Hormones, vitamins, and growth factors in cancer treatment and prevention: A critical appraisal

Targeting Akt-associated microRNAs for cancer therapeutics

The uncontrolled growth and spread of abnormal cells because of activating protooncogenes and/or inactivating tumor suppressor genes are the hallmarks of cancer. The PI3K/Akt signaling is one of the most frequently activated pathways in cancer cells responsible for the regulation of cell survival and proliferation in stress and hypoxic conditions during oncogenesis. Non-coding RNAs are a large family of RNAs that are not involved in protein-coding, and microRNAs (miRNAs) are a sub-set of non-coding RNAs with a single strand of 18-25 nucleotides. miRNAs are extensively involved in the post-transcriptional regulation of gene expression and play an extensive role in the regulatory mechanisms including cell differentiation, proliferation, apoptosis, and tumorigenesis. The impact of cancer on mRNA stability and translation efficiency is extensive and therefore, cancerous tissues exhibit drastic alterations in the expression of miRNAs. miRNAs can be modulated by utilizing techniques such as miRNA mimics, miRNA antagonists, or CRISPR/Cas9. In addition to their capacity as potential targets in cancer therapy, they can be used as reliable biomarkers to diagnose the disease at the earliest stage. Recent evidence indicates that microRNA-mediated gene regulation intersects with the Akt pathway, forming an Akt-microRNA regulatory network. miRNAs and Akt in this network operate together to exert their cellular tasks. In the current review, we discuss the Akt-associated miRNAs in several cancers, their molecular regulation, and how this newly emerging knowledge may contribute greatly to revolutionize cancer therapy.

Anorexia nervosa and cancer: a protocol for a systematic review and meta-analysis of observational studies

BACKGROUND

Anorexia nervosa is characterized by a severe restriction of caloric intake, low body weight, fear of gaining weight or of becoming fat, and disturbance of body image. Pathogenesis of the disorder may include genetic predisposition, hormonal changes and a combination of environmental, psychosocial, and cultural factors. Cancer is the second leading cause of death worldwide. At present, no systematic reviews and meta-analyses have evaluated the risk of cancer in people with anorexia nervosa. The objective of this study will be to evaluate the association between anorexia nervosa and the risk of developing or dying from cancer.

METHODS/DESIGN

This study protocol is part of a systematic collection and assessment of multiple systematic reviews and meta-analyses (umbrella review) evaluating the association of cancer and multiple central nervous system disorders. We designed a specific protocol for a new systematic review and meta-analysis of observational studies of anorexia nervosa with risk of developing or dying from any cancer. Data sources will be PubMed, Embase, Scopus, Web of Science, and manual screening of references. Observational studies (case-control and cohort) in humans that examined the association between anorexia nervosa and risk of developing or dying from cancer will be sought. The primary outcomes will be cancer incidence and cancer mortality in association with anorexia nervosa. Secondary outcomes will be site-specific cancer incidence and mortality, respectively. Screening of abstracts and full texts, and data abstraction will be performed by two team members independently. Conflicts at all levels of screening and abstraction will be resolved through discussion. The quality of studies will be assessed by using the Ottawa-Newcastle scale by two team members independently. Random effects models will be conducted where appropriate. Subgroup and additional analyses will be conducted to explore the potential sources of heterogeneity. The World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) criteria and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used for determining the quality of evidence for cancer outcomes.

DISCUSSION

Findings from this systematic review will inform an ongoing umbrella review on cancer and central nervous system disorders. Our systematic review and meta-analysis of observational studies will establish the extent of the epidemiological evidence underlying the association between anorexia nervosa and cancer.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017067462.

