 128 moles of ATP per mole glucose and palmitic acid, respectively. In the absence of sufficient O(2) they have to switch to anaerobic dissimilation, with only 2 moles of ATP and 2 moles of lactic acid from 1 mole of glucose. Since mammalian cells cannot ferment fatty acids, in vivo tumour cells completely depend on glucose fermentation. Therefore, growth of these tumour cells will require about 40 times more glucose than it should require in the presence of sufficient O(2). Since lactic acid lowers the intracellular pH, it decreases the activity of pyruvate dehydrogenase, stimulates fermentation, and thus amplifies its own fermentative production. Compensatory glucose is provided by hepatic gluconeogenesis from lactic acid. However, the liver must invest 3 times more energy to synthesize glucose than can be extracted by tumour cells in an anaerobic way. The liver extracts the required energy from amino acids and especially from fatty acids in an oxidative way. This may account for weight loss, even when food intake seems adequate. In the liver 6 moles of ATP are invested in the gluconeogenesis of one mole of glucose. The energy content of 4 out of these 6 moles of ATP is dissipated as heat. This may account for the elevated body temperature and sweating experience by cancer patients.

Clinical usage of hypolipidemic and antidiabetic drugs in the prevention and treatment of cancer

Factors predisposing hormone-dependent tissues to the development of tumors coincide, at least partly, with hormonal-metabolic promoters (like insulin resistance, glucose intolerance, visceral obesity, etc.) of other main non-communicable diseases. This important knowledge poses the question of whether the same approach which is applied for prevention/treatment of a metabolic syndrome and the associated endocrine disorders might also be used in preventive and therapeutic oncology. Whereas an answer to this question remains controversial and is based mainly on experimental evidence, there is accumulating clinical data suggesting a practical significance of such a strategy, even though it is not to be considered as directly cytostatic. Among the many drugs under discussion, three groups of medicines (statins, antidiabetic biguanides, and thiazolidinediones) are the most attractive. The concept of metabolic rehabilitation is proposed and used practically in an adjuvant setting for the correction of the above-mentioned endocrine-metabolic disorders commonly found in cancer patients. The current use and aim of this approach is to improve the survival of patients and limit cancer progression. Nonetheless, it also appears potentially useful as a neoadjuvant therapy as well as a prophylactic treatment earlier in life for specific groups of people with hormone-associated enhanced oncological risk. It seems possible that certain hypolipidemic and antidiabetic medicines with pleiotropic effects might be combined with traditional antisteroid prevention/therapeutic approaches in routine clinical situations as well as for overcoming resistance to standard cancer hormonal therapies including receptor-negative cases. Characteristic at the end of the 20th and at the beginning of the 21st century is an epidemic of diabetes and obesity, which might further increase the incidence of certain cancers. This makes it timely to apply hypolipidemic and antidiabetic drugs (in combination with reasonable dieting, increased physical fitness, and an in-depth knowledge of drug-gene interactions) as an approach warranting further study.

How useful are unconventional cancer treatments?

Unconventional cancer treatments are used frequently. Therefore, oncologists need to know about them. This article gives an overview of current knowledge on the most prevalent complementary or alternative cancer therapies. A distinction is made between alleged cures, preventive and adjunctive measures. Shark cartilage, mistletoe, thymus therapy, essiac, hydrazine sulphate, 714-X, dietary regimens, green tea and Panax ginseng are all covered specifically. None of these treatments offer reasonable hope for a cure. Some strategies are promising in terms of cancer prevention. The true potential of unconventional therapies might lie in adjunctive and palliative care. It is concluded that good evidence in this area is scarce. Vis-à-vis the high prevalence of unconventional cancer treatments, rigorous investigations are mandatory, not least for increasing the safety of future patients.

