ANTIBODY TO ONCOGENE PROTEIN PRODUCT AND ITS CONJUGATE WITH RICIN A-CHAIN

The proteins encoded by oncogene were thought to be tumor associated antigen. The protein P110 in MGC803, a human gastric cancer cell line, was purified as immunogen. The IgY to the gastric cancer was extracted from eggs laid by immunized hen. The IgY could react immunohistochemically with gastric cancers. Positive staining rates of PAF were 80% in gastric cancers and markedly higher than in cancers of other organs and normal gastric tissue. The IgY-Ricin A was synthesized by the IgY conjugated with Ricin A- chain. TCID50 of MGC803 treated by the IgY-Ricin A was 0. 01 mg/ml and markedly lower than other cell. These results showed the IgY-Ricin A were able to react with gastric cancers selectively.

Qualitative and Quantitative Studies of Polygene Proteins Expression in Esophageal Precancerous Lesions and Esophageal Carcinoma

Objective： To examine the expressions of MDM2, P53 and P27 proteins in chronic esophagitis, para-cancer mucosa and esophageal carcinoma. Methods： Immunohistochemistry was used to detect the expressions of MDM2, P53 and P27 proteins in forty-seven patients suffering from chronic esophagitis and eighty-five cases of esophageal carcinoma and corresponding para-cancer mucosa. Flow cytometry（（FCM） was applied to detect the quantities of these proteins expressed in fresh tissues of 48 cases of esophageal cancer and their para-cancer tissues and 24 cases of relative normal mucosa at the surface of cutting edge. Results： Immunohistochemistry results showed that the expressions of the three studied proteins were very similar in the epithelia of chronic esophagitis and para-cancer mucosa （P〉0.05）. Both the qualitative and quantitative studies displayed that the P53 protein had no expression and its accumulations would appear only in the early stages of esophagus canceration while the MDM2 and P27 proteins had different degrees of expressions in cases of normal esophageal mucosa. MDM2 protein markedly increased in the advanced stages of esophageal canceration. A quantitative study showed that the expression of P27 protein had a linearity of decreasing tendency （F=9.132, P=0.002） in the course of esophageal canceration. Conclusion： Chronic esophagitis may be a precancerous lesion. Owing to the changes of the P53 and P27 proteins, we can also conclude that these occur in the early stages of esophagus oncogenesis, however the changes of MDM2 expression may occur in the advanced stage of esophageal canceration.

Targeting the“undruggable”cancer driver genes:Ras,myc,and tp53

The term“undruggable”is to describe molecules that are not targetable or at least hard to target pharmacologically.Unfortunately,some targets with potent oncogenic activity fall into this category,and currently little is known about how to solve this problem,which largely hampered drug research on human cancers.Ras,as one of the most common oncogenes,was previously considered“undruggable”,but in recent years,a few small molecules like Sotorasib(AMG-510)have emerged and proved their targeted anti-cancer effects.Further,myc,as one of the most studied oncogenes,and tp53,being the most common tumor suppressor genes,are both considered“undruggable”.Many attempts have been made to target these“undruggable”targets,but little progress has been made yet.This article summarizes the current progress of direct and indirect targeting approaches for ras,myc,two oncogenes,and tp53,a tumor suppressor gene.These are potential therapeutic targets but are considered“undruggable”.We conclude with some emerging research approaches like proteolysis targeting chimeras(PROTACs),cancer vaccines,and artificial intelligence(AI)-based drug discovery,which might provide new cues for cancer intervention.Therefore,this review sets out to clarify the current status of targeted anti-cancer drug research,and the insights gained from this review may be of assistance to learn from experience and find new ideas in developing new chemicals that directly target such“undruggable”molecules.

Gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine in rat with ulcers and expressions of ras and c-erbB2 genes

Objective: To observe the series of pathological changes during the development of gastric adenocarcinoma in ulcerative rats induced by N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), and the expression profile of related oncogenic protein.Methods: MNNG was administered in rats with ulcers due to acetic acid treatment to induce gastric cancer, and the protein expressions of ras and c-erbB2 genes in the ulcer were examined immunohistochemically along with pathological examination.Results: The incidence of gastric adenocarcinoma in the model group reaches 40% (6/15), while none of the rats developed cancer in the control group with ulcers.Positive expressions of the proteins of p21ras and c-erbB2 were observed in the tissues undergoing canceration in the 6 rats of model group, but were not observed in the 5 control rats; p53 protein expression, however, failed to be detected in both groups.Conclusion: A new animal model of gastric cancer has been established in rats with gastric ulcer after MNNG treatment, which may facilitate the pharmacological research of gastric cancer.