Steroid-linked nitrogen mustards as potential anticancer therapeutics: a review

Nitrogen mustards, an important class of drugs for cancer therapy, are known as DNA alkylating agents. The nitrogen mustards are highly reactive and, as a consequence, lack of selectivity and produce several adverse side effects. In order to minimize these undesirable effects, the attachment of nitrogen mustards to a steroidal hormone with affinity for its receptor can lead to highly selective and less toxic antineoplastic therapeutics. This review will focus on the design, synthesis and evaluation of such steroid-nitrogen mustard hybrids as antineoplastic agents. Among these compounds, modified steroids with aromatic nitrogen mustards linked by an ester function were found to have better DNA alkylating properties, improved selectivity as well as low toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Chemoprevention of breast cancer

Breast cancer remains the second leading cause of malignancy-related death in women in the USA, regardless of advances in novel therapeutic agents. High priority should be given to research aimed at the study of pharmacological and natural compounds that could potentially prevent the development of breast cancer in susceptible patients. Tamoxifen has been shown to reduce the incidence of estrogen receptor-positive invasive breast cancer in women with a high risk of developing this condition by nearly 50%, and studies in osteoporosis have revealed a similar protective effect of raloxifene in postmenopausal women. The aromatase inhibitors are superior to tamoxifen in reducing the recurrence of breast cancer in postmenopausal women; large clinical trials are currently evaluating the chemopreventive effect of these agents. The list of agents with the potential for chemoprevention in breast cancer is extensive and continues to expand. There is an immense need to develop drugs that will decrease the incidence of estrogen receptor-negative breast cancer in women at high risk of developing the disease. Herein, we review the most important chemopreventive agents in breast cancer and clinical trials that have evaluated their efficacy.

Structure???anti-leukemic activity relationship study of B- and D-ring modified and non-modified steroidal esters of chlorambucil

In order to study the role of the steroidal moiety on the expression of anti-leukemic activity, we synthesized six derivatives of chlorambucil (CHL), and tested them on leukemias P388 and L1210 in vivo and in normal human lymphocytes in vitro. Five of the six tested compounds produced submultiple toxicity, while the measured anti-leukemic potency was significantly increased. The lactamization of the B-steroidal ring rendered the molecules more potent, but the corresponding 7-oxidized derivatives proved better in both leukemias tested. The lactamization of the D-steroidal ring afforded potent compounds, regardless of the configuration of the B-ring. The best among all derivatives contains both chemical modifications and is intended as a promising key molecule that must be further studied. We speculate that in leukemic cells a tumor-specific protein is overexpressed, the steroid has the ability to bind and block this protein from carrying out its normal function, and the drug-protein complex prevents the repair of the adducts. The synthesis, physicochemical and spectroscopic data of these compounds and a modified route for the synthesis of CHL are also reported.

Cancer is a functional repair tissue

When a wound occurs, growth and repair genes (GR genes, such as oncogenes, proto-oncogenes, etc.) in surrounding cells are activated and secretion of growth and repair factors (GR factors, such as growth, stem cell, and stimulating factors, etc.) is induced to heal the wound. However, if the wound is persistent due to chronic physical (radiation, electromagnetic field, trauma, particles, etc.), chemical (carcinogens, toxic chemicals, heavy metals etc.) or biological (aging, free radicals, inflammation, nutrient deficiency, bacteria and virus infections, stress, etc.) damage, amplification of GR gene activation in surrounding cells may lead to a clinical cancer. Based on the commonalities between cancer and wound healing, a new hypothesis of cancer is presented: malignancies are not passive mutated useless masses; rather, they are functional tissues produced by GR gene activation to secrete GR factors in an effort to heal persistent wounds in the body. Based on the hypothesis, current cancer treatments aimed at killing cancer cells only may be misguided. The logical extension of the hypothesis is that cancer treatment focused on wound healing by limiting causes of persistent wounds, providing repair cells, GR factors, and substrates required by repair cells may yield more fruitful results than treatments focused on killing cancer cells alone. Spontaneous regressions of cancer, although rare, may be successful examples of serendipitous spontaneous wound healing. Standard therapies aimed at killing cancer cells, should be limited to adjuvant status for limiting symptoms or buying time for completion of the wound healing process. Attempts to destroy cancer cells without healing underlying persistent wounds will allow for eventual recurrence.