Glycogen synthesis in tumor-bearing rats after ingestion of a high-glycerol meal

Tumor-bearing rats have a high rate of postprandial hepatic glycogen synthesis by the indirect pathway that involves gluconeogenesis. This study was designed to investigate the role of glycerol as a precursor for postprandial glycogen synthesis in tumor-bearing rats. Rats bearing a Leydig cell tumor and freely fed controls were fasted overnight, then fed a 16-kJ meal with or without 50 mg of glycerol by gavage. [U-14C]glycerol (1 microCi) was also administered intragastrically, and 7 mCi of 3H2O were injected intraperitoneally. The rats were killed one hour later, and the specific activities at different positions within the glycogen glucose residues in the liver were measured. Increasing the glycerol content of the meal had no significant effect on the overall incorporation of 3H into liver glycogen or on the proportion of glycogen synthesized via pyruvate in tumor-bearing or control rats. There was no difference between tumor-bearing and control rats in the amount of glycerol incorporated into glycogen, although this was increased by the high-glycerol meal. Thus glycerol appeared to make a small contribution to postprandial glycogen synthesis in tumor-bearing and control rats.

Cytokines and cachexia

Prolonged production of cytokines associated with cancer and chronic infections, and other long-term immune reactions is increasingly recognized as a main causal factor of the often severe signs and symptoms that accompany these diseases: weight loss, anorexia, and metabolic breakdown termed cachexia. The cytokine that initially was held responsible for causing these changes was tumor necrosis factor (TNF). However, from various studies it has become clear that the action of TNF can only be understood in the context of simultaneous presence of other cytokines, some of which have activities that are at the least equally important as TNF in bringing about cachexia. This review summarizes the experimental evidence for the involvement of cytokines in the pathogenesis of cachexia. Indirect evidence comes from the observation that cachexia can be induced in animals by repeated injections of cytokines or by inoculation of cytokine-producing cells. Thus, cachexia has been described in mice inoculated with tumor cells carrying and expressing genes for either TNF, interleukin-6 (IL-6), leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF) and interferon-gamma (IFN-gamma). More direct evidence is provided by the observations that cachexia in experimental animal models can be mitigated by administration of specific antagonists of cytokines. These latter type of studies revealed that cachexia can rarely, if ever, be attributed to one single cytokine but rather to a set of cytokines that work in concert in cachexia. A pool of anticytokine antibodies or other cytokine inhibitors might, therefore, be considered as a potential intervention for the treatment of cachectic patients, but this approach may induce immunosuppression, and, therefore, danger exists that such treatment may benefit the infectious agent or tumor.

Total nutritional manipulation in humans: report of acancer patient

We report here on a patient requiring home total parenteral nutrition (TPN) for a huge intra-abdominal desmoid associated with chronic small bowel pseudo-obstruction who was kept on a special lipid-based calorie regimen for 5 months. The rationale was to attempt to feed the host with a minimal stimulation of tumour growth by using lipid as caloric substrate instead of glucose which is utilized by the tumour. Gluconeogenesis was tentatively inhibited at the level of phosphoenolpyruvate-carboxy-kinase through the oral intake of hydrazine sulphate. The regimen consisted of 28 non-protein lipid Kcal/kg/day plus 1.5 g amino acid per kg/day. Only a small amount of glucose (approx. 40 g/day) was allowed. Tolerance to the regimen was good and body weight maintained. Liver enzymes remained within the normal range and liver sonography was normal throughout the 5 months' therapy and there were no episodes of symptomatic hypoglycaemia. The tumour volume did not substantially change.