Detection of SYT-SSX fusion transcripts in paraffin-embedded tissues of synovial sarcoma by reverse transcription-polymerase chain reaction

OBJECTIVE: To assess the feasibility of detecting SYT-SSX fusion transcripts in paraffin-embedded tissues of synovial sarcoma by reverse transcription-polymerase chain reaction (RT-PCR). METHODS: RT-PCR was used to amplify the SYT-SSX fusion transcripts using archival formalin-fixed paraffin-embedded tumor specimens from a series of 37 synovial sarcoma cases. To investigate the specificity of the SYT-SSX fusion transcripts, a variety of non-synovial sarcoma tumors were included in the study as negative controls. The detected messages derived from fusion genes were confirmed by subsequent sequence analysis. RESULTS: SYT-SSX fusion transcripts were detected in 33 of 37 (89.2%) synovial sarcomas. None of the 34 cases of non-synovial sarcoma tumors showed amplified products of SYT-SSX fusion transcripts, although PBGD mRNA was detected in all specimens. Among 33 SYT-SSX-positive synovial sarcomas, 22 tumors had an SYT-SSX 1 fusion transcript, whereas 6 tumors had an SYT-SSX2 fusion transcript. Fusion types can not be distinguished in the remaining 5 cases. There was a significant relationship between SYT-SSX fusion type and histologic subtype. All 10 biphasic synovial sarcomas had the SYT-SSX1 fusion, whereas all tumors with SYT-SSX2 were of monophasic morphology (P

Effect of all-trans retinoic acid and arsenic trioxide on tissue factor expression in acute promyelocytic leukemia cells

OBJECTIVE: To study the effect of all-trans retinoic acid (ATRA) and arsenic troxide (As2O3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia (APL) cells in vivo and in vitro. METHODS: PCA from freshly isolated APL blasts from APL patients treated with ATRA or As2O3 was detected using a one-stage clotting assay. TF antigen was detected by ELISA and TF mRNA by RT-PCR. The maturation sensitive (NB4) or resistant subclones (NB4-R1) of the promyelocytic NB4 cell line, as well as U937 cells infected with pMSCV-PML-RARa treated with or without ATRA or As2O3, were also examined. RESULTS: Both ATRA and As2O3 can down-regulate the TF antigen, its mRNA transcription and membrane PCA of APL cells in vivo and in vitro, in a time-dependent manner. The TF antigen level in PML-RARa + U937 cells was significantly higher than that in U937 cells infected with retrovirus vector. Both ATRA and As2O3 can also down-regulate the TF antigen in U937 cells transfected with or without PML-RARa. CONCLUSION: Tissue factor expression and PCA in APL cells may be down-regulated by ATRA and As2O3. By down-regulating TF expression, As2O3 might also be used to improve the DIC-related hemorrhage in APL. Our data indicate that elevated TF antigen in PML-RARa + U937 may be related to the fusion protein PML-RARa. The down-regulating effect of ATRA and As2O3 on TF expression in U937 cells might not involve this fusion protein.

Effects of anti-HPV16E6-ribozyme on phenotype and gene expression of a cervical cancer cell line

OBJECTIVE: To investigate the effects of anti-HPV16E6-ribozyme (HRz) on phenotype and gene expression of a cervical cancer cell line. METHODS: HRz was designed by computer programs. HRz's activity was identified by cleavage experiments in vitro. HRz and empty eukaryotic plasmids were transfected into CaSKi cells with lipofectin, then renamed CaSKi-R and CaSKi-P, respectively. The expression of ribozyme in transfected cells was observed by RNA dot blot. The amounts of E6 mRNA in three kinds of cells lines were detected by Northern blot. Cell growth curves and soft agar forming ability were studied. The ability of each cell line to form tumors was assessed in nude mice. Apoptosis rates and expression of c-myc, bcl-2, p53 and Fas were detected by flow cytometry (FCM). Antigens of tumor cells, HLA-1, HLA-2, B7-1 and B7-2 were also detected. NK, LAK, and CD(3)AK cells were induced. Their cytotoxicities were detected in CaSKi-R, CaSKi-P, and CaSKi cells. RESULTS: In vitro cleavage reaction demonstrated that HRz could cleave HPV16E6 mRNA in a site-specific manner. HRz could be expressed stably in transfected CaSKi cells. Northern blot analysis showed that E6 mRNA levels were lower in CaSKi-R than in CaSKi. The growth rate of CaSKi-R was slower than those of CaSKi and CaSKi-P. The soft agar-forming rate of CaSKi-R was lower compared with those of CaSKi and CaSKi-P cells. The ability of CaSKi-R to form tumors in nude mice was also poor. The apoptosis rate of CaSKi-R cells was much higher than those of CaSKi and CaSKi-P. HRz could reduce the expression of E6, c-myc and bcl-2 proteins, and increase the expression of p53 as well. HRz could increase the expression of HLA-2, B7-1 and B7-2 antigens. The cytotoxicity of NK, LAK and CD(3)AK cells was much higher in CaSKi-R than in CaSKi-P and CaSKi cells. CONCLUSION: HRz not only reverses the malignant phenotype of CaSKi cells partially, but also induces apoptosis in the cells, and increases sensitivity of CaSKi cells to immune cells.