DNA topoisomerase I and II expression in drug resistant germ cell tumours

Prospects of Topoisomerase Inhibitors as Promising Anti-Cancer Agents

Topoisomerases are very important enzymes that regulate DNA topology and are vital for biological actions like DNA replication, transcription, and repair. The emergence and spread of cancer has been intimately associated with topoisomerase dysregulation. Topoisomerase inhibitors have consequently become potential anti-cancer medications because of their ability to obstruct the normal function of these enzymes, which leads to DNA damage and subsequently causes cell death. This review emphasizes the importance of topoisomerase inhibitors as marketed, clinical and preclinical anti-cancer medications. In the present review, various types of topoisomerase inhibitors and their mechanisms of action have been discussed. Topoisomerase I inhibitors, which include irinotecan and topotecan, are agents that interact with the DNA-topoisomerase I complex and avert resealing of the DNA. The accretion of DNA breaks leads to the inhibition of DNA replication and cell death. On the other hand, topoisomerase II inhibitors like etoposide and teniposide, function by cleaving the DNA-topoisomerase II complex thereby effectively impeding the release of double-strand DNA breaks. Moreover, the recent advances in exploring the therapeutic efficacy, toxicity, and MDR (multidrug resistance) issues of new topoisomerase inhibitors have been reviewed in the present review.

Potential therapeutic targets shared between leishmaniasis and cancer

The association of leishmaniasis and malignancies in human and animal models has been highlighted in recent years. The misdiagnosis of coexistence of leishmaniasis and cancer and the use of common drugs in the treatment of such diseases prompt us to further survey the molecular biology of Leishmania parasites and cancer cells. The information regarding common expressed proteins, as possible therapeutic targets, in Leishmania parasites and cancer cells is scarce. Therefore, the current study reviews proteins, and investigates the regulation and functions of several key proteins in Leishmania parasites and cancer cells. The up- and down-regulations of such proteins were mostly related to survival, development, pathogenicity, metabolic pathways and vital signalling in Leishmania parasites and cancer cells. The presence of common expressed proteins in Leishmania parasites and cancer cells reveals valuable information regarding the possible shared mechanisms of pathogenicity and opportunities for therapeutic targeting in leishmaniasis and cancers in the future.

Prediction models for the viability of pulmonary metastatic lesions after chemotherapy in nonseminomatous germ cell tumors

OBJECTIVES

To analyze predictors associated with viable cells in pulmonary residual lesions after chemotherapy for metastatic testicular nonseminomatous germ cell tumors and to develop models to prioritize pulmonary resection.

METHODS

Between 2008 and 2017, 40 patients underwent pulmonary metastasectomy after chemotherapy for nonseminomatous germ cell tumors. We evaluated these patients, and 326 pulmonary residual lesions were confirmed using computed tomography and pathological evaluations. Relationships with outcomes were analyzed using logistic regression analyses. Risk prediction models were developed, and predictive probabilities for the risk of viable cells were estimated.

RESULTS

Histological examinations showed that 73 (22%) pulmonary residual lesions contained viable cells: teratomas, 46 (14%); and cancer cells, 37 (11%). Multivariate analyses showed that the predictors associated with cancer cells in the residual lesions were elevated tumor marker levels, multiregimen chemotherapy, increased tumor size 6 months before surgery and the histological composition of the primary lesion, including yolk sac tumors. Additional predictors associated with teratomas were aspect ratio and histological composition of the primary lesion, including teratomas.

CONCLUSIONS

Intratumoral heterogeneity contributes to nonseminomatous germ cell tumor chemoresistance, and primary lesion site yolk sac tumors and teratomas are associated with greater risks of viable cells. Increased residual lesion size during chemotherapy could also be a predictor. Our simple model can predict the presence of viable cells in residual lesions after chemotherapy, and it might assist in decision-making and prioritizing pulmonary residual lesion resection.

Clinical applications of recent molecular advances in urologic malignancies: no longer chasing a "mirage"?