Altered metabolism and mortality in patients with colon cancer receiving chemotherapy

To identify the metabolic effects of 5-fluorouracil and hydrazine sulfate therapy, 22 patients with colon cancer were admitted prospectively to a Clinical Research Center for serial measurement of counter-regulatory hormones, fasting hepatic glucose production (HGP), intravenous glucose tolerance test, plasma leucine appearance (LA) and leucine oxidation. Combined therapy was associated with a significant reduction in fasting glucose level (98 +/- 2 mg/dL to 94 +/- 2, P < 0.025) without a significant fall in fasting HGP (2.09 +/- 0.11 mg/kg/min versus 2.03 +/- 0.13; P > 0.05). The decreased fasting glucose value was associated with a mild but not statistically improved glucose disposal rate in response to the intravenous glucose tolerance test (1.34 +/- 0.07 %/min vs 1.47 +/- 0.11, P = 0.15). Plasma leucine appearance was significantly reduced after 2 months of therapy (63.3 +/- 3.0 mumol/kg/hr vs 57.1 +/- 3.9 mumol/kg/hr; P < 0.025), but leucine oxidation (11.5 +/- 1.1 mumol/kg/hr vs 11.2 +/- 1.1 mumol/kg/hr) was not altered. Despite the fact that plasma triiodothyronine concentrations significantly increased with therapy, it was not associated with plasma LA. Half of the patients with cancer died 14 +/- 4 months after the study, and the other half were alive 58 +/- 2 months later. Survival time can be estimated with 59% accuracy using plasma LA, HGP, carcino-embryonic antigen, and insulin concentration. Multiple regression analysis identified that plasma LA was related directly to length of survival time, and baseline HGP, carcino-embryonic antigen, and insulin concentration were related inversely to length of survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Nutritional and physiological consequences of tumour glycolysis

A frequent characteristic of many malignant tumours is an increase in anaerobic glycolysis, that is the conversion of glucose to lactate, when compared to normal tissues. The causes of this intensification involve changes in enzyme and glucose transporter levels, shifts of the isoenzyme patterns in the cancer cells to those similar to foetal tissues and a breakdown in the normal control mechanisms, most notably the Pasteur effect. The host must adapt, with a corresponding increase in gluconeogenesis. This change, along with other adaptations made by the host, eventually results in the syndrome known as cancer cachexia, which is characterized by anorexia and depletion and redistribution of the host energy stores. In some ways many malignant tumours behave much like parasites, drawing upon the host for nutrients such as glucose and returning waste products such as lactate to the host for recycling or disposal. This cycling of glucose and lactate between host and tumour has been the target for a number of proposed and tested treatments, with regard to the possible inhibition of tumour growth and/or possible prevention of some or all of the cachectic effects. Some of these suggested treatments have reached the point of clinical testing and show promise for continued research.

[Nitrogen balance in tumor and host in the animal model]

The importance of malnutrition as major cause of morbidity and mortality in cancer patients is well documented. It has been shown that nutritional therapy improves well-being and nutritional status of the patient, but the tumor can also be accelerated by hypercaloric nutrition. Our study does not confirm the induction of tumor growth. A high positive metabolic rate of the host lowers the tumor's growth rate and its tendency to spread. The retention of nitrogen in host increase with decreasing rate of energy and nutrition. Our results show that the tumor itself uses energy and nutrients from host cell catabolism and does not directly exploit exogenous nutrient substrates. It should not be forgotten that the animal model leads to specific changes affecting the energy and nutrient metabolism.

Nutritional pharmacology in the treatment of neoplastic disease

The altered energy metabolism and substrate requirements of tumour cells can provide a target for selective antineoplastic therapy. The supply of substrates for tumour energy metabolism can be reduced by dietary manipulation (e.g. ketogenic diet) or by pharmacological means at the cellular level (e.g. inhibitors of glycolysis or oxidative phosphorylation). Both these approaches are examined with a view to the development of selective and therefore non-toxic methods of controlling tumour growth in vivo.