Effects of retinoic acid steroidal analogs on human leukemic HL60 cell proliferation in vitro and on angiogenesis in vivo

Retinoic acid (RA) can be regarded as a pharmacological agent commonly used for its ability to affect growth and differentiation of a variety of cell types, such as acute promyelocytic leukemic and endothelial cells. In the present work we studied the effect of all-trans-RA (ATRA) and its steroidal analogs EA-4, EA-136 and EA-137 on the growth of human promyelocytic HL-60 cells in vitro. The specific steroidal substrates were chosen in order to further investigate their ability to improve the pharmacological properties of conjugated antileukemic agents. ATRA decreased the number of HL60 cells from the first 24 h after its addition to the cell culture medium. The decrease was significant at concentrations higher than 10(-5) M. All the analogs tested also decreased the number of HL60 cells with an IC50 similar to that of ATRA, except for EA-4 whose IC50 was almost two orders of magnitude lower than that of ATRA, 72 h after its addition to the cell culture medium. Since angiogenesis is important for the growth of hematological malignancies, we furthermore studied the effect of ATRA and its analogs on the formation of new capillaries in the in vivo chicken embryo chorioallantoic membrane (CAM). ATRA, EA-136 and EA-137 induced angiogenesis in the CAM, increased the layer of CAM keratinocytes, and resulted in a significant degree of extravasation. EA-4 had no effect on either angiogenesis or tissue structure in general. It seems that the retinoid EA-4 is a promising agent for the inhibition of human leukemia cell growth.

Synthetic approaches for the synthesis of a cytostatic steroidal B-D bilactam

A new synthetic procedure and a modification of the original method described in the literature for the synthesis of the steroidal B-D bilactam, 3 beta-hydroxy-7 alpha,17 alpha-diaza-B,D-dihomo-5-androsten-7,17-dione are reported. The key step in the modified method involved protection of the D-lactamic nitrogen atom of 3 beta-acetoxy-17 alpha-aza-D-homo-5-androsten-17-one using a reagent of specific electrophilicity (due to the stereoelectronic properties of the cyclic amide), as Beckmann rearrangement of the B-steroidal ring was hindered, possibly via long range effects, by the presence of the unprotected D-lactamic moiety. Using the 3 beta-acetoxy-5-androsten-17-one as starting material, a new synthetic procedure was developed through ketalization of the 17-ketone and allylic oxidation to the 7-ketone, which was subsequently followed by Beckmann rearrangement of the B- and D-steroid rings. Both approaches resulted in 45 and 67% yields of the desired B,D-bilactam, respectively, in contrast to the 15% yield, which has been reported in the literature.

Green tea constituent epigallocatechin-3-gallate inhibits angiogenic differentiation of human endothelial cells

Several independent research studies have shown that consumption of green tea reduces the development of cancer in many animal models. Epidemiological observations, though inconclusive, are suggesting that green tea consumption may also reduce the risk of some cancers in humans. These anti-carcinogenic effects of green tea have been attributed to its constituent polyphenols. Angiogenesis is a crucial step in the growth and metastasis of cancers. We have investigated the effect of the major polyphenolic constituent of green tea, epigallocatechin-3-gallate (EGCG), on the tube formation of human umbilical vein endothelial cells (HUVEC) on matrigel. Tube formation was inhibited by treatment both prior to plating and after plating endothelial cells on matrigel. EGCG treatment also was found to reduce the migration of endothelial cells in matrigel plug model. The role of matrix metalloproteinases (MMP) has been shown to play an important role during angiogenesis. Zymography was performed to determine if EGCG had any effect on MMPs. Zymographs of EGCG-treated culture supernatants modulated the gelatinolytic activities of secreted proteinases indicating that EGCG may be exerting its inhibitory effect by regulating proteinases. These findings suggest that EGCG acts as an angiogenesis inhibitor by modulating protease activity during endothelial morphogenesis.