As our understanding of the molecular events leading to the development and progression of genitourologic malignancies, new markers of detection, prognostication, and therapy prediction can be exploited in the management of these prevalent tumors. The current review discusses the recent advances in prostate, bladder, renal, and testicular neoplasms that are pertinent to the anatomic pathologist.

[Medicated serum prepared with Chinese herbal medicine Zhizhen Recipe down-regulates activity of nuclear factor-κB and expression of P-glycoprotein in human colorectal cancer multidrug-resistant cell line HCT-8/VCR]

OBJECTIVE

To investigate the effects of medicated serum prepared with Chinese herbal medicine Zhizhen Recipe (ZZR) on activity of nuclear factor-κB (NF-κB) and expression and function of P-glycoprotein (P-gp) in human colorectal cancer multidrug-resistant cell line HCT-8/VCR.

METHODS

The multidrug resistance of HCT-8/VCR cells was detected by cell counting kit-8 method, and the experimental concentrations of ZZR-medicated serum were determined by the same way. HCT-8 and HCT-8/VCR cells were treated with ZZR-medicated serum of medium dose for 24 h. The activity of NF-κB was determined by enzyme-linked immunosorbent assay. The intracellular distribution of P-gp was detected by laser scanning confocal microscopy, and the mean fluorescence intensity of rhodamine 123 was detected by flow cytometry.

RESULTS

ZZR-medicated sera with volume fraction of 8%, 16% and 32% of medium dose were confirmed as the experimental sera. Compared with the untreated group, NF-κB activities of the ZZR-medicated serum groups (ZZR-medicated serum with volume fraction of 8%, 16% and 32% of medium dose) were obviously down-regulated (P<0.01), which had a negative correlation with the concentrations. After interfering HCT-8/VCR with ZZR-medicated serum of different concentrations for 24 h, P-gp in HCT-8/VCR transmitted gradually from cell membrane to cytoplasm and nuclei. Nuclei became pyknotic and cracking. Compared with the untreated group, the mean fluorescence intensities of ZZR-medicated serum groups declined with concentration gradients (P<0.01). The efflux of intracellular rhodamine 123 decreased, the wave crest shifted to right, and the intracellular fluorescence intensity strengthened (P<0.01).

CONCLUSION

ZZR-medicated sera of experimental concentrations down-regulate activity of NF-κB and expression and function of P-gp in human colorectal cancer multidrug-resistant cell line HCT-8/VCR and the effect is related to the concentrations.

Topoisomerase I protein expression in primary colorectal cancer and recurrences after 5-FU-based adjuvant chemotherapy

PURPOSE

Our aim was to investigate whether chemotherapy with 5-FU induces an alteration in the levels of topoisomerase I (topo I) in colorectal neoplastic tissues

METHODS

Twenty-five colorectal cancer patients were included in our study; these had undergone surgical resection of the primary tumor, received post-operatively 5-FU-based adjuvant chemotherapy and then suffered from recurrences. In a standard three-step immunohistochemical procedure, a monoclonal antibody to topo I was applied in both specimens from each patient (one from the primary location and a second one from the recurrence). Statistical analysis was subsequently performed.

RESULTS

Malignant cells from the recurrences displayed a statistical significant increase, concerning the levels of topoisomerase I, by comparison with the primary tumors (P=0.01). The increase in topo I levels did not demonstrate significant correlations with Duke's stage (Fisher's Exact Test P value=0.496), differentiation grade (P value=0.661), localization (P value=0.072), patient sex (P value=0.434), nor with relapse free interval (P value=0.493). There was a statistically significant relationship between the age of patients and increase in topo I levels (P=0.011).

CONCLUSIONS

Topo I expression may be part of the malignant cells' phenotype in recurrent colorectal carcinomas, suggesting a potential role for Topo I in the acquisition of a metastatic phenotype. The increase of topo I immunohistochemical status is likely to be attributed to 5-FU and given the fact that high levels of topo I correlate with sensitivity to camptothecin, advanced colorectal cancer patients seem to benefit from topo I targeted anticancer drug therapy.