Effect of hydrazine sulphate on whole-body protein breakdown measured by 14C-lysine metabolism in lung cancer patients

In a prospective double-blind trial twelve malnourished patients with lung cancer were randomised to receive either placebo or hydrazine sulphate (60 mg three times daily) for 30 days. Fasting lysine flux was determined by a primed 4-hour continuous infusion of 14C-lysine before and after one month of hydrazine treatment. Baseline plasma lysine flux was 2580 (SD 580) mumol/h for the placebo group and 2510 (440) mumol/h for the hydrazine group. After one month the placebo group showed a slight rise to 2920 (450) mumol/h (p = 0.08) and the hydrazine group showed a significant fall to 1840 (750) mumol/h (p less than 0.05); serum albumin fell in the placebo group and was unchanged in the hydrazine group. Administration of hydrazine sulphate to reduce aminoacid flux may favourably influence the metabolic abnormalities in cancer cachexia.

Hydrazine sulfate in cancer patients with weight loss. A placebo-controlled clinical experience

Hydrazine sulfate was evaluated using 24-hour dietary recalls and body weight determinations before and after 30 days of either placebo or hydrazine (60 mg, 3 times/d) oral administration in 101 heavily pretreated cancer patients with weight loss. After 1 month, 83% of hydrazine and only 53% of placebo patients completing repeat evaluation maintained or increased their weight (P less than 0.05). In addition, appetite improvement was more frequent in the hydrazine group (63% versus 25%, P less than 0.05). Although caloric intake was only slightly greater in hydrazine-treated patients, an increased caloric intake was more commonly associated with weight gain in patients receiving hydrazine compared with those receiving placebo (81% versus 53%, respectively). Hydrazine toxicity was mild, with 71% of patients reporting no toxic effects. Hydrazine sulfate circulatory levels were obtained from a subset of 14 patients who completed 30 days of treatment, with a single sample obtained in the morning at least 9 hours after the last dose. Mean maintenance hydrazine sulfate levels, determined using a spectrofluorometric assay, ranged from 0 to 89 ng/ml (mean 45 +/- 16 ng/ml). These data, which demonstrate an association between 1 month of hydrazine sulfate administration and body weight maintenance in patients with cancer, suggest future clinical trials of hydrazine sulfate are indicated to definitively assess its long-term impact on important clinical outcome parameters in defined cancer populations.

Hydrazine sulfate: a current perspective

Hydrazine sulfate is an anticachexia agent which interrupts host energy wasting as a result of the malignant process. An inhibitor of gluconeogenesis at the phosphoenolpyruvate carboxykinase (PEP CK) reaction, this agent has been shown in randomized, placebo-controlled, double-blind trials to improve glucose tolerance, reduce glucose turnover, increase caloric intake, and increase or stabilize weight; in single-arm controlled trials, this agent has been shown to increase appetite, improve performance status, decrease pain, diminish anorexia, normalize laboratory indices, stabilize tumor growth, induce tumor regression, and promote survival, while inducing little to no important clinical side effects. In view of its demonstrated capacity to effect anticancer response, this drug is suggested for trial as a sole agent in early drug-resistant cancer, in combination with cytotoxic and related therapies, and in conjunction with total parenteral nutrition. It is postulated that effective control of the mechanisms associated associated with cancer cachexia may contribute to control of malignant disease.

Cancer cachexia

Cancer cachexia is a complex syndrome that includes host tissue wasting, anorexia, asthenia, and abnormal host intermediary metabolism. It is present in approximately 50% of cancer patients during treatment and nearly 100% of treated cancer patients at death. Cachexia has a detrimental impact on cancer therapy. The central problem of cancer cachexia is that energy balance is not maintained, and the host has a relative hypophagia which results in host tissue wasting. The tumor by its nature and obligate growth can continue to consume glucose, amino acids, and lipids at the expense of the host. This produces abnormal host intermediary metabolism including elevated glucose production and recycling, decreased muscle protein synthesis, and increased muscle and fat breakdown. The exact mechanisms of cancer cachexia have been only partially elucidated. The identification of signal molecules like cachectin which mediate these changes may be on the horizon. Nutritional support can reverse some of the derangements seen with cachexia, and there is evidence that functional lean body mass or body cell mass can be restored in some (but not all) patients. However, nutritional support has not yet improved response to chemotherapy or radiation therapy, nor has it improved host tolerance of chemotherapy. It has improved operative mortality and morbidity in cachectic cancer patients undergoing major surgical procedures. Optimum host nutritional support appears to be dependent on high insulin concentrations in both humans and rats. Insulin and exercise may be methods to preserve host lean tissue and feed the host rather than the tumor. Future studies depend on better definition of tumor-bearing host metabolism, altering the relationship between neoplasm and host to preferentially feed the host, and making the neoplasm more susceptible to effective treatment.