Chronomodulated chemotherapy: clinical value and possibilities for dissemination in the United States

Modern medicine has been relatively slow to apply chronotherapeutic principles to standard oncologic practice. Despite the impressive body of evidence supporting the use of chronochemotherapy, with only a rare exception most oncology clinics in the United States lack the expertise and capability to implement it. At the same time, American medicine has increasingly come to recognize the importance of toxicity mitigation, cytoprotection, and quality of life for patients undergoing cancer treatment. However, toxicity mitigation strategies such as chronomodulated infusional chemotherapy and novel cytoprotective agents are not widely embraced by U.S. physicians. This article explores some reasons why this situation exists, including the influence of non-medical biases that may affect management decisions on the application of chemotherapy. The author conducted a survey of U.S. companies representing the three private insurance payers available (HMO, PPO, Indemnity) as well as representatives of Medicare and Medicaid. Responses to the survey confirmed that U.S. insurers do not at present officially reimburse for chronotherapy; however, changes will come about through educational efforts aimed at increasing awareness among insurers as to the clinical benefits and cost-effectiveness of this mode of treatment. At this juncture, the outlook for cancer chronotherapy as a first-line approach to the treatment of metastatic cancer in the United States remains uncertain. Under the current method of insurance reimbursement, the advancement of chronotherapy in the United States is threatened despite evidence that such treatment is both therapeutically sound and cost-effective.

Role of lipids, lipoproteins and vitamins in women with breast cancer

OBJECTIVES

Improper balance between the production of reactive oxygen metabolites (ROMs), and antioxidative defense system have been defined as oxidative stress in various pathologic conditions. Lipids, lipoproteins and antioxidative vitamins have been associated with the risk of breast cancer. The present case-control study was conducted to investigate the status of antioxidative vitamins (A, C and E), lipids (total cholesterol; TC and triglycerides; TG), lipoproteins (high-density lipoprotein cholesterol; HDL-C and low-density lipoprotein cholesterol; LDL-C) and retinol-binding protein (RBP) in breast cancer patients. The aim of the study was to find out oxidative stress in breast cancer.

DESIGN AND METHODS

Plasma lipids, lipoproteins and vitamins were estimated in 54 untreated breast cancer patients of different clinical stages and in 42 age- and sex-matched controls.

RESULTS

Plasma TC (p < 0.05), and LDL-C and TG (p < 0.01) were found to be significantly elevated among breast cancer patients as compared to the controls. On the other hand, plasma HDL-C concentration (p < 0.001) and vitamin C and E (p < 0.01) were observed significantly decreased in breast cancer patients than in the controls. The maximum changes in plasma TC, and vitamin C and E concentrations were observed in breast cancer patients with stage IV when compared with controls.

CONCLUSION

The study suggests that higher levels of TC and TG may play important role in carcinogenesis. Furthermore, the elevated plasma LDL-C concentration, which is more susceptible to oxidation, may result in higher lipid peroxidation in breast cancer patients. However, decreased concentrations of HDL-C and vitamin C and E are not likely to be sufficient enough to counter higher ROMs production reported earlier in breast cancer patients that may cause oxidative stress leading to cellular and molecular damage thereby resulting in cell proliferation and malignant conversions.

Prevention of lung cancer

Lung cancer is the major cause of death in industrialized western societies. Its link to tobacco abuse is well established and efforts should be made to eliminate this potent environmental carcinogen. The concept of chemoprevention, the use of agents to inhibit and reverse lung cancer carcinogenesis, has great appeal. The CARET study, conducted in 18,000 high-risk smokers in the US, found that a combination of beta-carotene and retinyl palmitate resulted in a 28% increase in the incidence of lung cancer. A similar study conducted in Finland, the ATBC trial utilizing alpha tocopherol and beta-carotene, had similar findings for the group taking beta-carotene. These two trials have caused a rethinking of the use of natural compounds as chemoprevention agents. These agents should no longer be regarded as harmless, but as having potential toxicities. A new approach in the chemoprevention of cancer has been the concept of surrogate endpoints, biological changes that are on the pathway to cancer. Trials are underway to determine what are appropriate surrogate endpoints for lung cancer chemoprevention trials.