Topoisomerase II Alpha Expression in Testicular Germ Cell Tumors

OBJECTIVES

Inhibitors of topoisomerase II alpha (TopoIIalpha), an enzyme with a crucial role in DNA maintenance, are included in the chemotherapy protocols for testicular germ cell tumors (GCTs). Despite the success of current chemotherapy regimens, a significant number of patients experience relapse. We analyzed TopoIIalpha expression in primary and metastatic testicular GCTs because this enzyme is a target for some antineoplastic agents.

METHODS

Primary GCT specimens from 109 patients, including 57 seminomas and 52 mixed GCTs (41 embryonal carcinomas, 23 yolk sac tumors, 19 seminomas, 8 choriocarcinomas, 17 teratomas with immature elements, and 16 teratomas with mature elements), were obtained from our archives. The metastatic lesions from 11 of the patients with mixed GCTs included seven teratomas with mature components, five embryonal carcinomas, one yolk sac tumor, one choriocarcinoma, and one teratoma with immature components. Representative sections were subjected to immunohistochemistry with monoclonal antibody against TopoIIalpha, and the nuclear staining findings were evaluated.

RESULTS

Most embryonal carcinoma (100%), yolk sac tumor (95%), seminoma (88%), and choriocarcinoma (62%) components of the GCTs were TopoIIalpha immunoreactive. None of the teratoma specimens with mature elements expressed TopoIIalpha.

CONCLUSIONS

The results of our study have shown that TopoIIalpha is expressed in most seminomas, embryonal carcinomas, yolk sac tumors, and choriocarcinomas, suggesting a possible mechanism of sensitivity of these components to TopoIIalpha inhibitors. Teratomas with mature and immature elements expressed low levels of TopoIIalpha, which might contribute to their chemoresistance. These findings imply that the variable chemoresponsiveness of testicular GCTs could have an underlying molecular basis.

A phase II study using a topoisomerase I-based approach in patients with multiply relapsed germ-cell tumours

BACKGROUND

The outcome of patients with germ-cell tumours (GCTs), who relapse more than once or relapse with a mediastinal primary is poor. We have shown that topoisomerase 1 may be an attractive target in relapsed GCT. We investigated the role of irinotecan, paclitaxel and oxaliplatin (IPO) followed by topotecan-based high-dose therapy in responding patients, in this patient population.

PATIENTS AND METHODS

Twenty-eight patients with multiply relapsed gonadal and mediastinal GCT were recruited to this phase 2 study. All patients received IPO chemotherapy and 12 (43%) went on to receive high-dose therapy. The outcome of these patients was assessed using the Kaplan-Meier method with a median progression-free follow-up of 1 year.

RESULTS

Twenty patients (71%) responded to the therapy including five complete remissions (18%), 13 (46%) marker-negative partial responses and two (7%) marker-positive partial responses. Nine (32%) patients continue to be progression free, and the median survival for the whole group currently measures 17 months. Out of 12 individuals who received subsequent high-dose therapy consolidation, seven (58%) remain progression free. The commonest grade III/IV toxicity was infection (68%) and there were no IPO-related toxic deaths; there was one death from high-dose therapy.

CONCLUSION

Topoisomerase I-based IPO chemotherapy that lacks etoposide is very active in multiply relapsed GCT. This data merit further investigation.

Recent advances in management of patients with platinum-refractory testicular germ cell tumors