Metabolic abnormalities in cancer patients: carbohydrate metabolism

Weight loss in patients with a variety of cancers is associated with a poor prognosis. Consistent abnormalities of carbohydrate metabolism are seen in cancer patients with weight loss and appear to represent derangements in host metabolism that are induced by the presence of cancer. To define therapeutic strategies to improve the poor clinical outcome for patients with cancer cachexia, investigations are under way to define the relationships among glucose metabolism, altered energy expenditure, caloric intake, weight loss, and clinical outcome.

Fat metabolism and cancer

Progressive weight loss and anorexia are frequent phenomena in cancer patients. Although cachexia is an expected occurrence in the terminal stages of nearly all malignancies, it may be a presenting sign when the tumor burden is quite small. Lipid depletion occurs out of proportion to the protein loss and accounts for most of the weight loss in cancer. Lipids, more specifically fatty acids, are the major source of fuel in mammals and may also be used in the synthesis of new cell products. Lipolysis and lipogenesis are under the influence of several important enzymes and peptide hormones that may be modulated by a variety of exogenous factors. There is evidence that cancer patients have lost the normal homeostatic responses to decreased energy intake or starvation that allow a decrease in oxygen consumption and protein sparing. An increase in Cori cycle activity or futile recycling of metabolic products occurs with a net energy expenditure rather than energy production. Clinical studies have shown that the body lipid depletion accompanying tumor progression is not solely secondary to decreased food intake and may be reproduced by the transplantation of certain noninvasive tumors to normal hosts. Elevated basal lipolysis has occasionally been seen early in tumor growth. Such findings suggest the presence of a tumor-associated factor responsible for this increase in lipid mobilization. Some of the potential mechanisms for the altered lipid metabolism seen in cancer have been discussed. Metabolic substrates may be remodeled and directed away from fuel-efficient into energy-requiring pathways. An increased energy expenditure may occur as a result of the energy costs of tumor synthesis, an uncoupling of oxidative phosphorylation, or energy-requiring futile cycling. An overall depletion of lipid may be the final outcome of the inhibition of lipid deposition. TNF/cachectin has recently been found to suppress the activity and synthesis of several key lipogenic enzymes, including lipoprotein lipase. Abnormalities in insulin secretion or sensitivity may be involved in the decrease of fat storage in malignancy. Insulin also exerts a significant antilipolytic effect by its antagonism of hormone-sensitive lipase. Mediators of lipolysis and abnormal lipid metabolism may occur in a number of clinical conditions and include ectopic hormone production, growth factors, and tumor-associated lipolytic factors (lipid mobilizing factor, toxohormone).

Skeletal muscle metabolism in mice bearing adenocarcinoma. I. Histochemical alterations in glycogenolytic, glycolytic, lipolytic and oxidative metabolism

Metabolism of triceps, pectoralis (in the vicinity of tumor) and gastrocnemius (away from the tumor) muscles in Swiss albino mice bearing adenocarcinoma has been studied histochemically with regard to content of glycogen, lipids, phosphorylase, aldolase, lipase, succinate dehydrogenase and cytochrome oxidase in the constituent fibres. At 9-10 weeks after transplantation of adenocarcinoma, a negligible glycogen content and decreased phosphorylase and aldolase activities are observed in the white, intermediate and red fibre types in the three muscles. Hypertrophy of fibres and occurrence of targetoid fibres is distinct in the muscles of tumor-bearing mice. The red fibres demonstrate a general loss of lipids, lipase, succinate dehydrogenase and cytochrome oxidase whereas the hypertrophied fibres reveal intense localization of these parameters in their central zones. The results indicate that a decline in glycogenolysis, glycolysis, lipolysis and oxidative metabolism in the various fibre types may contribute to the muscle weakness and muscle wasting in the adenocarcinoma-bearing mice.