Prevention of breast cancer

With the advent of screening and the increased incidence of breast cancer, concern for the prevention of breast cancer has become forefront in today's society. Determining individual risk is the key to prescribing prevention. Prevention of breast cancer is still under clinical investigation with only one drug, tamoxifen, showing benefit in high risk patients. This paper reviews the possible sites for prevention of neoplastic transformation via biomarkers in a breast cell as well as the investigational drugs and their potential use in the chemoprevention of breast cancer.

Signal transduction events elicited by natural products: role of MAPK and caspase pathways in homeostatic response and induction of apoptosis

Many natural products elicit diverse pharmacological effects. Using two classes of potential chemopreventive compounds, the phenolic compounds and the isothiocyanates, we review the potential utility of two signaling events, the mitogen-activated protein kinases (MAPKs) and the ICE/Ced-3 proteases (caspases) stimulated by these agents in mammalian cell lines. Studies with phenolic antioxidants (BHA, tBHQ), and natural products (flavonoids; EGCG, ECG, and isothiocyanates; PEITC, sulforaphane), provided important insights into the signaling pathways induced by these compounds. At low concentrations, these chemicals may activate the MAPK (ERK2, JNK1, p38) leading to gene expression of survival genes (c-Fos, c-Jun) and defensive genes (Phase II detoxifying enzymes; GST, QR) resulting in survival and protective mechanisms (homeostasis response). Increasing the concentrations of these compounds will additionally activate the caspase pathway, leading to apoptosis (potential cytotoxicity). Further increment to suprapharmacological concentrations will lead to nonspecific necrotic cell death. The wider and narrow concentration ranges between the activation of MAPK/gene induction and caspases/cell death exhibited by phenolic compounds and isothiocyanates, respectively, in mammalian cells, may reflect their respective therapeutic windows in vivo. Consequently, the studies of signaling pathways elicited by natural products will advance our understanding of their efficacy and safety, of which many may become important therapeutic drugs of the future.

Coexpression of CD9 augments the ability of membrane-bound heparin-binding epidermal growth factor-like growth factor (proHB-EGF) to preserve renal epithelial cell viability

BACKGROUND

Transfection of renal epithelial cells (NRK 52E) with membrane-associated heparin-binding epidermal growth factor-like growth factor (proHB-EGF) increased renal epithelial cell survival by promoting cell-cell and cell-extracellular matrix interactions. ProHB-EGF has been shown to form a complex in the plasma membrane with the tetraspanin CD9, an interaction that significantly increases the effectiveness of proHB-EGF as a juxtacrine mitogenic agent.

METHODS

We examined whether the coexpression of proHB-EGF and CD9 would increase renal epithelial cell survival. CD9 was stably transfected into NRK 52E cells, either alone (NRKCD9) or together with proHB-EGF (NRKboth).

RESULTS

Juxtacrine mitogenic activity of NRKCD9 was no different than in cells transfected with vector alone (NRKvector), but was increased by NRKboth; juxtacrine mitogenic activity by NRKboth was twofold greater than when proHB-EGF was transfected alone (NRKproHB-EGF). When grown in 10% fetal calf serum, growth rates were similar among all transfectants. However, in 1% fetal calf serum, NRKproHB-EGF grew 50% faster than NRKvector or NRKCD9, and NRKboth grew 20% to 50% faster than NRKproHB-EGF at one, two, and three days of culture. NRKproHB-EGF attachment to plastic substratum at one, two, and three hours was 250% greater than that of NRKvector, and NRKboth was 20% to 30% greater than that of NRKproHB-EGF. Coating plates with either poly 2-hydroxyethyl methacrylate or the GRGDTP peptide prevented normal cell-extracellular matrix attachment, and NRKvector or NRKCD9 failed to attach or form cell-cell attachments. NRKproHB-EGF exhibited 300% and NRKboth exhibited 600% greater cell viability under these conditions. Expression of type I and type III collagen mRNA was enhanced similarly in NRKproHB-EGF and NRKboth, but the expression of beta1 integrin was up-regulated only in NRKboth.

CONCLUSIONS

Coexpression of proHB-EGF and CD9 may render the renal epithelial cells more resistant to disruption of cell-cell and cell-matrix interactions and could accelerate the re-establishment of these attachments.

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.