With the use of cisplatin-based combination chemotherapy, metastatic testicular germ cell tumors can be cured in 70-80% of patients, but patients refractory to cisplatin-based chemotherapy continue to have a very poor prognosis. Various chemotherapeutic agents have been evaluated in intensively pretreated or cisplatin-refractory patients, but as single agents, only orally administered etoposide, paclitaxel, gemcitabine, and, most recently, oxaliplatin have been shown to be active with selected patients achieving complete remissions. This has for the first time lead to clinical evaluation of combination chemotherapy regimens such as gemcitabine-paclitaxel or oxaliplatin-gemcitabine, demonstrating the feasibility of combination therapy in these heavily pretreated patients. High response rates of up to 45% were observed in particular with the latter combination. Salvage surgery remains a very important treatment option for patients with resectable disease. The molecular mechanisms of cisplatin resistance have been intensively studied, and several mechanisms have been discussed such as a decreased intracellular concentration of the drug, increased repair of the drug-induced damage, or an altered apoptotic response to this damage. This increasing knowledge may now allow design of new therapeutic options. Ongoing studies in refractory germ cell tumors are evaluating 3-drug regimens such as gemcitabine-paclitaxel-oxaliplatin but also biologic approaches such as inhibitors of the epidermal growth factor receptor or the vascular endothelial growth factor. This research may eventually allow the development of a noncross-resistant multidrug combination regimen that can be evaluated in an earlier line of therapy.

Chromosomes, genes, and development of testicular germ cell tumors

A literature review found 265 articles on testicular germ cell tumors (TGCTs) detailing the copy number of chromosomal regions and expression of 245 genes. An initial precursor stage, intratubular germ cell neoplasia (IGCN), is characterized by triploidization and an upregulation of KIT, ALPP, CCDN2, and ZNF354A, and a downregulation of CDKN2D. TGCT regularly have a series of chromosomal aberrations: a decrease in copy number at 4q21 approximately qter and 5q14 approximately qter; an increase at 7p21 approximately pter, 7q21 approximately q33, and 8q12 approximately q23 (especially high increase in seminoma); a decrease at 11p11 approximately p15 and 11q14 approximately q24; an increase at 12p11 approximately pter; a decrease at 13q14 approximately q31; an increase of 17q11 approximately q21 (only for nonseminoma); a decrease of 18q12 approximately qter; and an increase at 21q21 approximately qter, 22q11 approximately qter (only for seminoma), and Xq. Macroscopically overt TGCT is associated with a characteristic series of abnormalities in the retinoblastoma pathway including upregulation of cyclin D2 and p27 and downregulation of RB1 and the cyclin-dependent kinase inhibitors p16, p18, p19, and p21. TGCT thus has a synergistic pattern in gene expressions of the retinoblastoma pathway that is rare in other malignancies.

Cancer therapy: new targets for chemotherapy

The number two cause of mortality in developed countries is cancer. Despite the enormous effort put into cancer prevention, early diagnosis and treatment, it is likely that the incidence of the cancer morbidity and mortality will increase for the foreseeable future. This is due to various factors such as increased life expectancy, changes in environment and also the socio-economic situation around the world. Some cancer attracts more attention than others and increasingly epidemiological information is reaching the general public and is beginning to influence behavior. It is now well recognized that, for example, 1 of 8 women in the industrialized world will be diagnosed with breast cancer. Additionally, a strong correlation was established between lung cancer incidence and smoking and it is broadly accepted that the incidence of colon cancer is directly related to age and diet, and has been increasing over time. The current failure of preventive measures to significantly reduce the increasing incidence of these common tumors illustrates the importance of effective cancer treatment strategies, including chemotherapy. The combination of various anticancer drugs, given together with surgery and radiotherapy, gives hope to many patients. There has been recent evidence of improved therapeutic outcome with recent approaches and newer agents but for continuing effective chemotherapeutic treatment there is a need for a detailed understanding of their mechanisms of action and on the rationale of their application. This review attempts to provide up-to-date information regarding the development of new and innovative treatment strategies for cancer chemotherapy. Virtually, every year several of new targets for cancer therapy on both, cellular and molecular levels, are identified and new drugs enter not only clinical trials but also are included in well accepted and documented therapeutic protocols. As this review is in addition to our review published previously (Medical Principles and Practice 11, 2002, 117-125), we have tried to include new and innovative targets and drugs that attract attention at present. Although it is not possible to provide a complete list of all achievements and cover all work done in this field, we hope to be able to give some insight into this rapidly developing area.