Anorexia and weight loss: indicators of cachexia in small cell lung cancer

A study was conducted to determine the incidence and extent to which anorexia, a decrease in spontaneous food intake, contributes to the occurrence of cancer cachexia. Data for ten male subjects with small cell carcinoma of the lung are reported for a five-month period following diagnosis. Although body weights of the subjects at the time of diagnosis averaged less than 95% of the usual weight (weight 6 months prior to diagnosis), they were greater than 109% of the mean ideal weight. At five months, the mean weight (N = 8) was 88% of the preillness weight. From the time of diagnosis, there was a mean loss of 7.2 kg (15.8 lb). The urinary creatinine excretion was below the normal range, whereas the urinary urea nitrogen values were within the normal range. At the time of diagnosis, the mean triceps skin-fold measurements were approximately 80% of the standard reference for males. During the five-month period, the mean midarm muscle circumference determinations remained greater than 90% of the reference standard. The mean serum transferrin values were 10% or more below the reported lower range of normal, whereas the great majority of the serum albumin values were 3.0 g/dl or above during the five-month period. The mean caloric intake of 2,204 kcal at the time of diagnosis was only 86% of the estimated basal energy expenditure (BEE) times a factor of 1.5 used to account for moderate activity. Four months following diagnosis, the mean caloric intake had fallen to 1,702 kcal, only 67% of the BEE X 1.5 (calculated from the weight at diagnosis). The findings provide evidence of a decline in spontaneous food intake, a small decrease in body fat, and a greater than 13% weight loss. The oral intake was less than adequate for any activity beyond the basal state. Decreased intake could account for most of the weight loss observed in the subjects.

Enhanced tumor response to cycle-specific chemotherapy by parenteral amino acid administration

Forced feeding has been shown to effectively stimulate tumor metabolism in numerous animal models. Significant acceleration of tumor growth by exogenous nutrient administration is generally considered to be detrimental to the host. The present study was performed to determine if substrate-induced alterations in tumor metabolism could be exploited to enhance tumor response to cycle-specific chemotherapy. Following subcutaneous mammary tumor implantation (AC-33) and protein depletion, 39 female Lewis/Wistar rats were randomly assigned to one of four nutritional regimens for 48 hr: (1) protein-depleted food (0.03% protein) ad libitum po, (2) parenteral carbohydrate (18.6% dextrose), (3) parenteral amino acids (2.8% amino acids), or (4) total parenteral nutrition (18.6% dextrose/2.8% amino acids). Methotrexate (5 mg/kg im) was administered to all animals 2 hr after initiating these nutritional regimens. Tumor volume and host toxicity were monitored throughout the study. At sacrifice, significant reduction in tumor volume was observed in animals receiving parenteral amino acids (0.37 +/- 0.24 cm3) and total parenteral nutrition (0.25 +/- 0.18 cm3) compared to the group receiving protein-depleted food po (0.70 +/- 0.22 cm3) (p less than 0.01). In this animal model, the parenteral administration of amino acids with or without the addition of hypertonic dextrose was found to effectively potentiate tumor response to methotrexate without increasing host toxicity.

Hypoglycemia in mice injected with interferon inducers is not mediated by interferon

Injection of mice with several viral and nonviral inducers of interferon resulted in a marked hypoglycemia. Interferon is not responsible for this effect since inoculation of a potent antiserum to interferon (which neutralized the endogenous interferon) did not prevent hypoglycemia and administration of potent interferon preparations did not lower blood sugar. Hypoglycemia induced by Newcastle disease virus and polyriboinosinic-polyribocytidylic acid was further exacerbated by injection of insulin.

Anabolic profiles in late-stage cancer patients responsive to hydrazine sulfate

The anabolic profiles of 59 late-stage cancer patients responsive to hydrazine sulfate were examined; the drug had been given either as a sole agent or added to preexisting therapy to which the patients had become refractory. Most of the patients (79.7%) responded which Indicated Appetite Improvement (IAI), expressed by protocol-code, clinical evaluation and/or direct quantitation. In those patients receiving hydrazine sulfate alone the IAI was 86.1%; in those in whom hydrazine sulfate was added to pre-existing therapy the IAI was 69.6%. Of those cases expressed in direct quantitation the average weight gain for patients receiving hydrazine sulfate alone was 8.2 lbs, whereas the average weight gain for those with pre-existing therapy was 0.6 lbs (p = 0.01). The results suggest the use of hydrazine sulfate as a specific chemotherapy for cancer cachexia, and implicate ineffective concurrent or prior therapy as an apparent negative factor in the generation of anabolic response.

Host-tumor interaction and nutrient supply

Adequate parenteral nutritional support improves nutritional status in cancer patients, but its effect on tumor growth remains controversial. Using a transplantable mammary adenocarcinoma in a rat-TPN model, the relative effect of different exogenous intravenous nutrients on tumor growth and host maintenance was studied. Relative to chow controls, starvation increased host depletion without reducing tumor growth. Adequate carbohydrate calories alone neither improved host maintenance nor stimulated tumor growth, yet adequate amino acids alone did improve host maintenance but also stimulated tumor growth. Adequate amino acids and carbohydrates given simultaneously maximized both host maintenance and tumor growth. In contrast, an isocaloric, isonitrogenous, intravenous diet providing non-nitrogenous calories as fat promoted host maintenance equivalent to carbohydrate-based TPN with no tumor stimulation. This apparent differential utilization of fat calories by normal and malignant cells may permit manipulation of the relative benefit of parenteral nutrition to host or to tumor, permitting host repletion without tumor stimulation or alternatively tumor stimulation at appropriate times to increase sensitivity to phase-specific antineoplastic therapy.

Cachexia of malignancy: potential role of insulin in nutritional management

Patients manifesting the syndrome of cachexia of malignancy exhibit an abnormal diabetic glucose tolerance. In our patients this has been correlated with a marked resistance to administered insulin, while insulin receptors on monocytes are normal. Lipolysis remains responsive to the effects of insulin. The oxidation of FFA, as a substrate for metabolism, has been reported to be increased, and the utilization of glucose as a metabolic fuel is reduced. Increased Cori cycle activity has been demonstrated, which produces an enhanced gluconeogenesis from lactate and amino acids; there is an expenditure of 6 ATP for the synthesis of each mole of glucose. An attempt to interrupt the Cori cycle in man, using hydrazine sulfate to inhibit the enzyme phosphoenolpyruvate carboxykinase, has not resulted in reproducible clinical benefit. However, successful treatment of the underlying tumor may produce a total reversal of the cachexia syndrome, suggesting that neoplasms have the potential to elaborate an, as yet, unidentified metabolic toxin. The use of insulin to counteract the reported abnormalities should be examined as a possible supportive measure in the total nutritional management of the cancer patient.

Intravenous hyperalimentation as an adjunct to cancer chemotherapy

A 36 per cent response rate was obtained in fifty-eight nutritionally depleted patients with cancer who would otherwise have been denied adequate antitumor therapy because of the fear of complications from malnutrition and inanition. A positive correlation between the nutritional status of the patient and the chemotherapeutic tumor response was identified. Intravenous hyperalimentation can be a valuable adjunct to cancer chemotherapy by improving the nutritional status, increasing the total deliverable dose of anticancer agent per unit of time, and reducing the incidence and severity of the toxic gastrointestinal side effects without adversely stimulating malignant cell growth or producing septic complications.